Midvale Community Lead Study

Abstract

The primary objective of this study was to ascertain whether children living in close proximity to mill tailings and a former lead smelter site were currently exhibiting elevated blood lead (PbB) concentrations. To address this issue, the mean PbB for community children and the relationship between PbB and the proximity of the child's residence to the site was estimated. A secondary objective was to identify and quantify accessible lead (Pb) and arsenic (As) in the environment (e.g. Pb in soil, dust, paint and water or As in soil and dust). A third objective was to test for association between specific sources of environmental Pb and PbB and to estimate the relative contribution of these proximate sources of lead to the children's PbB. The data analytic methods allowed estimation of both direct and indirect impact of environmentally accessible Pb. The average PbB level of all children screened in Midvale was 5.2 μg dL⁻¹. Three percent exceeded 15 μg dL⁻¹; 12.7% exceeded 10 μg dL⁻¹. Pb-based house paint and Pb contaminated soil were identified as principal contributors to PbB. PbB was found to increase 1.25 μg dL⁻¹ per 1,000 ppm increase in lead in soil. Proximity of residence to the mill and smelter site was found to be a strong predictor of Pb in soil, and therefore indirectly related to increases in PbB.