Scientists at Stony Brook University have determined that the disposal of wastewater from hydraulic fracturing is one of the largest potential risks for water pollution. The study was done in the Marcellus Shale region where wells are hydraulically fractured in order to obtain natural gas.
Hydraulic fracturing, more commonly known as fracking, occurs when fluids are pumped underground into shale formations. The pressure from the fluids releases pockets of natural gas, which is then pumped back to the surface and captured. The Marcellus Shale is one of the largest of its kind, covering 12,400 square kilometers from New York to West Virginia.
The study, entitled “Water Pollutions Risk Associated with Natural Gas Extraction from the Marcellus Shale”, is published in the August 2012 issue of the journal Risk Analysis. It was conducted and written by Daniel Rozell, P.E., a Stony Brook doctoral student, and Sheldon Reaven, Ph.D., a professor at the university. They found that “Even in a best case scenario, an individual well would potentially release at least 200 m3 of contaminated fluids.”
The methods of the research involved comparing potential water pollution pathways stemming from fracking for natural gas. Disposal of fracking well wastewater was found to contain risks from salts and other radioactive materials that are far larger than the other studied pathways. The Environmental Protection blog stated that these other pathways include “a tanker truck spilling its contents while transporting fluids used in the drilling process going to or from a well site; a well casing failing and leaking fluids to groundwater; fracturing fluids traveling through underground fractures into drinking water; and drilling site spills at the surface caused by improper handling of fluids or leaks from storage tanks and retention ponds”.
Wastewater disposal can lead to higher pollution levels in rivers and streams. According to the researchers, this is because the treatment facilities that the wastewater is sent to “are not designed to handle hydraulic fracturing wastewater containing high concentrations of salts or radioactivity two or three orders of magnitude in excess of federal drinking water standards”.
The researchers go on to say that “Any drilling or fracturing fluid is suspect for the purposes of this study” because “even a benign hydraulic fracturing fluid is contaminated once it comes into contact with the Marcellus Shale.” They believe that “regulators should explore the option of mandating alternative fracturing methods to reduce the wastewater usage and contamination from shale gas extraction in the Marcellus Shale.” In conclusion, the authors feel that “future research efforts should be focused primarily on wastewater disposal and specifically on the efficacy of contaminant removal by industrial and municipal wastewater treatment facilities.”