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Risk Assessment as an Aid to the Decision-Making Process

This section discusses the feasibility and desirability of using risk assessment as an aid to the decision-making process in the Department of Energy (DOE) Environmental Remediation Program. It also discusses the appropriate application of risk assessment and the barriers to using it.

FEASIBILITY OF RISK ASSESSMENT

Assessments of risks to humans and the environment for remediation programs are technically feasible. The methods of risk assessment have been used extensively by regulatory agencies such as the Nuclear Regulatory Commission, the Environmental Protection Agency (EPA), and the Food and Drug Administration as well as industry. These applications can be and have been applied to environmental risk assessment as well as human health risk assessment. Numerous treatises on the utility of risk assessment, its limitations, and needs for further methodological advances have been written (e.g., publications of the National Research Council, including Risk Assessment in the Federal Government: Managing



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Building Consensus Through Risk Assessment and Management of the Department of Energy's Environmental Remediation Program 2 Risk Assessment as an Aid to the Decision-Making Process This section discusses the feasibility and desirability of using risk assessment as an aid to the decision-making process in the Department of Energy (DOE) Environmental Remediation Program. It also discusses the appropriate application of risk assessment and the barriers to using it. FEASIBILITY OF RISK ASSESSMENT Assessments of risks to humans and the environment for remediation programs are technically feasible. The methods of risk assessment have been used extensively by regulatory agencies such as the Nuclear Regulatory Commission, the Environmental Protection Agency (EPA), and the Food and Drug Administration as well as industry. These applications can be and have been applied to environmental risk assessment as well as human health risk assessment. Numerous treatises on the utility of risk assessment, its limitations, and needs for further methodological advances have been written (e.g., publications of the National Research Council, including Risk Assessment in the Federal Government: Managing

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Building Consensus Through Risk Assessment and Management of the Department of Energy's Environmental Remediation Program the Process, Improving Risk Communication, Issues in Risk Assessment, and Valuing Health Risks and Benefits for EnvironmentalDecision Making). The utility of risk assessment will increase in the future as the relevant methods continue to evolve and improve and additional data are collected. The scenario approach to risk assessment is well suited to the evaluation of cleanup alternatives in that it allows for the inclusion of different assumptions about important factors that will determine the degree of remediation, its cost, and the risk to workers and the public in performing the remediation. Future land use is one such factor. Indeed, without the inclusion of land-use decisions in the risk assessment process, its utility as an element of the overall decision-making process for remediation is greatly reduced. The analytical process should be iterative. As described below, initial contact with interested parties and observation of the available records will typically lead to a “screening evaluation” of risk. One of the major results of this evaluation will be the identification of the data needed for more complete characterization and analysis, although in some cases the screening might turn up evidence of only de minimis (trivial) risk and therefore allow for concentration of attention elsewhere. Further analysis can be done as additional data become available. This need not and probably will not be the end of the risk assessment process. Serial evaluations provide a mechanism for modifying possible remediation programs as new information on exposure and risk becomes available, exposures change, or standards of acceptable risk change. DESIRABILITY OF RISK ASSESSMENT The methods of risk assessment are desirable components of the overall decision-making process associated with environmental remediation. This overall process, as discussed in Section 3, goes beyond risk assessment or even the process of risk management.

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Building Consensus Through Risk Assessment and Management of the Department of Energy's Environmental Remediation Program Risk assessment is fundamental to a comprehensive risk management program. Risk management, in turn, provides information for policy-makers participating in the overall decision-making process, which also uses other quantitative and nonquantitative information. As discussed in the seminal S. Kaplan and B. J. Garrick paper, “On the Quantitative Defintion of Risk”, risk assessment is necessary to answer three basic questions: What can go wrong? How likely is it? What are the consequences? Current methods of risk assessment involve the quantification of uncertainty in measures of factors that contribute to the risks being assessed. These methods can accommodate many of the inevitable limitations of available data. Risk assessment can estimate the likelihood and magnitude of different types of consequences, including acute and delayed effects, and can take into account different measures of exposure, including effective dose equivalent and dose to specific target organs. Its primary use might be in connection with human health-effect end points, but it can also be used to gauge ecological and other environmental impacts. The benefits of risk assessment are the following: It helps in ranking the importance of contributions to overall risk. It helps to identify risks that are easily reduced or eliminated. It helps to clarify what is known and what is not known about waste sites. It can provide an objective basis for decisions on controlling risks, especially for workers employed in the remediation effort. It can provide important quantitative information as input to decisions for allocating resources to remediate sites. It makes it possible to rank remediation alternatives in terms of risk to workers, the environment, and the public. Perhaps most important, it can provide a process for consensus-building and a forum for the participation of stakeholders in the

