Environmental Risk Assessment and Management from a Landscape Perspective (Kapustka/Environmental Risk) || Ecological Risk Assessment toward a Landscape Perspective

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<ul><li><p>2ECOLOGICAL RISK</p><p>ASSESSMENT TOWARD ALANDSCAPE PERSPECTIVE</p><p>Lawrence A. Kapustka</p><p>The fundamental concepts of risk assessment are imbedded in our cultural prehistory.Then of course the considerations were intimately linked to daily survival: Was itsafe to cross a river, attack a woolly mammoth, eat the camas bulbs, or enter theterritory of hostile neighbors in search food, shelter, and treasure? Scientific inquiryenabled improved understanding of connections between events and consequences.For example, efforts by Pasteur and Koch established a basis for managing bacterialcontaminants and thereby develop safeguards against diseases.</p><p>The application of risk assessment and risk management to biological situationslikely grew out of the science of epidemiology. Epidemiology, the study of diseasesin populations (Schwabe et al. 1977), emerged as a formal discipline in the late1800s following a severe cholera epidemic in London. The cause of the epidemicwas traced to contaminated drinking water, and the solution was simple: Remove thepump handles from the contaminated wells. The process that was used to make thediagnosis and find the solution represented a new way of thinking, one that searchedfor patterns and traced linkages that could explain the observed phenomenon.</p><p>But formal constructs of risk assessment as we know them today are relativelynew. Though at one level, the procedures appear to be simple and the math is generallyelementary, the execution of the procedures quickly becomes complicated. The manydecisions that must be made in setting up an assessment, though none individually mayseem very challenging, can become daunting with the interconnectedness of the suite</p><p>Environmental Risk and Management from a Landscape Perspective, edited by Kapustka and LandisCopyright 2010 John Wiley &amp; Sons, Inc.</p></li><li><p>12 ECOLOGICAL RISK ASSESSMENT TOWARD A LANDSCAPE PERSPECTIVE</p><p>of decisions. Perhaps as illustrated in the popular expose on the human psyche, Blink(Gladwell 2005), we are ill-equipped to address such complexities. Experts are easily,often unwittingly, diverted by their prejudices and can make monumental errors injudgment. The strong focus on chemical stressors, along with simplistic and outdatedexplanations of how ecological systems work, may indeed lead us to develop highlyprecise descriptions of risks that are precisely wrong. In the collection of chaptersin this book, we proffer the landscape and systems perspectives as improvements tothe risk approaches, especially when integrated into tools from the field of decisionscience. Mistakes will still be made, but hopefully fewer and with better chance forcorrections. To set the stage, I first examine the basic features of contemporary riskassessment.</p><p>RATIONALE FOR RISK ASSESSMENT</p><p>The origin of formal risk assessment can be traced to the insurance industry (Suter,2008). Actuarial tables aided the search for patterns of mortality in specific age groupsand provided clues to link behaviors and lifestyles to the patternsthe foundation ofinsurance premiums. The art of describing the occurrence of death or morbidity linkedto putative causal factors (epidemiology) could be used to forecast events (a form ofquantitative risk assessment) and design remedial actions. With the dawn of the age ofchemicals following World War II, efforts were made to link chemical contaminationin food and adverse health consequences. Approaches established by the early 1980sform the core of risk assessment as it is currently practiced (NRC 1983, US EPA1992, 1998).</p><p>Our basic aversion to external risk, those occurring beyond our control, led author-ities in search of a number that represented zero risk, or at least a probability so lowthat statistical sampling would be unable to distinguish the value from zero. Theetiology of this number representing essentially zero risk was traced in a delightfulpaper (Kelly 1991) that details how the arbitrary value of one in a millionthat is,106 became a de facto safe threshold in human health risk assessments.</p><p>Formal constructs for dealing with human health risk assessment were in placebefore ecological risk assessment (EcoRA) was developed, and they had great influ-ence on the procedures used to evaluate ecological risks. In many ways this wasunfortunate, because throughout the development of ecological approaches, there werepressures to establish a structure that paralleled the human health risk assessment pro-cess. There are many fundamental similarities, but also many differences. Perhapsthe greatest shortcoming arises from considering the target receptors (human or oth-erwise) at the organism level, which often divorces the subjects from the dynamicinteractions they really experience in their ecological setting. Separation of humanand ecological risk procedures, in addition to creating unnecessary compartmentation,led to two lexiconsoften having identical terms, but with different definitions orusage. This leads to communication challenges that become especially difficult for theend users of the risk information. When compartmentalized, separate risk assessmentsfor humans and for all ecological receptors can cause much frustration. Against this</p></li><li><p>ASSESSMENT TIERS 13</p><p>backdrop, there is a challenge to develop a holistic approach that merges these twoparallel approaches into one integrated realm that could improve the usefulness ofthe entire effort (Kapustka et al. 2008; also see Chapter 8). A holistic assessment,by extension of the multiple interactions, demands an assessment with a landscapeperspective.