The link, which I've already put up in a previous post on this thread:
In 2010, the National Organic Program worked with the USDA Agricultural Marketing Service’s Science and Technology Program to evaluate pesticide residues on USDA organic produce. The study involved 571 domestic and foreign fruit and vegetable samples bearing the USDA organic seal, which were obtained from retail establishments across the United States. Using sensitive equipment, an accredited Government laboratory tested each sample for approximately 200 pesticides typically used in conventional crop production.
Of these 571 samples, 96 percent were compliant with USDA organic regulations (see Figure ES1). This means that the produce either had no detected residues (57 percent) or had residues less than 5 percent of the EPA tolerance (39 percent). Four percent of the tested samples contained residues above 5 percent of the EPA tolerance and were in violation of the USDA organic regulations. The findings suggest that some of the samples in violation were mislabeled conventional products, while others were organic products that hadn’t been
adequately protected from prohibited pesticides. The National Organic Program is working with certifying agents to provide additional scrutiny in these areas.