Groundwater contaminated by fracking

Study: Drinking water contaminated by leaking drill holes during fracking

09/16/2014

In many countries of the world there are great reservations about fracking. This method, which is used in natural gas production, has already contaminated the groundwater in some places. According to researchers, the contamination originates from leaks at the gas wells and could be remedied technically. The concerns about a possible health hazard remain.

Contaminants go back to leaky holes
Apparently, the contamination of the drinking water due to fracking usually go back to leaky holes. Like a research team around Thomas Darrah from Duke University in Durham (US state of North Carolina) in the journal „Proceedings“ the US National Academy of Sciences („PNAS“) is reported to be the blasting of the rock in the depth usually not responsible for the pollution. The researchers had analyzed a total of 133 drinking water samples from two production zones in the states of Pennsylvania and Texas. They found in eight sample groups increased concentrations of hydrocarbon compounds such as methane. The scientists emphasized that most problems could probably be remedied technically.

Mixture of water, sand and chemicals
In fracking, rock is broken up at great depth under high hydraulic pressure, with normally a liquid mixture of water, sand, and chemicals first being channeled through wells and pressed horizontally into the respective target layer. This causes cracks in the rock, through which gas can escape and then be transported with pipes through the borehole to the surface. As the researchers write, knowledge about the contamination can be „to improve the environmental and economic sustainability of shale gas production“ to lead.

In France, a fracking ban applies
The use of the procedure is also being discussed in Germany and many other countries. In the US, fracking has been practiced for a long time, and already accounts for one-third of total natural gas production. France, on the other hand, has officially prohibited the controversial natural gas production. It was thus the world's first country with a fracking ban. Critics fear that fracking could pollute the drinking water with hydrocarbon compounds or other chemicals. In Germany, among other things, the State Medical Association of Baden-Württemberg in the past has warned in this context: „Contaminated drinking water endangers the health of our population.“ Even though it has apparently been clarified by the new study from the USA, how such substances get into the groundwater: The fear of possible health hazards should not be eliminated with most people.

Gases can ascend hundreds of meters through the borehole
In the study, the US researchers analyzed in 2012 and 2013, a total of 113 samples of drinking water sources from layers far below the groundwater level. Among other things, the samples were analyzed for certain noble gases, the concentration of which gives information about the origin of the substances. „Our data found eight groups of sources - seven in Pennsylvania and one in Texas - contaminated, including elevated levels of natural gas from the Marcellus Formation in Pennsylvania and shallower middle strata in both states“, Darrah explained in a statement from his university. „Our data clearly show that the contamination of these groups is due to problems with the integrity of the wells, such as poor plating and concreting.“ The gases can thus ascend hundreds of meters through the borehole and then enter the groundwater layer.

Drinking water quality deteriorates
In Texas, the scientists testified how the drinking water quality deteriorated. „The water of the people was damaged by the drilling“, so co-author Robert Jackson. „In Texas, we even saw two homes initially contaminate clean drinking water after we started our study.“ Probably, however, none of the impurities were caused by the actual breaking up of the rock in depth, but they were connected to the respective borehole. According to the researchers, most problems could be prevented in the future. However, studies must clarify whether the large volumes of water that are being squeezed under enormous pressure can damage the lining of the boreholes. The conclusion of the scientists: „Borehole integrity is a crucial, feasible, and cost-effective way to reduce problems with drinking water pollution and mitigate public concern about fracking.“

Many experts demand a complete ban on fracking
According to a study by the German Federal Institute for Geosciences and Natural Resources (GBR), shale gas reserves in Germany amount to around 13 trillion cubic meters of bound gas in claystone, of which about 10 percent is recoverable according to the current state of the art. This is significantly more than is currently stored in conventional natural gas reserves. Due to the feared environmental consequences, there is also considerable resistance to fracking in Germany. The Federal Environment Agency (UBA) demands a rapid legal regulation of the technology. Fracking should in principle be prohibited in water protection and medicinal spring protection areas as well as other sensitive areas. An extensive risk assessment is to be carried out both before pilot drilling and before production wells. Nature conservation organizations and many other experts, however, call for a complete ban on technology. (Ad)