Monodisperse ferrous phosphate colloids in an anoxic groundwater plume

Philip M. Gschwend; Matthew D. Reynolds

doi:10.1016/0169-7722(87)90011-8

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Monodisperse ferrous phosphate colloids in an anoxic groundwater plume

Philip M. Gschwend·Matthew D. Reynolds

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Abstract

Groundwater samples collected near a secondary-sewage infiltration site on Cape Cod, Massachusetts were examined for colloidal materials (10–1000 nm). In two wells the water contained a population of monodisperse 100-nm particles, detected using laser-light scattering and autocorrelation data processing. SEM and SEM-EDAX analysis of these colloidal materials collected on ultrafilters confirmed the laser light scattering result and revealed that these microparticles consisyed of primarily iron and phosphorus in a 1.86 Fe to 1.0 P stoichiometric ratio. Chemical analyses of the water samples, together with equilibrium solubility calculations, strongly suggest that the ion-activity product should exceed the solubility product of a 100-nm diameter predominantly vivianite-type (Fe 3 (PO 4 ) 2 · 8H 2 O) colloidal phase. In light of our results, we conclude that these microparticles were formed by sewage-derived phosphate combining with ferrous iron released from the aquifer solids, and that these colloids may be moving in the groundwater flow. Such a subsurface transport process could have major implications regarding the movement of particle-reactive pollutants traditionally viewed as non-mobile in groundwater.

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Journal of Contaminant Hydrology Article

Source-reported bounding extent: 41.36031866306708° to 42.13082130188811° latitude; -70.850830078125° to -69.8291015625° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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BibTeX RIS

Philip M. Gschwend, Matthew D. Reynolds. 1987. Monodisperse ferrous phosphate colloids in an anoxic groundwater plume. https://doi.org/10.1016/0169-7722(87)90011-8

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