Science, risk, and risk assessment and their role(s) supporting environmental risk management.

• Author: Hetes, Robert G.
• Position: Symposium

1. QUALITY DECISIONS NEEDED TO MEET EPA's MISSION OF ENVIRONMENTAL PROTECTION II. ROLE OF SCIENCE III. RISK ASSESSMENT AS A KEY SOURCE OF SCIENTIFIC INFORMATION A. What is Risk? B. What is Environmental Risk? C. The Need for Risk Assessment D. How to Make Risk Assessment Tractable and Feasible? E. Judgment, Normative Values, and Policy Choices are Unavoidable F. Statutory Influences in Risk Assessment G. Limits of Risk Assessment IV. ENSURING QUALITY SCIENCE TO SUPPORT EPA DECISIONS A. Action Development Process (ADP) B. General Assessment Factors C. Peer Review V. HOW CAN IT GO WRONG? VI. WHAT CAN THE EPA Do TO MAINTAIN AND IMPROVE THE ROLE OF SCIENCE? I. QUALITY DECISIONS NEEDED TO MEET EPA'S MISSION OF ENVIRONMENTAL PROTECTION

   The mission of the U.S. Environmental Protection Agency (EPA) is to protect human health and to safeguard the natural environment--air, water, and land--upon which life depends. EPA fulfills this mission by, among other things, developing and enforcing regulations that implement environmental laws enacted by Congress. Inferred is the fact that successful environmental problem-solving must encompass not only "what must be done" (setting a standard or risk management objective), but equally "how it shall be accomplished" (implementation and enforcement). Determining environmental standards, policies, guidelines, regulations, and actions requires making decisions considering this full spectrum. The quality of any decision and resulting action "determines how well environmental programs actually work and the extent to which they achieve health and environmental goals." (1) There are numerous factors which impact the quality and success of any decision or action, and many of these are competing or contradictory forces, such as:

   Legally defensible Clear and concise Comprehensive Simple Flexible Easy to implement Sound analysis Timely and inexpensive The quality and acceptability of any decision is one that effectively balances these factors.

   As described in Risk Assessment Principles and Practices.

   Determining environmental standards, policies, guidelines, regulations, and actions requires making decisions which are often contentious. Setting an environmental standard that is too lax may threaten public health or the environment, while a standard that is unnecessarily stringent may impose a significant marginal economic cost for small marginal gain. Environmental decisions are often time-sensitive, for example when public health is known or suspected to be at risk. The decisions must frequently be made with incomplete or imperfect information and many times under the additional pressure of heightened public scrutiny and concern. And, once made, the decisions are often challenged in court and subject to high levels of public and scientific scrutiny. (2) As a result, such contentious decisions must be based on the current state of knowledge certainty is not required, and appropriate means must be used. Rational support for answers to key questions and an estimate of confidence in the decision must be provided.

   There are often conflicting interests bearing on environmental decisions, and as a result, it is well recognized that it is important (and in some cases even mandated) to consider a broad range of factors when making decisions about risk management including:

   * Risk--nature, magnitude, severity, and likelihood of adverse outcomes/effects

   * Economic factors--costs and benefits of risks and risk mitigation alternatives

   * Laws and legal decisions--framework that prohibits or requires some actions

   * Social factors--attributes of individuals or populations that may affect their susceptibility to risks from a particular stressor

   * Technological factors--feasibility, impact, and range of risk management options

2. ROLE OF SCIENCE

   EPA's credibility depends on the science and analysis underlying its decisions. Ensuring that its regulations have a sound analytical foundation reduces controversy and, to some extent, court challenges. It also increases the likelihood of compliance by the regulated community, which is key to achieving real environmental improvement (3) and public confidence.

