, October 8, 2009 (ENS) – The commonly used weed killer atrazine will undergo a new comprehensive evaluation to determine its effects - first on humans and later on amphibians and aquatic ecosystems, the U.S. Environmental Protection Agency announced Wednesday.
The most recent studies on atrazine and its potential association with birth defects, low birth weight, and premature births will be included in the year-long evaluation of the chemical's effects on humans.
To evaluate atrazine's potential cancer and non-cancer effects on humans, the EPA will engage the federal Scientific Advisory Panel established by the Federal Insecticide, Fungicide, and Rodenticide Act. The panel, composed of biologists, statisticians and toxicologists, serves as the primary scientific peer review mechanism for EPA's Office of Prevention, Pesticides and Toxic Substances. The panel will hold its first meeting on November 3.
Next September, at the end of this process, the EPA will decide whether to revise its current risk assessment of the pesticide and whether new restrictions are necessary to better protect public health.
Atrazine (Photo courtesy Kansas State U.)
Then, the EPA will ask the Scientific Advisory Panel to review atrazine's potential effects on amphibians and aquatic ecosystems.
One of the most widely used agricultural herbicides in the United States, approximately 70 million pounds of active ingredient are applied across the country every year. First registered for use in December 1958, atrazine can be applied before and after planting to control broadleaf and grassy weeds.
It is used primarily on corn, sorghum, and sugarcane, and is applied most heavily in the Midwest. To a lesser extent, atrazine is used on residential lawns, particularly in Florida and the Southeast.
"One of Administrator [Lisa] Jackson's top priorities is to improve the way EPA manages and assesses the risk of chemicals, including pesticides, and as part of that effort, we are taking a hard look at the decision made by the previous administration on atrazine," said Steve Owens, assistant administrator for EPA's Office of Prevention, Pesticides and Toxic Substances.
The Bush-era EPA decided to reregister atrazine for use in 2006. At that time, the EPA determined the chemical poses "no harm that would result to the general U.S. population, infants, children or other major identifiable subgroups of consumers."
Yet, studies by Dr. Tyrone Hayes at the University of California show that atrazine is an endocrine disruptor that interferes with reproduction and "assaults male sexual development." Dr. Hayes demonstrated that atrazine chemically castrates and feminizes male frogs at concentrations 30 times lower than levels allowed in water by the EPA.
"Atrazine induces breast and prostate cancer, retards mammary development, and induces abortion in laboratory rodents," says Dr. Hayes. "Studies in human populations and cell and tissue studies suggest that atrazine poses similar threats to humans."
Atrazine may affect pregnant women by causing their babies to grow more slowly than normal, according to the federal Agency for Toxic Substances. Research has also raised concerns about atrazine's potential as a multiplier that could increase toxic effects of other chemicals in the environment.
Owens said the EPA is now reconsidering its position on atrazine. "Our examination of atrazine will be based on transparency and sound science, including independent scientific peer review, and will help determine whether a change in EPA's regulatory position on this pesticide is appropriate," he said.
The EPA announced its new evaluation of atrazine less than six weeks after the Natural Resources Defense Council released a report that found the chemical in watersheds and drinking water throughout much of the United States.
"We don't need gender-bending chemicals in our water," said NRDC attorney Mae Wu. "While atrazine's makers like to talk about the pesticide's long-running history, we have learned a lot since it was introduced a half century ago."
"Studies point to significant concerns about this chemical's impact on wildlife, babies, and developing children," said Wu, "reinforcing the fact that this chemical has no place in our drinking water. Today's action should be the first in a series of necessary steps to fix this problem and clean up our water."
"We definitely think the science is there to get atrazine off the market, and there aren't really economic benefits that outweigh that consideration," said Wu, who points to studies that show not using atrazine may have, at most, a one percent impact on crop yields.
The NRDC report showed that atrazine was found in all of the watersheds monitored by EPA and 90 percent of the drinking water sampled in the monitored areas.
USGS scientists conducted a study of atrazine and other herbicides in Midwestern agricultural fields (Photo courtesy USGS Toxic Substances Hydrology Program)
Contamination was most severe in Illinois, Iowa, Indiana, Missouri, and Nebraska. A previous study by the U.S. Geological Survey found that 75 percent of stream water and about 40 percent of all groundwater samples from agricultural areas contained atrazine.
The NRDC report suggests that the EPA has been ignoring atrazine contamination, that the monitoring of the herbicide is misleading and its regulation insufficient.
The monitoring programs were not designed to find the biggest problems, the screening levels are too permissive, and the monitoring ignores more than 1,000 vulnerable watersheds.
One of the chief findings of the NRDC report was that the way atrazine is now regulated allows levels in drinking water to peak at high concentrations but still fall within an allowable "average."
Atrazine has been denied regulatory approval by the European Union and is banned in Europe, even in Switzerland, the home of primary manufacturer, Sygenta.
Syngenta defends the safety of its product, saying, "As a popular herbicide in more than 60 countries around the world, atrazine has been carefully studied for years. In 2008, none of the 122 community water systems monitored in 10 states where atrazine is used most exceeded the federal standards set for atrazine in drinking water or raw water."
"Atrazine can be occasionally detected in water at extraordinarily low concentrations (parts per billion), but these low levels pose no threat to human health. A person could drink thousands of gallons of water containing 3 parts per billion atrazine every day for a lifetime, and still not be affected by atrazine," said Tim Pastoor, Ph.D., principal scientist for Syngenta.
But the nonprofit Center for Biological Diversity complains, "Although required by court order in 2003 to further assess atrazine, the EPA entered into a private deal whereby the atrazine manufacturer Syngenta was allowed to conduct contaminant monitoring, assessing just three percent of the watersheds identified as "at risk" of atrazine contamination."
A new class action lawsuit representing water districts throughout Illinois cites recent research showing that atrazine in drinking water is unsafe at any level, even at concentrations below EPA guidelines.
Attorney Stephen Tillery, who represents the class action plaintiffs, said "The U.S. EPA conducted more than 40 private meetings with the leading manufacturer of atrazine to devise a testing protocol that manipulatively distorts atrazine levels in water."
Tillery filed the class action suit in August in the Third Judicial Circuit Court in Madison County on behalf of a rural sanitary district near Edwardsville and other water districts throughout the state. The suit was filed against atrazine manufacturer Syngenta Crop Protection Inc. with headquarters in Switzerland and Growmark Inc. with principal offices in Bloomington doing business under the "FS" name.
"It's time to ban atrazine to protect our drinking water and our most imperiled wildlife," said Jeff Miller, a conservation advocate with the Center for Biological Diversity. "There is no reason to continue use of this poisonous contaminant given the building evidence of harm to humans and endangered species."
NRDC recommends that consumers concerned about atrazine in their water use a household water filter, such as one that fits on the tap. Consumers should make sure that the filter they choose is certified by NSF International to meet American National Standards Institute (ANSI) Standard 53 for the reduction of volatile organic compounds.
Copyright Environment News Service (ENS) 2009. All rights reserved.
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