title: Occurrence of THM and NDMA precursors in a watershed: Effect of seasons and anthropogenic pollution.
abstract: In pristine watersheds, natural organic matter is the main source of disinfection by-product (DBP) precursors. However, the presence of point or non-point pollution sources in watersheds may lead to increased levels of DBP precursors which in turn form DBPs in the drinking water treatment plant upon chlorination or chloramination. In this study, water samples were collected from a lake used to obtain drinking water for Istanbul as well as its tributaries to investigate the presence of the precursors of two disinfection by-products, trihalomethanes (THM) and N-nitrosodimethylamine (NDMA). In addition, the effect of seasons and the possible relationships between these precursors and water quality parameters were evaluated. The concentrations of THM and NDMA precursors measured as total THM formation potential (TTHMFP) and NDMA formation potential (NDMAFP) ranged between 126 and 1523μg/L THM and <2 and 1648ng/L NDMA, respectively. Such wide ranges imply that some of the tributaries are affected by anthropogenic pollution sources, which is also supported by high DOC, Cl(-) and NH(3) concentrations. No significant correlation was found between the water quality parameters and DBP formation potential, except for a weak correlation between NDMAFP and DOC concentrations. The effect of the sampling location was more pronounced than the seasonal variation due to anthropogenic pollution in some tributaries and no significant correlation was obtained between the seasons and water quality parameters.
authors.affiliation: Department of Environmental Engineering, Istanbul Technical University, Maslak, Istanbul, 34469, Turkey. aydine@itu.edu.tr
authors.forename: Egemen
authors.initials: E
authors.lastname: Aydin
authors.forename: Fatma Busra
authors.initials: FB
authors.lastname: Yaman
authors.forename: Esra
authors.initials: E
authors.lastname: Ates Genceli
authors.forename: Emel
authors.initials: E
authors.lastname: Topuz
authors.forename: Esra
authors.initials: E
authors.lastname: Erdim
authors.forename: Melike
authors.initials: M
authors.lastname: Gurel
authors.forename: Murat
authors.initials: M
authors.lastname: Ipek
authors.forename: Elif
authors.initials: E
authors.lastname: Pehlivanoglu-Mantas
mesh_terms: D004128:Dimethylnitrosamine / Q000032:analysis*; D011786:Quality Control; D012621:Seasons; D013056:Spectrophotometry, Ultraviolet; D022882:Trihalomethanes / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D022882:Trihalomethanes; D014874:Water Pollutants, Chemical; D004128:Dimethylnitrosamine