title: Characterization of colloidal phosphorus species in drainage waters from a clay soil using asymmetric flow field-flow fractionation.
abstract: Phosphorus transport from agricultural land contributes to eutrophication of surface waters. Pipe drain and trench waters from a grassland field on a heavy clay soil in the Netherlands were sampled before and after manure application. Phosphorus speciation was analyzed by physicochemical P fractionation, and the colloidal P fraction in the dissolved fraction (<0.45 μm) was analyzed by asymmetric flow field-flow fractionation (AF4) coupled to high-resolution inductively coupled plasma-mass spectrometry and ultraviolet diode array detector. When no manure was applied for almost 7 mo, total P (TP) concentrations were low (<21 μmol L), and TP was almost evenly distributed among dissolved reactive P (DRP), dissolved unreactive P (DUP), and particulate P (PP). Total P concentrations increased by a factor of 60 and 4 when rainfall followed shortly after application of cattle slurry or its solid fraction, respectively. Under these conditions, DRP contributed 50% or more to TP. The P speciation within the DUP and PP fractions varied among the different sampling times. Phosphorus associated with dissolved organic matter, probably via cation bridging, comprised a small fraction of DUP at all sampling times. Colloidal P coeluted with clay particles when P application was withheld for almost 7 mo and after application of the solid cattle slurry fraction. At these sampling times, PP correlated well with particulate Fe, Al, and Si, indicating that P is associated with colloidal clay particles. After cattle slurry application, part of DUP was probably present as phospholipids. Physicochemical fractionation combined with AF4 analysis is a promising tool to unravel the speciation of colloidal P in environmental water samples.
authors.forename: Inge C
authors.initials: IC
authors.lastname: Regelink
authors.forename: Gerwin F
authors.initials: GF
authors.lastname: Koopmans
authors.forename: Caroline
authors.initials: C
authors.lastname: van der Salm
authors.forename: Liping
authors.initials: L
authors.lastname: Weng
authors.forename: Willem H
authors.initials: WH
authors.lastname: van Riemsdijk
mesh_terms: D000818:Animals; D004322:Drainage; D008372:Manure; D010758:Phosphorus / Q000737:chemistry; D012987:Soil; D012989:Soil Pollutants; D014867:Water; D014872:Water Movements
chemical_list: D008372:Manure; D012987:Soil; D012989:Soil Pollutants; D014867:Water; D010758:Phosphorus