Ecological Risk Assessmentof Rodenticides:ofRodenticides:Analysis PlanPresentation to the SAPNovember 29th, 2011EdwardOdenkirchen, Ph.D.,Ph.D.Environmental Fate and Effects Division1Purpose of the Evaluation•Provide information on the ecological risks associatedwith the rodenticide active ingredients in products thatare the subject of the Notice of Intent to Cancel (NOIC)arethesubjectoftheNoticeofIntenttoCancel(NOIC)•Update existing data sets•Toxicity data•Body burden informationBodyburdeninformation•Incident information•Conduct deterministic risk assessments using updatedinformation and most recent methodsinformationandmostrecentmethods•Analysis of incident data with respect to•Expected route of exposure•Land use characteristicsLandusecharacteristics•Evaluation of all lines of evidence for consistency in therisk conclusions•Consider risk conclusions as they relate to mitigationConsiderriskconclusionsastheyrelatetomitigationmeasures in the Risk Mitigation Decision (RMD)2Rodenticides Evaluated•4 active ingredients under the NOIC•3 anticoagulants:•Brodifacoum*•Difethialone*•Warfarin**•1 neurotoxin1neurotoxin•BromethalinHas conforming and non-conforming labels•2 likely replacement active ingredients that have conforminglabels (both anticoagulants)•Chlorophacinone**•Diphacinone***Known as a“second generation”anticoagulantKnownasasecondgenerationanticoagulant**Known as a “first generation” anticoagulant3Taxonomic Groups Potentiallyat Risk•RMD focused on steps to mitigateRMDfocusedonstepstomitigateconcerns for terrestrial wildlife risks•Results ofprevious assessment work•Multiple lines of evidence (high toxicity,bioaccumulation exposure potential andbioaccumulation,exposurepotentialandincidents) suggest that primary riskconcern is for terrestrial animals (ieconcernisforterrestrialanimals(i..,birds and mammals)4Measures of Risk•Deterministic Risk Quotients (RQ)Exposure estimate/toxicity endpoint = RQE E ti t•ExposureEstimates•Primary: Direct consumption of bait•Secondary: Consumption of prey contaminated through directconsumption of bait•Utilize peer-reviewed exposure calculations (Wildlife Exposure FactorsHandbook, EPA 1993)•Effects endpoints•Acute lethal endpointsAcutelethalendpoints•Dose-based•Dietary-based•Efforts to standardize analysis•Body weight scaling to account for interspecies differences (variety ofBodyweightscalingtoaccountforinterspeciesdifferences(varietyofmethods)•Interpretative Method•RQ compared to non-listed species Level of Concern (LOC=0.5)5Characterization and Comparisonsof Risks Across Chemicals•Primary Exposure•Amount of bait required to reach medianl th l dlethaldose•Number of days of feeding required to reachmedian lethal dosemedianlethaldose•Secondary Exposure•Number of target animals required to reachNumberoftargetanimalsrequiredtoreachmedian lethal dose•Results of secondaryfeedingstudiesg6Assessment Methods - Incidents•Document incidents of exposure andmortalities•primaryand secondaryexposurey yp•mammals and birds•Document location of incidentsDocumentlocationofincidents•Related to urban/suburban areas thatrepresent use sites for commensal rodentcontrol products•Concurrence with other lines of evidence7Risk and Mitigation Measures•Conclusions are qualitativeConclusionsarequalitative•Bait station/solid bait requirement•Limitation of application distance fromstructure•Point of sale and material mass basedlimitations to home-owner use8Organization of Presentations•Toxicity Data•Primary Deterministic Risk Assessment•Secondary Deterministic Risk Assessment•Incident DataIncidentData•Conclusions based on all lines of evidence•Discussion of risk conclusions and risk mitigationmeasures9