| Abstrakt: |
Abstract This study examined the interplay between bromide and DOM characteristics, described with SUVA 254 , in terms of formation and speciation of selected DBPs [trihalomethanes (THMs), haloacetic acids (HAAs), and haloacetonitriles (HANs)] during chlorination under various water treatment conditions. Cytotoxicity evaluations were also conducted based on the types and amounts of DBPs formed and their corresponding cytotoxicity index values. The results showed that the formation of THMs and HAAs increased as the specific UV absorbance at 254 nm (SUVA 254) of the waters increased; however, there was no clear trend for HANs. THM and HAN formation increased with increasing bromide levels, while there was no bromide effect on the HAA formation. Lower HAA5 (monochloroaceticacid, monobromoaceticacid, dichloroaceticacid, trichloroaceticacid, dibromoaceticacid) to HAA9 (monochloroaceticacid, monobromoaceticacid, dichloroaceticacid, trichloroaceticacid, dibromoaceticacid, bromochloroaceticacid, bromodichloroaceticacid, dibromochloroaceticacid, tribromoaceticacid) ratios, independent of SUVA 254 , were observed with increasing bromide levels. Bromine substitution factor (BSF) values were in the order of BSF DHAN > BSF THAA > BSF THM ≈ BSF DHAA. BSF values for all class of DBPs decreased with increasing SUVA 254. TOX formation increased with increasing SUVA 254 without an impact of bromide concentration. UTOX/TOX ratios were higher in treated low SUVA 254 waters than raw waters having higher SUVA 254 values, and they decreased with increasing initial bromide concentration in all sources. Increasing bromide concentration from 0.5 μM to 10 μM elevated the calculated cytotoxicity index values of waters. Despite their much lower (approximately ~10 times) formation as compared to THMs and HAAs, HANs controlled the calculated cytotoxicity of studied waters. Graphical abstract Unlabelled Image Highlights • High SUVA waters had low BSF, while low SUVA waters had high BSF. • Increasing pH, increased the BSF in THM, THAA, and DHAN. • Increasing Cl 2 , decreased the BSF for HAAs and HANs, and THMs. • In high SUVA waters, UTOX/TOX ratio was lower than low SUVA waters. [ABSTRACT FROM AUTHOR] |
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