</p><p>Near-term and long-term environmental and socioeconomic effects of environ-mental planning options must be characterized and evaluated to understand both thebenefits and consequences of each option. A formal Environmental Risk Assessment(EnRA) can minimize unwanted or unexpected consequences by identifying thoseactions most likely to be harmful to humans or ecological resources and ranking theacceptable and unacceptable effects of the various options. Consideration of only short-term profits or benefits from the use of environmental resources will likely produceharmful long-term environmental consequences. Proper use of the risk assessmentprocess will identify threats to environmental resources and allow decision-makers toselect management options that have the least negative impact.</p><p>A formal risk assessment process has several advantages as applied to environ-mental planning and management of hazards (Suter 1993):</p><p> It can provide the quantitative basis for comparing and prioritizing risks. It can provide informed, science-based input for benefitcost analyses. By expressing results as probabilities, it acknowledges the inherent uncertainty</p><p>in predicting future environmental states, thereby making the assessment morecredible.</p><p> It separates the scientific process of estimating the magnitude and probabilityof effects from the process of choosing among alternatives and determining theacceptability of risks.</p><p>The last point is clearly the most important argument in favor of the risk assess-ment process. Values, biases, and societal influences define the questions asked inthe risk assessment process and influence the management decisions. However, theprocesses for determining the threat from a proposed action and magnitude of theexposure to stressors are grounded in the sciences. Characterization of the probabil-ity that an adverse outcome will occur as a result of the exposure to the stressor inquestion also is based on interpretation of science-based facts. The results of a riskcharacterization should be stated as a probability that an event will occur, because theoccurrence of future effects in ecological systems cannot be predicted with certainty.This is not merely a limitation of the science. Rather, it is an acknowledgment of thevariable and chaotic patterns of ecological systems. A risk assessment can also providea series of probabilities that an adverse effect will occur under different scenarios.</p><p>ASSESSMENT TIERS</p><p>The assessment process generally is staged with the initial stages (i.e., scoping andscreening) designed to be quick and relatively inexpensive. The early assessment stages</p></li><li><p>14 ECOLOGICAL RISK ASSESSMENT TOWARD A LANDSCAPE PERSPECTIVE</p><p>Scoping</p><p>Screening</p><p>Definitive</p><p>Possible</p><p>PlausibleDe</p><p>fault t</p><p>o Emp</p><p>irical</p><p>Probable</p><p>Exposure Assumptions</p><p>Figure 2.1. Progression from default assumptions toward empirical evidence in risk assess-ment.</p><p>use broad-brush assumptions that skew the outcome in a manner that minimizes thechances of making Type II errorsthat is, declaring a situation to be safe when itis not. These early stages are intended to narrow the focus of definitive assessments,if needed, onto the important questions. Basically, these different stages move fromhighly protective assumptions (e.g., ones that assume toxicity responses at the lowestconcentrations and realization of maximum exposures) to ones that more closely alignwith the real-world setting for the situations in question (Fig. 2.1, Table 2.1).</p><p>A most important aspect of these scoping/screening efforts is that the triggers orbright lines relating to environmental concentration (or equivalent measurement ofmagnitude for other stressors) are to be used in a one-way test. That is, if the con-centration of a chemical of interest is below the threshold, then the risks are deemedto be in the de minimis zone and are dropped from further consideration (Fig. 2.2).However, if concentrations are above the threshold, then further evaluation may bewarrantedthat is, site-specific factors affecting bioavailability or other moderating</p><p>Table 2.1. Degree of Rigor and Content in Risk Assessment Tiers</p><p>Tiers Content</p><p>Scoping (Tier 1) CoarseMinimum data acquiredHighly protective default assumptions</p><p>Screening (Tier 2) Some refinementMore data acquiredStill relying on protective default assumptions</p><p>Definitive (Tier 3) Finer detailConsiderable data acquiredGreater realism replaces default assumptions</p></li><li><p>ASSESSMENT TIERS 15</p><p>No AdverseConsequencesExpected</p><p>AdverseConsequencesPresumed</p><p>Environmental Realism</p><p>Low</p><p>Hig</p><p>h</p><p>Default Assumptions Site-specific Data</p><p>Actual Threshold Adverse ConsequencesMay be Demonstrable</p><p>Envi</p><p>ronm</p><p>enta</p><p>l Con</p><p>cent</p><p>ratio</p><p>n</p><p>Default Threshold</p><p>Definitive</p><p>Screening</p><p>Scoping</p><p>Figure 2.2. The iterative nature of environmental risk assessments.