Formalin Toxicity to Caspian roach, Rutilus rutilus caspicus Fry

Formalin is a common disinfectant and therapeutic agent in fisheries-related activities. Considering large variation in susceptibility of different species to formalin toxicity, it is necessary to determine its toxicity and safety margins in different species, separately. Therefore, to investigate formalin acute toxicity and safety margins on Caspian roach, an experiment was conducted in ۱g Caspian roachs Rutilus rutilus caspicus. Fish were exposed to ۰, ۳۰, ۴۰, ۴۵, ۵۰, ۵۵, ۶۰, ۷۰, ۱۰۰, ۱۵۰, ۲۰۰, ۲۵۰, ۳۰۰ and ۴۰۰ ppm formalin and mortality was recorded after ۰.۵, ۱, ۱۲, ۲۴, ۴۸, ۷۲ and ۹۶h. ۰.۵-۹۶ h LC۵۰ values were ۴۹-۲۴۶ ppm. The lowest observed effect concentrations (LOEC) were found to be ۴۰-۱۵۰ ppm at different periods. No observed effect concentrations (NOEC) were ۳۰-۱۰۰ ppm at different periods. According to regression model for NOEC versus time, concentrations of ۸۸.۴, ۸۰.۳, ۵۱.۲ and ۴۰.۱ ppm are suggested as the maximum concentrations for ۰.۵, ۱, ۱۲ and ۲۴ h bath treatment, respectively. Results showed the recommendations for formalin safety in the literatures are not applicable and valid for Caspian roach. Such differences could be due to species or experimental differences which should be taken into account before treating.

کلیدواژه ها:

Caspian roach ، Disinfectant ، LOEC ، NOEC ، toxicity