Survey of disinfection by-products in drinking water in Athens, Greece

An investigation into the occurrence of disinfection by-products (DBPs) was conducted for a period of two years (2001–2002) on the drinking water of Athens, Greece. Samples from four water treatment plants (WTPs) and from the distribution system of Athens were collected monthly and analyzed for DBPs. The concentrations of DBPs were determined by the gas chromatography–mass spectrometry (GC–MS) method, which included sample preparation with liquid–liquid extraction (LLE) for volatile DBPs and an acidic method of esterification for haloacetic acids (HAAs). The DBPs studied included trihalomethanes (THMs), haloacetonitriles (HANs), haloketones (HAKs), chloral hydrate (CH), chloropicrin (CP) and nine HAAs. The results of the analyses show the presence of DBPs in all water samples collected after prechlorination. The most commonly encountered DBPs were chloroform (CM), trichloroacetic acid (TCAA), dichloroacetic acid (DCAA) and monochloroacetic acid (MCAA), while other volatile DBPs were detected at low concentrations. The annual mean concentrations of CM in four WTPs ranged from 8.0 to 42.5 µg/l, while the annual mean concentrations of TCA, DCA and, MCA varied from 3.5 to 18.1 µg/l, from 2.3 to 24.5 µg/l, and from 1.1 to 61.8 µg/l, respectively. Higher concentrations of THMs and HAAs were measured in the summer and fall compared to winter. In all cases the concentrations of TTHMs were lower than the maximum level set by the European Community.

1. The concentrations of TTHMs and three volatile DBPs (CH, 1,1-DCP, 1,1,1-TCP) were low in Athens chlorinated drinking water, but the concentrations of HAAs (MCAA, MBAA, DCAA, BCAA, TCAA, DBAA, DCBAA) were high and in some cases exceeded the concentrations of TTHMs and other DBPs. 2. The concentration of TTHMs were similar to those measured in Canada where the majority of 53 drinking waters had THM levels below 50 µg/l, in the US where THMs in chlorinated effluents averaged 31 µg/l, and in Finnish drinking water [23]. In all cases the concentrations of TTHMs were lower than the maximum levels set by the EC.