</p><p>aspects affecting exposure can be evaluated. Protective (default) thresholds are inten-tionally set substantially below the expected true threshold to minimize Type IIerrors.</p><p>Thus, if the scoping or screening assessments provide insufficient evidence todismiss stressorreceptor combinations, then refinements using more realistic assump-tions are incorporated in the next tier. The intent is to reduce uncertainty as greatersite- or case-specific information is incorporated into the risk assessment.1 The testused to decide whether to continue toward a definitive risk assessment is whether thereis sufficient information to make the (informed) environmental management decisionscalled for (Fig. 2.3).</p><p>Allard et al. (2010) have noted that hazard quotients (HQ) should be restricted touse in screening or hazard assessments of chemicals. The assumptions used are suchthat when a chemical exposure is compared to a toxicity threshold (e.g., TRV), thatan HQ &lt; 1 becomes a default de minimis value. The assumptions are intentionallyskewed toward protectiveness to avoid Type II error (i.e., to conclude that there isnot significant or unacceptable hazard when in fact there is). However, given thehigh probability of a Type I error (i.e., to conclude unacceptable risks when in fact</p><p>1Assessors and end-users of assessment conclusions should be cognizant of the possibility for greateruncertainty as refinements are introduced. This may occur particularly if the refinements impose newassumptions, as often is the case with computational models, or if new data gaps pertaining to the additionalparameters reduce the number of significant figures that can be justified in the outcome.</p></li><li><p>16 ECOLOGICAL RISK ASSESSMENT TOWARD A LANDSCAPE PERSPECTIVE</p><p>?</p><p>?</p><p>ScopingProblem Formulation Analysis Risk Characterization</p><p>No</p><p>Yes</p><p>ScreeningProblem Formulation Analysis Risk Characterization</p><p>FinalProblem Formulation Analysis Risk Characterization</p><p>Decision</p><p>No</p><p>Yes Decision</p><p>Decision</p><p>Figure 2.3. Relationship of different degrees of rigor in EcoRA and actual environmentalconcentrations.</p><p>there are none), HQs 1 typically require further studies to refine uncertaintiesbefore making risk management decisions. Hope (2008) and Allard et al. (2010) havedrawn a distinction between the early stages of scoping or screening as merely beinghazard assessments and not risk assessments because the hazard assessments lack bothprobability and magnitude terms.</p><p>But what happens if chemical stressors are not the most important factors deter-mining the continuation of a valued ecological resource or a human community? Theprocedures that work quite well for known chemical stressors may fail to forewarnabout companion stressors that have little or nothing to do with the chemicals: the haulroads severing the continuity of migration routes of caribou; housing developmentsin the winter range for elk; day-use parks that bisect the foraging range of cougar;the blockage of streams used for spawning salmon; the influx of workers who maybe insensitive to the cultural ethos of an aboriginal community. The structure of riskassessments to address the narrow constructs of chemical impacts seem adequate inmany instances. However, consideration of other stressors requires that we step backto see how we might improve the processto include habitat requirements for thespecies of interest and to capture to proper scales of space and time so that culturaldynamics are reflected in the resulting characterizations of risk that are relevant to theaffected stakeholders.</p><p>THE RISK ASSESSMENT PROCESS</p><p>Risk assessment, whether in finance, engineering, human health, ecological, or a holis-tic construct, is structured to evaluate one or more scenarios to predict qualitatively orquantitatively the likelihood of some event occurring. The focus may be viewed from</p></li><li><p>THE RISK ASSESSMENT PROCESS 17</p><p>either side of a riskreward divide: What is the chance I may win in blackjack if Imholding two eights? If Im the dealer, what is the chance I will have to payout if Ihit 17? A regulator mandated with protecting humans and ecological resources, butwithout frivolously burdening industry with sets of interventions, referees a very chal-lenging situation of keeping the house honest. Among stakeholders, there are somewho must see both sides of the riskreward conundrum. If more stakeholders couldgain a deep-seated appreciation of the process, the uncertainties, and the certitudes,we might be able to proceed with less contentious encounters. In the descriptions ofthe process that follow, we attempt to illustrate the challenges faced in getting theproper focus for a risk assessment. The analysis will lead to the cl...</p></li></ul>


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