Utilizing differential absorbance spectra to assess dissolved organic matter released from face masks and cardboards under UVA irradiation in bromide-containing water: Correlation with THM4 formation and its potential cytotoxicity

Face masks and cardboard waste can release organic compounds into the waters. This study was conducted to determine the organic compounds released by face masks and cardboard waste in water during UV light irradiation and its effect on trihalomethanes (THMs) formation. UVA irradiation (340 nm) was carried out on each sample in water for 1, 5, 12, 24, and 48 h. UV absorbance spectra were used to determine the changes in absorbance spectra of organic compounds released by each sample in water. Chlorine disinfection was conducted to determine the THM4 formation. Based on the study results, the face mask samples had a differential absorbance spectra (DAS) peak at 245 nm (ΔA245). On the other hand, plain and inscribed cardboard samples have a DAS peak at 277 nm (ΔA277). THM4 formation increased as the UVA irradiation time increased. The inscribed cardboard sample had the highest THM4 formation and its estimated cytotoxicity. Each UV absorbance peak correlates with THM4 formation and its estimated cytotoxicity (above 76 %). ΔA277 in the plain cardboard sample correlated highest with THM4 formation (95 %). Simple UV absorbance spectra can be used to determine the potential formation of THM4 in water highly polluted by face mask and cardboard waste.