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Health information notice: This page covers potential health effects associated with water contaminants. It's general information, not medical advice. Ask your doctor about risks specific to your health history.

Medical disclaimer: This page provides general information about research findings. It is not medical advice. Talk to your doctor about health risks specific to your situation.

PFAS health research has accelerated over the past 20 years, largely because of a legal settlement in West Virginia. DuPont’s contamination of the Parkersburg water supply led to the C8 Health Project, a study of 69,000 people that collected health data from 2005 to 2013. It’s still one of the most detailed datasets on PFAS exposure and human health outcomes.

The science is clearer on some outcomes than others. Here’s what the evidence actually shows.

Outcomes with Strong Evidence

Kidney cancer. The C8 Health Project found a statistically significant link between high PFOA exposure and kidney cancer. A 2017 meta-analysis in Environmental Health Perspectives pooled data from multiple studies and confirmed the association. The relative risk was elevated, though the absolute incidence remains low.

Testicular cancer. Also identified in the C8 Health Project with a significant association. Barry et al. (2013) reported elevated rates of testicular cancer among men with high serum PFOS and PFOA levels. The EPA’s April 2024 rulemaking cited this evidence.

Thyroid disease. PFAS structurally resemble thyroid hormones and appear to disrupt thyroid function. A 2019 study in Environment International (Ballesteros et al.) found higher PFAS exposure associated with higher TSH levels and increased risk of hypothyroidism.

Elevated cholesterol. One of the most consistently replicated findings. High PFOA exposure is associated with higher total cholesterol and LDL. This has been observed across multiple studies and populations.

Immune suppression in children. The Faroe Islands research by Grandjean et al. (2012) found that children with higher cord blood PFAS concentrations showed weaker antibody responses to diphtheria and tetanus vaccines. A follow-up in 2017 found that halving PFAS exposure roughly doubled vaccine antibody titers.

Outcomes with Moderate Evidence

Pregnancy-induced hypertension and preeclampsia have been linked to PFAS exposure in multiple studies, though effect sizes vary. A 2022 meta-analysis in Environmental Research found modest but consistent associations.

Ulcerative colitis appeared in the C8 Health Project as a “probable link” but has not been as consistently replicated in other populations.

Non-alcoholic fatty liver disease has been observed in some population studies but the causal pathway is not established.

What’s Still Uncertain

Most of the strongest studies look at people with very high PFAS exposures, communities near industrial sites with levels in the hundreds or thousands of parts per trillion. Whether lower-level exposure (typical of most utility water) carries the same risks is genuinely unclear. Dose-response relationships for many outcomes haven’t been fully characterized.

The EPA’s 4 ppt limit reflects a precautionary approach given the evidence for harm at higher levels. It doesn’t mean that 5 ppt is definitely dangerous or that 3 ppt is definitely safe. The agency’s risk models suggest measurable cancer risk exists along a continuum from near zero.

PFAS is also not a single chemical. Research on PFOA and PFOS is much more extensive than research on the hundreds of shorter-chain PFAS compounds now in use. Regulatory attention is focused on the most-studied compounds, not necessarily the most harmful ones.

Reducing Your Exposure

There’s no way to eliminate PFAS exposure completely, they’re in the environment, food supply, and consumer products. But drinking water is a significant and controllable exposure pathway.

A point-of-use reverse osmosis system certified to NSF/ANSI 58 removes 90, 99% of PFOA and PFOS from tap water. That’s the most direct intervention available to most households.

How to Remove PFAS from Drinking Water covers specific product options and what NSF certifications to look for.

Medical disclaimer: WaterAnswer.com provides general information only. Nothing on this page is medical advice. Consult a licensed healthcare provider before making health decisions.

Frequently Asked Questions

What diseases are linked to PFAS exposure?
The strongest evidence links high PFAS exposure to kidney cancer, testicular cancer, thyroid disease, elevated cholesterol, pregnancy-induced hypertension, and suppressed vaccine response in children. Evidence for other outcomes (ulcerative colitis, breast cancer, liver damage) is more limited. Most research comes from populations with very high exposures, contaminated community water supplies near industrial sites.
Is there a safe level of PFAS exposure?
The EPA's current position is that no level of PFOA or PFOS exposure is without some health risk. That's why the MCL was set at 4 ppt, the lowest measurable level. However, health risk exists on a continuum. The EPA's own analysis distinguishes between cancer and non-cancer risks at different exposure levels.
How do you get PFAS out of your body?
Your body eliminates PFAS slowly through urine and feces. Stopping ongoing exposure is the main lever you have. There's no clinically established treatment to accelerate PFAS elimination. Cholestyramine (a bile acid sequestrant) has been studied but results are mixed. Some research suggests dietary fiber may help slightly.
Are children more at risk from PFAS?
Yes, for two reasons. First, children's immune systems are still developing, and PFAS suppresses vaccine-induced antibody response. The 2012 Faroe Islands study (Grandjean et al.) found that children with higher PFAS exposure had lower antibody titers after standard childhood vaccines. Second, children drink more water relative to body weight than adults.
Medical disclaimer: WaterAnswer.com provides general information only. Nothing on this site is medical advice. Talk to a licensed healthcare provider before making decisions about your health.