SPECIALTY TOPICS · GUIDE
Other Environmental Exposures With Credible Research
Plain summary of environmental exposures with strong agency-reviewed research, including lead, arsenic in water, radon and PFAS, and what is and is not known about each.
Content last updated . This page has not been medically reviewed.
Back to Emerging Wellness ScienceQuick answer
Some environmental exposures have decades of human research and clear agency statements. This page covers four: lead, inorganic arsenic in drinking water, radon and PFAS. They differ a great deal in how well the evidence is understood, so each is labeled separately. Labels used: established, mixed, insufficient evidence. The aim is to say what research shows, not to alarm. WHO describes identifying and ending the source of exposure as the response for lead and arsenic; this page does not recommend cleanses, chelation or supplements to remove exposures. See Detox, Cleanse and Chelation Claims.
Urgent safety note
For a suspected poisoning in the US, call Poison Help at 1-800-222-1222 or 911 for an emergency. See Poison Help by Country.Comparison at a glance
| Exposure | Main route | Evidence label | Agency position read |
|---|---|---|---|
| Lead | Dust, paint, water, some products | Established harm | WHO: no known safe level |
| Inorganic arsenic | Contaminated drinking water | Established harm | WHO: confirmed carcinogen |
| Radon | Soil gas entering buildings | Established harm | WHO: leading cause of lung cancer |
| PFAS | Water, food, products | Mixed (many chemicals) | EPA and NIEHS: possible links, difficult to specify |
Lead
WHO says there is no level of lead exposure known to be without harmful effects. [1] Young children are particularly vulnerable and can suffer permanent harm. [1] Lead can contaminate drinking water through plumbing with lead pipes, solders and fittings. [1] WHO's clinical guideline recommends that, for people with blood lead at or above 5 µg/dL, the source be identified and action taken to end exposure. [1] Label: established. Testing and treatment decisions belong with a clinician and public health authorities; see Children & Teens.Arsenic in drinking water
Inorganic arsenic is naturally present at high levels in groundwater in a number of countries, including Argentina, Bangladesh, India, Mexico and the United States. [2] WHO calls inorganic arsenic a confirmed carcinogen and the most significant chemical contaminant in drinking-water globally. [2] Organic arsenic compounds, such as those in seafood, are less harmful to health. [2] WHO says the most important action in affected communities is preventing further exposure through a safe water supply. [2] Label: established.Radon
WHO calls radon one of the leading causes of lung cancer, and says risk rises about 16% per 100 Bq/m3 increase in long-term average concentration. [3] Radon is much more likely to cause lung cancer in people who smoke. [3] Label: established. It can be measured with a small passive detector. [3] More on indoor air is at Indoor Air Quality Health Research.PFAS
PFAS are a large group of synthetic chemicals; NIEHS says nearly 15,000 appear in an EPA database and that PFAS were found in the blood of 97% of Americans in a national survey. [4] EPA says most known exposures are relatively low but some can be high. [5] NIEHS says research to date reveals possible links between certain PFAS and some adverse health outcomes, and the National Toxicology Program concluded PFOA and PFOS suppressed the antibody response and were a hazard to immune function in humans. [4] EPA lists associations with reproductive and developmental effects, some cancers and higher cholesterol, but also says effects are difficult to specify because there are thousands of PFAS and exposures vary. [5] Having PFAS in blood is an exposure measure, not a diagnosis. Label: mixed, varying by chemical.US drinking-water rules. EPA established legally enforceable limits for six PFAS in drinking water in April 2024. [6] On May 18, 2026, EPA announced proposed rules that would uphold the limits for PFOA and PFOS, and another proposal would rescind drinking water regulations for PFHxS, PFNA and HFPO-DA (GenX). [6] Read 2026-10-22; this is changing, so check EPA directly.
Frequently asked questions
Is there a safe level of lead?
WHO says there is no level of exposure known to be without harmful effects. [1]
Is arsenic in seafood the same as in water?
No. WHO says organic arsenic in seafood is less harmful than the inorganic form found in contaminated water. [2]
How do I know if my home has radon?
WHO says radon can be measured with a small passive detector. [3]
Are PFAS in everyone's blood?
NIEHS cites a national survey that found PFAS in the blood of 97% of Americans. [4] Presence in blood does not by itself show illness.
Can a cleanse remove PFAS or lead?
Proper evidence not found in the sources read. See the detox claims guide linked above.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Limits of this evidence
- Blood or urine levels show contact, not harm. See Exposure vs Absorbed Dose.
- Home and mail-order tests vary; see Limits of Consumer Environmental and Toxin Testing.
- Supplements marketed to "detox" any of these are a marketing claim. Proper evidence not found in the sources read for a tested supplement that removes them.
References
- WHO, Lead poisoning fact sheet (10 June 2026). Read 2026-10-22.
- WHO, Arsenic fact sheet (7 December 2022). Read 2026-10-22.
- WHO, Radon and health fact sheet. Read 2026-10-22.
- NIEHS (NIH), Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS). Read 2026-10-22.
- US EPA, Our Current Understanding of the Human Health and Environmental Risks of PFAS. Read 2026-10-22.
- US EPA, Final PFAS National Primary Drinking Water Regulation (page updated 2026). Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.