Acute toxicity of Butachlor to Caspian Kutum ( Rutilus frisii Kutum Kamensky, 1991)

Abstract

Herbicides are used to control weeds and are usuall y targeted to processes and target sites that are s pecific to plants. Butachlor is an herbicide of the acetanilide class, which is used widely in agricultural fields. At th e present study, lethal concentration (LC 50 ) of butachlor was calculated for Rutilus frisii Kutum . Samples weighted 4 ± 1 (mean ± SD) gr. The experiment were carried out in static condition and based on instructions of Organisation for Economic Co-operation and Development (O.E.C.D) in 4 days under controlled water physicochemical factors with pH was 8-8.3, BOD 690 mg/l total hardness 210 mgCaCo 3 and temperature was 17 ± 0.1 °C. All fishes were ac climatized in 60◊55◊30 cm aquarium for 10 days. Treated aquariums with concentration ranges 0.11, 0 .22, 0.33, 1, 1.66, 2.33, 3.33, 6.66, 13.33, 16.66 mg/l of butachlor and control group (no toxic concentration) were perform ed. LC 1, LC 10 , LC 30 , LC 50 , LC 70 , LC 90 and LC 99 were calculated for 24, 48, 72 and 96 hours. LC50 96h butachlor for R. frisii Kutum was obtained 0.258 ppm. These findings suggest tha t butachlor is moderately toxic and moderately irritating for this species. Clinical symptoms including irregular pro trusion of the eyes and irregular swimming were observed.