Since the estimated numbers of children for each source and category are comparable, they cannot be used to rank the severity of the lead problem by source of exposure. The estimate of 5.6 million children less than 7 years of age potentially exposed to lead at some level from gasoline are derived for the number of children in the 100 largest urban areas in the United States where vehicular traffic could be expected to figure significantly in childhood lead exposure. This estimate takes into consideration the phase-down of lead in gasoline required by EPA regulations. Because the use of lead-soldered food cans has decreased dramatically in recent years, lead in food is a declining source of exposure. Nonetheless, dietary exposure remains sufficient to add measurable amounts to the total Pb-B levels of as many as 1 million U.S. children.
Activities are now under way to bring significant reductions of lead in water.
In addition, lead from other sources that has been deposited in dust and soil is recognized as an important problem. Abatement of secondary environmental lead exposure is closely linked to childhood lead-screening programs. These efforts involve environmental evaluation and abatement of exposure for children with recognized lead toxicity. Early screening and detection of exposure and toxicity have reduced the rates of severe lead poisoning. Such effective screening programs will reduce the toxicity and costs of lead poisoning.