Fig. 5: Van Krevelen diagrams of unique compounds in water SPE-DOM of pre-WSRS, water release phase (WRP), and sediment flushing phase (SFP).

a Unique CHO compounds, b unique CHON compounds, c unique CHOS compounds, and d unique CHONS compounds in pre-WSRS, respectively; e unique CHO compounds, f unique CHON compounds, g unique CHOS compounds, and h unique CHONS compounds in WRP, respectively; i unique CHO compounds, j unique CHON compounds, k unique CHOS compounds, and l unique CHONS compounds in SFP, respectively.