I found this article fascinating.
Now I'm wondering what you've experienced with GMOs in your life...
A northern Indiana stream.
New Study Shows Genetically Engineered Corn Could Pollute Aquatic
BLOOMINGTON, Ind. -- A study by an Indiana University environmental
science professor and several colleagues suggests a widely planted
variety of genetically engineered corn has the potential to harm aquatic
ecosystems. The study is being published this week by the journal
Proceedings of the National Academies of Sciences.
Researchers, including Todd V. Royer, an assistant professor in the IU
School of Public and Environmental Affairs, established that pollen and
other plant parts containing toxins from genetically engineered Bt corn
are washing into streams near cornfields.
They also conducted laboratory trials that found consumption of Bt corn
byproducts produced increased mortality and reduced growth in
caddisflies, aquatic insects that are 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. Water resources are
something we depend on greatly."
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. It was funded by the National Science Foundation.
Bt corn is engineered to include a gene from the micro-organism Bacillus
thuringiensis, which produces a toxin that protects the crop from pests,
in particular the European corn borer. It was licensed for use in 1996
and quickly gained popularity. In 2006, around 35 percent of corn
acreage planted in the U.S. 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 commonly used for toxicity tests, and not insects that are
more closely related to the target pests, Royer said.
Royer emphasized that, if there are unintended consequences of planting
genetically engineered crops, farmers shouldn't be held responsible. In
a competitive agricultural economy, producers have to use the best
technologies they can get.
"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."
There was a public flap over the growing use of Bt corn in 1999, when a
report indicated it might harm monarch butterflies. But studies
coordinated by the government's Agriculture Research Service and
published in PNAS concluded there 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 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 and corn
byproducts (e.g., leaves and cobs) in 12 headwater streams, using litter
traps to collect the materials. They also found corn pollen in the guts
of certain 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 likely also to be
significant geographical variation; farmers in Iowa and Illinois, for
example, 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
Once published, the paper will be available at
www.pnas.org/cgi/content/abstract/0707177104v1. Reporters can obtain a
copy of this article prior to its publication by contacting the PNAS
News Office at 202-334-1310 or PNASnews@nas.edu
. Reporters registered
with PNAS's EurekaAlert can obtain the article through that service.