Report on Issues
Related to the Aerial Eradication of Illicit Coca in Colombia
-Report Home Page
Released by the Bureau for International Narcotics and Law Enforcement
Affairs
September 2002
Response from EPA Assistant
Administrator Johnson to Secretary of State, August 19, 2002
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
OFFICE OF
PREVENTION, PESTICIDES AND
TOXIC SUBSTANCES
The Honorable Colin L. Powell, Secretary
U.S. Department of State
Washington, D.C. 20520
Dear Secretary Powell:
We are enclosing our consultation review as per your request to
Environmental Protection Agency (EPA) Administrator Christine Todd Whitman, for
consultation on the potential human health and environmental effects of the
aerial coca eradication program in Colombia, pursuant to the Foreign Operations,
Export Financing, and Related Programs Appropriation Act (P.L 107-115).
Administrator Whitman has asked me to respond on her behalf because my office
has primary oversight responsibility for pesticides, and the nature of this
consultation centers around the technical aspects of chemicals used in the
aerial fumigation of coca.
The Foreign Operations, Export Financing, and Related Programs
Appropriation Act specifically requires the Department of State to consult with
EPA on whether (1) "aerial coca fumigation is being carried out in accordance
with regulatory controls required by the EPA as labeled for use in the United
States .... ; and (2) whether the chemicals used in the aerial fumigation of
coca, in the manner in which they are being applied, do not pose unreasonable
risks or adverse effects to humans or the environment..."
As part of our consultation review, we considered the full range of
available scientific information from laboratory and field testing and incident
reports. Our consultation review evaluates the potential impact to human health
and the environment from the eradication program, based on information provided
by Department of State, on the pesticide used (glyphosate), inert ingredients,
and the application rates and methods, In addition, Agency scientists reviewed
scientific studies on glyphosate, conducted a limited literature search for
human health incidents related to glyphosate use, and examined information on
glyphosate use conditions in the United States. We also considered information
provided by non-governmental organizations, concerning effects reportedly
connected to coca eradication in Colombia.
Glyphosate is widely used in the United States. Based upon EPA reviews of
domestic use conditions, glyphosate appears to be one of the most safely-used
pesticides in the U.S. EPA's regulatory authority for domestic pesticide use
allows significant controls through pesticide labeling and compliance and
enforcement infrastructure implemented with the states and other federal
agencies. Recognizing that these mechanisms are not available to EPA in
Colombia, the Agency has evaluated potential risks associated with the coca
eradication program and identified areas where Department of State should pay
particular attention to minimize the potential for adverse effects.
I trust that the attached document will assist you in preparing your
response to Congress. Please let me know if you have additional questions
concerning this consultation review.
Sincerely,
Stephen L. Johnson
Assistant Administrator
U.S. Environmental Protection Agency Office of
Pesticide Programs Details of the Consultation for Department of State Use of
Pesticide for Coca Eradication Program in Colombia, August 2002
Table of Contents
CONSULTATION REVIEW OF THE USE OF PESTICIDE FOR COCA ERADICATION IN
COLOMBIA
BACKGROUND
The Department of State currently assists the Government of Colombia with
training, contractor support, financial assistance, and technical and scientific
advice for an aerial pesticide spraying program designed to eradicate illicit
crops (coca and poppy). In accordance with a provision in its 2002
Appropriations Bill, Department of State has consulted with the U.S.
Environmental Protection Agency (EPA) on two specific questions: that fumigation
is "...being carried out in accordance with regulatory controls required by the
Environmental Protection Agency as labeled for use in the United States" and,
that the chemicals being used "...in the manner they are being applied, do not
pose unreasonable risks or adverse effects to humans or the environment."
FINDINGS
EPA has reviewed information provided by Department of State concerning
the pesticide formulation applied (combination of the pesticide active
ingredient, glyphosate, and inert ingredients), and application rates and
methods. According to the most recent figures (1999 sales and usage) glyphosate
is the most widely used conventional pesticide in the United States. The Agency
evaluates all pesticides used in the U.S. to determine whether they meet the
U.S. safety standard of no unreasonable adverse effects. Consequently, EPA has a
significant amount of information about glyphosate from a health and
environmental standpoint because of our reviews of use conditions in the U.S. In
the U.S., the Agency can assure significant controls on use and potential health
and environmental impacts through the pesticide label, and through a state
infrastructure which governs label compliance to address issues such as drift
and worker and bystander exposure.
Based on a comparison of the glyphosate use pattern in Colombia, as
described by the Department of State, and use in the U.S., EPA determined that
the most equivalent U.S. uses of glyphosate would be forestry or rights-of-way.
The glyphosate product which has been identified to us as used in Colombia is
registered in both the U.S. and Colombia, although it has never been marketed in
the U.S. The Agency found application rates described as used in Colombia to be
within the parameters listed on U.S. labels. The addition of a spray adjuvant
(to facilitate the formulation adhering to and penetrating the coca plant) is
also in keeping with U.S. practice. While the specific spray adjuvant product
identified as that used in Colombia is not sold in the U.S., similar substances
and products are commonly used. Most U.S. labels for forestry and right-of-way
use of glyphosate suggest application by helicopter. Since application in
Colombia is done by fixed-wing aircraft, it is likely conducted at a higher
speed and from a greater altitude, than would be typical in the U.S. Department
of State has assured the Agency that mixers/loaders and applicators of the
glyphosate formulation receive training comparable to U.S. label requirements
for glyphosate products including the use of personal protective equipment such
as gloves and goggles.
As for potential human health effects of the coca eradication program,
there are no risks of concern for glyphosate, per se, from dermal or
inhalation routes of exposure, since toxicity is very low. There is concern for
acute eye toxicity due to an inert ingredient in the glyphosate formulated
product used to treat coca. The potential eye effects are related to an inert
ingredient, not the glyphosate itself, and greatest potential for exposure is
expected for workers mixing and loading the concentrated glyphosate product. The
components of the spray adjuvant, Cosmoflux 411F, are substances with low oral
and dermal toxicity that have been approved for use in/on food by EPA and the
Food and Drug Administration. There are no expected toxicological effects of
concern for acute (short-term) or chronic (long-term) dietary exposure through
food and water from the coca eradication program. Incident data from Colombia
involving humans, livestock, mammals and birds, are based on potential exposure
to glyphosate from fumigation of poppy fields, which may differ from use of and
exposure to glyphosate from coca eradication, so conclusions should be made
cautiously.
Relative to the potential environmental effects of the spraying program
based on U.S. data, phytotoxicity to non-target plants outside of the
application zone would be expected, since glyphosate is a broad spectrum
herbicide. Given the application method described by Department of State,
offsite exposure from spray drift is probable, as it would be under similar uses
in the U.S. This proposed use of glyphosate itself does not appear to pose a
significant direct risk to terrestrial or aquatic animals, although secondary
adverse effects from the temporary loss of habitat in the spray area could
occur. EPA would not expect any risk to birds and mammals, including livestock,
based on dietary exposure to the active ingredient glyphosate. Anticipated
effects to animals are based on an extrapolation of data related to North
American species. Glyphosate does not have a high potential to leach to ground
water or reach surface water as dissolved runoff but does have potential to
contaminate surface water as a result of residues suspended in runoff water. A
more refined assessment is difficult due to uncertainty regarding the exact
formulation of the spray solution.
As part of its consultation, EPA reviewed available scientific studies
and information on the human health and environmental effects of glyphosate and
the inert ingredients and on exposure pathways; conducted a literature search
for human health incidents related to glyphosate use in the U.S.; and summarized
use patterns for glyphosate in the U.S., including use sites, methods and rates
of application, and differing formulations. In addition, the Agency considered
information, provided by non-governmental sources, concerning adverse effects
reportedly connected to the eradication program.
Details of the Agency’s findings are provided in the attached document.
SECTION 1.
Description
of Glyphosate Use in the U.S. for Comparison to Use in Colombia for Coca
Eradication
INTRODUCTION: The Biological and Economic Analysis
Division (BEAD) within the Office of Pesticide Programs, Environmental
Protection Agency, has been asked to describe the use of glyphosate within the
United States with a more detailed description of its use in forestry sites so
that methods of use in the United States may be used as a basis for comparison
for coca eradication in Colombia (1).
SUMMARY: Glyphosate is the herbicide most widely used in
the United States1 (2). In agriculture this popularity is due, in
large part, to the development of crops that are highly tolerant to broadcast
applications of glyphosate which allows growers to use this non-selective
herbicide as their principal method of weed control in certain crops. Growers
have rapidly adopted glyphosate-based weed control programs with glyphosate
tolerant crops because they are simple and economical (3). In addition, due to
it’s unique properties, glyphosate is also widely used for non-agricultural weed
control situations including home lawns and gardens, forestry and other non-crop
sites where total vegetation control is desired.
1EPA’s (BEAD’s) biannual
pesticide sales and usage report estimates that in 1999, glyphosate was the most
used conventional pesticide in the U.S. (83 to 95 million pounds of glyphosate
applied) in all markets. It was second behind atrazine in the agricultural
market (67 to 73 million pounds of glyphosate applied); and second behind 2,4-D
in the non-agricultural market (16-22 million pounds of glyphosate applied). In
the agricultural market, data for 2000 and 2001 suggest that the usage of
glyphosate has increased to as much as 100 million pounds. Data is not yet
available for 2000 and 2001 for the non-agricultural market.
Glyphosate must be applied to the target plant’s foliage to be effective.
Glyphosate is non-selective in action, controlling a wide variety of plants.
Once absorbed, it circulates to untreated portions of the plant; and it has no
residual activity after contact with soil. Glyphosate may be applied using
hand-held, ground-driven or aerial equipment; the choice of equipment is
determined by the site to be treated. Although higher rates of application are
allowed, actual rates per application in agricultural sites average less than
0.75 pounds of the active ingredient glyphosate per acre (Table One). For the
non-agricultural site, forestry, use is allowed at rates per application ranging
from 2 to 10 pounds per acre (2.2 to 11.2 kilograms of active ingredient/
hectare) of glyphosate in the form of the isopropylamine salt (6). This rate of
use may also be expressed as 1.5 to 7.5 pounds per acre of acid equivalent (pure
glyphosate; not a salt). A more detailed discussion of the use of glyphosate in
the U.S. follows.
USE OF GLYPHOSATE IN THE UNITED STATES: Products
containing glyphosate are registered with the U.S. Environmental Protection
Agency, which means they may legally be used within the United States if used in
accordance with label instructions.
Glyphosate may be used on over 400 crop and non-crop sites. The largest
agricultural use sites include soybeans, cotton and field corn. The following
table summarizes estimates the use of glyphosate in three primary agricultural
use sites.
Table One. 2000 Glyphosate Use in U.S. Agriculture: In Total and for the
Three Major Use Sites
Site |
Acres Grown (million acres) |
Base
Acres Treated (million acres)1 |
Percent of Crop Treated2 |
Total
Acres Treated (million acres)3 |
Pounds
Applied (million lbs ai) |
Avg. Number of Apps |
Avg. Application Rate (lbs ai/acre/app) |
All Ag. Sites |
– |
– |
– |
102.7 |
73.5 |
– |
– |
Corn |
73.8 |
6.6 |
9% |
7.3 |
4.4 |
1.1 |
0.59 |
Cotton |
14.4 |
8.1 |
56% |
13.8 |
9.5 |
1.7 |
0.67 |
Soybeans |
71.0 |
44.0 |
62% |
57.2 |
41.8 |
1.3 |
0.68 |
Source: USDA, National
Agricultural Statistics Service (NASS) 2000 field crop chemical use (May, 2001),
and EPA proprietary data.
1Base acres treated = acres treated 1
or more times with glyphosate.
2Percent of crop treated = base acres
treated with glyphosate divided by acres grown.
3Total acres treated = based acres
treated with glyphosate multiplied by the average number of applications of
glyphosate.
In addition to agricultural
use, EPA estimates that 16-22 million pounds of the technical grade active
ingredient were applied to non-agricultural sites in 1999 (this is the most
recent year for which adequate data are available). The estimate includes both
home owner and professional applications as well as use on forested lands (11).
Based on EPA data for 1999, an estimated 1-2 million pounds of glyphosate was
applied to forest acres, with more than 650,000 forest acres treated.
AGRICULTURAL SITES: In certain annual crops, glyphosate
may be applied before planting (preplant) to control existing weeds; often
replacing tillage as a weed control measure in "no-till" crop culture systems
designed for reducing soil erosion. However, most of the glyphosate currently
used in agricultural sites is used in a cropping system employing crop varieties
that have been developed to be resistant to glyphosate so that glyphosate may be
applied "over-the-top" of the resistant crop to kill susceptible weeds. The most
prevalent of these systems is the Round-up Ready Soybean® system. These soybeans,
which are highly tolerant to glyphosate, were marketed starting in 1996. Since
then this system has been widely and rapidly adopted; in 1990-1991, glyphosate
ranked 11th among conventional pesticides used in the U.S. with
annual use estimated to be 18.7 million pounds (4). In 2000, glyphosate was the
most widely used herbicide in soybeans; nearly 42 million pounds of glyphosate
were applied to soybeans alone (2) with over 60 percent of soybeans surveyed by
USDA’s National Agricultural Statistical Service treated with glyphosate (5).
Round-up®, a glyphosate product marketed for agricultural use is formulated with
a surfactant during manufacture to facilitate foliar absorption. The following
table (Table Two) summarizes the use rates specified in label instructions for
Roundup OriginalTM product herbicide concentrate (12) which contains
the isopropylamine salt of glyphosate for use in glyphosate-tolerant soybeans.
Table Two. Allowed Rate of
the Isopropylamine Salt of Glyphosate Per Application in Tolerant Soybeans
Maximum for Application Timing |
Quarts of Product/Acre |
Pounds of Active Ingredient/Acre |
Kilograms of Active Ingredient/Hectare |
For Entire Season |
8 |
8 |
9 |
Before Crop Emergence |
5 |
5 |
5.6 |
In Crop |
3 |
3 |
3.4 |
Up to Two Weeks Prior to Harvest |
1 |
1 |
1.1 |
NON-AGRICULTURAL USES
INCLUDING FORESTRY:
BEAD has been asked to describe the use of glyphosate in U.S. forestry sites
since that use most closely corresponds to the use of glyphosate in Colombia for
coca control. For simplicity this document only refers to Accord® which is
intended specifically for forestry use (6). This product contains the
isopropylamine salt of glyphosate (41.5%), and is labeled for non-agricultural
uses including Forestry Site Preparation and Utility Rights-of Way, Forestry
Site Conifer and Hardwood Release, and Wetland Sites in the U.S. Table Three
describes the rates at which it may be used. It is recommended for use in site
preparation prior to planting any tree species, including Christmas tree and
silvicultural nursery sites (7). Specific methods of application for forestry
uses include: aerial spraying; spraying from a truck, backpack or hand-held
sprayer; wipe application; frill treatment; cut stump treatment (7).
For forestry site
preparation it may be applied using either ground or aerial equipment at rates
from 2 to10 pounds glyphosate active ingredient per acre which is equivalent to
2.2-11.2 kilograms of active ingredient per hectare (Table Three). It may also
be applied using hand-held equipment. Product instructions specify that a non-ionic
surfactant be added to the spray mixture for all forestry uses at a rate of 0.5
to 1.5 percent by spray volume (2 to 6 quarts of surfactant per 100 gallons of
spray solution). It may also be combined with certain residual herbicides to
extend the period of weed control beyond that obtained with glyphosate alone.
The isopropylamine salt of
glyphosate may also be used in forestry conifer and hardwood release as a
directed spray or by using selective equipment. This product may also be used in
or around wetland sites generally at no more than 5 quarts of product per acre
(5 lbs isopropylamine salt of glyphosate per acre which is equal to 5.6 kg/ha)
using over-water broadcast application (5).
Table Three. Rate of
Isopropylamine Salt of Glyphosate Per Application For Certain Use Sites
|
Quarts of Product/Acre |
Pounds of Active Ingredient/Acre |
Kilograms of Active Ingredient/Hectare |
Forestry Site Preparation and Utility Rights-of Way |
2-10 |
2-10 |
2.2-11.2 |
Forestry Site Conifer and Hardwood Release |
2-10 |
2-10 |
2.2-11.2 |
Wetland Sites |
2-5 |
2-5 |
2.2-5.6 |
PROPERTIES OF GLYPHOSATE:
Glyphosate is a foliar-active herbicide; to exert herbicidal properties it must
enter the plant through foliage (or in some cases, the stem). Glyphosate applied
to foliage is absorbed by leaves and rapidly moves through the plant. It acts by
preventing the plant from producing an essential amino acid. This reduces the
production of protein in the plant, and inhibits plant growth.
Glyphosate has systemic
activity, meaning that it circulates through the plant’s vascular system;
affecting the entire plant, not just the treated foliage. Other foliar-active
herbicides, like paraquat for example, are contact herbicides; affecting only
the portion of the plant onto which they are applied. After treatment with a
contact herbicide, a plant may then regrow from untreated portions, often
necessitating re-treatment for complete control. The advantage to a systemic
herbicide is that if applied at an appropriate dose, it can kill an entire plant,
thus preventing regrowth from an untreated plant part such as a root.
Glyphosate has no residual
activity, once adsorbed to soil it quickly becomes unavailable to plants and no
longer has herbicidal activity. This means that a plant that would ordinarily be
susceptible to glyphosate can be planted shortly after an application of
glyphosate; this is common practice in U.S. agriculture. In contrast, some
herbicides have month-long or even year-long residual activity which limits the
plants that may be grown following their use.
Glyphosate is non-selective.
Some herbicides are selective in their action, controlling only grassy weeds in
a broadleaf crop like soybeans, for example. However, glyphosate exerts
herbicidal action on a variety of plants; it is active on grasses, herbaceous
plants including deep rooted perennial weeds, brush, some broadleaf trees and
shrubs, and some conifers. However, glyphosate does not control all broadleaf
woody plants. Plants vary in their susceptibility to glyphosate, so the
treatment of dose in important. Plants of certain species and older plants are
less susceptible to glyphosate Timing is critical for effectiveness on some
broadleaf woody plants and conifers.
FORMULATIONS OF
GLYPHOSATE:
Glyphosate and four salts of the parent glyphosate molecule are currently used
as active ingredients in registered pesticide products in the U.S.(9). These
products are registered with the U.S. EPA for use in the U.S. in many different
crop, non-crop, industrial and residential sites.
Table Four. Number of
Products and Sites for Different Formulations of Glyphosate
Active Ingredient |
Number of Products |
Number of Sites |
Glyphosate acid |
28 |
more than 250 |
Ethanolamine salt |
2 |
more than 200 |
Ammonium salt |
16 |
more than 300 |
Isopropylamine salt |
237 |
more than 400 |
Trimesium salt |
6 |
more than 100 |
Sesquisodium salt |
no currently active products |
no active sites |
GLYPHOSATE USED WITH
SURFACTANT FOR FOLIAR ABSORPTION: Since glyphosate is only effective if absorbed by plant
foliage, glyphosate is combined with a surfactant to facilitate its absorption.
Many herbicide concentrates, including glyphosate, are mixed with water before
application. Without a surfactant, the aqueous spray mixture is repelled by the
plant’s waxy cuticle layer ("beads up"), and quickly runs off the plant’s
surface, preventing absorption.
Surfactants are commonly
used as wetting agents with herbicides and in other products such as laundry and
dishwashing detergent. Non-ionic surfactants, which are comprised of alcohols or
fatty acids and considered an all-purpose surfactant are commonly used with
glyphosate-containing products. Surfactants are frequently added during
manufacture of the herbicide concentrate. If not, a non-ionic surfactant is
generally mixed with the herbicide and water before spraying to enable the
liquid to make better contact with the waxy cuticle of the plant. These
glyphosate products, which are formulated without a surfactant, are considered
"non-loaded" (10).
A short description of
international usage of glyphosate, including Colombia, appears after the
following references to the above discussion.
REFERENCES:
(1) Description of Use of
Glyphosate in Coca Eradication in Colombia in attachment to a letter from
Secretary of State Colin Powell to Environmental Protection Agency Administrator
Governor Christine Whitman.
(2) Donaldson, D., T. Kiely,
and A. Grube. Pesticide Industry Sales and Usage, 1998 and 1999 Market Estimates.
June 2002. Biological and Economic Analysis Division, Office of Pesticide
Programs, U.S. Environmental Protection Agency.
(3) Gianessi, L.P., Silvers,
C., Sankula, S., and Carpenter, J. Plant Biotechnology: Current and Potential
Impact for Improving Pest Management in U.S. Agriculture - An Analysis of 40
Case Studies. June 2002. National Center for Food and Agricultural Policy.
Available on-line at http://www.ncfap.org.
(4) Glyphosate -
Reregistration Eligibility Decision. United States Environmental Protection
Agency. September 1993.
(5) Agricultural Chemical
Usage - 2000 Field Crops Summary. May 2001. United States Department of
Agriculture. National Agricultural Statistics Service.
(6) Accord® Herbicide
Specimen Label. Available on-line from CDMS.
(7) Pesticide Fact Sheet.
Prepared for the U.S. Department of Agriculture, Forest Service. Available on-line
at
infoventures.com/e-hlth/pesticide/glyphos.html
(8) D. Lantagne., M.
Koelling, and D. Dickman. Effective Herbicide Use in Christmas Tree Plantations.
Michigan State University Extension.
(9) U.S. Environmental
Protection Agency, Office of Pesticide Programs. Search of the Reference Files
System dated June 11, 2002.
(10)Miller, P., and P.
Westra. Crop Series: Production. Colorado State University. Available on-line @
http://www.colostate.edu/depts/ipm/pdf/00559.pdf
(11) EPA Proprietary
Information
(12) Roundup Original
HerbicideTM Supplemental Labeling for Postemergence Applications to
Soybeans with Roundup Ready® Gene. Available online from CDMS.
BEAD was asked to report on
the use of glyphosate in forestry sites since it seemed similar to the use
pattern for coca eradication. However, it is not clear how closely this use
approximates that for coca eradication. Glyphosate is typically applied to
forestry sites using helicopters at air speeds of 50-70 knots (about 60-80 miles
per hour). Application to forestry sites by fixed wing aircraft, if practiced at
all, is extremely rare (1). The recommended rate of application for pine release
(conifer release) is 1.5 to 2 pounds active ingredient per acre.
