The disposal of contaminated wastewater from hydraulic fracturing wells producing natural gas in the Marcellus Shale region presents risks from salts and radioactive materials that are “several orders of magnitude larger” than for other potential water pollution events examined in a report by Stony Brook University.
Other water pollution pathways studied in Water Pollution Risk Associated with Natural Gas Extraction from the Marcellus Shale 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 migrating 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.
In events from the worst-case 50th percentile wastewater disposal would release 13,500 m3 of contaminated water, a fracture migration – the next largest potential contamination event – in that percentile would release just 225 m3 of contaminated water, the report says. Even in a best case scenario, wastewater disposal from an individual well would potentially release 202 m3 of contaminated fluids, the report says.
As a result, regulators and other authorities should consider additional mandatory steps to reduce the potential of drinking water contamination from salts and naturally occurring radioactive materials, such as uranium, radium and radon from the rapidly expanding fracking industry, according to the report.
The new findings and recommendations come amid significant controversy over the benefits and environmental risks associated with fracking. The practice, which involves pumping fluids underground into shale formations to release pockets of natural gas that are then pumped to the surface, creates jobs and promotes energy independence, but also produces a substantial amount of wastewater.
In May, Chevron and ExxonMobil shareholders filed proposals asking the companies to disclose risks to their operations and finances from hydraulic fracturing. Shareholder advocacy group As You Sow filed the ExxonMobil resolution on behalf of the Park Foundation, while Sisters of St. Francis of Philadelphia and Green Century Capital Management filed the Chevron resolution. The organizations asked the oil and gas companies to disclose risks posed by regulations and moratoriums on hydraulic fracturing as well as by public opposition.