A Comparison of Methods Used to Assess Human Health and Ecological Risks from Petroleum Releases. B. R. DeShields, R. Wood, S. Book, D. Griffin, and E. Hawkins, Harding Lawson Associates, 105 Digital Drive, Novato, CA 94949
Petroleum hydrocarbons are usually evaluated for purposes of human health risk assessment in terms of their constituents (benzene, toluene, ethylbenzene, and xylene [BTEX] and polyaromatic hydrocarbons [PAHs]). However, when BTEX and PAHs are not detected but petroleum hydrocarbons are present (i.e., TPH mixtures are detected), it may be necessary to evaluate TPH as a chemical of potential concern. Methods and guidance are currently under development for assessing human health risks for exposures to TPH. However, less information is available for evaluating the effects of TPH on ecological receptors. Available information on evaluating ecological risks associated with TPH exposures for representative aquatic and terrestrial receptors was reviewed and compared to methods and guidance used to evaluate human health risks for TPH exposures. A method for integrating ecological risk assessments into ASTM’s Risk-Based Corrective Action guidance (ASTM E 1739-95) is presented. In addition, comparative "acceptable risk" values for TPH components are presented.