Jackson Estuarine Laboratory

Monitoring for toxic contaminants in Mytilus edulis from New Hampshire and the Gulf of Maine


Gulfwatch is an international monitoring program that uses Mytilus edulis as the sentinel species for habitat exposure to toxic contaminants in the Gulf of Maine. Since 1991, the Gulfwatch program has measured the concentrations of 10 trace metals, 17 chlorinated pesticides, 24 polynuclear aromatic hydrocarbons (PAHs), and 24 polychlorinated biphenyl (PCB) congeners in mussel tissue from over 60 sites throughout the Gulf of Maine. In 1998, the Gulfwatch program included a more intensive survey of sites in New Hampshire. Of the 21 sites sampled in the Gulf in 1998, six sites were sampled in New Hampshire and the other 15 sites were in Nova Scotia, New Brunswick, Maine, and Massachusetts. Results for the Gulfwide program showed a southward trend of increasing concentrations for organic contaminants and Ag, Cr, and Pb, reflecting major local and regional pollution sources. The distribution of the remaining trace metals was more uniform, without obvious impacts from the more heavily urbanized areas of the southern gulf. At some sites there appears to be localized hot spots for a variety of contaminants. Gulfwide geometric mean (GM) concentrations were lower than GM +85% confidence level (CL) concentration for the NOAA National Status and Trends (NS&T) Mussel Watch program, except for Hg. Two sites had Pb concentrations that exceeded U.S. FDA guideline levels. While Hg concentrations did not exceed the U.S. FDA action concentration at any site, the NS&T GM +85% CL was exceeded at all 1998 Gulfwatch sites. The spatially intensive New Hampshire program has been useful in identifying local sources of contaminants and determining the significance of mussel exposure to oil from chronic discharges and larger spills. Similar to comparisons between Gulfwatch and NS&T data, interpretation of New Hampshire results benefit from comparisons to the greater Gulfwatch program.

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Journal Title

Journal of shellfish research


National Shellfisheries Association

Document Type