Multimedia health risk assessment: A case study of scenario-uncertainty

Assisted by framework of multimedia total exposure model for hazard waste sites (CalTOX), potential influences of scenario-uncertainty on multimedia health risk assessment (MHRA) and decision-making were quantitatively analyzed in a primary extent under the Chinese scenario case by deliberately varying the two key scenario-elements, namely conceptual exposure pathways combination and aim receptor cohorts choice. Results show that the independent change of one exposure pathway or receptor cohort could lead variation of MHRA results in the range of 3.6×10−6-1.4×10−5 or 6.7×10−6–2.3×10−5. And randomly simultaneous change of those two elements could lead variation of MHRA results at the range of 7.7×10−8-2.3×10−5. On the basis of the corresponding sensitivity analysis, pathways which made a valid contribution to the final modeling risk value occupied only 16.7% of all considered pathways. Afterwards, comparative analysis between influence of parameter-uncertainty and influence of scenario-uncertainty was made. In consideration of interrelationship among all types of uncertainties and financial reasonability during MHRA procedures, the integrated method how to optimize the entire procedures of MHRA was presented innovatively based on sensitivity analysis, scenario-discussion and nest Monte Carlo simulation or fuzzy mathematics.