title: Cancer risk assessment of polycyclic aromatic hydrocarbon contaminated soils determined using bioassay-derived levels of benzo[a]pyrene equivalents.
abstract: Here we evaluate the excess lifetime cancer risk (ELCR) posed by 10 PAH-contaminated soils using (i) the currently advocated, targeted chemical-specific approach that assumes dose additivity for carcinogenic PAHs and (ii) a bioassay-based approach that employs the in vitro mutagenic activity of the soil fractions to determine levels of benzo[a]pyrene equivalents and, by extension, ELCR. Mutagenic activity results are presented in our companion paper.1 The results show that ELCR values for the PAH-containing fractions, determined using the chemical-specific approach, are generally (i.e., 8 out of 10) greater than those calculated using the bioassay-based approach; most are less than 5-fold greater. Only two chemical-specific ELCR estimates are less than their corresponding bioassay-derived values; differences are less than 10%. The bioassay-based approach, which permits estimation of ELCR without a priori knowledge of mixture composition, proved to be a useful tool to evaluate the chemical-specific approach. The results suggest that ELCR estimates for complex PAH mixtures determined using a targeted, chemical-specific approach are reasonable, albeit conservative. Calculated risk estimates still depend on contentious PEFs and cancer slope factors. Follow-up in vivo mutagenicity assessments will be required to validate the results and their relevance for human health risk assessment of PAH-contaminated soils.
authors.affiliation: Mechanistic Studies Division, Environmental Health Science and Research Bureau, Health Canada , 50 Colombine Driveway, Tunney's Pasture 0803A, Ottawa, Ontario, Canada , K1A 0K9.
authors.forename: Christine L
authors.initials: CL
authors.lastname: Lemieux
authors.forename: Alexandra S
authors.initials: AS
authors.lastname: Long
authors.forename: Iain B
authors.initials: IB
authors.lastname: Lambert
authors.forename: Staffan
authors.initials: S
authors.lastname: Lundstedt
authors.forename: Mats
authors.initials: M
authors.lastname: Tysklind
authors.forename: Paul A
authors.initials: PA
authors.lastname: White
mesh_terms: D000818:Animals; D001681:Biological Assay; D002273:Carcinogens / Q000032:analysis / Q000633:toxicity*; D002460:Cell Line; D006801:Humans; D051379:Mice; D009369:Neoplasms / Q000139:chemically induced*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000633:toxicity*; D018570:Risk Assessment; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity*
chemical_list: D002273:Carcinogens; D011084:Polycyclic Aromatic Hydrocarbons; D012989:Soil Pollutants