Characterization of Colloidal Phosphorus Species in Drainage Waters from a Clay Soil Using Asymmetric Flow Field‐Flow Fractionation

• Published in: Journal of environmental quality Vol. 42; no. 2; pp. 464 - 473
• Main Authors: Regelink, Inge C., Koopmans, Gerwin F., Salm, Caroline, Weng, Liping, Riemsdijk, Willem H.
• Format: Journal Article
• Language: English
• Published: United States The American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc 01.03.2013; American Society of Agronomy
• Subjects: Animals; Clay (material); Colloids; Dissolution; Drainage; Environmental protection; environmental-samples; Fractionation; Manure; Microbiology; minerals; netherlands; organic phosphorus; phosphate adsorption; Phosphorus; Phosphorus - chemistry; Polypropylenes; Sampling; sandy soils; separation; Slurries; Soil; Soil Pollutants; surface runoff; transport; Water; Water Movements; Netherlands
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2012.0322

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−1), 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.