Effects of suspended particular matters, excess PO43-, and salinity on phosphorus speciation in coastal river sediments

Zhao, Guoqiang; Sheng, Yanqing; Wang, Wenjing; Liu, Qunqun; Jiang, Ming; Yi, So-yŏn

Effects of suspended particular matters, excess PO43-, and salinity on phosphorus speciation in coastal river sediments

2020

Phosphorus (P) is an essential biogenic element in aquatic ecosystem, and its speciation in sediment may influence the water quality. The composition of P in suspended particular matters (SPM) and sediments were analyzed. Metal ions bonding PO₄³⁻ and chelating organic P (OP) were explored by Visual MINTEQ simulation and infrared spectroscopy. Inorganic P (IP) mainly comprises orthophosphate and pyrophosphate in SPM. OP mainly includes α-glycerol phosphate, β-Gly, monophosphate, and mononucleotides from aquatic plants in SPM. Cyclotella, Nitzschia, Amphiprore, and terrestrial C₃ plants are the main source of aquatic plants in JH, while they are from Oscillatoria and Merismopedia in JL. These aquatic plants directly determine whether OP or IP is taken to surface sediments during the setting of SPM. The bonding between PO₄³⁻ and Ca is more preferential than Al and Fe, so the excess PO₄³⁻ makes Ca compounds bonding IP (Ca-IP) and Al/Fe/Mn (hydr) oxides associated IP (Al/Fe/Mn-IP) dominant, but limited PO₄³⁻ preferentially contributes more Ca-IP. Metal ions in saline water can firmly cheat with OP via P-OH and/or P=O groups to promote the burial of OP.

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