Using UV–Vis differential absorbance spectra of tropical peat water DOM fraction to determine trihalomethanes formation potential and its estimated cytotoxicity

Absorbance differential spectra could be utilized to identify dissolved organic matter (DOM) characteristics such as the disinfection by products (DBPs) formation. This research purposed to establish the relationship between absorbance differential spectra and trihalomethanes-4 (THM4) formation potential, as well as the estimated cytotoxicity of tropical peat water DOM percentage. The ion exchange resin was used to separate the DOM components from peat water. In addition, the UV–Vis spectrum was examined between 200 and 700 nm. The hydrophobic-acid (HPOA) fraction contains the highest concentration of dissolved organic carbon (DOC), THM4 production potential, and calculated cytotoxicity. On the other hand, the hydrophilic-neutral (HPIN) fraction has the lowest potential THM4 production. The UV–Vis absorbance spectra of all DOM fractions showed a comparable peak at 277 nm. The differential spectra of 277 nm (ΔA₂₇₇) indicated a significant association with DOC concentration (99.6 %), trichloromethane (TCM) creation (86.6 %), total-THM4 (TTHM4) (81.3 %) formation, THM4 estimated cytotoxicity (89.7 %), and a moderate correlation with bromodichloromethane (BDCM) formation (55.6 %). Meanwhile, ΔA₂₇₇ had a poor correlation with brominated THM4 formation potential (chlorodibromomethane (CDBM): 2.59, tribromomethane (TBM): 2.78 %). The absorbance differential spectra might be employed as a surrogate measure for the peat water DOM fraction and its precursor properties to form THM4 during the chlorination process, as well as its estimated cytotoxicity.