| Lead poisoning of children is a widespread problem in urban areas worldwide. The principal causes of lead poisoning are thought to be consumption of paint fragments, and contaminated soil and dust. Recent tests in Metropolitan Detroit showed lead poisoning of children to be an ongoing problem, although the relative contribution of contaminated urban soil remains to be determined. In this study, the potential contribution to elevated blood lead levels from contaminated urban roadside soil and soils contaminated by smelters and incinerators was studied.;The present investigation involved the collection of surficial soil samples, soil characterization, and analytical determination of soil-lead content in two metropolitan areas, Metropolitan Detroit, Michigan, USA, and Maracaibo, Venezuela. Leaded gasoline is still in use in Venezuela, while it was banned in Detroit in 1986. In addition, other tasks included the sequential extraction analysis of soil samples, to determine the chemical partitioning of Pb in different phases of soil, and isotopic analysis of Detroit soil samples to determine the most prevalent source of lead contamination in the area. An additional step is added to the sequential extraction procedure to further break down the organic phase into humic and fulvic acids.;Both datasets (Detroit and Maracaibo) show similar patterns of lead adsorption, with the soil phases responsible for adsorption of the highest amount of lead in both areas being the organically bound, Fe-oxide occluded and residual fractions.;Bioavailability of soil-lead was studied through analysis of lead uptake by earthworms. It was determined that the best predictor of lead concentration in earthworms is the total amount of lead in the soil, although there was a positive and statistically significant correlation between the amount of lead in the worms and all of the last three fractions of the sequential extraction procedure individually (organically bound fraction, Fe-oxide fraction and residual fraction).;A new technique for the determination of lead concentration in soil was evaluated: Laser Induced Breakdown Spectroscopy (LIBS). All soil samples were analyzed by both Atomic Absorption Spectrophotometry (AAS) and LIBS and the concentration results were compared, yielding a statistically significant correlation between concentration measured with the two techniques, with an r2 of 0.94. |
