Where Does Natural Attenuation Occur?
University of Oklahoma and USGS scientists used a combined microbiological and geochemical approach to identify the important processes occurring in the aquifer contaminated by leachate from the Norman Landfill (Cozzarelli and others, 2000, Harris and others, 1999). The combined sciences of microbiology and geochemistry are called biogeochemistry. The Norman Landfill researchers identified zones in the leachate plume at Norman Landfill where different biogeochemical processes are occurring. One method to identify different biogeochemical zones is to measure the concentration of certain chemicals and minerals, those that are involved in biogeochemical processes, in the ground water and in the aquifer. Electron acceptors are minerals or chemicals that can occur naturally in aquifer solids or ground water, such as iron oxides in the sediments or sulfate dissolved in ground water. These chemicals are called electron acceptors because microorganisms transfer electrons to them during respira
