1.GM maize 'has polluted rivers across the United States'
2.Insecticides from genetically modified corn present in adjacent streams
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1.GM maize 'has polluted rivers across the United States'
Steve Connor, Science Editor
The Independent, 28 September 2010
http://www.independent.co.uk/environment/nature/gm-maize-has-polluted-rivers-across-the-united-states-2091300.html
An insecticide used in genetically modified (GM) crops grown extensively in the United States and other parts of the world has leached into the water of the surrounding environment.
The insecticide is the product of a bacterial gene inserted into GM maize and other cereal crops to protect them against insects such as the European corn borer beetle. Scientists have detected the insecticide in a significant number of streams draining the great corn belt of the American mid-West.
The researchers detected the bacterial protein in the plant detritus that was washed off the corn fields into streams up to 500 metres away. They are not yet able to determine how significant this is in terms of the risk to either human health or the wider environment.
"Our research adds to the growing body of evidence that corn crop byproducts can be dispersed throughout a stream network, and that the compounds associated with genetically modified crops, such as insecticidal proteins, can enter nearby water bodies," said Emma Rosi-Marshall of the Cary Institute of Ecosystem Studies in Millbrook, New York.
GM crops are widely cultivated except in Britain and other parts of Europe. In 2009, more than 85 per cent of American corn crops were genetically modified to either repel pests or to be tolerant to herbicides used to kill weeds in a cultivated field.
The GM maize, or corn as it is called in the US, has a gene from the bacterium Bacillus thuriengensis (Bt) inserted into it to repel the corn borer beetle. The Bt gene produces a protein called Cry(12A)b which has insectidical properties.
The study, published in the journal Proceedings of the National Academy of Science, analysed 217 streams in Indiana. The scientists found 86 per cent of the sites contained corn leaves, husks, stalks or cereal cobs in their channels and 13 per cent contained detectable levels of the insectidical Cry(12A)b proteins.
"The tight linkage between corn fields and streams warrants further research into how corn byproducts, including Cr(12A)b insecticidal proteins, potentially impact non-target ecosystems, such as streams and wetlands," Dr Rosi-Marshall said.
All of the stream sites with detectable insecticidal proteins were located within 500 metres of a corn field. The ramifications are vast just in Iowa, Illinois, and Indiana, where about 90 per cent of the streams and rivers some 159,000 miles of waterways are also located within 500 metres of corn fields.
After corn crops are harvested, a common agricultural practice is to leave discarded plant material on the fields. This "no-till" form of agriculture minimises soil erosion, but it then also sets the stage for corn byproducts to enter nearby stream channels.
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2.Insecticides from genetically modified corn present in adjacent streams
Stream ecosystems are tightly linked to agricultural fields and should be considered when adopting new agricultural technologies
Public release date: 27-Sep-2010
http://www.eurekalert.org/pub_releases/2010-09/cioe-ifg092410.php
Contact: Lori M. Quillen
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845-677-7600 x233
Cary Institute of Ecosystem Studies
In a paper published this week in the Proceedings of the National Academy of Sciences, Cary Institute aquatic ecologist Dr. Emma Rosi-Marshall and colleagues report that streams throughout the Midwestern Corn Belt are receiving insecticidal proteins that originate from adjacent genetically modified crops. The protein enters streams through runoff and when corn leaves, stalks, and plant parts are washed into stream channels.
Genetically-modified plants are a mainstay of large-scale agriculture in the American Midwest, where corn is a dominant crop. In 2009, more than 85% of U.S. corn crops were genetically modified to repel pests and/or resist herbicide exposure. Corn engineered to release an insecticide that wards off the European corn borer, commonly referred to as Bt corn, comprised 63% of crops. The tissue of these plants has been modified to express insecticidal proteins, one of which is commonly known as Cry1Ab.
Following an assessment of 217 stream sites in Indiana, the paper's authors found dissolved Cry1Ab proteins from Bt corn present in stream water at nearly a quarter of the sites, including headwater streams. Eighty-six percent of the sampled sites contained corn leaves, husks, stalks, or cobs in their channels; at 13% of these sites corn byproducts contained detectable Cry1Ab proteins. The study was conducted six months after crop harvest, indicating that the insecticidal proteins in crop byproducts can persist in the landscape.
Using these data, U.S. Department of Agriculture land cover data, and GIS modeling, the authors found that all of the stream sites with detectable Cry1Ab insecticidal proteins were located within 500 meters of a corn field. Furthermore, given current agricultural land use patterns, 91% percent of the streams and rivers throughout Iowa, Illinois, and Indiana ””some 159,000 miles of waterways””are also located within 500 meters of corn fields.
Rosi-Marshall comments, "Our research adds to the growing body of evidence that corn crop byproducts can be dispersed throughout a stream network, and that the compounds associated with genetically-modified crops, such as insecticidal proteins, can enter nearby water bodies."
After corn crops are harvested, a common agricultural practice is to leave discarded plant material on the fields. This "no-till" form of agriculture minimizes soil erosion, but it also sets the stage for corn byproducts to enter nearby stream channels.
Rosi-Marshall concludes, "The tight linkage between corn fields and streams warrants further research into how corn byproducts, including Cr1Ab insecticidal proteins, potentially impact non-target ecosystems, such as streams and wetlands." These corn byproducts may alter the health of freshwaters. Ultimately, streams that originate in the Corn Belt drain into the Mississippi River and the Great Lakes.
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Other authors on the PNAS paper included first-author Dr. Jennifer L. Tank (University of Notre Dame) and Drs. Todd V. Royer (Indiana University), Matthew R. Whiles (Southern Illinois University), Natalie A. Griffiths (University of Notre Dame), Therese C. Frauendorf (University of Notre Dame), and David J. Treering (Loyola University Chicago).
The Cary Institute of Ecosystem Studies is a private, not-for-profit environmental research and education organization in Millbrook, N.Y. For more than twenty-five years, Cary Institute scientists have been investigating the complex interactions that govern the natural world. Their objective findings lead to more effective policy decisions and increased environmental literacy. Focal areas include air and water pollution, climate change, invasive species, and the ecological dimensions of infectious disease. Learn more at www.caryinstitute.org