So what exactly is the fluid injected into these wells composed of? Fracking fluid is roughly 90% water, 9.5% sand and 0.5% chemical additives. These chemicals are added to prevent erosion of metal pipes, reduce friction, maintain fluid viscosity and stop microorganisms from growing within the pipes. The sand is added to hold fractures open. But when considering the large volumes of water used within fracking jobs it is important to note that this seemingly tiny 0.5 percentage can equate to 80-300 tons of chemicals per frack.
The “cocktail” of chemicals added varies from site to site but there are roughly 600 chemicals used worldwide and approximately 50 used in the Marcellus Shale region. Just some of the chemicals used and their purpose are outlined in the image below:
These chemicals include some volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene and xylene along with organic acids, hydrogen sulfide and various naturally occurring radioactive elements such as radium and uranium. Long term exposure to chemicals such as VOCs can lead to an increased risk of cancer, liver damage, kidney damage and central nervous system damage.
Why does it matter that these chemicals are used in fracking? In order to get to the Marcellus Shale rock formation workers must drill through an aquifer. This aquifer is an important source of groundwater for the region and supplies a large portion of water to the local towns. In order to drill through the aquifer workers are required to build a well casing to prevent the flow of fracking fluid and natural gases to the surrounding groundwater. A well casing is made by inserting a steel pipe into a borehole and cementing it into place. Leaks/short cuts taken in building these well casings may enable fracking fluid and natural gases to leak out of the pipes and contaminate these aquifers and consequently pollute local water supplies.
Sources:
http://www.nature.com/nature/journal/v477/n7364/abs/477271a.html
https://www.epa.gov/hydraulicfracturing
http://www.health.state.mn.us/divs/eh/indoorair/voc/
