ABSTRACT
Concerns over the toxicity of cyanide to aquatic organisms have resulted from the use and discharge of cyanide compounds from sewage treatment plants, industrial processes, and from extraction of gold or silver from natural ores [Chapter 3; 1]. Free hydrogen cyanide (HCN) concentrations can occur in surface waters from 0.005 to several mg HCN/l [1], and thus, may reach concentrations that are sublethal or lethal to both freshwater and marine organisms under some circumstances.
