PERSPECTIVES ON LEAD TOXICITY

Lead toxicity causes hematological, gastrointestinal, and neurological dysfunction in adults and children. Symptoms are usually noted with b lood lead greater than 1.93 mu mol/L. Severe or prolonged exposure may also cause chronic nephropathy, hypertension, and reproductive impair ment. Lead inhibits enzymes; alters cellular calcium metabolism; stimu lates synthesis of binding proteins in kidney, brain, and bone; and sl ows nerve conduction. Less severe exposure to lead, designated by bloo d lead levels of 0.4-0.96 mu mol/L, has been implicated in poor pregna ncy outcome, impaired neurobehavioral development, reduced stature in young children, and higher blood pressure in adults. Biochemical and s ystemic effects of high and low level lead toxicity are described. Dus t, water, and paint chips are still major sources of lead but lead fro m folk remedies, cosmetics, food supplements, food preparation utensil s, and improperly prepared infant formula has caused epidemic and spor adic severe lead toxicity. Screening for pediatric low level lead expo sure requires measurement of blood lead.