Soil-borne mobile colloids as influenced by water flow and organic carbon
- Univ. of Georgia, Aiken, SC (United States)
Paucity of understanding mechanisms relevant to the generation of subsurface mobile colloids is a major limitation to our current knowledge of colloid-facilitated contaminant transport. To evaluate the roles of natural organic materials and pore water velocity on mobile colloid generation, colloids generated from 14-m{sup 3} lysimeters containing reconstructed soil profiles were collected and characterized. Colloids generated during low flow rates were 1030% less abundant, contained at least 65% more iron oxides and gibbsite, were 80% smaller, and had 40% greater electrophoretic mobility than colloids generated during higher flow rates. Quartz, kaolinite, and hydroxy-interlayered vermiculite were enriched by at least 32% in colloids generated during faster flow rates. Mobile colloid surface charge was greatly enhanced by organic carbon (OC) coatings. Concentrations of OC associated with mobile colloids were higher than or equal to the OC concentrations existing in the bulk soils from which the mobile colloids were derived. The profound effects of pore water flow rate and OC on mobile colloid generation introduces complexity to this potentially critical, yet poorly understood, component of subsurface contaminant transport. 41 refs., 8 figs., 1 tab.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 42542
- Journal Information:
- Environmental Science and Technology, Vol. 27, Issue 6; Other Information: PBD: Jun 1993
- Country of Publication:
- United States
- Language:
- English
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