Effects of bisphenols and perfluoroalkylated substances on fluorescence properties of humic and amino acids substances of dissolved organic matter: EEM-PARAFAC and ATR-FTIR analysis

Abiotic, biotic, and sparingly the xenobiotic factors are considered to influence the compositional variation of dissolved organic matter (DOM) in aquatic environments. Increasing discharge of xenobiotics into water bodies necessitates the need to investigate their effects on the key components of DOM. The effects of bisphenols (BP) and perfluoroalkylated substances (PFAS) on the fluorescence characteristics of pure humic substances (HS) and amino acids (AA) of DOM were examined by using excitation-emission matrix-parallel factor analysis (EEM-PARAFAC) and the attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy in this work. The results showed that interactions of fulvic acid (FA), humic acid (HA), and tryptophan (Trp) with the xenobiotic compounds could generate some fluorescence components like both HS and AA components, whereas the interactions with tyrosine (Tyr) could only generate AA fluorescence components. In addition, it was revealed that the fluorescence intensity of HS decreases by 50-70% and 18-25% in the treatments of HA and FA, respectively, at low concentration (2.5 × 10-3 mg/L) of BP, while this increases by 350-425% and 18-25% at the same concentration of PFAS. However, both BP and PFAS increase the fluorescence intensity of AA. The findings suggest that the xenobiotic compounds are important factors affecting the compositional variation of DOM, especially in the anthropogenically-impacted water bodies.