respectively and median lethal concentration (LC50) of lead to Caspian sea kutum (R. frisii kutum) for 24, 48, 72 and 96 h of exposure as 315.841, 298.456, 281.419 and 268.065 ppm,
respectively and median lethalconcentration (LC50) of lead to Caspian sea kutum (R. frisii kutum) for 24, 48, 72 and 96 h of exposure as315.841, 298.456, 281.419 and 268.065 ppm,