As the number of fracking sites increases with numerous new planning permissions for drilling being issued almost every day, the concerns over safety and water contamination trigger even more protests and debates.
Hydraulic fracturing, or fracking in short, is a technique of shale gas and oil extraction through injecting a mix of water, sand and chemicals deep into the earth. Although it is being advertised as a safe process with numerous economic benefits, fracking is also associated with a number of environmental concerns over contamination of drinking water, air quality and migration of pollutants to the earth surface.
A series of independent studies conducted in the U.S. aimed to examine whether the concerns over water pollution hold and there is really something that society should worry about.
The first one comes from a team of researchers at University of Texas in Arlington. The study was carried in the area of Barnett Shale, known to host around 16,000 active gas wells. After sampling drinking water from 100 of the privately owned wells, the team was able to identify increased concentrations of arsenic, selenium and strontium. The authors point out that the further from the fracking wells the sampling locations were, the lower the concentrations of the elements. In addition, the team also measured high concentrations of methanol and ethanol, which they explained with poor maintenance of the pipes.
Another study was conducted by researchers at Duke University. Carrying their sampling in the Marcellus shale basin in Pennsylvania, the team was able to identify high levels of methane in drinking water collected near the gas extraction sites. The authors claim that the reason for this is faulty casings on wells. These findings, or to be more precise, their interpretation, however was proven wrong by research carried by the US Geological Survey. Here the scientists sampled drinking water in the same area, but not in the region of the fracking sites, and also found high levels of methane, indicating naturally contaminated ground water.
There is no clear evidence that fracking poses risks to the environment, however it is also unclear whether there are no risks. This is especially important since most fracking wells are drilled through groundwater supplies.