IMPORTANCE OF DOSE-RESPONSE MODEL FORM IN PROBABILISTIC RISK ASSESSMENT - A CASE-STUDY OF HEALTH-EFFECTS FROM METHYLMERCURY IN FISH

We compared the effect of uncertainty in dose-response model form on h ealth risk estimates to the effect of uncertainty and variability in e xposure. We used three different dose-response models to characterize neurological effects in children exposed in utero to methylmercury, an d applied these models to calculate risks to a native population expos ed to potentially contaminated fish from a reservoir in British Columb ia. Uncertainty in model form was explicitly incorporated into the ris k estimates. The selection of dose-response model strongly influenced both mean risk estimates and distributions of risk, and had a much gre ater impact than altering exposure distributions. We conclude that inc orporating uncertainty in dose-response model form is at least as impo rtant as accounting for variability and uncertainty in exposure parame ters in probabilistic risk assessment.