Concerns have been raised as a Parkinson's "timebomb" could result in thousands developing the disease from a one commonly used chemical.
Used in dry cleaning, the toxic chemical could increase the risk of the progressive condition, according to a new study. Researchers say that people exposed to the industry solvent are 70 per cent more likely to receive a diagnosis.
The research analysed thousands of former marines stationed at Camp Lejeune in North Carolina where the water supply was contaminated with the chemical named trichloroethylene (TCE) as well as other volatile organic compounds. The dangerous chemical was also found in decaffeinated coffee, reports the Mirror.
California University's Professor Samuel Goldman explained: "Exposure to trichloroethylene in water may increase the risk of Parkinson's disease. Millions worldwide have been and continue to be exposed to this ubiquitous environmental contaminant."
Banned by the food and pharmaceutical industries since the 1970s, TCE was removed from dry cleaning in the mid 50s.
However, the chemical is still used in metal cleaning and degreasing as well as being used as an extraction solvent in the textile manufacturing industry.
The drinking water consumed at the marine camp was contaminated between 1953 and 1987 until testing uncovered the polluted wells.
Prof Goldman said: "Monthly median levels of TCE in the base's water supply were greater than 70-fold the permissible amount."
The team compared the number of Parkinson's cases among roughly 172,000 veterans from the camp and 168,000 peers at Camp Pendleton in California - where drinking water was clean.
Those analysed were mostly male and spent on average two years living at their respective bases in the 10 years between 1975 and 1985. Contamination was at its highest during these years.
The results suggest that more than three decades later a total of 279 veterans from Camp Lejeune and 151 from Camp Pendleton received a Parkinson's diagnosis.
This represents a prevalence of 0.33 and 0.21 per cent respectively.
Prof Golman said: "Computer models showed Camp Lejeune veterans had a 70 per cent higher risk of Parkinson's than Camp Pendleton veterans."
As much as a third of water supplies in the US overall have measurable amounts of TCE. This then leads to accumulation of the chemical in soil.
The dangerous element can be absorbed by humans through lungs, skin and intestines, with exposure possible through occupational usage, injection of contaminated food and water or during cooking and bathing.
Prof Goldman said: "Reflecting its environmental ubiquitousness, TCE has been broadly detected in human breast milk, blood and urine.
"It should be noted that in addition to the exposed service members studied here, hundreds of thousands of family members and civilian workers exposed to contaminated water at Camp Lejeune may also be at increased risk of Parkinson's, cancers and other health consequences.
"Continued prospective follow-up of this population is essential.This cohort study’s findings suggest the risk of Parkinson's is 70 per cent higher in veterans who were exposed to TCE and other VOCs 40 years ago.
"Trichloroethylene is a ubiquitous environmental contaminant used throughout the world since the 1920s. Many millions have been and continue to be exposed."
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