Cancer risk assessment of polycyclic aromatic hydrocarbon contaminated soils determined using bioassay-derived levels of benzo[a]pyrene equivalents

Environ Sci Technol. 2015 Feb 3;49(3):1797-805. doi: 10.1021/es504466b. Epub 2015 Jan 20.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Assay
  • Carcinogens / analysis
  • Carcinogens / toxicity*
  • Cell Line
  • Humans
  • Mice
  • Neoplasms / chemically induced*
  • Polycyclic Aromatic Hydrocarbons / analysis
  • Polycyclic Aromatic Hydrocarbons / toxicity*
  • Risk Assessment
  • Soil Pollutants / analysis
  • Soil Pollutants / toxicity*

Substances

  • Carcinogens
  • Polycyclic Aromatic Hydrocarbons
  • Soil Pollutants