Surface water geochemical and isotopic variations in an area of accelerating Marcellus Shale gas development

• 50 streams sampled in an area of accelerating shale gas development.
• Study area has a long history of underground and surface coal mining.
• Geochemical and isotopic characteristics used to distinguish sources of salinity.
• Water chemistry in some streams seem to have been impacted by mine drainage.
• Synoptic sampling hence does not account for major/minor spills or mine discharges.

Water samples were collected from 50 streams in an area of accelerating shale gas development in the eastern U.S.A. The geochemical/isotopic characteristics show no correlation with the five categories of Marcellus Shale production. The sub-watersheds with the greatest density of Marcellus Shale development have also undergone extensive coal mining. Hence, geochemical/isotopic compositions were used to understand sources of salinity and effects of coal mining and shale gas development in the area. The data indicates that while some streams appear to be impacted by mine drainage; none appear to have received sustained contribution from deep brines or produced waters associated with shale gas production. However, it is important to note that our interpretations are based on one time synoptic base flow sampling of a few sampling stations and hence do account potential intermittent changes in chemistry that may result from major/minor spills or specific mine discharges on the surface water chemistry.