DOI: 10.5194/hess-18-4687-2014
Scopus记录号: 2-s2.0-84913573323
论文题名: Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water
作者: Van Der Grift B ; , Rozemeijer J ; C ; , Griffioen J ; , Van Der Velde Y
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2014
卷: 18, 期: 11 起始页码: 4687
结束页码: 4702
语种: 英语
Scopus关键词: Agriculture
; Aquifers
; Catchments
; Dissolution
; Effluents
; Groundwater resources
; Hydrogeology
; Iron compounds
; Oxidation
; Oxidation resistance
; Tubes (components)
; Water quality
; Climatic conditions
; Discharge measurements
; Dissolved phosphates
; Experimental catchments
; Ground water discharge
; Immobilization process
; Surface complexation
; Water quality sampling
; Surface waters
; catchment
; concentration (composition)
; flow pattern
; groundwater-surface water interaction
; hydrogeochemistry
; immobilization
; iron
; oxidation
; phosphate
; reaction kinetics
英文摘要: The retention of phosphorus in surface waters through co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and P immobilization along the flow-path from groundwater into surface water in an agricultural experimental catchment of a small lowland river. We physically separated tube drain effluent from groundwater discharge before it entered a ditch in an agricultural field. Through continuous discharge measurements and weekly water quality sampling of groundwater, tube drain water, exfiltrated groundwater, and surface water, we investigated Fe(II) oxidation kinetics and P immobilization processes. The oxidation rate inferred from our field measurements closely agreed with the general rate law for abiotic oxidation of Fe(II) by O2. Seasonal changes in climatic conditions affected the Fe(II) oxidation process. Lower pH and lower temperatures in winter (compared to summer) resulted in low Fe oxidation rates. After exfiltration to the surface water, it took a couple of days to more than a week before complete oxidation of Fe(II) is reached. In summer time, Fe oxidation rates were much higher. The Fe concentrations in the exfiltrated groundwater were low, indicating that dissolved Fe(II) is completely oxidized prior to inflow into a ditch. While the Fe oxidation rates reduce drastically from summer to winter, P concentrations remained high in the groundwater and an order of magnitude lower in the surface water throughout the year. This study shows very fast immobilization of dissolved P during the initial stage of the Fe(II) oxidation process which results in P-depleted water before Fe(II) is completely depleted. This cannot be explained by surface complexation of phosphate to freshly formed Fe-oxyhydroxides but indicates the formation of Fe(III)-phosphate precipitates. The formation of Fe(III)-phosphates at redox gradients seems an important geochemical mechanism in the transformation of dissolved phosphate to structural phosphate and, therefore, a major control on the P retention in natural waters that drain anaerobic aquifers. © Author(s) 2014. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78068
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Innovation, Environmental and Energy Sciences, Faculty of Geosciences, Utrecht University, P.O. Box 80115, TA Utrecht, Netherlands; Deltares, P.O. Box 85467, AL Utrecht, Netherlands; Soil Geography and Landscape, Wageningen University and Research Centre, Droevendaalsesteeg 4, PB Wageningen, Netherlands
Recommended Citation:
Van Der Grift B,, Rozemeijer J,C,et al. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water[J]. Hydrology and Earth System Sciences,2014-01-01,18(11)