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Lead bioaccessibility in 12 contaminated soils from China: Correlation to lead relative bioavailability and lead in different fractions
- Li, Jie, Li, Kan, Cave, Mark, Li, Hong-Bo, Ma, Lena Q.
- Journal of hazardous materials 2015 v.295 pp. 55-62
- bioavailability, blood, farming systems, fractionation, in vitro studies, lead, mice, mining, models, pH, polluted soils, sorption, China
- This study investigated the relationship between Pb relative bioavailability (RBA) and bioaccessibility, and their relationships with Pb in different pools in soils. Twelve Pb-contaminated soils representing different contamination sources from China were analyzed for Pb bioaccessibility using four in vitro methods (UBM, SBRC, IVG, and PBET), Pb-RBA using a mouse blood model, and Pb fractionation using sequential extraction. Lead bioaccessibility in the gastric phase (GP) and Pb-RBA was generally lower in mining soils (0.46–29% and 7.0–26%) than smelting (19–92% and 31–84%) and farming soils (13–99% and 51–61%), with more Pb in the residual fraction in mining soils. Lead bioaccessibility varied with assays, with SBRC (3.0–99%) producing significantly higher bioaccessible Pb than other assays (0.46–84%) in the gastric phase. However, Pb bioaccessibility in the intestinal phase (IP) of all assays sharply decreased to 0.01–20% possibly due to Pb sorption to solid phase at higher pH. Lead bioaccessibility by UBM-GP assay was best correlated with Pb-RBA (r2=0.67), followed by IVG–GP (r2=0.55). Among different Pb fractions, strong correlation was found between Pb bioaccessibility/Pb-RBA and the sum of exchangeable and carbonate fractions. Our study suggested that UBM-GP assay has potential to determine Pb bioaccessibility in contaminated soils in China.