   As noted above, science is one factor of many which contribute to a decision. In reality, most decisions are based on a balance of factors, and in some cases may even be influenced or determined solely by factors other than science, such as political or economic considerations. (4) Allowing decisions to be influenced or directed by factors other than science is, of course, legitimate. However, there is a tendency for decision makers to look to science to support or justify their positions ("the science made me do it"). (5) Science is often viewed as objective, value-neutral, and concrete, and many feel that if science can support a decision, it will be non-controversial and acceptable to the broadest range of stakeholders. Highlighting the fact that a decision was based on factors other than science illuminates the underlying values supporting the decision. As a result, this may provide a motivation to influence or undermine the science to provide a science-based rationale for the decision. (6)

   The distinction between science-informed decisions and science-based decisions is critical. Rarely is there sufficient scientific certainty which unequivocally points to or supports a specific decision or action. Quality and defensible decisions are those which are rational, where science is used to inform, and where the limits of science are made clear. Decisions presented as science-based are often supported by rationale alone and are subject to criticism and challenge. To maintain the quality of environmental decisions, the EPA must ensure a science-informed focus that relies on high quality scientific information. The rest of this Article will provide an overview of how EPA approaches this.

3. RISK ASSESSMENT AS A KEY SOURCE OF SCIENTIFIC INFORMATION

   Risk assessment is a key source of scientific information for making good, sound decisions about managing risks to human health and the environment.

   EPA conducts risk assessment to provide the best possible scientific characterization of risks based on a rigorous analysis of available information and knowledge--that is, a description of the nature and magnitude of the risk, an interpretation of the adversity of the risk, a summary of the confidence or reliability of the information available to describe the risk, areas where information is uncertain or lacking completely, and documentation of all of the evidence supporting the characterization of the risk.... Risk assessment, therefore, informs decision makers about the science implications of the risk in question.... The primary purpose of a risk assessment is not to make or recommend any particular decisions; rather, it gives the risk manager information to consider along with other pertinent information. (7) To better understand the role of science in EPA, as manifested through risk assessment, this section focuses on defining risk and risk assessment, the role of policy and judgment, and procedures or practices the EPA uses to provide the highest quality information to decision makers.

   1. What is Risk?

      Risk is an inherent consequence of life that is not possible to altogether avoid or eliminate. (8) Risk is a very elusive and often contentious concept, but in general, it is a concept that denotes a potential negative impact or outcome that may arise from some present or future process. (9) The definitions of risk depend on specific contexts or applications, and there are multiple dimensions to risk, ranging from the tangible and quantitative to the psychological and emotional. Kaplan and Garrick describe risk as consisting of three components: 1) outcome(s), 2) likelihood, and 3) severity. (10) Most importantly, risk is the complete range of possible outcomes, their severity, and their likelihood, and not just the actual outcomes which have occurred or will actually occur. (11) Another critical dimension of risk is uncertainty--the fact that outcomes are uncertain makes them risk, and unavoidable. (12) These concepts are illustrated in the following quote:

      Reports that say that something hasn't happened are always interesting to me, because as we know, there are known knowns, there are things we know we know. We also know there are known unknowns, that is to say we know there are some things we do not know. But there are also unknown unknowns--the ones we don't know we don't know. And if one looks throughout the history of our country and other free countries, it is the latter category that tend to be the difficult ones. (13) Each of the italicized elements represents an aspect of risk.

   2. What is Environmental Risk?

      If risk generally is the potential negative outcomes arising from current or future processes, what does environmental risk mean? The environment is a complex and interconnected web of organisms, systems, and processes at various levels of organization. Environmental risks can be described as results from the stressors (natural or anthropogenic) which negatively impact these organisms, systems, and processes. (14) Any perturbation (stressor) that impacts this complex web of interdependent systems can have a multitude of potential outcomes. Figure 1 presents a conceptual model of the theoretical pathways and routes of exposure between stressors (and sources of stressors) and effects (endpoints) for human and ecological receptors. Further complicating the assessment of environmental risks is the fact that not only can there be a wide range of impacts associated with stressors in the environment, but environmental releases, fate and transport (environmental concentrations), exposures (contact), and biological responses will tend to vary both spatially and temporally. (15)

      While the phrasing is different in various statutes, and while different judicial interpretations certainly influence how...