DGT induced fluxes in sediments model for the simulation of phosphorus process and the assessment of phosphorus release risk

Wu, Zhihao; Wang, Shengrui; Zhang, Li; Jiao, Lixin

DGT induced fluxes in sediments model for the simulation of phosphorus process and the assessment of phosphorus release risk

2016

Wu, Zhihao | Wang, Shengrui | Zhang, Li | Jiao, Lixin

Diffusive gradients in thin films (DGT)-induced flux in sediments (DIFS) (DGT-DIFS) model for phosphorus (P) has been investigated to provide a numerical simulation of a dynamic system of the DGT–pore water–sediment in Dianchi Lake (China). Kinetic parameter—T C (33–56,060 s), distribution coefficient—K d (134.7–1536 cm³g⁻¹), and resupply parameter—R (0.189–0.743) are derived by DGT measurement, the sediment/pore water test, and the DIFS model. The changes of dissolved concentration in DGT diffusive layer and pore water and sorbed concentration in sediment, as well as the ratio of C DGT and the initial concentration in pore water (R) and mass accumulated by DGT resin (M) at the DGT–pore water–sediment interface (distance) of nine sampling sites during DGT deployment time (t) are derived through the DIFS simulation. Based on parameter and curves derived by the DIFS model, the P release-transfer character and mechanism in sediment microzone were revealed. Moreover, the DGT-DIFS parameters (R, T C , K ₋₁ , C DGT), sediment P pool, sediment properties (Al and Ca), and soluble reactive P (SRP) in overlying water can be used to assess “P eutrophication level” at different sampling sites with different types of “external P loading.” The DGT-DIFS model is a reliable tool to reveal the dynamic P release in sediment microzone and assess “internal P loading” in the plateau lake Dianchi.

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