Effects of atrazine and cyanazine on chlorpyrifos toxicity in chironomus tentans (Diptera: chironomidae)

摘要

Toxicities of two triazine herbicides(atrazine and cyanazine) and an organophosphate insecticide(chlorpyrifos) were evaluated individually and with each herbicide in binary combination with chlorpyrifos using fourth-instar larvae of the aquatic midge, Chironomus tentans. Chlorpyrifos at 0.25 μg/L resulted in an effect in less than 10/100 of midges in48-h acute toxicity bioassays. Neither atrazine nor cyanazine alone at relatively high concentrations(up to 1,000 μg/L) cased significant acute toxicity to C. tentans. However, atrazine and cyanazine caused significant synergistic effects on the toxicity of chlorpyrifos when midges were exposed to mixtures of atrazine or cyanazine(10, 100, 1,000 μg/L) with chlorpyrifos(0.25 μg/L).