ABSTRACT
The unsaturated soil zone (McCarthy and Zachara, 1989) is often assumed to act as a buffer for groundwater contaminants due to potential immobilization by sorption onto the soil matrix (Levin et al., 2002). However, waterdispersible colloid particles released from the soil matrix during rainstorm events can carry mobile and previously immobilized pollutants beyond this
CONTENTS
Introduction ......................................................................................................... 129 Case Study ............................................................................................................ 131
Soil Monolith Preparation ............................................................................. 131 Bulk Soil Analysis ........................................................................................... 132 Colloid Fractionation and Characterization ............................................... 132 In Situ Colloid Elution ................................................................................... 132
Findings ................................................................................................................ 133 Metal Concentrations in Bulk Samples ....................................................... 133 Adsorption Isotherms .................................................................................... 134 Metal Elution in Virginia Monoliths ............................................................ 135
Reclaimed Monoliths ................................................................................ 135 Spoil Monoliths .......................................................................................... 136 Biosolid Monoliths .................................................................................... 136
Metal Elution in Kentucky Monoliths ......................................................... 138 Reclaimed Monoliths ................................................................................ 138 Spoil Monoliths .......................................................................................... 139 Biosolid Monoliths .................................................................................... 140
Metal Associations ......................................................................................... 141 Concluding Remarks .......................................................................................... 144 References ............................................................................................................. 145
barrier (Seta and Karathanasis, 1997; De Jonge, Kjaergaard, and Moldrup, 2004). Reclaimed mine sites can be a source of heavy metals, derived either from the original unweathered spoil material or from industrial wastes, fertilizers, ˆy ash, or biosolids applied during various reclamation stages (Haigh, 1995). Unoxidized spoil materials can contain copper (Cu), lead (Pb), or zinc (Zn) sul”des (Geidel and Caruccio, 2000), while rock phosphate fertilizers can contain cadmium (Cd), chromium (Cr), iron (Fe), manganese (Mn), and lead (Pb) (Haigh, 1995).
