Assessment of Haloacetic Acids in Drinking Water in Bizerte, Tunisia

摘要

An investigation into the occurrence of haloacetic acids (HAAs) was conducted during a period of winter and summer seasons of the years 2008–2009 on the drinking water of Bizerte with variable conditions of water quality, pH, water temperature, total organic carbon, and bromide concentrations. The concentrations of HAAs were determined by a fast headspace solid-phase microextraction GC method, which consists of liquid–liquid extraction, evaporation to dryness of extraction solvent then derivatization of the HAAs to their methyl haloacetates with sulfuric acid and methanol, followed by headspace solid-phase microextraction with GC and electron capture detection. The results of the analyses show the presence of HAAs in all chlorinated water samples. The most prevalent HAAs were trichloroacetic acid (TCAA), dichloroacetic acid (DCAA), and monochloroacetic acid (MCAA) due to the low concentrations of bromide in the water treatment plant, while other HAAs were detected at low concentrations. The annual means concentrations of TCAA, DCAA and, MCAA varied from 3.9 to 26.25 µg L−1, from 2.76 to 23.19 µg L−1, and from 6.65 to 34.07 µg L−1, respectively. Seasonal variations in HAAs were mainly linked with changes in water temperature and variations of organic precursors, with HAA occurrence at its highest in summer. In all samples the concentrations of HAAs were lower than the maximum level set by the World Health Organization except for MCAA at the network extremity. Finally, a statistically significant (p < 0.05) regression analysis was used to examine the correlation of HAA5 with respect to some water quality parameters. Strong correlations between (total organic carbon, water temperature and chlorine dose) with HAA5 were observed.