Aerial application to other
sites comprises less than one percent of the total amount of glyphosate applied
in the United States (3).
In addition to surfactants,
drift control agents may be added to the spray mixture for forestry uses in an
effort to prevent drift to off target sites. BEAD has not investigated the
prevalence of use or the effectiveness of these products.
BEAD estimates total global
use of glyphosate to be between 350 and 360 million pounds of glyphosate per
year. Annual use in the United States is approaches 100 million pounds of active
ingredient and an estimated 250 to 260 million pounds of glyphosate is used
outside of the United States. Use of glyphosate in Colombia accounts for between
four and five million pounds of this use. Primary sites in Colombia include
coffee, bananas, pasture-land and rice (3).
REFERENCES:
(1) Personal communication
between Virginia Werling, United States Environmental Protection Agency and John
Taylor, United States Forest Service on August 9, 2002.
(2) Hamilton, R.A. "2002
North Carolina Agricultural Chemicals Manual - Chemical Weed Control In Forest
Stands" Extension Forest Resources Department, North Carolina State University.
Available on-line at http://ipmwww.ncsu.edu/agchem/chptr8/821.pdf
(3) United States
Environmental Protection Agency Proprietary Data.
SECTION 2. Human Health Risk Assessment for the Use of Glyphosate
Herbicide as Part of the Aerial Eradication Program of Coca in Colombia, S.A.
I INTRODUCTION
The Department of State has
requested that the US Environmental Protection Agency (EPA), Office of Pesticide
Programs (OPP) provide a human health risk assessment for the aerial coca
eradication in Colombia. The Department of State (DoS) has requested that the
risk assessment address whether or not the aerial eradication program in
Colombia is being carried out in accordance with regulatory controls required by
the EPA as labeled for use in the United States, and the chemicals used, in the
manner in which they are being applied, do not pose unreasonable risks or
adverse effects to humans and or the environment. According to information
provided by DoS, the eradication program, includes the use of a spray mixture of
a glyphosate containing pesticide product, an adjuvant (Cosmo-Flux 411F) and
water. The glyphosate tank mixture is applied in an over the top aerial foliar
application in certain provinces within Colombia. To facilitate the request, the
DoS met with members of OPP on April 18 and sent a written request, dated May 8,
2002, with documentation on the coca eradication program, including a
description of the pesticide spray mixture components, application methods,
target site identification, and potential exposures. DoS also supplied EPA with
incident reports for aerial eradication of illicit poppy in Colombia.
The Field and External
Affairs Division (FEAD) of OPP, which has the responsibility of managing the EPA’s
role of providing technical information and assistance to DoS for this program,
forwarded the DoS request to Health Effects Division (HED), the Environmental
Fate and Effects Division (EFED), and the Biological and Economics Assessment
Division (BEAD) for scientific assessments. The HED of OPP is charged with
estimating the risk to human health from exposure to pesticides. Registration
Action Branch 1 (RAB1), Reregistration Branch 1 (RRB1) and the Chemistry and
Exposure Branch (CEB) of HED as a team have performed the assessment requested
by the Department of State and have evaluated the potential hazard, exposure,
and risk to human health from the U.S. supported coca eradication program
Colombia.
A summary of the findings
and an assessment of human risk resulting from the use of glyphosate in Colombia
to eradicate coca is provided in this document.
Unless otherwise specified,
all information pertaining to the U.S. supported coca eradication program in
Colombia was provided to the Agency from two sources: (1) Department of State (DoS)
Presentation, DoS Coca Eradication Program, 4/18/02, (2) DoS document entitled
Chemicals Used for the Aerial Eradication of Illicit Coca in Colombia and
Conditions of Application.
II EXECUTIVE SUMMARY
USE PATTERN
According to the State
Department, the glyphosate tank mixture is applied as an over the top aerial
foliar application to coca in certain provinces within Colombia. The tank
mixture sprayed for eradication of coca in Colombia contains 55% water, 44% of
glyphosate herbicide product, and 1% adjuvant (Cosmo-Flux 411F). Up to two
applications of the glyphosate tank mixture are sprayed over coca crops at a
maximum of 1.25 gallons of product/Acre. In order to assess the hazard of what
was sprayed in Colombia, components of the mixture were evaluated separately.
HAZARD ASSESSMENT
The Cosmo-Flux 411F
adjuvant used in the glyphosate tank mix is produced by a Colombian company and
is not sold in the U.S. All ingredients identified as contained in this product
are substances that are not highly toxic by oral or dermal routes. They may
cause mild eye and skin irritation. Cosmo-Flux 411F consists mainly of (information
not included as it may be entitled to confidential treatment) with a
nonionic surfactant blend primarily composed of (information not included as
it may be entitled to confidential treatment).
The available hazard data
base on experimental animals indicates that the Glyphosate technical
grade active ingredient (TGAI) has low acute toxicity via the oral and dermal
routes. It is a mild eye irritant and a slight dermal irritant. It is not a
dermal sensitizer. The requirement for an acute inhalation study was waived
since no respiratory or systemic toxicity was seen following subchronic
inhalation exposure in rats. In the subchronic and chronic oral toxicity studies
(1-year dog, 24-month mouse, 2-year chronic/carcinogenicity rat, and 2-generation
rat reproduction), systemic toxicity manifested most commonly as clinical signs,
decreases in body weight and/or body weight gain, decreased food consumption,
and/or liver and kidney toxicity at doses equal to or above the limit dose (1000
mg/kg/day). No dermal or systemic toxicity was seen following repeated dermal
exposures. There was no quantitative or qualitative evidence for increased
susceptibility in fetuses following in utero exposure to rats and rabbits
in developmental toxicity studies or following pre/post-natal exposure to rats
in the 2 generation reproductive toxicity study in rats. Effects in the
offspring were observed only at or above treatment levels which resulted in
evidence of appreciable parental toxicity.
The Food Quality Protection
Act (FQPA) Safety Factor Committee (SFC) concluded that the safety factor, to
protect infants and children, of 10x be removed (reduced to 1x). The Hazard
Identification Assessment Review Committee (HIARC) met on March 26, 1998 and,
again, on November 20, 2001. The most recent report of the HIARC for glyphosate
has the complete assessment of the endpoints selected for dietary exposure and
residential/occupational exposure. No endpoints were selected for the acute
Reference Dose (RfD) since no hazard attributed to a single dose was identified
from the oral toxicity studies, and there are no concerns for developmental or
reproductive toxicity. In addition, the HIARC did not identify endpoints of
concern for dermal and inhalation exposures for any exposure period (short term
1-30 days, intermediate term- 1 to 6 months, or long term- 6 months to lifetime)
since no hazard was identified due to the low toxicity of glyphosate. HIARC did
identify an incidental oral endpoint for short- and intermediate-term exposure.
The chronic dietary RfD of 1.75 mg/kg/day was based on diarrhea, nasal discharge,
and mortality in a rabbit developmental toxicity study. Glyphosate was not
mutagenic in a full battery of assays. Based on the lack of evidence for
carcinogenicity in two acceptable studies in mice and rats, glyphosate is
classified as a "Group E" chemical (no evidence of carcinogenicity to humans).
EXPOSURE
An exposure and risk
assessment is required for an active ingredient if: (1) certain toxicological
criteria are triggered and (2) there is potential for exposure. Upon review and
analysis of the hazard database in total, the Agency’s HIARC did not identify a
hazard of concern for acute dietary, dermal, or inhalation exposures. Therefore,
quantitative estimates of risk for these exposure durations have not been
conducted (TXR No. 0050428, W. Dykstra, 22-JAN-2002).
Acute dietary exposure
is possible for persons consuming livestock or food crops which have been
inadvertently sprayed as a result of the aerial eradication program in Colombia.
However, since glyphosate is a contact herbicide that systemically kills plants
after absorption through leaves, dietary exposure due to consumption of treated
crops is expected to be limited. In addition, since an acute dietary endpoint
was not identified in the hazard database, no significant risk due to acute
dietary food exposure to glyphosate residues is expected. Based on the fact that
a coca field is sprayed no more than twice to eradicate the crop, no chronic
food exposure is expected.
Handler (e.g.,
individuals mixing the concentrated formulated product to prepare the tank mix
and loading the tank mix in the aircraft) exposure is anticipated for short-term (1-30
days) and, possibly intermediate-term (1-6 months) durations based on the
frequency of application and duration of the spray program.
Based on the use pattern
described by the DoS, short-term dermal post-application exposures are
expected for persons pruning, or leaf pulling treated coca plants immediately
after spray events. In cases such as glyphosate, where the vapor pressure is
negligible, OPP experience with post-application data suggests that inhalation
exposure is minimal and OPP does not quantitatively assess post-application
inhalation exposure. Intermediate- and long-term post-application exposures are
not expected due in part to the fact that a coca field is sprayed twice to
eradicate the crop. Additionally, glyphosate is a translocated herbicide which
is rainfast within 48 hours after spraying. Therefore, potential exposure to
dislodgeable residues of glyphosate after 48 hours is expected to be minimal.
DoS states that pilots are
instructed not to spray fields where people are present. Therefore, incidental
oral exposure (hand-to-mouth) resulting from individuals being directly sprayed
by glyphosate was not assessed. Non-dietary incidental oral exposure was not
quantitatively assessed for the use of glyphosate in Colombia.
There is potential for
exposure to bystanders in areas near those targeted for spraying. However, the
technology and other safeguards described by DoS as being used in this program
are consistent with common approaches in the United States for reducing spray
drift. Therefore, it is likely that drift is minimized in this program if
all procedures are adhered to and operational equipment is in working order.
From the review of Colombian
glyphosate product human incident reports for poppy eradication, it
should be emphasized that the overwhelming majority (95%) of the illnesses
reported are likely background incidents unrelated to the spraying of herbicide
to poppy. The remaining 5% increase could be due to a variety of causes and do
not support a conclusion that the spraying of the glyphosate tank mixture was
responsible for these complaints. Furthermore, the individual with the highest
potential for exposure would be the mixer loader. They are handling the
concentrated glyphosate product and the tank mix. The incidence data that has
been submitted to the Agency by DoS, does not include any incident reports for
those individuals. There are data to suggest that the poppy spray eradication
program could have resulted in minor skin, eye, or respiratory irritation, and
perhaps headache or other minor symptoms. However, the detailed information on
timing of application, history of exposure, and medical documentation of
symptoms related to exposure to glyphosate tank mix were not available. Given
the limited amount of documentation, none of the data in the report from
Colombia provide a compelling case that the spraying of the glyphosate mixture
has been a significant cause of illness in the region studied. Prospective
tracking of reports of health complaints, documenting times of exposure and
onset of symptoms, are recommended during future spray operations to evaluate
any potential health effects and ameliorate or prevent their occurrence.
A direct comparison of the
epidemiological data in Colombia (which is from aerial application to poppy) to
the conditions of use, (as presented at the April 18, 2002 briefing for aerial
application to coca by DoS to OPP risk assessors), would be limited. The
briefing and the materials provided did not address the conditions of use for
poppy. Nor was the Agency provided any human incident data for the coca
eradication program. Subsequent to the April 18 briefing HED received an e-mail
communication from OPP/Field and External Affairs Division, stating that DoS
informed EPA that the application rate for poppy was lower than that for coca.
According to the DoS, the use pattern of the glyphosate mixture on poppy differs
from the use on coca. Other details of the differences between the two spray
programs have not been supplied to the Agency. Specifically, the Agency has no
information as to the exact makeup of the tank mixture sprayed on poppy, or
whether the same glyphosate product and adjuvants used in the coca eradication
program were used in the poppy eradication program. The Agency also has
questions as to the geographical area differences, the frequency of repeated
applications, and the size of the area treated on each spray mission. Therefore,
generalized conclusions drawn from human incident data as a result of
application to opium poppy, in comparison to conditions of use for the coca
eradication program should be made with caution.
The glyphosate formulated
product used in the coca eradication program in Colombia contains the active
ingredient glyphosate, a surfactant blend, and water. The acute toxicity test of
the glyphosate technical is classified as toxicity category III for
primary eye irritation and toxicity category IV for acute dermal and oral
toxicity, and skin irritation. It is not a dermal sensitizer. However, the
surfactant used in the formulated product reportedly can cause severe
skin irritation and be corrosive to the eyes, as would be expected for many
surfactants. The label for the formulated product used in the coca
eradication program in Colombia includes the "Danger" signal word. These
findings suggest that any of the reports of toxicity to the eye may be due to
the surfactant, not glyphosate per se. The product has been determined to be
toxicity category I for eye irritation, causing irreversible eye damage.
There may be a correlation
between the ocular toxicity caused by the surfactant and reported incidents of
ocular effects. This is supported by data obtained from the California Pesticide
Illness Surveillance Program (1982-2000). In 1992 the glyphosate product was
reformulated in the US to reduce the amount of surfactant which posed a hazard
to the eye. From 1982 through 1991, there were 221 illnesses involving the eye
or 22.1 cases per year. From 1994 (allowing 2 years for the product to be
introduced into trade and widespread use) through 2000, there were 65 illnesses
involving the eye or 9.3 cases per year, a decline of 58%. Therefore, these data
support the finding that use of the reformulated glyphosate product since 1992,
has resulted in a significant drop in illnesses. Overall, the total illnesses
due to glyphosate declined by 39% from the 1982-1991 time period to the
1994-2000 time period, largely due to reduction in eye injuries.
The greatest potential for
eye exposure is expected for workers mixing and loading the concentrated
glyphosate product. There is also the potential for eye exposure as a result of
entering treated fields after treatment to perform pruning or harvesting
activities.
During an April 18 briefing,
the Department of State agreed to supply the Agency with a full battery of the
six acute toxicity tests on the tank mix. To date this information has not been
received. Until such information is supplied to the Agency, EPA cannot evaluate
the potential ocular or dermal toxicity resulting from direct contact with the
tank mixture. Therefore, due to the acute eye irritation caused by the
concentrated glyphosate formulated product and the lack of acute toxicity data
on the tank mixture, the Agency recommends that DoS consider using an
alternative glyphosate product (with lower potential for acute toxicity) in
future coca and/or poppy aerial eradication programs.
III BACKGROUND
EPA regulates pesticides
under two statutes, the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)
and the Federal Food, Drug, and Cosmetic Act (FFDCA). FIFRA provides the
authority to register and review pesticides as well as the authority to suspend
and cancel if use poses unreasonable risks. FFDCA provides authority to set
maximum residue levels (tolerances) for pesticides used in or on foods or animal
feeds.
Section 3 of FIFRA provides
authority to register (license for sale and distribution) pesticide products.
The label of the pesticide product specifies the use (pest and crop/site),
amount of product to be applied, frequency, timing of use, restrictions, storage
and disposal practices and precautionary statements. The active ingredient in a
pesticide product is the "ingredient which will prevent, destroy, repel, or
mitigate any pest." The inert or other ingredient(s) in a pesticide product is "an
ingredient which is not active." The registrant must provide data for the Agency
to assess potential environmental and human health risks. The data required to
make a safety finding are dependent on the intended use, e.g., food use vs non-food
use. The data requirements for pesticides may be found in 40 CFR Part 158. For
human health risk assessment, data is required to permit characterization of
hazard and exposure.
Data requirements on the
chemical identity and composition of the formulated pesticide product, may be
found in 40 CFR 158.150. The list of ingredients for a pesticide product and the
percent of each ingredient in the formulation are contained in the confidential
statement of formula (CSF). The CSF is FIFRA confidential business information (CBI)
and is entitled to treatment as trade secret or proprietary information. Agency
risk assessments do not typically contain this information.
In finalizing the current document, FEAD and HED consulted with OPP’s
Information Resources and Services Division/Public Information and Records
Integrity Branch regarding CBI. It was determined that the document did contain
some CBI and therefore, some sections have been adapted.
Residue chemistry data
required as per 40 CFR 158.240 support the ability of the Agency to estimate the
amount of pesticide that will result in food as a result of application of the
pesticide according to the product labels directions for use. The magnitude of
the residue studies for crop field trials use the typical end use product as the
test material. The livestock feeding studies are required whenever a pesticide
residue will be present in livestock feed. The livestock feeding studies
evaluate the magnitude of the resulting pesticide residue in meat, milk, poultry,
and eggs. The studies are conducted with the technical grade of the active
ingredient or the plant metabolites Residue chemistry data are also required to
identify any potential metabolites of concern. These data are used to determine
the tolerances for the parent and or metabolites. Additional data is required on
environmental fate, degradation, metabolism, and dissipation.
Hazard data required for
human health risk assessment are provided in 40 CFR 158.340. The use of the
active ingredient (i.e., food use or non-food use) will determine what studies
are required. The acute toxicity data on the technical grade of the active
ingredient are used for classification and precautionary labeling for protective
clothing requirements, and worker reentry intervals. The only studies that are
required to be conducted on the manufacturing use product or end use product are
the acute toxicity studies. The remaining toxicology studies (e.g.,
developmental toxicity, reproduction, subchronic, chronic feeding, or
carcinogenicity studies) require that the test substance is the technical grade
of the active ingredient. Subchronic toxicity studies provide data on potential
target organ toxicity and are also used to select dose levels for long term or
chronic toxicity studies. Chronic toxicity or carcinogenicity studies are
conducted for food use chemicals to determine potential effects following
prolonged or repeated exposure that may have a latency period for expression.
The test animals are exposed orally for a significant portion of their life span.
Developmental toxicity studies are required in two species (usually the rat and
rabbit) for food use chemicals. They are conducted to detect alterations in the
normal development of fetuses following in utero exposure. The 2-generation
rat reproductive toxicity study is required to assess potential alterations in
gonadal function, estrus cycles, mating, conception, birth, lactation, weaning,
as well as growth and development of offspring. The Agency also requires a
battery of mutagenicity studies to assess the potential induction of changes in
the genetic material of cells. The above studies are required for food use
active ingredients. In general, less data is required for non-food use active
ingredients and inerts unless a concern has triggered additional testing.
The Agency conducts separate
risk assessments for all pesticide active ingredients and has conducted risk
assessments for some inerts. The remaining inerts are cleared by the Agency. It
should be understood that whenever the inert ingredient was cleared, whenever
the tolerance exemption was established, the inert met the standards of the
time. Inert ingredients, also known as "other ingredients," are the carrier for
the active ingredients which allow the product to deliver the active ingredient
at a specific rate and ensure proper distribution during application. Currently
there are over 3200 inert ingredients cleared by EPA for use in various domestic
pesticides products. There are two major classifications: non-food use (such as
lawn care products and bathroom cleaners), and food-use, which require an
exemption from the requirement of a tolerance and can also be used in non-food
products.
The Agency has a newly
developed methodology for evaluating low or low/moderate toxicity chemical
substances by way of a screening process that incorporates elements of a tiered
approach (US EPA, May 2002). Use of this process will permit the Agency to clear
more chemicals of low to moderate toxicity for use in pesticide products. The
Agency is aware that some chemicals may be used as inert ingredients in some
formulations and as active ingredients in other formulations. EPA believes this
methodology is appropriate for evaluating some low toxicity chemicals regardless
of whether they are categorized as active or inert ingredients. The new process
will permit the Agency to be able to conduct more in-depth evaluations of other
ingredients that are of potentially higher toxicity. Chemicals of higher
toxicity that can not be appropriately addressed in the lower tiers would be
evaluated in a manner substantially similar to that of an active ingredient.
Later as the Agency begins to review chemical-specific or surrogate information
in the open literature, the preliminary tier determination may be revised (US
EPA, May 2002).
Inert ingredients that are
exempt from tolerance are listed in 40 CFR 180.1001 (c). The inert ingredients
in the glyphosate formulation have been approved by the Agency. The components
of the adjuvant (Cosmo-Flux 411F), that DoS indicates have been sprayed on coca
plants in Colombia have also been determined to be approved for use on food by
the Agency.
The two federal statutes for
regulating pesticides in the US give EPA limited authority to regulate the sale,
or use of adjuvants in the US. EPA only has authority to regulate the pesticide
product itself. For example, if a chemical in an adjuvant was intentionally
included in the formulation of a pesticide product, the chemical would be
regarded as an inert ingredient. In the US as with all countries, adjuvants are
commonly used and added to pesticides as wetting agents, spreaders. emulsifiers,
antifoamers, penetrants, or for other purposes. These may contain surfactants,
solvents, or other types of chemicals to achieve the desired purpose.
An adjuvant is a subsidiary
ingredient or additive product added to a pesticide in a mixture that aids the
effectiveness of the primary or active ingredient. Adjuvants are most commonly
added to tank mixes of pesticide products prior to application to the site to be
treated. Adjuvants are not directly subject to FIFRA registration if no
pesticidal claims are made. Pesticide manufacturers choose whether or not to
address on their product labels the use of adjuvants with their product(s).
However, when added to a tank mix for application to a food or feed crop/site,
the individual components must be cleared under FFDCA. While adjuvant products
are not registered on the federal level, they are subject to registration under
some state laws. The states of Washington and California are two states that
register adjuvants. The adjuvant (Cosmo-Flux 411F) used in the glyphosate tank
mix is produced by a Colombian company and is not sold in the U.S. The
Department of State has agreed to provide the Agency with acute toxicity data
performed on the actual tank mix that has been sprayed in Colombia.
IV HISTORICAL REGULATORY INFORMATION
The glyphosate product used
in Colombia according to the Department of State was registered in the US in
April 1974. From 1974-1992 the product was registered for use on a number of
agricultural and nonagricultural sites. The product had a "Warning" signal word
for eye irritation. In 1992, the registrant submitted an eye irritation study
that was categorized as Toxicity Category I and required a "Danger" signal word.
The registrant decided that they did not want to market a glyphosate product
with a "Danger" signal word. Around July 1992, the registrant registered a
reformulated glyphosate product for use in the United States that had the
percentage of surfactant reduced to a level that produced Toxicity Category II
eye irritation. The original product was re-labeled - "Not for use in the United
States". Because the Agency never rescinded the registrations for the use sites
that were on the initial label before it was changed, the product technically
remains registered for use on numerous agricultural and nonagricultural sites
although it is not currently labeled for these uses. In November 2001, the
Company submitted a label for the original product for ground and aerial
application to control undesirable vegetation in nonagricultural sites. This
registration was intended to register a glyphosate product that corresponds to
the product being used in Colombia. In February 2002 the product name was
changed and the maximum application rate was reduced as per the request of the
registrant.
