Temporal and spatial variation of trihalomethanes and haloacetic acids concentration in drinking water: A case study of Queensland, Australia

Abstract

A broad survey of regulated trihalomethanes (THM) and haloacetic acids (HAA) concentrations in Queensland drinking water was undertaken and the data were evaluated to assess the overall compliance of the region to Australian Drinking Water Guidelines (ADWG). The results presented here indicate that drinking water total trihalomethane (tTHM) concentrations were predominantly compliant with ADWG, with regions using chlorination being the only regions that exceeded the ADWG for THM. tTHM levels were highest in chlorinated water, whereas levels in combined chlorinated/chloraminated water were much lower. Chloraminated water produced the lowest tTHM levels in the regions examined. tTHM levels generally increased during summer and decreased in winter regardless of disinfection method. Surface waters formed a higher proportion of more highly chlorinated THM species relative to more highly brominated THM species, whereas bore water had a higher proportion of more highly brominated THM species due to the frequently higher bromide concentration and lower natural organic matter (NOM) concentration of these waters. The majority of regions were continuously compliant with ADWG for HAA concentrations, with primarily the trichloroacetic acid guideline value being exceeded, in chlorinated waters only.