So why has fracking been met with so much opposition? For one, citizens in towns where fracking is actually taking place have been scared by reports of methane contaminations in their water supplies. Though it is hard to conclusively determine the root cause of these methane leaks, fracking could provide a potential explanation.

Many fracking sites, including the Marcellus Shale region, lie under watersheds which are used to supply drinking water to local towns. In order to reach this region, workers build casings around the regions they drill to reach the natural gas deposits. Drilling through this aquifer region is clearly outlined in the image below:

Problems arise when these casings are not sealed properly. Holes within these seals enable gases to leak out and may explain the methane contamination of within local water supplies.

An initial study in 2011 looked at methane concentrations in 68 drinking water wells at varying distances from fracking sites in the Marcellus Shale region. They found that “methane contamination rose sharply with proximity to natural gas drilling and hydraulic fracturing.” Interestingly, however, when this type of study was repeated in 2015 in 11,309 drinking water wells within the same region, there was found to be no significant differences in methane concentrations based on proximity to the tracking site. Conflicting studies such as these two are continuing to surface making it difficult for scientists to develop a firm stance on fracking’s impact on local water supplies.

Sources:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2866701/

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3222989/

http://www.sciencemag.org/news/2015/03/methane-drinking-water-unrelated-fracking-study-suggests