The Mahanoy Creek Watershed filed a petition requesting that EPA perform an investigation at the Ellengowan-Knickerbacker Site (Site). The Ellengowan–Knickerbocker Site is located in the Mahanoy Creek watershed in Schuylkill County, near Frackville, PA. Following the burning of coal by local cogeneration plants, coal ash was placed at various locations at the Ellengowan Mine (including the Knickerbocker
Demonstration Site within this mine) and the BD Mine. The site encompasses these locations as well as the associated aquatic habitats that may receive hazardous substances, pollutants or contaminants released from the mines collectively. The surface area of the two mines comprises approximately 4600 acres. Since 1988, approximately 16 million tons of coal combustion waste has been disposed into four
pits in the Ellengowan and BD Mines. The waste was primarily fluidized bed combustion ash generated from burning locally-derived waste anthracite coal in the Gilberton and Schuylkill Energy Resources Cogeneration Power Plants. Combustion ash from bituminous coal (not of local origin) has also been placed in the area. Directly underneath the four pits are a series of interconnected mine pools flowing from the collieries of underground mines historic to this area. They are the Tunnel Ridge, Boston Run, Saint Nicholas and Gilberton Collieries under the BD Mine, and the Indian Ridge, Shenandoah City, Knickerbocker, North Mahanoy, Mahanoy City, Maple Hill and West Shenandoah Collieries under the Ellengowan Mine. The predominant direction of water flow in the mine pools draining these collieries is from the northeast and east to the southwest and west, according to information in the permit files for the Ellengowan and BD Mine. The objective of this project was to evaluate the potential impact of coal ash placed at the mine and mine discharges on the ecosystem at the site. The field investigations included sampling of surface water, groundwater, sediment pore water and sediment. In addition, sediment toxicity testing and surveys of the benthic macroinvertebrate and fish communities were performed.
Surface water quality was evaluated at 20 sampling locations including two reference locations. This project included the collection and evaluation of aquatic environmental samples. Surface water,
groundwater, sediment pore water, and sediment samples were collected for analysis of site-related COPCs. Hydrologic data were collected at several pre-determined locations along Mahanoy Creek using piezometers to determine whether the Creek is a groundwater discharge or recharge area. Bulk sediment samples were composites of samples collected from depositional areas within the stream bed. Solid-phase sediment toxicity tests using Hyalella azteca were conducted for the sediment samples collected at all locations.
The results from this study suggest that a number of ecological risks exist in the Mahanoy Creek watershed. Higher concentrations of several metals, especially B, Mn and Fe in surface water, sediment pore water, and groundwater are detrimental to aquatic organisms. The strong acidic
environment at several locations is also detrimental to the aquatic organisms. Higher concentrations of metals, especially Mn, in mine discharge waste may be the source of elevated Mn concentrations
in surface water and sediment. The increase in water pH downstream of the Mahanoy Creek may be the indication that coal ash placed on the site has impacted the habitats. However, the results from this study cannot conclude the exact cause of the problem. One or all the ecological risks outlined above may have collectively impaired the ecosystem and caused the lack of fish and benthic macroinvertebrate communities in the Mahanoy Creek watershed. No further action will be taken by EPA. Notification letters were sent to the land owners who provided access to EPA to conduct this study, and to the Mahanoy Creek Watershed to inform them that the site is closed and no further action will be taken. A copy of the final report was included with the letter.
- Due to the magnitude of impact a Removal Investigation was performed
- A comprehensive ecological study was conducted at the request of the Mahanoy Creek Watershed Association
- The results of the study show degradation to the Mahanoy Creek to be present, however the data is not conclusive to the source.
- EPA has circulated the study report to all property owners who gave EPA access.
- EPA will transmit the report to PADEP and OSM
- EPA Removal Program does not plan any additional study to be conducted at this time.
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