Guest guest Posted October 4, 2000 Report Share Posted October 4, 2000 Allergy sufferers don't cotton to defoliants, but link is unclear By Barbara The Fresno Bee (Published October 2, 2000) The low hum of crop-dusting planes, dropping out of the sky like steel dragonflies over cotton fields in the San Joaquin Valley, signals the beginning of cool nights, foggy mornings -- and sneezing and wheezing. Each fall, doctors have waiting rooms filled with red-eyed, stuffy-nosed patients whose symptoms seem to ebb and flow in rhythm with the beginning and end of cotton defoliant season. Complaints about the chemicals -- sprayed on cotton to strip the plants of their leaves -- are about as old as the practice of mechanical harvesting, but cotton farmers say they are being accused, tried and convicted on circumstantial evidence that hasn't been tested by scientific research. " I sure don't want to pooh-pooh people's symptoms, " said Betancourt, a westside cotton farmer. " But if it's just anecdotal -- accusations by circumstantial evidence -- maybe we need to do an objective study and nail this thing down. " Doctors are the first to admit they don't have proof that defoliants are the cause of their patients' respiratory distress. They can only go by what they see in their offices during the months of September and October, when cotton is defoliated. " Almost all of my asthma patients and patients with sinus problems, they really get worse this time of year, " said Dr. Malik Baz, an allergy specialist at the Allergy Center in Fresno. But Baz admits his patients' misery could have as much to do with nature as man's manipulation of his environment. Weed pollen counts go up in the fall, as does the number of mold spores. Defoliants, he said, are just another substance to factor into the mix of respiratory irritants in the air. Without health studies, it's hard to know whether blaming defoliants for respiratory problems is justified, he said. Most studies of cotton defoliants look at occupational exposures for workers in the fields and not at the potential health risks of exposure to chemicals floating in the air or attached to dust particles. Pesticide watchdogs say information is lacking on the effects of breathing airborne defoliants, but they argue the sheer number of chemicals being sprayed on cotton fields in the Valley makes it probable that people are being exposed. Neurotoxin worries some Cotton farmers depend on chemicals to strip leaves that would clog mechanical harvesters and stain cotton green. The Pesticide Use Report, issued by the California Department of Pesticide Regulation, shows that 835,449 pounds of four of the most widely used chemicals were sprayed to defoliate Fresno County's 145,000 acres of harvested cotton in 1999. The top four defoliants: Sodium chlorate, 569,807 pounds; S,S, S-tributyl phosphorotrithioate (DEF), 156,754 pounds; Paraquat dichloride, 98,834 pounds; and Thidiazuron (Ginstar EC), 10,054 pounds. Of particular concern to environmentalists is the use of the organophosphate known as DEF. Organophosphates are neurotoxins that disrupt the transmission of nerve signals. DEF is " a nasty one. It's not one you want to be next to, " said Kegley, a staff scientist at Pesticide Action Network, an environmental activist group working to reduce the use of pesticides. Little research has been done on the effects of breathing organophosphates, but a 1999 study of DEF by the state Department of Pesticide Regulation found little risk from breathing the chemical in ambient air around cotton farms. The study showed " in terms of short-term exposure, the levels of exposure to DEF were very low, " said Jay Schreider, DPR primary state toxicologist. However, the foul odor associated with DEF could be smelled at very low concentrations. DEF is readily degraded to n-butyl mercaptan, a substance that gives off the smell of rotten eggs that is similar to the odor added to natural gas. The DPR report said offensive odors can trigger symptoms in people, such as headaches and nausea. The study said reports of eye and lung irritation by people in communities near cotton fields may be due to n-butyl mercaptan, but " no reliable air monitoring data for n-butyl mercaptan was available. " Cheryl Gorman can't ignore the smell of rotten eggs on her way to and from work as an elementary teacher in Kerman. She has a stuffed nose and sinus headache during most of the fall, while cotton fields around the school are being defoliated. " I just know, during this time of the year, I'll be taking my allergy medicine and treating my allergy symptoms, " Gorman said. In the past few years, organophosphates have caused fewer complaints because manufacturers changed formulas to eliminate the tell-tale rotten egg or sulfuric odor. The pesticide, one of the most regulated, cannot be applied within a half-mile of residential areas and when winds are higher than 10 mph. But the defoliants remain an environmental concern, Kegley said. " Only pure, clean air belongs in our lungs. " Newer materials, which are less volatile, are gaining favor with farmers, said Ron Vargas, county director and farm adviser in the Madera County Office of the University of California ative Extension. " What I see is five years down the road, we're going to have materials that have been developed that are going to seriously mitigate this problem, " he said of people complaining about defoliants causing headaches and respiratory problems. Betancourt is using the defoliant Ginstar on his Pima cotton. " We use a lot less of the phosphate -- which is the one that smells the worse -- than we ever have before because there are alternatives that weren't there before, " he said. He questions widespread claims that pesticides cause congestion and sinus headaches. A year ago, he said, he had people complaining about headaches a week before any cotton fields in the area were defoliated. How could someone, he said, living 60 miles away in Clovis, be affected by the crop dusting he does on his cotton fields in Cantua Creek and Tranquillity? If test results showed the chemical in measurable quantities in the air in Clovis, " I'd say you've got the smoking gun, " he said. " Otherwise, I would look at other stuff. " The Central Valley has an air-quality problem, especially during stagnant, hot fall days, Betancourt said. " I would suspect there are worse things in the air than the defoliant spray. " But allergists say it may not take a high concentration of chemicals to trigger allergic responses in patients who are extremely sensitive to irritating substances, such as dust, pollen, mold spores, perfumes -- and chemicals. In the patient who is not sensitive, the body may not recognize the defoliant as a big enough threat to launch an all-out assault by secreting more mucus to trap the offending particles and coughing to push them out. But for the patient who is hypersensitive to irritants, it could cause coughing and the bronchial tubes to spasm, said Dr. A.M. Aminian with the Allergy Institute of Fresno. " The best thing for everyone to do is to avoid the irritants to the bronchial tubes, " Aminian said. " And that includes any irritant chemicals or fumes. " Defoliants' role is unclear If fewer pollen particles and mold spores were in the air, it's possible breathing tiny amounts of defoliants wouldn't bother his patients, Baz said. But, with high pollen and mold counts, they're primed and ready to react to any irritant. Without more studies on the effects of defoliants, it's hard to know whether the chemicals are to blame for the wheezing and sneezing, he said. " There are just no good studies. " Quote Link to comment Share on other sites More sharing options...
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