Involvement of metallothionein in cadmium accumulation and elimination in the clam Ruditapes decussata

Abstract

Cadmium is one of the most toxic pollutants in seawater because of its persistence, toxicity and potential for bioaccumulation. It is included on the [open quotes]black list[close quotes] of several international agreements established to regulate the input of pollutants into the marine environment. The deleterious effects of cadmium contamination in marine organisms result from its accumulation within specific tissues. However, most of these organisms have developed subcellular detoxification processes, including the synthesis of metallothioneins, low-molecular weight, metal-binding proteins. Bivalves have the ability to accumulate and concentrate cadmium to levels several orders of magnitude above those found in their environment. The present study was designed to examine the involvement of metallothionein synthesis in cadmium accumulation and elimination in the bivalve Ruditapes decussata when exposed to a sublethal cadmium concentration (100 [mu]g/l) and to a mixture of cadmium (100 [mu]g/1), copper (50 [mu]g/l) and zinc (50 [mu]g/1). 15 refs., 2 figs., 1 tab.