title: A comparison of the sublethal and lethal toxicity of four pesticides in Hyalella azteca and Chironomus dilutus.
abstract: Laboratory toxicity testing is the primary tool used for surface water environmental risk assessment; however, there are critical information gaps regarding the sublethal effects of pesticides. In 10-day exposures, we assessed the lethal and sublethal (motility and growth) toxicities of four commonly used pesticides, bifenthrin, permethrin, cyfluthrin, and chlorpyrifos, on two freshwater invertebrates, Chironomus dilutus and Hyalella azteca. Pyrethroids were more toxic than the organophosphate chlorpyrifos in both species. Bifenthrin was most toxic to H. azteca survival and growth. Cyfluthrin was most toxic to C. dilutus. However, cyfluthrin had the greatest effect on motility on both H. azteca and C. dilutus. The evaluated concentrations of chlorpyrifos did not affect C. dilutus motility or growth, but significantly impacted H. azteca growth. Motility served as the most sensitive endpoint in assessing sublethal effects at low concentrations for both species, while growth was a good indicator of toxicity for all four pesticides for H. azteca. The integration of sublethal endpoints in ambient water monitoring and pesticide regulation efforts could improve identification of low-level pesticide concentrations that may eventually cause negative effects on food webs and community structure in aquatic environments.
authors: Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, One Shields Avenue, Davis, CA, 95616, USA.
authors: Simone
authors: S
authors: Hasenbein
authors: Richard E
authors: RE
authors: Connon
authors: Sharon P
authors: SP
authors: Lawler
authors: Juergen
authors: J
authors: Geist
mesh_terms: D033304:Amphipoda / Q000187:drug effects / Q000254:growth & development; D000818:Animals; D002683:Chironomidae / Q000187:drug effects / Q000254:growth & development; D004390:Chlorpyrifos / Q000633:toxicity*; D007928:Lethal Dose 50; D009043:Motor Activity / Q000187:drug effects; D009570:Nitriles / Q000633:toxicity*; D026023:Permethrin / Q000633:toxicity*; D010575:Pesticides / Q000633:toxicity*; D011722:Pyrethrins / Q000633:toxicity*; D018570:Risk Assessment; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D060753:Water Quality
chemical_list: D009570:Nitriles; D010575:Pesticides; D011722:Pyrethrins; D014874:Water Pollutants, Chemical; D026023:Permethrin; C099952:bifenthrin; D004390:Chlorpyrifos; C052570:cyfluthrin