Ranking Hazardous-Waste Sites for Remedial Action (1994) / Chapter Skim
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3 CLASSIFICATION OF PRIORITY-SETTING APPROACHES
3 CLASSIFICATION OF PRIORITY-SETTING APPROACHES
Pages 65-84
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From page 65... ...
The approaches differ con siclerably according to the single or multiple objec fives of priority rankings, the types of data measures used and their degree of uncertainty, and methods for treating intangible- but nevertheless instrumentalfactors. Before specific models used in priority setting are reviewer!
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From page 66... ...
Reaclers interested in a cle tailed discussion of these approaches should consult the accompa eying citations. ENVIRONMENTAL EVALUATION l The process of assessing the potential effects of environmental contaminants, sometimes called environmental evaluation, may be cliviclec3 into three principal stages Julien et al., 1992~: iclentifica lion, estimation, and comparison.
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From page 67... ...
Through the process of model development, scientific review, and public com meet, procedures for site ranking and priority setting might evolve to include a broader spectrum of potentially affected elements. For example, the 1990 FIRS revisions, discussed in Chapter 4, added new exposure pathways for human contact with contami nated soils and groundwater to surface water migration, and ex panded ecological components to cover a wider range of sensitive environments in the model.
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From page 68... ...
For example, the hazardous waste site rank ing models developed by EPA and DOD, discussed in Chapters 4 and 5, respectively do not include explicit consideration of socio economic impacts, even though such considerations are critical factors for determining the overall impact of possible remediation decisions. The comparison of impacts inherently involves consid eration of values or preferences that may differ for different indi viduals or stakeholders.
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From page 69... ...
Research on the past, present, and projected site opera tions, relations to the surrounding community, and regulatory involvement provides the necessary unclerstanding of the potential nature, magnitude, and degree of contamination. The information collected in this early phase will play an important role in hazard identification, exposure assessment, and risk characterization.
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From page 70... ...
Hazard Iclend~cadon The identification of potential hazards at a waste site is an itera tive process that examines the types and concentrations of contam inants found at hazardous waste sites. Knowledge of community health concerns, site demographics, and land use provides input to the identification process.
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From page 71... ...
Statistical meth oafs are used to analyze previously collected data on a risk source, either from monitoring programs or from accident records, to esti mate the likelihood of a particular accidental release or hazardous event. Finally, modeling is a formal method employed to estimate key parameters, it requires extensive information about a system's processes, data from monitoring programs, historical event rec ords, or assumptions about probability distributions.
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From page 72... ...
Environmental transport analysis identifies the mechanism by which released contaminants move through environmental media. There are five major transport pathways through environmental media that are typically consiclered in estimating health risk at mosphere, surface soil, groundwater, surface water, ant!
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From page 73... ...
The resulting risk characterization summarizes the estimated human or ecologic impacts, which can be compared to risk management goals. The expressions of risk developed during the risk characterization phase are most useful when they reflect uncertainties encountered in the overall risk analysis process.
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From page 74... ...
By improving mathematical models used to produce risk estimates and expanding risk assessment ciata, uncer tainty in risk analysis can be reduced. To help users understand!
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From page 75... ...
The EIS was a formal tool for balancing economic growth con siderations against the effects of pollution on air, land, and water as well as other external effects. Federal agencies were obligated to analyze the impacts of their projects, to consider alternatives, and to take steps to ameliorate serious adverse impacts (Odell, 1976~.
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From page 76... ...
For example, the Battelle ElA approach for a proposed water pro sect considers categories of information on the physical and chemi cal impacts on the body of water and the ecological, aesthetic, and social effects on the surrounding area (Dee et al., 1973~. Scales and weights are assigned to each of these impacts and, like their equivalents in the EPA, DOD, and DOE models, these scales and weights sacrifice information about some variables and impose a quantitative structure on others to arrive at an overall score.
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From page 77... ...
Like wise, the site ranking models have the potential of making the pro cess of setting priorities available to public review, scrutiny, and comment. The EIA process has gone through numerous revisions.
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From page 78... ...
it is used in HRS and DPM for site scoring. A structure~value approach incorporates in a mathematical framework the major input factors that determine impacts and risk, but it does so in a heuristic manner.
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From page 79... ...
The structured value approach is also used in the comparison stage of an environmental evaluation. In the comparison stage, the estimated effects are combined to obtain an aggregate measure of potential impact due to contaminants at a hazardous waste site.
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From page 80... ...
The output from a site ranking model should thus provide information in adclition to the overall score itself, so that one can understand why a high or low score was obtained. The additional information could include individ ual environmental pathway scores, whether site contaminants pose acute or chronic risks, and how the model's value weights affect the overall score.
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From page 81... ...
DOE's Environmental Restoration Priority System has an explicit and formal multiattribute utility basis combining es timates of human health, environmental, socioeconomic, and regu latory benefits of remediation.
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From page 82... ...
because the activities contribute little, not at all, or negatively. As discussed here, cost benefit and cost effectiveness approaches for environmental evaluation have been adapted from private to public sector use for assisting policy makers to achieve well defined goals when resource constraints require the ranking of alternative courses of action.
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From page 83... ...
Therefore, neither EPA's HRS nor DOD's DPM provides explicit consideration of the costs of remedial actions. They are intended!
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From page 84... ...
BINS DOOMS AWE She measure. Me abuser of Base approa^es to predict future eco nomlc outcomes ~ dlOlcult because resource values Mange.
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