The effect of chloride content in water on the toxicity of sodium nitrite for spiny-cheek crayfish (Orconectes limosus Raf.)

Toxicity of sodium nitrite for the spiny-cheek crayfish (Orconectes limosus) was assessed in relation to the concentration of chlorides diluted in water. Results of the tests confirmed a favourable effect of chloride content in water on the tolerance of spiny-cheek crayfish to nitrites. The 96hLC(50) value of 4.8 mg l(-1), 17.7 mg l(-1), 34.7 mg l(-1), 50.5 mg l(-1), 74.4 mg l(-1), and 96.6 mg l(-1) N-NO2- found out in individual tests corresponded, respectively to a chloride content of 11, 40, 100, 200, 300 and 400 mg l(-1) Cl- in diluting water. Linear relationship of the 96hLC(50) values on chloride concentration (y = 0.23 x + 7) was proven statistically (R = 0.995).