title: Toxicity of three pesticides individually and in mixture to larval grass shrimp (Palaemonetes pugio).
abstract: This study examined the toxicity of three pesticides, singly and in mixture, to grass shrimp (Palaemonetes pugio) larvae. The pesticides included atrazine, an herbicide used on turf grass and field crops; fipronil, a persistent insecticide used against termites and fire ants; and imidacloprid, a systemic insecticide used in agricultural and home products. Fipronil was the most toxic to shrimp larvae with a 96-h LC50 of 0.68microg/L (95% CI 0.57-0.79microg/L). Shrimp larvae were less sensitive to imidacloprid with a 96-h LC50 of 308.8microg/L (95% CI 273.6-348.6microg/L). Atrazine was non-toxic to shrimp larvae at concentrations up to 10,000microg/L. In mixtures, fipronil plus atrazine and imidacloprid plus atrazine had no change in toxicity compared to fipronil and imidacloprid tested singly. Similarly, a fipronil/imidacloprid mixture did not show greater than additive toxicity. However, when atrazine was added to the fipronil/imidacloprid mix, greater than additive toxicity occurred.
authors.affiliation: NOAA, National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Road, Charleston, SC 29412, USA. pete.key@noaa.gov
authors.forename: Peter
authors.initials: P
authors.lastname: Key
authors.forename: Katy
authors.initials: K
authors.lastname: Chung
authors.forename: Tom
authors.initials: T
authors.lastname: Siewicki
authors.forename: Mike
authors.initials: M
authors.lastname: Fulton
mesh_terms: D000818:Animals; D001280:Atrazine / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D007093:Imidazoles / Q000633:toxicity*; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D007928:Lethal Dose 50; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000633:toxicity*; D033541:Palaemonidae / Q000187:drug effects* / Q000254:growth & development; D010575:Pesticides / Q000633:toxicity*; D011720:Pyrazoles / Q000633:toxicity*; D013997:Time Factors; D023382:Toxicity Tests, Acute
chemical_list: D007093:Imidazoles; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010575:Pesticides; D011720:Pyrazoles; C082359:imidacloprid; C082360:fipronil; D001280:Atrazine