title: Using in vitro bioaccessibility to refine estimates of human exposure to PAHs via incidental soil ingestion.
abstract: PAH bioaccessibility in contaminated soil was determined using the organic physiologically based extraction test with the inclusion of a sorption sink. Silicone cord was incorporated into the assay in order to overcome the limited capacity of the in vitro medium to accommodate desorbable PAHs. Initially, silicone cord sorption efficacy was determined by assessing sorption kinetics using PAH-spiked sand (phenanthrene, pyrene and benzo[a]pyrene; 10-1000mgkg(-1)). Irrespective of PAH and concentration, >95% of the initial PAH mass partitioned into the silicone cord within 12h although rates were lower at higher concentration and with increasing hydrophobicity. When PAH bioaccessibility was assessed in contaminated soil (n=18), contamination source (i.e. pyrogenic versus petrogenic) influenced PAH bioaccessibility. Individual PAH bioaccessibility ranged up to 81.7±2.7% although mean values ranged from 2.1 (acenaphthalene) to 20.8% (benzo[k]fluoranthene) with upper 95% confidence intervals of the means of 4.5 and 28.3% respectively. Although a PAH in vivo-in vitro correlation is yet to be established, bioaccessibility approaches incorporating sorption sinks represent a robust approach for estimating PAH bioavailability as the desorbable fraction may be a conservative measure of the absorbable fraction.
authors.affiliation: Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095, Australia. Electronic address: Albert.Juhasz@unisa.edu.au.
authors.forename: Albert L
authors.initials: AL
authors.lastname: Juhasz
authors.affiliation: Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095, Australia.
authors.forename: Wayne
authors.initials: W
authors.lastname: Tang
authors.affiliation: Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095, Australia.
authors.forename: Euan
authors.initials: E
authors.lastname: Smith
mesh_terms: D000059:Accidents; D001682:Biological Availability; D004435:Eating; D004781:Environmental Exposure / Q000032:analysis*; D006801:Humans; D008954:Models, Biological; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000493:pharmacokinetics; D012989:Soil Pollutants / Q000032:analysis* / Q000493:pharmacokinetics
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D012989:Soil Pollutants
keywords: Bioaccessibility; Human health exposure assessment; Physiologically based extraction test; Polycyclic aromatic hydrocarbons; Sorption sink