Legacy sources to new exposures. A preliminary lead risk assessment to children in the Falun mining area

Abstract

BACKGROUND AND AIM: Like many of Sweden’s metropolitan areas, the city of Falun faces a shortage of affordable housing. The city’s proximity to a historic copper mine presents unique challenges for the growing high-density service and industrial area. Concerns about the feasibility and risks associated with building new housing on land contaminated by the legacy of mining and metal industries motivate a new risk assessment using current reference values for lead. The aim of this project is to undertake a preliminary environmental health-based risk assessment on the lead levels surrounding the mining area, based on previous samples (dust, soil, biomarkers). METHODS: We use environmental samples and research done in Falun from 1986 to 1998 to predict blood lead levels (BLL) today by employing the Integrated Exposure Uptake Biokinetic (IEUBK) software. We further compare calculated to measured BLL from 1993 and to current threshold values from Environmental Protection Agency (EPA) and the Scientific Committee on Health and Environmental Risks (SCHER). RESULTS:The average measured BLL for children 4 years is 3.7 µg/dL and 4 years is 2.8 µg/dL. IEUBK BLL estimates are 1.2-1.4 µg/dL and 0.9-1.1 µg/dL, respectively. Both averages are below the 5 µg/dL threshold used by EPA, and higher or equal than the 1.2 µg/dL associated with the 0,5 µg/dL bodyweight/day tolerable daily intake. CONCLUSIONS:Based on measured and calculated BLL, the exposure exceeds currently acceptable safe levels. However, samples were taken before the ban on leaded gasoline in Sweden in 1994, but also around active mining and smelting. Furthermore, the lead from mining operations in Falun has low bioavailability 0.5%-2%. The lead in the respirable fraction is more associated with smelting operations and leaded gasoline, which have not existed for almost 30 years. Together, these factors result in a possible overestimation of the current lead exposure to children in Falun. KEYWORDS: Built environment, Heavy metals, Exposure assessment-biomarkers of exposure, Risk assessment, Children's environmental health