Total Cyanide Analysis Of NPDES Wastewater Samples By ASTM D 7511-09e2

The Federal Water Pollution Control Act Amendments of 1972 directed the U.S. EPA to complete a list of toxic pollutants in water for which effluent standards were subsequently proposed  Cyanide was included on the list of toxic pollutants.

The first generation of U.S. EPA cyanide analysis methods from the 1970s employ an acid distillation  sample pretreatment step to dissociate cyanide from metal-cyanide complexes and separate cyanide from the matrix. Acid distillation is known to cause either negative or positive analytical biases depending upon the composition of the sample matrix being tested. In fact, the U. S. EPA Solutions to Analytical Chemistry Problems with Clean Water and Methods  (“Pumpkin Guide”) notes; “Next to oil and grease, cyanide is the pollutant for which the most matrix interferences have been reported.” Table 1 provides a summary of cyanide analysis interferences  associated with acid distillation of samples.

ASTM D 7511-09 e2  defines a method for the determination of total cyanide in various types of water (such as ground, municipal waste, industrial effluent, leachate, and surface water). This automated method is applicable to a mass concentration range of 3–500 μg/L CN, however, higher concentrations can be determined by either performing dilutions or changing the operating conditions.