[Pharmwaste] High Weedkiller (atrazine) Levels Found in River Checks
dldebiasi at deq.virginia.gov
Wed Dec 12 09:18:19 EST 2007
Atrazine has been banned by the Europeon Union since 2005 - EPA is still
High Weedkiller Levels Found in River Checks
By Juliet Eilperin
Washington Post Staff Writer
Sunday, December 9, 2007; A06
Atrazine, the second most widely used weedkiller in the country, is
showing up in some streams and rivers at levels high enough to
potentially harm amphibians, fish and aquatic ecosystems, according to
the findings of an extensive Environmental Protection Agency database
that has not been made public.
The analysis -- conducted by the chemical's manufacturer, Syngenta Crop
Protection -- suggests that atrazine has entered streams and rivers in
the Midwest at a rate that could harm those ecosystems, several
scientific experts said. In two Missouri watersheds, the level of
atrazine spiked to reach a "level of concern" in both 2004 and 2005,
according to the EPA, and an Indiana watershed exceeded the threshold in
Much of the data on atrazine levels has remained private because
Syngenta's survey of 40 U.S. watersheds was done in connection with the
EPA's 2006 decision to renew its approval of the pesticide. The
Washington Post obtained the documents from the Natural Resources News
Service, a District-based nonprofit group focused on environmental
Atrazine has been linked to sexual abnormalities in frogs and fish in
several scientific studies, but the EPA ruled in September that the
evidence was not sufficiently compelling to restrict use of the
pesticide. EPA spokeswoman Jennifer Wood said the agency "has concluded
that atrazine does not adversely affect gonadal development in frogs,
based on a thorough review of 19 laboratory and field studies, including
studies submitted by [Syngenta] and others in the public literature."
The pesticide is popular among corn and sorghum farmers despite the
controversy because it is inexpensive and blocks photosynthesis, thus
killing plants to which it is applied.
"It works and it's inexpensive, and that's what farmers love," said Tim
Pastoor, head of toxicology at Syngenta. "It's magic for them. It's like
the aspirin of crop protection."
EPA officials and independent experts spent last week in meetings in
Arlington, debating the "ecological significance" of atrazine water
contamination, according to agency documents. The results of the
deliberations -- the monitoring data was plugged into computer models to
estimate the effects on ecosystems -- will be published in several weeks
and will help determine how EPA officials regulate the pesticide in the
The federal government first approved atrazine in the 1950s, but it came
under increased scrutiny in the late 1990s after Tyrone B. Hayes, a
professor of integrative biology at the University of California at
Berkeley, did a series of studies -- first for chemical companies and
then on his own -- that indicated that tiny amounts of the pesticide
de-masculinized tadpoles of African clawed frogs. The European Union
declared it a harmful "endocrine disrupter" and banned it as of 2005,
but the EPA decided to allow its continued use after determining that
the agency lacked a standard test for measuring the hormone-disrupting
effects of chemicals.
Instead, EPA officials and company representatives agreed on a plan to
monitor atrazine levels in "40 of the most vulnerable watersheds in the
country," said Jim Jones, deputy assistant administrator for the EPA's
Office of Prevention, Pesticides, and Toxic Substances.
Syngenta has collected more than 10,000 samples since 2004, Pastoor
said, taking readings at least every four days at each site.
Jones said there are limits on what details of the Syngenta survey can
be released to the public -- the company claims some of the data is
proprietary information, and anyone who requests the information must
pledge not to share it with competing pesticide companies -- but the
monitoring system is protecting the public's health.
Nancy Golden, a biologist and toxicologist at the U.S. Fish and Wildlife
Service who studies how chemicals affect aquatic creatures, said fish
exposed to as little as 0.5 parts per billion of atrazine in the lab
demonstrate behavioral problems. At higher levels, they experience
stunted growth. The levels of atrazine in 2004 in the two Missouri sites
were more than 100 times the 0.5 parts per billion concentration, the
Syngenta data show.
Golden said the data documented "atrazine levels that are sustained at
pretty high levels for several weeks. That's definitely a cause for
Peter L. deFur, a biologist at Virginia Commonwealth University, said
"chronic low-level exposure" to atrazine can harm aquatic life. "I don't
think low levels of atrazine exposures are safe," deFur said.
Charles Scott, field supervisor for the Fish and Wildlife Service's
Missouri Ecological Services Field Office, said high levels of atrazine
in northeastern Missouri could potentially affect several endangered and
threatened species, including the pallid sturgeon, the Higgins' eye
mussel, the fat pocketbook mussel and the decurrent false aster, a
wetland plant. "It has a lot of biological impacts," Scott said of the
The EPA has asked Syngenta to do additional monitoring at the two sites
in northeastern Missouri where atrazine concentrations significantly
exceeded 10 parts per billion, the level at which the agency believes it
can impact aquatic systems. In these two watersheds, concentrations
reached more than 50 parts per billion for days at a time.
Wood, the EPA spokeswoman, said the Indiana watershed did not trigger
the agency's level of concern in 2006 and the company will be monitoring
it for another year.
Pastoor, who noted that atrazine's effect of stunting plant growth is
reversed as soon as the pesticide is taken away, said the fact that two
watersheds showed high levels of exposure "doesn't mean there's a
problem there. It just means there's a yellow flag that says you should
take a look."
The two sites in question, he added, were prone to excessive runoff
because they have an impervious clay soil that channels runoff into
waterways, the land is sloped, and one of the farmers working the land
had cleared much of the vegetation. Syngenta sales agents and local corn
growers are trying to reform the practices of the farmer in question.
"We anticipate that site will significantly improve," Pastoor said,
adding that the computer models Syngenta ran suggest there has been no
ecological damage to the watersheds the company has monitored.
Hayes, who stopped working as a contractor for a coalition of chemical
companies years ago and is now one of atrazine's most vocal opponents,
said he does not think the federal government is surveying the pesticide
enough in light of its pervasive influence.
"What's most disturbing about the information you're talking about is
all that EPA requires Syngenta to do is monitor atrazine in a few key
sites," Hayes said. "Industry's been allowed to have such a huge hand in
the regulation of atrazine."
Deborah L. DeBiasi
Email: dldebiasi at deq.virginia.gov
WEB site address: www.deq.virginia.gov
Virginia Department of Environmental Quality
Office of Water Permit Programs
Industrial Pretreatment/Toxics Management Program
PPCPs, EDCs, and Microconstituents
Mail: P.O. Box 1105, Richmond, VA 23218 (NEW!)
Location: 629 E. Main Street, Richmond, VA 23219
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