V HAZARD IDENTIFICATION
Hazard identification is the
first step in the risk assessment process. The objective is to qualitatively
characterize the inherent toxicity of a chemical. Scientific data are evaluated
to establish a causal relationship between the occurrence of adverse health
effects and exposure to a chemical. Because high quality controlled toxicology
studies on humans are frequently unavailable, regulatory scientists rely on
animal data to estimate hazard to support regulatory decision making. Prior to
and subsequent to initial registration, the Agency has required the registrants
of glyphosate products to submit appropriate studies according to contemporary
study requirements and testing protocol requirements.
Glyphosate
The available hazard data
base on experimental animals indicates that glyphosate has low acute toxicity
via the oral and dermal routes with LD50s > 5000 mg/kg. It is a mild
eye irritant and a slight dermal irritant. It is not a dermal sensitizer. The
requirement for an acute inhalation study was waived since no respiratory or
systemic toxicity was seen following subchronic inhalation exposure in rats. In
the subchronic and chronic oral toxicity studies (1-year dog, 24-month mouse, 2-year
chronic/carcinogenicity rat, and 2-generation rat reproduction), systemic
toxicity manifested most commonly as clinical signs, decreases in body weight
and/or body weight gain, decreased food consumption, and/or liver and kidney
toxicity at doses equal to or above the limit dose (1000 mg/kg/day). No dermal
or systemic toxicity was seen following repeated dermal exposures. There was no
quantitative or qualitative evidence for increased susceptibility in fetuses
following in utero exposure to rats and rabbits in developmental toxicity
studies or following pre/post-natal exposure to rats in the 2-generation
reproductive toxicity study in rats. Effects in the offspring were observed only
at or above treatment levels which resulted in evidence of appreciable parental
toxicity. Glyphosate was not mutagenic in a full battery of assays. Based on the
lack of evidence for carcinogenicity in two acceptable studies in mice and rats,
glyphosate is classified as a "Group E" chemical (no evidence of carcinogenicity
to humans).
Components of the
Glyphosate Product
1. Polyoxyethylene alkylamine (POEA).
POEA is a compound that is used as a surfactant with many glyphosate
formulations. In a safety evaluation and risk assessment of glyphosate, the
Roundup formulation and the surfactant POEA, Williams et al. (2000)
reported that POEA can cause severe skin irritation and be corrosive to the eyes.
In subchronic oral studies, POEA was mainly a gastrointestinal irritant in rats
at high doses (~ 100 mg/kg/day) and in dogs at lower doses (30 mg/kg/day). In a
developmental toxicity study in rats, POEA did not cause any developmental
effects up to 300 mg/kg/day, but did induce maternal toxicity at 100 and 300 mg/kg/day
(Farmer et al., 2000). The concentrated formulated Roundup product can
also be strongly irritating to the eyes and slightly irritating to the skin (Williams
et al., 2000).
2. (information not included as
it may be entitled to confidential treatment) are substances that are
not highly toxic by oral or dermal routes and are not irritating to the skin.
They may cause mild, transient eye irritation. Many (information not included
as it may be entitled to confidential treatment) are known not to be
sensitizers (study citation not included as it may be entitled to
confidential treatment). The molecular weight of a (information not
included as it may be entitled to confidential treatment) determines its
biological properties, and, thus, its toxicity. The lower molecular weight (information
not included as it may be entitled to confidential treatment) tend to be
more toxic than the higher-weighted (information not included as it may be
entitled to confidential treatment) and are absorbed by the digestive tract
and excreted in the urine and feces, while the higher molecular weight (information
not included as it may be entitled to confidential treatment) are absorbed
more slowly or not at all (study citation not included as it may be entitled
to confidential treatment). (information not included as it may be
entitled to confidential treatment) have low acute and chronic toxicity in
animal studies. No significant adverse effects have been noted in inhalation
toxicology studies, carcinogen testing, or mutagen assays. High oral doses have
resulted in toxic effects to the kidneys and loose feces (study citation not
included as it may be entitled to confidential treatment). Topical dermal
application of (information not included as it may be entitled to
confidential treatment) to burn patients with injured skin has resulted in
toxicity (study citation not included as it may be entitled to confidential
treatment).
Cosmo - Flux 411F (Adjuvant)
The Cosmo-Flux 411F adjuvant
product used in the glyphosate tank mix is produced by a Colombian company and
is not sold in the U.S. The Agency is not in possession of toxicity data from
direct dosing of test animals with Cosmo-Flux 411F. However, the Agency has made
a hazard assessment based on the toxicity of the individual components. As
stated above, sale or use of spray adjuvant products in the U.S. are generally
not regulated by EPA. However, the DoS has provided the EPA with a copy of this
product’s label and a description of the product ingredients. To be able to
provide an opinion on hazard characterization of the Cosmo-flux ingredients, the
EPA relied on available technical information from various sources. Cosmo-Flux
411F consists mainly of (information not included as it may be entitled to
confidential treatment) with a nonionic surfactant blend primarily composed
of (information not included as it may be entitled to confidential treatment).
All ingredients of this product are substances that are not highly toxic by oral
or dermal routes. They may cause mild eye and skin irritation. All components of
the adjuvant have been approved for use in/on food by EPA (40 CFR 180.1001,
Letter from R.Forrest/EPA, to R.Woolfolk/DoS, 7/30/2001).
Components of Cosmflux
1. (information not included as it may
be entitled to confidential treatment). The (information not included as it may be entitled to
confidential treatment) can cause dermal and ocular irritation and, in high
doses orally, can cause significant toxicity. However, small amounts are not a
concern and these substances have been approved as food additives by the FDA and
are exempt from tolerances by EPA on certain commodities.
2. (information not included as it may
be entitled to confidential treatment). The other major component of Cosmo-Flux 411F, (information
not included as it may be entitled to confidential treatment), is not
considered highly toxic. It may cause mild eye and skin irritation. The
corresponding (information not included as it may be entitled to confidential
treatment), has low subacute, subchronic and chronic oral toxicity and is
used as a direct food additive and a component in cosmetics. The higher
molecular weight (information not included as it may be entitled to
confidential treatment) is less likely to be absorbed orally or dermally and
most likely of less toxicological concern. The other minor components, are not
known to be highly toxic compounds and would not be of toxicological concern at
the concentrations and conditions in which they are used.
VI DOSE RESPONSE ASSESSMENT
Dose response analysis is
the second step in the risk assessment process i.e.; characterization of the
quantitative relationship between exposure (dose) and response based on studies
in which adverse health effects have been observed. The objective is to identify
endpoints of concern which correspond to the route and duration of exposure
based on the exposure patterns.
HED selects doses and
endpoints (effects of concern) for risk assessment via an internal peer review
process. HED uses a standing Committee - the Hazard Identification Assessment
Review Committee (HIARC), to consider the available hazard data (studies
required to be submitted by registrants in 40 CFR part 158 and open peer
reviewed literature) to identify endpoints for use in risk assessment.
Ideally, each safety study
identifies a dose level that does not produce a biologically or statistically
significant increased incidence of an adverse effect or no observable adverse
effect level (NOAEL). The threshold dose is the smallest dose required to
produce a detectable effect. Below this dose, there is no detectable response.
Glyphosate
On March 26, 1998 and,
again, on November 20, 2001 the HED HIARC met to examine the hazard
data base and identify dietary endpoints for Females 13-50 years old, as well as
the General Population, the chronic reference dose. The HIARC also considered
toxicological endpoints for incidental oral exposure (on 20-NOV-01) appropriate
in residential exposure risk assessments.
The most recent report of
the HIARC for glyphosate has the complete assessment of the endpoints selected
for dietary and residential/occupational exposures (W. Dykstra, 01/22/02; TXR#
0050428). OPP calculates acute (24 hour or single day) and chronic (continuous
lifetime exposure) RfDs for the purposes of calculating dietary risk for food
and drinking water. The RfD is calculated by dividing the appropriate no
observed adverse effect level by a ten fold factor for interspecies variability
("average" human sensitivities might be up to 10 times that of lab animals) and
a ten fold factor for intraspecies variability (i.e., some individuals within a
population might be 10 times more sensitive than the "average" person).
For glyphosate, no endpoints
were selected for the acute RfD since no hazard attributed to a single dose was
identified from the oral toxicity studies, and there are no specific concerns
for toxic effects on the developing fetus or infants and children. In addition,
the HIARC did not identify endpoints of concern for dermal and inhalation
exposures for any exposure period (short term- 1 to30 days, intermediate term- 1
to 6 months, or long term- 6 months to lifetime) since no hazard was identified
due to the low toxicity of glyphosate (TXR No. 0050428, W. Dykstra, 22-JAN-2002).
The chronic dietary RfD of 1.75 mg/kg/day was based on diarrhea, nasal discharge,
and mortality in a rabbit developmental toxicity study. A summary of doses and
toxicological endpoints selected for various relevant exposure scenarios are
summarized in Table 1.
Table 1. Glyphosate
Endpoint Selection Table
EXPOSURE |
DOSE |
ENDPOINT |
STUDY |
Acute
Dietary |
An effect of concern attributable to a single dose was not identified from the oral toxicity studies; there are no concerns for developmental or reproductive toxicity. |
||
Chronic Dietary (continuous lifetime exposure) |
NOAEL = 175 uncertainty factor (UF) = 100 |
Maternal toxicity based on clinical signs (diarrhea and nasal discharge)resulting in mortality of some dams at 350 mg/kg/day |
Developmental toxicity -Rabbit |
Chronic RfD = 2.0 mg/kg/day |
|||
Incidental Oral, Short- (1-30 days), and Intermediate-(1-6 months) Term |
NOAEL= 175 |
Maternal toxicity based on clinical signs (diarrhea and nasal discharge)resulting in mortality of some dams at 350 mg/kg/day |
Developmental toxicity -Rabbit |
Dermal, Short-, Intermediate-and Long-Term |
No hazard was identified, therefore quantification of dermal risk is not required. No systemic toxicity was seen at the Limit Dose (1000 mg/kg/day) following repeated dermal applications to New Zealand White rabbits. |
||
Inhalation, Short-, Intermediate-, and Long-Term |
Quantification of inhalation risk is not required because 1) no hazard was identified in the 28 day inhalation toxicity study in rats - NOAEL = 0.36 mg/L (highest dose tested (HDT)); lowest observable adverse effect level (LOAEL) not established based on 6 hours/day, 5 days/week for 4 weeks and 2) due to the physical characteristics of the technical (wetcake), exposure to high levels of the active ingredient is unlikely via the inhalation route, so there was no purpose to test at higher doses. |
Glyphosate Food Quality
Protection Act (FQPA) Considerations
On August 3, 1996 the FQPA
amended FIFRA and FFDCA. Section 408(b)(2)(C) of the Federal Food, Drug, and
Cosmetic Act addresses exposure of infants and children. Under this provision
EPA must apply the default 10X safety factor when establishing, modifying,
leaving in effect or revoking a tolerance or exemption for a pesticide chemical
residue, unless the EPA concludes, based on reliable data, that a different
safety factor would protect the safety of infants and children. Risk assessors,
therefore presume that the default 10X safety factor applies and should only
recommend a different factor, based on an individualized assessment, when
reliable data shows that such different factor is safe for infants and children
that it does not rely on a default value or presumption in making decisions
under Section 408 where reliable data are available that support an
individualized determination. The OPP FQPA Safety Factor Committee (SFC) makes
specific case-by-case determinations as to the need and size of the additional
factor if reliable data permit. Determination of the magnitude of the overall
safety factor or margin of safety involves evaluating the completeness of the
toxicology and exposure databases and the potential for pre- or post-natal
toxicity. Individualized assessments may result in the use of additional factors
greater or less than, or equal to 10X, or no additional factor at all. (OPP
Guidance Document on Determination of the Appropriate FQPA Safety Factor(s) in
Tolerance Assessment, 2002)
The HIARC addressed the
potential enhanced sensitivity of infants and children from exposure to
glyphosate as required by the FQPA of 1996 at the March 26, 1998 meeting and
reaffirmed the decision at the November 20, 2001 meeting. The HIARC concluded
the following:
The FQPA SFC met on April
6, 1998 to evaluate the hazard and exposure data for glyphosate. The FQPA
SFC concluded that the safety factor of 10x be removed (reduced to 1x) since
there is no evidence of quantitative or qualitative increased susceptibility of
the young demonstrated in the prenatal developmental studies in rats and rabbits
and pre/post natal reproduction study in rats. In addition the toxicology data
base is complete, a developmental neurotoxicity study is not
required, and the dietary (food and drinking water) exposure assessments
will not underestimate the potential exposures for infants and children.
VII EXPOSURE ASSESSMENT
The exposure assessment is
the third step in the risk assessment process. The objective is to determine the
source, type, frequency, magnitude, and duration of actual or hypothetical
contact by humans with the agent of interest. To conduct this assessment EPA
relied upon the information provided by DoS from two sources: (1) Department of
State (DoS) Presentation, DoS Coca Eradication Program, 4/18/02, (2) DoS
document entitled Chemicals Used for the Aerial Eradication of Illicit Coca
in Colombia and Conditions of Application. These data were used in
accordance with standard policies and procedures used by the Agency in
conducting pesticide exposure assessments.
Dietary Food Exposure
Acute dietary exposure is
possible for persons consuming livestock or food crops which have been
inadvertently sprayed as a result of the aerial eradication program in Colombia.
However, since glyphosate is a contact herbicide that systemically kills plants
after absorption through leaves, dietary exposure due to consumption of treated
crops is expected to be limited. Since a coca field is sprayed no more than
twice to eradicate the crop, no chronic food exposure is expected. Based on an
evaluation of the hazard database, the Agency did not identify a toxic effect
attributed to a single oral dose. Therefore, an acute dietary risk assessment
was not performed (TXR No. 0050428, W. Dykstra, 22-JAN-2002). No significant
risk due to dietary exposure to glyphosate residues is expected.
Occupational Handler and
Post-application Exposure
Use Pattern Information
The tank mixture sprayed for
eradication of coca in Colombia contains 55% water, 44% of glyphosate herbicide
product, and 1% adjuvant (Cosmo-Flux 411F). No more than two applications of the
glyphosate tank mixture are sprayed over coca crops at a maximum of 1.25
gallons/Acre (equivalent to 1.1 gallons/Acre of glyphosate product, 0.03
gal/Acre of Cosmo-Flux 411F, and 0.12 gal/Acre of water). DoS also stated that
the average field size for coca in Colombia is 3-5 hectares (approximately 7-12
acres). The program for aerial eradication of coca treats a maximum of 1000
Acres/day, during 3-5 missions/day.
Handler Exposure
Exposure is expected for
workers mixing and loading the glyphosate formulated product and tank mix, and
applicators applying the pesticidal mixture via fixed-wing aircraft. Mixers,
loaders, and applicators (handlers) have the potential for dermal exposure to
the concentrate glyphosate formulated product or tank mix from droplets
contacting the skin. There is also the potential for inhalation exposure to the
concentrated glyphosate formulated product or mixed formulation from breathing
in aerosolized spray droplets.
According to the DoS, the
mixer/loaders are trained on the label requirements for handling the chemicals
in the spray mixture, first aid, and use of personal protective equipment (PPE).
The required PPE according to the label includes long-sleeved shirts and long
pants, waterproof gloves, shoes and socks, and protective eyewear. PPE is
expected to mitigate potential exposure to handlers. Exposure to handlers is
anticipated for short-term (1-30 days) durations. There also may be the
possibility for intermediate-term(1-6 months) handler exposure for individuals
mixing, loading, and applying the glyphosate mixture to multiple fields for more
than 30 days. However, the Agency does not have information pertaining to the
duration of coca spray programs or number of days spent mixing, loading, and
applying the glyphosate mixture.
An occupational handler
exposure and risk assessment is required for an active ingredient if: (1)
certain toxicological criteria are triggered and (2) there is potential exposure
to handlers (i.e., mixers, loaders, applicators, etc.) during use. Upon review
and analysis of the hazard database in total, the Agency’s HIARC did not
identify a hazard of concern for dermal or inhalation short- and
intermediate-term exposures. Therefore, quantitative estimates of risk for
short-term dermal and inhalation have not been conducted (TXR No. 0050428, W.
Dykstra, 22-JAN-2002). No significant handler risk is expected.
Post-application Exposure
According to the DoS,
Colombian coca plants (Erythroxylum species) are woody perennial shrubs native
to the Andean region. Coca plants have leaves with waxy cuticles which retard
herbicide uptake in the plant. The coca bushes grow to approximately chest level
and are harvested mainly by leaf pulling, 4 to 5 times per year. Coca plants
grow from seedlings to a harvestable plant in 12 to 18 months. Representatives
from DoS indicated that, growers will prune the coca plants, immediately after
spraying, in order to salvage the coca crop. Specifically, since glyphosate is a
contact herbicide that works systemically to kill the plant after absorption
through the leaves, workers may enter fields immediately after spraying in order
to prune or pull off the coca leaves in order to prevent the coca plant from
dying. In the US, most uses of glyphosate are applied to kill weeds - which are
the target. In general, glyphosate is not applied in the US to destroy or kill
the raw agricultural commodity. The intended US uses are for undesired
vegetation in and around crop fields, forests, industrial areas and residential
areas (for more detailed information, please refer to the June 28, 2002
memorandum entitled Description of Glyphosate Use in the U.S. for Comparison
to Use in Colombia for Coca Eradication from Virginia Werling and Timothy Kiely
to Jay Ellenberger).
DoS states that pilots are
instructed not to spray fields where people are present. Therefore, based on the
use pattern described by the DoS, potential short-term dermal exposures are
expected for persons pruning, or leaf pulling treated coca plants immediately
after spray events. These activities are expected to result in dermal exposure
from treated foliage contacting the skin. In cases such as glyphosate, where the
vapor pressure is negligible, HED experience with post-application data suggests
that inhalation exposure is minimal and therefore, HED does not quantitatively
assess post-application inhalation exposure. Intermediate- and long-term
post-application exposures are not expected due in part to the fact that a coca
field is sprayed no more than twice.
Additionally, glyphosate is
a translocated herbicide which is rainfast (unable to be rinsed off by water)
within 48 hours after spraying. Therefore, potential exposure to dislodgeable
residues of glyphosate after 48 hours is expected to be minimal. Glyphosate has
no residual soil activity. Results from the first 12 months of bareground field
dissipation trials from eight sites show that the median half-life (DT50) for
glyphosate (Roundup) applied at maximum annual use rates (7.95 lb a.i./acre,
10.7 lb a.i./acre) was 13.9 days with a range of 2.6 (Texas) to 140.6 (Iowa)
days. Acceptable aerobic soil, aerobic aquatic and anaerobic aquatic metabolism
studies demonstrate that under those conditions at 25oC in the
laboratory glyphosate degrades rapidly with half-lives of approximately 2, 7 and
8 days respectively. The reported half-lives (DT50) from the field studies
conducted in the coldest climates, i.e. Minnesota, New York. and Iowa, were the
longest at 28.7, 127.8, and 140.6 days respectively indicating that glyphosate
residues in the field are somewhat more persistent in cooler climates as opposed
to milder ones (Georgia, California, Arizona, Ohio, and Texas) (Memo,
J.Carleton, 10/26/98, D238931). The climate in Colombia would favor a shorter
half life than the colder regions of the US. Thereby, HED believes glyphosate
would not be persistent or be available for intermediate-term or long-term
post-application exposures in the Colombian climate.
A post-application exposure
and risk assessment is required for an active ingredient if: (1) certain
toxicological criteria are triggered and (2) there is potential exposure. Upon
review and analysis of the hazard database in total, the Agency’s HIARC did not
identify a hazard of concern for these durations or routes of exposure.
Therefore, quantitative estimates of risk for short-term dermal and inhalation
have not been conducted (TXR No. 0050428, W. Dykstra, 22-JAN-2002). No
significant post-application risk due to glyphosate exposure is expected as a
result of this use.
Incidental Oral Exposure
(Hand-to-Mouth)
Since DoS states that pilots
are instructed not to spray fields where people are present, incidental oral
exposure (hand-to-mouth) resulting from being directly sprayed by glyphosate was
not assessed. Non-dietary incidental oral exposure was not quantitatively
assessed for the use of glyphosate in Colombia.
As a point of comparison,
screening level risk estimates for toddler incidental oral exposures
(hand-to-mouth) to the U.S. for registered residential turf uses of glyphosate
have been calculated (D280831, Memo, W.Donovan, 20-FEB-2002). All resulting
risks for toddler incidental oral exposure do not exceed HED’s level of concern.
The assumptions for toddler incidental oral exposures, (based on the maximum
application rate of 1.62 lbs acid equivalent (ae)/Acre), are expected to be
conservative. For example, it is assumed that there is no dissipation of
transferable residues, so that toddlers are exposed to day of treatment
residues for each day of exposure. Even though the application rate for the coca
eradication program is higher (3.3 lbs ae/Acre), using the same standard
screening level assumptions as used in the residential assessment for the U.S.
registered turf use and taking the higher application rate into account, the
potential risk would not exceed HED’s level of concern.
As indicated in the turf
assessment, glyphosate was directly applied to residential lawns and did not
result in exposures of concern to HED. Although spray drift is always a
potential source of exposure to residents nearby aerial spraying operations,
AgDrift® (a spray drift model) consistently predicts drift from applications is
only a fraction of the applied rate (lb ai/acre). Based on this assessment, HED
believes that it is unlikely that there is a higher potential for risk of
exposure to spray drift from agricultural operations.
Eye Exposure
The greatest potential for
eye exposure is expected for workers mixing and loading the concentrated
glyphosate product. Potential exposure is expected through 2 main pathways: (1)
exposed hands transferring the glyphosate product to the eye(s), (2) splashing
of the liquid concentrated glyphosate product into the workers’eye(s). However,
the label requires mixer/loaders to wear protective eyewear and this level of
PPE is expected to mitigate the potential for eye exposure.
