Analytical Methods for the Comprehensive Characterization of Produced Water

Abstract During the unconventional oil and gas development stimulation process, referred to as hydraulic fracturing, millions of gallons of freshwater can be used, as well as the production of millions of gallons of wastewater with a highly variable, chemically rich composition. This waste stream can contain a mixture of organic and inorganic additives, transformation products, as well as inorganic and organic substances from the formation. Unfortunately, there is limited knowledge with regard to the composition of chemical additives used during hydraulic fracturing. Additionally, there currently do not exist any methods approved by the US regulatory agencies for the evaluation of produced water. Collectively, these two factors have led to significant knowledge gaps with respect to exposure, hazard data, and analytical methods. As a result, there is an inadequate understanding of the environmental and human exposure implications during contamination events. Furthermore, pursing a deeper understanding of the chemicals that could be present in produced water can provide valuable insight when monitoring the efficacies of various treatment technologies for the reuse of produced water. This chapter will discuss the analytical methods that have been used to evaluate five key constituent categories found in produced water: bulk measurements, organics, biological, inorganics, and naturally occurring radioactive material. In addition, the chapter will touch on the outstanding concerns and remaining knowledge gaps.