Acquisition and retention of lead by young children.

The concentrations and isotope ratios of lead in blood and urine, on the hands, and in duplicate diet samples were measured for children living in Omaha, Nebraska. One group consisted of 22 children followed from birth to between 1 and 2 years of age and another group was 20 2- to 4-year-old children followed for 1 year, although some in each group were followed for periods between 3 and 4 years. At no time in life was a component of dietary lead identified in blood by isotope ratios, and blood lead appears dominated by lead derived from the hands, which in turn appears derived from the floors. For some homes floor lead appeared to be a mixture of lead from window sills and from the exterior. Only 2 of the children appear to have ingested lead directly from window sills. Several who lived in homes being remodeled were exposed to lead before the age of 2 years. For those who had been briefly exposed during professional remodeling the blood lead fell with a half-life of 10 months but for those who had suffered prolonged exposure during remodeling by parents the apparent half-life was longer, between 20 and 38 months.