Final Program - Society for Risk Analysis

W3-C.4 von Stackelberg KE; kvon@erisksciences.comE Risk Sciences, LLPWEIGHT OF EVIDENCE EVALUATION FOR ADVERSE HEALTH EF-FECTS OF SEVERAL PESTICIDES AT ENVIRONMENTALLY-RELE-VANT CONCENTRATIONSThere are many examples of epidemiological studies showing an associationbetween exposure to a compound and one or more adverse health outcomes that areonly weakly, if at all, supported by the available toxicological data. For example, epidemiologicalstudies have shown an association between exposure to chlorophenoxypesticides such as 2,4-D and MCPA and adverse health outcomes including Non-Hodgkins lymphoma, Hodgkins disease, and soft tissue sarcoma, while the toxicologicaldata, however, suggest that these compounds are not carcinogenic. Moreover,there is the question of biological plausibility. Given what we know about the etiologyof particular health outcomes, what is the evidence for the required steps in termsof pathways for these diseases to occur, and are those reasonable pathways with respectto mode of action of exposure to the constituents of interest (e.g., what is thehypothesized mode of action and how does that compare to what is known aboutdisease etiology). There is also the question of exposure, and what exposures wouldbe necessary or sufficient to lead to the particular health outcome. We develop aframework for evaluating the weight of evidence for adverse health effects followingexposure to 2,4-D, MCPA, and several other pesticides based on the epidemiologicaland toxicological data together with criteria related to biological plausibility. Finally,we integrate information on exposures, including a discussion of biomonitoring data,where available, to develop an integrated assessment of the weight of evidence forpotential health effects.P.41 von Stackelberg KE, Williams PRD; kvon@erisksciences.comE Risk Sciences, LLPQUANTITATIVE MODEL EVALUATION: LESSONS LEARNED FROMSYMPOSIA ON GETTING THE NUMBERS RIGHTModels are often used to support environmental decision making, and the predictivepower of these models is typically based on or can be evaluated using a varietyof calibration metrics. At the 2008 Annual SRA Meeting, we chaired two symposiaon quantitative metrics for model evaluation in environmental and occupationalhealth settings. In this presentation, we will synthesize and further explore the keythemes that emerged from these symposia discussions. In particular, we will discussthe use and limitations of different metrics, such as biomarker specificity withrespect to validating exposure estimates, population biomarker and biomonitoringdatasets to support exposure model development, and model to model comparisonsto evaluate individual model performance. We will also discuss the difficulty of usingMonte Carlo and related probabilistic simulation techniques for exploring uncertaintyin complex, integrated models and recommended strategies for incorporating anddeveloping uncertainty analyses in this context. This information will be useful foranalysts, modelers, and decision makers to consider during model development andlife cycle model evaluation.W2-G.1 Vorhees D, Strauss H, Heiger-Bernays W, Gopinathan B, Oruchin E,Stirrett-Wood G, Igbara J, Cowell W, Chien J, Dong Z; dvorhees@post.harvard.eduBoston University School of Public HealthHEALTH RISK ASSESSMENT OF EXPOSURES ASSOCIATED WITHNIGERIAN OIL FIELDSPeople living in the Ogoniland region of Nigeria attribute a range of adversehealth effects to petroleum releases to the environment. In 2010 at the request ofthe Nigerian government, the United Nations Environment Programme (UNEP) assessedconditions at over 300 sites affected by the release of petroleum from oil fieldoperations in Ogoniland. As part of this study, we designed and conducted a pilothealth study in collaboration with UNEP staff and scientists from the Rivers StateUniversity of Science and Technology in Port Harcourt, Nigeria. The study focusedon some of the most highly contaminated communities where people work primarilyas farmers and fishermen and was designed to determine (1) how people are exposedto petroleum, (2) whether these exposures might have adversely affected the healthof people, (3) what records are available to investigate health effects and whetherthey suggest that adverse health effects have occurred, (4) whether immediate actionis warranted to protect public health, and (5) how exposure monitoring and medicalrecord-keeping protocols can be improved to facilitate more detailed study. Datacollection included measurement of petroleum hydrocarbons in outdoor air, drinkingwater, rain water, and other environmental media, a survey of local communitymembers administered in person to ascertain patterns of exposure and self-reportedsymptoms and health conditions, and collection and analysis of primary health carecenter records. Some significant exposures were measured, notably benzene concentrationsin drinking water that were 8000 to 9000 times higher than the USEPA drinkingwater standard, but medical records and self-reported health information werenot sufficient to reach conclusions about effects on human health. Therefore, the presentationconcludes with recommendations for a prospective epidemiological studyin selected communities that is designed to include essential information unavailableduring UNEP’s pilot study.187