There is also the potential
for eye exposure as a result of entering treated fields immediately after
treatment to perform pruning or harvesting activities. Specifically, persons
dermally contacting treated foliage may transfer residues from the hand to the
eye. However, the Agency currently does not have a defined method or model to
assess quantitative eye exposures resulting from occupational or residential
exposures to pesticides. For products registered for use in the United States
which have high acute toxicity to the eye, mitigation of exposure to potential
eye effects for post-application workers is done by lengthening restricted entry
intervals (REI).
VIII SPRAY DRIFT
Due to spray drift, there is
potential exposure for persons in areas near those targeted for spraying.
Exposure through drift is not expected to exceed that which is identified in the
exposure characterization provided above. The coca eradication program described
by the Department of State has incorporated several features designed to
minimize the potential for off-target drift, provide quality assurance on a
mission-by-mission basis, and evaluate the performance of the program to the
extent possible given current conditions. Three types of aircraft are used in
the program including the Ayres Corporation T65 Thrush, modified OV10D Bronco
aircraft converted from military observation use to spray aircraft, and the Air
Tractor AT802. The T65 and AT802 are common to the agricultural sector in the
United States. The nozzles are Accu-Flow as described at the April 18, 2002
briefing to the Agency. The droplet spectra characteristics, under use
conditions for these nozzles, produce a very large droplet which has a volume
median diameter (VMD) between 300 and 1500 microns. Use of droplets this size is
consistent with minimizing spray drift in agriculture in the United States. A
surfactant (Cosmo-Flux 411F) is also used in the spray solution along with water
and the glyphosate formulated product. The use of spray adjuvants (in this case
Cosmo-Flux 411F) in pesticide product formulations and/or the spray solution is
also consistent with common agricultural practices in the United States.
The quality assurance
standard operating procedures identified as incorporated into the program are
also consistent with standard agricultural practices. These include
reconnaissance of the spray sites, use of global positioning satellite
technology (GPS), and criteria for aborting missions (e.g., based on
climatological conditions or presence of persons or livestock in the treatment
areas). Reconnaissance of spray sites is intended to define the treatment zones
through the use of sophisticated GPS mapping which is then overlaid with GPS
spray records from missions to evaluate performance. GPS technology is used for
planning, assessments of mission performance, and for archival purposes to
evaluate potential claims against the program.
Finally, to a limited extent
where feasible, DoS reports that on-site ground inspections for spray efficacy
and potential adverse effects are performed. Reports suggest approximately 90
percent efficacy in the spray swath and minimal collateral damage to surrounding
vegetation (e.g., aerial photos of treated areas) based on information supplied
by the DoS at the April 18, 2002 briefing.
The Agency did not complete
a quantitative risk analysis of the drift potential of glyphosate in the
water/surfactant solution used in this program. However, the technology and
other safeguards used in this program are consistent with common approaches in
the United States for reducing spray drift. Therefore, it is likely that drift
is minimized in this program if all procedures are adhered to and operational
equipment is in working order. At the April 2002 briefing, it was indicated to
the Agency that quantitative spray drift studies had been completed by the DoS
in conjunction with the University of Georgia. These were not supplied to the
Agency nor were they considered in this evaluation. Additionally, it should be
noted that the Agency did not review the primary source of information provided
(e.g., the method by which the VMD was determined was not described, written
application protocols describing target site conditions when applications would
be aborted were not provided, and methods for scoring or measuring off-target
damage were not provided).
IX INCIDENT DATA REVIEW: A STUDY OF
HEALTH COMPLAINTS RELATED TO AERIAL ERADICATION OF POPPY IN COLOMBIA
Dr. Jerry Blondell is a
health statistician and the point of contact for human incident data in the EPA
Pesticide Program. He has reviewed the poppy incident data from Colombia and
compared these data to the glyphosate incident data reported from California and
the Poison Control Center. The entire review can be found beginning on page 38
of this document.
The report, prepared by the
Department of Narino, Municipality of El Tablon De Gomez, makes a concerted
effort to identify any health problems that might be related to use of the
glyphosate tank mix in aerial eradication programs. The study was commissioned
by the U.S. Embassy in Bogota and conducted independently by Dr. Camilo Uribe,
Director of Clinica Uribe Cualla, the national poison control center. Sections
of this report are summarized below with the sections numbered in bold
corresponding to the original report.
An exact comparison of the
epidemiological data in Colombia (which is from aerial application to poppy)
relative to the conditions of use, presented at the April 18, 2002 briefing (for
aerial application to coca) by DoS to OPP risk assessors, would have limitations
and uncertainties. The briefing did not address the conditions of use for poppy.
DoS also did not provide human incident data for the coca eradication program.
Subsequent to the April 18 briefing HED received an e-mail communication from
OPP/ Field and External Affairs Division, stating that the application rate for
poppy was lower than that for coca. According to the DoS, the use pattern of the
glyphosate mixture on poppy also differs from the use on coca. Other details of
the differences between the two spray programs have not been supplied to the
Agency. Specifically, the Agency has no information as to the exact makeup of
the tank mixture sprayed on poppy, or whether the same glyphosate product and
adjuvants used in the coca eradication program were used in the poppy
eradication program. Therefore, generalized conclusions drawn from human
incident data as a result of application to opium poppy, in comparison to
conditions of use for the coca eradication program should be made with caution.
1.1 Description of
studied area
This report primarily
concerns the area around the municipality of El Tablon in southern Colombia. The
total population is given as 16,770, of which 89% is categorized as rural. The
main crops in this area include coffee, corn, wheat, oats, potatoes, and illicit
opium poppy. It is known that a variety of other pesticides, more toxic than
glyphosate, are used on these crops. The municipality has three health centers,
including Aponte, which is the focus of this report. The Aponte health center is
staffed by a medical doctor, a nurse, and a nurse’s aide. Aerial eradication of
the illicit opium poppy reportedly occurred in this region in June, July, and
November of 2000.
1.2 Morbidity and
mortality in the municipality of El Tablon
The Narino Departmental
Health Institute provided summary morbidity and mortality information for the El
Tablon De Gomez area and the Aponte settlement for the year 1999. Data for the
year 2000 had not yet been officially released, but estimates are provided.
These data are reported here to provide an approximate description of glyphosate
tank mix exposure upon use on coca fields in Colombia. However, no quantitative
conclusions can be drawn from these data. Six illnesses likely to be related to
pesticide exposure were identified and tabulated. They include, acute diarrhea,
acute respiratory infection, dermatitis, intoxication, conjunctivitis and
headache. The authors note that the first three illnesses listed (diarrhea,
respiratory infection, and dermatitis) are likely to be related to problems with
inadequate nutrition, housing, and lack of health services. The basis for this
listing of symptoms is not specified, but it does agree with the list of
symptoms likely to result from exposure to glyphosate products based on Poison
Control Center data, California surveillance reports, and the world literature.
Total morbidity for 1999 and estimated morbidity for 2000 are given in the Table
below for El Tablon De Gomez and the Aponte Settlement below. Note, however,
that the overwhelming majority of these illnesses did not occur at the time of
spraying and, therefore, could not be related to spray exposure.
Table 2. Morbidity
reported in the El Tablon De Gomez of Colombia in 1999 and estimated for 2000.
Pathology |
1999 |
2000 Estimated |
Acute diarrhea |
146 |
186 |
Acute respiratory infection |
568 |
506 |
Dermatitis |
209 |
265 |
Poisoning/Intoxication |
1 |
4 |
Conjunctivitis |
75 |
85 |
Headaches |
139 |
151 |
Total for 6 suspected illnesses |
1,138 |
1,197 |
Table 3. Morbidity
reported in the Aponte Settlement of Colombia in 1999 and estimated for 2000.
Pathology |
1999 |
2000 Estimated |
Acute diarrhea |
181 |
190 |
Acute respiratory infection |
199 |
222 |
Dermatitis |
210 |
180 |
Poisoning/Intoxication |
4 |
4 |
Conjunctivitis |
87 |
104 |
Headaches |
78 |
95 |
Total for 6 suspected illnesses |
759 |
795 |
The Aponte settlement is
contained within the El Tablon De Gomez area, where there has been a concern for
herbicide spraying-related health effects. Figures in the report are listed by
five separate age groups. This reveals that the majority of the cases of
diarrhea and respiratory infection occurred in children less than five years
old, as would be expected given known demographics of those health effects.
Nationwide data show that 53% of intoxications are suicides or suicide attempts,
but it is not clear how many of the four poisonings listed above might be
suicidal or, more importantly, are due to other products such as medications. In
both Tables 2 and 3 there is an increase of 5% from 1999 to the estimate for
2000 for the total of the six suspected illnesses. Given that spraying is
reported to have occurred in 2000 and not 1999, this suggests that the
overwhelming majority (95%) of illnesses reported would be background incidence
unrelated to the spraying of herbicide. The remaining 5% increase could be due
to a variety of causes and do not support a conclusion that the glyphosate tank
mixture was responsible for these complaints.
1.3 Epidemiological
monitoring system and mandatory notification
In addition to the summary
of general morbidity in the population, there is a mandatory health reporting
system in Colombia for 34 illnesses including pesticide poisonings. The review
of these records found no reports of pesticide poisoning for the municipality of
El Tablon in the year 2000 or the first 9 weeks of 2001. Weekly reports were
examined to determine how many pesticide poisonings were reported each month. It
did not appear that the times of spraying correlated with reports of pesticide
intoxication.
Table 4: Reports of
Pesticide Intoxication provided to the Narino Department of Health Institute,
Epidemiology Section January 12, 2000 through March 7, 2001.
Month/Year |
Number of Poisonings |
Month/Year |
Number of poisonings |
Poisonings occurring at time of spraying |
January 2000 |
0 |
July 2000 |
11 |
9 |
February 2000 |
0 |
August 2000 |
6 |
|
March 2000 |
8 |
September 2000 |
12 |
|
April 2000 |
13 |
October 2000 |
8 |
|
May 2000 |
7 |
November 2000 |
13 |
6 |
June 2000 |
15 |
December 2000 |
2 |
|
-- |
- |
Jan. 2001 |
7 |
|
-- |
- |
Feb. 2001 |
19 |
|
-- |
- |
Mar. 2001 |
0 |
|
Out of a total of 125
reported pesticide poisonings in 61 weeks, 15 occurred during 5 weeks when
spraying eradication occurred. Given the variation in the data, this could
easily be due to chance and be unrelated to exposure from the spraying of the
glyphosate tank mixture. More work is required to determine whether locations of
the 15 suspect poisoning matched the location and timing of spraying.
In 2000, the Narino
Department of Health requested all municipalities to report the human health
effects of pesticide spraying. Ten municipalities supplied the reports. They
are:
Three municipalities
including Tablon de Gomez, Barbacoas, and Magui reported no cases. However, the
reports were completed prior to the November spraying in Barbacoas and Magui and
prior to (or perhaps during) the July and before the November spraying in Tablon
de Gomez. Buesaco reported one patient with sore throat, numbness in limbs, and
conjunctivitis in June. In Tumaco, six case of patients with conjunctivitis and
dermatitis were reported as of October 6, 2000. In San Pablo, 50 cases of
dermatitis, conjunctivitis, respiratory conditions, and digestive problems were
reported after as of October 6, 2000.
In La Cruz, two cases of
allergic rhinitis, two cases of dermatitis, and five cases of conjunctivitis
were reported as of October 6, 2000. San Jose de Alban did not report any
specific cases, but the scientific coordinator and chief nurse noted an increase
in gastrointestinal, dermatological and respiratory conditions. The exact
quantity of these conditions in relation to spray times was not given. El
Rosario reported five cases of conjunctivitis and rhinitis that might have been
related to spraying carried out on July 31. San Pedro de Cartago reported an
increase in gastrointestinal symptoms but no quantitative relationship between
illnesses and spray times was provided.
The absence of any reports
of pesticide poisoning combined with the information from the ten municipalities
is difficult to interpret. The glyphosate formulated product is known to cause
irritation to the skin, eyes, mucous membranes which may account for some of the
reports of sore throat, conjunctivitis, dermatitis and other conditions
described above. However, it is not possible to evaluate these reports in any
detail due to the lack of any information on how many of these cases experienced
exposure immediately prior to their illness and lack of information on
investigation of potential alternative causes. This anecdotal information does
not provide any substantial evidence of health effects due to the spraying of
the glyphosate tank mixture in Colombia. Many of the reports are consistent with
exposure to glyphosate products by the dermal route, as reported in California
and the literature. So, it is possible that some cases could be related to the
aerial eradication program.
To provide context for
comparison, the California Pesticide Illness Surveillance Program (1982-2000)
data for glyphosate were reviewed for this risk assessment. Starting in 1992,
the glyphosate product was reformulated in the US to reduce the amount of
surfactant which posed a hazard to the eye. From 1982 through 1991, there were
221 illnesses involving the eye or 22.1 cases per year. From 1994 (allowing 2
years for the product to be introduced into trade and widespread use) through
2000, there were 65 illnesses involving the eye or 9.3 cases per year, a decline
of 58%. Therefore, these data support the finding that the reformulated
glyphosate product used since 1992, have resulted in a significant drop in
illnesses. Overall, the total illnesses due to glyphosate declined by 39% from
the 1982-1991 time period to the 1994-2000 time period, largely due to the
reduction in eye injuries.
2.2 Review of report of
January 22, 2001 visit to the municipality of El Tablon de Gomez.
A commission visited the
municipality of El Tablon on January 22, 2001 and spoke with Dr. Tordecilla and
reviewed health records of his patients. A number of records of skin conditions
were noted for the months of October, December 2000, and January 2001. The exact
number of cases, selection criteria, and method of analysis was not specified in
the summary report. Nevertheless, the commission concluded "that the information
available permitted the commission to consider only the possibility of an
association between exposure to pesticides and the effects". The commission
noted that it lacked the technical expertise, the data on dates and locations of
spraying, and therefore could not conclude whether the observed conditions were
related to pesticide exposure.
2.3 Interviews with
Narino department health officials regarding the spraying
Employees of the Narino
Department Health Institute were interviewed by Colombian authorities. A Fatima
Health Promoter thought children were most affected, suffering gastrointestinal
problems and eye irritation. One possible route of exposure was the village
water fountains which supply some of the drinking water. The most common
symptoms in children, according to the Health Promoter, were stomach aches and
vomiting, which were different from the most common symptoms of glyphosate
exposure reported by Lee et al. (2000), sore throat and nausea. This
inconsistency suggests that some cause other than glyphosate products was
responsible for the children’s complaints. The Health Promoter reported one case
of a boy with skin lesions like sores after the spraying. The Health Promoter
was particularly concerned that peasants receive more health care from the
government.
A nurse’s aide reported that
three or four patients with burning eyes, headache, and dizziness were seen at
her health center. One boy with a respiratory infection was sent to another
health center, later died. Medical records were sought to substantiate this
report but there was no clinical history, autopsy or other information to
support glyphosate spraying as a factor. She referred a patient with urinary
problems to the hospital. Subsequent review of the medical records of this case
did not find reference to glyphosate tank mix exposure and suggested an
infectious origin. There were also cases of dermatitis, headache, abdominal pain
and gastrointestinal symptoms, but she could not say whether the symptoms were
related to exposure to the spraying of glyphosate tank mixture.
Another nurse’s aide
reported by telephone that her impression was that the number of dermatological
consultations had increased. However, there was no clear association with
glyphosate tank mix exposure and many of the reasons for the consultations were
the same as in previous years when glyphosate was not used, so no clear
relationship between the spraying and these dermatological conditions was
identified.
Reports of anecdotal
evidence by nurse’s aides and the health promoter have not established a link
between the spraying of glyphosate tank mix and health effects. Follow-up to
determine the timing and evidence of exposure and examination of other potential
causes of these effects was not performed. These interviews do not add
significant evidence about the health risks from the use of glyphosate tank
mixture in Colombia.
2.5 Review of records of
patients treated at Aponte Health Center - Sept. 2000 to Jan. 2001
There were 29 cases reported
by Dr. Tordecelli and clinical records were obtained for 21 of them. Two other
reports of skin lesions were sought but could not be confirmed. After careful
review of the 21 records, it was determined that all but four cases were likely
due to other causes. Most had skin conditions known to be related to bacteria or
parasites, not chemical exposures and the onset of their symptoms did not
correspond with the times of spraying. There were seven patients whose symptoms
started after spraying and three of these were conditions known to be caused by
bacteria or parasites. For the remaining four cases possibly related to the
spraying of glyphosate tank mixture, one was an allergic reaction that had been
seen in this patient before when there was no spraying. A second and third case
were contact eczema that is endemic in this region and thought to be more likely
due to an infectious origin. One of these two cases did not initiate until 52
days after the last spraying. The fourth case was dermatitis on the thigh which
would typically be protected by clothing and thereby protected from aerial spray
applications. This reviewer agrees with the conclusion that "the twenty-one
clinical histories . . . reveals that any relationship between aerial
eradication with the herbicide glyphosate (tank mixture) and the skin conditions
treated in Aponte is unlikely".
In summary, the evidence
collected and presented in this report cannot confirm that the glyphosate tank
mixture used in Colombia as the likely cause of illness in the surrounding
community. There is suggestive evidence in the form of reported increases of
morbidity and reports from municipalities that some cases of relatively mild
complaints could have occurred in relation to the spraying eradication program.
Some of the reports appear to be similar to those reported in the literature and
by California. These cases report irritation to skin, eyes, and respiratory
passages and suggest that the Cosmo-Flux 411F added to the glyphosate product in
Colombia has little or no effect on the overall toxicity of the formulated
product.
Rather than review
incomplete medical records, it would be better to collect information
prospectively. For example, if pesticide poisoning is a mandatory reporting
condition, a form documenting the exposure, health effects and medical data on
each case could be designed and used to establish whether any particular
conditions might be related to spraying the glyphosate tank mixture. Without
prospective collection of data and follow up, it is difficult to evaluate
potential health effects of the glyphosate tank mixture sprayed in Colombia.
Better records of the time of exposure relative to the onset of symptoms would
also enhance interpretation of the incidence data.
X RISK CHARACTERIZATION
Risk characterization
combines the assessments of the first three steps to develop a qualitative or
quantitative estimate of the probability, that under the assumed conditions or
variables of the exposure scenario, that harm will result to an exposed
individual. Risk is equal to hazard multiplied by exposure. For the scenarios
that are relevant to the subject use, the Agency has not identified toxic
effects attributable to a single oral exposure, short- or intermediate-term
dermal, or short- or intermediate-term inhalation exposures (TXR No. 0050428, W.
Dykstra, 22-JAN-2002). Therefore, no quantification of exposure or risk was
performed. Nonetheless, it is appropriate to qualitatively characterize the
potential for risk concerns for this use.
From the review of
glyphosate product incident reports for the use on poppy, it should be
emphasized that the spraying reported to have occurred in 2000 and not in 1999
suggests, that the overwhelming majority (95%) of the illnesses reported would
be background incidents unrelated to the spraying of herbicide. The remaining 5%
increase could be due to a variety of causes and do not support a conclusion
that the spraying of the glyphosate tank mixture was responsible for these
complaints. Furthermore, the individual with the highest potential for exposure
would be the mixer loader. They are handling the concentrated glyphosate product
and the tank mix. The incident data that has been submitted to the Agency by
DoS, does not include any incident reports for those individuals. There is some
data to suggest that the poppy eradication program could have resulted in minor
skin, eye, or respiratory irritation, and perhaps headache or other minor
symptoms. However, the detailed information on the use, timing of application,
history of exposure, and medical documentation of symptoms related to exposure
to glyphosate tank mix were not available. The evidence collected and presented
in the epidemiology report cannot confirm that the glyphosate tank mixture used
in Colombia as the likely cause of a single illness. There is suggestive
evidence in the form of reported increases of morbidity and reports from
municipalities that some cases of relatively mild complaints could have occurred
in relation to the spraying eradication program. Some of the reports appear to
be similar to those reported in the literature and by California. These cases
report irritation to skin, eyes, and respiratory passages and suggest that the
Cosmo-Flux 411F added to the glyphosate product in Colombia has little or no
effect on the overall toxicity of the formulated product. The information so far
collected indicates that any increase in health problems is likely to be
relatively small at most and the severity of those symptoms is likely to be
minor to moderate at most. The Amazon Alliance and Earth Justice submission
provided little, if any, information on the number of persons affected, age and
sex, symptoms of illness, or diagnosis or treatment received. Without such
information EPA cannot even begin to characterize the extent and pattern of the
health effects claimed to result from glyphosate application. Given the limited
amount of documentation, none of the data in the report from Colombia provide a
compelling case that the spraying of the glyphosate mixture has been a
significant cause of illness in the region studied. Prospective tracking of
reports of health complaints, documenting times of exposure and onset of
symptoms, are recommended during future spray operations to evaluate any
potential health effects and ameliorate or prevent their occurrence.
The glyphosate formulated
product used in the coca eradication program in Colombia contains the active
ingredient glyphosate, a surfactant blend, and water. The acute toxicity test of
the glyphosate technical is classified as category III for primary eye
irritation and category IV for acute dermal and oral toxicity, and skin
irritation. It not a dermal sensitizer. However,
the surfactant used in the formulated product reportedly can cause severe
skin irritation and be corrosive to the eyes, as would be expected for many
surfactants. The label for the formulated product used in the coca
eradication program in Colombia includes the "Danger" signal word. The product
has been determined to be toxicity category I for eye irritation, causing
irreversible eye damage. Some of the findings reported in the incident data are
in alignment with that, reports of toxicity to the eye due to the surfactant,
not glyphosate per se. This is supported by data obtained from the
California Pesticide Illness Surveillance Program (1982-2000). As stated
previously, in 1992 the glyphosate product was reformulated in the US to reduce
the amount of surfactant which posed a hazard to the eye. From 1982 through
1991, there were 221 illnesses involving the eye or 22.1 cases per year. From
1994 (allowing 2 years for the product to be introduced into trade and
widespread use) through 2000, there were 65 illnesses involving the eye or 9.3
cases per year, a decline of 58%. Therefore, these data support the finding that
the use of the reformulated glyphosate product since 1992, has resulted in a
significant drop in illnesses. Overall, the total illnesses due to glyphosate
declined by 39% from the 1982-1991 time period to the 1994-2000 time period,
largely due to the reduction in eye injuries.
