Chemical trace analysis and understanding of odor deviations in drinking water in Ghent

During storage and distribution of drinking water, the quality is influenced by both microbiological and physical-chemical processes, which can lead, amongst others, to taste and odor (T&O) deviations. As these deviations give the consumer a negative quality and safety perception, it is important to measure these T&O compounds and get insights into their formation pathways to ensure tasteful tap water. The major challenge here is that these T&O compounds are numerous and at least partially unknown, and can be perceived already at very low concentrations, which makes their identification and quantification difficult. In this respect, a new analytical method was developed based on thermal desorption gas chromatography-mass spectrometry, proceeded by a concentration step using stir bar sorptive extraction. Different parameters such as extraction time, phase ratio, and desorption conditions were experimentally optimized. The final method was used to investigate odor deviations in drinking water collected in multiple student rooms in Ghent. Nineteen (19) locations with reported bad smelling/tasting tap water were sampled and analyzed. Chromatograms were screened for thirty-two (32) possible T&O compounds, and 9 (13) of them were quantified (identified). In addition, a link was found between the described odor character (musty) of some samples and the presence of 2,4,6-tribromoanisole (0.72 - 1.9 ng.L-1) at concentrations well above the odor threshold concentration (8 pg.L-1). This research contributes to the understanding of odor deviations in drinking water in Ghent