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(M/MF138) Effects of binary mixtures of zinc, copper and cadmium on food consumption in woodlice. Zidar, Primoz1, Drobne, Damjana1, ¿trus, Jasna 1, 1 ABSTRACT- The use of toxicity tests in which each metal is tested separately is inadequate for assessing the potential risk of complex mixtures of metals for soil ecosystems. In our study single and joint toxic effects of zinc, cadmium and copper were investigated in terrestrial isopod Porcellio scaber (Crustacea). The juvenile animals were fed with hazel leaves containing different concentrations of single or two different metals during three weeks. Sublethal toxicity was judged by effects on food consumption and assimilation of metals. Observed effects of metal mixtures were compared with effects expected from simple similar action model (concentration addition), by recalculation of metal concentrations in toxic units. The reduction of food consumption was metal concentration dependent. For zinc, copper and cadmium 50% effective concentrations (EC50) values were 2260, 1190 and 232 Key words: mixture toxicity, metals, crustaceans, food consumption |
g/g dry food, respectively. The effects of binary mixtures of zinc and cadmium on food consumption in woodlice were less than concentration additive (EC50 significantly greater than 1.0 toxic unit). Zinc decreased the cadmium assimilation in mixture with cadmium, however, cadmium had no effect on the zinc assimilation. The effects of binary mixtures of zinc and copper or cadmium and copper were concentration additive. At high concentrations zinc decreased the copper assimilation. Considering zinc - cadmium interactions and the ratio of zinc and cadmium concentrations in the environment, we may conclude that woodlice in industrially polluted environment are more affected by zinc than by cadmium, although cadmium is much more toxic than zinc.