Book Description

Lead poisoning in young children is a concern in many urban areas, even 30 years after the banning of Pb-based paint and leaded gasoline. Soil and dust have been found to be prominent lead exposure pathways for children because young children often inadvertently ingest contaminated soil and dust through exploratory hand-to-mouth activities. In 2010, 16.6% of 6,550 children tested in Toledo, OH had blood lead levels (BLLs) above the CDC lead poisoning reference level of 5 μg/dL. The objectives of this study were 1) to quantify the concentration and distribution of total and bioavailable lead in soils of Toledo, OH; 2) to relate total lead and bioavailable lead in soils to BLLs in children; and 3) to model the relationship between BLLs in children and spatial variables such as housing age and road density. Outreach education served as a means to educate students about the dangers of soil lead as well as the importance of sampling protocols in science. Students in Toledo area schools were instructed on proper USEPA soil sampling guidelines and were asked to collect soil samples from their yards. A subsample of 81 soils was analyzed for total lead and bioavailable lead. Site-specific total lead and bioavailability data were used in the USEPA Integrated Exposure Uptake and Biokinetic (IEUBK) model to predict BLLs for children under 7 years of age. A spatial index model was derived using fuzzy sets, analytical hierarchy process (AHP) and weighted linear combination (WLC) to relate 6 spatial predictor variables to the predicted BLLs. It was found that 8.6% of sampled sites had total lead concentrations above the USEPA action level of 400 mg/kg, but 28.4% of soils samples yielded predicted elevated BLLs, suggesting the action level is set too high. The majority of soil samples had lead bioavailability values above 60%, thus increasing the risk of lead poisoning. The spatial variables influencing risk of lead poisoning from most important to least important were age of housing, road density, percent impervious surfaces, home value, household income and soil type. The data predict that lead poisoning disproportionately affects children from low socioeconomic status families.