Effects of Distance and Depth on Total and Bioaccessible Lead Concentrations in Soils from Two Farmhouses in Beltsville, Maryland

Movement of soil lead (Pb) has been studied, but Pb bioaccessiblity as a function of distance and depth from houses with histories of lead paint use needs to be investigated. This study investigated the effect of distance and depth on total and bioaccessible Pb near two houses with histories of lead paint use. Soil samples were collected at four distances and four depths. Total and bioaccessible Pb were extracted using 1 N ammonia nitrate and 0.4 m glycine, respectively. Bioaccessible Pb ranged from 27 to 886 mg kg−1 and from 187 to 4796 mg kg−1 for houses 1 and 2, respectively. Total and bioaccessible Pb concentrations were greatest at the 0.5 m distance and 2.5 cm depth for both houses. Percentage of total Pb that was bioaccessible at lower horizons was greater than or equal to that of the surface soil. Soil Pb reduction with increasing distance and depth makes it amenable to soil remediation.