Most alternatives assessments (AAs) published to date are largely hazard-based rankings, thereby ignoring potential differences in human and/or ecosystem exposures; as such, they may not represent a fully informed consideration of the advantages and disadvantages of possible alternatives. Building on the 2014 US National Academy of Sciences recommendations to improve AA decisions by including comparative exposure assessment into AAs, the Health and Environmental Sciences Institute's (HESI) Sustainable Chemical Alternatives Technical Committee, which comprises scientists from academia, industry, government, and nonprofit organizations, developed a qualitative comparative exposure approach. Conducting such a comparison can screen for alternatives that are expected to have a higher or different routes of human or environmental exposure potential, which together with consideration of the hazard assessment, could trigger a higher tiered, more quantitative exposure assessment on the alternatives being considered, minimizing the likelihood of regrettable substitution. This article outlines an approach for including chemical ingredient- and product-related exposure information in a qualitative comparison, including ingredient and product-related parameters. A classification approach was developed for ingredient and product parameters to support comparisons between alternatives as well as a methodology to address exposure parameter relevance and data quality. The ingredient parameters include a range of physicochemical properties that can impact routes and magnitude of exposure, whereas the product parameters include aspects such as product-specific exposure pathways, use information, accessibility, and disposal. Two case studies are used to demonstrate the application of the methodology. Key learnings and future research needs are summarized. Integr Environ Assess Manag 2018;00:000-000. © 2018 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
The ILSI Health and Environmental Sciences Institute (HESI) Risk Assessment in the Twenty-first Century (RISK21) project was initiated to address and catalyze improvements in human health risk assessment. RISK21 is a problem formulation-based conceptual roadmap and risk matrix visualization tool, facilitating transparent evaluation of both hazard and exposure components. The RISK21 roadmap is exposure-driven, that is, exposure is used as the second step (after problem formulation) to define and focus the assessment. This paper describes the exposure tiers of the RISK21 matrix and the approaches to adapt readily available information to more quickly inform exposure at a screening level. In particular, exposure look-up tables were developed from available exposure tools (European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) Targeted Risk Assessment (TRA) for worker exposure, ECETOC TRA, European Solvents Industry Group (ESIG) Generic Exposure Scenario (GES) Risk and Exposure Tool (EGRET) for consumer exposure, and USEtox® for indirect exposure to humans via the environment) and were tested in a hypothetical mosquito bed netting case study. A detailed WHO risk assessment for a similar mosquito net use served as a benchmark for the performance of the RISK21 approach. The case study demonstrated that the screening methodologies provided suitable conservative exposure estimates for risk assessment. The results of this effort showed that the RISK21 approach is useful for defining future assessment efforts, focusing assessment activities and visualizing results.
The environmental characterization of building interiors and other surfaces has generally been performed with wipe-sampling because it is a non-destructive technique. There is no consensus, however, as to the interpretation of the results of wipe-sampling. Specifically, there is not a standardized method to determine if chemicals found at sampled levels pose a threat to human health. A methodology was developed, based on acceptable health risk levels, to derive screening levels for evaluating wipe-sampling results pertaining to industrial scenarios. The methodology was based on the United States Environmental Protection Agency (USEPA) Region IX Preliminary Remediation Goal (PRG) approach; a multi-exposure methodology commonly used for evaluating soil concentrations. PRGs are the USEPA determined health based goals for soil preliminary remediation efforts. Probabilistic techniques were used to conduct a sensitivity analysis of the methodology to determine which variables drive the ultimate screening levels. Discrete values were then selected based on standard industrial scenarios common to the US Army. The wipe surface screening levels reported are for use as preliminary guidelines which help to determine whether further sampling or cleanup are necessary. The levels are not meant as cleanup or compliance criteria. ᮊ
Within hours after the terrorist attack on the Pentagon on September 11, 2001, an extensive sampling effort was initiated within the building to include surface wipe sampling for select coplanar polychlorinated biphenyls (PCBs), congeners of polychlorinated dibenzo(p)dioxins and dibenzofurans (dioxins/furans) and lead. A risk-based screening level method was utilized to determine the necessity of additional sampling and to assess the potential for emergency response crews, remediation crews, and returning Pentagon workers to have adverse health impact from exposure to the PCBs. dioxins/furans, and lead on nonporous surfaces. The screening level method included all exposure pathways: dermal absorption, incidental ingestion, and inhalation. Various U.S. Environmental Protection Agency (USEPA) guidance documents provided the basis for the method. The underlying assumptions were that the PCBs, dioxins/furans, and lead were contained in the dust or soot layer found on nonporous surfaces, that sampling results were representative of the surfaces from which they were taken, and that the analytical methods employed were able to detect 100% of these substances. A few of the limitations associated with this method included the lack of toxicity values for dermal absorption and the lack of accurate, discrete dermal-exposure values. Evaluation results indicated that additional sampling was not necessary and that concentrations of PCBs, dioxins/furans, and lead on nonporous surfaces were below levels expected to cause adverse health impacts to emergency response crews, remediation crews, and returning Pentagon workers.
In May 1993, Administrative Browner of the U.S. Environmental Protection Agency (USEPA) announced that an indirect exposure health risk assessment was required for all hazardous waste combustion facilities seeking a Resource Conservation and Recovery Act permit. These types of risk assessments evaluate the health and environmental effects from inhalation of emissions (direct exposure) and from contact with environmental media and consumption of food products impacted by the emissions (indirect exposure). Completion of an indirect exposure risk assessment is often complicated by the various methodologies available for generating results and by the requirements of the regulating community. To minimize this complexity and to maximize consistency between risk assessments, the USEPA developed a number of detailed guidance documents. Site-specific conditions and toxicological data gaps, however, continue to present challenges not addressed by these guidance documents. This paper presents some of the specific challenges encountered by the U.S. Army Center for Health Promotion and Preventive Medicine when performing indirect exposure health risk assessments for several demilitarization combustion facilities.
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