Is a common industrial chemical fueling the spread of Parkinson’s disease?
A carcinogenic chemical widely used to degrease aviation components and heavy machinery could also be linked to Parkinson’s disease, according to a new research paper that recommends increased scrutiny of areas contaminated by the compound for a long time.
Trichlorethylene, or TCE, is a colorless liquid that has been used to remove dirt from jet engines, strip paint, and remove stains from shirts left at the dry cleaner. Decades of widespread use in the US have left thousands of sites contaminated by TCE.
In an article published Tuesday in the Parkinson’s Disease Journal, The authors hypothesize that this pollution may be contributing to the global spread of Parkinson’s, a neurological disorder characterized by uncontrollable tremors and slow movement. Although the authors were unable to prove a direct connection, they cited a number of other studies suggesting that TCE may play a role in the degenerative brain disorder and urged further research.
“When Dr. Parkinson described the condition in 1817 in London, he reported six people with the disease,” said Dr. Ray Dorsey, professor of neurology at the University of Rochester and lead author. “Two hundred years later, the global burden of disease is estimated to be more than 6 million people worldwide. So how do you go from six to six million? The rates are growing much faster than aging alone could explain. It has to be environmental factors. I think TCE and air pollution are major contributors.”
Although prolonged or repeated exposure to TCE is known to cause kidney cancer, according to the National Cancer Institutethe paper’s authors argue that a connection to Parkinson’s disease would greatly increase their risk, particularly for contaminated sites that have been converted to housing estates.
“When a patient reports a possible exposure to me, I Google their location and almost always find a contaminated site,” Dorsey said.
The paper draws on more than two dozen research papers documenting the apparent neurological effects associated with TCE exposure and highlights a series of Parkinson’s cases. Citing the pervasive nature of the chemical, the document references a plume of pollution that underlies a part of Newport Beach, which is considered one of California’s largest residential communities affected by chemical fumes from legacy pollution.
TCE was first linked to Parkinson’s disease symptoms in 1969 in a 59-year-old man who worked with the chemical for more than 30 years, according to the article. It was largely related to workplace exposure, including a woman working with the chemical while cleaning houses and factory workers degreasing and cleaning metal parts. A 2012 study of twins found that occupational or hobby exposure was associated with an approximately 500% increased chance of developing Parkinson’s disease.
TCE production in the US peaked in the 1970s, exceeding 600 million pounds per year. It was commonly used at military bases and industrial sites, and disposed of at hazardous waste facilities.
Today, up to a third of US drinking water supplies may contain TCE, according to the Environmental Protection Agency. But the chemical also threatens indoor air quality, as it can seep from the ground into homes through holes in the foundation, where it is then inhaled as vapor.
In southern California, a region facing a housing shortage, redevelopment of land contaminated by TCE and a host of other chemicals has raised alarm bells among community groups.
The Santa Susana Field Laboratory, the site where the rocket motors were tested in Ventura County’s Simi Hills, was once remote. Today, 700,000 people live within 10 miles of the inactive site, where the soil and groundwater are contaminated with more than 300 contaminants, including TCE.
Similarly, in Riverside County’s Jurupa Valley, development over the years has moved closer to the Stringfellow Acid Pits, a closed hazardous waste site that was managed by TCE.
“Studies have always focused on cancer. And we’ve always said that there are other secondary illnesses and illnesses that come along with this that they’re not realizing,” said Penny Newman, a Jurupa Valley resident and founder of the Center for Community Action and Environmental Justice.
“The site itself was isolated in a box canyon above the community, and there hadn’t been a lot of development there,” Newman said. “But as the city grew with freeways, they started looking for any property that was available. And it’s only in the last few years, people have started to look at how they can develop around the “side” of the site.
In Newport Beach, in Orange County, chemicals in the shallow groundwater were left behind by a former test range for missile systems.
From 1957 to 1993, Ford Motor Co. operated a 98-acre aviation campus where it developed tactical missile systems. Following the demolition of the facility, the site underwent environmental remediation and was subsequently redeveloped into residential properties. Some of these included multi-million dollar homes. However, some chemical contamination remained and migrated with the groundwater to surrounding areas.
Groundwater within Newport Beach is not used for drinking, and TCE vapor levels were not considered a public health threat at the time. However, in 2014, Region 9 of the US Environmental Protection Agency issued a memo on the dangers of breathing TCE vapors. Shortly thereafter, California revised its health thresholds for TCE exposure.
Since 2018, Ford-contracted consultants, under the supervision of the Santa Ana Regional Water Quality Control Board, have conducted soil vapor monitoring in the area surrounding the former site.
“Ford believes that access to a safe and clean environment is a basic human right, including for Newport Beach residents,” the company said in a prepared statement. “Since 1996, Ford has been working proactively with the Santa Ana Regional Water Quality Control Board to address volatile organic compounds in soil and groundwater. We have provided regular updates to the community and will continue to do so.”
So far, more than 350 residential properties and three commercial properties have had their indoor air sampled. Vapors of TCE and a related solvent, tetrachlorethylene or PCE, have been detected above detection levels in 129 homes. Air purifiers have been offered to about 30 homes where data suggested a vapor intrusion was taking place.
Outside the houses, a network of 424 underground monitors collect vapor measurements at depth. In some cases, these probes have measured TCE concentrations more than 100 times the California residential limit.
In it Bayridge Park and Belcourt Terrace CommunitiesIn two of the communities with the highest concentrations, Ford is working to install underground piping systems designed to treat underground vapors for about a year, which is expected to bring indoor TCE levels down to state standards, according to Jessica Law, an engineer. geologist of the water board.
“This is one of the wealthiest parts of the entire United States,” said Dorsey, who grew up in Newport Beach. “If this is happening in a resource-rich area, think about what is happening in a resource-poor area.”
Environmental advocates say that TCE exposure is preventable. New York and Minnesota have banned its use, and earlier this year the US EPA determined that TCE poses “an unreasonable risk of harm to human health,” a designation that paves the way for potential regulation.
In Jurupa Valley, the California Department of Toxic Substances Control continues to deal with TCE contamination that spilled from a long-closed former hazardous waste site. From 1956 to 1972, about 34 million gallons of liquid industrial waste was discharged into evaporation pools at the Stringfellow Acid Pits in a canyon in the Jurupa Mountains. The contamination escaped when floodwaters carried the contaminants off the site and into a community below.
The state spent millions of dollars installing a network of wells extract and treat a polluted water columnA. Despite substantial progress, monitoring in 2018 revealed that TCE vapors continued to exceed state health standards.
But after years of drought, which allowed more contaminated water to be treated and disposed of, locals now fear the contamination could be spread by rain and snowmelt.
“Everything is in that soil,” said Newman of Jurupa Valley. “So if you turn that on again and it becomes mobile through the groundwater, it will cause it to start going down (into the community) again.”