Ames testing water samples

Figure 1. Effect of resin type on the mutagenic activity of drinking water concentrates in the Ames test. The sampling, 7000-fold concentration with either XAD-2 or XAD-4/8, DMSO elution (20 mL, neutral fraction), and subsequent mutagenicity testing were as described in Materials and Methods. Similar concentrates of The Hague tap water were used as controls. Each point represents the average of four plates, and 0.50 mL of concentrate corresponds to 3.5 L of water per plate.

Ames Test. Salmonella tryphimurium strains TA98 and TA100 were employed according to the Ames test (15, 16) to determine the mutagenic activity of the various water samples. Each DCM and MeOH extract was tested with and without S9 (microsomal fraction of activated rat liver with Arochlor 1254) activation. For each assay (16 assays per sampling point), the number of revertants per plate was plotted versus increasing volumes of water extracts injected. Slope values from linear regression of the dose-response curves were calculated and then used in the statistical analysis. 

Although many of these techniques will require refinement and validation before they can be used routinely in monitoring, there have been some efforts using effluents as well as ambient water. In one 1977 study, for example. Prein et al. (99) found chromosome breaks in mudminnows exposed to Rhine River water. The same water samples were positive when tested for mutagenic potential with the Ames assay. 

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