This message is very important, especially given the Iowa Chapter's focus on
water issues.
Here it is again, without the extraneous text at the top.
Tom
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Transgenic Corn Found to Damage Stream Ecosystems
Environmental News Service, October 11 2007
http://www.ens-newswire.com/ens/oct2007/2007-10-11-096.asp
BLOOMINGTON, Indiana, October 11, 2007 (ENS) - A widely planted variety of
genetically engineered corn has the potential to harm aquatic ecosystems,
finds a new study by an Indiana University professor of environmental science and
his colleagues.
Pollen and other plant parts containing toxins from genetically engineered
Bt corn are washing into streams near cornfields and harming a type of fly
that is eaten by fish and amphibians, the study demonstrates.
Bt corn is engineered to include a gene from the micro-organism Bacillus
thuringiensis, Bt, which produces a toxin that protects the crop from pests,
especially the European corn borer.
The research team led by Todd Royer, an assistant professor in the Indiana
University School of Public and Environmental Affairs, found that consumption
of Bt corn pollen, leaves and cobs increased mortality and reduced growth in
caddisflies, aquatic insects related to the pests targeted by the toxin in Bt
corn.
"Caddisflies," Royer said, "are a food resource for higher organisms like
fish and amphibians. And, if our goal is to have healthy, functioning
ecosystems, we need to protect all the parts."
Caddisfly larvae are an important part of stream ecosystems, where they help
control algae populations and provide food for fish and other creatures. In
healthy streams, caddisflies are very common and their cases are found by
the hundreds under rocks and logs.
Bt corn was licensed for use in 1996 and quickly gained popularity. By 2006,
around 35 percent of corn acreage planted in the United States was
genetically modified, the study says, citing U.S. Department of Agriculture data.
Before licensing Bt corn, the U.S. Environmental Protection Agency conducted
trials to test its impact on water biota. But it used Daphnia, a crustacean
often used for toxicity tests, and not insects that are more closely related
to the target pests, Royer said.
"Every new technology comes with some benefits and some risks," he said. "I
think probably the risks associated with widespread planting of Bt corn were
not fully assessed."
If there are unintended consequences of planting genetically engineered
crops, Royer says farmers should not be held responsible. In a competitive
agricultural economy, producers have to use the best technologies they can get, he
said.
Funded by the National Science Foundation, the study is published this week
by the journal "Proceedings of the National Academies of Science, PNAS."
There was a public outcry over the use of Bt corn in 1999, when a report
indicated it might harm monarch butterflies. But studies coordinated by the
federal Agricultural Research Service and published in PNAS concluded Bt corn was
not a significant threat to monarchs.
Around that time, Royer said, he and his colleagues wondered whether the
toxin from Bt corn was getting into streams near cornfields, and, if so, whether
it could have an harmful impact on aquatic insects.
Their research, conducted in 2005 and 2006 in an intensely farmed region of
northern Indiana, measured inputs of Bt corn pollen, leaves and cobs in 12
headwater streams, using litter traps to collect the materials. They also found
corn pollen in the guts of caddisflies, showing they were feeding on corn
pollen.
In laboratory trials, the researchers found caddisflies that were fed leaves
from Bt corn had growth rates that were less than half those of caddisflies
fed non-Bt corn litter. They also found that a different type of caddisfly
had significantly increased mortality rates when exposed to Bt corn pollen at
concentrations between two and three times the maximum found in the test
sites.
Royer said there was considerable variation in the amount of corn pollen and
byproducts found at study locations and there is geographical variation.
Farmers in Iowa and Illinois, for instance, are planting more Bt corn than those
in Indiana. The level of Bt corn pollen associated with increased mortality
in caddisflies, he said, "could potentially represent conditions in streams
of the western Corn Belt."
There are four bands of Bt corn seed available commercially - YieldGard from
Northrup King (Novartis); YieldGard2 from Monsanto; YieldGard Rootworm from
Monsanto; and Herculex from Pioneer DowAgra-Sciences.
Other crops such as potatoes and cotton also make use of Bt technology. By
1999, 29 million acres of Bt corn, potato and cotton were grown globally.
When proponents of Bt technology list the benefits, they often say the Bt
proteins in the crops will not kill beneficial insects. Royer and his team
showed that claim is not accurate in the case of caddisflies.
Other principal investigators for the study, titled "Toxins in transgenic
crop byproducts may affect headwater stream ecosystems," were Emma
Rosi-Marshall of Loyola University Chicago, Jennifer Tank of the University of Notre
Dame, and Matt Whiles of Southern Illinois University.
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