On January 12, 2011, an article was released on-line by the journal, Environmental Science & Technology, describing a new retrospective environmental fate and transport model that links several different modeling systems, including AERMOD, PRZM-3, BreZo, MODFLOW, and MT3DMS, to model historic environmental contaminant air dispersion, transit through the vadose zone, surface water transport, and groundwater flow and transport. The authors developed the model to generate retrospective predictions of historic exposures to perfluorooctanoic acid (PFOA) for use in epidemiologic analyses of thousands of people who used certain drinking water supplies in West Virginia and Ohio contaminated with PFOA. The authors modeled contaminant concentrations in air, surface water, groundwater and several municipal water systems, using historic industrial facility contaminant emission rates, physiochemical properties of the contaminant, and local geologic and meterological data going back to 1951. According to the authors, the linked modeling system (after adjustments) produces results that predict water concentrations for the several municipal water systems under study within a factor of 2.1 of the average observed water results, with a Spearman’s rank correlation coefficient of 0.87 for predicted versus observed water results, after model calibration. The authors note that the multicompartment model may be useful in estimating both historic and future contaminant concentrations in the water, and could be useful for epidemiologic analyses requiring retrospective exposure estimates. The article is available by clicking here.
For more information on environmental fate and transport modeling, please contact Rob Bilott or any member of Taft’s environmental practice group.