[Lead and health]

As far as is known, lead is not required by animals. Lead poisoning is almost always caused by the oral ingestion of too much lead (alimentary contamination). Less than 44 mg lead per kilogram dry weight of feed is considered safe for cattle. Lead intoxication presents in a gastrointestinal form, an encephalic form, a haematological form, and as peripheral neuropathy. Zinc-protoporphyrin (ZPP) and zinc levels in blood should be measured to diagnose lead poisoning. The acceptable range of ZPP is 2.5 to 3.0 micrograms/g Hb(Fe) or less than 150 micrograms/l; more than 250 micrograms/l is too high. Benelux regulations from 1991 give acceptable concentrations for meat, kidneys, liver (between 0.3 and 0.1 mg Pb per kilogram), and milk (0.05 mg Pb per kilogram) destined for human consumption. The treatment for lead poisoning is described.