Determination of Cadmium–Metallothioneins in Zebra Mussels Exposed to Subchronic Concentrations of Cd²⁺

ISSN： 0147-6513

Source： Ecotoxicology and Environmental Safety, Vol.33, Iss.3, 1996-04, pp. : 246-252

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

Metallothioneins have been detected and investigated in zebra mussels (Dreissena polymorpha) using high-performance liquid chromatography (size exclusion) coupled with microatomization–AAS or inductively coupled plasma mass spectrometry. The mussels were exposed to 0.2, 2, and 20 μg/liter Cd²⁺(as CdCl₂) for 1 month under controlled temperature and dietary conditions. Elevated (relative to control) concentrations of tissue Cd²⁺were detected in all specimens exposed to 2 μg Cd/liter and more than 50% of the specimens exposed to 0.2 μg Cd/liter, demonstrating thatDreissenacannot regulate Cd²⁺at trace exposure concentrations. In most specimens, at least 85% of the measured Cd²⁺was bound to metallothioneins. After reduction and exposure to excess Cd²⁺, the metallothionein fraction of all extracts adsorbed similar quantities of Cd²⁺, indicating that the physiological concentration of metallothionein in the exposed specimens remained similar to the basal concentration in the control specimens. Thus, a short-term exposure to environmentally relevant concentrations of Cd²⁺did not produce a genetic induction of metallothionein biosynthesis as generally observed in specimens exposed to higher concentrations of d¹⁰metals.