Reactions of PAH with Chlorine and Chlorine Dioxide in Coal Tar Lined Pipes

Abstract

In presence of disinfectants, PAH are remobilized from the coal tar lining of water distribution mains. Reactions of the PAH with chlorine and chlorine dioxide can lead to chlorinated PAH that might show higher mutagenic effects than the parent PAH. The application of the solid‐phase microextraction as a sampling preparation method in combination with a gas chromatographic mass spectrometric device is a reliable and useful method to achieve detection limits in the lower nanogramme‐per‐liter level for PAH and chlorinated PAH. Thus, the reactions of four PAH (anthracene, fluoranthene, fluorene, and phenanthrene) with chlorine and chlorine dioxide under conditions prevalent in drinking water distribution systems could be investigated. In batch experiments with demineralized and drinking water at pH 7, the concentrations of fluoranthene, fluorene, and phenanthrene remained constant, whereas anthracene reacted quantitatively with both disinfectants. In these reactions, no chlorinated products could be detected, only mono‐hydroxyanthracene and anthraquinone were formed. A reaction mechanism for both reaction products is proposed. The results suggest that oxidation is the major pathway of the reaction of PAH with disinfectants in the systems under investigation.

Reactions of Chlorine Dioxide with Organic Compounds

“…In reactions with polycyclic aromatic hydrocarbons, the reaction kinetics obeys the first-order kinetic law for both reagents [4,73]; the rate constants correlate with the half-wave oxidation potentials of PAHs and with the energies of their highest occupied molecular orbitals [4].…”

“…Oxidation of polycyclic aromatic hydrocarbons mainly forms quinoid products, but scarcely any chloro derivatives. Thus anthraquinone [4,73,74], as well as monohydroxyanthracene [73], were found among the products of anthracene oxidation: Phenanthrene was reported to react with chlorine dioxide at reasonably high concentrations in carbon tetrachloride, forming diphenic acid and 10,10-dichloro-9-phenanthrone [75].…”

Mass Spectrometry in Environmental Sciences

“…Detection limits for the SPME method were reported to be 10−200 ng/L . Merkel et al also recently reported an SPME-GC/MS method for determining drinking water DBPs, and Prakash et al reported the performance of a purge-and-trap-GC/ion-trap-MS method for the routine analysis of cyanogen chloride in several hundred drinking water samples . The latter method was used to analyze drinking water samples collected as part of an 18-month national survey associated with the Information Collection Rule and produced detection limits of 0.02 μg/L with a linear dynamic range of 0.1−20 μg/L…”