title: Comparative aquatic toxicity of the pyrethroid insecticide lambda-cyhalothrin and its resolved isomer gamma-cyhalothrin.
abstract: In this review we compare the sensitivity of a range of aquatic invertebrate and fish species to gamma-cyhalothrin (GCH), the insecticidally active enantiomer of the synthetic pyrethroid lambda-cyhalothrin (LCH), in single-species laboratory tests and outdoor multi-species ecosystem tests. Species sensitivity distribution curves for GCH gave median HC(5) values of 0.47 ng/L for invertebrates, and 23.7 ng/L for fish, while curves for LCH gave median HC(5) values of 1.05 ng/L and 40.9 ng/L for invertebrates and fish, respectively. A model ecosystem test with GCH gave a community-level no observed effect concentration (NOEC(community)) of 5 ng/L, while model ecosystem tests with LCH gave a NOEC(community) of 10 ng/L. These comparisons between GCH and LCH indicate that the single active enantiomer causes effects at approximately one-half the concentration at which the racemate causes similar effects.
authors.affiliation: Compliance Services International, Rochester, MA, 02770, USA. jgiddings@ComplianceServices.com
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Giddings
authors.forename: Ian
authors.initials: I
authors.lastname: Barber
authors.forename: William
authors.initials: W
authors.lastname: Warren-Hicks
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D056890:Eukaryota / Q000187:drug effects*; D005399:Fishes / Q000378:metabolism*; D007306:Insecticides / Q000737:chemistry / Q000633:toxicity*; D007448:Invertebrates / Q000187:drug effects*; D009570:Nitriles / Q000737:chemistry / Q000633:toxicity*; D011722:Pyrethrins / Q000737:chemistry / Q000633:toxicity*; D013045:Species Specificity; D013237:Stereoisomerism
chemical_list: D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C037304:cyhalothrin