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TitleGastrointestinal microbes increase arsenic bioaccessibility of ingested mine tailings using the Simulator of the Human Intestinal Microbial Ecosystem (SHIME)
AuthorLaird, B D; Van de Wiele, T R; Corriveau, M C; Jamieson, H E; Parsons, M B; Verstraete, W; Siciliano, S D
SourceEnvironmental Science & Technology (ES & T) vol. 41, 2007 p. 5542-5547,
Alt SeriesEarth Sciences Sector, Contribution Series 20070109
PublisherAmerican Chemical Society (ACS)
Mediapaper; on-line; digital
File formathtml; pdf
Subjectsenvironmental geology; Health and Safety; Nature and Environment; Science and Technology; Economics and Industry; environmental studies; environmental impacts; mine waste products; tailings; tailings analyses; pollution; pollutants; soils; soil geochemistry; metals; arsenic geochemistry; size fractionation; concentration; health hazards; bioaccessibility; human health; risk assessment; cumulative effects
Illustrationsgraphs; bar graphs
ProgramEnvironment and Health
ProgramMetals in the Environment (MITE)
ProgramNSERC Natural Sciences and Engineering Research Council of Canada
ProgramMetals in the Human Environment Research Network (MITHE-RN)
Released2007 06 30
AbstractIt is widely accepted that the use of total metal concentrations in soil overestimates metal risk from human ingestion of contaminated soils. In vitro simulators have been used to estimate the fraction of arsenic present in soil that is bioaccessible in the human digestive track. These approaches assume that (1) the bioaccessible fraction remains constant across soil total metal concentrations and that (2) intestinal microbiota do not contribute to arsenic release. Here, we evaluate both of these assumptions in two size fractions (bulk and < 38 µm) of mine tailings from the Goldenville, Lower Seal Harbour, and Montague Gold Districts, Nova Scotia. These samples were evaluated using an in vitro gastrointestinal model, the Simulator of the Human Intestinal Ecosystem (SHIME). Arsenic bioaccessibility, which ranged between 2 and 20% in the small intestine and 4 and 70% in the colon, was inversely related to total arsenic concentration in the mine tailings. Additionally, arsenic bioaccessibility was greater in the bulk fraction than in the < 38 µm fraction in the small intestine and colon while colon microbes increased the bioaccessibility of arsenic in mine tailings. These results suggest that using a constant percent arsenic bioaccessibility across all metal concentrations in risk assessment should be revisited.