Harper, A. Mark, and Foos, A., 2000, Pennsylvanian aquifer systems in the Pottsville and Allegheny Groups, Stark County, Ohio. Geological Society of America Abstracts with Programs, v 32

ABSTRACT

Hydrologic units underlying Perry, Bethlehem, and Canton Townships of Stark County, Ohio, are found within Pennsylvanian aged rocks that are separated into two Groups. The older Pottsville Group consists of interbedded shales and sandstones along with thin, repeating sequences of limestone, coal, and underclay. Rocks of the younger Allegheny Group are similar in lithology to Pottsville units, but they contain thinner, less productive sandstone layers.
Chemical analyses of water samples collected from wells drilled to various depths indicate that four distinct hydrologic units are present in the area. Hydrologic unit #1, at an average depth of 70 ft, is classified as alkali-bicarbonate rich with an average TDS concentration of 475 ppm. Unit #2 yields a Ca-bicarbonate rich water at an approximate depth of 150 ft, with an average TDS of 363 ppm and sulfate concentrations of 48 ppm. Hydrologic system #3 yields a Ca-bicarbonate rich water from about 260 ft below the surface. Sulfate values ranging from 108-291 ppm in this unit are the greatest of all analyzed samples. TDS levels are also somewhat higher, reaching 534 ppm. Water from unit #4, at a depth greater than 400 ft, has an alkali-bicarbonate chemical composition. Samples from #4 have TDS levels exceeding 900 ppm, which is nearly twice that of the other systems. Chloride concentrations of some of these samples are over 300 ppm.
Chemical compositions of samples from hydrologic units #1 and #2 meet the United States EPA drinking water standards. Sulfate values in excess of 250 ppm are present in some samples from unit #3. These high sulfate concentrations, likely associated with Pennsylvanian coal beds, make the water unsuitable for consumption. EPA standards also recommend TDS levels to be lower than 500 ppm. Many of the samples from unit #3, and most of the samples from unit #4, exceed this limit.