Episode 968: Heavy Metals

Contributor: Megan Hurley MD
Educational Pearls:

Acute toxicity of heavy metals:

• Gastrointestinal upset is the most common presentation

Chronic toxicity of heavy metals:

• Symptoms depend on the metal ingested
• Increased risk of cancer
• Altered mentation
• Developmental delays (in children)
• Kidney failure

Four heavy metals that are tested for in a general panel and their sources:

• Lead
  • Old paint (homes built before 1977) or some older toys
  • Pipes of older homes or those with corrosive agents
  • May obtain testing kits from home improvement stores to test water supply
• Mercury
  • Previously in thermometers, although much less common now
  • Compact fluorescent lightbulbs, LCD screens, and some batteries
  • Large predatory fish like tuna, swordfish, dolphins, and shark
• Arsenic sources
  • Most commonly found in pesticides
  • Contaminated groundwater (especially private wells)
• Cadmiun sources
  • Most commonly found in tobacco smoke
  • Batteries
  • Metal plating and welding
• Additional heavy metals that require specific testing
  • Chromium, Nickel, & Thallium
  • Thallium is found in rodenticides, pesticides, and fireworks

Management of heavy metal toxicity depends on the intoxicant

• Generally, chelation therapy is used for acute and severe cases
• Arsenic: dimercaprol or DMSA
• Mercury: DMPS (chronic or mild) or DMSA (severe)
• Lead: succimer is first line, followed by dimercaprol or EDTA

References

1. Baker BA, Cassano VA, Murray C; ACOEM Task Force on Arsenic Exposure. Arsenic Exposure, Assessment, Toxicity, Diagnosis, and Management: Guidance for Occupational and Environmental Physicians. J Occup Environ Med. 2018;60(12):e634-e639. doi:10.1097/JOM.0000000000001485
2. Balali-Mood M, Naseri K, Tahergorabi Z, Khazdair MR, Sadeghi M. Toxic Mechanisms of Five Heavy Metals: Mercury, Lead, Chromium, Cadmium, and Arsenic. Front Pharmacol. 2021;12:643972. Published 2021 Apr 13. doi:10.3389/fphar.2021.643972
3. Kinally C, Fuller R, Larsen B, Hu H, Lanphear B. A review of lead exposure source attributional studies. Sci Total Environ. 2025;990:179838. doi:10.1016/j.scitotenv.2025.179838
4. Jannetto PJ, Cowl CT. Elementary Overview of Heavy Metals. Clin Chem. 2023;69(4):336-349. doi:10.1093/clinchem/hvad022
5. Järup L. Hazards of heavy metal contamination. Br Med Bull. 2003;68:167-182. doi:10.1093/bmb/ldg032
6. Zhang H, Reynolds M. Cadmium exposure in living organisms: A short review. Sci Total Environ. 2019;678:761-767. doi:10.1016/j.scitotenv.2019.04.395

Summarized & Edited by Jorge Chalit, OMS4

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