Technical Critique of the Multimedia,Multipathway, Multireceptor Risk Assessment Model |
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Authors: | Nadine Weinberg Miranda Henning Michael Kladias Marc Killingstad |
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Affiliation: | 1. ARCADIS, Portland, Maine, USA;2. ARCADIS, Millersville, Maryland, USA |
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Abstract: | The U.S. Environmental Protection Agency (USEPA) is developing the Multimedia, Multipathway, Multireceptor Risk Assessment (3MRA) model to evaluate potential human and ecological risks associated with the disposal of solid wastes designated as hazardous wastes in nonhazardous waste management units. USEPA intends to use the 3MRA model to determine national exit levels that will allow solid wastes that theoretically pose acceptable human and ecological risks to be safely managed in Subtitle D nonhazardous waste management units. We critically evaluated the 3MRA model to determine whether the methodology, interim modules, and input parameters are appropriate and scientifically defensible. Overall, our review of the 3MRA model indicates that it contains many conservative assumptions that may limit the validity of the model results and its use as a national model adequate for making regulatory decisions. Many of the assumptions and data inputs used to model the pathways involved in the transport of chemicals from a waste management unit are flawed. Other specific concerns include the lack of model validation, incompatibility of data between modules, and overestimation of potential human and ecological exposures. Before using the 3MRA model, we recommend that USEPA consider whether the 3MRA model is either an appropriate or accurate tool for evaluating the disposal of hazardous wastes nationwide. |
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Keywords: | 3MRA Hazardous Waste Identification Rule exit level critique |
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