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

Abstract

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 PO 4 3and 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 C 3 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 PO 4 3− and Ca is more preferential than Al and Fe, so the excess PO 4 3− makes Ca compounds bonding IP (Ca-IP) and Al/Fe/Mn (hydr) oxides associated IP (Al/Fe/Mn-IP) dominant, but limited PO 4 3− 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.

Effect of salinity on the determination of dissolved non‐reactive phosphorus and total dissolved phosphorus in coastal waters

“…Therefore, Gly would be complexed with Na + and impurity metal ions (such as Ca 2+ , Mg 2+ , Pb 2+ , Fe 2+ , and Zn 2+ ) in NaCl reagent, resulting in the decrease of determination result (Figure 2a). This result was in agreement with previous study, in which the concentration of Gly measured by fresh water and seawater method would decrease under the interference of salinity (Zhao, Sheng, Wang, et al, 2020). Moreover, the Fourier Transform Infrared Spectrometry results of three treatments of Gly also confirmed above conclusions.…”

“…Therefore, a reasonable inference was that IHP had complexed with metal ions in NaCl and K 2 S 2 O 8 reagent, resulting in the decline of its determination results. Furthermore, this was consistent with the results reported by Zhao, Sheng, Wang, et al (2020) which showed IHP6 was prone to complexation with cations in NaCl solution (Zhao, Sheng, Wang, et al, 2020). At the same time, Fourier transform infrared spectroscopy analysis of ultrapure water, NaCl and NaCl + K 2 S 2 O 8 prepared IHP6 solution also confirmed the above results.…”

Content and Speciation of Phosphorus in Lake Kórnickie

“…The biogeochemical cycle and availability of phosphorus depend largely on its chemical forms in the aquatic ecosystem. Taking into account this fact, knowledge of the speciation forms of phosphorus in the water body provides an opportunity to understand the role of phosphorus in water quality regulation [4,5]. From the point of view of increasing eutrophication processes, it is important to understand the processes taking place in reservoirs, as knowledge in this area helps guide lake management practices.…”