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IRIS Bimonthly Public Science Meeting (September 2014)

UPDATE: The September IRIS Bimonthly Public Science Meeting is scheduled for one day on September 3, 2014.  The agenda is posted under the Agenda tab below.  Based on public input, ethylbenzene issue 2 has been broadened and issue 3 has been added.  If you are interested in participating as an opening discussant on these new issues, please send an e-mail to EPA_IRIS@icfi.com or call Susan Blaine (ICF) at 703-225-2471, no later than August 29, 2014.  If the list of opening discussants changes, an updated Agenda will be posted on Sept 2.

At the September meeting, materials related to the following new assessments will be discussed:

EPA has released scoping and problem formulation materials for new IRIS assessments of ethylbenzene and naphthalene for public comment and discussion. The scoping information is based on input from EPA's program and regional offices and is provided for informational purposes.

During problem formulation, the IRIS Program seeks input from the scientific community and the general public as it frames the specific scientific questions for the systematic reviews that it will conduct to develop the assessments. These problem formulation materials are the first to be developed since the National Research Council released its Review of EPA's IRIS Process in May 2014. EPA followed these recommendations in developing the ethylbenzene and naphthalene problem formulations materials. Background information on the chemicals is also provided.

In order to facilitate a scientific discussion, EPA has identified several key science questions on which we are seeking public input. The meeting agenda will be finalized on or about August 20.

Note: The IRIS Program realizes that the materials for this meeting have been posted approximately 40 days in advance. We acknowledge that this is shorter than the approximately two months in advance that has been customary for the literature-search/evidence-table packages for assessments in Step 1 and the public comment drafts for assessments in Step 4. However, the problem formulation materials posted for this meeting are much shorter than our other documents. They do not exceed 25 pages for either assessment, including prefaces and references. We believe this is still a reasonable amount of notice, and ask that our stakeholders join us in preserving the momentum and productivity of the IRIS Program by making this meeting as successful as the one held in June.

IRIS Bimonthly Public Meeting
September 3, 2014

U.S. EPA Conference Center
One Potomac Yard (South Building)
2777 South Crystal Drive
Arlington, Virginia 22202

 

Scoping and Problem Formulation Materials


Ethylbenzene: Paul Reinhart and George Woodall, Assessment Managers

Key science questions:

Science Question 1: Health outcomes. The preliminary literature survey identified several health outcomes for systematic review (see section3.3). Have any potential health outcomes been missed? Are there inter-relationships between some health outcomes that would warrant their being examined together?

Science Question 2 : Toxicokinetics. The assessment will evaluate and perhaps further develop toxicokinetic models for interspecies extrapolation and route extrapolation (see section 3.4). What key features specific to the kinetics of ethylbenzene would increase the utility of a model?

Science Question 3 : Mode-of-action for mouse lung tumors. In January 2014 an EPA workshop discussed key issues related to the human relevance of lung tumors induced in mice by ethylbenzene, naphthalene, or styrene (see section 3.4). Are there newer data or additional perspectives that would be useful in understanding (1) the role of CYP450 enzymes in the metabolism of ethylbenzene, (2) the contribution of ethylbenzene metabolites to the induction of lung tumors in mice, and (3) the respective roles of genotoxicity and of cytotoxicity and regenerative cell proliferation in the induction of lung tumors in mice?

Science Question 4 : Mode-of-action for rat kidney tumors. Hard (2002) concluded that ethylbenzene-induced renal tubule tumors in rats are related to chemically-induced exacerbation of chronic progressive neuropathy; on the other hand, Seely et al (2002) concluded that this association is marginal (see section 3.4 for references). What data would be useful in resolving this issue?

Science Question 5 : Data gaps, new studies, and research in progress. If you are aware of ongoing, original research that will be published after June 2014, we encourage you to contact us so that we can allocate time on the agenda for one investigator from each research group to discuss the design and, if available, the study results. Members of the public will also be encouraged to register to participate in the subsequent discussion.

The public is encouraged to identify any additional issues that they would like to discuss.


Naphthalene: Channa Keshava, Assessment Manager

Key science questions:

Science Question 1: Health outcomes. The preliminary literature survey identified several health outcomes for systematic review (see section3.3). Have any potential health outcomes been missed? Are there inter-relationships between some health outcomes that would warrant their being examined together?

Science Question 2 : Toxicokinetics. The assessment will evaluate and perhaps further develop toxicokinetic models for interspecies extrapolation and route extrapolation (see section 3.4). What key features specific to the kinetics of naphthalene would increase the utility of a model?

Science Question 3 : Mode-of-action for mouse lung tumors. In January 2014 an EPA workshop discussed key issues related to the human relevance of lung tumors induced in mice by ethylbenzene, naphthalene, or styrene (see section 3.4). Are there newer data or additional perspectives that would be useful in understanding (1) the role of CYP450 enzymes in the metabolism of naphthalene, (2) the contribution of naphthalene metabolites to the induction of lung tumors in mice, and (3) the respective roles of genotoxicity and of cytotoxicity and regenerative cell proliferation in the induction of lung tumors in mice?

Science Question 4 : Mode-of-action for rat nasal tumors. Naphthalene has been associated with the induction of nasal cavity tumors in rats (see section 3.4). What data would be useful in developing hypothesized mode(s)-of-action for this tumor?

Science Question 5: Analysis of toxicogenomics data in this assessment. Toxicogenomics data for naphthalene are available and might be informative for evaluating species and sex differences (see section 3.4). We are interested in hearing a variety of ideas on how to analyze these data.

Science Question 6 : Susceptibility factors. Several reviews have discussed deficiency in the enzyme G6-PD as a potential susceptibility factor for the toxic effects of naphthalene. It also has been noted that hematologic effects of naphthalene are more frequently seen in infants (see section 3.4). We are interested in hearing a variety of ideas on how to analyze these data.

Science Question 7 : Data gaps, new studies, and research in progress. If you are aware of ongoing, original research that will be published after June 2014, we encourage you to contact us so that we can allocate time on the agenda for one investigator from each research group to discuss the design and, if available, the study results. Members of the public will also be encouraged to register to participate in the subsequent discussion.

The public is encouraged to identify any additional issues that they would like to discuss.


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