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

Proc Natl Acad Sci U S A. 2010 Oct 12;107(41):17645-50. doi: 10.1073/pnas.1006925107. Epub 2010 Sep 27.

Abstract

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.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Agriculture
  • Bacterial Proteins / analysis*
  • Endotoxins / analysis*
  • Environmental Monitoring / statistics & numerical data*
  • Geographic Information Systems
  • Hemolysin Proteins / analysis*
  • Indiana
  • Insecticides / analysis*
  • Plant Components, Aerial / chemistry*
  • Plants, Genetically Modified / genetics*
  • Rivers / chemistry*
  • Water Pollutants, Chemical / analysis*
  • Zea mays / genetics*

Substances

  • Bacterial Proteins
  • Endotoxins
  • Hemolysin Proteins
  • Insecticides
  • Water Pollutants, Chemical
  • insecticidal crystal protein, Bacillus Thuringiensis