Widespread Chemical May Increase Parkinson’s Disease Risk

A chemical commonly used in dry cleaning and to degrease metal has been linked to a higher risk of Parkinson’s disease.

For around a century, trichloroethylene — or TCE — has been used widely. Now, an international group of researchers says TCE might be an “invisible cause” of Parkinson’s.

The chemical also has been linked to cancer, miscarriages and congenital heart disease.

In a hypothesis paper published in the Journal of Parkinson’s Disease, the researchers note that studies of mice and rats have found that TCE easily enters the brain and body tissue. High doses can damage mitochondria, the part of cells that produce energy.

The animal studies also have found that exposure to TCE triggers the selective loss of dopamine-producing nerve cells. That loss is a classic sign of Parkinson’s disease in humans.

While those with direct exposure to TCE have been found to have a higher risk of Parkinson’s, the researchers note that millions of others “encounter the chemical unknowingly through outdoor air, contaminated groundwater, and indoor air pollution.”

TCE has been used as a solvent in industrial, consumer, military and medical applications. Among other things, it has helped:

• Decaffeinate coffee
• Remove paint
• Correct typewriting mistakes
• Clean engines
• Anesthetize patients

The peak of TCE use was in the 1970s. However, it still is used to degrease metal and in spot dry cleaning, the researchers say.

TCE also is present in about half of the most toxic Superfund sites — which are areas so contaminated with hazardous substances that the federal government now oversees them — according to the researchers.

Two states — New York and Minnesota — have banned the use of TCE. However, the researchers say more needs to be done to protect people from TCE. According to a summary of their findings:

“They note that contaminated sites can be successfully remediated and indoor air exposure can be mitigated by vapor remediation systems similar to those used for radon. However, the U.S. alone is home to thousands of contaminated sites and this process of cleaning and containment must be accelerated.”

Ultimately, the researchers say they would like to see a ban on the use of TCE in the U.S.