Episode 968: Heavy Metals

Aug 4, 2025

Discover the alarming world of heavy metal toxicity, from the gastrointestinal upset caused by acute exposure to the long-term risks of cancer and kidney failure. Learn about the common sources of lead, mercury, arsenic, and cadmium lurking in everyday items. The discussion highlights how older homes and certain fish can pose serious health risks. Treatment options like chelation therapy are also covered, providing insights into managing different types of heavy metal poisoning and their specific antidotes.

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INSIGHT

Heavy Metal Toxicity Effects

Acute heavy metal toxicity primarily causes gastrointestinal upset.
Chronic exposure raises cancer risk, alters cognition, and can impair kidney function.

ADVICE

Lead Exposure Precautions

Use home test kits to check lead in tap water, especially if living in older homes.
Be cautious of old paint and plumbing as common lead exposure sources for children.

INSIGHT

Mercury Exposure Sources

Mercury is less common in thermometers now but is found in some light bulbs and electronics.
Large predatory fish can concentrate mercury, posing a poisoning risk if consumed.

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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

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
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
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
Jannetto PJ, Cowl CT. Elementary Overview of Heavy Metals. Clin Chem. 2023;69(4):336-349. doi:10.1093/clinchem/hvad022
Järup L. Hazards of heavy metal contamination. Br Med Bull. 2003;68:167-182. doi:10.1093/bmb/ldg032
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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