Heavy Metals (Lead, Mercury, Arsenic)

Exposure Definition

Exposure to toxic heavy metals from environmental and occupational sources. Lead: paint, water pipes, soil, industrial emissions; accumulates in bone. Mercury: fish (methylmercury), dental amalgams, industrial; neurotoxic. Arsenic: contaminated groundwater, rice, industrial; carcinogenic. Heavy metals cause oxidative stress, DNA damage, neurotoxicity, and disruption of enzyme function. Susceptibility varies by genetic variants in detoxification and metal-handling pathways.

Proxies

NameUnitMeasurementData source
Blood leadμg/dLICP-MS or atomic absorptionNHANES
Blood mercuryμg/LCold vapor atomic absorptionNHANES
Urinary arsenicμg/LICP-MS; speciation availableNHANES

Data Sources

Data source: NHANES biomonitoring

Geographic scope: United States

Summary stats: {"geometric_mean_blood_lead_ug_dL":0.82,"p95_blood_mercury_ug_L":5.2}

Biological Systems Affected

neurological

Lead and mercury cause neurodevelopmental and cognitive effects; APOE variants may modulate metal neurotoxicity and Alzheimer's risk

Evidence strength: 0.9

cardiovascular

Lead elevates blood pressure; arsenic causes endothelial dysfunction; metals promote oxidative stress and inflammation; may amplify ACE/hypertension pathway

Evidence strength: 0.85

Sensitive Developmental Windows

prenatal (in utero)

Metals cross placenta; fetal brain highly vulnerable to lead and mercury; neurodevelopmental programming; no threshold for lead neurotoxicity

early childhood (0-5)

Hand-to-mouth behavior; higher absorption; developing brain and kidneys vulnerable; lead exposure causes irreversible IQ loss

GxE Highlights

GeneDiseaseDirectionEvidence type
apoealzheimers-diseaseamplifyliterature
acehypertensionamplifypathway

Tissue-Specific Notes

brain— neurotoxicity
kidney— nephrotoxicity
vascular endothelium— dysfunction

References

  1. 1.Weisskopf MG, et al. (2004). Lead, APOE, and cognitive decline in older adults. Epidemiology. doi:10.1097/01.ede.0000129508.26595.0b
  2. 2.Navas-Acien A, et al. (2008). Lead exposure and hypertension: genetic susceptibility. Environmental Health Perspectives. doi:10.1289/ehp.11292
  3. 3.Grandjean P, Landrigan PJ (2014). Mercury, neurodegenerative disease, and gene-environment interaction. Lancet Neurology. doi:10.1016/S1474-4422(13)70278-3
  4. 4.Moon KA, et al. (2017). Arsenic and cardiovascular disease: mechanisms and genetics. Current Environmental Health Reports. doi:10.1007/s40572-017-0142-1