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Building Consensus Through Risk Assessment and Management of the Department of Energy's Environmental Remediation Program development of the risk assessment process and the identification of important social values in the selection of factors to be assessed and remediation alternatives to be analyzed. This process will hopefully lead to greater acceptance of the eventual result of that remediation as well as provide insights as to how to reduce the public health impact during and after remediation. RESOURCE ALLOCATION USING RISK ASSESSMENT At several points during the workshop, participants discussed the appropriate roles of risk assessment in allocating financial resources. Two issues arose: (1) use of risk assessment in allocating funds among different DOE facilities, and (2) alternatives to risk assessment to ensure sufficient consideration of nonquantifiable factors. In discussing allocation among different facilities, participants referred to the Interim Report of the Federal Facilities Environmental Restoration Dialogue Committee, also known as the “Keystone report.” This report, a recent accommodation between stakeholders and DOE, establishes a process for setting funding priorities for remediation activities among different facilities in the event that insufficient funds are available. The process, named the “fair share” process, is highly detailed; in general, funding shortfalls are to be shared proportionately among facilities, and if this reduction seems likely to result in conflict with legal obligations, DOE may seek changes in the scope or schedule of cleanup activities within a facility through discussion or negotiation with the regulators. Included among the factors that should be considered in the “implementation of the flexible fair share process” is “risk reduction.” Some workshop participants who also participated in the meetings leading to the Keystone report cautioned this committee against

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Building Consensus Through Risk Assessment and Management of the Department of Energy's Environmental Remediation Program upsetting the political compromise represented by that report. Participants at the workshop pointed out that this recommendation had been reached with great difficulty but had eventually been agreed to by DOE, the Department of Defense (DOD), EPA, and other key stakeholders. These participants cautioned the committee against recommending a process that would conflict with or displace the fair-share process before it has even been tried. They stated that the process of resource allocation envisioned in that report did not preclude the use of risk assessment, but they were concerned that reduction of risks to health and the environment might be focused on to the exclusion of other factors (e.g., cultural values and socioeconomic impacts) and be used to avoid meeting the requirement of agreements negotiated with states. In particular, these participants expressed their unease that, because they are concrete, the numerical results of risk assessments would be given undue weight in decisions that will need to incorporate less quantifiable but nonetheless important factors, such as cultural values and socioeconomic impacts. During DOE's earlier effort to develop a priority-setting model that relied heavily on risk assessment, stakeholders stated that they did not see opportunities for their participation in the application of this model and did not believe that their concerns had been adequately considered in its development. As stated above, the committee believes that risk assessment is essential to the proper evaluation of risks and their management. The committee believes that funding for remediation at DOE facilities should be subject to priority-setting and that one of the essential tools for doing this is risk assessment. Risk assessment provides the information necessary to understand the problem and to manage and reduce risks to public and worker health and the environment. It can also improve the cost-effectiveness of remediation, which should have high priority in such activities as the remediation of DOE facilities. Risk assessment can and should be used to involve stakeholders and provide a mechanism for the

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Building Consensus Through Risk Assessment and Management of the Department of Energy's Environmental Remediation Program consideration of their cultural, socioeconomic, historical, and religious values, in addition to the risks to human health and the environment associated with the contamination of DOE facilities and their remediation. The committee believes that many of these values can be placed in the quantiative framework of risk assessment (e.g., dietary considerations that reflect cultural values or special land use considerations that reflect historical or religious values). Obviously, some values cannot be included in a quantitative fashion and must be considered in the broader risk management process. Implementation of this recommendation by DOE when it performs risk assessments should help to alleviate stakeholders' concerns as to the use of risk assessment. APPROPRIATE APPLICATION OF RISK ASSESSMENT Risk assessment is a scientific process that can be used at all stages of remediation; however, appropriate application of risk assessment is essential for its proper use. Lack of incorporation of concerns about cost, uncertainty, implementation time, model use, data availability, etc. into the planning of risk assessments and the risk characterization that is the result of the risk assessment have led some to question its utility. However, the committee believes that the appropriate application of risk assessment can reduce these concerns. Thus, how to appropriately apply risk assessment is the focus of this portion of the report. Initially, contaminants should be identified, their presence quantified, and their geographic distribution determined. A preliminary or screening evaluation can then be used to determine the need for a full risk assessment before a decision is made on remediation. If a more extensive assessment is warranted, the screening evaluation can point to necessary additional data. After the next level of risk assessment, uncertainties would again be considered

