Studies On The Toxic Effect Of Metal Ions And Pesticides On Rotifer Brachionus Calyciflorus

The toxic effects of metal ions and pesticides on Rotifer Brachionus calyciflorus(BC) were studied in this paper. Brief results are followed:(1) The 24h LC₅0 of Cu²+, Zn²+, Cd²+ and Pb²+to BC were 0.060, 1.69, 1.49 and 20.89mg/L respectively. The 48h LC₅0 were 0.024, 0.565, 0.526 and 13.94 mg/L. The 96h LC₅0 were 0.015, 0.260, 0.315 and 1.353 mg/L. In the solution of Cu²+, Zn²+, Cd²+ and Pb²+, the survivorship, reproduction rate, basic reproduction rate and intrinsic rate of increase were quickly decreased, while the number of resting eggs and the percentage of mictic female produced were greatly increased.In the joint toxicity sdudy, synergistic effects have been found in paired mixtures with the exception of Zn-Cd which acts antagonistically. When the organisms were exposed to equitoxic mixtures of three metal ions, synergistic action effects have been found with the exception of Cu-Zn-Cd, Cu-Pb-Cd and Zn-Cd-Pb which acts antagonistically. When the organisms were exposed to the mixtures of four metal ions, the joint toxicity was synergistic.The toxic effects of metal ions were changed with the temperature increasing from 20 癈 to 25 C and pH varying between 3.5 and 11.5. Compare with the temperature, toxic effects of metal ions were changed more differently when pH varied.(2) The 24h LC50 of cypermethrin, avermection-phoxim mixture and trichlorphon to BC were 0.292, 0.607 and 344.6mg/L respectively. The 48h LC50 were 0.228, 0.291 and 264.2 mg/L. In the solution of cypermethrin and avermection-phoxim mixture, the survivorship and reproduction rate were quickly decreased, while the toxicity effects of trichlorphon were not distinct.