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Atrazine's Assault on Health and
the Environment
Atrazine, introduced
in 1958, is the most widely used pesticide in the United States.
Between 70 and 90 million
pounds of the active ingredient
are used annually to combat weeds in agriculture, commercial, and domestic
areas. It is used on lawns, playing fields, roadsides and golf courses.
Atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) is
a chlorinated triazine herbicide used to control certain weeds in crops,
particularly corn – sorghum – sugarcane – pineapple
- macadamia nuts and citrus. Atrazine is the active ingredient in many
herbicide products including Aatrex, Atrataol, Gesaprim and Zeophos,
while it is a component of other herbicides including Alazine, Bicep,
Bullet, Extrazine, Prozin, Rastra, Stuazine, and Tomahawk.1,2
The largest producer of atrazine has been the Ciba-Geigy Corporation
that became Novartis, and is now Syngenta, the world's largest agribusiness
company with 6.3 billion dollars in sales of agrichemicals. Atrazine
is also manufactured
by E.I. duPont de Nemours & Co., Drexel Co., Oxon Italia, and Prodotti
Chimici. Around 1970, only 12 years after being introduced, farmers were beginning
to notice weed resistance to atrazine. By 1983 more than two-dozen weed species
showed resistance to atrazine, and to other herbicides as well.1-3
In spite of its wide use in this country, atrazine has been banned in most
western European countries, with France announcing a ban in 2001 due to atrazine's
presence in water and risks to human health.4
Environmental Impact
A major environmental concern is atrazine's mobility in soil and ground
water. It has been found in the groundwater of 24 states, some of which do
not even use the pesticide. The highest concentrations of atrazine were found
in the corn-belt states of Illinois, Indiana, Iowa, Nebraska, and Kansas. It
has been detected in 30 out of 33 samples of treated drinking water, indicating
that it is not eliminated by ordinary treatment technology. More expensive
activated charcoal filtration and ozonation are necessary for removing atrazine
and its metabolites from drinking water.1
Another concern of atrazine's presence in water is the possible production
of N-nitrosoatrazine (NNAT), a class of potent carcinogens. There is an increased
incidence of non-Hodgkin's lymphoma in Nebraska counties with nitrate-contaminated
wells, raising the question of a link. A study of rural ponds in Ontario, Canada,
found atrazine to be the most common contaminant from drift and run-off. A
study of 18 lakes in Switzerland found atrazine present in all 18, besides
being detected in rainwater.1
Atrazine molecules attach to dust particles and travel in clouds, fog and snow.
Atrazine has been detected in drinking water sources in France, Italy, the
Netherlands, Germany, the United Kingdom, Spain and Greece.1,2
Due to additional findings linking atrazine to increased health risks, the
US Environmental Protection Agency (EPA) attempted to reduce the amount of
atrazine in the water by requiring more detailed label instructions limiting
the sale and use of atrazine to certified applicators only, and requiring a
66' buffer zone between area of use and any surface water. The problem
is much more extensive and the herbicide more pervasive than previously recognized.5
Atrazine persists in soil from one growing season to the next. It degrades
into at least eleven metabolite products, some of which are as toxic as the
original, according to manufacturer, Ciba-Geigy.1
Atrazine's presence in water has been studied since 1981. In 1988 the
EPA finally called attention to the problem and began to investigate possible
adverse health effects of atrazine, and to reduce its presence in water.
Health Risks
The National Institute for Occupational Safety and Health acknowledges atrazine's
toxicity as a severe eye, and mild skin irritant. Chronic toxicity includes
diminished weight gain, increased irritability, and probable anemia in rats.
Studies with dogs demonstrated increased mortality; decreased food consumption;
increased liver, ovary, and heart weights (in females). Both sexes showed electrocardiographic
changes in the heart accompanied by detectable pathology.1
Atrazine's ability to disrupt endocrine function in lab animals is well-known.
