title: Impact of pretilachlor herbicide and pyridaphenthion insecticide on aquatic organisms in model streams.
abstract: To detect the impact of pesticides on aquatic organisms, model streams (3m wide, 20 m long) were established in paddy field in Japan. More than 100 species of aquatic organisms were generated in the model streams. Field tests with pretilachlor herbicide and pyridaphenthion insecticide were carried out in the streams for 3 yr (2001-2003). Exposure of pretilachlor (max. 0.382 mg/L) showed little density changes in algae with a Bray-Curtis percent similarity in the range 81.6-93.3% for algae. Exposure to high concentrations (>0.1mg/L) of pyridaphenthion produced visible density reductions in Cladocera zooplankton species. Reduction of individual aquatic insects in the model streams by pyridaphenthion caused an increase of chlorophyll a greater than that of the control streams. The pesticides used showed no substantial differences in the ecosystems of model streams exposed to maximum environmental concentrations (e.g., 0.01 mg/L) detected in real rivers.
authors.affiliation: Research Institute of Japan Plant Protection Association, Kessoku 535, Ushiku, Ibaraki 300-1212, Japan. ytakasan@jppa.or.jp
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Houjyo
authors.forename: Toshiki
authors.initials: T
authors.lastname: Kohjimoto
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takagi
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Mori
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Muraoka
authors.forename: Hirochika
authors.initials: H
authors.lastname: Annoh
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Ogiyama
authors.forename: Yuki
authors.initials: Y
authors.lastname: Funaki
authors.forename: Kaoru
authors.initials: K
authors.lastname: Tanaka
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Wada
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Fujita
mesh_terms: D000083:Acetanilides / Q000633:toxicity*; D000818:Animals; D004784:Environmental Monitoring / Q000379:methods; D056890:Eukaryota / Q000187:drug effects; D006540:Herbicides / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D007564:Japan; D008962:Models, Theoretical; D009946:Organothiophosphorus Compounds / Q000633:toxicity*; D012275:Oryza / Q000254:growth & development; D010839:Phytoplankton / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015048:Zooplankton / Q000187:drug effects
chemical_list: D000083:Acetanilides; D006540:Herbicides; D007306:Insecticides; D009946:Organothiophosphorus Compounds; D014874:Water Pollutants, Chemical; C118050:pretilachlor; C010418:pyridafenthion