A community-based approach to analyzing the ecotoxicity of nitrofurazone using periphytic protozoa.

The ecotoxicity of nitrofurazone was analyzed based on a community-based approach using periphytic protozoa. Median lethal concentrations (LC) within an exposure time of 30 min were determined by an acute toxicity test at 0, 1.5, 3, 6 and 12 mg ml nitrofurazone. Toxicity curve tests demonstrated a decreasing trend with increasing exposure time and was well fitted to the toxicity equation LC = 32.85e (t = exposure time; R = 0.91; P < 0.05). Median inhibition concentrations (IC) for periphytic protozoan growth rates were obtained by chronic tests at 0, 1, 2, 4 and 8 mg ml nitrofurazone within 10 days exposure and were well fitted to the equation r = 0.3686e (C is the concentration of nitrofurazone; R = 0.92 and P < 0.05). These findings suggest that the LC and IC values of nitrofurazone can be predicted for any exposure time using periphytic protozoan communities as a bioassay model.