PALM BEACH POST

December 25, 2006

Study links pesticide to learning disorder

By John Lantigua And Christine Stapleton, Palm Beach Post Staff Writers

A study by Columbia University scientists has established a link between learning disorders in children and a pesticide that has been used extensively on sweet corn, one of Palm Beach County's major crops.

But local and state agricultural officials say the insecticide, chlorpyrifos, does not pose a threat to consumers because it does not leave dangerous levels of residue on the corn. The principal danger may be to families living and working around where the corn is grown who could be affected when the insecticide is applied or the corn picked.

Palm Beach County grows more sweet corn than any county in the nation and bills itself as the "Sweet Corn Capital of the World."

About 25,000 acres in the western reaches of the county are sown with the crop. Agricultural scientists say most of it is planted away from populated areas, although some fields are close to municipalities in the Glades.

"We don't put houses in the middle of our cornfields the way they do in the Midwest, so I don't see that much of a danger, although there are some fields closer to towns, on the outskirts of places like Belle Glade," said Richard Raid, a plant pathologist with the Everglades Research Center in the Glades

The chemical, marketed as Lorsban, can be sprayed from the air or the ground, or applied in granular form.

University of Florida entomologist Greg Nuessly said growers planting fields near populated areas do not use crop dusters to spread Lorsban.

"They are sensitive to the threat of drift, and they use the other methods," he said.

A recent study in Washington state near apple orchards where chlorpyrifos was used found unsafe levels of the chemical in the air in yards near the orchards, according to the Pesticide Action Network, a nonprofit group that collaborated in the study. No such tests have been conducted in Florida.

Sale of chlorpyrifos for residential pesticide use was banned by the federal Environmental Protection Agency as of Dec. 31, 2001, except for childproof containers such as roach traps. The ban followed tests that showed adverse effects on lab animals and other tests that found traces of the chemical in children's blood samples.

The insecticide also has been outlawed for use on certain fruits and vegetables, including tomatoes. In fields of sweet corn, it is used to kill worms that attack the crop.

While the EPA, which helped finance the Columbia study, has maintained that current approved uses of the pesticide are safe, the agency said it will take another look.

"EPA will review the report by the scientists at the Columbia University Center for Children's Environmental Health ... to determine if further investigation or regulatory actions are needed," the EPA said in response to inquiries by The Palm Beach Post.

The study, published this month in Pediatrics, the journal of the American Academy of Pediatrics, was conducted in New York City, where chlorpyrifos was widely used for residential pest extermination until the 2001 ban.

The study targeted children born between 1998 and May 2002, shortly after the product was removed from the shelves for home use. Blood samples taken from participating mothers and children showed that at least 64 percent contained some amount of the chemical.

The study says that unsafe levels of the chemical cause delays in learning rates and obstruct physical coordination in some children up to age 3.

The scientists said children exposed to the pesticide, prenatally or in their first years, also are more likely to incur behavioral problems, specifically attention deficit hyperactivity disorder.

In 2004, the latest figures available from the National Agriculture Statistical Service, 41 percent of the sweet corn acreage in Florida was treated with chlorpyrifos. With at least two-thirds of the state's sweet corn coming from Palm Beach County, it is assumed most of that use is local.

Application of Lorsban has decreased in recent years as cheaper and less-toxic products have come on the market.

As late as 2000, 80 percent of sweet corn was treated with the product.

"We don't use it as much we once did, but it still has its uses," said William McKinstry, owner of WM Farms in Loxahatchee, where he plants about 3,000 acres of sweet corn. "We would rather not lose the use of it. Bugs develop tolerances to chemicals, and you want all the choices you can have."

According to the Florida Department of Agriculture and Consumer Services, chlorpyrifos is also approved for mosquito control. State records indicate that only small portions of North Florida, in Suwanee and Volusia counties, use it for that purpose.