Pregnant and nursing rats exposed to atrazine and one of its metabolites resulted
in slow maturation of the offspring's sexual organs. Offspring of both
sexes showed modified pituitary activity with strong inhibition of certain
hormone receptors and a reduction in weight. A survey of 856 Iowa municipal
water supplies (1986-1987) found levels of the herbicides - atrazine, metolachlor,
and cyanazine were each significant predictors of intrauterine growth retardation.1,3,6
Using technical atrazine (only the active ingredient, not formulated products)
research with lab subjects found dose-related breast tumors in females, testicular
tumors in males, increased incidence of cancers of the lymph system (leukemia,
lymphoma), increase in benign mammary tumors in males, and an increase in cancer
of the uterus of females.1
Women exposed to atrazine develop ovarian tumors 2.7 times more than non-exposed
women. Residents of eastern Nebraska exposed to atrazine showed an elevated
risk of non-Hodgkin's lymphoma. For over a decade the EPA has classified
atrazine as a possible human carcinogen (Class C) based on information of increased
incidence of mammary tumors in female rats.1
Prostate Cancer
Environmental illness expert, author, and respected champion of disease prevention,
Dr. Sherry Rogers warns that, "Atrazine, a common weed killer… has
caused enlargement of the prostate (hypertrophy)…, (and) has lowered
testosterone levels and caused depression by interfering with serotonin synthesis." She
admonishes that the epidemic use of pesticides has contributed to the increase
in prostate cancer over the last 20 years.7
The finger of suspicion now points to an atrazine manufacturing plant in Louisiana
where workers are suing their employer because the incidence of prostate cancer
appears to be nine times that of the general public. The Natural Resource Defense
Council (NRDC) is claiming Syngenta illegally suppressed its own study on atrazine
and prostate cancer among workers by withholding information from the EPA.
Documents obtained through the Freedom of Information Act indicate that Syngenta
was aware of prostate cancer among workers in the mid-1990s, but failed to
disclose this information to the EPA until 2001.8
In the late 1980s concerns arose about atrazine's potential to cause
cancer in humans. In spite of a decade's worth of documentation of cancer
cases at Syngenta's primary manufacturing plant, the EPA reversed its
previous stand which designated atrazine as a (Class C) probable human carcinogen,
and reclassified the chemical in June 2002 as "not a likely human carcinogen."8
Transsexual Frogs
Tyrone Hayes, a biology professor at the University of California at Berkeley,
has been collecting frogs since his youth in South Carolina. His current research
on frogs and atrazine has created quite a stir between environmental advocates
and industry. Frogs' permeable skin makes them unusually vulnerable to
environmental toxins. Scientists find it convenient to study the impact of
hormone mimicking chemicals on frog development because their transformation
from egg to tadpole is rapid and visible to the naked eye.2
Controversy over atrazine escalated in 1998 when Syngenta asked Hayes to study
the herbicide's safety. Hayes was using concentrations at one-thirtieth
the safe level set by the EPA for drinking water and it appeared that this
trace amount was creating hermaphrodites. He tested frogs and water samples
from Indiana, Wyoming, and Utah. His findings were first published in the Proceedings
of the National Academy of Sciences (Apr 2002) and in Nature (Oct 2002).2
Hayes theorizes the effect atrazine plays in frog abnormalities begins with
testosterone acting as a precursor to estrogen. In male frogs testosterone
causes their voice boxes to grow and their vocal sacs to develop. Atrazine
exposure in frogs switches on a gene that makes the enzyme aromatase, which
turns testosterone (male hormone) into estrogen (female hormone) causing frogs
to be demasculinized and feminized. Estrogen stimulates growth of ovaries,
eggs, and yolk. Under normal conditions male frogs do not make aromatase and
would not be turning testosterone into estrogen.2
Many experts are quick to point out that humans are not frogs, and that we
should not leap to conclusions regarding atrazine's negative effect on
sexual development. Other scientists, like Theo Colburn of the World Wildlife
Fund, and author of Our Stolen Future, point out that all species have similar
signaling systems and similar chemical reaction. For this reason testing medical
drugs on animals has become a standard procedure.2
Frogs spend more time in pesticide-laden waters than do humans, however, the
human fetus spends nine months in a watery habitat. Several studies of farm
families show that babies conceived in spring when pesticide runoff is highest
have much higher rates of birth defects than babies conceived at other times.2
When presented with Hayes' findings in August 2001, Syngenta was not
too pleased, and refused to acknowledge his work. No longer under contract
with Syngenta, Hayes continued research on his own. Syngenta then turned to
Texas Tech to repeat the frog experiments, in which almost no hermaphrodites
appeared. Lab conditions were not identical at Texas Tech. According to Hayes,
the water temperature was too cool, frog density too high, atrazine levels
not properly controlled, and diet was insufficient, thereby inhibiting gonadal
development making it difficult to recognize deformities.2
A point of major interest is that the Texas lab used glass tanks while Hayes
used plastic tanks.2 Chemicals in plastics are increasingly recognized as estrogen
mimics and endocrine disruptors in wildlife and in humans.
Whatever synergistic impact plastic chemicals might have on the negative effect
atrazine confers to frog development should not go unheeded. Human exposure
to plastic is ubiquitous, and for individuals in high risk areas of exposure
to atrazine the synergy may act as a double whammy, similar to tobacco and
asbestos exposure.
