Contamination in Chesapeake Bay and Delaware Estuary: Results from the NOAA NS and T program

Since 1986, the NOAA National Status and Trends Program through its Mussel Watch Project has been collecting and analyzing sediments and bivalves (oysters and mussels) at about 350 sites distributed around the United States. Since 1984, sediments where also collected and analyzed through the Benthic Surveillance Project. The data used for the sediments include most of the data previously available as well as the NOAA newly developed COSED data base. The analysis includes 17 trace metals and over 70 organic compounds. When comparing the results obtained for the bivalves collected in the Chesapeake Bay and the Delaware Estuary to those obtained in the rest of the United States, it appears that the concentrations of Cd in Chesapeake and Cd, Ni, and total DDT in Delaware Estuary, are high. In an effort to understand the reasons for these high concentrations, the authors compared bivalves and sediments data in relation to the various inputs (including river transport, point source, urban runoff and atmospheric deposition) to these estuarine systems. From this study, it appears that depending on the compound and on the location, natural and/or anthropogenic inputs are responsible for the observed concentrations. For example, in Chesapeake Bay, urban runoff and riverine transportmore » appear to play major roles.« less