Toxic Herbicide, Atrazine,
Solution for GE Superweeds?

"Prompt action to limit further pollution from atrazine may be delayed by
the development of "super weeds" from current herbicide tolerant GM crops,
and volunteer crops or weeds that develop multiple-herbicide tolerance by
gene flow between commercial varieties. Some authorities and government
regulators advise that herbicides such as atrazine should be used to control
superweeds. This is the height of lunacy and irresponsibility. There should
be a global ban on atrazine."

The Institute of Science in Society
Science Society Sustainability
http://www.i-sis.org.uk

General Enquiries sam@i-sis.org.uk
Website/Mailing List press-release@i-sis.org.uk
ISIS Director m.w.ho@i-sis.org.uk
===================================================

Atrazine Poisoning Worse Than Suspected
*********************************
Controversy erupted over new findings that atrazine may be linked to global
demise of frogs. Prof. Joe Cummins and Dr. Mae-Wan Ho review the evidence on
the endocrine-disrupting and carcinogenic effects of atrazine, especially in
the light of the non-linearity of biological activities, and call for a
global ban of the herbicide.

If you wish to see the complete document
[http://www.i-sis.org.uk/full/atrazineFull.php]
with references, please consider becoming a member
or friend of ISIS. Full details here
[http://www.i-sis.org.uk/membership.php ]

Atrazine is an herbicide registered in the United States for the control of
broadleaf weeds and some grassy weeds. It is currently used on corn,
sorghum, sugarcane, wheat (to get rid of wheat stubble on fallow land
following wheat harvests; wheat is not the target crop), guava, macadamia
nuts, orchard grass and hay, range grasses, and southern turf grasses.
Atrazine is most widely used on corn followed by sorghum and sugarcane.
Atrazine is registered for use on range grasses for establishing permanent
grass cover on rangelands and pastures under the Conservation Reserve
Program (CRP) in four states: Oklahoma, Nebraska, Texas, and Oregon.
The CRP is administered by the US Department of Agriculture (USDA).

There are prohibitions against grazing on these CRP lands, and cutting the
grasses for hay, except in national emergencies, such as severe drought, and
there are "right-of-way" uses with grazing restrictions. Atrazine is also
registered for use on the following non-agricultural sites: lawns, golf
courses, and sod farms. Worlwide, atrazine is a leading agricultural
chemical, and so extensively used that it has been identified as a
significant pollutant in surface water, groundwater, in offshore areas and
in the atmosphere.

Atrazine acts by inhibiting photosynthesis. Many atrazine-tolerant mutations
have begun to appear in weeds, and this tolerance is predominantly based on
detoxifying atrazine by binding it to glutathione, a mechanism in naturally
atrazine-tolerant corn. Efforts have been made to select or produce
atrazine-tolerant mutants crops such as soybean that is otherwise difficult
to rotate with atrazine-treated corn or potato.

Most of the crop-plant mutants had impaired productivity, but in potato, an
atrazine-binding photosynthetic protein is mutated, and this makes it
tolerant to the herbicide without impaired productivity. Transgenic potato
containing a complex of human cytochrome p450 genes was found to be tolerant
to atrazine, and was proposed for phytoremediation of chemically polluted
croplands. Unfortunately, the cytochrome p450 enzymes are very important in
metabolism of man-made chemicals, they both inactivate many carcinogens, and
in some instances, activate pollutants to form carcinogens. Atrazine is used
worldwide, but its continued application is hampered by appearance of
atrazine-tolerant weeds.

Atrazine was in the news recently in connection with the global demise of
frogs. Frogs were reported to be demasculinized or became hermaphrodite
after being exposed at low ecologically relevant doses of the herbicide in
the laboratory. Levels as low as 0.1 parts per billion atrazine induced
hermaphroditism. This was confirmed by fuller ecological evidence that
atrazine is associated with hermaphroditism in frogs at levels an order of
magnitude below the currently accepted standard.

Those findings were criticized on several grounds, but mainly on the basis
that very low levels of atrazine produced a stronger impact than levels 250
times higher, and that the low levels of atrazine did not induce the
cytochrome p450 enzyme aromatase. Such criticism is significant, but should
be considered in the light that endocrine disrupting chemicals often have
more marked effect at lower doses, and the enzyme aromatase, though
important in producing the feminizing hormone estrogen, shows complex
cellular patterns of activation in animals exposed to feminizing pollutants..

