Cyanogen chloride

(endorsed 1996)

Guideline

Based on health considerations, the concentration of total cyanogenic compounds in drinking water should not exceed 0.08 mg/L.

General description

Cyanogen chloride is a by-product of chloramination. It can be formed as a by-product of the reaction between organic precursors with hypochlorous acid in the presence of the ammonium ion. Concentrations reported overseas in chloraminated supplies are typically 0.004 mg/L.

Cyanogen chloride may be used commercially in chemical synthesis, and for fumigation.

Typical values in Australian drinking water

No data are available on concentrations of cyanogen chloride in Australian drinking waters.

Limiting formation in drinking water

The presence of cyanogen chloride in drinking water can be minimised by removing naturally occurring organic matter from the source water, by reducing the amount of chloramine added, or by the use of alternative disinfectants.

Measurement

A suitable method for analysis involves extraction from water using the purge and trap technique followed by gas chromatography/mass spectrometry (USEPA Draft Method 524.2 1986). The limit of determination is 0.0003 mg/L.

Health considerations

Cyanogen chloride is highly irritant and very poisonous, as it is rapidly metabolised to cyanide in the body and has similar toxicity.

Effects of ingested cyanogen chloride in humans have not been reported. A concentration of 1 ppm in air causes irritation on inhalation.

Only acute toxicity data are available on the health effects of cyanogen chloride in animals.

No data are available on the carcinogenicity or mutagenicity of cyanogen chloride.

The NHMRC Standing Committee on Toxicity reviewed available toxicity data for cyanogen chloride in 1991. It was considered that data were insufficient to set a no-effect level.

Derivation of guideline

As cyanogen chloride is rapidly converted to cyanide by the body, the guideline value is based on the cyanide value of 0.08 mg/L (see also Fact Sheet on Cyanide).

Reference

USEPA Draft Method 524.2 (1986). Volatile organic compounds in water by purge and trap capillary column gas chromatography/mass spectrometry. United States Environmental Protection Agency, Environmental Monitoring and Support Laboratory (EMSL), Cincinnati, Ohio.