Tissue-specific assimilation, depuration and toxicity of nickel in Mytilus edulis

The tissue-specific accumulation and time-dependent depuration of radioactive 63Ni by the byssus, gut, foot, gills, kidney, adductor muscle and faeces of Mytilus edulis has been investigated using a pulse-chase technique. The rate and extent of depuration of 63Ni varied between tissues and, after 168 h, the concentration factors and assimilation efficiencies ranged from 1 to 35 L kg−1 and 5%–13%, respectively. Mussels were also exposed to a range of environmentally-realistic concentrations of dissolved Ni, prior to the analysis of biological endpoints. The clearance rate was concentration-dependent and at the highest concentration decreased by 30%. Neutral red retention (NRR) assays indicated a cytotoxic response and DNA strand breaks were observed in the haemocytes. The association of DNA damage with that of physiological and cytotoxic effects suggests that Ni exerts a significant impact on Mytilus edulis at cellular and genetic levels.

► Tissue-specific accumulation and depuration of nickel by marine mussels was evaluated.
► Concentration factors for nickel in mussel tissues were lower than recommended values.
► Cytotoxic and genotoxic effects were detected in mussel haemocytes in the presence of dissolved nickel.
► Nickel exerts a significant effect on mussels at cellular and genetic levels.