The effect of soil abatement on blood lead levels in children living near a former smelting and milling operation

Objective. To evaluate the effect of soil abatement on children's blood lead concentrations and on environmental levels of lead and arsenic. Methods. Two cross-sectional surveys were conducted. The first (1989) was of a random sample of 6- to 72-month-old children (n=112). The second (1998) included all 6- to 72-month-old children whose parents agreed to participate in the survey (n=215). From 1993 to 1996, soil abatement was conducted around homes with average soil lead concentration >500 parts per million (ppm). Venipuncture blood samples were taken, interviews were conducted, and samples of house dust, soil, water, and paint were tested for lead and arsenic, using identical protocols in both surveys. The expected decline in blood lead concentrations were calculated for children who lived in houses that were abated, compared with children who lived in houses that were not abated. Results. Lead and arsenic in soil and interior dust in homes that underwent soil abatement declined significantly compared to unabated homes (p<.05). After adjustment for potential confounders, the blood lead concentration in children ages 6 to 72 months who lived in soil-abated housing declined 42.8% faster than children who lived in unabated housing (p=0.14). in children ages 6 to 36 months, the decline was 45.4% faster (p=0.03). The estimated reduction in blood lead for children ages 6 to 36 months was 3.5 mug/dL for every 1,000 ppm reduction in soil lead concentration (95% confidence interval [CI]=2.4 mug/dL, 4.6 mug/dL). Conclusion. Soil abatement was associated with a significant decline in children's blood lead and indoor environmental levels of lead and arsenic.