March 20, 2005


Risks of combined pesticide use uncertain

Three chemicals used in Ag-Mart's Immokalee field have been shown to cause deformities in lab animals.


Palm Beach Post Staff Writers

IMMOKALEE The long list of chemicals to be used on the crop was tacked to a dusty bulletin board on the edge of a tomato field.

It was in that field that three migrant farmworker couples say they worked during the first half of last year. Months later, between Dec. 17 and Feb. 6, all three women gave birth to children with serious birth defects.

The list, which included 38 products, was posted in accord with federal regulations. Some were as simple as soap.

But more than 30 of the products contained chemically active ingredients monitored by the Environmental Protection Agency. Nine of those chemicals were listed as Category 1, which means they are highly toxic. Three have been shown to cause birth defects in lab animals.

Nonetheless, the EPA had tested and approved the chemicals one at a time and found them safe for agricultural purposes, if used properly. But the chemicals are not used individually in the fields of Florida, or anywhere in U.S. agriculture. They often are employed by the dozen during the life of a crop.

Just how much is known about that combination of products? Can a mix of chemicals used in agriculture harm workers and possibly cause birth defects?

"There has not been much study on that," says Dr. Stuart Brooks, professor in the College of Public Health at the University of South Florida, Tampa. "I don't think anybody knows."

Joan Flocks of Gainesville, an attorney and former member of the state-sponsored Pesticide Exposure Surveillance Program, agrees.

"Almost no study has been done on that," Flocks says. "We also don't know about long-term exposure. And here we're talking about pregnant women and fetuses, the most sensitive of all of us. It's not good."

The EPA itself concedes that study of the topic the chemical combinations used in agriculture all over the United States is very new.

"This is something the EPA is starting to look at," concedes environmental protection specialist William Wooge. "We're learning the science as we do it.

"Our paramount concern is human health," Wooge says. "And we are aware that farmworkers are in the front lines of pesticide use."

The investigations being done by Wooge and other EPA scientists were mandated by the Food Quality Protection Act of 1996. But an overwhelming majority of the study, if not all of it, has involved the effect on water supplies and the food that reaches the consumer, not the threat to farmworkers who are the most at risk.

Shelley Davis of the Farmworker Justice Fund in Washington, who has long been angered by government pesticide policies, puts it bluntly.

"The farmworkers are being used as guinea pigs out there," Davis says. "There are alternatives available to the growers that would cost a little bit more. I think most consumers would be willing to pay a little bit more and not have to read about children being born with birth defects.

"But it's not happening," Davis says. "What goes on is a cost-benefit analysis. If the use of the chemical benefits the grower enough, then risks are taken with the workers."

It is not known that pesticide exposure caused the birth defects in the Immokalee infants, one of whom was born with no arms and legs, and another, a girl, who died after three days from massive, disfiguring deformities. The third has a deformed lower jaw and swallowing problems.

Company wants answers, too

State officials last week began to investigate the cases and will look at all possible causes, including genetic influences, drug intake, diet and pesticides. The company for which the couples worked, Ag-Mart of Plant City marketer of Santa Sweets tomatoes says it will cooperate.

"We are very open to any investigation into the causes of what happened," said company President Don Long. "We want to find out as much as anybody."

What is known is this:

All six parents worked for Ag-Mart in Immokalee and also in Ag-Mart fields in North Carolina, where they also were exposed to many pesticides.

Excessive exposure to pesticides by parents has resulted in an "increased risk of offspring having or dying from birth defects," according to the EPA.

According to the Florida Department of Health, excessive exposure to pesticides in humans can have immediate effects such as eye and skin irritation, nausea, headache, respiratory failure and loss of consciousness. The long-term concerns are liver damage, leukemia, non-Hodgkins lymphoma, skin and breast cancer, as well as low birth weight in infants.

Florida uses more pesticides per acre than any state in the country. At the same time, farmworker advocates say Florida has one of the least effective pesticide monitoring and enforcement programs in the country.

The Florida Department of Agriculture, the agency responsible for enforcing and investigating state and federal farmworker safety regulations, levied fines in only 7.6 percent of the cases where it found violations between 1993 and 2003.

In the case of Ag-Mart, the company was cited at least three times between 1999 and 2003 for violations of pesticide regulations. Those violations involved failure to provide protective equipment, failure to keep workers out of the fields for a prescribed time after agricultural chemicals had been used known as reentry intervals and failure to keep proper records of the use of chemicals. Those infractions occurred at other Ag-Mart fields throughout the state, and the company was never fined for them.

Mixed chemicals a danger?

The pesticides listed by Ag-Mart at the Immokalee field included insecticides, herbicides and fungicides. Three of the chemicals used metribuzin, avermectin and mancozeb have all been shown to cause deformities in lab animals.

Metribuzin caused low body weight in rat fetuses and loss of appetite in their mothers even at relatively low doses, according to an EPA study. The other two chemicals caused such deformities as cleft palates and club feet in lab animals, but only at extremely high doses.

All three substances were approved for use after being tested individually. But could their use in the same agricultural setting create uncharted dangers?

According to Florida pesticide experts, some chemicals when combined can create effects that they would not create individually.

"In other words, in some cases one plus one equals three," says Brooks, the USF public health professor. "A byproduct becomes the active ingredient."

Dr. Lora Fleming, an epidemiologist at the University of Miami, agrees.

"Once you combine chemicals, it can go either way: It can be better, but it can also be worse," Fleming says. "As far as I know, the EPA doesn't take that into account."

But Dr. Raymond Harbison, a toxicologist and professor of environmental and occupational health at the University of South Florida, thinks differently.

He concedes that the study of chemicals used in combination in agriculture is fairly new and that it is "an area of concern." But Harbison says experience with chemicals in other fields makes it unlikely that the substances could combine to cause mixtures harmful to humans.

"I'm not saying it's impossible, but it's remote," Harbison said.

He also says the differences in the birth defects of the three children make it "not likely" that they had the same cause. He says in previous cases of drugs causing birth defects such as thalidomide or fetal alcohol syndrome the defects were very similar in infants, as opposed to the three Immokalee cases.

Lax enforcement a concern

Stefan Korpalski, a consultant to the agricultural industry, who spoke to The Palm Beach Post for the Florida Fertilizer and Agrochemical Association, said he also thought that possible harmful effects of chemical combination may have been overstated. But Korpalski did have a concern. For the past several years, he has worked establishing standards for the number of hours or days that workers should stay out of fields after pesticides have been used. He acknowledges that those "reentry intervals" are not always honored and that is potentially dangerous to workers.

"Enforcement is not what it should be," Korpalski says. "There are so little resources available for good enforcement."

He also expressed doubts about the Florida system that put the Department of Agriculture in charge of that enforcement.

California's pesticide regulation program, which is seen as the most stringent in the country, is run as part of its Environmental Protection Agency. While Korpalski didn't endorse all aspects of the California system, he said it was preferable to Florida's.

"The focus is quite different when the entity in charge is agriculture," he says. "Under an environmental protection agency, such a program could focus more on the science, along with the concerns of agriculture."

He said that attention would lead to better enforcement of pesticide regulations.

Fleming of the University of Miami also worries about lax enforcement. She is particularly concerned about the violation of reentry rules combined with the high sensitivity of pregnant women and their fetuses to the pesticides.

"If a company breaks the rules, it should be on the company to prove that those women weren't affected by those chemicals," Fleming says.

"It shouldn't be up to the women to prove anything. Pregnant women should not have been exposed to that sort of risk at all."