The endocrine-disrupting effects of atrazine are not restricted to frogs.
Atrazine reduced olfactory-mediated endocrine functions in salmon at levels
commonly observed in polluted water. And it was found to inhibit
testosterone production in prepubertal rats.

The impact of atrazine on endocrine disruption is very serious. A study of
aquatic ecosystems concluded that a single universal maximum on atrazine in
catchments does not provide adequate environmental protection, and suggests
flexible limits be set. However, it may be far more reasonable to discuss
eliminating further atrazine input into the aquatic environment altogether.

Another important factor that is almost never considered in environmental
risk assessment is that biological activities are predominantly nonlinear:
weak forces or extremely low concentrations of a chemical may have
disproportionately large effects at times, and conversely, strong forces or
high concentrations of the chemical may have no effects at all.

The debate over the biological effects of trace chemical pollutants, which
Rachel Carson began some fifty years ago, is getting to resemble the debate
over the biological effects of weak electromagnetic fields that erupted in
the 1970s, and more recently the effects of microwaves emanating from mobile
phones and antennas. It is symptomatic of the basic inadequacy of the
linear, mechanistic model of living systems that still dominates the
scientific establishment, at a time when scientists across the disciplines
are already working with non-linear dynamical models and even quantum
coherent models of living systems.

It has not escaped our notice that in homeopathy, more dilute concentrations
of substances are said to be 'potentised', and expected to produce stronger
effects, or in any case, effects opposite to what the same substance would
produce at high concentrations. That, too, could fall within the spectrum of
nonlinear behaviour of living systems, although it is much more difficult to
explain.

Andrew Marino and his coworkers in LSU Health Science Center, Shreveport,
Louisiana, have recently devised nonlinear statistical methods for analyzing
the biological effects of weak electromagnetic fields that may be relevant
to a range of data including the endocrine-disrupting effects of atrazine
and other environmental pollutants.

The International Agency for Research on Cancer determined that there is
sufficient evidence for the carcinogenicity of atrazine in animals, but not
in humans. The United States Environmental Protection Agency (EPA) concluded
that the cancer studies showing atrazine carcinogenic in animals were not
applicable to human but EPA did make minor adjustments to the regulatory
framework for atrazine based on the elevated pollution by that herbicide.
Recently, atrazine was found to potentiate arsenic toxicity in human cells,
a result that causes concern in areas where drinking water is polluted with
both toxins. Even though cancer has been a focus of regulatory action on the
herbicide, impacts such as the intra-uterine growth retardation observed in
communities with atrazine-polluted drinking water supplies have been given
scant consideration.

Atrazine can be present in parts per million in agricultural run-offs and
can reach 40 parts per billion in precipitation. The global impact of
atrazine is staggering. Significant atrazine pollution has been found in the
Lio-He and Yangtse rivers of China, and a review of the atmospheric
dispersion of atrazine shows impacts of the herbicide even in isolated areas
of the globe.

Prompt action to limit further pollution from atrazine may be delayed by the
development of "super weeds" from current herbicide tolerant GM crops, and
volunteer crops or weeds that develop multiple-herbicide tolerance by gene
flow between commercial varieties. Some authorities and government
regulators advise that herbicides such as atrazine should be used to control
superweeds. This is the height of lunacy and irresponsibility. There should
be a global ban on atrazine.

If you wish to see the complete document [
http://www.i-sis.org.uk/full/atrazineFull.php ] with references, please
consider becoming a member or friend of ISIS. Full details here [
http://www.i-sis.org.uk/membership.php ]

Home | News | Organics | GE Food | Health | Environment | Food Safety | Fair Trade | Peace | Farm Issues | Politics
Español | Campaigns | Buying Guide | Press | Search | Donate | About Us | Contact Us

Organic Consumers Association - 6771 South Silver Hill Drive, Finland MN 55603
E-mail: Staff · Activist or Media Inquiries: 218-226-4164 · Fax: 218-353-7652
Please support our work. Send a tax-deductible donation to the OCA

Fair Use Notice: The material on this site is provided for educational and informational purposes. It may contain copyrighted material the use of which has not always been specifically authorized by the copyright owner. It is being made available in an effort to advance the understanding of scientific, environmental, economic, social justice and human rights issues etc. It is believed that this constitutes a 'fair use' of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material on this site is distributed without profit to those who have an interest in using the included information for research and educational purposes. If you wish to use copyrighted material from this site for purposes of your own that go beyond 'fair use', you must obtain permission from the copyright owner. The information on this site does not constitute legal or technical advice.