Wednesday, February 19, 2020

USGS Study: No Statistically Significant Relationship Between Shale Gas Development And Stream Chemical, Benthic, Microbial Life Changes In State Forest Drilling Areas

The U.S. Geological Survey released study results of 40 chemical parameters and benthic and microbial life study of oil and gas operations in 25 small watersheds in State Forest lands over a two year period.
The study notes DCNR uses a “robust and comprehensive” lease agreement, special guidelines for best management practices, frequent inspections and a monitoring system to manage oil and gas development on state forest lands to ensure compliance, in addition to regular inspection and oversight activities by DEP’s Oil and Gas Management Program.
[Note: Typical leases do not incorporate the same protective measures as those found in DCNR’s oil and gas management program.]
The study noted releases of produced water into surface water and produced water have led to the accumulation of metals in freshwater mussel shells and are reported to cause changes in streambed microbial community structures.
Also noted was the fact other studies have shown significant effects downstreams from discharges from municipal and industrial wastewater treatment plants treating produced water and shale gas wastewater disposal facilities and from large spill events.
In addition, “A group of studies focusing on northwestern Pennsylvania have demonstrated changes in microbial community structure in watersheds with OG [oil and gas] activity when contrasted to similar watersheds without activity, and report that microorganisms capable of using components of produced water and methane are found in higher abundance in surface water and sediments in watersheds with OG activity than in those without.”
“This study hypothesized the existence of a quantifiable relationship between the intensity of disturbance from Marcellus Shale gas development and changes in water chemistry, microbial community structure, and macroinvertebrate community composition in headwater streams in the PASF [State Forest] system. 
“No quantifiable relationships were identified between the intensity of OG [oil and gas] development, water composition, and the composition of benthic macroinvertebrate and microbial communities. 
“No definitive indications that hydraulic fracturing fluid, flowback water, or produced water have entered any of the study streams were found. 
“However, the role of sedimentation related to increased traffic from OG development on unpaved roads, pipelines, and well pads as a stressor of stream microbiota was identified as an important relationship for further investigation.”
The study further concluded--
“Of the variables directly related to shale gas production used in constructing the sDII, the mass of drill cuttings, volumes of gas and water produced, and volumes of drilling fluid and fracturing fluid used had significant site-level relationships to community structure during the spring. 
“In addition, significant relationships were identified between changes in spring microbial community structure and Environmental Health and Safety Violations and Pennsylvania Clean Stream Law Violations. 
“The number and density of pipeline crossings had a significant relationship to changes in microbial community structure during the spring, but not the fall. 
“Runoff and sedimentation are higher during spring than fall in this region, and we hypothesize that the significant effects observed only during the spring may be a proxy for increased runoff and sedimentation from well pads, associated roads, road stream crossings, and pipeline stream crossings, given that we observed no indication of any geochemical or biological tracer of produced water in stream water or sediments. 
“Additional research is required to determine the validity of this hypothesis and to determine the role, if any, of other unassessed factors, such as road use related to non-OG activities.”
The study was funded by the USGS Toxic Substances Hydrology Program, USGS Environmental Health Mission Area, DCNR Shale Gas Monitoring Program and DEP.
Invaluable field support was provided by Anthony Haynie, Dale Gower, Shawn Lehman, Sharon Morris, Laurie Nau, Brett Pifer, Adam Benthem, Trout Unlimited Volunteers, and the staff of the USGS Northern Appalachian Research Laboratory.
Click Here for a summary of the study results printed the Proceedings of the National Academy of Sciences.
The Susquehanna River Basin Commission has done several studies of water quality impacts of oil and gas development in priority watersheds in State Forest and other lands, and found no adverse impacts. Click Here for more.
For more information on oil and gas drilling management on State Forest lands, visit DCNR’s Natural Gas Management webpage.
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[Posted: February 19, 2020]  PA Environment Digest

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