Plastic Chemicals are Endocrine Disruptors
The plastic versus glass containers jumps out as a possible major confounding
issue that should be addressed in future studies. Plastics are increasingly
recognized as endocrine disruptors. Some are estrogen mimics, while others
interfere with androgen (male sex hormones). Phthalates have been found to
cause birth defects and altered sexual development in lab animals by interfering
with normal hormone function. Tests on humans find phthalates present at
levels far higher than expected by the Centers for Disease Control and Prevention
(CDC).9
It is virtually impossible to avoid plastics in the modern world. Plastics
are everywhere – in disposable diapers and chewy toys, in Styrofoam cups
and food packaging, in water/soda/juice/baby bottles, even medical equipment,
and more.10,11
US Environmental Protection Agency
The EPA has finally acknowledged atrazine's increasing environmental
contamination and has announced what it considers "aggressive" measures
to protect drinking water. Environmental advocates criticize EPA's action
as too little too late. EPA's program will focus on 37 community water
systems with high levels of atrazine. Atrazine use will continue as usual,
while Syngenta, the manufacturer, collects "frequent monitoring data." If
contamination levels for atrazine or its metabolites exceed 37.5 parts per
billion (p/p/b) in eight of these water systems, further use of atrazine in
those watersheds will be prohibited.12 Once again, we have the fox guarding
the henhouse, the same fox accused of withholding prostate cancer information
from the EPA and from its own employees.
Furthermore, the EPA and Syngenta are working on an ecological monitoring agreement.
By October 2003 EPA plans to address the impacts of atrazine on amphibian development.
Professor Hayes' meticulous research has shown as little as 1 ppb of
atrazine interferes with frog sexual development.12 Will Hayes' work
be disregarded by more favorable, though questionable, outcomes from Texas
Tech?
Caroline Cox, editor of the Journal of Pesticide Reform, Eugene, Oregon, believes
the EPA could better protect environmental and public health by aggressively
cleaning up current contamination of rivers and streams by "showing farmers
successful techniques for growing corn without using atrazine."12
Updated information about atrazine is available from:
Jennifer Sass, PhD
Senior scientist with the Natural Resource Defense Council
(NRDC)
1200 New York Ave.,
NW, Suite 400
Washington, DC 20005 USA
202-289-2362
Fax: 202-289-1060
Email: jsass@nrdc.org
Citizens concerned about atrazine can submit comments to the EPA addressed
to:
Public Information & Records Integrity Branch
Information Resources & Services Division (7502C)
Office of Pesticide Programs
Environmental Protection Agency
1200 Pennsylvania Ave., NW
Washington, DC 20460-0011 USA
or email to opp-docket@epa.gov
Attention should be made to: Docket # OPP-2003-0072, Atrazine IRED, 68 Fed.
Reg. 9652 (Feb. 28, 2003).
Rose Marie Williams, MA
156 Sparkling Ridge Road
New Paltz, NY 12561
845-255-0836
Fax 845-255-5101
jwill52739@aol.com
References
1. Uhler, B., "Atrazine," Jrnl. Pesticide Reform, Vol.11,
No.4, Winter 1991.
2. Royte, E., "Transsexual Frogs," Discover, Feb 2003.
3. Snedecker, S, "The Ribbon," Vol.7, No.2, Cornell U.,
Spring 2002.
4. "France Bans Triazine Herbicides," www.safe2use.com/ca-ipm/01-11-16.htm.
5. After Silent Spring, NRDC, (212-727-2700), NY
6. Munger, R., et al, "Intrauterine Growth Retardation in Iowa
Communities with Herbicide-contaminated Drinking Water," Dept.
of Preventative Medicine & Env. Health, Univ. of Iowa, 12/02/97.
7. Rogers, S., MD, Total Health In Today's World, (800-846-6687)
Oct 1998.
8. NRDC, www.actionnetwork.org/campaign/ban_atrazine (5/2004:
link expired.) (Frogs.org).
9. Montague, P., "Here We Go Again," Rachel's Env. & Health
BiWkly, #708, (410-263-1584), Sept 14, 2000.
10. Williams, R.M., "Plastics: The 6th Major Food Group – Part
1, TLfDP, #210, Jan 2001.
11. Williams, R.M., "Plastics: The 6th Major Food Group – Part
2, TLfDP, #211/212, Feb/Mar 2001.
12. Cox, C., "EPA Announces 'Aggressive' Atrazine
Program," Jrnl. of Pesticide Reform, Vol. 23, No. 1, Spring 2003.
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