CHEMICAL CHARACTERIZATION OF AMD WATERS AND SEDIMENTS AT ABANDONED COAL MINES OF SOUTHEASTERN OHIO

Acid mine drainage (AMD) is a serious environmental problem around SE Ohio. Overall, there are three main cations that contaminate waters in southeastern Ohio: iron, aluminum, and manganese. Iron is the major heavy metal and it is always the most abundant of the three, with variable concentrations of aluminum and manganese. Some watersheds have abundant rock alkalinity due to the presence of carbonate rocks, and calcium can be also an important cation in the water and sediments. The abundant precipitates that form in acid mine waters is of great concern because even if the waters are remediated with the addition of alkalinity, the bottom of the streams is covered with the fine precipitates, which are formed mainly by iron hydroxides. These fine sediments do not allow a full recovery of remediated AMD impacted streams. The need to separate these sediments from the stream and use them in some industrial application is evident. Sediments and water samples were collected at four different acid mine drainage sites in SE Ohio. These sites have contrasting chemical composition in terms of the ions Ca, Fe, Mn, and Al. In this work, we present the chemical characterization of sediments deposited in the four types of waters: waters with relatively low Al, Mn, and Ca and high Fe, waters with high Al that show higher water-rock interaction, waters with high Mn, and waters with high Ca and neutral to alkaline pH that reflect the presence of carbonate rocks in the watershed. Preliminary results suggest that the sediments with higher concentrations of heavy metals are those deposited from alkaline waters high in Ca.