[Distribution, Migration, and Transformation Mechanism of Labile Phosphorus in Sediments of Xixi River Estuary, Xiamen].

To explore the effect of manganese, iron, and sulfur geochemistry on the distribution of labile phosphorus in different estuarine areas, the diffusion gradient in thin-film (DGT) sampling technique was used for in-situ high-resolution monitoring of available phosphorus (DGT-P), manganese, iron, and sulfur in sediments from Xixi River estuary in Xiamen. The results showed that the distribution of DGT-P in the vertical profile was closely related to the redox transformation of iron and sulfur and the background value of active phosphorus in sediments. The passivation/activation of phosphorus was mainly controlled by the oxidative adsorption/reductive dissolution of phosphorus by iron oxides and the activation of phosphorus induced by sulfate reduction and sulfide accumulation.

Characterization of dissolved organic matter in groundwater from the Coastal Dagu River watershed, China using fluorescence excitation-emission matrix spectroscopy.

The fluorescent properties of dissolved organic matter (DOM) from groundwater in the coastal Dagu River watershed, North China were determined using excitation-emission matrix spectroscopy (EEMs) analysis. Surface water DOM samples were also investigated for comparison. Two humic-like components (C1: 250, 355/472 nm; C2: < 240, 325/400 nm) and one protein-like component (C3: <240, 280/340 nm) were identified using parallel factor analysis.