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Some experiments on the toxicity of complex cyanides to fish

Journal Article · · Sewage Ind. Wastes; (United States)
OSTI ID:6884264
The toxicity to minnows, Pimephales promelas, of mixed solutions of sodium cyanide and sulfates of heavy metals, diluted with synthetic soft water, was evaluated in order to learn the degree of toxicity, to fish, of complex cyanides found in industrial wastes. The potentials of complex formation as a waste treatment method thus were explored also. The zinc cyanide and cadmium cyanide complexes, proved exceedingly toxic. Synergism of the metallic ions and cyanide is indicated. Free cyanide combines with nickel ions, to form a fairly stable complex, even when concentrations are low. Marked reduction of the toxicity of the cyanide, and also of the nickel, occurred as a result of this combination. However, dissociation of the harmless complex nickelocyanide ions is negligible in dilute solutions only when they are alkaline (pH about 8.0 or higher). The toxicity of waste waters containing free ionic copper can be markedly reduced by complexing the copper with cyanide. Extremely toxic mixtures of copper and zinc, which are synergistic metals, likewise can be detoxified by the addition of free cyanide, which combines with the copper.
OSTI ID:
6884264
Journal Information:
Sewage Ind. Wastes; (United States), Journal Name: Sewage Ind. Wastes; (United States) Vol. 28; ISSN SIWAA
Country of Publication:
United States
Language:
English