Understanding the controls on sediment-P interactions and dynamics along a non-tidal river system in a rural–urban catchment: The River Nene

摘要: The release of Phosphorus (P) from river sediments has been identified as a contributing factor to waters failing the criteria for ‘Good Ecological Status’ under EU Water Framework Directive (WFD). To identify contribution sediment-P systems, an understanding factors that influence its distribution within entire non-tidal system is required. Thus aims this work were examine (i) total (PTotal) and labile (PLabile) concentrations in sediment, (ii) sequestration processes (iii) interactions between sediment P water six bodies River Nene, U.K. Collection followed long period flooding high stream flow. In each body, five cores extracted homogenised analysis with additional core being taken sampled by depth increments. Comparing particle size PTotal data soil catchment geochemical survey data, large increases body 4–6, where median (3603 mg kg−1) up double those soils. A proportion increase may be related in-stream sorption P, particularly sewage treatment facilities becomes more urbanised after 3. linear correlation (r = 0.8) soluble reactive phosphate (SRP) Boron was found suggesting increased STW input 4–6. PLabile 100 kg−1 PO4–P (generally < 2% PTotal) showed general distance headwaters. Equilibrium Phosphate Concentrations (EPC0) average 0.9–∼1.7 μm L−1 1–3 4–6. Fixation oxalate extractable phases (Al, Fe Mn) accounted ∼90% binding but only 31 74% 1–3. Statistical models predicting (R2 0.78), 0.78) Olsen 0.73) Mn oxy-hydroxides (MnOx) strong predictive variable along location system. It suggested MnOx model predictions identifying pool mixed Fe–Mn (MnOx–FeOOH) or oxy-hydroxide (FeOOH) wider FeOxalate are effective at sorbing fixing P. findings demonstrate how accumulate km system, extent which range can fix mineral natural flush channel. study likely applicable similar systems over their eastern England.