Determination of chlorinated 5-methyl-5-hydroxyfuranones in drinking water, in chlorinated humic water, and in pulp bleaching liquor

Hydroxyfuranones with monochloro-, dichloro-, and trichloromethyl groups at C-5 (5-MHFs) were qualitatively and quantitatively determined in extracts of chlorination stage bleaching liquors (CBL) from a pulp mill, of chlorinated natural humic water (HW), and of three samples of drinking water (DW1-3) treated with various disinfectants. In addition, the mutagenic potency of the compounds in Ames tester strain TA100 was observed, and their stability in water at pH 2 and pH 8 was determined. In CBL, eight of the nine hydroxyfuranones studied were observed, and some of the compounds were found in concentrations higher than 0.5 mg/L. Thus, these compounds must be considered as major chlorinated byproducts of chlorine bleaching. In the drinking water extracts, the 5-dichloromethyl compounds and one 5- monochloromethyl compound were detected. The concentration of the compounds ranged from <1 to 45 ng/L. The compounds were found to be mutagenic in the Ames assay; the most potent mutagen generated about 1.5 revertants/nmol, while the weakest mutagen generated about 0.3 revertants/nmol. The total mutagenicity contribution of these hydroxyfuranones was approximately 2% in the sample of CBL and much less than 1% in the samples of drinking water. The stability of the compounds was higher at pH 2 than at pH 8, and in general, a higher degree of chlorine substitution increased the compound stability.