Blood lead surveys of communities in proximity to lead-containing mill tailings

Abstract

In former mining communities tailings containing up to 2% (20,000 ppm) lead (Pb), frequently as galena (lead sulfide), may be present in large piles near residences, as landfill under homes, or mixed with residential soils. The impact of tailings on blood lead was assessed by comparing blood lead values obtained from residents and environmental lead measured in soils and tailings piles. Data from 13 communities were compiled. Approximately 2995 blood lead measurements were available from persons residing on or near tailings, with the majority of samples from children. Blood lead levels were compared to 1806 controls from nearby communities, national norms, and communities with active smelters. Data comparisons indicated that blood lead values in tailings residents were usually comparable to controls. These data suggest that lead present in mill tailings is not readily bioavailable, even to children who played in dirt or tailings piles. Consequently, the hazard of lead in soils appears to be site-specific and influenced by bioavailability; the bioavailability of galena tailings to humans is low. When health risks of lead soils are predicted, factors affecting the bioavailability of lead present in tailings need to be taken into account.