REACTIONS OF POLYNUCLEAR AROMATIC-HYDROCARBONS WITH CHLORINE AND CHLORINE DIOXIDE IN COAL-TAR LINED PIPES

In the presence of disinfectants, PAH are remobilised from the coal ta r lining of water distribution mains. Reactions of the PAH with chlori ne and chlorine dioxide can lead to chlorinated PAH that might show hi gher mutagenic effects than the parent PAH. Detection limits in the lo wer nanogram-per-litre level for the determination of PAH and chlorina ted PAH were achieved by using solid phase micro extraction and a gas chromatographic mass spectrometric device. Thus, the reactions of four PAH (anthracene, fluoranthene, fluorene and phenanthrene) with chlori ne and chlorine dioxide under conditions and at concentrations of comm on practice in the drinking water distribution system could be investi gated. In batch experiments with demineralised and drinking water at p H 7, the concentrations of fluoranthene, fluorene and phenanthrene rem ained constant, whereas anthracene reacted quantitatively with both di sinfectants. The reaction of anthracene followed a pseudo-first order kinetic. In these reactions no chlorinated products could be detected, only monohydroxyanthracene and anthraquinone were identified. A react ion mechanism for both reaction products is suggested. Additionally th e toxic effect of a set of chlorinated and oxidised PAH was examined: at 0.5 mg/L only hydroxyphenanthrene and phenanthrene-quinone reduced the activity of luminescent bacteria whereas no compound affected the microcrustacean Daphnia magna. The fluorescence emission spectra of ox idised and chlorinated PAH show significant alterations when compared to the spectra of the parent compounds.