title: Bioaccessibility of uranium in soil samples from Port Hope, Ontario, Canada.
abstract: Adequate assessment of human health risk of uranium contamination at hazardous waste sites, which is an important step in determining the cleanup strategy, is based on bioavailability data. Bioavailability of uranium from contaminated soil has not been properly determined yet. Bioaccessibility is an in vitro conservative estimate of bioavailability and is thus frequently used for site-specific risk assessment. Bioaccessibility of uranium was measured in 33 soil samples from the Port Hope area in Ontario, Canada, by the physiologically based extraction test (PBET). Higher bioaccessibility values in the gastric plus intestinal phase, 48.4% ± 16.8%, than in the gastric phase, 20.8% ± 11.7%, are very probably the result of more efficient extraction of uranium from soil by intestinal fluid rich in carbonate ions. The observed variability of measured bioaccessibility values is discussed in light of the results of scanning electron microscope examination of the soil samples. Uranium bioaccessibility values in both gastric (acidic) and gastric plus intestinal (neutral) phases are higher in soil samples with smaller uranium-bearing particles and lower in samples where the uranium-bearing particles are larger. We postulate that the most important reason for variability of measured bioaccessibility values in Port Hope soil samples may be the difference in particle size of uranium-bearing particles.
authors.affiliation: Canadian Nuclear Safety Commission Laboratory, 3484 Limebank Road, Ottawa, Ontario, Canada K1V 1E1. Slobodan.jovanovic@cnsc-ccsn.gc.ca
authors.forename: Slobodan V
authors.initials: SV
authors.lastname: Jovanovic
authors.forename: Pujing
authors.initials: P
authors.lastname: Pan
authors.forename: Larry
authors.initials: L
authors.lastname: Wong
mesh_terms: D001682:Biological Availability; D009864:Ontario; D012990:Soil Pollutants, Radioactive / Q000378:metabolism*; D014501:Uranium / Q000378:metabolism*
chemical_list: D012990:Soil Pollutants, Radioactive; D014501:Uranium