High residues of glyphosate accumulate in Roundup Ready soybeans
Publication date: March 21, 2014
THIRD WORLD NETWORK BIOSAFETY INFORMATION SERVICE
Dear friends and colleagues,
Research published in the peer-reviewed journal Food Chemistry has found residues of glyphosate (and its breakdown product AMPA) in high concentrations in GM soybeans, but not in conventional or organic soybeans. The study examined 31 samples of soybeans grown within a defined area within the state of Iowa, USA.
GM soy engineered to be glyphosate resistant is the number one GM crop plant. The herbicide glyphosate is the most widely used herbicide globally. For herbicide-resistant GM plants, herbicide co-technology is an integral part of the production system and will always be used by the farmer.
However, little attention has been given to the residues of herbicides and their metabolites that can potentially accumulate in the final product. Chemical residues, if present, are important because they are clearly a part of a plant’s composition, and they may add toxic properties to the final plant product either by itself or by affecting the plant metabolism. (There has been increasing research demonstrating the potential health impacts of glyphosate.)
The authors suggest that the increased use of glyphosate on Roundup Ready soybeans in the US, which has contributed to the selection of glyphosate-tolerant weeds, and resulted in a response of increased doses and/or more applications used per season, may explain the plant tissue accumulation of glyphosate.
Lack of data on pesticide residues in major crop plants is a serious gap of knowledge with potential consequences for human and animal health. The authors therefore recommend the following:
(i) increased effort on sampling and testing crop material from the market;
(ii) testing for possible dose-response effects of chemical residues in long-term feeding studies;
(iii) inclusion of pesticide residue measurements and safety testing in the regulatory system for risk assessment of GM crops; and
(iv) further research on the indirect ecological effects of herbicides and pesticides.
The study also showed that different agricultural practices may result in a markedly different nutritional composition of soybeans, with organic soybeans having the healthiest nutritional profile compared to GM and conventional soybeans.
In sum, the data demonstrated that different agricultural practices lead to markedly different end products, i.e. there is no substantial equivalence between the three management systems of herbicide resistant GM, conventional and organic agriculture.