Scientists Warn of Danger with Genetically Engineered Corn

Environmental researchers at Indiana University are warning of a danger that comes from genetically engineered corn crops. Their research shows that one of the most widely planted varieties can potentially harm the aquatic ecosystems.

They have discovered that the pollen and parts of the plants of the Bt variety of genetically engineered corn are being washed into the streams near the fields and the pollen and parts are toxic.

Their lab trials also showed that eating Bt corn byproducts increased the death rates and reduced the growth of caddisflies, which are aquatic insects that happen to be related to the destructive insects that the toxin in Bt corn is supposed to kill. The caddisflies are not harmful and in fact are food for fish and amphibians. Killing them off with the toxins is interfering with the whole ecosystem.

Bt corn has been genetically engineered to have a gene that normally exists in a micro-organism called Bacillus thuringiensis. This gene produces a toxin that will protect the corn from harmful insects and one that it is targeted to kill is the European corn borer. This variety of corn has been in use since 1996. Figures show that in 2006, 35% of the entire corn crop in the county is a genetically modified variety.

Genetically engineered crops have to be licensed by the U.S. Environmental Protection Agency to see if they will have any adverse effects, but when Bt was tested, they tested it on a crustacean called Daphnia. This creature is one that is commonly used in tests, but they are in no way related to the insects that the toxins are designed to kill and therefor the tests gave no indication of the actual impact the toxins would have.

This is not the first time that there has been controversy about the Bt corn. Back in 1999, there was a report that showed it might be harmful to monarch butterflies. The federal government's Agriculture Research Service conducted studies and determined that there was no significant threat to the monarchs, but it was this study that prompted this team to explore if there was any other impact from Bt corn affecting the streams.

The research took more than 2 years to complete. The actual research itself was done in 2005 and 2006 and then they needed to compile and report on the findings. They conducted the research in one of the heavily famed sections in northern Indiana. They measured the input of Bt corm pollen and parts of the plant like leaves and cobs in a total of 12 headwater streams. They collected the material for the tests using litter traps. The also found pollen from the corn inside certain caddisflies, which meant they were feeding on the pollen

When they conducted the lab tests, they fed some of the caddisflies leaves from the corn and another group were fed non Bt corn litter. The results showed that the group fed the leaves from. By corn had growth rates less than half of those who were fed the other diet.

They also found that a different type of caddisfly had a higher death rate when they were exposed to Bt corn pollen at levels that were between 2 and 3 times the level found in the test sites.

They found very different levels of the corn pollen and the byproducts at different locations. They also say there is likely that there will be differences in different areas. Farmers in Iowa and Illinois are planting more of the Bt corn than farmers in Indiana, therefor, even though the levels that killed the caddisflies in Indiana, might be normal levels in Iowa and Illinois and might be the actual conditions in the streams in those states.

The lead researcher is Todd V. Royer, an assistant professor in the IU School of Public and Environmental Affairs, and the rest of the team is 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.

Source: Indiana University http://www.newswise.com/p/