English

Abstract

The demand for natural gas is increasing due to the global energy crisis. Due to the demand for natural gas there have been major explorations in the Rocky Mountain States. One of the largest areas for natural gas extraction is the Powder River Basin, Wyoming. The process of extracting natural gas involves pumping water from coal seam aquifers that is mixed with the natural gas. Once the water and gas reach the surface they are separated and product water is disposed into a nearby disposal pond. The objectives of this study were to monitor water quality components, model the components in a water quality model, and monitor trace metals in the sediments of the disposal ponds. Samples were collected and analyzed for major cations, anions, and trace metals. Results from one year of sampling suggest wide ranges in pH, oxidation reduction potential, electrical conductivity, temperature, and dissolved oxygen. Concentrations for sodium were high when compared with the concentrations of the other major cations. Practical sodium adsorption ratios calculated from the concentrations of sodium, magnesium, and calcium ranged from 6.3 to 51.86. True sodium adsorption ration calculated from the activities of sodium, magnesium and calcium ranged from 7.07 to 88.05. The highest concentration of trace metals in both wells and disposal ponds were barium and boron. Sediment samples were also collected and a Toxic Characteristic Leaching Procedure was preformed to determine leachability and toxicity of trace metals. The two trace metals detected in sediment leachates were barium and manganese. When compared to groundwater drinking water standards both barium and boron concentrations in sediment leachates were above the limits.