The primary purpose of the National Advisory committee for Acute Exposure Guideline Levels for Hazardous Substances (NAC/AEGL) is to develop guideline levels for short term exposure to airborne concentrations for approximately 400 to 500 high priority, acutely hazardous substances within the next ten years. The NAC/AEGL Committee seeks to develop the most scientifically credible, acute exposure guideline levels possible within the constraints of data availability, resources and time. The NAC/AEGL Committee is currently comprised of representative of federal, state and local agencies, private industry and other organizations in the private sector that will derive programmatic or operational benefits from the existence of the AEGL values.
"1 The DOE recommends using Protective Action Criteria (PAC) values 2 as airborne concentration limits. PAC values are based on established exposure limit values including Acute Exposure Guideline Level (AEGL, Rusch et al., 2000, 2002), Emergency Response Planning Guideline (ERPG, Rusch, 1993), and Temporary Emergency Exposure Limit (TEEL, Craig et al., 1995, 1999) values. Three different types of PACs exist. "
[Show abstract][Hide abstract] ABSTRACT: Emergency preparedness personnel at U. S. Department of Energy (DOE) facilities use the chemical mixture methodology (CMM) to estimate the potential health impacts to workers and the public from the unintended airborne release of chemical mixtures. The CMM uses a Hazard Index (HI) for each chemical in a mixture to compare a chemical's concentration at a receptor location to an appropriate concentration limit for that chemical. This limit is typically based on Protection Action Criteria (PAC) values developed and published by the DOE. As a first cut, the CMM sums the HIs for all the chemicals in a mixture to conservatively estimate their combined health impact. A cumulative HI>1.0 represents a concentration exceeding the concentration limit and indicates the potential for adverse health effects. Next, Health Code Numbers (HCNs) are used to identify the target organ systems that may be impacted by exposure to each chemical in a mixture. The sum of the HIs for the maximally impacted target organ system is used to provide a refined, though still conservative, estimate of the potential for adverse health effects from exposure to the chemical mixture. This paper explores approaches to enhance the effectiveness of the CMM by using HCN weighting factors. A series of 24 case studies have been defined to evaluate both the existing CMM and three new approaches for improving the CMM. The first approach uses a set of HCN weighting factors that are applied based on the priority ranking of the HCNs for each chemical. The second approach uses weighting factors based on the priority rankings of the HCNs established for a given type of concentration limit. The third approach uses weighting factors that are based on the exposure route used to derive PAC values and a priority ranking of the HCNs (the same ranking as used in the second approach). Initial testing indicates that applying weighting factors increases the effectiveness of the CMM chemical mixtures in general, though care must be taken to avoid introducing non-conservative results. In the near future, additional testing and analysis will be conducted that may lead to the adoption of one of the tested approaches into the CMM.
"pesticide residues, additives). For assessing the risks arising from maritime accidents AEGL (acute exposure guideline level) values give a good orientation (Rusch et al., 2002). Even though regulatory guideline values (OEL, TDI, ADI) can vary between countries they are good tools for risk characterization because they are generally set by an expert panel by a weight of evidence approach and are accepted by many regulatory authorities. "
[Show abstract][Hide abstract] ABSTRACT: Ballast water management systems utilizing noxious chemicals have to be approved according to the Ballast Water Convention by the International Maritime Organization (IMO). The approval procedure requires human health risk assessment. Our objective was to evaluate the existing human health risk assessment process for ballast water management systems. Towards this end, we analyzed the available applications for IMO approval. Since the majority of active substances currently in use are oxidative compounds the corresponding treatment systems generate and release a large number of disinfection by-products. The application dossiers only select a number of by-products for risk assessment. We propose a more comprehensive approach based on the type of ballast water management system, the quality of water treated and the toxicity of compounds discharged into the environment. Subsequent to effects assessment we propose to classify substances according to a hazard evaluation procedure, based on an approach used for maritime transport. We identified a need for better exposure assessment. This requires knowledge of exposure situations. We provide a comprehensive listing of occupational and non-occupational exposure settings and quantification models for exposure assessment.
[Show abstract][Hide abstract] ABSTRACT: The primary aim of the Acute Exposure Guideline Level (AEGL) program is to develop scientifically credible limits for once-in-a-lifetime or rare acute inhalation exposures to high-priority, hazardous chemicals. The program was developed because of the need of communities for information on hazardous chemicals to assist in emergency planning, notification, and response, as well as the training of emergency response personnel. AEGLs are applicable to the general population, including children, the elderly, and other potentially susceptible subpopulations. AEGLs are the airborne concentrations of chemicals above which a person could experience notable discomfort or irritation (AEGL-1); serious, long-lasting health effects (AEGL-2); and life-threatening effects or death (AEGL-3). AEGLs are determined for five exposure periods (10 and 30 min and 1, 4, and 8 h). Physiologically based pharmacokinetic (PBPK) models can be very useful in the interspecies and time scaling often required here. PBPK models are used for the current article to predict AEGLs for trichlorethylene (TCE), based on the time course of TCE in the blood and/or brain of rats and humans. These AEGLs are compared to values obtained by standard time-scaling methods. Comprehensive toxicity assessment documents for each chemical under consideration are prepared by the National Advisory Committee for AEGLs, a panel comprised of representatives of federal, state, and local governmental agencies, as well as industry and private-sector organizations. The documents are developed according to National Research Council (NRC) guidelines and must be reviewed by the NRC Subcommittee on Acute Exposure Guideline Levels before becoming final. AEGLs for 18 chemicals have been published, and it is anticipated that 40 to 50 chemicals will be evaluated annually.
Journal of Toxicology and Environmental Health Part A 04/2004; 67(8-10):621-34. DOI:10.1080/15287390490428017 · 2.35 Impact Factor
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