Chloroketones

1,1-dichloropropanone (dichloroacetone); 1,3-dichloropropanone; 1,1,1-trichloropropanone (trichloroacetone); 1,1,3-trichloropropanone (endorsed 1996)

Guideline

Data are inadequate to set guideline values for chloroketones in drinking water.

General description

The chloroketones are produced in drinking water as by-products of the reaction between naturally occurring organic matter and chlorine. No data are available on other sources or uses for these compounds.

Concentrations of chloroketones in drinking water reported overseas are very low and are estimated at less than 0.01 mg/L.

Typical values in Australian drinking water

In major Australian reticulated supplies 1,1,1-trichloropropanone has been recorded in concentrations up to 0.02 mg/L, but it is usually below the limit of determination of 0.0005 mg/L. No data are available for other chloroketones.

Limiting formation in drinking water

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

Measurement

A solvent extraction procedure is suitable for the analysis of chloroketones (USEPA Draft Method 551 1990). Sodium chloride is added to the sample and the chloroketones extracted using methyl tert-butyl ether. The extracts are then analysed using gas chromatography with an electron capture detector. Limits of determination are less than 0.0005 mg/L.

Health considerations

No data are available on absorption from the gastrointestinal tract, metabolism or health effects in humans.

Acute oral toxicity studies in mice using 1,1-dichloropropanone and 1,3-dichloropropanone have found no toxic effects with single doses of 130 mg/kg and 20 mg/kg respectively. No long-term toxicity studies have been reported.

Both 1,1-dichloropropanone and 1,3-dichloropropanone were direct-acting mutagens in tests with bacteria. There was some evidence that 1,3-dichloropranone initiated skin tumours in mice when applied at 50 mg/kg body weight per day for two weeks. There was no evidence that either 1,1-dichloropropanone or 1,1,1-trichloropropanone acted in this way.

The NHMRC Standing Committee on Toxicity reviewed the available data for chloroketones in 1991. It was concluded that data were insufficient to set no-effect levels for these compounds.

Reference

USEPA Draft Method 551, (1990). Determination of chlorination disinfection by-products and chlorinated solvents in drinking water by liquid–liquid extraction and gas chromatography with electron capture detection. United States Environmental Protection Agency, Environmental Monitoring and Support Laboratory (EMSL), Cincinnati, Ohio.