http://www.biosafety-info.net/article.php?aid=1053

.... 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...