Investigating Taste and Odour Characteristics in a Drinking Water Source: A Comprehensive 3-Year Monitoring Study

The monitoring of drinking water quality is a vital public health concern together with taste and odour (T&O) episodes, an emerging global problem causing a loss of public trust to the quality of water. Our objective was to monitor water quality of an important drinking water source and also the production dynamics of geosmin and 2-methylisoborneol (2-MIB) which cause taste and odour problems in the lake. The trophic status of the lake was classified as mesotrophic. 2-MIB was positively correlated temperature while geosmin was positively correlated with depth. Other physicochemical parameters related with water quality did not show significant correlation with geosmin and 2-MIB. The highest 2-MIB and geosmin concentrations were detected during the thermal stratification period in 2016 and 2018 by gas chromatography-mass spectrometry (GC-MS). Cyanobacteria and Actinobacteria were detected in geosmin & 2-MIB detected samples as potential taste and odour producers by PCR. Selected samples were analysed with metabarcoding and Planktothrix, Pseudanabaena, Cyanobium, Streptomyces, and Nocardioides were detected as potential geosmin & 2-MIB producers. Micrococcus, Rhodococcus, Acinetobacter, Comamonas, Novosphingobium, Sphingopyxis, Pseudomonas, Sphingomonas, Stenotrophomonas and Flavobacterium were identified as potential geosmin & 2-MIB degraders. The results highlighted the significant role of the autochthonous bacterial community, temperature and thermal stratification in the taste and odour dynamics of a drinking water source.