Fracking for natural gas in parts of Pennsylvania with a legacy of energy extraction may increase the risk of groundwater contamination, according to a team led by Penn State scientists.
The researchers found a potential link between elevated levels of chloride in groundwater and areas where horizontal drilling and fracking for shale gas overlaps with a high density of older, conventional oil and gas wells and coal mining in southwestern Pennsylvania. The link was not observed in samples from northeast Pennsylvania, which also experienced the Marcellus Shale boom, but which does not have the same long history of intensive energy extraction.