Hydrology of area 11, Eastern Coal Province, Ohio, Kentucky, and West Virginia

Investigation of Sources of Fluorinated Compounds in Private Water Supplies in an Oil and Gas-Producing Region of Northern West Virginia

“…Studies have shown that long-chain PFAS molecules adsorb more readily to soils and aquifer materials than short-chain PFAS. − Adsorption is particularly strong in the presence of high organic content materials, such as the interbedded shales and coal seams common in the Permian- and Pennsylvanian-age aquifer systems of the study region. − ,− All the PFCAs with carbon-chains of 9 or greater in this study have laboratory-derived organic carbon-normalized partitioning coefficients (log K oc ) greater than 2 L/kg, − which suggests their mobility within organic-rich aquifer materials would be limited. Partial degradation of long-chained PFAS under anaerobic or aerobic conditions is possible, though generally considered slow in comparison to adsorption .…”

“…The study area, which covers parts of Doddridge, Marshall, Ritchie, Tyler, and Wetzel Counties, is predominantly rural and forested (76.7% deciduous forest; 8.4% mixed forest 8.4), with small pockets of development and an industrialized corridor to the west along the Ohio River (Figures and S1). Within this portion of the Appalachian Plateau Physiographic Province, flat-lying (∼6 m/km eastward dip) to gently folded sedimentary bedrock is interbedded with coal and includes oil and natural gas bearing formations. − An estimated 20,000 individuals in the study area are solely reliant on private water supplies for hygienic and drinking water purposes …”

Natural and Anthropogenic Processes Affecting Domestic Groundwater Quality within the Northwestern Appalachian Basin

“…Both C8 and C9 occurred exclusively in areas of active or abandoned coal mining operations, and concentrations of SO 4 , HCO 3 , Fe, and Mn in these samples increased significantly (Kruskal Wallis, p -value <0.01) with decreasing distance to active surface mining and abandoned underground mining operations. Coal mining in Ohio and West Virginia began in the early 1800s and continues to be a source of mine drainage to local streams and surface waters. ,− ,− ,− Known mine drainages in the western NAB may be acidic or alkaline depending upon the buffering capacity of surrounding aquifer materials, but nearly all exhibit high concentrations of sulfate, dissolved metals, and other trace elements released during pyrite oxidation. , …”

“…Aquifers within the study area are comprised of cyclic horizontal sequences of Permian- and Pennsylvanian-age fractured sandstones, siltstones, shale, limestone, and coal, which form repeated heterogeneous perched aquifer systems and crop-line springs (Figure S3). − Formations are generally flat-lying with a gentle eastward dip (∼6 m/km), and surface expressions grade from older Pennsylvanian Conemaugh and Monongahela formations in the northwest to younger Permian age materials (Dunkard formation) to the southeast. − Erosion has produced a steep rugged topography with deeply incised valleys. Extensive stress-relief fracturing beneath valleys provides pathways for faster groundwater flow. − Domestic-well yields in valley settings generally range from (3.1 × 10 –4 )–(3.8 × 10 –4 ) m 3 /s, whereas yields in upland areas vary between 1.2 × 10 –4 and 1.9 × 10 –4 m 3 /s .…”

“…Due to differences in hydrogeologic conditions, geologic provinces (e.g., the highly deformed Appalachian structural front in northeastern Pennsylvania as compared to the minimally deformed Appalachian Plateau to the west), and state regulatory frameworks for drinking-water protection, it is reasonable to expect that groundwater vulnerability to contamination from UOG may differ between the eastern and western portions of the NAB. − Moreover, the portions of Ohio and West Virginia that now host UOG extraction have supported extensive surface and subsurface coal mining and conventional oil and gas (COG) development for more than a century. Coal mine discharges have raised concentrations of iron, manganese, sulfate, and toxic metals in the surface waters of the region. ,− As many as one in five streams in West Virginia have been degraded by coal mining operations, while 1300 miles of streams and rivers in Ohio are formally recognized as impaired. , Similarly, leaks from abandoned COG wells have been cited as potential sources of organic contaminants, heavy metals, brines, and iron to streams and rivers. ,, That these polluted surface waters are hydraulically connected to groundwater suggests that residential water wells may be at risk of contamination by coal mine discharges and COG, although observations appropriate for evaluating these risks are scarce.…”