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Building Consensus Through Risk Assessment and Management of the Department of Energy's Environmental Remediation Program and a determination made on whether even more data would be required to produce acceptable results in the analysis. The process might continue for many iterations during remediation (see Section 3). The scope of a risk assessment and the risk assessment itself should be influenced by external or even global considerations, i.e., how the site hazard fits in the larger realm of considerations of the stakeholders. Further, risk assessment should be facility-specific so that appropriate stakeholders can participate effectively and so that exposure factors and incidences of health effects relevant to the facility in question are incorporated. Another important factor in appropriately applying risk assessment is risk characterization. Risk assessment entails extensive descriptive and judgmental characterization of the nature of risks to health and the environment, the weight of the evidence, the reversibility or preventability of the effects, the variation of susceptibility among humans, etc. Thus, risk estimates need to be “characterized ” properly because such estimates convey more than just the quantitative estimate of “the risk.” This is a well-established concept in National Research Council and Office of Science and Technology Policy reports and is important in the application of risk assessment to DOE sites as well. Human-health risk assessment should include realistic estimates of risk for the exposed critical group. The appropriateness of either the individual or the population estimate cannot be fully determined at the outset of the assessment, and the combination of the two measures has the potential for adding insight into the risks involved. The weight given to one or the other measure of risk should be the subject of discussions with stakeholders. In some cases, mortality, other health end points, and other intermediate biological markers should be evaluated. Carcinogenesis is all too often the only health outcome analyzed, but it might not be the only or even the most likely outcome of the hazard being assessed.

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Building Consensus Through Risk Assessment and Management of the Department of Energy's Environmental Remediation Program Other elements of the risk assessment process are required for appropriate application. For example, assumptions about the ultimate use of currently contaminated lands determine the characteristics of future risks, and without such assumptions (scenarios), a risk assessment lacks focus and has greatly diminished utility. Scientific uncertainty about the predictors of risk (i.e., dose-response and exposure assessment), another important part of the risk assessment process, comes from two sources. The first is the natural variability of these predictors in any particular scenario of interest. The second is our lack of knowledge about the basic nature of these variables. It is the second source that has almost invariably produced the largest amount of uncertainty in the evaluation of risk. This lack of understanding and data is the bane of the risk assessment process and limits its utility. The overall processes and results of risk assessment are profoundly influenced by uncertainty. Risk managers (and stakeholders), lacking definitive information for risk assessment, often select a worst-case analysis. That is, they use the highest estimate of risk (the upper bound of the full range of uncertain outcomes) as the assigned or putative risk. If this is done consistently, it can lead to greatly exaggerated risks because of the multiplicative nature of risk assessment. Improving the information used often shrinks the range of uncertainty and sometimes leads to a lowering of the worst-case upper bound. Decreasing the level of uncertainty also increases confidence in and understanding of the results of risk assessment. Another important factor is the scientific independence of the risk assessment process. Ideally, risk assessment is a rational process without bias or influence from any value system. It should be a straightforward evaluation of the health or environmental effects per unit of exposure integrated over the potential exposure—a dispassionate prediction of untoward outcomes. But, establishing the level of “acceptable” risk is a risk management function that is highly value-laden. The ideal is to be able to separate risk

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Building Consensus Through Risk Assessment and Management of the Department of Energy's Environmental Remediation Program assessment from risk management as much as possible. The reality is that uncertainty forces the risk assessor to make decisions and value judgments about what might constitute a “reasonable” upper-bound estimate of exposure, the potential effect of that exposure and the risk due to that exposure. This constitutes a limitation for the process. One cannot make good decisions without a reasonable level of knowledge about the drivers of risk. Thus, it can be argued that scientific uncertainty in the basic mechanisms and prediction of risk causes the invocation of value-based judgment; they are directly related in the risk assessment process, which is harmed when made to function with these potential sources of bias. If the uncertainty is very high, as it often is, a risk assessor might be forced to choose a concomitantly high level of assigned risk. Doing this tends to blur the distinctions between competing risks because the ranges of error overlap to a large degree and differentiating among them is difficult. Thus, uncertainty and the judgments that are forced on the risk assessor as a result of it can potentially limit the usefulness, the objectivity, and ultimately the credibility of the process. Because uncertainty can be thought of as a limiting factor in the risk assessment process, we believe that it should be explicitly measured and expressed. Quantitative probabilistic treatments and their presentations of assigned risk should be used. These methods yield a distribution of possible outcomes with associated probabilities, rather than a point estimate of risk. These types of uncertainty evaluations can further be subjected to sensitivity analysis to determine which variables in risk assessment are producing the most uncertainty about the outcomes and so help to identify the future research or data collection that would do the most to reduce the range of risk estimates and sometimes the upper-bound estimate of assigned risk. Available health-effect and exposure data and models have relatively large uncertainty. If DOE or other stakeholders desire greater utility and less potential bias in the risk assessment process,

