NERL Research Abstract EPA's National Exposure Research Laboratory GPRA Goal 5 - Safe Waste Management APM 198 Significant Research Findings from the Hazardous Waste Identification Rule Assessment Scientific Problem and The purpose of the Hazardous Waste Identification Rule (HWIR) Assessment is to assimilate and respond to public comments regarding the EPA's 1995 proposal to amend existing regulations for disposal of hazardous wastes under the Resource Conservation and Recovery Act (RCRA). The proposal outlined the new HWIR that was designed to establish constituent-specific exit levels for low-risk solid wastes. Wastes applicable under HWIR were those designated as hazardous because they were listed, or had been mixed with, derived from, or contained the listed wastes. Under the HWIR proposal, waste generators of listed wastes that could meet the new exit level criteria defined by the HWIR methodology would no longer be subject to the hazardous waste management system specified under Subtitle C of RCRA for those wastes. Basically, this established a risk-based "floor" for low-risk hazardous wastes that would encourage pollution prevention, waste minimization, and the development of innovative waste treatment technologies. The purpose of the rule making is to reduce possible over regulation arising from the older "mixture" and "derived-from" rules promulgated earlier. The HWIR methodology represents the manner in which a national- scale assessment of human and ecological risks are to be determined for establishing appropriate contaminant-specific exemption levels for relevant industrial waste streams. The HWIR modeling technology has been developed to automate the risk assessment methodology. The Agency solicited and received comments from the public and from independent peer reviews in response to a Federal Register Notice (65 FR #138 July 18, 2000) that describes the Multi-media, Multi-pathway, Multi-receptor Risk Analysis (3MRA) methodology, the related software technology, and initial representative results of the HWIR risk assessment. This effort is designed to document responses to public Research Approach National Exposure Research Laboratory — October 2001 ------- and peer review comments related to the following components of the 3MRA application for HWIR for which the Office of Research and Development (ORD) was principally responsible: System (including System Software and System Science) Statistics Surface Water Module Atmospheric Module Chemical Properties and related Databases In all, approximately 200 individual comments related to the above components were received. A similar effort, implemented by the Office of Solid Waste (OSW), has resulted in detailed responses to other elements of the overall 3MRA/HWIR methodology and technology (e.g., science modules, and a national database of site conditions). Results and This effort constitutes Annual Performance Measure (APM) 198, which Implications supports the EPA Goal of Safe Waste Management (GPRA Goal 5). The output of this APM, a technical memorandum containing detailed responses to public comments, is being used to organize and prioritize subsequent modifications to the HWIR methodology and technology. Included in this technical memorandum are 1) a background section that summarizes the history of the HWIR, 2) a summary of major comments and responses per component, and 3) appendices containing detailed listings of specific comments and ORD responses. This APM, combined with a similar effort by the Office of Solid Waste, has provided the EPA with a clear vision of the range and importance associated with public comments regarding the technical nature of the evolving HWIR. The most important comments received concerned aspects of the probabilistic methods employed in the HWIR assessment and, in particular, how these methods are intended to represent uncertainty. Other high priority comments included issues related to the complex (and difficult to follow) methodology and related documentation and to mass balance across the multi-media simulations. Issues raised in public comments reflect the state-of-the-art in exposure and risk modeling and, as such, help point the direction to future advancements that will improve the existing HWIR methodology. The technical memorandum represents one of a series of outputs/products developed within a large inter-office collaborative effort between the ORD and the OSW to develop and implement a state-of-the-art, multi-media modeling technology aimed at bridging the Research Collaboration and Publications National Exposure Research Laboratory — October 2001 ------- science of human and ecological exposure and risk with regulations related to the management of hazardous wastes. This collaboration was initiated in 1997 and is anticipated to continue through OSW's final publication of the HWIR (estimated for 2005) and through at least 2008 for various improvements and additional applications of 3MRA for risk assessment and management. Future Research The responses to public comments and additional responses developed by OSW are being used to organize and prioritize future modifications to the HWIR methodology and technology before final implementation of the rule. Upon completion of the modifications, the updated methodology/technology will be used to develop proposed exemption levels for HWIR. The technology developed for HWIR is part of ongoing efforts to minimize redundancies in modeling technologies and establish consistency across Federal Agencies with respect to human and ecological exposure and risk assessment. A Memorandum of Understanding has been signed by the Department of Energy, Department of Defense, Nuclear Regulatory Commission, U.S. Geological Survey, and the U.S. Department of Agriculture with the intent to establish collaborative efforts with respect to the science and software technology related to multi-media modeling. Finally, because of the high level of importance associated with questions of sensitivity and uncertainty with respect to the HWIR assessment (and, in fact, all multi-media assessments) ORD is implementing specific studies to elucidate and quantify the range of uncertainties influencing the modeling results. Contacts for Questions and inquiries can be directed to: Additional Information Gerard Laniak US EPA, Office of Research and Development National Exposure Research Laboratory Athens, GA 30605-2700 Phone: 706/355-8316 E-mail: laniak.gerard@epa.gov National Exposure Research Laboratory — October 2001 ------- |