“No imminent hazard to human health or the environment has been identified.”
That is the key finding in a comprehensive site assessment of the Belews Creek Steam Station ash ponds conducted by HDR Engineering, Inc.
The report, released last Thursday, was commissioned by Duke Energy as required by recent coal ash legislation.
The study involved borings and installation of monitoring wells at and around the ash basin as well as collection of soil, groundwater, seep and surface water samples.
While the initial finding indicates the existing ash basins pose no immediate threats, it does identify a number of areas where some seepage is occurring.
According to the report, the area around the ash basin has several naturally occurring constituents including antimony, iron, manganese, pH and vanadium. In addition to those constituents, the EPA uses indications of boron, TDS and chloride to indicate the impact that ash ponds can have on groundwater.
The report notes that at Belews Creek, boron exceedances were present within the the basin’s compliance boundary in shallow and deep flow water layers, but there were no exceedances within the deep or bedrock flows.
TDS exceedances were found both in shallow and deep flow areas within the compliance boundary and in the deep flow areas immediately west of the basin and near Middleton Loop Road outside of the compliance boundary.
“This indicates groundwater flow through the northwestern rim of the ash basin toward the Dan River,” reads the report. “The seeps may represent preferential flow paths. This flow direction is away from the direction of the nearest public or private water supply wells.”
The North Carolina Department of Energy and Natural Resources has tested seven off-site private water supply wells in 2015, resulting in a decision by the North Carolina Department of Health and Human Services to recommend that five of the sampled wells not be used for drinking water due to the presence of one or more constituents including iron, vanadium and chomium, but the recent report notes those constituents are naturally occurring in the area.
The report notes that there are still several data gaps for the area, recommending the installation of additional groundwater monitoring wells to fully understand the horizontal extent of concentrations of impacted groundwater west and down gradient of the ash basin dam.
Although the report says there is no imminent hazard to public health from the basin, it does suggest corrective action to address the identified soil and groundwater contamination in certain areas.
“It is generally limited to within the ash basin compliance boundary, with the exception of the area impacted west of the ash basin dam and Middleton Loop Road,” reads the report’s conclusion. “The source and cause of impacts from boron, and TDS that is associated with elevated levels of chloride… is the coal ash contained in the ash basin. The cause of contamination… is leaching of constituents from the coal ash into the underlying soil and groundwater. However, some groundwater, surface water and soil standards were also exceeded due to naturally occurring elements found in the subsurface, including antimony, cobalt, iron, manganese, pH and vanadium.
“The human health and ecological screening-level risk assessments did not specifically identify the presence of health or environmental risks; however, the results indicate that constituents in environmental media could be of concern and further investigation by a site-specific risk assessment may be warranted,” adds the report.
The full report can be found online at www.duke-energy.com/ash-management/groundwaterstudies.asp.
Nicholas Elmes may be reached at 336-591-8191 or on Twitter @NicholasElmes.