The acute toxicity of the
undiluted glyphosate product is most pertinent to mixers and loaders, who are
potentially exposed to that form of the glyphosate product. On April 18, 2002,
during a consultation with the DoS, in preparation for the current risk
assessment, the DoS agreed to supply the Agency with a full battery of the six
acute toxicity tests on the tank mix. To date, the Pesticide Program has not
received this data. Until such information is supplied to the Agency, EPA cannot
evaluate any potential acute toxicity effects resulting from direct contact with
the tank mixture. Therefore, due to the acute eye irritation caused by the
concentrated glyphosate formulated product and the lack of acute toxicity data
on the tank mixture, the Agency recommends that an alternative glyphosate
product (with lower potential for acute toxicity) be used in future coca and/or
poppy aerial eradication programs.
A direct comparison of the
epidemiological data in Colombia (which is from aerial application to poppy) to
the conditions of use, (as presented at the April 18, 2002 briefing for aerial
application to coca by DoS to OPP risk assessors), would be limited. The
briefing did not address the conditions of use for poppy. Subsequent to the
April 18 briefing HED received an e-mail communication from OPP/ Field and
External Affairs Division, stating that the application rate for poppy was lower
than that for coca. According to the DoS, the use pattern of the glyphosate
mixture on poppy differs from the use on coca. Other details of the differences
between the two spray programs have not been supplied to the Agency.
Specifically, the Agency has no information as to the exact makeup of the tank
mixture sprayed on poppy, or whether the same glyphosate product and adjuvants
used in the coca eradication program were used in the poppy eradication program.
The Agency also has questions as to the geographical area differences, the
frequency of repeated applications, and the size of the area treated on each
spray mission. Therefore, generalized conclusions drawn from human incident data
as a result of application to opium poppy, in comparison to conditions of use
for the coca eradication program should be made with caution.
In summary, HED concludes
that:
REFERENCES
HIARC Report for Glyphosate
(TXR No. 0050428, W. Dykstra, 22-JAN-2002)
Glyphosate in/on Pasture and
Rangeland Grasses, Roundup Ready® Wheat, and Nongrass Animal Feeds. (DP Barcode:
D280831, 20-FEB-2002)
Farmer, D.R., T.A. Kaempfe,
W.F. Heydens and W.R. Kelce. 2000. Developmental toxicity studies with
glyphosate and selected surfactants in rats. Teratology 61(6): 446.
US Environmental Protection
Agency, Office of Pesticide Programs May 9, 2002: Guidance Document on
Methodology for Determining the Data Needed and the Types of Assessments
Necessary to Make FFDCA Section 408 Safety Determinations for Lower Toxicity
Pesticide Chemicals.
Williams, G.M., R. Kroes and
I.C. Munro. 2000. Safety evaluation and risk assessment of the herbicide Roundup
and its active ingredient, glyphosate, for humans. Reg. Toxic. Pharm. 31:
117-165.
Certain references deleted
for protection of CBI.
SECTION 3. Review of Glyphosate Incident Reports with special reference
to aerial spraying in Colombia
BACKGROUND
On May 8, 2002 the U. S.
Department of State requested that the U.S. Environmental Protection Agency
provide consultation on the U.S.-supported aerial coca eradication program in
Colombia. Specifically, the Department of State requests advice on whether the
aerial application program may pose unreasonable risks or adverse effects to
humans or the environment. This review is part of a health risk assessment
performed by the Health Effects Division of the glyphosate product used in
Colombia. This review will focus on reports of human health effects reported
from the leading pesticide poisoning surveillance data sources in the United
States, which include Poison Control Centers and the California Pesticide
Illness Surveillance Program. The California data source is especially useful
for this review because of it’s high quality, documentation going back to 1982,
and because glyphosate is the second most widely used pesticide in California
affording ample opportunity for unintentional exposures. The world scientific
literature on glyphosate and a report from Colombia examining reports of the
adverse health effects are also reviewed.
The aerial spray mixture
used in Colombia consists of water, glyphosate formulation, and 1 percent
Cosmo-Flux 411F. According to documentation supplied by the Department of State,
this diluted mixture is applied to coca at the rate of 2.53 gallons per acre (U.
S. Department of State 2002). "The commercial glyphosate formulation used in the
spray mixture is registered with U. S. Environmental Protection Agency (EPA) for
sale in the United States for non-agricultural use and contains 41 percent
glyphosate salt and 59 percent inert ingredients. Approximately three fourths of
the inert ingredient content are water and the remainder is a surfactant blend.
A surfactant is essentially a soap that enhances the ability of the herbicide to
penetrate the waxy cuticle of the leaf surface."(U. S. Department of State
2002).
This review will not be able
to fully assess the formulation containing 1 percent Cosmo-Flux 411F because
that particular surfactant has not been used in the United States. Nevertheless,
it will consider the summary of the investigation in Colombia of the formulation
which does contain this additional surfactant. Though all aspects of glyphosate
human poisoning data will be considered, this review will focus on one
particular scenario, namely the effects of dermal and inhalation exposure from
spray drift or residues, that result from aerial application.
The following data bases
have been consulted for the poisoning incident data on the active ingredient
glyphosate (PC Code: 103601):
1) Poison Control Centers -
as the result of a data purchase by EPA, the Office of Pesticide Programs (OPP)
received Poison Control Center data covering the years 1993 through 1998 for all
pesticides. Most of the national Poison Control Centers (PCCs) participate in a
national data collection system, the Toxic Exposure Surveillance System which
obtains data from about 65-70 centers at hospitals and universities. PCCs
provide telephone consultation for individuals and health care providers on
suspected poisonings, involving drugs, household products, pesticides, etc. Note
that Poison Control Center data does not have information on the type of
application. So it is not possible to limit the review to the aerial application
scenario or to limit it to only those persons secondarily exposed to drift or
residue. However, it will be possible to exclude oral exposures which are
inconsistent with the focus of the present review.
2) California Department of
Pesticide Regulation - California has collected uniform data on suspected
pesticide poisonings since 1982. Physicians are required, by statute, to report
to their local health officer all occurrences of illness suspected of being
related to exposure to pesticides. The majority of the incidents involve
workers. Information on exposure (worker activity), type of illness (systemic,
eye, skin, eye/skin and respiratory), likelihood of a causal relationship, and
number of days off work and in the hospital are provided. The California data
permits assessing the risk of exposure both to handlers and to bystanders. The
exposure of bystanders and others to drift and residue will be a primary focus
of this review.
3) Scientific Literature - A
search was performed on Medline for scientific literature related to the human
health effects of glyphosate. All articles were retrieved and reviewed for
relevance. Articles involving dermal or ocular exposure are given priority
because this fits with the primary scenario of concern for this review.
4) A report from the
Department of Narino, Municipality of El Tablon De Gomez "A Study of Health
Complaints Related to Aerial Eradication in Colombia", Final Report dated
September 2001 is reviewed. This document addresses the specific exposure of
interest and therefore will be given special attention.
GLYPHOSATE REVIEW
I. Poison Control Center
Data - 1993 through 1998
Results for the years 1993
through 1998 are presented below for occupational cases, non-occupational
involving adults and older children, and for children under age six. Reports of
intentional exposures (e.g., suicide attempts) and exposures to multiple
products are excluded. Cases where the outcome was determined to be unrelated to
the exposure were also excluded. Tables 1-4 present the hazard information for
glyphosate compared with all other pesticides on six measures: percent with
symptoms, percent with moderate, major (includes life-threatening or residual
disability) outcome, percent with major outcome, percent of exposed cases seen
in a health care facility, and percent hospitalized and percent seen in a
critical care facility. There were no cases with a fatal outcome between 1993
and 1998. Table 1 reports the number of cases on which the data derived in
Tables 2-4 are based. Table 2 presents this information for occupational cases,
Table 3 for non-occupational cases involving adults and older children (six
years or older), and Table 4 for children under age six. Note that Table 2,
involving occupational exposure, is of less relevance to this review because it
is inconsistent with the exposure scenario of interest in Colombia.
Table 1. Number of
glyphosate exposures reported to the Toxic Exposure Surveillance System (AAPCC),
number with determined outcome, number seen in a health care facility for
occupational and non-occupational cases (adults and children six years and
older) and for children under six years of age only, 1993-1998 .
Subgroup |
Exposures |
Outcome determined |
Seen in Health Care Facility |
Occupational: adults and older children |
875 |
663 |
263 |
Non-occupational: adults and older children |
7491 |
5177 |
940 |
Children under age six |
4897 |
3589 |
207 |
Table 2. Comparison between
glyphosate and all pesticides for percent cases with symptomatic outcome (SYM),
moderate or more severe outcome (MOD), life-threatening or residual disability
(LIFE-TH), seen in a health care facility (HCF), hospitalized (HOSP), or seen in
an intensive care unit (ICU) reported to Poison Control Centers, 1993-1998 for
occupational cases only.
Pesticide |
SYM* |
MOD* |
LIFE-TH* |
HCF* |
HOSP* |
ICU* |
Glyphosate |
77.8% |
7.54% |
0.15% |
30.0% |
2.28% |
0.76% |
All Pesticides |
86.0% |
18.8% |
0.62% |
47.0% |
6.08% |
2.36% |
Ratio |
0.90 |
0.40 |
0.24 |
0.64 |
0.38 |
0.32 |
* Symptomatic cases based on
those cases with a minor, moderate, major, or fatal medical outcome. Denominator
for SYM, MOD, and LIFE-TH is the total cases where medical outcome was
determined. Denominator for HCF is all exposures. Denominator for HOSP and ICU
is all cases seen in a health care facility.
Table 3. Comparison between
glyphosate and all pesticides for percent cases with symptomatic outcome (SYM),
moderate or more severe outcome (MOD), life-threatening or residual disability
(LIFE-TH), seen in a health care facility (HCF), hospitalized (HOSP), or seen in
an intensive care unit (ICU) reported to Poison Control Centers, 1993-1998 for
non-occupational cases involving adults and older children.
Pesticide |
SYM* |
MOD* |
LIFE-TH* |
HCF* |
HOSP* |
ICU* |
Glyphosate |
61.9% |
4.27% |
0.15% |
12.5% |
2.87% |
0.85% |
All Pesticides |
68.5% |
10.5% |
0.36% |
16.4% |
6.24% |
2.67% |
Ratio |
0.90 |
0.41 |
0.43 |
0.76 |
0.46 |
0.32 |
* Symptomatic cases based on
those cases with a minor, moderate, major, or fatal medical outcome. Denominator
for SYM, MOD, and LIFE-TH is the total cases where medical outcome was
determined. Denominator for HCF is all exposures. Denominator for HOSP and ICU
is all cases seen in a health care facility.
Table 4. Comparison between
glyphosate and all pesticides for percent cases with symptomatic outcome (SYM),
moderate or more severe outcome (MOD), life-threatening or residual disability
(LIFE-TH), seen in a health care facility (HCF), hospitalized (HOSP), or seen in
an intensive care unit (ICU) for adults and children six years and older
reported to Poison Control Centers, 1993-1998 for children under six years
old.
Pesticide |
SYM* |
MOD* |
LIFE-TH* |
HCF* |
HOSP* |
ICU* |
Glyphosate |
23.5% |
0.45% |
0.056% |
4.23% |
3.38% |
0.48% |
All Pesticides |
21.8% |
1.40% |
0.12% |
16.4% |
4.78% |
1.36% |
Ratio |
1.08 |
0.32 |
0.47 |
0.26 |
0.71 |
0.35 |
* Symptomatic cases based on
those cases with a minor, moderate, major, or fatal medical outcome. Denominator
for SYM, MOD, and LIFE-TH is the total cases where medical outcome was
determined. Denominator for HCF is all exposures. Denominator for HOSP and ICU
is all cases seen in a health care facility.
Glyphosate clearly has a
pattern of much lower toxicity than other pesticides. When cases with symptoms,
moderate, and major medical outcome are evaluated, glyphosate not only has a
lower ratio than other pesticides, but the ratio tends to decrease markedly with
the more severe measure of outcome. Children under six years of age appear to
differ from this finding somewhat, but this appears to be due to relatively
small numbers. They had slightly more symptoms than children exposed to other
pesticides and the ratio for life-threatening or residual disability was
somewhat higher than the ratio for moderate outcome. This finding was based on
two cases. One of these case reported severe burns and the other experienced
multiple seizures which were considered to be unknown if related to the exposure
to glyphosate. If this latter case were not included, then the pattern of
decreasing ratio with more severe effect would be maintained. Overall,
glyphosate was less than half as likely to result in serious effects (moderate
or major outcome) as all pesticides combined based on over 9,000 exposures.
A similar pattern was seen
for cases receiving health care. For occupational cases (Table 2), the ratio of
cases receiving health care, hospitalization, and treatment in a critical care
unit were 0.66, 0.37, and 0.32 respectively, decreasing with increasing level of
medical care. A similar pattern was found for non-occupational adults and older
children whose respective ratios were 0.76 for health care, 0.46 for
hospitalization, and 0.32 for critical care. For children under six years of
age, there was one cases requiring critical care and only 7 cases hospitalized.
These relatively low numbers resulted in a ratio of 0.26 for health care, 0.71
for hospitalization, and 0.35 for critical care. When oral exposures, common
among children under age six, are excluded, there were only 2 cases hospitalized
and none required critical care treatment. Both of the children that were
hospitalized experienced seizures that were considered to be unknown if related
to their exposure to glyphosate. Thus, even in the most sensitive population,
young infants, there was no strong evidence of serious effects from glyphosate.
II. California Data -
1982 through 2000
Detailed descriptions of 911
cases involving glyphosate, submitted to the California Pesticide Illness
Surveillance Program (1982-2000), were reviewed. In 675 of these cases,
glyphosate was used alone or was judged to be responsible for the health
effects. These 675 cases include only those with a definite, probable or
possible relationship. Table 4 presents the types of illnesses reported by year.
Table 5 gives the total number of workers that took time off work as a result of
their illness and how many were hospitalized and for how long.
Table 4. Cases Due to
glyphosate in California Reported by Type of Illness and Year, 1982-2000.
Year |
Illness Type |
|||||
Systemica |
Eye |
Skin |
Respiratoryb |
Combinationc |
Total |
|
1982 |
7 |
27 |
12 |
- |
- |
46 |
1983 |
4 |
24 |
22 |
- |
2 |
52 |
1984 |
3 |
24 |
11 |
- |
- |
38 |
1985 |
7 |
23 |
11 |
- |
1 |
42 |
1986 |
6 |
20 |
6 |
- |
1 |
33 |
1987 |
5 |
18 |
8 |
- |
- |
31 |
1988 |
5 |
18 |
13 |
- |
1 |
37 |
1989 |
7 |
18 |
12 |
- |
- |
37 |
1990 |
6 |
21 |
18 |
1 |
3 |
49 |
1991 |
13 |
28 |
16 |
1 |
5 |
63 |
1992 |
11 |
18 |
12 |
- |
4 |
45 |
1993 |
6 |
12 |
11 |
- |
1 |
30 |
1994 |
5 |
12 |
6 |
- |
2 |
25 |
1995 |
4 |
17 |
14 |
- |
2 |
37 |
1996 |
6 |
8 |
7 |
- |
5 |
26 |
1997 |
3 |
7 |
10 |
- |
1 |
21 |
1998 |
4 |
8 |
6 |
2 |
3 |
23 |
1999 |
6 |
7 |
5 |
3 |
0 |
21 |
2000 |
4 |
6 |
6 |
1 |
2 |
29 |
Total |
112 |
316 |
206 |
8 |
33 |
675 |
a Category includes cases where skin,
eye, or respiratory effects were also reported.
b Category not used until 1990. Prior respiratory cases classified as
systemic.
c Category includes combined irritative effects to eye, skin, and
respiratory system.
Table 5. Number of Persons
Disabled (taking time off work) or Hospitalized for Indicated Number of Days
After Glyphosate Exposure in California, 1982-1999.
Time period |
Number of Persons Disabled |
Number of Persons Hospitalized |
One day |
47 |
- |
Two days |
28 |
1 |
3-5 days |
27 |
- |
6-10 days |
2 |
- |
more than 10 days |
19 |
- |
Unknown |
43 |
6 |
Starting in 1992, glyphosate
was reformulated to reduce the amount of surfactant which posed a hazard to the
eye. From 1982 through 1991, there were 221 illnesses involving the eye or 22.1
cases per year. From 1994 (allowing 2 years for the product to be introduced
into trade and widespread use) through 2000, there were 65 illnesses involving
the eye or 9.3 cases per year, a decline of 58%. Therefore, these data support
the finding that the reformulated glyphosate used since 1992, have resulted in a
significant drop in illnesses. Overall, the total illnesses due to glyphosate
declined by 39% from the 1982-1991 time period to the 1994-2000 time period,
largely due to the reduction in eye injuries. More important for the purpose of
this review are those illnesses involving bystanders or other workers exposed to
drift or residue, rather than handlers exposed directly to the product during
application, mixing/loading, maintenance, cleaning, repair, transport or
disposal. A variety of worker activities were associated with exposure to methyl
bromide as illustrated in Table 6 below.
Table 6. Illnesses by
Activity Categories for Glyphosate Exposure in California, 1982-1999
Activity Category |
Illness Category |
|||||
Systemica |
Eye |
Skin |
Respiratoryb |
Combinationc |
Total |
|
Applicator |
80 |
214 |
173 |
5 |
25 |
497 |
Mixer/Loader |
4 |
61 |
15 |
- |
1 |
81 |
Clean/Prepare/Repair |
3 |
16 |
9 |
- |
2 |
30 |
Transport/Disposal |
2 |
10 |
3 |
- |
- |
15 |
(Handler-subtotal) |
(89) |
(301) |
(200) |
(3) |
(28) |
(623) |
Direct Spray/Spill |
1 |
6 |
- |
1 |
- |
8 |
Drift |
12 |
4 |
2 |
2 |
3 |
23 |
Residue |
2 |
3 |
2 |
- |
2 |
9 |
Other and Unknown |
8 |
2 |
2 |
- |
- |
12 |
Total |
112 |
316 |
206 |
8 |
33 |
675 |
a Category includes cases where skin,
eye, or respiratory effects were also reported.
b Category not used until 1990. Prior respiratory cases classified as
systemic.
c Category includes combined irritative effects to eye, skin, and
respiratory system.
Table 6 shows that
activities that involve direct handling of glyphosate account for over 90% of
the illnesses. Only 43 illnesses, 6% of the total, could be ascribed to direct
spray/spill, drift, or residue, scenarios that could conceivably occur in
Colombia as a result of the spray eradication program. Note that the 43 cases
include 3 cases listed as unknown because the exposure could have been either
direct spray, drift, or residue which could not be determined. Among the 43
cases, 30 had a causal relationship classified as possible or 70% of the total.
Among all 675 cases, only 21% were classified as possible. Another 6 of the 43
cases were classified as having a probable relationship between exposure and
health effects and 7 had a definite relationship. Therefore, it should be noted
that the evidence for a causative relationship for the majority of cases
involving drift or residue is often lacking.
Of the 43 cases, 7 took one
day off of work as a result of their illness and 2 people took off two days, and
another 2 people took off three days. A possible case picking plums did not know
whether pesticides were applied prior to picking, took five days off work. A
possible case occurred in a teacher who reported headache, nausea, fatigue, and
vomiting after the glyphosate odor was sucked into her classroom by an
air-conditioning unit. The final case, a gardener, took 13 days off after
pulling weeds and possibly exposed to residue which got in his eyes, resulting
in pain, burning sensations, and impaired vision.
Most of the symptoms
reported in this group of 43 cases were relatively minor. Symptoms reported in
four or more individuals included eye irritation (includes itching, pain,
burning), conjunctivitis, rash, swelling, skin irritation (includes itching,
blisters, pain, or numbness), throat irritation or burning, nasal congestion,
headache, nausea, shortness of breath or breathing difficulty, and asthmatic
reactions. Note that these symptoms are consistent with those specified in the
fifth edition of Recognition and Management of Pesticide Poisonings
(Reigart and Roberts 1999) which states that glyphosate is "irritating to the
eyes, skin, and upper respiratory tract".
Many of the 43 cases
described in the California report involved heavier exposures than are likely to
occur as a result of aerial application. For example, most of the direct spray
cases resulted when a bystander was inadvertently sprayed by an applicator on
the ground and was often drenched. Illnesses due to residue were often the
result of extensive contact with soil or foliage recently treated with
glyphosate. Reports of illness from drift from an aerial application were
relatively rare, accounting for four of the 23 cases reported above.
Out of 1,384 incidents
related to drift reported to the California Pesticide Illness Surveillance
Program from 1982 through 1997, only 8 cases were related to glyphosate and
suffered mild to moderate effects such as headache, dizziness, coughing, sore
throat and chest pain. Two individuals reported an allergic reaction which
included hives and rash. Glyphosate is second most widely applied pesticide in
California (see Wilhoit et al. California EPA web site: http://www.cdpr.ca.gov/docs/pur/purmain.htm) and
unlike many other pesticides has never been responsible for a large number of
illnesses due to drift from a nearby application. California reported the number
of applications of glyphosate and all pesticides from 1991 through 1996 (see web
site for data). There were 5,576 systemic poisonings (possible, probable, and
definite) reported in this time period for all pesticides and 45 systemic
poisoning reported for glyphosate. The number of poisonings per 1,000
applications was 0.6204 for all pesticides and 0.0781, thus glyphosate had an
estimated rate of systemic poisoning that was only 12% that of all pesticides.
The review of California
illness reports suggest that even diluted glyphosate can be a cause of skin,
eye, or throat irritation. These effects are almost always self limiting and do
not require hospital admission for treatment. Only one of the 675 California
cases required hospitalization. This 1999 case occurred in an individual who had
severe respiratory problems after applying glyphosate on three successive days,
handled moldy grass clippings, and had pre-existing medical conditions,
including asthma.
Systemic illness (as opposed
to skin, eye, and respiratory illness), such as headache, nausea, and difficulty
breathing have been reported, in sensitive individuals, such as persons with
asthma. However, in most such cases, there was insufficient documentation to say
that these systemic effects were definitely due to their exposure to glyphosate.
There were only 3 systemic cases (primarily headache) due to spray drift that
were considered to have a definite or probable relationship between the exposure
and the illness.
III. Literature review
The literature review is
arranged according to principle route of exposure. Dermal and ocular routes are
of most interest because these are the routes of exposure that persons in
Colombia might experience as a result of aerial applications.
