title: Elemental concentrations and in vitro bioaccessibility in Canadian background soils.
abstract: Elemental concentrations and bioaccessibility were determined in background soils collected in Canada as part of the North American Geochemical Landscapes Project. The concentrations of As, Cr, Cu, Co, Ni and Zn were higher in the C-horizon (parent material) compared to 0-5 cm (surface soil), and this observation along with the regional distribution suggested that most of the variability in concentrations of these elements were governed by the bedrock characteristics. Unlike the above-stated elements, Pb and Cd concentrations were higher in the surface layer reflecting the potential effects of anthropogenic deposition. Elemental bioaccessibility was variable decreasing in the order Cd > Pb > Cu > Zn > Ni > Co > As > Cr for the surface soils. With the exception of As, bioaccessibility was generally higher in the C-horizon soils compared to the 0-5 cm soils. The differences in metal bioaccessibility between the 0-5 cm and the C-horizon and among the provinces may reflect geological processes and speciation. The mean, median or 95th percentile bioaccessibility for As, Cr, Cu, Co, Ni and Pb were all below 100 %, suggesting that the use of site-specific bioaccessibility results for these elements will yield more accurate estimation of the risk associated with oral bioavailability for sites where soil ingestion is the major contributor of human health risk.
authors.affiliation: Royal Roads University, 2005 Sooke Road, Victoria, BC, V9B 5Y2, Canada. matt.dodd@royalroads.ca.
authors.forename: Matt
authors.initials: M
authors.lastname: Dodd
authors.affiliation: Stantec Consulting Ltd., 400-1331 Clyde Ave., Ottawa, ON, K2C 3G4, Canada.
authors.forename: G Mark
authors.initials: GM
authors.lastname: Richardson
authors.affiliation: Wilson Scientific Consulting Inc., 91 West 28th Ave., Vancouver, BC, V5Y 2K7, Canada.
authors.forename: Ross
authors.initials: R
authors.lastname: Wilson
authors.affiliation: Geological Survey of Canada, 601 Booth St, Ottawa, ON, K1A 0E8, Canada.
authors.forename: Andy
authors.initials: A
authors.lastname: Rencz
authors.affiliation: Geological Survey of Canada, 601 Booth St, Ottawa, ON, K1A 0E8, Canada.
authors.forename: Peter
authors.initials: P
authors.lastname: Friske
mesh_terms: D001682:Biological Availability; D002170:Canada; D004602:Elements; D004784:Environmental Monitoring; D006801:Humans; D019216:Metals, Heavy / Q000032:analysis* / Q000493:pharmacokinetics; D012987:Soil / Q000737:chemistry*
chemical_list: D004602:Elements; D019216:Metals, Heavy; D012987:Soil
keywords: Arsenic; Bioaccessibility; Canadian soils; Lead; Metals