YAKIMA HERALD-REPUBLIC December 7, 2006
Air samples' pesticide levels raise concern By LEAH BETH WARD A limited air-sampling survey conducted by farm-worker advocates in April outside two homes near Yakima Valley orchards found what could be unacceptable levels of a pesticide that can cause damage to the central nervous system of children. Grower representatives quickly criticized the report, titled "Poisons on the Wind," as unscientific. It was released Wednesday by the Farm Worker Pesticide Project of Seattle. Two university scientists, meanwhile, drew both positive and negative conclusions, saying the report represents an important development in the discussion of pesticide exposure but falls short of anything definitive. The "community air monitoring" survey looked at chlorpyrifos (pronounced klor-PIE-ra-fus), a key ingredient in the pesticide Lorsban that's widely used as an insecticide in early spring when fruit trees are dormant. The chemical is a kind of organophosphate that in cases of excessive exposure can depress certain enzymes necessary for everything from proper breathing to muscle coordination. Symptoms of overexposure range from dizziness to difficulty breathing, and even paralysis. The chemical was present at some level on all 21 days of air monitoring at two separate homes, one in Cowiche and the other in Tieton. The residents -- one a farm worker, the other a former farm worker -- volunteered to collect outdoor air samples during spraying season using devices called "drift catchers," relatively simple air-monitoring devices. Children ranging in age from 2 to 8 were present. At the Cowiche home, which is 57 feet from an apple orchard, there were eight days, or 38 percent of the time, when levels of the pesticide exceeded doses considered acceptable for a 1-year-old child by the federal Environmental Protection Agency. Those samples were analyzed by Susan Kegley, a senior scientist at Pesticide Action Network of North America, a San Francisco-based nonprofit that works to replace pesticides with alternatives. The highest concentration in a 24-hour period was 3.4 times the acceptable level. Duplicate samples from the Cowiche site were tested by EMA, a commercial laboratory in Brea, Calif., which detected unacceptable levels for six days, or 29 percent of the time. At the Tieton home, which is surrounded by orchards, the farm-worker lab found chlorpyrifos exceeded acceptable levels on eight days, or 38 percent of the time. The highest concentration was 2.8 times the safe level. EMA Labs didn't analyze the Tieton samples. Authors of the report declined to identify the residents or their addresses. But they said their findings represent the first significant study of the prevalence of pesticides around orchards. "We think this is groundbreaking," Carol Dansereau, director of the Farm Worker Pesticide Project, said in a telephone interview. Dan Fazio, director of employer services for the Washington Farm Bureau, said the circumstances surrounding the air monitoring weren't realistic. "Would you stand 15 yards from a field when they are spraying?" he said. Richard Fenske of the University of Washington, who has long studied pesticide exposure, said it's unlikely an infant would be in the backyard of a home for 24 hours in April -- the assumption of the report. "They sampled the wrong place. If you want to estimate the risk of a 1-year-old child, you need to do it indoors," said Fenske, who directs the Pacific NW Center for Agricultural Safety and Health. Still, Fenske said the report could be an "important call to arms" to continue comprehensive studies. Allan Felsot, professor of entomology at Washington State University-Tri-Cities, said the EPA standard itself has built-in safety factors. He calculated from the report that even the highest levels of exposure found in the samples would still be 300 times less than the amount of the pesticide needed to cause a change at the molecular level. "I look at this data and say there's nothing to worry about there. This is good news," Felsot said. Dansereau said the group isn't pretending to be the last word on the problem of pesticide drift. "We just want to know what people are breathing and we have a right to do that. We'd love to see more comprehensive studies," she said. Dansereau said the group was motivated to collect its own samples, in part, because the state Department of Agriculture dropped a plan early this year to require pesticide applicators to give 48 hours advance notice to places such as day care centers before spraying highly toxic chemicals next to their property. The agency determined that existing prohibitions on spraying were sufficient to protect the public but retained the option of running a pilot notification program. Organophosphates like chlorpyrifos can depress levels of cholinesterase, an enzyme critical to proper nervous system function. Children are particularly vulnerable to central nervous system problems from organophosphates. The journal Pediatrics published a study this week showing that children exposed before birth to chlorpyrifos had significantly poorer mental and motor development by age 3, and were at increased risk for behavior problems. EPA banned the use of chlorpyrifos in residential products six years ago because of the risk to children. The average application of chlorpyrifos is from one to three pints per acre. Actual acreage in the state treated with the pesticide has declined but the tree-fruit industry hasn't yet found an acceptable substitute.
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