Bacterial diversity across four drinking water distribution systems in Croatia: impacts of water management practices and disinfection by-products

• Published in: FEMS microbiology ecology Vol. 99; no. 1
• Main Authors: Štiglić, Jurica, Ujević Bošnjak, Magdalena, Héry, Marina, Kurajica, Livia, Kinsela, Andrew S, Casiot, Corinne, Capak, Krunoslav
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.01.2023; Wiley-Blackwell
• Subjects: Bacteria; By products; Byproducts; Correlation; Dichloroacetic acid; Disinfectants; Disinfection; Disinfection & disinfectants; Drinking water; Ecology; Environmental Sciences; Haloacetic acids; Lactobacillus; Microbiology; Mycobacterium; Ralstonia; Raw water; rRNA 16S; Species diversity; Species richness; Sphingomonas; Water distribution; Water distribution systems; Water engineering; Water management; Water treatment; bacterial diversity; source water; tap water; disinfection by-products
• ISSN: 1574-6941; 0168-6496; 1574-6941
• DOI: 10.1093/femsec/fiac146

Abstract Several factors may impact bacterial diversity in drinking water distribution systems (DWDSs) including the origin of the raw water, the water treatment technologies, and the disinfection practices applied. 16S rRNA metabarcoding was used for the in-depth characterization of bacterial communities in the four studied Croatian DWDSs (A, B, C, D) two of which had residual disinfectant (A, B) and two were without (C, D), while only B utilized the conventional water treatment technology. Significantly higher diversity and species richness were evidenced in non-disinfected DWDSs (P<0.05) compared to disinfected DWDSs. The phylum Proteobacteria was the most abundant in all the DWDSs, being proportionately higher in non-disinfected systems (P<0.05). The most abundant genera in DWDS-A Mycobacterium and Sphingomonas both positively correlated, whereas Lactobacillus negatively correlated with the concentration of disinfection by-products (DBPs) as a sum of haloacetic acids (HAAs). Conversely, the genus Ralstonia positively correlated with the individual DBP dichloroacetic acid. These results indicate that genera Sphingomonas, Mycobacterium, Lactobacillus, and Ralstonia could have an effect on promoting the formation of DBPs, in a similar manner to how negatively correlated taxa may influence their degradation. Bacterial diversity assessed across four DWDSs: Proportion of Proteobacteria higher in non-disinfected than in disinfected systems; Sphingomonas, Mycobacterium, Lactobacillus, and Ralstonia could have an effect on promoting the formation of DBPs; Bacterial diversity in a post-treated and disinfected DWDS higher than in raw water.