HR: 1330h
AN: H32A-0501    [PDF]
TI: The effect of flow heterogeneity on the mobilization of colloids from metal-contaminated soils
AU: * DeNovio, N M
EM: denovio@colorado.edu
AF: University of Colorado - Boulder Department of Civil, Environmental, and Architectural Engineering, UCB 428, Boulder, CO 80309 United States
AU: Ryan, J N
EM: joseph.ryan@colorado.edu
AF: University of Colorado - Boulder Department of Civil, Environmental, and Architectural Engineering, UCB 428, Boulder, CO 80309 United States
AB: In vadose zone soils, colloid-facilitated transport has been shown to play a significant role in contaminant transport because colloids are abundant and the kinetics of contaminant desorption are likely to be slow relative to the time scale for colloid transport through the unsaturated zone. Understanding the rate of colloid generation and transport with respect to the surface area available for contaminant sorption and chemical composition of these colloids is critical for predicting colloid-facilitated transport. Soil cores (approximately 20 cm$^3$)obtained from the Arkansas River Valley in Leadville, Colorado, where there is significant metal contamination, were leached at three rainfall rates corresponding to 10-, 20-, and 100-year storm events. Effluent water samples were collected with a 2.5 cm spatial resolution at the base of the column. Samples were analyzed for colloid concentration, size and metal elements (Pb, Zn, Cu) in addition to Al, Si, and other metals. Despite significant variability in the spatial distribution of water flow, there was little to no variability in the rate of colloid generation, size of the colloids, or heavy metal generation within a time step. Generally, colloid size appeared to increase during the course of the experiments and greater concentrations of heavy metals were generated with increasing duration of each rainfall event.
DE: 1045 Low-temperature geochemistry
DE: 1831 Groundwater quality
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2003 Fall Meeting