[Lead exposure and its effects on child health].

Childhood lead poisoning is a man-made disease whose magnitude has not yet been measured in Chile. In the U.S.A. it has been estimated that 4 percent of children have elevated blood lead levels and that among poor black children, this rate is as high as 18 percent. The main sources of symptomatic lead poisoning are lead-based paint used in interior and exterior house surfaces, airborne lead from leaded gasoline and industrial emissions. Lead can be transferred from any source to soil and dust. Other sources of lead are contaminated food and water, occupational sources, and lead glazed pottery. Neurological symptoms (hyperactivity, distractibility, lower intellectual development), psychological difficulties (behavioral deficits), hematologic abnormalities (reduction in the biosynthesis of heme, anemia), and metabolic changes (reduction in concentration of 1-25 dihydroxy vitamin D and in the metabolism of erythrocyte pyrimidine) have been shown to occur in lead poisoning. Recent data suggests that prenatal exposure to lead my be related to minor congenital abnormalities, tumors of the kidney, and growth abnormalities.