Dermal effects
Hindson and Diffey (1984a)
describe a case of a 64 year-old untanned Caucasian male who developed acute
dermatitis after spraying weeds with a glyphosate product. Patch testing with a
1% and 5% aqueous solution of the product were negative. However testing patches
followed by exposure to ultraviolet radiation did reveal a marked
papulovesicular reaction, indicating a phototoxic reaction. However, subsequent
questions were raised about the benzisothiazolone preservative used in this
weedkiller (Hindson and Diffey 1984b). Separate testing of the both the
glyphosate and the benzisothiazolone, revealed that the benzisothiazolone was
the phototoxic agent and not the glyphosate.
Maibach (1986) performed
extensive testing of 346 volunteers for evidence of dermal effects of glyphosate
including acute irritation, cumulative irritation, photoirritation, and allergic
and photoallergic contact potential. The test compound was 98.4% pure (made up
of 41% glyphosate) and contained isopropyamine salt of glyphosate, water and
surfactant. The test compound was used at full strength and diluted in distilled
water. All test subjects were adults and exposed by covering skin with non-woven
fiber patches. Baby shampoo, all purpose cleaner, and dishwashing liquid was
used for comparison. "Compared to the baby shampoo, the herbicide was
statistically indistinguishable in its irritant potential. The tests also show
that it did not induce sensitization, photoirritation or photosensitization."
The author noted, however, that he could not rule out the possibility that
product contaminants might cause sensitization in unusual circumstances. Mild
irritation was observed in a few individuals who had concentrated product
applied to the skin for 24 hours.
Wester et al. (1991)
examined the potential of glyphosate for skin binding, skin absorption and
residual tissue distribution. In vitro percutaneous absorption through
human skin into human plasma was reported to be no more than 2% over a
concentration range of 0.5-154 ug/cm2. Other testing in rhesus
monkeys will not be discussed here. The important finding from this study is
that relatively small amounts of glyphosate are absorbed across the skin and
therefore, absent moderate to high toxicity, dermal exposure is likely to result
in only dermal effects.
Talbot et al. (1991)
reviewed 93 cases of glyphosate exposure reported to the emergency room in
Taiwan from 1974 through September 30, 1989. Cases involving exposures to other
products were excluded. The majority of these cases were suicidal and involved
oral exposures. There were two dermal exposures reported both of which were
asymptomatic.
Temple and Smith (1992)
reviewed a series of cases reported to the New Zealand National Poisons
Information Centre. The majority of these cases were unintentional exposures,
mostly while spraying glyphosate containing herbicides. "In general, these cases
exhibited minor local irritant effects which were self limiting and responded
well to symptomatic and supportive care." The authors give three examples of
such cases. In the first case, the male adult accidently rubbed concentrate in
his eye and developed edema around the eye and the conjunctiva around the
cornea. These symptoms were associated with fast pulse, palpitations, elevated
blood pressure, headache, and slight nausea. His symptoms resolved with
treatment and he resumed work the next day. In the second example, a male adult
sprayed a double strength solution which contacted his hand due to a faulty hand
grip on the spray unit. He wiped his face which became swollen with
paraesthesia. These symptoms resolved over 48 hours and did not require specific
treatment. The third case was accidently drenched with diluted glyphosate. He
developed a vesicular skin eruption especially on his arms and hands associated
with burning and itching. This condition required treatment at two monthly
intervals.
In a review of skin
reactions to pesticides, O’Malley (1997) provided a brief review of glyphosate.
His summary is quoted below:
"While technical-grade glyphosate has been shown to be nonreactive in skin and
eye irritation studies on file with the California Department of Pesticide
Registration (CDPR), the 39% formulated product causes moderate levels of
irritation, a disparity probably due to irritant properties of surfactant(s) in
the latter. Virtually all of the cases of eye, skin, and respiratory irritation
reported in California have occurred in applicators of the formulated product,
and residue is not known to produce skin reaction. In the CDPR series, cases of
skin irritation associated with glyphosate were often associated with
contaminated work clothing occluding the material directly against the skin."
O’Malley’s finding is
supported by the California Pesticide Illness Surveillance Program, which is
regarded as the best, most comprehensive source of information on human
pesticide exposure in the United States (U.S. General Accounting Office 1993).
This information and the earlier review of data from California, strongly
support the conclusion that the dermal risk of glyphosate, as formulated in the
United States, is primarily to pesticide handlers with very little or minor risk
to others (e.g., bystanders) who may be exposed to glyphosate drift or residue.
There was one recent case
report in the literature of a 54 year-old man in Brazil who unintentionally
sprayed himself and developed skin lesions six hours later (Barbosa et al.
2001). He developed severe conjunctival hyperemia (excess blood flow) and a rash
which became blisters and persisted for 15 days. One month after the exposure he
developed symmetrical parkinsonian syndrome. The authors acknowledge that "it is
not possible to exclude the coincidence [idiopathic Parkinson’s disease] with
exposure to glyphosate" and add that no other report of parkinsonism induced by
glyphosate has been reported. The authors propose a possible mechanism for
excitatory mechanisms but characterize their finding as a hypothesis. Other more
detailed studies are underway to determine whether pesticides might be related
to Parkinson’s disease and any conclusions about the potential involvement of
glyphosate will have to await the results of those studies.
Williams et al. (2000)
prepared an extensive risk assessment and safety evaluation of glyphosate,
partly supported by scientists with the manufacturer. They cite a study by
Jauhiainen et al. (1991) which evaluated short-term effects among five forest
applicators. and compared results with pre-exposure baseline as well as to data
from a group of five controls. "There were no effects on hematology, clinical
chemistry, ECG, pulmonary function, blood pressure, or heart rate 1 week after
application." They also cited California data as reviewed by Pease et al. (1993)
and noted that irritation of skin and eye effects were common, but not
exceptional taking into account the widespread product use. Reviewing the Temple
and Smith (1992) report (reviewed above), Williams et al. suggest that the
systemic symptoms reported (e.g., headache, fast pulse, slight nausea) "probably
represent a nonspecific response related to pain associated with eye and/or skin
irritation." Other studies cited by Williams related to dermal effects have
already been reviewed above.
Ocular effects
Acquavella et al. (1999) reviewed ocular effects reported to the American
Association of Poison Control Centers in the United States from 1993 through
1997. They identified 1513 records involving ocular or dermal/ocular exposure.
Information from patient notes kept by at least one Poison Center were also
reviewed. More than 80% of the exposures were residential and about 15% were
occupational. Only 5% of the calls involved concentrated product. "Approximately
70% of callers had minor effects, primarily transient irritations, attributed to
exposure. Ninety-nine percent of those with minor effects complained of eye
pain, 3% complained of lacrimation (watery eyes), and 3% complained of blurred
vision." Those exposed to more concentrated formulations (>2% glyphosate,
>1%Polyethoxylated tallow amine) were more likely to report lacrimation but not
blurred vision, however, there was little evidence of a trend between
concentration categories and lacrimation. A total of 30 callers (2%) were
classified as having a moderate medical outcome, such as persistent irritations,
low grade corneal burns or abrasions. There was one caller (0.1%) with a major
effect - scarring of the upper palpebral conjunctiva. This patient was wearing
extended wear contact lenses that were rinsed and replaced right after the
exposure. Over the next 17 days the patient had a corneal abrasion and
conjunctivitis which resolved as the vision returned to its pre-exposure state.
The additional information on this case suggests the case should be reclassified
as moderate because the scarring of the tear duct system, which was thought to
be permanent, did heal. There were 95 calls lost to follow-up where medical
outcome remained undetermined. In summary, there was some temporary injury in
about 2% of the reported cases, but no case of permanent damage.
Inhalation exposure
Jamison et al. (1986)
conducted a study of pulmonary function in workers handling flax which had
previously had the fibers softened and separated and either wetted or treated
with glyphosate 6 weeks prior to harvest. The authors concluded that workers had
a significant decrease in pulmonary function which was likely due to exposure to
the dust. Though there was very little residue of glyphosate at the end of the
six weeks, the authors stated that glyphosate could not "be excluded as a cause
of the increase pulmonary function impairment observed." However, Williams et
al. (2000) took issue with this view, noting that the levels of glyphosate would
be very low, "if present at all, and could not be responsible for the altered
pulmonary function observed." They felt the production of dust particles and/or
different microorganisms during the process were a more likely explanation.
Pushnoy et al. (1998)
reported on a 42 year-old mechanic who cleaned and repaired a spray rig in a
confined space. He reported to the emergency department complaining of shortness
of breath, irritative cough, dizziness, discomfort in the throat, and coughing
up blood. He was admitted to the hospital and diagnosed with acute chemical
pneumonitis. The authors suggested that the polyoxyethylene amine surfactant was
largely responsible for irritant effects on the mucosal lining and lung tissue,
and therefore, the likely cause of the pneumonitis. Goldstein et al. (1999, 5
authors with industry and one with Yale University) took issue with the findings
of Pushnoy et al. They argued that neither glyphosate nor any compound in the
finished product could vaporize sufficiently even in a poorly ventilated space
to cause such an exposure. They added that occupational pneumonitis had never
been reported in connection with glyphosate products. The original authors
replied that a longer presentation of the circumstances surrounding this case
would have permitted Goldstein et al. to reject the alternative exposures (e.g.,
chlorinated solvent, diesel fuel, welding) they suggested. They further state
that even though the vapor pressure of glyphosate was low "we have concluded
that the patient’s clinical symptomatology resulted from exposure and inhalation
of a mixture of vapor and air-borne droplets containing glyphosate . . . that
part of the parenchymal reaction was due to the effect of a surfactant (such as
polyoxyethylene amine) on the alveolar lining". However, the authors acknowledge
that the effect of the surfactant, though it seems plausible, is "based just on
clinical evidence".
Oral exposure
Inadvertent oral exposure to
glyphosate sprayed on coca plants in Colombia is extremely unlikely. Therefore,
the review of the scientific literature on oral exposure will be cursory. In a
letter to Lancet Sawada et al. (1988) reported on 56 ingestions of glyphosate
product. They found that the average dose among fatal cases was 104 ml and 206
ml among fatal cases. They describe the clinical picture as one of hypovolaemic
shock likely due to the 15% polyoxyethylene amine surfactant. Of the 56 cases
reviewed, 48 cases were attempted suicides, 3 unintentional (all infants), and 5
with unknown intent. Jackson (1988 with Monsanto) responded to the Sawada et al.
report and stated that there were no reports of deaths following accidental
ingestion.
Kageura et al. (1988)
reported on the death of a 26 year old woman who ingested glyphosate in a
suicide. They attributed the death to inhalation of vomitus into the lungs
causing asphyxiation. Talbot et al. (1991) reviewed 93 cases of glyphosate
exposure reported to the emergency room in Taiwan from 1974 through September
30, 1989. Cases involving exposures to other products were excluded. The
majority of these cases were suicidal and involved oral exposures. Those cases
where the amount ingested was not recorded were also excluded. They noted that
some cases had only moderate effects even after ingestion of up to 500 ml and
death had resulted from ingestion of concentrate in amounts above 85 ml. Oral
ingestions by mistake in seven cases was usually of a small amount and "resulted
in only minor mouth discomfort". The authors concluded that "the data suggest
that those over 40 years of age, who ingest more than 100 ml, are at the highest
risk of a fatal outcome."
Tominack et al. (1991)
reported on 97 telephone consultations with the Taiwan National Poison Center
involving ingestion of glyphosate-surfactant herbicide concentrate from January
1986 through September 1988. Eighty-eight cases were suicidal, five
unintentional, and four with uncertain intention. Non-fatal cases ingested an
average of 120 ml (range 5-500 ml) and fatal cases averaged 263 ml (range
150-500 ml). Of these 97, 12 were asymptomatic, 28 had mild, 33 had moderate,
and 16 had severe symptoms. Increasing dose and increasing age were significant
predictors of fatality. It should be noted that 10 of the 97 cases ingested
another substance in addition to glyphosate. They found that ingestion of a
mouthful of concentrate or more was capable of producing symptoms including
gastrointestinal mucosal injury, pulmonary edema, decreased or absent urine
output, metabolic acidosis, leukocytosis, fever, and hypotension that possibly
could develop into shock. Similar to the paper cited above, a dose of 150 ml or
more and age of 40 years or more were found to be at highest risk of fatal
outcome.
Menkes et al. (1991)
reported on four cases of suicidal ingestion of glyphosate, one of them fatal.
Two of the cases experienced massive fluid and electrolyte loss, probably due to
tubular necrosis. After considering all of the evidence concerning the
glyphosate and the surfactant the authors stated "it seems unlikely that
toxicity can be ascribed solely to the surfactant."
Temple and Smith (1992)
reviewed a series of cases reported to the New Zealand National Poisons
Information Centre. The majority of these cases were unintentional. Three
ingestions are described, two of them fatal. The authors concluded "Small
ingestions (less than 5 ml of the concentrate in adults) pose little problem and
simple dilution to minimize gastrointestinal irritation should suffice."
Hung et al. (1997) reviewed
53 cases reported between 1992 and 1996 in Taiwan to assess laryngeal injury. Of
these, 36 reported significant laryngeal injury was strongly correlated with
aspiration pneumonitis (reported in 8 cases). The average amount ingested in
such cases was 300 ml.
Lin et al. (1999) reported
on a suicide case who drank 150 ml of concentrate (41% isopropylamine salt of
glyphosate, 15% polyoxyethylene amine). This 26 year-old man experienced
cardiogenic shock which may have been due to transient suppression of the
cardiac conduction system and contractility, rather than intravascular
hypovolemia.
Chang et al. (1999) reported
on 50 patients with suicidal glyphosate-surfactant ingestions and evaluated
their upper gastrointestinal tract injuries. Esophageal injury was seen in 68%
of patients, gastric injury in 72%, and duodenal injury in 16%. The authors
considered these injuries "minor in comparison with those by other strong
acids."
Lee et al. (2000) reviewed
131 cases of glyphosate ingestion seen in their emergency department in Taiwan
over a seven year period. There were 11 fatalities (mortality rate 8.4%). The
most common presentations included sore throat (80%), nausea (74%), vomiting,
and fever (41%). The most common laboratory abnormalities were leukocytosis
(68%), low bicarbonate (48%), acidosis (36%), elevated AST, hypoxemia (28%), and
elevated BUN. Of the 81 cases receiving an electrocardiogram, 15 were abnormal,
mainly sinus tachycardia and nonspecific ST-T changes. Twenty-two of 105
patients who had chest x-rays had abnormal infiltrates or patches. Three
patients with renal failure all died. Poor outcome was predicted by respiratory
distress, renal dysfunction, abnormal CXR, shock, and ingestion of 200 ml or
more, altered consciousness, hyperkalemia, and pulmonary edema. The 11 cases
that died ingested an average of 330 ml which was higher than the previous
reports by Sawada et al. (1988) and Tominack et al. (1991). The authors propose
that direct damage to the airway passage is an important factor in severe
poisoning.
Reproductive effects
There were two studies
located that evaluated reproductive outcome in farmers handling pesticides that
specifically analyzed for the effects of glyphosate. However, these studies are
both retrospective, subject to numerous biases and confounders, and only suggest
associations rather than causative relationships. Thus any of these finding
would require replication and further evaluation before they could become
established. These studies are summarized below.
Savitz et al. (1997)
examined male pesticide exposure three months before conception and through
conception in relation to pregnancy outcome in an Ontario farm population. The
risk for miscarriage was not statistically significant, though somewhat elevated
for glyphosate users. This finding was true for both use of glyphosate on crops
(17 cases) and in yards (13 cases). A similar result was found for preterm
delivery based on 5 cases involving crop use of glyphosate. On the other hand,
there was no statistical significance or elevation of risk for small for
gestational age infants. The authors acknowledge that the lengthy recall
interval may have reduced the quality of information collected on exposure and
health outcome. They advise "Replication of these findings in other geographic
settings in a study of similar quality would be of value; however, to improve on
our strategy, the availability of unusually detailed source of historical
exposure data would be necessary."
Arbuckle and Mery (2001)
evaluated the risk of spontaneous abortion in the same Ontario farm population
examined by Savitz et al. (1997). In this refined analysis they found that late
abortions were statistically associated with preconception exposure to
glyphosate (odds ratio = 1.7, 95% confidence interval 1.0-2.9). This finding is
only just marginally significant. The authors state their findings have "several
limitations . . . Because dose information was not available, misclassification
of exposure is likely." Finally they state their "analyses were designed to
generate, not to test, hypotheses". Due to the fact that multiple comparisons
were conducted some findings may be due to chance.
IV. A Study of Health
Complaints Related to Aerial Eradication in Colombia
This report, prepared by the
Department of Narino, Municipality of El Tablon De Gomez, makes a concerted
effort to identify any health problems that might be related to use of
glyphosate in aerial eradication programs. The study was commissioned by the
U.S. Embassy in Bogota and conducted independently by Dr. Camillo Uribe,
Director of Clinica Uribe Cualla, the national poison control center. Sections
of this report are summarized below with the sections numbed in bold as
in the original report.
1.1 Description of
studied area
This report primarily
concerns the area around the municipality of El Tablon in southern Colombia. The
total population is given as 16,770, of which 89% is categorized as rural. The
main crops in this area include coffee, corn, wheat, oats, potatoes, and illicit
opium poppy. It is known that a variety of other more toxic pesticides are used
on these crops. The municipality has three health centers, including Aponte,
which is the focus of this report. The Aponte health center is staffed by a
medical doctor, a nurse, and a nurse’s aide. From July 2000 to February 2001,
the primary time period of this report, Dr. Tordecilla was the medical doctor.
Aerial eradication of the illicit opium poppy reportedly occurred in this region
in June, July, and November of 2000.
1.2 Morbidity and
mortality in the municipality of El Tablon
The Narino Departmental
Health Institute provided summary morbidity and mortality information for the El
Tablon De Gomez area and the Aponte settlement for the year 1999. Data for the
year 2000 had not yet been officially released, but estimates are provided by a
method not specified. Six illnesses likely to be related to pesticide exposure
were identified and tabulated, including acute diarrhea, acute respiratory
infection, dermatitis, intoxication, conjunctivitis and headache. The author
notes that the first three illnesses listed (diarrhea, respiratory infection,
and dermatitis) are likely to be related to problems with inadequate nutrition,
housing, and lack of health services, rather than due to pesticide exposure. The
basis for this listing of symptoms is not specified, but does agree fairly well
with the list of symptoms likely to result from glyphosate exposure based on
Poison Control Center data, California surveillance reports, and the world
literature. Total morbidity for 1999 and estimated morbidity for 2000 are given
in the Table below for El Tablon De Gomez and the Aponte Settlement below:
Table 7. Morbidity reported
in the El Tablon De Gomez of Colombia in 1999 and estimated for 2000.
Pathology |
1999 |
2000 Estimated |
Acute diarrhea |
146 |
186 |
Acute respiratory infection |
568 |
506 |
Dermatitis |
209 |
265 |
Poisoning/Intoxication |
1 |
4 |
Conjunctivitis |
75 |
85 |
Headaches |
139 |
151 |
Total for 6 suspected illnesses |
1,138 |
1,197 |
Table 8. Morbidity reported
in the Aponte Settlement of Colombia in 1999 and estimated for 2000.
Pathology |
1999 |
2000 Estimated |
Acute diarrhea |
181 |
190 |
Acute respiratory infection |
199 |
222 |
Dermatitis |
210 |
180 |
Poisoning/Intoxication |
4 |
4 |
Conjunctivitis |
87 |
104 |
Headaches |
78 |
95 |
Total for 6 suspected illnesses |
759 |
795 |
It appears the Aponte
settlement is contained within the El Tablon De Gomez area, though this is not
entirely clear. The figures in the report are listed by five separate age
groups. This reveals, that the majority of the cases of diarrhea and respiratory
infection occurred in children less than five years old, as would be expected
given the known demographics of those diseases. Nationwide data show that 53% of
intoxications are suicides or suicide attempts, but it is not clear how many of
the 13 poisonings listed above might be suicidal or, more importantly, are due
to other products such as medications. In both Tables 7 and 8 there is an
increase of 5% from 1999 to the estimate for 2000. Given that spraying is
reported to have occurred in 2000 and not in 1999, this suggests that the
overwhelming majority (95%) of illnesses reported would be background incidence
unrelated to the spraying of herbicide. The remaining 5% increase could be due
to a variety of causes and do not support a conclusion that glyphosate was
responsible for these complaints.
1.3 Epidemiological
monitoring system and mandatory notification
In addition to the summary
of morbidity, there is a mandatory health reporting system in Colombia for 34
illnesses including pesticide poisonings. The review of these records found no
reports of pesticide poisoning for the municipality of El Tablon in the year
2000 or the first 9 weeks of 2001. Weekly reports from Attachment 5 were
examined to determine how many pesticide poisonings were reported each month. It
was not clear whether the dates on each report represented the starting date or
ending date for a reporting period. Regardless of which is correct, it did not
appear that the times of spraying correlated with reports of pesticide
intoxication.
Table 9. Reports of
Pesticide Intoxication provided to the Narino Department of Health Institute,
Epidemiology Section January 12, 2000 through March 7, 2001.
Month in 2000 |
Number of Poisonings |
Month in 2000 or 2002 |
Number of poisonings |
Poisonings occurring at time of spraying |
January |
0 |
July |
11 |
9 |
February |
0 |
August |
6 |
|
March |
8 |
September |
12 |
|
April |
13 |
October |
8 |
|
May |
7 |
November |
13* |
6* |
June |
15 |
December |
2 |
|
-- |
- |
Jan. 2001 |
7 |
|
-- |
- |
Feb. 2001 |
19 |
|
-- |
- |
Mar. 2001 |
0 |
|
* Reports for weeks number 43 and 44 in
the first half of November were missing.
Out of a total of 121
reported pesticide poisonings in 61 weeks, only 15 occurred during 5 weeks when
spraying eradication occurred. This given the variation in the data, this could
easily be due to chance and be unrelated to glyphosate exposure. More work would
be required to determine whether locations of the 15 suspect poisoning matched
the location and timing of spraying.
In 2000, the Narino
Department of Health requested all municipalities to report on the effects of
spraying on human health. Ten municipalities supplied the following reports:
Three municipalities
including Tablon de Gomez, Barbacoas, and Magui reported no cases. However, the
reports were completed prior to the November spraying in Barbacoas and Magui and
prior to (or perhaps during) the July and before the November spraying in Tablon
de Gomez.
