title: Occurrence of carboxylic acids in different steps of two drinking-water treatment plants using different disinfectants.
abstract: The occurrence of 35 aliphatic and aromatic carboxylic acids within two full scale drinking-water treatment plants was evaluated for the first time in this research. At the intake of each plant (raw water), the occurrence of carboxylic acids varied according to the quality of the water source although in both cases 13 acids were detected at average concentrations of 6.9 and 4.7 μg/L (in winter). In the following steps in each treatment plant, the concentration patterns of these compounds differed depending on the type of disinfectant applied. Thus, after disinfection by chloramination, the levels of the acids remained almost constant (average concentration, 6.3 μg/L) and four new acids were formed (butyric, 2-methylbutyric, 3-hydroxybenzoic and 2-nitrobenzoic) at low levels (1.1-5 μg/L). When ozonation/chlorination was used, the total concentration of the carboxylic acids in the raw water sample (4.7 μg/L) increased up to 6 times (average concentration, 26.3 μg/L) after disinfection and 6 new acids (mainly aromatic) were produced at high levels (3.5-100 μg/L). Seasonal variations of the carboxylic acids under study showed that in both plants, maximum levels of all the analytes were reached in the coldest months (autumn and winter), aromatic acids only being found in those seasons.
authors.affiliation: Department of Analytical Chemistry, Campus of Rabanales, University of Córdoba, E-14071 Córdoba, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Jurado-Sánchez
authors.affiliation: Department of Physical and Analytical Chemistry, E.P.S. of Linares, University of Jaén, E-23700 Linares, Jaén, Spain. Electronic address: eballes@ujaen.es.
authors.forename: Evaristo
authors.initials: E
authors.lastname: Ballesteros
authors.affiliation: Department of Analytical Chemistry, Campus of Rabanales, University of Córdoba, E-14071 Córdoba, Spain. Electronic address: mercedes.gallego@uco.es.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Gallego
mesh_terms: D002264:Carboxylic Acids / Q000032:analysis*; D004202:Disinfectants / Q000032:analysis; D060766:Drinking Water / Q000737:chemistry*; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D054879:Halogenation; D012621:Seasons; D013030:Spain; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: D002264:Carboxylic Acids; D004202:Disinfectants; D060766:Drinking Water; D014874:Water Pollutants, Chemical
keywords: Carboxylic acids; Chloramination; Drinking-water treatment plant; Ozonation/chlorination