Mutagenic hazards of complex polycyclic aromatic hydrocarbon mixtures in contaminated soil

Authors

  • Christine L. Lemieux,

    1. Mutagenesis Section, Safe Environments Program, Health Canada, 50 Columbine Drive, Tunney's Pasture 0803A, Ottawa, Ontario K1A 0K9
    2. Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
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  • Iain B. Lambert,

    1. Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
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  • Staffan Lundstedt,

    1. Environmental Chemistry, Department of Chemistry, Umeå; University, SE-901 87 Umea°, Sweden
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  • Mats Tysklind,

    1. Environmental Chemistry, Department of Chemistry, Umeå; University, SE-901 87 Umea°, Sweden
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  • Paul A. White

    Corresponding author
    1. Mutagenesis Section, Safe Environments Program, Health Canada, 50 Columbine Drive, Tunney's Pasture 0803A, Ottawa, Ontario K1A 0K9
    • Mutagenesis Section, Safe Environments Program, Health Canada, 50 Columbine Drive, Tunney's Pasture 0803A, Ottawa, Ontario K1A 0K9
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  • Published on the Web 11/20/2007.

Abstract

The objective of the present study was to evaluate hazard/risk assessment methods for complex environmental mixtures that involve a targeted, priority chemical approach based on the cumulative hazard/risk of known mixture components or analyses of sufficiently similar mixtures. Ten polycyclic aromatic hydrocarbon (PAH)–contaminated soils were separated into nonpolar and semipolar fractions, and both fractions elicited positive responses on the Salmonella reverse mutation assay. Targeted and nontargeted methods of hazard prediction routinely overestimated mutagenic activities for the nonpolar soil fractions, suggesting nonadditive interactions of PAHs in complex mixtures. This suggests that current risk assessment methods for complex mixtures may provide conservative estimates regarding soils contaminated with priority PAHs alone. Significant underestimations of total risk, however, will be obtained if the soils also contain unidentified PAHs as well as polycyclic aromatic compounds and related compounds that contribute to the total mutagenic activity. Furthermore, estimates of excess lifetime cancer risk associated with the nondietary ingestion of the PAH-contaminated soils studied here indicate that a traditional risk assessment model based on identified priority PAHs and an assumption of additivity generally underestimates the risk associated with the nonpolar soil fractions (in comparison to bioassay-derived risk estimates). Additional cancer risk may be associated with the more polar compounds that also are found at these contaminated sites and that rarely are included in the standard risk assessment methodology.

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