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

Abstract

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 96hLC50 values on chloride concentration (y = 0.23 x+ 7) was proven statistically (R = 0.995).