Many pesticides interfere with the nervous transmission in insects, whereas herbicides often mimic the hormones that control growth and development in plants. I suppose, in hindsight, we should have expected these chemicals to have some effects on humans as well.
Studies now report an alarming, higher incidence of Parkinson’s disease—one of the most debilitating neurodegenerative diseases in humans—which is related to long-term, low-level exposure to pesticides. In what are called retrospective studies, the risk of Parkinson’s disease increased by 1.6 times in individuals with exposure to any pesticide and 1.4 times with exposure to herbicides.
The herbicide paraquat was associated with a 2.2-fold increase in the incidence of Parkinson’s disease amongthose who have ever used the chemical. Organochlorine insecticides are also associated with Parkinson’s disease, and particularly alarming higher rates of incidence are observed with combinations of pesticides.
The studies of Parkinson’s disease are not alone. Other work suggests strong correlations between pesticide exposure and the risk of Alzheimer’s disease and amyotrophic lateral sclerosis (ALS – or Lou Gehrig’s Disease).
All of these studies should alarm us: when we put chemicals into the environment, they are designed to kill things – they may kill us. And there are painfully few long-term studies that document the impacts of pesticide exposure to humans.
Better living is not necessarily associated with chemistry.
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For more information see: Kamel, F. (2013). Paths from pesticides to Parkinson’s. Science, August 16, 2013.
Photo, taken on November 20, 2010, courtesy of the Wisconsin Department of Natural Resources via Flickr.
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