Date of Award
Master of Arts in Marine Affairs
Dennis W. Nixon
Well over a ton of metals such as cadmium, chromium, copper, lead, mercury, nickel, and zinc (dissolved in industrial effluents and sewage treatment plant discharges) enters Narragansett Bay on a daily basis. The Bay also supports a tremendous hard shell clam fishery with annual landings exceeding six million dollars. Levels of copper in upper Narragansett Bay water suggest that productivity of clam populations in areas currently open to commercial shellfishing may be impaired and that considerable economic loss.es result.
Tissue levels of cadmium, copper, chromium, lead and zinc in clams are monitored by the Rhode Island Department of Health and do not appear to pose any significant health hazards at present. Levels of lead, however, often approach the recommended limit of 2 mg/kg and in a couple of instances have actually exceeded this limit in areas currently closed to shellfishing because of bacterial contamination. Although the only official regulatory limit for metals in shellfish is one promulgated for mercury, this metal is not currently monitored. Hence, the health hazard of mercury in Narragansett Bay shellfish is unknown at present.
Horsley, Scott W., "Trace Metal Pollution in Narragansett Bay A Case Study of the Rhode Island Quahog Fishery" (1981). Open Access Master's Theses. Paper 2109.