The jury may still be out as to how the consumption of genetically modified (GM) foods can impact human health, but another piece of the puzzle is becoming increasingly clear: GM crops are not very obedient! Rogue GM plants have been found in the wild, and a new study finds insecticides from GM crops present in streams across the U.S. Midwest.
University of Notre Dame ecologist Jennifer Tank and colleagues have found that streams throughout the Midwest have been polluted by transgenic materials from corn crop byproducts, even six months after harvest.
Transgenic corn is genetically engineered to create its own insecticide to deter crop pests. The researchers show that transgenic materials from corn enter streams in the agricultural Midwest and can be then transported downstream to other bodies of water. In the new study, Tank and colleagues looked into the fate and persistence of insecticidal proteins by surveying 217 stream sites in northwestern Indiana six months after crop harvest.
What they found was that corn crop byproducts were common in agricultural streams and that 86 percent of sites contained corn leaves, cobs, husks and/or stalks in the active stream channel. Using sensitive laboratory testing to measure the amounts of actual insecticidal proteins from the GM corn, they found the residues dissolved in stream water samples at 23 percent of the sites–and this is six months after the crop harvest.
Tank points out that a majority of streams in the Midwestern corn belt are located in close proximity of corn fields. Furthermore, the research found that consumption of GM corn byproducts reduced growth and increased mortality of stream insects. Stream insects are important prey for aquatic and riparian predators, and widespread planting of these GM crops has unexpected ecosystem-scale consequences.