Threshold
ConditionsHealth DriversAboutMethodology

Threshold is a practitioner-facing reference work for environmental design considerations. It is not medical advice and does not replace licensed clinical care.

A project by Courtney Lebedzinski, founder of Wholesome Houses.

Privacy PolicyTerms of ServiceContact

Heavy Metals

OOccupant Health & Exposure

About This Health Driver

Heavy metals are bioaccumulative toxic metals including lead, mercury, cadmium, and arsenic that enter the indoor environment primarily through water supply, aging plumbing infrastructure, contaminated soil, and certain building materials (lead paint in pre-1978 homes, lead-containing glazes in imported ceramics).

How It Affects Bodies

Heavy metals accumulate in tissue, particularly bone (lead), kidneys (cadmium), and brain (mercury). Lead and mercury are neurotoxic, disrupting myelin formation and neural signaling. Cadmium is nephrotoxic and immunotoxic. Arsenic is a carcinogen and immune disruptor. At chronic low-level residential exposure, the dominant pathway is immune dysregulation and oxidative stress rather than acute toxicity.

Where It Comes From

  • Water supply - lead service lines, lead solder in pre-1986 plumbing, municipal infrastructure
  • Lead paint - pre-1978 homes, exterior deterioration creating contaminated soil
  • Plumbing fixtures - brass fixtures containing lead
  • Contaminated soil - industrial legacy contamination near foundations and garden areas
  • Imported ceramics - lead-containing glazes on decorative and food-contact ceramics

How to Address It

  • Whole-house heavy metal filtration - certified for lead, mercury, cadmium removalPlumbing
  • Point-of-use reverse osmosis - drinking and cooking waterPlumbing
  • Annual water testing - heavy metal panelOperations
  • Lead pipe and fixture replacement - lead-free certified materialsPlumbing
  • Soil testing and remediation - raised beds with clean soil for food productionSite

Conditions That Connect to This Health Driver

Multiple Sclerosis

MS clusters are associated with environmental heavy metal contamination; gene-environment interactio...