Characterizing Cumulative Risk From Multiple Criteria Air Pollutants: U.S. EPA’s Current Approach and Opportunities for Improvement
Neal Fann, U.S. Environmental Protection Agency, Office of Air and Radiation
In this presentation, I will describe the U.S. Environmental Protection Agency’s (USEPA) methods for assessing the cumulative effect of population exposure to multiple criteria pollutants. The first portion of my discussion will focus on the way in which USEPA assesses these impacts in a regulatory context, with an emphasis on the recently promulgated Cross-State Air Pollution Rule. In particular, I will detail the human health benefits assessment, the evaluation of welfare benefits and the Environmental Justice assessment. Next, I will describe an Environmental Justice Assessment performed as part of a multi-pollutant pilot project for Detroit (Fann et al., 2011). In that project, USEPA used a combination of demographic, baseline health and exposure data to identify susceptible and vulnerable populations and then evaluated the ability of alternate air quality management strategies to deliver air quality improvements among these population sub-groups.
Cumulative Risk Assessment at EPA – Assembling the Pieces
Lawrence Martin, Risk Assessment Forum, U.S. EPA Office of the Science Advisor
The EPA Framework for Cumulative Risk Assessment (CRA) was published in 2003. In the intervening years, the EPA CRA Technical Panel has sponsored three workshops, a dozen white papers, and prepared an interim “lessons learned” document. Concurrently, the EPA’s Office of Research and Development and the program offices have developed methods to advance discrete dimensions of CRA. The CRA Technical Panel expects to complete a draft of the CRA Guidelines for review in 2013. Writing teams are being assembled and are integrating the knowledge from across the agency and from the expert authored topical papers. This presentation will provide an overview of the draft outline for the CRA Guidelines, and highlight key issues defining the project. Topics include addressing vulnerable and susceptible populations, integrating chemical and non-chemical stressors, how to organize the boundaries of a CRA, integrating human health and ecological information, and how CRA can be used to inform sustainability analysis.
Integrating Chemical and Non-Chemical Stressors in Cumulative Risk Assessment
Jonathan Levy, Professor, Boston University School of Public Health
Jane E. Clougherty, Assistant Professor, University of Pittsburgh
In a white paper titled “Integrating Chemical and Non-Chemical Stressors in Cumulative Risk Assessment,” we focused on strategies for inclusion of non-chemical stressors in human health cumulative risk assessment. We began by discussing the planning and scoping phase of the analysis, building on previously proposed frameworks to delineate the contexts in which non-chemical stressors should and should not be included in cumulative risk assessments, as well as strategies for their inclusion. We then considered the hazard identification step, as an initial qualitative determination of the stressors under consideration in the analysis. We discussed available databases and metrics that could allow for characterization of exposure to non-chemical stressors, considering theoretical ideal parameters as well as proxy measures or default assumptions that could be used in the absence of detailed population-specific data. For dose-response modeling, we presented strategies that could be used for either epidemiological or toxicological evidence, with a broad-based discussion regarding similarities and differences from the chemical mixtures problem. We briefly addressed risk characterization as a step that synthesizes evidence across outcomes from a stressor-based cumulative risk assessment, or appropriately contextualizes the findings from an effects-based cumulative risk assessment. We concluded by identifying significant data and methodological gaps that could be addressed by targeted research.
EPA Intramural Research on Community-Level Cumulative Risk Assessment, EPA CRA Guidelines and Current Research Challenges
Bradley D. Schultz, National Exposure Research Laboratory, EPA
The EPA is working to advance cumulative risk assessment (CRA) through intramural and extramural research programs, ongoing development of CRA Guidelines, and other activities. The objectives are to improve health and well-being in the United States and reduce health disparities, using high-quality science and fostering economically informed decisions. The goal of this presentation is to describe intramural EPA research efforts and how they complement activities inside and outside EPA as well as the EPA CRA Guidelines under development. CRA in the new EPA research structure will be summarized, as well as a November 2011 workshop on integrating chemical and non-chemical stressors in CRA and plans for a follow-up autumn 2012 workshop. The presentation will assess some accomplishments to date as well as remaining scientific and implementation challenges.
Issues Related to Backward and Forward Translation of Toxicological and Epidemiological Studies of Cumulative Risk Assessment
Deborah A. Cory-Slechta, Professor, Department of Environmental Medicine, University of Rochester School of Medicine
Toxicological studies have the potential to assist in hypotheses and experimental designs of related epidemiological studies, and epidemiological study outcomes can provide information critical to further refinement of animal models. However, several issues currently attenuate the extent to which toxicological and epidemiological studies can inform and advance each other. In the case of “stress” as a component of cumulative risk, there is the acute need to recognize in both toxicological and epidemiological studies that stress can have both positive and negative consequences, leading, for example, to either resilience or further behavioral pathology. Although grounded in the scientific literature that includes underlying mechanisms and pathways, it would be extremely useful for toxicological studies to develop stress protocols that better simulate human and environmental conditions. Both toxicological and epidemiological studies can benefit from better methods for evaluating interaction effects, a particular problem when human sample sizes are limited. Finally, based on toxicological study outcomes, separation of effects by gender in human studies is critical.