Mercury and the estuarine marsh clam, Rangia cuneata gray. II. uptake, tissue distribution and depuration

During a two-week period, Rangia rapidly accumulates mercury (as mercuric chloride) from dilute solution (0·03–0·05 ppm) with the majority being located in gill and mantle tissue. Initial depuration (5 h) in clean seawater is rapid in all tissues. From 10–192 h concentrations of mercury in gill, foot and adductor muscles remain stable while mantle, haemolymph and viscera levels continue to fluctuate in a manner suggesting internal redistribution of mercury. After eight days of depuration, the viscera contains the most mercury and appears to be the only tissue to increase its proportionate share of the total tissue mercury. After fifteen weeks of depuration, residual mercury in whole clams is about 20% of initial concentrations. Acute decreases in salinity (15% S to 2% S) enhance Rangia's ability to depurate mercury.