Article

Estimation of Relative Bioavailability of Lead in Soil and Soil-Like Materials Using Young Swine

Veterinary Medical Diagnostic Laboratory, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.
Environmental Health Perspectives (Impact Factor: 7.03). 09/2006; 114(8):1162-71. DOI: 10.1289/ehp.8852
Source: PubMed

ABSTRACT In this article we summarize the results of a series of studies that measured the relative bioavailability (RBA) of lead in a variety of soil and soil-like test materials. Reference material (Pb acetate) or Pb-contaminated soils were administered orally to juvenile swine twice a day for 15 days. Blood samples were collected from each animal at multiple times during the course of the study, and samples of liver, kidney, and bone were collected at sacrifice. All samples were analyzed for Pb. We estimated the RBA of a test material by fitting mathematical models to the dose-response curves for each measurement end point and finding the ratio of doses that gave equal responses. The final RBA for a test material is the simple average of the four end point-specific RBA values. Results from 19 different test materials reveal a wide range of RBA values across different exposure materials, ranging from 6 to 105%. This variability in RBA between different samples highlights the importance of reliable RBA data to help improve risk assessments for Pb in soil. Although the RBA value for a sample depends on the relative amounts of the different chemical and physical forms of Pb present, data are not yet adequate to allow reliable quantitative predictions of RBA from chemical speciation data alone.

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    ABSTRACT: 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 representingdifferent contamination sources from China were analyzed for Pb bioaccessibility using four in vitromethods (UBM, SBRC, IVG, and PBET), Pb-RBA using a mouse blood model, and Pb fractionation usingsequential extraction. Lead bioaccessibility in the gastric phase (GP) and Pb-RBA was generally lower inmining soils (0.46–29% and 7.0–26%) than smelting (19–92% and 31–84%) and farming soils (13–99% and51–61%), 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 thegastric phase. However, Pb bioaccessibility in the intestinal phase (IP) of all assays sharply decreased to0.01–20% possibly due to Pb sorption to solid phase at higher pH. Lead bioaccessibility by UBM-GP assaywas 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 car-bonate fractions. Our study suggested that UBM-GP assay has potential to determine Pb bioaccessibilityin contaminated soils in China.
    Journal of Hazardous Materials 03/2015; 295:55-62. · 4.33 Impact Factor
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    [Show abstract] [Hide abstract]
    ABSTRACT: 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 representingdifferent contamination sources from China were analyzed for Pb bioaccessibility using four in vitromethods (UBM, SBRC, IVG, and PBET), Pb-RBA using a mouse blood model, and Pb fractionation usingsequential extraction. Lead bioaccessibility in the gastric phase (GP) and Pb-RBA was generally lower inmining soils (0.46–29% and 7.0–26%) than smelting (19–92% and 31–84%) and farming soils (13–99% and51–61%), 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 thegastric phase. However, Pb bioaccessibility in the intestinal phase (IP) of all assays sharply decreased to0.01–20% possibly due to Pb sorption to solid phase at higher pH. Lead bioaccessibility by UBM-GP assaywas 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 car-bonate fractions. Our study suggested that UBM-GP assay has potential to determine Pb bioaccessibilityin contaminated soils in China.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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 representingdifferent contamination sources from China were analyzed for Pb bioaccessibility using four in vitromethods (UBM, SBRC, IVG, and PBET), Pb-RBA using a mouse blood model, and Pb fractionation usingsequential extraction. Lead bioaccessibility in the gastric phase (GP) and Pb-RBA was generally lower inmining soils (0.46–29% and 7.0–26%) than smelting (19–92% and 31–84%) and farming soils (13–99% and51–61%), 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 thegastric phase. However, Pb bioaccessibility in the intestinal phase (IP) of all assays sharply decreased to0.01–20% possibly due to Pb sorption to solid phase at higher pH. Lead bioaccessibility by UBM-GP assaywas 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 car-bonate fractions. Our study suggested that UBM-GP assay has potential to determine Pb bioaccessibilityin contaminated soils in China.

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