Pesticide Found In Food Decades After Use

by Beverly Hassell

The finding is reported in the May 15 print edition of the Journal of Agricultural and Food Chemistry. The report shows that although food contains small amounts of chlordane, the compound accumulates in the human body and can lead to digestive and nervous system disorders.

All 12 of the vegetables included in the study absorbed some of the compound, according to Mary Jane Incorvia Mattina, Ph.D., lead researcher of the report. Edible portions of carrots, potatoes, beets, spinach, lettuce, dandelion and zucchini absorbed the largest amounts of chlordane. Lesser amounts were found in the edible portion of beans and eggplant. Tomatoes, peppers and corn took in some chlordane at the roots, but did not transfer it to the edible portion of the vegetables. Fruits do not seem to be similarly affected, according to previous research.

You can substantially reduce the chances of consuming chlordane -- a colorless, tasteless compound still affecting foods grown where it was used -- by washing food in water before eating it, said Mattina, head of the department of analytical chemistry at the Connecticut Agricultural Experiment Station in New Haven, Conn.

The U.S. Environmental Protection Agency banned chlordane, used to control termites and other insects, in 1988. But because it was so widely used, nearly all farms -- including organic farms -- are affected. It is impossible to tell whether produce is contaminated just by looking at it.

The report is the first study of plant absorption of aged chlordane, part of a family of chemicals called persistent organic pollutants. Technical chlordane, a synthetic pesticide made up of 147 different components, was once widely used at high concentrations in gardens and commercial farms throughout the United States and Mexico. It has a half-life of 22 years in soil, according to Mattina.

"An informed consumer is a better consumer," Mattina added. "This information can be used to take the relatively small dietary intake (of chlordane) and make it even smaller."

Approximately six grams of the substance, deemed a possible human carcinogen by the EPA, can be fatal, according to the U.S. Centers for Disease Control and Prevention in Atlanta.

The study found that carrots grown in highly chlordane-contaminated soil contained maximum levels of approximately five micrograms of chlordane per gram of peel. The rest of the carrot contained only trace amounts of the compound. At that rate, it would take eating more than one million carrots to even approach dangerous levels.

While peeling affected root crops can significantly reduce their chlordane content, other foods retain the chemical until they are eaten. Only "deep plowing" to dilute the amount of chlordane in the soil can stop the uptake, Mattina said.

"The main recommendation is to wash the foods you are going to eat, and not to plant near a house foundation that could have been treated with chlordane," she said. "If you take these precautions, you shouldn't have any cause for concern."