5.1 Cyanide and hydrogen cyanide are highly toxic. Regulations have been established to require the monitoring of cyanide in industrial and domestic wastes and surface waters.³

5.2 This test method is applicable for natural waters, industrial wastewaters and effluents.

1.1 This test method is used to determine the concentration of total cyanide in an aqueous wastewater or effluent. The method detects the cyanides that are free (HCN and CN^-) and strong-metal-cyanide complexes that dissociate and release free cyanide when refluxed under strongly acidic conditions.

1.2 This method may not be applicable to process solutions from precious metals mining operations.

1.3 This procedure is applicable over a range of approximately 2 to 400 μg/L (parts per billion) total cyanide. Higher concentrations can be measured with sample dilution or lower injection volume.

1.4 The determinative step of this method utilizes flow injection with amperometric detection based on Test Method D6888. Prior to analysis, samples must be distilled with a micro-distillation apparatus described in this test method or with a suitable cyanide distillation apparatus specified in Test Methods D2036.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Note 2 and Section 9.