Study affirms benefits of organic farming. (Environmental Intelligence).

A recent study confirms what proponents of organic farming have long argued: that organic foods carry less pesticide residue than conventionally grown foods. Organic standards prohibit farmers from using synthetic pesticides, but few studies to date have compared the pesticide levels of organic and nonorganic foods.

The study, published in the May 2002 issue of the food science journal Food Additives and Contaminants, found that organically grown foods were about one-third as likely to carry pesticide residues as the conventionally growls samples. All samples with traces of residue were within government limits, but in cases where organic produce tested positive, the trace amounts were minuscule. For example, the average organic spinach sample carried 0.008 parts per million of the insecticide omethoate, whereas the average conventional spinach sample carried 0.069 parts per million. The report also found that conventionally grown samples were six times more likely to contain residues of multiple pesticides, which can exacerbate the health effects of each chemical.

The study attributes the chemical traces on organic crops to drift from neighboring conventional farms and previous contamination of water and soil with long-lived pesticides, many of which were banned decades ago. For instance, when the researchers eliminated the highly persistent organochlorine pesticides, such as DDT, from the analysis, the percent of organic samples with at least one residue dropped from 23 to 13 percent.

"We now can say with confidence that organic farming systems help reduce exposure to pesticides in the human diet," said Charles Benbrook, one of the study's authors. The report analyzed more than 94,000 organic and conventional food samples of 20 different crops in the United States. The data were collected over the last decade by the U.S. Department of Agriculture, the California Department of Pesticide Regulation, and the New York-based Consumers Union.