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Building Consensus Through Risk Assessment and Management of the Department of Energy's Environmental Remediation Program then greater precision, more research, and more data are required along the following lines: Understanding the relationship between ambient concentrations of contaminants in various environmental media and doses to critical or target organs. Measurement and prospective surveillance of worker and non-worker exposure and health effects. Up-to-date cancer and non-cancer toxicological information on the chemicals and radioactive material of concern. Data on the health effects of mixtures of wastes. Improvements in the health effects measurement (e.g. bio-markers). Predictive modeling of worker and nonworker exposure. Understanding the transport and fate of contaminants in soils and groundwater. Research tools and approaches are available or their development has been reasonably well defined for the above lines of research; however, the financial resources for this research will be substantial. Until the science of exposure assessment and toxicology is advanced through the development and validation of predictive models, the true power of risk assessment will not be realized. This does not mean that the use of risk assessment needs to stop while this research is being conducted. Rather, simultaneous research and risk assessment efforts can provide elucidation for both. Incorporation of these elements into the risk assessment process will lead to the appropriate application of risk assessment and to its becoming an integral part of building consensus for remediation activities. Further, it is important to remember that although risk assessment is an important component or attribute of decision-making, it is not decision analysis. Indeed, well-informed risk management requires expansion of the scope of analysis from risk assessment to

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Building Consensus Through Risk Assessment and Management of the Department of Energy's Environmental Remediation Program a broader decision analysis with the consideration of those attributes of social, religious, historical, political, cultural values, and the costs and benefits of alternative remediation actions under alternative land-use scenarios that cannot be quantified or otherwise properly utilized in the risk assessment process. The quality of risk assessment depends in part on the capability of the analyst; it is vital to the quality of the process that independent external review and public participation occur throughout. As is often the case in its current use, risk assessment provides a “snapshot” in time at a particular phase of understanding of the issues and problems; to be truly instructive and constructive, risk assessment should be updated throughout remediation. REMOVAL OF BARRIERS TO RISK ASSESSMENT Within DOE, all levels and all programs need to establish a culture that is receptive to the adoption of risk-based thinking as a component of decisions on remediation. The various programs within DOE should coordinate their risk assessment needs and guidance to improve the efficiency of the process. A barrier caused by DOE's decentralized approach to managing is that each facility develops its own approach to risk assessment. This has caused a diversity of opinions and methods to be developed and applied at the facility level and numerous communication barriers to arise. To be fully effective in the future, risk assessments must be devised and implemented with a commonality that will avoid this. There will be a tension between the need for facility-specific risk assessment, which can involve stakeholders in a comprehensive fashion (see Section 3 for a more complete treatment of this topic), and the need for general methodological guidelines that permit DOE facilities and stakeholders (which include regulators as well as citizen groups) to benefit from their collective experience.

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Building Consensus Through Risk Assessment and Management of the Department of Energy's Environmental Remediation Program The current regulatory framework is not conducive to the use of risk assessment in the decision-making related to the remediation of DOE facilities. There is little incentive or requirement for the uniform methods and use of risk assessment in the state and federal regulatory process (as opposed to the high-level radioactive-waste disposal program) for the coordination of assessments. Assessments that DOE seeks to use in setting remediation priorities and more generally in risk management have little relation to assessments required by EPA in its CERCLA guidelines for Superfundsite remediation at DOE facilities. Indeed, because some stake-holders (including regulators) fear that DOE will use risk assessment simply to circumvent or cast doubt on current regulations or agreements, they are reluctant to help DOE to develop a tool that could be so used. DOE needs to coordinate with EPA, other federal agencies, state regulatory agencies, and the public to facilitate the use of risk assessment in remediation. In addition, DOE should continue to improve its working relationship with the Agency for Toxic Substances and Disease Registry, so that appropriate population-based exposure and health surveillance information are improved for affected or potentially affected workers and members of the general population. Stakeholders, in addition to DOE managers, need to be assisted in understanding the nature, workings, and limitations of risk assessment if they are to participate effectively in the risk-assessment process. All information on remediation and risk assessment should be presented in an understandable form and in a form that can be used by the participants.