Acute toxicities of five synthetic pyrethroid insecticides to Daphnia magna and Ceriodaphnia dubia

The acute toxicities of four recently developed pyrethroid insecticides (bifenthrin, cyfluthrin, lambda cyhalothrin and tralomethrin) were experimentally compared to the acute toxicity of a first generation pyrethroid (permethrin), in static-flow, 48-h bioassays with Daphnia magna and Ceriodaphnia dubia. The four new generation pyrethroids exhibited greater toxicity, with LC50s ranging from 0.15 to 1.04 μg/L for D. magna and 0.07 to 0.30 μg/L for C. dubia, in comparison to permethrin with LC50s of 1.25 μg/L for D. magna and 0.55 μg/L for C. dubia. Tralomethrin and cyfluthrin were most toxic to D. magna, with LC50s of 0.15 and 0.17 μg/L, respectively. C. dubia exhibited the greatest sensitivity to the pyrethroids, with an LC50 of 0.07 μg/L for bifenthrin. C. dubia was equally or more sensitive than D. magna to all of the insecticides.