生化玉米的毒素在美国的水流中被检测出来的论文:
http://www.businessweek.com/news ... ms-study-finds.html
Toxin From Biotech Corn Detected in U.S. Streams, Study Finds
September 28, 2010, 2:22 PM EDT
By Rudy Ruitenberg
Sept. 28 (Bloomberg) -- An insecticide produced by genetically modified corn was found in streams in the U.S. Midwest, according to research by the Cary Institute of Ecosystem Studies.
Samples at 217 stream sites in Indiana found the protein Cry1Ab, the toxin expressed by so-called Bt corn, in water at about a quarter of the locations, the Millbrook, New York-based institute said on its website, citing a study published this week in Proceedings of the National Academy of Sciences.
The insecticide enters waterways through runoff and when corn stalks, leaves and plant parts are washed into stream channels, the institute said. Indiana grows about 8 percent of the U.S. corn crop, according to the U.S. Department of Agriculture.
“The tight linkage between corn fields and streams warrants further research into how corn byproducts, including Cry1Ab insecticidal proteins, potentially impact non-target ecosystems,” said Emma Rosi-Marshall, an aquatic ecologist who was one of the authors of the study, in a statement.
These corn byproducts may alter the health of freshwater bodies, the institute said, adding that ultimately streams that originate in the Corn Belt drain into the Mississippi River and the Great Lakes.
Corn is made to produce the Cry1Ab protein, which is toxic to the European corn borer, by adding a gene from the soil bacterium Bacillus thuringiensis, or Bt. The European corn borer is the most damaging insect pest of corn in the U.S., with losses from plant damage and control costs exceeding $1 billion a year, according to the University of Minnesota.
The study was conducted six months after the corn harvest, indicating that the insecticide can persist in the environment, the Cary Institute said.
Repel Pests
The stream sites with detectable Cry1Ab toxins were all within 500 meters (1,640 feet) of a corn field, according to the study. Based on current farmland use, 91 percent of streams and rivers in Iowa, Illinois and Indiana are located within that same distance from a corn field, the institute said.
“Genetically modified plants are a mainstay of large-scale agriculture in the American Midwest,” according to the report.
More than 85 percent of U.S. corn in 2009 was genetically modified to repel pests, resist herbicide exposure or both, with 63 percent of the crop modified to protect against the European corn borer, according to the Cary Institute.
--Editors: John Deane, Dan Weeks.
To contact the reporter on this story: Rudy Ruitenberg in Paris at rruitenberg@bloomberg.net.
To contact the editor responsible for this story: Claudia Carpenter at ccarpenter2@bloomberg.net. |