Examination of a Drinking-Water Supply for Mutagenicity

Abstract

The results of an Ames test survey of the drinking-water of the administrative capital of South Africa showed the widespread presence of at least one unidentified, frameshift, weakly polar mutagen, which needed no activation by rat liver enzymes. This mutagenicity was found to be perpetual in the water from at least one sampling point and probably originated from the same source. Extraction of the mutagen(s) from the water was achieved by adsorption onto XAD-2 resin, followed by desorption with acetone. No base-pair substitution mutagen could be detected. Optical density, pH and electrical conductivity determinations showed that the relative contribution of surface and groundwater to the drinking-water at the different sampling points remained fairly constant during the survey. No correlation could be found between mutagenicity and the volatile halogenated organic compounds as well as the polynuclear aromatic hydrocarbons in the waters. The survey was organized as part of an identification process, so that the results could be used not only to establish whether there was a need for further identification of the mutagen(s), but to furnish some of the information needed for their successful isolation.