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.
===============================================================================
GM
WATCH daily list
http://www.gmwatch.org
---
---
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.
----------------------------------------------------------
You
are subscribed as
[log in to unmask]To unsubscribe simply click the link
below:
http://www.gmwatch.org/unsub.asp?ID=1097&sec=pbmhh
This
message has been sent because you subscribed to the GM Watch
List.
http://www.gmwatch.org
------------------------------------------------------------
-
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
To unsubscribe
from the IOWA-TOPICS list, send any message
to:
[log in to unmask]Check out our
Listserv Lists support site for more
information:
http://www.sierraclub.org/lists/faq.asp