title: The bioaccessibility of soil-based mercury as determined by physiological based extraction tests and human biomonitoring in children.
abstract: Environmental contaminants associated with soil particles are generally less bioavailable than contaminants associated with other exposure media where chemicals are often found in more soluble forms. In vitro methods, such as Physiological Based Extraction Tests (PBET), can provide estimates of bioaccessibility for soil-based contaminants. The results of these tests can be used to predict exposure to contaminants from soil ingestion pathways within human health risk assessment (HHRA). In the current investigation, an HHRA was conducted to examine the risks associated with elevated concentrations of mercury in soils in the northern Canadian smelter community of Flin Flon, Manitoba. A PBET was completed for residential soils and indicated mean bioaccessibilities of 1.2% and 3.0% for total mercury using gastric phase and gastric+intestinal phase methodologies, respectively. However, as many regulators only allow for the consideration of in vitro results for lead and arsenic in the HHRA process, in vitro bioaccessibility results for mercury were not utilized in the current HHRA. Based on the need to assume 100% bioaccessibility for inorganic mercury in soil, results from the HHRA indicated the need for further assessment of exposure and risk. A biomonitoring study was undertaken for children between 2 and 15 years of age in the community to examine urinary inorganic mercury concentrations. Overall, 375 children provided valid urine samples for analysis. Approximately 50% of urine samples had concentrations of urinary inorganic mercury below the limit of detection (0.1 μg/L), with an average creatinine adjusted concentration of 0.11 μg/g. Despite high variability in mercury soil concentrations within sub-communities, soil concentrations did not appear to influence urinary mercury concentrations. The results of the current investigation indicate that mercury bioaccessibility in residential soils in the Flin Flon area was likely limited and that HHRA estimates would have been better approximated through inclusion of the in vitro study results.
authors.affiliation: Intrinsik Environmental Sciences Inc., 6605 Hurontario Street, Suite 500, Mississauga, Ontario L5T 0A3, Canada. Electronic address: asafruk@intrinsik.com.
authors.forename: Adam M
authors.initials: AM
authors.lastname: Safruk
authors.affiliation: Intrinsik Health Sciences Inc., 6605 Hurontario Street, Suite 500, Mississauga, Ontario L5T 0A3, Canada.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Berger
authors.affiliation: Goss Gilroy Inc., 150 Metcalfe, Suite 900, Ottawa, Ontario K2P 1P1, Canada.
authors.forename: Blair J
authors.initials: BJ
authors.lastname: Jackson
authors.affiliation: Goss Gilroy Inc., 150 Metcalfe, Suite 900, Ottawa, Ontario K2P 1P1, Canada.
authors.forename: Celine
authors.initials: C
authors.lastname: Pinsent
authors.affiliation: Hudbay Minerals Inc., 25 York Street, Suite 800, Toronto, Ontario M5J 25, Canada.
authors.forename: Alan T
authors.initials: AT
authors.lastname: Hair
authors.affiliation: Intrinsik Environmental Sciences Inc., 6605 Hurontario Street, Suite 500, Mississauga, Ontario L5T 0A3, Canada.
authors.forename: Elliot A
authors.initials: EA
authors.lastname: Sigal
mesh_terms: D002170:Canada; D002648:Child; D004781:Environmental Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D004787:Environmental Pollution / Q000706:statistics & numerical data; D006801:Humans; D008628:Mercury / Q000032:analysis* / Q000378:metabolism; D018570:Risk Assessment; D012987:Soil; D012989:Soil Pollutants / Q000032:analysis* / Q000378:metabolism
chemical_list: D012987:Soil; D012989:Soil Pollutants; D008628:Mercury
keywords: Human health risk assessment; In vitro bioaccessibility; Smelter community; Urinary mercury