Cadmium , Zinc and Copper Accumulation in Limpets ( Patella vulgata ) from the Bristol Channel with Special Reference to Metallothioneins

The study of metal concentrations in Patella vulgata caught from a polluted environment reveals a direct relationship between Cd concentration and body size and an inverse relationship in regard to Zn and Cu. Most of the Cd present in limpets with heavy Cd loads is bound to thioneins, but this is not the case for Zn and Cu. In young limpets, Cd-thioneins were not detected. All results indicate that during long-term Cd intoxication under field conditions, Cd deposition and increase in metallothioneins in limpets were directly linked. The induced production of metallothioneins may thus be considered as the main mechanism responsible for the cumulative absorption of Cd in limpets living in the Bristol Channel. Isolation and characterization of limpet metallothioneins were performed. They indicate that mollusc metallothioneins are very similar to those from vertebrates.