Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures (External Review Draft)
Notice EPA is announcing a 60-day public comment period and a public listening session for the external review draft document titled, Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures (External Review Draft), as announced in the February 26, 2010 Federal Register Notice.
PAHs are of concern as potential human health hazards, because many PAHs are demonstrated tumorigenic agents in animal bioassays and are positive in tests for genotoxicity or DNA damage. PAHs occur in the environment primarily as complex mixtures generated from the combustion of substances containing carbon and hydrogen, and rarely occur in the environment as isolated entities. The draft Relative Potency Factor approach is not a reassessment of individual PAH carcinogenicity, but rather provides a methodology for estimating cancer risk from exposure to PAH mixtures by summing doses of component PAHs after scaling the doses (with RPFs) relative to the potency of an index PAH (i.e., benzo[a]pyrene). The cancer risk is then estimated using the dose-response curve for the index PAH.
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