Ion exchange and soil attenuation of Gulf Coast and Great Plains soils: Final report

Abstract

There are many trace elements, including arsenic, selenium, and molybdenum, which can occur in significant concentrations in ash from low-rank coals. These elements have the potential to be leached from disposed ash and returned to the environment. As coal-waste leachates from disposal sites come into contact with surrounding sediments, these sediments can have a pronounced effect on concentrations of dissolved trace elements in the leachate. This project was designed to measure and characterize the trace element attenuation properties of overburden sediments from Texas, Montana, and Wyoming. The project began with a previous study of pH buffering and trace element attenuation properties of North Dakota sediments. The initial study provided much essential information and insight into possible mechanisms of trace element attenuation. In addition, this initial research provided us with an established experimental protocol with which to conduct studies on pH buffering and trace element attenuation properties of near surface overburden sediments. The samples used in this study were obtained from test holes drilled to a maximum depth of 100 feet. The resulting samples were evaluated with respect to their ability to buffer pH and attenuate trace elements using the techniques developed during the North Dakota phase of the project. 37more » refs., 18 figs., 24 tabs.« less