Assessment of water quality in streams draining coal-producing areas in Ohio

Abstract

Quality of water in 150 sites in the coal-producing areas of eastern Ohio was studied in a two-phase investigation between May 1975 and August 1976. Results of phase one, a reconnaissance to determine the occurrence of certain inorganic and organic constituents and to relate their occurrence to coal mining, indicated that acid mine drainage generally occurred where abandoned drift or abandoned strip mines were located. Streams affected by such mines contained concentrations of dissolved sulfate and iron greater than 250 milligrams per liter and 5,000 micrograms per liter, respectively, and exhibited pH values less than 4.5. Areas characterized by reclaimed or active strip mines showed few instances of acid drainage (pH values were generally greater than 7.0). Iron concentrations in these regions generally were less than 500 micrograms per liter, with dissolved-sulfate concentrations ranging from 22 to 7,100 milligrams per liter. Phase two was a detailed study of four small basins sampled during the first phase and found to represent different types of mining. The objective was to determine whether water-quality degradation within the basins was due to coal mining. Flows from two basins, one containing abandoned drift mines and the other abandoned strip mines, became increasingly acidic (pH values less than 4.5) downstream, and had high iron and dissolved sulfate concentrations (above 5,000 micrograms per liter and 250 milligrams per liter, respectively). Sources of acidity were tributaries that drained directly from the mines. The other two basins, one containing reclaimed strip mines and the other active strip mines, exhibited no acidic drainage; streams in both basins had pH values greater than 7.0 and iron concentrations below 500 micrograms per liter. Presence of active surface mining seemed to have little effect on dissolved sulfate concentrations, as only streams in the reclaimed basin had high concentrations (usually over 2,000 milligrams per liter).