An ecologically framed mercury survey of finfish of the lower Chesapeake Bay.

Total mercury (THg) and methylmercury (MHg) concentrations and determents of mercury (Hg) accumulation were examined for muscle tissues of 10 finfish from the lower Chesapeake Bay (LCB) and its tributaries. There was no suggestion of potential human harm from Hg due to LCB fish consumption: None of the sampled fish had THg concentrations approaching the United States Environmental Protection Agency human health screening value. Hg concentrations in different fish species generally increased with the increasing stable isotope of nitrogen 15 (δ(15)N) but not the stable isotope of carbon 13 (δ(13)C), thus suggesting that trophic position but not dietary carbon source is a dominant determinant. An MHg biomagnification model was built to estimate a food web magnification factor of approximately 10-fold increase per trophic level. Based on otolith strontium-to-calcium ratios, Atlantic croaker inhabiting less saline waters might accumulate more Hg than those inhabiting more saline waters. The SAS mixed procedure identified significant positive intraspecies relationships between MHg concentration and δ(13)C for summer flounder, weakfish, American eel, Atlantic croaker, and spot.