Bioconcentration and Retention of 14C-hexachlorobenzene (HCB): II. The Estuarine Clam Mytella gyuanensis

摘要

HCB (hexachlorobenzene) is a persistent organic pollutant still detected in marine environments and organisms. The ability of the estuarine clam Mytella guyanensis to take up 14C-HCB from the sediment and to retain the contaminant within its tissues was studied in estuarine experimental microcosms. The sediment, water and soft tissues of the clams were periodically sampled and analyzed for their radiocarbon, HCB and lipid contents. Although most of the radioactivity remained in the sediment, some was found dissolved in the water, and 14C-HCB residues increased in the clam tissues with time of exposure to the HCB-spiked sediment. Further to its bioaccumulation, HCB was distributed within the mussel tissues as extractable and bound residues, which remained associated to the soft tissues even after restoration of uncontaminated conditions. Although M. guyanensis lives and feeds buried into the sediment, HCB uptake in the mussel was strongly influenced by the levels of HCB occurring in the water column. Levels of HCB in M. guyanensis were highly correlated with the lipid contents of its soft tissues.