Elevated Ba concentrations in a sandstone aquifer

Groundwaters of the Winnipeg Formation have been found to have Ba concentrations in excess of drinking groundwater guidelines over an area of several hundred square kilometers. Water samples are at or near barite saturation, however SO4 concentrations are exceedingly low. This inequality suggests that SO4 is being lost from the groundwater, allowing for a buildup of Ba in solution as barite saturation is maintained. The focus of this study is to investigate the relationship between Ba and SO4 and its application to anomalously high Ba concentrations found in the formation. These relationships are investigated through the use of transport modeling in PhreeqC. The model consists of the mixing two end-member waters that are found within the formation, reacting the mixed water with dissolved organic carbon, and transporting the newly mixed and reacted water through the formation.