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The cumulative MeHg and PCBs exposure and risk of tribal and US general population with SHEDS-multimedia
Citation:
Xue, J., V. Zartarian, AND K. Bailey. The cumulative MeHg and PCBs exposure and risk of tribal and US general population with SHEDS-multimedia. 2016 Annual International Society of Exposure Science Meeting, Utrecht, NETHERLANDS, October 09 - 13, 2016.
Impact/Purpose:
This work can inform Agency efforts providing guidance to state and tribal fish advisory programs. It is relevant to efforts by EPA Office of Water (OW), Regional offices, Office of International and Tribal Affairs (OITA), and the Office of Chemical Safety and Pollution Prevention’s (OCSPP’s) tribal group.
Description:
Studies have shown that the U.S. population continues to be exposed to methyl mercury (MeHg) and polychlorinated biphenyls (PCBs) due to the long half-life of those environmental contaminants. Fish intake of Tribal populations is much higher than the U.S. general population due to dietary habits and unique cultural practices. Large fish tissue concentration data sets from the Environmental Protections Agency’s (EPA’s) Office of Water, USGS’s EMMMA program, and other data sources, were integrated, analyzed, and combined with recent tribal fish intake data for exposure analyses using the dietary module within EPA’s SHEDS-Multimedia model. SHEDS-Multimedia is a physically-based, probabilistic model, which can simulate cumulative (multiple chemicals) or aggregate (single chemical) exposures over time for a population via various pathways of exposure for a variety of multimedia, multipathway environmental chemicals. Our results show that MeHg and total PCBs exposure of tribal populations from fish are about 3 to 10 and 5 to 15 times higher than the US general population, respectively, and that the estimated exposures pose potential health risks. The cumulative exposures of MeHg and total PCBs will be assessed to generate the joint exposure profiles for Tribal and US general populations. Model sensitivity analyses will identify the important contributions of the cumulative exposures of MeHg and total PCBs such as fish types, locations, and size, and key exposure factors. Biomarker data from NHANES will be used to evaluate SHEDS-Multimedia outputs. These exposure assessments can be used to help inform decisions regarding meal sizes and frequency, types of fish and water bodies to avoid, and other factors to minimize exposures and potential health risks from contaminated fish in Tribal populations and high exposure groups from the U.S. general population.
