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Bioaccessibility of Arsenic in Mine Tailings from Eastern Canada. Brian Laird M.Sc. Candidate Toxicology Graduate Program University of Saskatchewan International Society of Exposure Analysis Paris, France September 2-6, 2006. Rationale & Purpose.
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Bioaccessibility of Arsenic in Mine Tailings from Eastern Canada Brian Laird M.Sc. Candidate Toxicology Graduate Program University of Saskatchewan International Society of Exposure Analysis Paris, France September 2-6, 2006
Rationale & Purpose • Risk assessors typically assume the bioaccessibility of the ingested compound is at least equal to that used to derive the Toxicological Reference Value. • The accuracy of this practice is unknown. • Sources of variability of arsenic bioaccessibility were examined to resolve uncertainty currently present in risk assessment
Hypotheses Arsenic bioaccessibility in mine tailings depend upon: • Arsenic concentration • Mine tailing particle size • The action of GIT microbes
In Vitro GI Model: The SHIME • Recent research has demonstrated that colon microbes may be involved in the formation of genotoxic arsenic metabolites. • The Simulator the Human Intestinal Microbial Ecosystem (SHIME) incorporates the function of the colon microbial community.
Nova Scotia Mine Tailings • Arsenic bioaccessibility in the small intestine and colon stages of the SHIME were evaluated for: • Two size fractions of mine tailings from 3 residential communities