Surface and groundwater contamination associated with modern natural gas development
Author: Physicians Scientists & Engineers for Healthy Energy
PSE* published the original article in March 2014. Republished on SHIP with permission.
Published: July 10, 2014
Documentation of water contamination associated with modern natural gas development is a complex issue. The list of studies reported here [PSE science summary] should be seen as conservative and limited reporting of water contamination, as it only contains evidence from peer-reviewed scientific studies and does not include incidences that exist in inspection records.
Differences in local geologies and hydrologic characteristics, land-use histories, industry practices, and monitored water contaminants can complicate comparisons across studies. Baseline conditions for water quality are often unknown or may have been affected by other activities. Nonetheless, empirical evidence of surface and groundwater contamination as a result of modern natural gas operations is documented.
Pennsylvania (Marcellus). Several studies indicate degradation of ground and surface waters in dense drilling areas of Pennsylvania. Studies1,2 found significantly higher concentrations of thermogenic methane in private water wells within 1km of one or more natural gas wells (6 and 17 times on average, respectively).
An examination of water chemistry and isotope signatures3 of effluents from a brine treatment facility, stream sediments near the discharge site, and surface waters downstream and upstream of the discharge site showed elevated levels of chloride and bromide in downstream waters consistent (combined with isotopic data) with produced-waters from Marcellus shale wells. Radium-228/Radium-226 ratios in downstream waters and near source sediments also closely matched ratios measured in Marcellus wastewaters. Radium-226 concentrations in near-source sediments (544-8759 Bq/kg) were found to be approximately 200 times greater that upstream and background sediments and in excess of U.S. radioactive waste disposal threshold regulations.
Texas (Barnett). A study of groundwater quality in the Barnett shale, TX4 revealed significantly higher levels of heavy metals (strontium, selenium, arsenic) in private water wells located within 2km of active gas wells relative to private wells located further from drilling activity. This study was unique in that it used historical data from the region to create a baseline measure of groundwater quality before the expansion of natural gas operations. Arsenic, strontium, and selenium concentrations were also found to be significantly higher in active drilling areas relative to this historical baseline. Shallower water wells near drilling activity showed the highest levels of contamination. These findings suggest that mechanical disturbance (i.e. subsurface vibrations) of water wells, surface spills and/or faulty well casings/cement as possible causes of contamination.
Kentucky (Appalachian). A release of hydraulic fracturing fluids to a Knox County stream resulted in fish stress and mortality. Water chemistry analysis5 of the impacted stream revealed elevated conductivity, lowered pH and alkalinity, and toxic levels of metals. Sampling of fish exposed to the contaminated water exhibited a high incidence of gill lesions consistent with impacts observed in fish exposed to low pH, dissolved heavy metals, or both. Among the species affected was the federally protected Blackside Dace.
Colorado (Denver-Julesburg and Piceance). An analysis of reported surface spills (Colorado Oil and Gas Conservation Commission, COGCC) within Weld County (Denver-Julesburg) and groundwater monitoring data associated with each spill6 revealed BTEX (benzene, toluene, ethylbenzene, xylene) contamination of groundwaters. During a one-year period the authors noted 77 reported surface spills impacting groundwater; 62 of these records included BTEX analytical sampling during remediation. A large percent of samples show BTEX concentration in excess of federal standards. Another study of surface and groundwater samples from drilling-dense areas in the Piceance basin7 showed higher estrogenic, anti-estrogenic, or anti-androgenic activities near oil and gas activity relative to reference sites with little or no natural gas developments.
References
1. Osborn, S.G., Vengosh, A., Warner, N.R., Jackson, R.B., 2011. Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing. Proceedings of the National Academy of Sciences 108, 8172-8176.
2. Jackson, R.B., Vengosh, A., Darrah, T.H., Warner, N.R., Down, A., Poreda, R.J., Osborn, S.G., Zhao, K., Karr, J.D., 2013. Increased stray gas abundance in a subset of drinking water wells near Marcellus shale gas extraction. PNAS, 1-6.
3. Warner, N.R., Christie, C.A., Jackson, R.B., Vengosh, A., 2013. Impacts of Shale Gas Wastewater Disposal on Water Quality in Western Pennsylvania. Environmental Science & Technology 47, 11849-11857.
4. Fontenot, B.E., Hunt, L.R., Hildenbrand, Z.L., Carlton Jr, D.D., Oka, H., Walton, J.L., Hopkins, D., Osorio, A., Bjorndal, B., Hu, Q.H., Schug, K.A., 2013. An evaluation of water quality in private drinking water wells near natural gas extraction sites in the Barnett shale formation. Environmental Science & Technology.
5. Papoulias and Velasco, 2013. Histopathological Analysis of Fish from Acorn Fork Creek, Kentucky, Exposed to Hydraulic Fracturing Fluid Releases. Southeastern Naturalist. 12, 92-111
6. Gross, S.A., Avens, H.J., Banducci, A.M., Sahmel, J., Panko, J.M., Tvermoes, B.E., 2013. Analysis of BTEX groundwater concentrations from surface spills associated with hydraulic fracturing operations. J Air Waste Manag Assoc. 63, 424-432.
7. Kassotis, C.D., Tillitt, D.E., Davis, J.W., Hormann, A.M., Nagel, S.C. 2013. Estrogen and Androgen Receptor Activities of Hydraulic Fracturing Chemicals and Surface and Ground Water in a Drilling-Dense Region. Endocrinology 155
*Physicians Scientists & Engineers for Healthy Energy examine the empirical bases and assumptions of unconventional energy production as well as the energy transition from fossil fuels to renewable energies by fact-checking and disseminating carefully vetted, peer-reviewed, evidence-based information to the public.
