Short-term effects of metals on the filtration rate of the zebra mussel Dreissena polymorpha

Abstract

In order to study the short-term ecotoxicity of metals to the freshwater mussel Dreissena polymorpha, the effects of Cu, Zn and Cd on the filtration rate of this mussel were determined in laboratory experiments. Filtration rate was chosen as the endpoint, because it is a sensitive sublethal parameter compared to mortality and it is an important parameter given the ecological role D. polymorpha fulfills. The filtration rate was calculated from the decrease in algal concentration, fed to mussels in aquaria, containing different metal concentrations. The EC50 for Cu (41 microg litre(-1)) was lower than for Cd (388 microg litre(-1)) and Zn (1350 microg litre(-1)). The NOEC(accumulation) for the essential metal Zn was higher than for the essential metal Cu. Cadmium, a non-essential metal, was accumulated at all elevated water concentrations, so the NOEC(accumulation) was the concentration in the control water (<0.2 microg litre(-1)). All (no) effect concentrations found in this study were above the quality criteria set for metal concentrations in Dutch surface water, suggesting that the zebra mussel is sufficiently protected by these quality criteria.

Chronic ecotoxicity of Zn and Pb to the zebra mussel Dreissena polymorpha

“…At the end of the Zn experiment, the filtration rate in the controls was still higher than the filtration rate in the controls of the Pb experiment, which was carried out in the autumn of 1992. In both experiments, the control mussels filtered at a level similar to the higher values reported in the literature (Morton, 1971;Sprung and Rose, 1988), as discussed by Kraak et al (1994).…”

“…was different for each metal and could not be predicted from the results of the shortterm experiments (Bleeker et al, 1992;Kraak et al, 1994). In the present experiments the 48-h EC50 for Zn was determined as 560/2g L -~, lower than the EC50 for Zn found in 1989 (1355/2g L -1, Kraak et al, 1994).…”

“…The water was aerated and always saturated with oxygen. The experimental set-up is discussed in more detail by Kraak et al (1994).…”

“…In the first experiment 0, 40, 100, 400, 1400, and 3000 pg Zn L -1 were tested. 1400 pg Zn L -1 is slightly above the 48-h ECs0 (1355 pg L -1) (Kraak et al, 1994). To get insight in the variation between control treatments, a second control (control-B) was run simultaneously.…”

“…It may be expected that the non-essential metal Pb will be accumulated at every Pb concentration in the water (Bleeker et al, 1992). In contrast, it has been shown that during short-term exposure (48 h) zebra mussels could regulate the body concentration of the essential metal Zn at low external Zn concentrations (up to 191/lg L -l) (Kraak et al, 1994).…”