Techniques for the Fractionation and Identification of Mutagens Produced by Water Treatment Chlorination

Abstract

Byproducts of the chlorination of treated water, humic acids, and amino acids were shown to be mutagenic to Salmonella typhimurium strain TA100 in the fluctuation test. A two-stage fractionation procedure, using high-performance liquid chromatography (HPLC) combined with the fluctuation test, was developed. Several mutagenic fractions were obtained from an XAD extract of chlorinated water; this result indicated the presence of several mutagens. The mutagenic activities of extracts of different chlorinated amino acids were compared. The products identified by capillary gas chromatography-mass spectrometry did not account for the mutagenic activity. However, additional products were detected by HPLC with UV detection in extracts of chlorinated tyrosine and phenylalanine. (1-3). Compounds that are widely distributed in the aquatic environment, such as humic substances and amino acids, have been found to react with chlorine to produce mutagenic compounds (4, 5). These compounds may account for at least some of the mutagenic activity of extracts of drinking waters. CONCENTRATED EXTRACTS OF MANY DRINKING WATERS in the United Kingdom and elsewhere are mutagenic as observed in bacterial assaysBecause a good correlation is found between mutagenicity (as detected in bacterial assays such as the Ames test) and carcinogenicity (as observed in laboratory animal tests) (6), mutagenicity detected in water extracts indicates the possibility of a carcinogenic hazard.

Reactions of Aqueous Chlorine and Chlorine Dioxide with Tryptophan, N‐Methyltryptophan, and 3‐Indolelactic Acid: Kinetic and Mutagenicity Studies

“…The binding of the sample with the S9 mix might have decreased the quantity of test sample available for bacterial mutagenesis or detoxification via the mixed function oxidase system in the S9 might have contributed to the reduced number of revertants. These results were in agreement with other published reports (Horth et al, 1987;Sussmuth, 1982;Tan et al, 1987b).…”

“…The chlorination of other amino acids have been shown to produce similar mutagenic effects (Horth et al, 1987;Sussmuth, 1982). This finding is important to the food industry, especially in the meat and seafood processing areas.…”

“…Resin adsorption has been used to concentrate toxic compounds in chlorine-treated water prior to mutagenicity testing (Ringhand et al, 1987). Horth et al (1987) used only XAD-2 resin, whereas Ringhand et al (1987) used both XAD-8 and XAD-2 resins. In the present study, the use of two resins was found to provide better recovery of the model tryptophan-HOC1 reaction mixture than the use of either XAD-2 or XAD-8 resin alone.…”

“…However, these chlorine doses were rather high compared to that used in the flour industry. Sussmuth (1982) and Horth et al (1987) reported that the reaction products of chlorine with certain amino acids were mutagenic in the Ames Salmonellulmicrosome assay.…”

Mutagenic Activity of Concentrated Drinking Water Samples

“…The precursor compounds that are transformed to mutagens during chlorination are probably naturally occurring organics in surface waters, such as humic acids and amino acids (9)(10)(11). The precursor compounds that are transformed to mutagens during chlorination are probably naturally occurring organics in surface waters, such as humic acids and amino acids (9)(10)(11).…”