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Lead PoisoningLead Poisoning Lead has no known biological function.Lead has no known biological function. There is no proven safe lower limit for lead.There is no proven safe lower limit for lead. Lead PbLead Pb++++, competes with Ca, competes with Ca++++, Fe, Fe++++

It is cheap, useful , easy to mine.It is cheap, useful , easy to mine. Lead is available in air, food, water& soil.Lead is available in air, food, water& soil. Leaded petrol means that all environmental Leaded petrol means that all environmental

dusts are high in lead-contaminating ceiling dusts are high in lead-contaminating ceiling dust, topsoil, etc.dust, topsoil, etc.

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Absorption Absorption of Leadof Lead Lead goes down iron or calcium absorption Lead goes down iron or calcium absorption

pathway in GIT.pathway in GIT. Children absorb lead well if taken orally Children absorb lead well if taken orally

(~50%) Children also have more hand to (~50%) Children also have more hand to mouth activity.mouth activity.

Lead absorption is enhanced if diet is poor in Lead absorption is enhanced if diet is poor in iron or calcium.iron or calcium.

Pica is one of the worst risk factors.Pica is one of the worst risk factors. Lead can be inhaled.Lead can be inhaled. Tetraethyl lead can be absorbed via skin.Tetraethyl lead can be absorbed via skin.

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Absorption of LeadAbsorption of Lead

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Contribution ofContribution ofSourcesSources

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Distribution of Distribution of LeadLead 95% long bones.95% long bones. 4% brain , liver, 4% brain , liver,

kidneys.kidneys. 1% blood.1% blood. Crosses placenta, Crosses placenta,

foetal BBB is openfoetal BBB is open