Mechanisms and functional morphology associated with metal transport in Mercenaria mercenaria (Bavalvia: Mollusca): Final report, September 1, 1977--February 28, 1989

From September 1977 through July 1981 the primary goal of our research was to determine the effect of oil-well drilling muds on the commercially important bivalve species of Georges Bank. Studies included toxicological effects of various drilling mud components, research on energy stores and reproduction, effects of turbidity on feeding and digestion in both adult and larval bivalves, and the effects of drilling mud components on bivalve gills. Our findings implicated a variety of metals present in drilling muds as the purveyors of both lethal and sublethal effects, and prompted our subsequent work on the mechanisms of metal accumulation, detoxification and transport in marine bivalve molluscs (August 1981 through February 1989). Using radioactive cadmium (primarily) and silver, we have examined metal-storage compartments and kidney detoxification mechanisms in Mercenaria mercenaria. Results have shown that the kidney is the primary site of metal sequestration, due to both a low molecular weight metal-binding protein and numerous calcium phosphate granules. Metal transport experiments have shown that blood plasma proteins may play a major role in transporting metals to the kidney for sequestration and elimination. 31 refs.