Mutagenic activity drinking water

Sodium chlorite is not Hsted by the USEPA or any regulatory authority as a carcinogen. Studies conducted ia mice and rats did not show an increase in tumors in animals exposed to sodium chlorite in thek drinking water. Sodium chlorite has been found to have mutagenic activity in some in vitro test systems such as the Ames Salmonella reverse mutation assay without the presence of metaboHc activators. The significance of these test results in regard to human health is not clear because of the oxidizing effects of the chlorite ion (149). 

Simmon VF, Tardiff RG. 1978. The mutagenic activity of halogenated compounds found in chlorinated drinking water. In Water chlorination Environmental impact and health effects. Vol. 2. Ann Arbor, Ml Ann Arbor Science, 417-431. 

Simmon VF, Kauhanen K, Tardiff RG. 1977. Mutagenic activity of chemicals identified in drinking water. Dev Toxicol Environ Sci 1 249-258. 

Wright JM, Schwartz J, Vartiainen T, Maki-Paakkanen J, Altshul L, Harrington JJ, Dockery DW (2002) 3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-fiu-anone (MX) and mutagenic activity in Massachusetts drinking water. Environ Health Perspect 110(2) 157-164... 

Zoeteman BCJ, Hmbec J, de Greef E, et al. 1982. Mutagenic activity associated with by-products of drinking water disinfection by chlorine, chlorine dioxide, ozone and UV-irradiation. Environ Health Perspect 46 197-205. 

Simmon, V.F., Kauhanen, K. Tardiff, R.G. (1977) Mutagenic activity of chemicals identified in drinking water. In Scott, D., Bridges, B.A. Sobels. F.H.. eds. Progress in Genetic Toxicology, Amsterdam. Elsevier/North-Holland, pp. 249-258... 

Figure 5. Direct-acting mutagenic activity of HPLC fractions (1-4, Figure 4) obtained by sequential step elution of residue organics isolated from finished drinking water I. Af/X indicates the mutagenic activity measure for an aliquot of residue organics proportionately reconstituted from the separate fractions Sl/Af is the arithmetic sum of the net revertant colonies for each dose for...

Considerable information of a general nature is available for uncontaminated water subject to the production of disinfection byproducts. The mutagens produced by drinking water chlorination appear to be numerous, but they exist either at low levels or are of low potency. For both the unresolved mixtures and for the few mutagenic compounds thus far identified, activity is readily reduced or destroyed by treatment with alkali or 4-nitrothiophenol and may be removed by GAC treatment. From water sources subject both to mutagen formation via disinfection and to periodic contamination by toxic chemicals, experimental full-scale GAC treatment systems have provided mutagen-free water. 

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.

Figure 3. Effect of heating on the activity of a mutagenic drinking water concentrate. A mutagenic XAD-4/8 acetone concentrate (neutral fraction) was heated to 250 °C. The total heating time was 1 h. After this period, the organic residue was dissolved in acetone and retested in the Salmonella...

Figure 6. Fractionation of a mutagenic drinking water concentrate with Sephadex LH20. On a Sephadex LH20 column, 1.6 mL of a drinking water concentrate (IX 106-fold concentrated, neutral fraction) was separated by using stepwise isopropyl alcohol (ISOP) and dioxane/water (D/W) elution as described in Material and Methods. Fractions were pooled as indicated. After reconcentration the fractions were assayed for mutagenic activity in the Salmonella mutagenicity test and CHO cells (Table I).

Figure 8. Mutagenic activity of a fractionated LH20 drinking water concentrate (neutral fraction) as detected with nitroreductase-deficient bacterial strains. LH20 fractionated drinking water concentrates were tested in the Salmonella mutagenicity test as described in Materials and Methods. Each point represents the average value of three plates.

Figure 9. Distribution of halogenated hydrocarbons and mutagenic activity in HPLC fractions of a drinking water concentrate (neutral fraction). HPLC fractions obtained by linear-gradient HPLC analysis (H2O-C2H3N) were tested for mutagenic activity in the Salmonella mutagenicity test (TA98) and assayed for halogenated hydrocarbon content as described in Materials...

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