Risk assessment of lambda-cyhalothrin on aquatic organisms in paddy field in China.
This study was carried out to assess the risk of lambda-cyhalothrin to aquatic organisms used in paddy field, and to provide assistance in the ecological risk management of lambda-cyhalothrin. The acute toxicities of five individual formulations of lambda-cyhalothrin to four aquatic species were investigated in the laboratory, as well as in a simulated paddy field-pond ecosystem, and the results implicated that lambda-cyhalothrin is highly toxic to fish, and to a greater extent to shrimp. There were differences in the toxicities to each aquatic organisms among different formulations. lambda-Cyhalothrin degraded rapidly in the environment, with half-lives of different formulations in paddy field water (0.23-0.53 days), pond water (0.38-0.63 days), and paddy field soil (0.96-7.35 days), respectively. The water overflow from the paddy field following a simulated rainstorm 12h after application of lambda-cyhalothrin did not cause injury to fish, clam or crab, but was severely hazardous to shrimp. Additionally, no injury to shrimp was found when simulated overflow occurred 4 days after application. These results suggest that the environmental risk of lambda-cyhalothrin to aquatic organisms can be reduced by (1) developing a relatively safe formulation such as a suspension concentrate, and/or (2) controlling the drainage time of the paddy field.
Gu
Bao G
BG
College of Agronomy and Biotechnology, China Agricultural University, Beijing 100094, China.
Wang
Hui M
HM
Chen
William L
WL
Cai
Dao J
DJ
Shan
Zheng J
ZJ
D000818:Animals; D002681:China; D003445:Crustacea; D005618:Fresh Water / Q000737:chemistry; D009570:Nitriles / Q000009:adverse effects*; D010575:Pesticides / Q000009:adverse effects; D011722:Pyrethrins / Q000009:adverse effects*; D018675:Toxicity Tests; D014874:Water Pollutants, Chemical / Q000009:adverse effects*; D015027:Zebrafish
D009570:Nitriles; D010575:Pesticides; D011722:Pyrethrins; D014874:Water Pollutants, Chemical; C037304:cyhalothrin