GM Free Cymru

Contamination of streams by BT crop detritus

It will, of course, be denied by the GM industry that this contamination has any biological impact. Monsanto et al have been saying that for years, and pretending that BT toxins only affect "target" organisms -- which is of course biological nonsense. The insecticide in GM crops (Bt) causes a strong immune response in any insect that can survive its toxicity. Any immune response in any insect causes cognitive impairment of that insect. We await further work on this -- to see what the actual measurable effects are in aquatic ecosystems.

Proceedings of the National Academy of Sciences USA, 107 (40), Oct 2010. Accepted by the Editorial Board August 31, 2010 (received for review May 20, 2010)

Occurrence of maize detritus and a transgenic insecticidal protein (Cry1Ab) within the stream network of an agricultural landscape

by Jennifer L. Tanka, Emma J. Rosi-Marshall,Todd V. Royer, Matt R. Whiles, Natalie A. Griffiths, Therese C. Frauendorf, and David J. Treering


Widespread planting of maize throughout the agricultural Midwest may result in detritus entering adjacent stream ecosystems, and 63% of the 2009 US maize crop was genetically modified to express insecticidal Cry proteins derived from Bacillus thuringiensis. Six months after harvest, we conducted a synoptic survey of 217 stream sites in Indiana to determine the extent of maize detritus and presence of Cry1Ab protein in the stream network. We found that 86% of stream sites contained maize leaves, cobs, husks, and/or stalks in the active stream channel. We also detected Cry1Ab protein in stream-channel maize at 13% of sites and in the water column at 23% of sites. We found that 82% of stream sites were adjacent to maize fields, and Geographical Information Systems analyses indicated that 100% of sites containing Cry1Ab-positive detritus in the active stream channel had maize planted within 500 m during the previous crop year. Maize detritus likely enters streams throughout the Corn Belt; using US Department of Agriculture land cover data, we estimate that 91% of the 256,446 km of streams/rivers in Iowa, Illinois, and Indiana are located within 500 m of a maize field. Maize detritus is common in low- gradient stream channels in northwestern Indiana, and Cry1Ab proteins persist in maize leaves and can be measured in the water column even 6 mo after harvest. Hence, maize detritus, and associated Cry1Ab proteins, are widely distributed and persistent in the headwater streams of a Corn Belt landscape.