Rainwater everywhere on the planet is unsafe to drink due to chemicals (2022)

Original Article ↗ Hacker News Discussion ↗

Research suggesting that rainwater worldwide now contains unsafe levels of PFAS “forever chemicals” prompts debate over how serious the health risks are, given links to hormone disruption, reduced vaccine efficacy, and cancer. Commenters note that regulatory safety thresholds have tightened dramatically even as PFAS levels in humans have fallen, partly due to treated tap water and improved filtration technologies like activated carbon and reverse osmosis. The exchange broadens into questions about risk tradeoffs, regulatory responsibility, environmental contamination from industry, and how much individuals can realistically do to protect themselves in a world saturated with persistent pollutants.

Health impacts and what “unsafe” means

  • “Unsafe” is discussed as chronic, not acute: PFAS are linked in the thread to cancers, hormone disruption, reduced vaccine efficacy in children, and fertility issues.
  • EPA guideline levels have been repeatedly lowered (down to single‑digit parts per trillion for some PFAS), not because levels rose, but because newer toxicology suggests prior limits were too high.
  • Some argue PFAS represent “huge” self‑inflicted harm; others think human PFAS levels are now declining and the main damage may already be done.

Rainwater vs. treated water and filtration

  • Several comments stress that most people don’t drink raw rainwater; municipal supplies are from groundwater, lakes, rivers, or reservoirs and are treated.
  • Others note many rural areas and off‑grid households do rely on rainwater, which is already biologically risky (bacteria, parasites) even before PFAS.
  • Technologies mentioned as effective for PFAS removal: activated carbon, ion‑exchange resins, and especially reverse osmosis.
  • Debate over scale: home RO/charcoal systems are common in rich regions but many municipal plants lack PFAS treatment due to cost; “industrial‑scale” deployment is uneven.
  • Not all consumer filters fully remove PFAS; RO generally performs best, but some PFAS remain (links to EPA and academic sources in thread).

Exposure, dose, and vulnerable groups

  • Discussion about weight‑based risk: smaller bodies (children, small animals) generally get higher exposure per kg even if they drink/eat less in absolute terms.
  • Commenters dispute how much children drink relative to adults, but agree physiology and activity make them more vulnerable.

Risk comparison and priorities

  • One camp argues PFAS harms are real but small relative to dominant risks like poverty, mental health, drug overdoses, car accidents, diet, and inactivity.
  • Others counter that such reasoning dangerously downplays systemic, planetary‑scale pollution that affects future generations and ecosystems.
  • There is debate over declining testosterone and fertility: some attribute it mainly to pollution/endocrine disruptors, others to obesity, sedentary lifestyles, and social changes; evidence is presented on both sides and causation is labeled unclear.

Environmental spread and “forever chemicals”

  • PFAS are described as near‑permanent, global contaminants found in rain, soils, groundwater, wildlife, and even backyard eggs in the Netherlands; source pathways (rain vs. feed vs. soil) remain unclear in that case.
  • Comments compare PFAS with microplastics and climate change as overlapping symptoms of a broader unsustainable system.
  • A linked study/method to chemically destroy PFAS is mentioned as a hopeful research direction, but only at the lab stage.

Product‑specific exposures

  • Cited consumer sources: non‑stick cookware (Teflon/PTFE), dental floss (especially certain “gliding” brands), some processed foods and grain treatments (e.g., chlormequat on oats), and nitrites in meats.
  • Multiple clarifications:
    • PTFE itself is very inert; historical toxicity issues arose mainly from manufacturing surfactants like PFOA/PFOS and from overheating fumes.
    • Some floss studies used data from the PFOA era; newer PTFE made with different processes may have lower residual PFAS, but long‑term safety is still debated.
    • Regulatory assessments on pesticides like chlormequat say dietary risks are within limits, but several commenters remain uneasy.

Standards, progress, and regulation

  • One line of argument: our standards have tightened dramatically; by historical benchmarks (child mortality, infectious disease, famine) we’re far better off, and incremental chemical risks should be weighed against those gains.
  • The opposing view: that narrative masks serious “bad tradeoffs”; modern prosperity came with massive, poorly understood environmental externalities that could produce large future harms.
  • Several comments criticize “reactive regulation”: chemicals are widely deployed without strong pre‑market safety demonstration, then banned or restricted only after harm emerges.
  • Some express alarm fatigue and a sense that the public cannot track every hazard; others respond that personal exhaustion doesn’t negate real risks and that better institutions (precautionary regulation, enforcement) are needed so individuals don’t have to micromanage exposures.