The safety of municipal water supplies represents one of the most fundamental public health responsibilities facing local governments. In recent years, scientific research has drawn increasing attention to the presence of industrial solvents in water systems, particularly trichloroethylene (TCE), and their potential links to serious neurological diseases. Trichloroethylene can cause cancer according to an independent committee of scientific and health experts. It can cause developmental toxicity and male reproductive toxicity according to The Environmental Protection Agency (EPA).

While TCE contamination has been documented in water supplies across North America, questions remain about the adequacy of current security measures and oversight mechanisms. This article examines the evidence connecting TCE to disease, the vulnerability of water processing infrastructure, and the case for strengthened municipal oversight.

What is Trichloroethylene (TCE)?

Trichloroethylene is a colorless, volatile organic compound that has been widely used in industrial applications since the early 20th century. Its primary uses have included metal degreasing, dry cleaning, and vapor degreasing in manufacturing processes. TCE's widespread industrial application has made it one of the most frequently detected groundwater contaminants in the United States and other developed nations.

Unlike many industrial chemicals that remain contained within manufacturing facilities, TCE's volatility and solubility allow it to migrate through soil and groundwater systems, potentially contaminating drinking water sources. The EPA identified TCE as a probable human carcinogen in 1989, yet its presence in water supplies persists in numerous communities.

The Scientific Evidence: TCE and Neurological Disease

In recent years, epidemiological research has strengthened the case that chronic exposure to TCE and similar organic solvents may be associated with increased risk of Parkinson's disease and other neurodegenerative conditions. A landmark 2012 study published in Environmental Health Perspectives found that individuals with occupational or environmental exposure to TCE demonstrated a significantly elevated risk of developing Parkinson's disease compared to unexposed populations. This research, conducted across multiple regions, provided some of the first systematic evidence linking this industrial solvent to neurotoxic effects in humans.

The mechanism of TCE's neurotoxicity involves its ability to penetrate the blood-brain barrier and accumulate in neural tissue. Once present in the central nervous system, TCE metabolites can generate oxidative stress and mitochondrial dysfunction—cellular processes implicated in the pathogenesis of several neurodegenerative diseases. The research literature increasingly suggests that organic solvent exposure represents a potential environmental risk factor for Parkinson's disease, Alzheimer's disease, and possibly other neurodegenerative conditions.

Moreover, TCE's chemical properties may enhance its affinity for certain biological systems. Some research has suggested that individuals with compromised immune function or parasitic infections may experience altered absorption or metabolism of TCE, potentially intensifying its health effects. While this area requires further investigation, it highlights the complex interactions between environmental contaminants and human biology.

Current Contamination Patterns

Surveys by the EPA and state environmental agencies have documented TCE presence in drinking water sources serving millions of Americans. In some cases, communities discovered contamination only after decades of exposure had already occurred. These discoveries have revealed systemic gaps in water monitoring and security protocols. Historical contamination often originated from military bases, aerospace facilities, and dry cleaning operations—locations where TCE's industrial use was concentrated.

(EWG, 2023)

Click the image above or this link to check out the interactive map showing areas of TCE contamination in the U.S. 

What makes TCE contamination particularly concerning is its persistence. The chemical can remain in groundwater for decades, and in some cases, centuries. Communities that thought they had resolved contamination issues discovered years later that the solvent continued to leach into drinking water supplies through complex hydrogeological pathways.

The Case for Enhanced Water Security

Given the evidence connecting TCE and similar industrial solvents to serious health outcomes, municipalities face a compelling case for upgrading security measures at water processing plants. Several specific improvements warrant consideration:

Source Water Protection: Municipalities should implement comprehensive mapping of potential contamination sources within their watersheds and aquifer recharge zones. This includes identifying historical industrial sites, military installations, and dry cleaning operations that may continue to pose contamination risks.

Advanced Monitoring Technology: Current water testing protocols, while useful, operate on sampling schedules that may miss intermittent contamination events. Advanced continuous monitoring systems can detect chemical presence in real time, providing early warning of contamination events.

Treatment System Upgrades: While conventional water treatment removes many contaminants, TCE and similar organic solvents may require specialized treatment technologies such as granular activated carbon or air stripping. Many older water systems have not been upgraded with these technologies.

Access Control and Facility Security: Water processing plants represent critical infrastructure that should be subject to robust physical security measures. Unauthorized access to treatment facilities or distribution systems could theoretically allow introduction of contaminants, though such scenarios would represent extreme security breaches.

Chain of Custody Protocols: Municipalities should implement rigorous documentation of all substances introduced into water systems, with multiple verification steps and independent oversight. This creates accountability and reduces any possibility of unauthorized chemical introduction.

Third-Party Oversight: Independent testing of municipal water supplies by state or federal agencies provides an additional layer of verification beyond internal municipal testing.

Addressing Contamination at Its Source

While water system security is important, preventing contamination represents the most effective approach. Stronger regulation of TCE use, accelerated cleanup of historical contamination sites, and restrictions on disposal practices in sensitive groundwater areas would reduce the burden on water treatment systems. Many states have begun implementing stricter groundwater protection standards, but a patchwork of regulations creates inconsistent protection across jurisdictions.

Industrial facilities using solvents should face mandatory testing and reporting requirements, with penalties for contamination that reaches groundwater. Remediation of known contamination sites should proceed on accelerated timelines, particularly in areas where groundwater feeds municipal water supplies.

Public Health Communication

Municipalities with known TCE contamination have often faced criticism for delayed public notification. Transparent communication about water safety risks enables residents to make informed decisions about water consumption and seek additional protection if desired. Public health authorities should provide clear information about contamination levels, health risks, and recommended precautions.

Conclusion

The scientific evidence linking TCE and similar industrial solvents to serious neurological diseases makes water security a pressing public health priority. While the scenario of deliberate contamination represents an extreme concern, the documented accidental contamination of water supplies with TCE demonstrates clear vulnerabilities in current systems. Municipalities that invest in comprehensive source water protection, advanced monitoring, upgraded treatment technology, and rigorous facility oversight are taking responsible steps to protect their citizens from industrial chemical exposure.

Water safety cannot be treated as a solved problem or assumed to be adequately protected by legacy infrastructure and outdated monitoring protocols. Enhanced security measures, while carrying implementation costs, represent a sound investment in public health. As research continues to clarify the health impacts of environmental contaminant exposure, the case for proactive water protection grows stronger.