California Scientists Claim Link Between Pesticides and Parkinson’s

University of California researchers studying rural residents in California’s Central Valley have apparently found that those drinking water from private wells have a 90 percent higher risk of developing Parkinson’s disease if the wells are near fields sprayed with certain pesticides. Nicole Gatto, et al., “Well Water Consumption and Parkinson’s Disease in Rural California,” Environmental Health Perspectives, July 31, 2009. Supported by the National Institute of Environmental Health Sciences, the study estimated potential well water contamination on the basis of agricultural application records for 26 pesticides and involved 368 cases and 341 population controls enrolled in the Parkinson’s Environment and Genes study.

The researchers found that people with the disease “were more likely to have consumed private well water, and had consumed it on average 4.3 years longer” than those without the disease. The strongest link to disease was found in areas sprayed with propargite, a pesticide used mostly on nuts, corn and grapes. Strong links were also found for the insecticides methomyl and chlorpyrifos, which was banned for residential use in 2001, but is still widely used on cotton, corn, fruit trees, and other crops. Methomyl is used on alfalfa. According to a news source, while the study fills some research gaps, scientists did not test the private wells and thus do not specifically know what each person may have been exposed to. See Environmental Health News, August 5, 2009.