Acute toxicity to zebrafish of two organophosphates and four pyrethroids and their binary mixtures.
BACKGROUND
Environmental pollutants, including metals, pesticides and other organics, pose serious risks to many aquatic organisms. The acute toxicities to zebrafish (Brachydanio rerio Hamilton & Buchanan) were determined for two organophosphorus insecticides, four pyrethroid insecticides and 50:50 binary mixtures.


RESULTS
At 24, 48, 72 and 96 h after treatment, LC(50) of permethrin, tetramethrin, bifenthrin, etofenprox, dichlorvos and phoxim to zebrafish were 0.0052-0.0025, 0.0782-0.0460, 0.0065-0.0032, 0.0969-0.0791, 51.3-13.0 and 1.28-0.469 mg L(-1) respectively. LC(50) of permethrin + dichlorvos, permethrin + phoxim, tetramethrin + dichlorvos, tetramethrin + phoxim, bifenthrin + dichlorvos, bifenthrin + phoxim, etofenprox + dichlorvos and etofenprox + phoxim were 0.0082-0.0046, 0.0078-0.0042, 0.264-0.124, 0.141-0.121, 0.0251-0.0154, 0.0154-0.0087, 0.396-0.217 and 0.213-0.0391 mg L(-1).


CONCLUSIONS
Toxicity levels of all pyrethroid insecticides to the zebrafish were high or very high. The organophosphate dichlorvos showed low toxicity, but phoxim showed high or intermediate toxicities to zebrafish, and the toxicities of binary mixtures of permethrin and dichlorvos or phoxim, bifenthrin and dichlorvos or phoxim and etofenprox and phoxim (48, 72 and 96 h exposure) were very high. The toxicities of binary mixtures of tetramethrin and dichlorvos or phoxim, etofenprox and dichlorvos and etofenprox and phoxim (24 h exposure) were high.
Zhang
Zhi-Yong
ZY
Institute of Food Safety Research and Inspection, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China.
Yu
Xiang-Yang
XY
Wang
Dong-Lan
DL
Yan
Hai-Juan
HJ
Liu
Xian-Jin
XJ
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D004347:Drug Interactions; D007306:Insecticides; D007928:Lethal Dose 50; D010755:Organophosphates / Q000633:toxicity*; D011722:Pyrethrins / Q000633:toxicity*; D023382:Toxicity Tests, Acute; D015027:Zebrafish
D007306:Insecticides; D010755:Organophosphates; D011722:Pyrethrins