Final Program - Society for Risk Analysis

dose for a variety of exposure scenarios. This information was coupled with informationon the rate of repair to determine whether an acute exposure limit is adequatelyhealth protective, or whether one also needs to evaluate the exposure relative to the(more restrictive) chronic limit. It should be noted that these relatively simple examplescannot capture all of the complex considerations and issues that may be relevantto the risk characterization process for a particular chemical or exposure scenario,but represent the most common considerations within the proposed framework. Thegeneric kinetic model is a work in progress, thus further review and enhancement ofthe method is needed.M4-J.2 Parvez S, McCurry D, Rice GE, Teuschler LK, Speth TF, Miltner RJ,Pressman JG; parvez.shahid@epa.govOak Ridge Institute for Science and EducationCOMPARISON OF CHEMICAL COMPOSITION OF COMPLEX DISIN-FECTION BYPRODUCT (DBP) MIXTURES PRODUCED BY DIFFER-ENT TREATMENT METHODSAnalyses of the chemical composition of complex DBP mixtures, producedby different drinking water treatment processes, are essential to generate toxicity datarequired for assessing their risks to humans. For mixture risk assessments, whole mixturetoxicology studies generally are preferred to component studies. A concern withwhole mixture studies is the similarity of the tested mixture to the mixture of concernin the environment. We evaluated the chemical composition of three chlorinatedDBP mixture concentrates (A, B, C) formed by different concentration methods.We compared their DBP composition to a reference chlorinated mixture (R) at 1xdilution of the disinfected source water. Tukey studentized tests and statistical powertests were performed (at a = 0.2, 0.1, 0.05, 0.01) to examine differences among 19individual DBPs and 4 DBP classes. Preliminary results suggested concentrate C andR are similar except for levels of 3 individual DBPs. Concentrates A and B differedsignificantly from C and R based on concentrations of trihalomethanes, haloaceticacids, total organic halogens (TOX), and other individual DBPs. Statistical analyses atdifferent a levels yielded consistent results for most of the DBP fractions includingTOX, suggesting that these results are robust. However, the percent TOX associatedwith measured individual DBPs (MTOX) and unknown (UTOX) fractions variedacross the concentrates; MTOX and UTOX each comprised ~50% of TOX in R; inconcentrates A, B, and C, the percentage of UTOX was 70%, 70%, and 64%, respectively.This suggested that among the three concentrates, concentrate C is quite similarto R for measured DBPs and MTOX, but the UTOX fractions of all concentratesdiffer. We conclude that the concentrate C has DBP concentrations that are mostsimilar to that of R. [The views expressed in this abstract are those of the authorsand do not necessarily reflect the views or policies of the U.S. EPA.]P.109 Pato A, Sosa Holt C, Wolansky MJ; mjwolansky@gmail.comUniversity of Buenos Aires/Argentine National Research CouncilRAT THERMOREGULATION: EXPLORATION OF ITS VALUE INRISK ASSESSMENT OF MIXTURES OF TYPE I AND TYPE II PYRE-THROID INSECTICIDESPyrethroid insecticides produce changes in thermoregulatory response (TR)in small rodents. In rat, type I-pyrethroids permethrin (PM) and bifenthrin (BIF)produce hyperthermia, and type II cypermethrin (CPM) and deltamethrin (DLM)produce hypothermia. These structure-specific TR effects have been mostly demonstratedusing moderately high-effective doses and rectal probe measurements aftersingle oral dosing. In addition, CPM and DLM have been reported to produce biphasicdose-effect relationships: mild hyperthermic effects at low doses, and the expectedhypothermia at greater dosages. At present, there is insufficient data to establish if thejoint neurotoxicity of pyrethroids is influenced by the structure-specificity of the endpointselected for study. In order to explore structure- and dose-related actions, weobtained time- and dose-effect relationships for above pyrethroids using mini-transpondertechnology (BMDS, USA). These telemetry-based chips collect and transmitreal-time, subcutaneous body temperature (T). Adult Wistar rats (8-9 weeks old) wereimplanted ~96 h before testing and TR was monitored to determine individual physiologicalbaselines. Temperature data were collected at 30 min intervals for 5 hr after asingle oral dose (~1-20% LD50; 1 ml/kg) of each compound dissolved in corn oil (N= 6-8 per dose group). The expected type I- and II-like TR patterns were observed athighly effective doses (in mg/kg: PM 150, BIF 12, DLM 9, a-CPM 15). However, amild increase in T was observed for all pyrethroids at a much lower dose regardless ofstructure. These preliminary results suggest that the dual, type I/II classification onlymay be a high-dose effect. This testing protocol was capable of detecting pyrethroidtime-, dose-, and structure-dependent effects, what may be useful in the context ofexamining pyrethroid mixtures in ongoing risk assessment efforts (work in progress).P.118 Pearce JM, Rogers MB; julia.pearce@kcl.ac.ukKing’s College LondonRISK AND CRISIS COMMUNICATION REQUIREMENTS FOLLOW-ING AN ACUTE CHEMICAL INCIDENTA long-standing but rapidly growing literature indicates that effective publiccommunication forms an essential part of any emergency response programme.However, a number of risk communication barriers around chemical incident emergencieshave been identified. This poster presents the findings of the risk and crisiscommunication work package of a recently completed European Commissionfunded project, the Chemical Incident Emergencies Toolkit (CIE Toolkit). This studywas designed to improve understanding regarding public health information needsand behavioural intentions in relation to a chemical incident. Focus groups were con-157