Dissolved Organic Matter Modulates Concentrations and Bacterial Preferences of Organophosphate Esters and Phthalates

Organophosphate esters (OPEs) and phthalates (PAEs) are pervasive emerging pollutants in water environments. In natural circumstances, the concentrations and behaviors of the OPEs and PAEs are inevitably influenced by various environmental factors, but the driving mechanisms behind these are still unclear. This study focused on the main tributary of the Yangtze River basin: Chishui River. It quantified the contents and sources of OPEs and PAEs and integrated DOM and microbial characteristics to specifically analyze the key driving factors influencing pollutant levels. The results showed that the concentration ranges of OPEs and PAEs from Chishui River were 8.92 × 10²-1.37 × 10³ and 39.6-1.04 × 10³ ng/L in water and 1.85 × 10³-3.63 × 10³ and 1.10 × 10²-1.43 × 10⁴ ng/g dry weight in sediment. TEP, DBEP, and DMEP were the main components requiring prioritized attention. These pollutants mainly originate from domestic waste and industrial plastics. The levels of the OPEs and PAEs were regulated by DOM adsorption and microbial degradation, respectively. Protein-like fluorophore at E_x/E_m: 275/342 nm and FI jointly verified the wastewater source of TBEP. a253/a203 demonstrated potential for monitoring the concentration of TCrP. Tolerant Exiguobacterium exhibited potential for degrading PAEs. Optical signatures of the DOM served as potential tracers for monitoring the OPEs in environmental matrices. These provide new insights into the risk assessment and fate of emerging pollutants in the natural environment.