Development of a Relative Potency Factor (Rpf) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures (External Review Draft, Suspended)
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Abstract
EPA is conducting a peer review and public comment of the scientific basis supporting the human health hazard and dose-response assessment of polycyclic aromatic hydrocarbon (PAH) mixtures that when finalized will appear on the Integrated Risk Information System (IRIS) database.
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.
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.
Impact/Purpose
The draft Relative Potency Factor approach is not a reassessment of individual PAH carcinogenicity, but rather provides a cancer risk estimate for 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.
Citation
U.S. EPA. Development of a Relative Potency Factor (Rpf) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures (External Review Draft, Suspended). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-08/012A, 2010.
History/Chronology
| Date | Description |
|---|---|
| Oct 2002 | EPA sponsored a Peer Consultation Workshop on Approaches to Polycyclic Aromatic Hydrocarbon (PAH) Health Assessment. |
| Nov 2009 | EPA hosted an interagency science consultation on the draft of the PAH Mixtures Approach. |
| Jan 2010 | SAB releases the names and biosketches of the "Short List Candidates" for the upcoming PAH Mixtures RPF Approach Review Pane. |
| Feb 2010 | EPA released the draft document and charge for a 60-day public review and comment period. Additionally, as per the new IRIS process, all comments received from federal agencies and White House offices on draft IRIS assessments will be made publicly available. Accordingly, interagency comments and the interagency draft of the PAH draft report were also released. |
| Feb 2010 | EPA hosted a public listening session for the external review draft report. |
| Jun 2010 | SAB hosted a Teleconference for SAB PAH Mixtures Review Panel - Orientation and held a follow-up SAB PAH Mixtures Review Panel Meeting to discuss the report later in the month. [Federal Register May 18, 2010] |
| Sep 2010 | SAB hosted the PAH Mixtures Review Panel Teleconference for the discussion of the draft report. [Federal Register Sep 8, 2010] |
| Dec 2010 | SAB hosted a Quality Review of an SAB panel draft report reviewing EPA's IRIS Assessment for Polyaromatic Hydrocarbons. [Federal Register Nov 24, 2010] |
| Mar 2011 | SAB released the final report, SAB Review of EPA's "Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures (February 2010 Draft)". (PDF, 47 pp., 696,671 bytes), EPA-SAB-11-004 |
| Apr 2019 | EPA suspended the assessment in fiscal year 2019. It may be restarted as Agency priorities change. |
This download(s) is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy.
- Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures: In Support of Summary Information on the Integrated Risk Information System (IRIS) (PDF) (622 pp, 7 MB, about PDF)
- Charge to External Reviewers (PDF) (5 pp, 80 KB, about PDF)
- SAB Project Page for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures Review Panel
- SAB Review of EPA's
Related Link(s)
- Draft (9/08/10) SAB Review of EPA's "Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures"
- Peer Consultation Workshop On Approaches To Polycyclic Aromatic Hydrocarbon (PAH) Health Assessment
- IRIS Program Outlook April 2019-Suspended/Discontinued Assessment