title: Acute toxicity of triazine pesticides to juvenile signal crayfish (Pacifastacus leniusculus).
abstract: OBJECTIVE
  Crustacea are at high risk of toxic effects of agricultural pesticides. Currently, many questions regarding the toxicity of triazine herbicides to crayfish remain unresolved. The aim of this research was to evaluate the acute toxicity of atrazine, hexazinone, metribuzine, prometryne, simazine, and terbutryne to juvenile signal crayfish (Pacifastacus leniusculus).
  
  
  METHODS
  Acute toxicity tests were performed in accordance with standardized guidelines for testing of chemicals, OECD no. 203, using a semistatic test system. Signal crayfish juveniles (n=672) of 49.0-81.5 mg weight and 12.8-16.0 mm total length were used for the bioassay. Mortalities were recorded daily to 96 h. Each pesticide was tested at concentrations of 1, 10, 40, 70, and 100 mg.l-1. Percent mortalities were analyzed by linear regression, and median lethal concentration (LC50) values were computed using probit analysis EKO-TOX 5.2 software.
  
  
  RESULTS
  96hLC50 values for juvenile signal crayfish were 12.1 mg.l-1 for atrazine, 13.9 mg.l-1 for terbutryne, 14.4 mg.l-1 for prometryne, 19.5 mg.l-1 for hexazinone, 30.6 mg.l-1 for metribuzine, and 77.9 mg.l-1 for simazine. Atrazine showed the greatest toxicity to signal crayfish.
  
  
  CONCLUSIONS
  The present study demonstrated that triazines are toxic to signal crayfish. Signal crayfish is more sensitive than the fish for atrazine, hexazine, metribuzine, and for these triazines signal crayfish can be used as a bio-indicator of environmental contamination.
authors.affiliation: University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, V, Czech Republic. velisek@frov.jcu.cz.
authors.forename: Jozef
authors.initials: J
authors.lastname: Velisek
authors.affiliation: University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, V, Czech Republic.
authors.forename: Antonin
authors.initials: A
authors.lastname: Kouba
authors.affiliation: University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, V, Czech Republic.
authors.forename: Alzbeta
authors.initials: A
authors.lastname: Stara
mesh_terms: D000818:Animals; D003400:Astacoidea / Q000187:drug effects* / Q000502:physiology; D001522:Behavior, Animal / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D009043:Motor Activity / Q000187:drug effects; D010575:Pesticides / Q000633:toxicity*; D023382:Toxicity Tests, Acute; D014227:Triazines / Q000633:toxicity*
chemical_list: D010575:Pesticides; D014227:Triazines