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Chronic toxicity of 6 neonicotinoid insecticides to Chironomus dilutus and Neocloeon triangulifer
Author(s) -
Raby Melanie,
Zhao Xiaoming,
Hao Chunyan,
Poirier David G.,
Sibley Paul K.
Publication year - 2018
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.4234
Subject(s) - clothianidin , thiamethoxam , neonicotinoid , thiacloprid , acetamiprid , imidacloprid , toxicology , pesticide , chronic toxicity , environmental chemistry , biology , chemistry , toxicity , ecology , organic chemistry
Neonicotinoid insecticides are frequently detected in surface waters near agricultural areas, leading to a potential for chronic exposure to sensitive aquatic species. The midge Chironomus dilutus and the mayfly Neocloeon triangulifer have been shown to be acutely sensitive to neonicotinoids. Previous studies have established chronic effects of some neonicotinoids on C. dilutus , but reproduction has not been studied. Toxic effects have not been assessed using N. triangulifer . We present the results of chronic, static‐renewal tests for 6 neonicotinoids (acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, and thiamethoxam) with C. dilutus (≤56‐d in length) and N. triangulifer (≤32‐d in length). Emergence was generally the most sensitive endpoint for both species across all neonicotinoids. Effect concentrations, 10% (EC10s; emergence) were 0.03 to 1.1 μg L −1 for acetamiprid, clothianidin, imidacloprid, and thiacloprid. Dinotefuran and thiamethoxam were less potent, with EC10s ( C. dilutus ) or median effect concentrations (EC50s; N. triangulifer ) of 2.2 to 11.2 μg L −1 . Hazard was assessed through comparison of neonicotinoid environmental concentrations from agricultural surface waters in Ontario (Canada) with either the 5th percentile hazard concentration (for imidacloprid) or species‐specific EC10s from the present study (for all remaining neonicotinoids). The resulting hazard quotients (HQs) indicated little to no hazard (HQ <1) in terms of chronic toxicity for acetamiprid, dinotefuran, thiacloprid, or thiamethoxam. A moderate hazard (HQ >1) was found for emergence of N. triangulifer for clothianidin, and a high hazard (HQ = 74) was found for imidacloprid. Environ Toxicol Chem 2018;37:2727–2739. © 2018 SETAC