Occurrence of Disinfection By products (DBPs) in drinking water in different Italian northern regions

Background/Aims: Drinking water chlorination treatments produce different Disinfection By Products (DBPs) as a consequence of the reaction between chlorine in water and natural organic matter. This study is part of the international project HiWATE (Health Impacts of Long-Term Exposure to Disinfection By-Products in Drinking Water) funded by the EU Sixth Framework Programme (FP6). The aim was to investigate the presence of DBPs in drinking water in different northern regions in Italy, where groundwater with low organic matter is generally supplied and where the use of chlorine dioxide as chlorination treatment is widespread.Methods: Bromate, chlorite, chlorate, haloacetic acids (HAAs) and 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and trihalomethanes (THMs) levels were investigated in drinking water samples collected form 12 waterworks located in Emilia Romagna, Friuli Venezia Giulia and Lombardia Regions. To investigate seasonal variability, water samples were collected over four seasons from 2007 to 2008.Results: MX and HAAs were never detected (detection limit: 0.5ng/l and 1μg/l, respectively). THMs were always found at very low concentrations regardless of the disinfection treatment (mean: 2.04μg/l, maximum value: 26.9μg/l). Bromate was detected only in 1 waterworks in which disinfection was performed by ozone and chloride dioxide (range 2-14μg/l). Chlorite was found only in chlorine dioxide disinfected drinking water (4 waterworks; mean value: 136μg/l; range:28-523μg/l), while chlorate resulted the most widespread DBP (>85% of the samples), with concentrations ranging from 1μg/l to 399μg/l. No consistent general trends were observed, in terms of DBPs seasonal variations, in the investigated Italian drinking waters.Conclusion: DBPs levels in Italian drinking water appear generally low, however individual DBPs and levels vary according to the different disinfection treatments: when chlorine dioxide is applied as disinfection method high values of chlorite and chlorate could have been detected. Due to their potential health effects, the presence of chlorite and chlorate in drinking water deserve further investigation.