Have you heard of “halogenated hydrocarbons”? It is a group of chemicals containing elements that when consumed by humans, it can damage the nervous system and your liver. Normally, these compounds are not on your daily menu. But studies suggest these elements are appearing in water as by the reuse of fracking wastewater which ironically has been treated with chlorine-containing antibacterial chemicals. The process of cleaning the water is a common practice. More studies of treated wastewater are being conducted to more clearly determined if the creation of halogenated hydrocarbons from antibacterial chemicals occurs during treatment of wastewater or during reuse.
Produced water, water that is chemically cleaned, can contain a complex mixture of metals — salts and other chemicals, partly composed of the original fracturing fluid components — plus chemicals released by the rocks in the area. Large volumes of water used for fracking poses some level of side effects of the wastewater on human and environmental health. To investigate further, researchers in Europe, in one of the most comprehensive studies of chemical composition of its kind to date, took samples of produced water from three fracking sites in the US. A number of different analysis techniques were used to determine the chemical composition of the samples, although not the concentrations of the different organic (carbon-based) constituents.
The researchers found that produced water contained a diverse array of chemicals including toxic metals such as mercury and the carcinogens toluene and ethylbenzene. However, a group of harmful chemicals, ‘polyaromatic hydrocarbons’ commonly found in mining and coal extraction wastewater, were absent.
A wide range of metals were found in all samples, but varied depending on the geology of the area. Among these were chromium, mercury and arsenic, all of which were found at levels exceeding US maximum contamination levels (MCL) for drinking water in at least one well. Over 50 different organic chemicals were identified, the majority of which were part of a group of chemicals called ‘saturated hydrocarbons’. Many of these were common to more than one well. They included carcinogens toluene and ethylbenzene. However, the researchers did not find polyaromatic hydrocarbons, which are usually found in mining and coal extraction wastewater.
The authors believe that detailed chemical analyses of produced waters, such as theirs, highlight problems in wastewater treatment protocols, In particular, the problem of developing a process that removes a wide range of organic compounds. While the findings of this research are based on fracking sites in the US, they may also be useful for other regions where fracking is being actively pursued, such as the UK, and could help to develop policies and techniques to reduce the risk of environmental contamination.
Fresh water continues to be challenged, not from just drought or salt contamination, but from the process of re-creating quality drinking water.