Forwarded by Jane Clark
National Science Foundation
Genetically Engineered Corn May Harm Stream Ecosystems - US National Science
Foundation
(NSF)http://www.nsf.gov/news/news_summ.jsp?cntn_id=110265&org=NSF&from=news
Ecological impacts of genetically engineered corn are particularly important
because of increased corn demand created by biofuels production
Genetically modified corn detritus and pollen affect non-target organisms
downstream.
October 9, 2007
A new study indicates that a popular type of genetically engineered
corn--called Bt corn--may damage the ecology of streams draining Bt corn
fields in ways that have not been previously considered by regulators. The
study, which was funded by the National Science Foundation, appears in the
Oct. 8 edition of The Proceedings of the National Academy of Sciences.
This study provides the first evidence that toxins from Bt corn may travel
long distances in streams and may harm stream insects that serve as food for
fish. These results compound concerns about the ecological impacts of Bt
corn raised by previous studies showing that corn-grown toxins harm
beneficial insects living in the soil.
Licensed for use in 1996, Bt corn is engineered to produce a toxin that
protects against pests, particularly the European corn borer. Bt corn now
accounts for approximately 35 percent of corn acreage in the U.S., and its
use is increasing.
"As part of the licensing process for genetically modified crops, the U.S.
Environmental Protection Agency (EPA) was responsible for testing and
identifying potential environmental consequences from the planting of Bt
corn," says Jennifer Tank, who is from the University of Notre Dame and is a
member of the team studying Bt corn.
To fulfill this requirement, EPA completed studies that assumed that plant
parts would remain in fields without being carried away by streams draining
agricultural lands, says Tank. In addition, EPA only tested the impacts of
Bt corn on smalllakeorganisms that are typically used to test the impacts of
chemicals on aquatic ecosystems.
The agency did not evaluate the impacts of Bt corn on organisms that live
instreams--even though Midwest agricultural lands where Bt corn is grown are
heavily intersected by streams draining the landscape. But despite the
limitations of its tests, EPA concluded that Bt corn "is not likely to have
any measurable effects on aquatic invertebrates."
To more comprehensively evaluate the ecological impacts of Bt corn than did
the EPA, the research team did the following:
1. Measured the entry of Bt plant parts--including pollen, leaves and
cobs--in 12 streams in a heavily farmed Indiana region. The research team's
results demonstrate that these plant parts are washing into local steams.
Moreover, during storms, these plant parts are carried long distances and
therefore could have ecological impacts on downstream water bodies, such as
lakes and large rivers.
2. Collected field data indicating that Bt corn pollen is being eaten by
caddisflies, which are close genetic relatives of the targeted Bt pests.
Todd V. Royer, a member of the research team from Indiana University, says
that caddisflies "provide a food resource for higher organisms like fish and
amphibians."
3. Conducted laboratory tests showing that consumption of Bt corn byproducts
increased the mortality and reduced the growth of caddisflies. Together with
field data indicating that the caddisflies are eating Bt corn pollen, these
results "suggest that the toxin in Bt corn pollen and detritus can affect
species of insects other than the targeted pest," Tank said.
Royer says that "if our goal is to have healthy, functioning ecosystems, we
need to protect all the parts. Water resources are something we depend on
greatly."
"Overall, our study points to the potential for unintended and unexpected
consequences from the widespread planting of genetically engineered crops,"
Tank said. "The exact extent to which aquatic ecosystems are, or will be,
impacted is still unknown and likely will depend on a variety of factors,
such as current ecological conditions, agricultural practices and
climate/weather patterns."
James Raich, a National Science Foundation program director, adds that
"increased use of corn for ethanol is leading to increased demand for corn
and increased acreage in corn production. Previous concerns about the
nutrient enrichment of streams that accompany mechanized row-crop
agriculture are now compounded by toxic corn byproducts that enter our
streams and fisheries, and do additional harm."
The Bt corn researchers stress that their study should not be viewed as an
indictment of farmers."We do not imply that farmers are somehow to blame for
planting Bt corn, nor are they responsible for any unintended ecological
consequences from Bt corn byproducts," Tank said. "Farmers are, to a large
extent, required to use the latest technological advances in order to stay
competitive and profitable in the current agro-industrial system."
Media Contacts
Cheryl Dybas, National Science Foundation (703) [log in to unmask]
William Gilroy, University of Notre Dame (574) [log in to unmask]
Program Contacts
James Raich, National Science Foundation (703) [log in to unmask]
Co-Investigators
Todd V. Royer, Indiana University (812) 855-097 [log in to unmask]
Jennifer Tank, University of Notre Dame (574) 631-3976 [log in to unmask]
Matt Whiles, Southern Illionois University
(618)453-7639 [log in to unmask]
Emma J. Rosi-Marshall, Loyola University-Chicago (773)508-8859
[log in to unmask]
The National Science Foundation (NSF) is an independent federal agency that
supports fundamental research and education across all fields of science and
engineering, with an annual budget of $5.92 billion. NSF funds reach all 50
states through grants to over 1,700 universities and institutions. Each
year, NSF receives about 42,000 competitive requests for funding, and makes
over 10,000 new funding awards. The NSF also awards over $400 million in
professional and service contracts yearly.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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
|
