Within a few years, shale gas has made the US independent of imports, reduced natural gas prices, and supplied cheap raw materials for the chemical industry. At the same time, the concern about environmental contamination has led to controversial public discussions. The focus is on the chemicals that play a role in fracking.
Experts from the Gesellschaft Deutscher Chemiker (GDCh; German Chemical Society) summarize current gaps in knowledge with respect to the water chemistry involved in fracking.
Between 7 and 18 million liters of water are needed to perform a single fracking operation. A systematic review of the chemicals used is difficult owing to the large amounts that are used, the fact that many substances are a company secret, as well as the fact that substances that make up less than 0.1 % of the total do not need to be declared. A significant portion of chemicals used in fracking is, therefore, still unknown to the public.
It is not yet possible to reliably predict the release of problematic substances, or prevent this by optimizing the fracking processes. Gaps in knowledge exist, for example, concerning the mobility of organic compounds, heavy metals, and radioactive elements during hydraulic stimulation. Similarly, the microbiology occurring deep underground is still largely unknown.
At high temperature, high pressure, and high salt concentrations, fracking chemicals can undergo chemical reactions that are significantly different from those that occur in shallow groundwater. In addition, the redox conditions change during the fracking processes, because of the addition of oxidants and reducing agents. Therefore, geogenic substances may be converted into new products. Thus, potentially new organic products are formed underground.
Future research in this area is not only a scientific challenge, but crucially depends on the willingness of the industry to share information about fracking chemicals and to provide independent scientists access to current fracking operations.
The experts also think that a debate on cost versus benefits addressing questions like “Why is a substance used and not a more environmentally friendly alternative?”, would lead to an improved acceptance of the fracking process.
- Chemikalien beim Fracking zur Gewinnung unkonventioneller Erdgasressourcen,
Martin Elsner, Carsten Vogt, Anett Georgi, Frank-Dieter Kopinke, Wolfgang Calmano, Kathrin Schreglmann, Axel Bergmann, Bernhard Mayer,
Aktuelle Wochenschaue (GDCh) 16. April 2014.
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