Kinetics of vanadium bioaccumulation by the brackish water hydroid Cordylophora caspia (Pallas)

摘要

Vanadium is an abundant metal, which enters the environment via natural rock leaching. A large fraction however, enters the environment through the combustion of coal or petroleum products, which can contain high vanadium concentrations of biological origin. In steel industry vanadium is used as an alloy, therefore, the residual slag stones of steel production can contain rather high concentrations of this heavy metal. Since slag stones are increasingly used in riverbank reinforcement and since it is known that vanadium can leach from these artificial stones into the aquatic environment current interest arose on the toxicity of vanadium towards aquatic organisms. Vanadium, inhaled by humans as vanadium pentoxid, accumulates mainly in hair, liver. kidney and bones (Nechay et al. 1986) and causes several health hazards (for review see: Philipps et al. 1983). For the aquatic environment, very little is known about accumulation in biota and about toxic effects arising in invertebrates. Apart from studies with several ascidian species, which are known to accumulate vanadium from sea water up to the 10(6)-fold (Michibata et al. 1989) sparse information exists on accumulation of vanadium by invertebrates. Ringelband & Karbe (1996) showed that vanadium inhibits the colonial growth of hydroids, and that it acts as a potent inhibitor of hydroidal Na-K-ATPase. Up to now, very little is known about the biokinetic behaviour of vanadium in hydroids. The aim of the present study is to determine accumulation kinetics of vanadium in the brackish water polyp Cordylophora caspia. Cordylophora caspia is a colonial polyp (fam.: Clavidae) with optimal population growth in brackish water with salinity ranging between 10 and 16 parts per thousand (Kinne 1956). Hydroids are particularly sensitive to heavy metals and they serve as test organisms in a well-established population growth test (Stebbing. 1976, Karbe et al. 1984). [References: 12]