Shell weight as an independent variable in relation to cadmium content of mollusks

Abstract

ABSTRACT: Shell weight of molluscs is introduced as alternative parameter for biological monitoring of heavy metals. Variability of metal concentration due to variations in soft-body weight can eliminated by relating metal body burden to shell weight. A reformed 'Mussel Watch' concept outlined. Detailed investigation of Cd in mussels exemplifies advantages of the new approach. relation of Cd body burden to shell weight is constant in relation to environmental Cd concentration. contrast, conventional Cd concentration values of soft tissues, in general, are related to the physical condition of mussels. The dependency of condition and Cd concentration on individual size, exposure, spawning, and nutrient supply is documented. Accumulation of Cd in soft tissues formation of the calcareous shell are discussed in terms of influx of environmental ions and organismic immobilisation, together with their respective organic ligans.