Buesaco reported one patient
with sore throat, numbness in limbs, and conjunctivitis in June.
In Tumaco, six case of
patients with conjunctivitis and dermatitis were reported.
In San Pablo, 50 cases of
dermatitis, conjunctivitis, respiratory conditions, and digestive problems were
reported after spraying.
In La Cruz, two cases of
allergic rhinitis, two cases of dermatitis, and five cases of conjunctivitis
were reported.
San Jose de Alban did not
report any specific cases, but the scientific coordinator and chief nurse noted
increase in gastrointestinal, dermatological and respiratory conditions. The
exact quantity of these conditions in relation to spray times was not given.
El Rosario reported five
cases of conjunctivitis and rhinitis that might have been related to spraying
carried out on July 31.
San Pedro de Cartago
reported an increase in gastrointestinal symptoms but no quantitative
relationship between illnesses and spray times was provided.
The absence of any reports
of pesticide poisoning combined with the information from the ten municipalities
is difficult to interpret. Glyphosate is known to cause irritation to the skin,
eyes, mucous membranes which may account for some of the reports of sore throat,
conjunctivitis, dermatitis and other conditions described above. However, it is
not possible to evaluate these reports in any detail due to the lack of any
information on how many of these cases experienced exposure immediately prior to
their illness and lack of information on investigation of potential alternative
causes. This anecdotal information does not provide any substantial evidence of
health effects due to glyphosate spraying in Colombia. Many of the reports are
consistent with exposure to glyphosate by the dermal route, as reported in
California and the literature. So, some number of cases (impossible to estimate)
could be related to the aerial eradication program.
2.2 Review of report of
January 22, 2001 visit to the municipality of El Tablon de Gomez.
A commission visited the
municipality of El Tablon on January 22, 2001 and spoke with Dr. Tordecilla and
reviewed health records of his patients. A number of records of skin conditions
were noted for the months of October, December 2000, and January 2001. The exact
number of cases, selection criteria, and method of analysis was not specified in
the summary report. Nevertheless, the commission concluded "that the information
available permitted the commission to consider only the possibility of an
association between exposure to pesticides and the effects". The commission
noted that it lacked the technical expertise, the data on dates and locations of
spraying, and therefore could not conclude whether the observed conditions were
related to pesticide exposure.
2.3 Interviews with
Narino department health officials regarding the spraying
Employees of the Narino
Department Health Institute were interviewed. According to a Fatima Health
Promoter, he/she thought the children were most affected, suffering
gastrointestinal problems and eye irritation. One possible route of exposure was
the village water fountains that were reportedly sprayed and that water could
reach the water that supplies the settlement. The most common symptoms in
children, according to the Health Promoter, were stomach aches and vomiting,
which were different from the most common symptoms reported by Lee et al. (2000)
which were sore throat and nausea. This suggests that some cause other than
glyphosate was responsible for the children’s complaints. He/she reported one
case of a boy with skin lesions like sores after the spraying. He/she was
particularly concerned that peasants receive more health care from the
government. He/she also noted that he lost a considerable sum of money when most
of his peas were affected by the spraying in June. He/she claimed to have a tape
made during the spraying by pilots where they were heard to say they would dump
the remainder of their herbicide in a field because they had too much quantity.
A nurse’s aide reported that
three or four patients with burning eyes, headache, and dizziness were seen at
her health center. One boy with a respiratory infection was sent to another
health center where he arrived dead. Medical records were sought to substantiate
this report but there was no clinical history, autopsy or other information to
support it. She referred a patient with urinary problems to the hospital.
Subsequent review of the medical records of this case did not find reference to
glyphosate exposure and suggested an infectious origin. She said there had been
cases of dermatitis, headache, abdominal pain and gastrointestinal symptoms, but
could not say whether the symptoms were related to glyphosate exposure. She also
was concerned that the government supply aid to this needy population,
especially better health services.
Another nurse’s aide
reported by telephone that her impression was that the number of dermatological
consultations had increased. She admitted her impression was subjective and that
the reasons for the consultations were the same as in previous years, so she
would not commit to there being a relationship between the spraying and these
dermatological conditions.
Reports of anecdotal
evidence by nurse’s aides and the health promoter have little value for
establishing any link between the spraying of glyphosate and health effects.
Only with follow-up to substantiate the suspicions could a more substantial case
be made. These interviews do no add significant evidence about the health risks
of glyphosate used in Colombia.
2.4 Video
Some videos made by
reporters were reported at the Aponte Health Center. One of these videos was
located and reviewed. It purported to show spraying on November 3, 2000 which
caused unspecified "calamities". However, specific evidence of health complaints
in humans was, apparently, not provided.
This video does provides
opinion but does not add substantive information about the potential health
effects of glyphosate used in Colombia.
2.5 Review of records of
patients treated at Aponte Health Center - Sept. 2000 to Jan. 2001
There were 29 cases reported
by Dr. Tordecelli and clinical records were obtained for 21 of them. Two other
reports of skin lesions were sought but could not be confirmed. After careful
review of the 21 records, it was determined that all but four cases were likely
due to other causes. Most had skin conditions known to be related to bacteria or
parasites, not chemical exposures and the onset of their symptoms did not
correspond with the times of spraying. There were seven patients whose symptoms
started after spraying and three of these were conditions known to be caused by
bacteria or parasites. For the remaining four cases possibly related to
glyphosate spraying, one was an allergic reaction that had been seen in this
patient before when there was no spraying. A second and third case were contact
eczema that is endemic in this region and thought to be more likely due to an
infectious origin. One of these two cases did not initiate until 52 days after
the last spraying. The fourth case was dermatitis on the thigh which would
typically be protected by clothing and thereby protected from aerial spray
applications. This reviewer agrees with the conclusion that "the twenty-one
clinical histories . . . reveals that any relationship between aerial
eradication with the herbicide glyphosate and the skin conditions treated in
Aponte is unlikely".
In summary, the evidence
collected and presented in this report cannot confirm the glyphosate used in
Colombia as the likely cause of a single illness. There is suggestive evidence
in the form of reported increases of morbidity and reports from municipalities
that some cases of relatively mild complaints could have occurred in relation to
the spraying eradication program. Some of the reports appear to be similar to
those reported in the literature and by California. These cases report
irritation to skin, eyes, a respiratory passages and suggesting that the
Cosmo-Flux 411F added to the glyphosate in Colombia has little or no effect on
the overall toxicity of the formulated product. If true, this would mean that
the evaluation of glyphosate, as used in the United States and elsewhere, would
be expected to have the same toxicologic properties and effects as glyphosate
formulated in Colombia.
Rather than review
incomplete medical records, it would be better to collect information
prospectively. For example, if pesticide poisoning is a mandatory reporting
condition, a form documenting the exposure, health effects and medical data on
each case could be designed and used to establish whether any particular
conditions might be related to spraying glyphosate. Without prospective
collection of data and follow up it is difficult to evaluate potential health
effects of glyphosate.
V. Conclusions
There is some data to
suggest that the spray eradication program could have resulted in minor skin,
eye, or respiratory irritation, and perhaps headache or other minor symptoms.
However, the detailed information on timing of application, history of exposure,
and medical documentation of symptoms related to glyphosate exposure were not
available. Thus, not a single case of the reported symptoms can be confirmed as
caused by the spray applications. The information so far collected gives the
impression that any increase in health problems is likely to be relatively small
at most and the severity of those symptoms is likely to be minor to moderate at
most. Given the limited amount of documentation, none of the data in the report
from Colombia provide a compelling case that glyphosate spraying has been a
significant cause of illness in the region studied. Some of the reports in
Colombia, potentially related to glyphosate, are similar to those reported in
the literature and by California. These cases report irritation to skin, eyes, a
respiratory passages and suggesting that the Cosmo-Flux 411F added to the
glyphosate in Colombia has little or no effect on the overall toxicity of the
formulated product. Colombia. Prospective tracking of reports of health
complaints, documenting times of exposure and onset of symptoms, are recommended
during future spray operations to evaluate any potential health effects and
ameliorate or prevent their occurrence.
References
Acquavella JF, Weber JA,
Cullen MR, Cruz OA, Martens MA, Holden LR, Riordan S, Thompson M, Farmer D.
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Arbuckle TE, Lin Z, Mery LS.
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Barbosa ER, Leiros da Costa
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Hindson TC, Diffey B. 1984a.
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Hindson TC, Diffey BL.
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Hung DZ, Deng JF, Wu TC.
1997. Laryngeal survey in glyphosate intoxication: a pathophysiological
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Jackson JR. 1988. Toxicity
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Jamison JP, Langlands JH,
Lowry RC. 1986. Ventilatory impairment from pre-harvest retted flax. Br J Ind
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Jauhiainen A, Rasanen K,
Sarantila R, Nuutinen J, Kangas J. 1991. Occupational exposure of forest workers
to glyphosate during brush saw spraying work. Am Ind Hyg Assoc J 52:61-64.
Kageuka M, Hieda Y, Hara K,
Takamoto M, Fukuma Y, Kashimura S. 1988. Analysis of glyphosate and
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Lee HL, Chen KW, Chi CH,
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Lin CM, Lai CP, Fang TC, Lin
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glyphosate herbicide.
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Edwards IR. 1991. Intentional self-poisoning with glyphosate-containing
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Pushnoy LA, Avnon LS, Carel
RS. 1998. Herbicide (Roundup) pneumonitis. Chest. 114(6):1769-71.
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JS, Yang SF, Goo TS, Wang SH, Chen CL, Sanford TR. 1991. Acute poisoning with a
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WJ, Chung HM, Deng JF. 1991. Taiwan National Poison Center survey of
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1):117-65.
SECTION 4. Ecological Risk Assessment for the use of Glyphosate Herbicide
as Part of the U.S. Supported Aerial Eradication Program of Coca in Colombia.
I Introduction
At the request of the
Department of State (DoS), the Office of Pesticide Programs (OPP) of the U.S.
Environmental Protection Agency has developed an ecological risk assessment for
the aerial coca eradication program in Colombia. The DoS met with members of OPP
on April 18, 2002 to provide information on exposure and use of the glyphosate
tank mixture for aerial eradication of illicit coca in Colombia. This assessment
is based on the information provided in that meeting and in the appendix
included in the formal request from the Secretary of State. The eradication
program includes the use of a spray mixture of a glyphosate formulation, an
adjuvant (Cosmo-Flux 411F) and water. The glyphosate tank mixture is applied
aerially as a foliar application in certain provinces within Colombia.
II Background
Approach to Environmental
Fate and Ecological Risk Assessments of Pesticides
Before a pesticide can be sold in the United States, the Agency requires
pesticide companies which request product registrations in the U.S. to perform
certain required environmental fate and ecological effects studies and to submit
the resulting data. OPP uses the environmental fate studies to assess potential
environmental exposure; data requirements are listed in the regulations (40 CFR
§158.290). The ecological effects studies are used to assess potential toxicity
to non-target organisms; data requirements are established in 40 CFR §158.490
(Terrestrial and aquatic organisms data requirements), §158.540 (Plant
protection data requirements), and §158.590 (Nontarget insect data
requirements).
All non-target terrestrial
and aquatic animal toxicity studies, and aquatic plant studies, are performed
using the technical grade active ingredient (TGAI). Non-target terrestrial plant
toxicity tests are performed with pesticide in a formulated product (as sold to
users). Aquatic fish and invertebrate toxicity studies using formulated product
are also required if the use of the formulation is expected to lead to transport
to water bodies, either directly or through runoff. The potential exposure and
toxicity of each pesticide are considered to characterize the potential of
ecological risk.
The present environmental
fate assessment is based on regulatory environmental fate studies submitted to
the Agency to support the registration of glyphosate salts and their formulated
pesticide products. These studies were conducted under Good Laboratory Practices
(GLP), as required under the Federal Insecticide, Fungicide, and Rodenticide Act
(FIFRA). The studies used in the assessment have been deemed acceptable and have
served to generate previous environmental and ecological risk assessments for
glyphosate.
The number and types of
environmental fate studies required for each pesticide depends on its proposed
use pattern (terrestrial, aquatic, forestry, indoors, greenhouse). The required
studies consist of a series of core laboratory studies for all pesticides and
field dissipation studies for pesticides used on outdoor crops
(terrestrial/aquatic), non-crops (terrestrial/aquatic), and forestry. Each study
provides specific data that, together with the physical and chemical properties
of the pesticide, are then combined to produce an integrated environmental fate
assessment and to identify the potential of the pesticide to leach to
groundwater, and/or reach surface water, and/or bioaccumulate in aquatic
organisms. The data are also used as input parameters in models to estimate
exposure concentrations in the environment. Monitoring data, if available, are
also incorporated into the assessment.
The limited number of
species and environmental systems tested can introduce a degree of uncertainty
when attempting to extrapolate the data outside the experimental conditions of
the studies, such as different soils, geographical regions, and ecosystems. As
part of the overall risk characterization of a pesticide, the Agency also
identifies uncertainties associated with the available data and those introduced
by the assumptions needed to estimate concentrations using models.
III Ecological Risk
Assessment
Glyphosate
Terrestrial
The Agency does not expect
any risk to birds and mammals based on dietary exposure to active ingredient
glyphosate. Acute avian dietary studies using bobwhite quail and mallard ducks
resulted in no mortality at concentrations up to 5200 ppm, and no reproductive
effects were seen up to 1000 ppm, the highest levels tested. Toxicity tests
involving feeding or direct contact of honey bees to glyphosate also resulted in
no mortality at the highest rate tested (100 micrograms/bee). Acute LD50
values could not be established in oral and dermal mammalian studies at
concentrations up to and including 5000 mg/kg, and chronic mammalian effects
were only seen in a series of studies at 1000 mg/kg/day or higher. The Agency
waived the requirement for an acute inhalation study for mammals with active
ingredient glyphosate since no respiratory or systemic toxicity was seen
following subchronic inhalation exposure in rats.
Risk to non-target
terrestrial plants is likely from exposure to
glyphosate as a result of its use in the coca eradication program. Glyphosate is
a foliarly applied, broad spectrum herbicide effective at very low exposure
rates. Vegetative vigor studies for North American crops reviewed by the Agency
in 1999 indicate that 25% of exposed plants can be damaged by exposure to
glyphosate applied at rates as low as 0.07 lb ai/A.
Table 1. Vegetable Vigor
Toxicity of Glyphosate Wettable Powder to US Crops
|
|
EC25
|
NOEL |
Cucumber |
phytotoxicity |
0.074 |
0.049 |
Lettuce |
dry weight |
0.217 |
0.148 |
Oilseed rape |
phytotoxicity |
0.098 |
0.049 |
Okra |
dry weight |
0.172 |
0.049 |
Radish |
phytotoxicity |
0.235 |
0.148 |
Soybean |
dry weight |
0.126 |
0.049 |
Sugarbeet |
" |
0.277 |
0.148 |
Corn |
phytotoxicity |
0.227* |
0.148 |
Oat |
dry weight |
0.201 |
0.148 |
Purple nutsedge |
" |
0.805* |
0.445 |
Winter wheat |
" |
0.176* |
0.049 |
*Determined by linear interpolation.
The application rate of
glyphosate recommended by the State Department for the coca eradication program
is 3.34 lb ai/A in acid equivalents. This is well above the rates listed in the
table above. AgDrift modeling of potential spray drift from the use in Colombia
(detailed below) simulates that non-target plants hundreds of feet away may be
exposed to a fraction of this glyphosate application. Based on the toxicity data
for North American crops, AgDrift indicates the possibility that 50% of young
crop plants would be expected to show measurable reductions in dry weight
from150 to nearly 600 feet downwind (depending on spray and wind conditions).
Some affected plants would likely recover while more sensitive plants may die,
have reduced reproductive success, or reduced yields (crop plants).
Aquatic
Laboratory studies indicate
glyphosate is slightly toxic to fish, invertebrates and aquatic plants. The
lowest resulting acute LC50 values (concentrations at which half the
test animals died) were in parts-per-million (ppm) for active ingredient
glyphosate. For instance, the most sensitive freshwater fish (fathead minnow)
had an LC50 of 85 ppm, while chronic effects were not seen in another
study at the highest test concentration of 26 ppm. The EC50 (level at
which adverse effects are seen in half the test animals) for the freshwater
invertebrate Daphnia magna was 134 ppm, and the chronic NOEL 50 ppm.
OPP exposure models indicate
that surface-water exposure in the parts-per-billion could be expected from the
use on coca. OPP also considered a more conservative exposure scenario of the
direct application of 3.75 lb acid eq./acre of glyphosate to a 1-acre, 6-foot
deep pond2. The calculated maximum
concentration of 230 ppb is well below the glyphosate toxicity values measured
for aquatic organisms in the laboratory. Therefore, aquatic organisms should not
be at risk from exposure to glyphosate. The environmental fate assessment which
is the basis of this exposure calculation is described in the following section.
2Salts of glyphosate (isopropylamine,
diamine, and trimesium) are registered in the United States for a wide variety
of agricultural and non-agricultural uses. All of the salts of glyphosate
generate the "free acid of glyphosate" (glyphosate acid), the actual
herbicide-active chemical. The glyphosate acid equivalents vary from salt to
salt to salt, as it depends on the ratio of the molecular weight of the
glyphosate free acid to that of the salt. For this reason, application rates are
generally expressed in terms of "glyphosate acid equivalents" when estimating
exposure concentrations of glyphosate in water and soil. The ratio of glyphosate
acid to the glyphosate isopropylamine salt is 0.75. Thus, each pound of this
salt is equivalent to 0.75 pounds of glyphosate acid (or 1 g of the salt is
equivalent to 0.75 g of the acid)
It is possible that much
greater exposure could occur from direct overspray of water bodies much smaller
than a 1-hectare, 6-foot deep pond, but such simulation is not a standard
component of Agency risk assessments. The product label of the specific
glyphosate product DoS indicates is being used against coca, and the DoS
application guidelines, prohibit direct overspray of water bodies. It is
possible that some ecologically important water bodies too small to appear on
maps could be sprayed directly in a project as large as the coca eradication
program. EPA has registered other glyphosate products for direct application to
aquatic sites to kill undesirable vegetation.
Freshwater aquatic plants
also seem unlikely to be at risk from exposure to active ingredient glyphosate.
Submitted studies resulted in EC50 values of 12.5 ppm for green algae
(Selenastrum capricornatum), 21.5 ppm for duckweed (Lemna gibba)
and 38.6 ppm for the freshwater diatom Navicula pelliculosa. These values
are well beyond the 230 ppb exposure calculated for direct overspray in the pond
simulation described above.
Risk Specific to
Formulations of Glyphosate
Ecological toxicity studies
submitted to EPA for some of the formulations of glyphosate products that EPA
has registered have shown them to be more toxic than glyphosate alone. The
results of these studies indicate that the formulations will pose a risk
primarily to non-target plants, as described above. For instance, the minimum
bluegill sunfish LC50 of 5.8 ppm reported for a 41.8% glyphosate
formulation in EPA’s glyphosate reregistration eligibility document (RED, 1993)
is 20 times more toxic than the bluegill sunfish LC50 observed for
technical glyphosate, but is still much higher than exposure levels expected in
the environment. The bluegill sunfish LC50 for a test with surfactant
MONO818 by itself was 1.0 ppm.
The risk to non-target
terrestrial and aquatic animals from formulated glyphosate used for coca
eradication is uncertain because the Agency does not have relevant toxicity data
for the Colombian formulation, nor for the adjuvant Cosmo-Flux 411F. An adjuvant
is a subsidiary ingredient or additive in a mixture that adds to the
effectiveness of the primary or active ingredient. Adjuvants are most commonly
added to tank mixes of pesticide products before they are applied. Further
discussion is provided in the Health Effects Division’s assessment of the coca
eradication program.
Potential Spray Drift of
Glyphosate
The AgDrift model (version
2.01) was used to estimate downwind deposition of aerial applications of
herbicide sprays during coca eradication efforts. The aerial part of the AgDrift
model, which was used in this assessment, was developed from USDA Forest Service
models designed to estimate deposition of forestry applications. The model has
been the subject of a Scientific Advisory Panel (SAP) meeting3 and showed a good correlation with field trial data of
downwind deposition. Reviews and descriptions of AgDrift have been published.4
AgDrift uses a number of
input parameters associated with the application equipment and the meteorology
during application in calculating deposition levels. An attempt was made to
enter important input parameters appropriate for coca eradication applications
in Colombia as described by the Department of State (DoS) in their presentation5 to the Office of Pesticide Programs (OPP) or in documents
provided by DoS to OPP. Many input parameters in AgDrift do not greatly affect
deposition levels and a number of default inputs were used for these parameters.
The inputs considered to be more important in determining drift levels that were
used to model coca eradication spraying are listed in Table 1 below.
3http://www.epa.gov/scipoly/sap/1997/december/spraydrift.htm
4Hewitt AJ, DR Johnson, JD Fish, CG
Hermansky, and DL Valcore. 2002. Development of the Spray Drift Task Force
database for aerial applications. Environmental Toxicology and Chemistry. 21(3) pp.
648-658.Teske ME, SL Bird, DM Esterly, TB Curbishley, SL Ray, and SG Perry.
2002. AgDRIFT: A model for estimating near-field spray drift from aerial
applications. Environmental Toxicology and Chemistry. 21(3) pp. 659-671. Bird
SL, SG Perry, SL Ray, and ME Teske. 2002. Evaluation of the AGDISP aerial spray
algorithms in the AgDRIFT model. 2002. Environmental Toxicology and Chemistry.
21(3) pp. 672-681.
5April 18, 2002. Crystal City, Arlington,VA.
There are a number of
general uncertainties associated with AgDrift modeling to estimate spray drift
from coca spraying in Colombia. The AgDrift model is intended to represent a
flat area with uniform vegetation while coca cultivation is reported to occur in
some instances on irregular topography with scattered trees and shrubs. The
AgDrift model is not intended to model spray drift under very stable atmospheric
conditions (e.g. temperature inversions). Although coca eradication efforts
attempt to avoid these conditions they can be difficult to detect.
Table 1. AgDrift model
(version 2.01) inputs used to model spray drift deposition from coca eradication
spraying in Colombia.
