Acid mine drainage (AMD) from an underground coal mine in the Jones Branch watershed in McCreary County, KY, substantially reduced water quality in Jones Branch. Downstream from the mine seeps, the pH was routinely below 4.5 and concentrations of most heavy metals, especially iron, were elevated. A cattail wetland (1,022 m2) was constructed on Jones Branch in 1989 to obviate the effects of the AMD. Monthly chemical monitoring was performed on the water from above, from below, and from the 26 cells within the wetland. Based on chemical monitoring, the wetland initially improved water quality, increasing the pH and removing substantial amounts of heavy metals. Beginning in the spring of 1991, water quality at the wetland outfall began to decline, and has not improved to date. To augment the chemical monitoring, a biomonitoring study was initiated in the spring of 1990. Acute 48-hr static tests were conducted with newly hatched fathead minnows (Pimephales promelas). Water samples were obtained from the seep inlet, four cells within the wetland, and from Jones Branch above and below the wetland site. Median lethal concentration (LC50) values determined monthly reflect the decline in water quality at the outfall over time. However, within the wetland there was gradual improvement in survivability from inlet to outlet, providing evidence that the wetland was responsible for a modest improvement in water quality.
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The work upon which this report is based was supported in part by funds provided by the United States Department of the Interior, Washington, D.C. as authorized by the Water Resources Research Act of P.L. 101-397.
Ramey, Barbara A.; Halverson, Howard G.; and Taylor, Linda A., "Biomonitoring Study of a Constructed Wetland Site Treating Acid Mine Drainage" (1992). KWRRI Research Reports. 23.