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Bioaccessibility of Ba, Cu, Pb, and Zn in urban garden and orchard soils

Cai, Meifang, McBride, Murray B., Li, Kaiming
Environmental pollution 2016 v.208 pp. 145-152
barium, bioavailability, children, copper, dust, gardens, gastrointestinal system, horticultural soils, ingestion, lead, orchard soils, orchards, organic matter, particle size, particle size distribution, risk factors, toxicity, urban areas, zinc
Exposure of young children to toxic metals in urban environments is largely due to soil and dust ingestion. Soil particle size distribution and concentrations of toxic metals in different particle sizes are important risk factors in addition to bioaccessibility of these metals in the particles. Analysis of particle size distribution and metals concentrations for 13 soils, 12 sampled from urban gardens and 1 from orchard found that fine particles (<105 μm) comprised from 22 to 66% by weight of the tested soils, with Ba, Cu, Pb and Zn generally at higher concentrations in the finer particles. However, metal bioaccessibility was generally lower in finer particles, a trend most pronounced for Ba and Pb. Gastric was higher than gastrointestinal bioaccessibility for all metals except Cu. The lower bioaccessibility of Pb in urban garden soils compared to orchard soil is attributable to the higher organic matter content of the garden soils.