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endless studies to keep atrazine polluting
The article below deals with the maneuvering over atrazine "to ban or
not to ban, that is the question". Efforts are being made to carry on
endless studies to keep atrazine polluting the planet. Atrazine tolerant
canola , claimed to have been selected from volunteers (TT canola ) is
being grown in Australia in spite of its yield deficiency. TT soy and
other crops may push the globe to the edge of ecological doom.
Nature 420, 256 (2002); doi:10.1038/420256a
Doubts linger over America's top herbicide REX DALTON
[SALT LAKE CITY] Rising concerns about the environmental impact of the
most widely used herbicide in the United States have led researchers to
call for more time to study its effects before approval for the agent's
use is renewed.
Researchers have until next February to submit their findings on the
herbicide atrazine to the Environmental Protection Agency (EPA). The
agency plans to complete its review of the chemical during 2003.
But at the annual meeting of the Society of Environmental Toxicology and
Chemistry (SETAC) in Salt Lake City, Utah, this week, some scientists
said that the necessary studies cannot be finished in time for the EPA's
Researchers in the field want to conduct a detailed study of what
concentrations of atrazine cause environmental damage by disrupting the
sexual development of amphibians, says Timothy Gross, an ecotoxicologist
with the US Geological Survey in Gainesville, Florida.
Tyrone Hayes suggests that reasonably low levels of atrazine can
adversely affect frogs' development.
Earlier this year, two studies indicated that atrazine at levels as low
as 0.1 parts per billion (p.p.b.) in water disrupted the sexual
development of male frogs (T. Hayes et al. Proc. Natl. Acad. Sci. USA
99, 5476–5480; 2002 and T. Hayes et al. Nature 419, 895–896; 2002).
But other scientists, including Gross, dispute this, and have released
unpublished results showing that much higher water concentrations of
about 25 p.p.b. are needed to affect the frogs' sexual development.
Government studies show that atrazine can be found at levels as high as
50 p.p.b. in US waters, and at even higher concentrations of several
parts per million in agricultural run-off.
"The water is very muddy right now," says Gross, who also serves on a
panel studying atrazine for Syngenta, the herbicide's Swiss-based
manufacturer. Syngenta wants the EPA to re-register atrazine for use in
the United States. It has been banned in some European countries.
Gross' comments came after a spirited session at the SETAC meeting where
academic and industry-backed scientists presented their findings on the
impact of atrazine on wild and laboratory amphibians.
Tyrone Hayes — an evolutionary endocrinologist at the University of
California, Berkeley, who is the lead author of the studies in Nature
and the Proceedings of the National Academy of Sciences — was added at
the last minute to the SETAC session, which already included prominent
university scientists, such as James Carr of Texas Tech University in
Lubbock, whose studies of atrazine are funded by Syngenta.
Once February's deadline is reached, the EPA will set up a scientific
advisory panel to advise it on re-registering atrazine. A decision is
expected next October.
But both Hayes and Gross say that a new study is needed to settle the
debate, and that the February deadline won't allow this to happen. "We
need a tie-breaker study," says Gross.
Thomas Steeger, an EPA biologist working on atrazine re-registration,
says that the agency may be reluctant to extend the study deadline. But
he adds that he wouldn't be surprised if the scientific advisory panel
called for more study before issuing a recommendation on how the
herbicide should be regulated.