Lead (Pb)
Definition
Cumulative neurotoxin from chronic occupational exposure (battery recycling, smelter work), leaded paint, contaminated cosmetics (low-grade sindoor, surma, kohl), and adulterated Ayurvedic preparations. Inhibits delta-aminolevulinic acid dehydratase and ferrochelatase, causing microcytic anaemia.
- Toxicity type
- Cumulative neurotoxin
- Common sources
- Battery recycling, leaded paint, kohl, sindoor
- Enzymes inhibited
- ALA dehydratase, ferrochelatase
- Blood effect
- Microcytic anaemia
Common questions
Why does lead cause anaemia?+
Lead blocks enzymes in the haem synthesis pathway, including ALA dehydratase and ferrochelatase, which are needed to build functional haemoglobin. The resulting defective red blood cells are smaller than normal, producing a microcytic anaemia pattern on blood tests.
Why is lead exposure especially concerning in cosmetics and traditional remedies?+
Products like low-grade kohl, surma, sindoor, or some Ayurvedic preparations can contain lead compounds added deliberately for colour or texture, or as contamination, and repeated topical or oral use, especially in children, causes chronic low-level exposure that accumulates over time.
Related terms
- Arsenic (As)
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- Dry Ashing
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- Hydride Generation (HG-AAS)
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- Marsh Test (1836)
- Confirmatory test for arsenic devised by James Marsh after the Bodle case (1832), in which Marsh was unable to convince a jury...
- Mercury (Hg)
- Three toxic forms: elemental (vapour from broken thermometers, dental amalgam), inorganic salts (mercuric chloride, corrosive sublimate), and organic (methylmercury from biomagnification, ethylmercury...
- Reinsch Test
- Classical screen for arsenic, antimony, mercury and bismuth. A clean copper strip is immersed in the acidified sample (concentrated HCl, near-boiling) for...
- Thallium (Tl)
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- Wet Digestion
- Viscera is digested with HNO3 + H2SO4 + HClO4 (or HNO3 + H2O2) at controlled temperature. Closed-vessel microwave-assisted digestion in Teflon bombs...