Effects of sediment composition on cadmium bioaccumulation in the clam Meretrix meretrix Linnaeus.

Sediment particulates can be ingested by benthic animals, and the bioavailability of associated metals strongly depends on their speciation in the sediments. Different sedimentary components have distinct physiochemical characteristics and result in different biological responses from animals. Therefore, the bioaccumulation of particle-bound trace metals may be different. In the present study, bioaccumulation of cadmium adsorbed on various (hydr)oxide minerals, that is, ferric hydroxide, aluminum hydroxide, and manganese dioxide, in the clam Meretrix meretrix Linnaeus was studied. The results showed that the accumulation rate of cadmium varied for different mineral-adsorbed cadmium. The bioaccumulation of metal (hydr)oxide-adsorbed cadmium in M. meretrix followed the order Cd-MnO2  > Cd-Al(OH)3  > Cd-Fe(OH)3 . The type of mineral determines both the assimilation efficiency and ingestion rate, and consequently controls the bioaccumulation of adsorbed cadmium.