Uncertainties in ecological, chemical and physiological parameters of a bioaccumulation model: implications for internal concentrations and tissue based risk quotients

Bioaccumulationmodelspredictinternalcontaminantconcentrations(ci) usingecological,chemical and physiologicalparameters.Hereweanalysetheeffectofuncertaintiesontheseparameterson bioaccumulationmodelpredictions.Simultaneouslyconsideringtheuncertaintiesonallthese parametersinabioaccumulationmodelresultedinuncertaintyrangesof ci that increasedwiththe octanolwaterpartitioncoefficient Kow and reachedmaximaofupto1.25logunitsformesozooplankton and upto1.45logunitsfishatlog Kow=8.Aglobalsensitivityanalysis(SA)wasperformedtorankthe contributionofdifferentparameterstotheobserveduncertainty.TheSAdemonstratedthatthis interspeciesdifferenceresultedpredominantlyfromuncertainproductionratesoffish.The Kow, the water concentrationandorganiccarbon–octanolproportionalityconstantwereimportantdriversof uncertaintyon ci for bothspecies.Atissuebasedriskquotient(RQtissue) combininguncertaintyon ci with realistictissuebasedeffectthresholdsindicatedthatfishwereupto10timesmoreprobableto have RQtissue41 thanmesozooplankton,dependingontheconsideredthresholdvalue.Conventional exposurebasedriskquotientswereupto5timeslessprobabletoexceedonethanwerecorresponding RQtissue, andthisforbothspecie