PFAS — The 'Forever Chemicals' in Your Tap Water

In the early 2000s, a lawyer named Rob Bilott began investigating why cattle near a DuPont factory in Parkersburg, West Virginia were dying at alarming rates. The culprit turned out to be PFOA — a chemical used to make Teflon — that had been discharged into the local water supply for decades.

What Bilott uncovered, through years of litigation and discovery, was that DuPont had known about PFOA's toxicity for decades and had continued to contaminate Parkersburg's water supply anyway. The C8 Health Project that followed — one of the largest environmental health studies ever conducted — examined over 69,000 people exposed to PFOA through the drinking water and found probable links to six diseases: kidney cancer, testicular cancer, thyroid disease, ulcerative colitis, high cholesterol, and pregnancy-induced hypertension.

The story became the film Dark Waters. More importantly, it became the foundation for a regulatory response that has only recently arrived.

In April 2024 — more than 70 years after PFOA was first introduced into commerce — the EPA finally set the first-ever enforceable limits for PFAS in drinking water: 4 parts per trillion for PFOA and PFOS. Four parts per trillion. The level at which health effects had been documented was so low that regulators had spent decades arguing it was too impractical to regulate.

PFAS — per- and polyfluoroalkyl substances — is an umbrella term for over 12,000 synthetic compounds built around the carbon-fluorine bond, one of the strongest in chemistry. That bond is why they work so well: they repel water, oil, and heat in ways that make them useful in cookware, food packaging, firefighting foam, waterproof clothing, carpeting, and hundreds of industrial processes.

It's also why they persist. "Forever chemicals" is not marketing language — PFAS do not break down in the environment or in the human body under normal conditions. They accumulate in soil, groundwater, and wildlife food chains. They accumulate in human blood, liver, and kidneys. Once they're in, they're in for years.

The health effects The C8 Health Project and subsequent studies have established associations between PFAS exposure and: • Kidney and testicular cancer • Thyroid disease • Immune suppression — a 2012 JAMA study found that children with higher PFAS exposure had significantly reduced antibody responses to routine vaccinations • Reproductive harm: reduced fertility, pregnancy complications, lower birth weight • High cholesterol • Liver disease

The exposure route Drinking water is the most significant source of PFAS exposure for people in contaminated areas. But dietary sources — food packaging, especially microwave popcorn bags and fast-food wrappers — and consumer products (stain-resistant carpets, waterproof jackets) also contribute to background exposure.

PFAS contamination in US drinking water is widespread — but not evenly distributed. Knowing where the concentration is highest matters for understanding personal risk.

Military installations The highest-concentration contamination in the US clusters around military bases and airports where AFFF (aqueous film-forming foam) — a PFAS-containing firefighting foam — was used for training and accident response for decades. Many military base communities have documented PFAS contamination of local groundwater at levels far above the new EPA MCLs.

Industrial facilities Manufacturing facilities that produce or use PFAS compounds have created local contamination plumes in surrounding groundwater. DuPont's Washington Works plant in Parkersburg remains the most documented, but similar patterns exist around facilities in North Carolina, Minnesota, and elsewhere.

Nationwide reach Analysis by the Environmental Working Group and others suggests PFAS are detectable in drinking water serving over 200 million Americans. Most readings are below the levels documented in Parkersburg or near military bases — but the 2024 EPA MCL of 4 ppt means that a significant fraction of public water systems are now in violation of federal standards, even at background exposure levels.

Private wells Private wells are not subject to Safe Drinking Water Act regulations and are not systematically tested. Residents on well water near PFAS sources may have no idea they're exposed.

The good news on PFAS is that filtration works — unlike some other contaminants, effective removal technology exists and is accessible.

Most effective filtration technologies: • Reverse osmosis (RO): Removes 90%+ of PFAS from water. Under-sink RO systems certified to NSF/ANSI Standard 58 are the gold standard for home use. They also remove other contaminants — nitrates, heavy metals, DBPs. • Activated carbon block filters: High-quality activated carbon (not granular activated carbon, which is less effective) removes PFAS significantly, though not as completely as RO. Certified to NSF/ANSI Standard 53 or 58. • Ion exchange resins: Used by utilities for large-scale treatment; home-scale systems exist but are less common.

What doesn't work: Standard pitcher filters (Brita Classic, etc.) and most refrigerator filters are not certified for PFAS removal. Check NSF certification before assuming a filter is protective.

Check your system PollutionProfile's Water Quality feature connects your address to your utility's PFAS testing history, including data from the new 2024 EPA monitoring requirements. If your system has elevated PFAS readings, the feature guides you through the filtration options most appropriate for your specific contaminants. For people near military bases or industrial facilities, this isn't a precautionary exercise — it's a direct health priority.