Parameter |
Input |
Comment |
Aircraft |
Air Tractor |
The spray program is reportedly buying AT-802A aircraft for spraying operations. The AT-802A is heavier than the currently used Ayers T-65 Thrush which may result in slightly higher drift levels. |
Spray volume |
2.53 gal/acre |
Reported in (1) |
Nonvolatile rate |
5.49 lbs/acre |
Calculated from values reported on p. 4 in
(1): |
Droplet spectrum |
ASAE medium or ASAE very coarse to extremely coarse |
In (1) the droplet size spectrum is reported to have a volume median diameter of 300 to 1,500 microns. This is a large range for one of the most important factors in estimating off-target drift. Two categories of droplet size spectrum were chosen to represent the range. ASAE medium sprays have a VMD of approximately 300 microns. The ASAE very coarse to extremely coarse is the coarsest ASAE spray available in AgDrift 2.01with a VMD of 520 microns. It was not stated if droplet size was measured under application conditions. In the presentation at OPP offered by the DoS the VMD during application was said to be 200 to 300 microns. |
Wind speed |
3 & 10 mph |
Reference (1) p.6 states missions are canceled if wind speed measured at the airport is above 10 mph. Wind speed at the target site may vary but 10 mph was used as the best available input for modeling. |
Relative humidity |
75% |
Reference (1) p.6 states missions are canceled if relative humidity measured at the airport is above 75%. Relative humidity at the target site may vary but 75% was used as the best available input for modeling. |
Temperature |
90 degrees F |
Reference (1) p.6 states missions are canceled if temperature measured at the airport is above 90 degree F. Temperature at the target site may vary but 90 degree F was used as the best available input for modeling. |
Release height |
100 ft |
Reference (1) p. 6 states the altitude above spray targets is normally less than 100 feet. This value was used as the best available input for modeling. |
Spray lines |
4 |
Based on video of spraying operations with multiple aircraft, the number of spray lines used in modeling was 4. |
(1) Chemicals Used for the
Aerial Eradication of Illicit Coca in Colombia and Conditions of Application. An
undated, unsigned, 9-page document provided to OPP by the State Department.
In addition to the general
uncertainties above, there are also uncertainties associated with the inputs
used for modeling the spray applications. Droplet size is one of the most
important parameters affecting drift of pesticides. There is uncertainty as to
the droplet size spectrum used in aerial coca spraying. Documentation supplied
by the DoS6 describes the droplet size used in
terms of the volume median diameter (VMD) which is the droplet size for which
half of the volume of spray is contained in droplets with smaller diameter and
half of the spray is contained in droplets of larger diameter. The VMD was
stated to range from 300 to 1500 microns which is a wide range. In the DoS
presentation the VMD was stated to be 200 to 300 microns during application
conditions. In addition to the wide range of VMD values presented, VMD is not a
good descriptor of droplet size spectra for estimating spray drift. Spray drift
is predominately associated with finer sprays and VMD does not define the amount
of small droplets contained in spray. Although specific data on droplet size
under application conditions was not provided, it is unlikely that very coarse
sprays would be achievable due to shearing effects of releasing droplets at high
airspeeds. Large droplets released into the turbulence created by an aircraft
traveling in excess of 120 mph tend to break into smaller more driftable
droplets.
6Chemicals Used for the Aerial
Eradication of Illicit Coca in Colombia and Conditions of Application. An
undated, unsigned, 9-page document provided to OPP by the State Department.
Other uncertainties
associated with inputs include inputs for meteorology and release height.
AgDrift modeling requires site-specific inputs for meteorology. In coca
eradication efforts (as well as agricultural applications in the US) wind speed,
temperature and humidity are measured at the airport which may not be
representative of these parameters at the application site. The applicator is
ultimately given the responsibility of determining if conditions at the target
site are acceptable. DoS reports that the coca eradication program selects
experienced applicators for spray missions with the expectation they will better
be able to identify unacceptable conditions and make applications within
specified parameters.
In order to capture the
range of deposition values expected during coca eradication applications,
AgDrift was run with two droplet size spectra and at two wind speeds. The
droplet size spectra were extremely coarse to very coarse and medium. The
definitions refer to the American Society of Agricultural Engineering (ASAE)
Standard 572 definition of droplet size spectra. The wind speeds used were 3 mph
and 10 mph. AgDrift was run in tier 3 to estimate downwind depositions shown in
Figure 1 below.
Figure 1 shows the lowest
levels of drift are associated with applications using the extremely coarse to
very coarse sprays at a 3 mph wind speed. The highest levels of drift are
associated medium sprays at wind speeds of 10 mph. Downwind deposition levels
from coca eradication spraying is likely to be bounded by these estimates. The
effect level for 50% of young plants@ is based on glyphosate toxicity studies on ten crop plants. At the level
corresponding to approximately 11% of the application rate, 50% of plants
species would be expected to show measurable reductions in dry weight. Of the
affected plants some would likely recover while more sensitive plants may die,
have reduced reproductive success, or reduced yields (crop plants).
V. Environmental Fate and
Transport Assessment of Glyphosate
Integrated Environmental
Fate Assessment- Summary
The major route of
transformation of glyphosate identified in laboratory studies is microbial
degradation. In the field, glyphosate dissipation appears to correlate with
climate, being more persistent in cold than in warm climates. Dissipation of
glyphosate in Colombia may therefore be more rapid than in the U.S. Glyphosate
was not observed in laboratory studies to break down by abiotic processes such
as hydrolysis and direct photolysis.
Glyphosate is very soluble,
and has a low potential to volatilize, but adsorbs strongly to soils and
sediments. Therefore, glyphosate does not have a high potential to leach to
ground water or reach surface water as dissolved runoff. However, glyphosate has
the potential to contaminate surface water as a result of residues adsorbed to
soil particulates suspended in runoff water. Offsite exposure is also possible
due to spray drift or inadvertent direct overspray.
Physical and chemical
properties of glyphosate acid
Glyphosate belongs to the
glycine family of herbicides. Glyphosate is a phosphono derivative of glycine,
the simplest of all of the amino acids. It works as an herbicide by inhibiting
the enzyme A5- enolpyryl-shikimate-3-phosphate@ synthase (i.e., it is an ESPS
inhibitor). Glyphosate is not an organophosphate and it is not an inhibitor of
cholinesterase activity.
Chemical name: N-(phosphonomethyl)glycine
Chemical Abstracts
Registry Number:
1071-83-6
Chemical structure:
Physical and chemical
properties of glyphosate relevant to the environmental fate assessment
Physical and chemical property |
|
Molecular formula |
C3H8NO5P |
Molecular weight |
169.07 |
Solubility in water |
12,000 mg/L 25E C (very soluble) |
Vapor pressure |
4.3 x 10-10, mmHg at 25E C (doesn=t readily volatilize) |
Henry=s Law Constant |
9.6 x 10-17, atm-m3/mole, estimated at 25E C |
n-Octanol-water partition coefficient (Kow) |
-4.0 |
pKa |
Glyphosate is a zwitterion |
Transformation,
persistence and transport in soils
The major route of
transformation of glyphosate in soils is microbial degradation. In laboratory
studies in soils incubated under aerobic conditions, 14C-labeled
glyphosate degraded with half-lives ranging from 1.85 to 5.4 days in two sandy
loam soils, and 2.06 days in a silt loam. These studies were conducted in the
absence of light and at 25E C. The major degradate that formed in these soils was
aminomethyl phosphonic acid (AMPA), which reached a maximum of ca. 29% at 40
days, but declined afterwards. After 1 year, $70% of the applied radioactivity was
found as 14CO2, indicating that the ultimate fate of
glyphosate and AMPA is mineralization (i.e., formation of CO2 and
inorganic carbonates and bicarbonates). Photolysis on soil is not a degradation
route for glyphosate, as the half-lives under both irradiated and dark
conditions were 6.6 days and any degradation that occurred during the studies
was likely to be microbial.
Batch-equilibrium adsorption
studies in a wide range of soils and sediments from the US and United Kingdom
have shown that glyphosate and AMPA adsorbed strongly to soils, with adsorption
coefficients (Kads) ranging from 9.4 to 700 mL/g. Therefore,
glyphosate has a low potential to leach to groundwater or reach surface water by
runoff, but may enter surface water through soil erosion.
Terrestrial field
dissipation studies conducted with a formulation of the non-radiolabeled
isopropylamine salt at an application rate of 10.7 lb of salt/acre (7.95 lb acid
equivalent/acre) showed that dissipation (i.e., transformation plus transport)
was slower in colder than in warmer climates. The reported half-lives at each
site were 2.9 days in Texas, 13 to 20 days in Georgia, California and Arizona,
127 days in New York, and 140 days in Iowa. Glyphosate and AMPA were found
predominantly in the 0 to 6 inch layers, indicating that they are not potential
leachers. All of these studies were conducted with the formulation applied
directly to soil in bare ground plots. Glyphosate is a foliar herbicide that is
not applied directly to soils and would only reach soil by wash-off from
foliage. Therefore, direct application to soils in bare ground plots represent a
worse case of glyphosate use.
The low vapor pressure of
glyphosate (4.3 x 10-10, mmHg at 25E C and 1.8 x 10-10,
mmHg at 45E C) suggests
that it has low potential to volatilize from soils.
Transformation,
persistence, and transport in water
Laboratory studies suggest
that abiotic hydrolysis (i.e., hydrolysis in the absence of microorganisms) is
not a primary degradation pathway for glyphosate. Glyphosate remained stable for
at least 30 days in sterile aqueous buffered solutions of pH 5, 7 and 9 that
were kept in the dark at 25E C. Buffered solutions of glyphosate were stable to
sunlight, suggesting that direct photolysis is not a likely degradation pathway
for glyphosate. EPA has no data at this time to assess any contribution of
indirect photolysis in natural waters.
The half-life of glyphosate
in a silty clay loam sediment incubated under anaerobic conditions (flooded plus
a nitrogen atmosphere) was estimated as 8.1 days and 199 days in a water-clay
loam sediment system. Most of applied radioactivity was found in the sediment
phase. The major metabolite was AMPA, which also remained associated with the
sediment. The observed half-live in an aerobically incubated silty clay loam
sediment was 7 days.
Aquatic field dissipation
data showed that the half-life of glyphosate in water used as irrigation source
was 7.5 days (farm pond in Missouri, 408816-01). In Michigan, Georgia, and
Oregon pond and stream water systems, glyphosate dissipated rapidly immediately
after treatment. Accumulation was higher in the pond than in the stream
sediments (415528-01).
The low Henry’s Law constant
of glyphosate suggests that glyphosate is not likely to volatilize from water.
Given the strong adsorption to sediments, glyphosate is most likely to be
associated with the sediment. The very low n-octanol -water partition
coefficient is indicative that glyphosate is not likely to bioaccumulate in
aquatic organisms
Dissipation in a forestry
environment
Residues of an aerially
applied glyphosate product at a rate of 3.75 lb of acid equivalents/acre
declined rapidly from tree foliage in less than 1 day at the Michigan and
Georgia sites and less than 14 days at a site in Oregon. The rate of dissipation
in the foliage (wash-off) correlated with the amount of rainfall and leaf drop,
which also determines the movement of glyphosate and AMPA through the forest
ecosystem. The average half-life for overall dissipation from the forest
ecosystem was 100 days for glyphosate (35 to 158 days) and 118 days for AMPA (71
to 165 days). In all cases, the maximum combined residue of glyphosate and AMPA
in soil was less than 5 ppm , but the amount of residues declined with time
(MRID 415528-01).
VI. Risk Characterization
The ongoing use of a
glyphosate spray for coca eradication is likely to pose a risk to non-target
plants. Vegetative vigor toxicity laboratory tests performed using a formulated
glyphosate product (glyphosate acid WP 48.3%) on North American crops indicated
toxicity to terrestrial plants with applications of less than 1.0 lb of active
ingredient per acre (lb ai/acre) (Table I). The State Department proposes to use
a rate of 3.34 lb acid equivalents/acre for direct, aerial application to coca.
A second application is possible if fields are replanted, or the first is
determined after 3 to 6 months to have been inadequate. The product reported by
DoS as used in Colombia has a formulation which matches the formulation of a
product that is registered, but not used, in the United States.
AgDrift modeling of
potential spray drift indicates that non-target plants hundreds of feet away may
be exposed to a fraction of this glyphosate application. Based on the toxicity
data for North American crops, AgDrift indicates the possibility that 50% of
young plant crops would be expected to show measurable reductions in dry weight
from 150 to nearly 600 feet downwind (depending on spray droplet size and wind
conditions). As detailed below, there are several hundred non-target terrestrial
plant incident reports in the Agency’s Ecological Incident Information System
(EIIS) database connected with the use of glyphosate products.
There is uncertainty whether
crops or other plants in Colombia, whether similar to crops tested in the United
States or not, would be affected similarly at the same exposure levels. However,
since glyphosate is an effective, broad spectrum herbicide, risk to non-target
plants outside of the application zone would be expected. The Agency’s EIIS
database includes several hundred reports of possible non-target plant incidents
in the United States attributed to use of glyphosate.
This use of the active
ingredient glyphosate itself would not pose a significant direct risk to
terrestrial or aquatic animals, although temporary secondary adverse effects
from the loss of habitat in the spray area may occur. Neither acute nor chronic
adverse effects were observed in mammalian and avian laboratory toxicity tests
using the active ingredient alone. Mortality was observed in fish and aquatic
invertebrate studies. However, the resulting acute LC50 values
(concentrations at which half the test animals died), and lowest effect levels
for chronic effects, were in parts-per-million. Toxicity endpoints for aquatic
plants also ranged from 0.85 to 39.9 ppm. Considerably lower surface-water
exposure, in the parts-per-billion, could be expected from the use on coca using
runoff simulations from Agency exposure models. The Agency considered an even
more conservative scenario, estimating the concentration that would result from
the direct application of 3.75 lb acid eq./acre of glyphosate to a 1-acre,
6-foot deep pond. The calculated maximum concentration of 230 ppb is well below
the toxicity values measured for aquatic organisms in the laboratory.
It is possible that much
greater exposure could occur from direct overspray of water bodies much smaller
than a 1-acre, 6-foot deep pond, but such simulation is not a standard component
of Agency risk assessments. It is possible that some ecologically important
water bodies too small or ephemeral to appear on maps could be sprayed directly
in a project as large as the coca eradication program.
There are several aspects of
an ecological risk assessment which, while included as a regular part of the
U.S. registration process, are not relevant to the use of glyphosate on coca. In
considering the risk of a chemical to terrestrial or aquatic animals in the
United States, the Agency has set levels of concern (LOCs) at between 5 to 20%
of the acute toxicological endpoints for further consideration of risk to
endangered species, or eligibility of a chemical for Restricted Use (application
permitted only by Certified Pesticide Applicators.) Our document does not
include endangered species because the Agency lacks information on the species
which might be present in areas of spraying. In addition, the Health Effects
Division determined that results of mammalian toxicology studies did not warrant
the establishment of a chronic toxicological endpoint for the calculation of a
Reference Dose (RfD, a reference endpoint for human health risk assessment ) for
glyphosate. Since there is not a chronic endpoint, a drinking water exposure
assessment is not necessary for the use of glyphosate on coca.
Although the measured
toxicity and estimated exposure indicate that only non-target plants are likely
to be adversely affected by the use on coca, there are important uncertainties
that should be considered. One of these, which was emphasized by the Amazon
Alliance in a memo to the Agency, is the extrapolation of North American data to
the conditions and wildlife found in Colombia. The toxicity of a pesticide to
different classes of animals and plants can vary widely among species within an
individual ecosystem. The Agency uses the test species as surrogates for other
North American species not tested, but has little experience with tropical flora
and fauna. Similarly, laboratory and field estimates of the environmental fate
of pesticides, including potential surface- water contamination, are performed
with North American soils, hydrology and climate data.
The potentially most
important uncertainty in this risk assessment concerns differences in the
formulation and tank mix for use in Colombia from those used in the United
States. Toxicity studies indicate that U.S. formulations of glyphosate are more
toxic to non-target animals than the technical product alone, but not toxic at
levels of expected exposure. However, none of the ecological effects studies
submitted to or encountered by the Agency for glyphosate were performed with the
formulation that the DoS has indicated is used in Colombia, which may contain
different types of cationic surfactants than those in formulations for which the
Agency has data. Consultant Jeremy Bigwood presented a literature search of over
200 citations to the Ecuadorian Minister of the Environment in March 2002,
stating that A(t)here have been NO scientific
investigations on the past or present formulations being used in Colombia.@
In addition, the Agency does
not have ecological toxicity information on adjuvant Cosmo-Flux 411F, which is
neither manufactured nor sold in the United States. There is some inconsistency
in the description of Cosmo-Flux in the two available labels, in Spanish and in
English. However, all of the individual ingredients (surfactants) which comprise
the adjuvant are substances with low oral and dermal mammalian toxicity. The
toxicity of the blend of these surfactants is not known; although the Agency
often requires formulation toxicity data for non-target plants and aquatic
organisms, tank-mix adjuvants are not required to be included in these studies.
Reports From External
Sources
The effect of Cosmo-Flux
411F or its individual ingredients on non-target organisms is unknown, although
Mr. Bigwood suggests some possible effects in his report to the government of
Ecuador. Mr. Bigwood cites studies from the Western Australia Department of
Environmental Protection (WADEP) as indicating that a formulation equivalent to
that which the Department of State has indicated is used in Colombia Acan be acutely toxic to adult frogs
and tadpoles at the recommended application rates (1.8 to 5.4 kg/ha).@ The Agency’s tox database cites LC50
values for two Australian frog species (Crinia insignifera and Litoria
moorei) of 40 and 8 ppm, respectively, presumably from the same studies.
Such concentrations are greater than those likely to occur from transport of
glyphosate in runoff to ponds. These concentrations might be possible for frogs
exposed by direct overspray, such as tree frogs. However, the Agency does not
have a method for estimating the possible dietary intake of pesticides for tree
frogs; the Agency’s model for dietary exposure of terrestrial animals is based
on agricultural field data collected in the United States. Extrapolation of
toxicity to Australian frog species to Colombian species includes significant
uncertainty.
Suggestions of risk to other
organisms in Mr. Bigwood’s report are less specific. This report states that
(t)oxicity of glyphosate formulations in riverine systems is not merely limited
to fish, but also to amphibians, insects, crawfish and water fleas, and
undoubtedly to other species found in rivers and other bodies of water.@ This is followed by a discussion of
toxicity values for a surfactant other than Cosmo-Flux 411F . As described
above, while aquatic exposure to glyphosate itself (or U.S. formulations) is not
likely to pose a risk to aquatic animals and plants, data on the toxicity of
tank- mix adjuvant Cosmo-Flux 411F to these organisms would be required to
assess formulation and tank-mix risks. Tank-mix ecological toxicity data are not
routinely provided in the U.S. pesticide registration process.
The Agency would need to
obtain and review literature studies cited in Mr. Bigwood’s report in order to
comment on other suggested risks. Mr. Bigwood suggests that glyphosate enhances
the growth of pathogenic fungi according to several research papers.@ Based on the titles of the papers,
most of the studies cited concern the effect of fusarium fungi on glyphosate
efficacy. The Agency cannot comment on the magnitude of this effect without
reviewing the data, nor on the potential for risk from this effect. The effects
of pesticide applications on microbiota is not a standard component of the
Agency’s risk assessments.
Incident data
US Incident Data
There are several hundred
non-target terrestrial plant incident reports in the Agency’s Ecological
Incident Information System database connected with the use of glyphosate
products. This is consistent with the risk assessment above, which suggests that
the efficacy of glyphosate is such that non-target plants hundreds of feet away
could be at risk from glyphosate in spray drift. The variety of crops,
ornamentals and trees included in the EIIS reflect the wide spectrum of
glyphosate efficacy.
There are a small, limited number of reported incidences to fowl, fish
and a dog allegedly resulting from label use of glyphosate products. Further
analysis of the data on the actual incidence report forms indicates that other
factors or other pesticides may explain the adverse effects. For instance, one
incident was apparently due to overstock and improper oxygen levels in a catfish
pond, and another to a spill of several barrels of Roundup directly into a
creek. Another fish kill was more likely attributable to diuron runoff into a
pond than to glyphosate exposure. Although glyphosate was associated with these
incidents, the fact that other conditions or pesticides were likely responsible
is consistent with the fact that glyphosate has very low mammalian, avian and
aquatic acute and chronic toxicity.
Only one incident appears to be attributable to glyphosate, involving 2
iguanas that ate dandelions apparently sprayed with a Roundup product. However,
the reptiles exhibited signs of neurological effects (shock, depression and
tremor) which are not generally associated with glyphosate toxicity and which
may be due to the inert ingredients in the formulation. The Agency does not have
any test protocols nor does it require toxicity testing on reptiles for any
pesticide. Thus, information on this class of animals in general is an
uncertainty.
Central and South American Incidents
Mr. Bigwood’s report for the Government of Ecuador states that exposure
to a dried formulation containing both glyphosate and a surfactant in Roundup
(the commercial product being used) caused the death of over 50%@ of several beneficial insect species. The report does
not indicate the level of exposure or the nature of the dried formulation@ that caused these effects. Therefore, the Agency
cannot comment on the relevance of these data to aerial spray of the
formulation. Mr. Bigwood cites a Los Angeles Times article in which Guatemalan
farmers contend that the discontinued poppy eradication program has devastated
the areas traditional agricultural base, particularly tomatoes and bees.
Honeybee oral and contact toxicity tests provided to the Agency using technical
glyphosate (active ingredient only, not the formulated product) could not
establish an LC50 at concentrations up to 100 micrograms per bee.
However, these studies cannot be used to rule out the possible toxicity of the
Colombian formulation and tank mix to beneficial insects.
The Amazon Alliance provided the Agency with a list of incidents in
Colombia which report adverse effects to crops and domesticated animals from the
use of glyphosate on illicit crops. The Agency cannot comment on the reliability
of these incident reports, because sufficient information isn't included for
each incident. The plant incidents are not inconsistent with the body of plant
incidents in the Agency's Ecological Incident Information System database.
However, the large animal incidents reported by the Amazon Alliance do not
appear to be consistent with glyphosate and glyphosate formulation toxicity data
submitted to and reviewed by the Agency.
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