Pesticides and TCE linked to Parkinson's disease
TWO YEARS of heavy exposure to the solvent trichloroethylene (TCE), may increase the risk of Parkinson’s disease by 70%. TCE is primarily used to degrease industrial metal parts by heating it in degreasing tanks to create a vapor that dissolves the grease. Once TCE enters the soil or groundwater, it can persist for decades.
A large-scale study led by UC San Francisco and the San Francisco VA Medical Center, compared Parkinson’s diagnoses in approximately 160,000 Navy and Marine veterans. Just over half came from Camp Lejeune in North Carolina, where TCE was used to degrease military equipment and water was contaminated; the remainder came from Camp Pendleton in California, where the water was not contaminated.
Of 430 veterans diagnosed with Parkinson’s, the Lejeune veterans’ risk was 70% higher than the Pendleton veterans. On average, service length at both camps was around two years from 1975 to 1985.
Meanwhile, researchers at UCLA Health and Harvard identified 10 pesticides that significantly damaged neurons implicated in the development of Parkinson’s disease.
While environmental factors such as pesticide exposure have long been linked to Parkinson’s, it has been harder to pinpoint which pesticides may raise risk.
Through a novel pairing of epidemiology and toxicity screening researchers were able to identify 10 pesticides that were directly toxic to dopaminergic neurons. The neurons play a key role in voluntary movement, and the death of these neurons is a hallmark of Parkinson’s.
Co-exposure of pesticides typically used in combinations in cotton farming were found to be more toxic than any single pesticide.
The 10 pesticides identified as directly toxic to these neurons included: four insecticides (dicofol, endosulfan, naled, propargite), three herbicides (diquat, endothall, trifluralin), and three fungicides (copper sulfate [basic and pentahydrate] and folpet). Most of the pesticides are still in use today.
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