A widely used cleaning chemical (even in dry cleaning!) has been linked to Parkinson's disease by an international team of researchers. In a piece published in the Journal of Parkinson's Disease, they built a strong case that the chemical trichloroethylene (TCE) is one of the causes of Parkinson's disease. This is based on the existing evidence (both human and animal).
Trichloroethylene was widely used in the past (600 million lbs. per year at its peak in the 1970s), and is still widely used. It is environmentally persistent, and contaminates soil, air, and water. Vapors from underground water and soil contamination seep out into homes, schools, and workplaces. It is known to be carcinogenic (cancer causing) and associated with numerous cancers and other health harms, including birth defects.
TCE has had numerous industrial, consumer, military, and medical applications. For example, it is used in dry cleaning clothes, removing paint, as a degreaser, carpet cleaner, and engine cleaner. It even was used to produce decaffeinated coffee in the past! Many US sites are now contaminated with TCE, including military bases.
The scientists point out that Parkinson's disease has increased so much (by 500%) that there must be exposure to something else (or more than 1 thing), and they find a strong link to TCE. They refer to Parkinson's as "the world's fastest growing brain disease".
By the way, a number of other toxic chemicals are associated with Parkinson's disease, (e.g., some pesticides, some drugs), long-term welding exposure, and even head trauma.
The researchers urge banning both the production of TCE and its use, urge the clean up sites that are contaminated with TCE, and more research.
Excerpts from Medical Xpress: Common dry cleaning chemical linked to Parkinson's
A common and widely used chemical may be fueling the rise of the world's fastest growing brain condition—Parkinson's disease. For the past 100 years, trichloroethylene (TCE) has been used to decaffeinate coffee, degrease metal, and dry clean clothes. It contaminates the Marine Corps base Camp Lejeune, 15 toxic Superfund sites in Silicon Valley, and up to one-third of groundwater in the U.S. TCE causes cancer, is linked to miscarriages and congenital heart disease, and is associated with a 500% increased risk of Parkinson's disease.
In a hypothesis paper in the Journal of Parkinson's Disease, an international team of researchers—including University of Rochester Medical Center (URMC) neurologists Ray Dorsey, MD, Ruth Schneider, MD, and Karl Kieburtz, MD—postulate that TCE may be an invisible cause of Parkinson's. In the paper they detail the widespread use of the chemical, the evidence linking the toxicant to Parkinson's, and profile seven individuals, ranging from a former NBA basketball player to a Navy captain to a late U.S. Senator, who developed Parkinson's disease either after likely working with the chemical or being exposed to it in the environment.
A ubiquitous and widespread industrial pollutant
TCE was a widely used solvent employed in a number of industrial, consumer, military, and medical applications, including to remove paint, correct typewriting mistakes, clean engines, and anesthetize patients. Its use in the U.S. peaked in the 1970's, when more than 600 million pounds of the chemical—or two pounds per American—were manufactured annually. Some 10 million Americans worked with the chemical or other similar industrial solvents. While domestic use has since fallen, TCE is still used for degreasing metal and spot dry cleaning in the U.S.
TCE contaminates countless sites across the country. Half of the most toxic Environmental Protection Agency's Superfund sites contain TCE. Fifteen sites are in California's Silicon Valley where the chemicals were used to clean electronics and computer chips. TCE is found in numerous military bases, including Camp Lejeune in North Carolina. From the 1950s to the 1980s a million Marines, their families, and civilians that worked or resided at the base were exposed to drinking water levels of TCE and perchloroethylene (PCE), a close chemical cousin, that were up to 280 times above what is considered safe levels.
TCE and Parkinson's disease
The connection between TCE and Parkinson's was first hinted at in case studies more than 50 years ago. In the intervening years, research in mice and rats have shown that TCE readily enters the brain and body tissue and at high doses damages the energy-producing parts of cells known as mitochondria. In animal studies, TCE causes selective loss of dopamine-producing nerve cells, a hallmark of Parkinson's disease in humans.
Individuals who worked directly with TCE have an elevated risk of developing Parkinson's. However, the authors warn that "millions more encounter the chemical unknowingly through outdoor air, contaminated groundwater, and indoor air pollution."
The chemical can contaminate soil and groundwater leading to underground rivers, or plumes, that can extend over long distances and migrate over time. One such plume associated with an aerospace company on Long Island, New York, is over four miles long and two miles wide, and has contaminated the drinking water of thousands. Others are found everywhere from Shanghai, China, to Newport Beach, California.
Beyond their risks to water, the volatile TCE can readily evaporate and enter people's homes, schools, and work places, often undetected. Today, this vapor intrusion is likely exposing millions who live, learn, and work near former dry cleaning, military, and industrial sites to toxic indoor air. Vapor intrusion was first reported in the 1980s when radon was found to evaporate from soil and enter homes and increase the risk of lung cancer. Today millions of homes are tested for radon, but few are for the cancer-causing TCE.