INVESTIGATING THE CONTROLS ON SALINIZATION OF RIVERS IMPACTED BY OIL AND GAS WASTEWATER DISPOSAL
Salinization threatens our freshwater by causing a domino effect of hydrogeological processes, such as increasing concentrations of dissolved radium, sulfates, boron, fluoride, and trace metals in our water. This study investigates increasing salinity in three tributaries to a major river basin in the western USA for impacts from permitted discharges of saline oil and gas produced water. Produced waters are discharged through national pollutant discharge elimination system permits (NPDES) and, in the arid West, beneficially used for irrigation and supply water for cattle, but downstream the river is a source of drinking water to the local community causing concern for continued discharge of saline water to the freshwater supply. Water samples were collected during twelve sampling events from 2013 to 2015 at 26 sites along the tributaries both upstream and downstream of NPDES permitted discharges. Statistically significant increases were determined for sodium, sulfate, chloride, and calcium downstream from discharges. Molar ratios (e.g., Na/Cl and Ca/SO4) were utilized to determine if the spatial and temporal increases in concentrations are explained by evaporation, dissolution of minerals, or low flow rates.
Bonnie McDevitt (Primary Presenter/Author), Pennsylvania State University, firstname.lastname@example.org;