Ecologically-framed Mercury Database, Exposure Modeling and Risk/Benefit Communication to Lower Chesapeake Bay Fish Consumers

作     者：Xu, Xiaoyu 

作者单位：The College of William and Mary 

学位级别：Ph.D.

导师姓名：Newman, Michale

授予年度：2013年

主      题：M e r c u r y , m e t h y l m e r c u r y , t r o p h i c e c o l o g y , b i o m a g n i f 

摘      要：Mercury concentrations and determinants of mercury accumulation were examined for ten finfish species from the lower Chesapeake Bay and its tributaries. None of the sampled fish had total mercury concentrations approaching the U.S. EPA human health screening value. Mercury concentrations in different fish species generally increased with increasing δ 15N, but not δ 13C, suggesting that trophic position, but not dietary carbon source was a dominant determinant. A methylmercury biomagnification model was built to estimate a food web magnification factor of approximately 10-fold increase per trophic level in Chesapeake Bay. Based on otolith strontium-calcium ratios, Atlantic croaker inhabiting less saline waters might accumulate more mercury than those inhabiting more saline waters. Positive intraspecies relationships between methylmercury concentration and δ 13C were identified for summer flounder, weakfish, American eel, Atlantic croaker, and spot. Fish consumption and associated mercury exposure were explored for two ethnic (Chinese and Vietnamese) church communities along coastal Virginia, as well as two general population (non-Asian) churches in this region. Individual seafood consumption rates for the ethnic communities were higher than the general U.S. fish consumption rate of 12.8 g/person/day. People from the general population churches and Chinese church took in most of their mercury from market fish (distributed and sold nationally) whereas people from the Vietnamese church took in mercury from both the market and local fish as they tended to eat a large amount of diverse local species. Hair mercury concentrations in the Chinese and the Vietnamese church were higher than the overall level for U.S. women (0.20 μg/g), but lower than the published WHO exposure threshold of 14 μg/g. Regression between seafood consumption rates and hair mercury concentrations suggested that dietary mercury ingestion through seafood was positively related to mercury exposure. Merc