Hidrológiai Közlöny 1992 (72. évfolyam)

1. szám - Varga Csaba: A testvérkromatid-csere (SCE) analízis alkalmazása a vízminőség vizsgálatban. II. rész: Ózonozott-klórozott ivóvíz XAD frakcióinak genotoxicitás vizsgálata humán perifériás limfocita-rendszerben

8 HIDROLÖGIAI KÖZLÖNY 1992. 72. 35VF., 1. SZÁM Zoeteman, B. G. J., Hrubec, J., de Greef, E., Kool, H. J., 1982. Mutagenic activity associated with by-products of drinking water disinfection by chlorine, chlorine A kézirat beérkezett: 1990. október 20. dioxidé, ozone and UV-irradiation. Environ. Health Az átdolgozás beérkezett: 1991. július 30. Perspect. 46: 197—205. Közlésre elfogadva: 1991. július 31. Application of tlie sister cbroinatid excliange (SCE) analysis to water hygiene. Part 2. Studies on XAD isolates of ozonated/chlorinated drinking water in humán pripheral lymphocyte system "Varga, Cs. Abstract: Ozonated/chlorinated drinking water produced by a surface water treatment plánt was examined as to whether genotoxins were förmed by the treatment process. Technology examined includes ozonation (oxidation) and chlorination (disinfection), but excludes GAC or slow sand filtration following the ozonation step (Table. 1. and 2.). Investigations involved cytogenetic assays (chromosomal aberration and SCE analyses) of 70 h humán peripheral lymphocyte cultures after treatment with water isolates obtained on XAD resins (Table 3.). Neutral XAD—2/4, XAD—8 and acidic (pH 2) XAD—2/4—8 fractions were tested separately in 1—10—20 fú/ml concentrations without metabolic activation. A weak, but dose-dependent SCE-inducing activity could be detected only upon treatment with the neutral XAD—2/4 fraction (Fig. 1. and 2.J. Clastogenicity was not observed in the concentration rangé given (Table 4). Correlation could not be found between trihalomethane levels and genotoxicity (Fig. 3.). Based on the literature results on the ozone/chlorine combined treatment one can conclude as a generál rule, that the greater the extent of oxidative degradation of precursors (e. g. humic substances) by ozone, the less proficient the substrate will be for reactions with chlorine leading to mutagenic products. Results presented here show an excellent coincidence with these data. This can be explained by the fact that (a) 12—15% of the suspended material are humic substances (fulvic acid) in the raw water, (b) ozone dosages applied during the treatment are very low, and (c) there is a subsequent long-term exposure of the water to could produce genohigh chlorine dosages. The fact that subsequent chlorination of the preozonated water toxins suggests the necessity of technologic clianges in waterworks applying similar scheme. GAC filtration (before chlorination), increased ozone level applied or subsequent chloramination (instead of chlorination) may be good means of eliminating the genotoxic compounds or their precursors. Thus the exposure of humans to byproducts in drinking water may be minimized. Keywords: drinking water; XAD isolates; ozone/chlorine treatment; genotoxicity; chromosomal aberrations; sister chromatid exchanges; VARGA CSABA Szakmai működésének összefoglalóját a Hidrológiai Közlöny 1988. évi 4. számának 236. oldalán, illetőleg az 1991. évi 5. számának oldalán közöltük.