WINSTON-SALEM DEALS WITH FLY ASH AT CITY YARD
Five years ago when the city of Winston-Salem began to conduct an environmental assessment of a site off of City Yard Drive that would house a future storm water treatment facility, they discovered something toxic. Large amounts of fly ash were found in the southern portion of the site, measuring four to eight feet in thickness. Fly ash is a byproduct of coal combustion and is not always dangerous to the public, but in this case chemical analysis showed that it contained a number of toxic chemicals including arsenic and lead.
The city has entered into an agreement with Griffith Enterprises, Inc. to carry out Stage four of an environmental assessment at a cost of $142,482.
Keith Huff, director of storm water and erosion control for the city, said when the city purchased 4.26 acres from the Winston-Salem Federal Credit Union they discovered the fly ash and other contaminants.
“There was diesel fuel in the groundwater, and there was also lead contamination from disposed lead acid batteries on the site,” he said.
While the city undertook a fuel recovery effort, the state’s Inactive Hazardous Sites Branch of the Division of Waste Management began lead remediation work of the credit union property as well as neighboring Central Park. Several crushed battery casings were found to be the source of the lead poisoning.
The next phase of the environmental assessment will involve placing the site under deed restriction and bringing the soil to a state in which it meets state industrial standards set by IHSB.
“In this case we will remove the fly ash that exceeds the industrial standard goals and then we will put that parcel of property under a deed restriction,” Huff said.
Huff said at this point there is no active project on the site and no danger to any of the surrounding community. Most of the fly ash is either encapsulated or will be removed, Huff said.
“We’ve taken samples of the underlying soil and have not found those pollutants of concern in the underlying soil and in the groundwater so that’s one silver lining about the efforts today,” he said.
Huff added that the city has hired an industrial hygienist who specializes in the transportation of fly ash. Wash down stations have been installed for employees at City Yard in preparation for the work.
Huff said around the same time the fly ash was discovered at City Yard, the material was also found under Research Parkway as part of a separate project.
“We were doing the central district pond and the northern portion of the Research Parkway that connects to the Salem Creek Connector when basically grading activities ensued,” he said. “There was a lot of cut zones in the southern part of that job, and they discovered fly ash then.”
Huff said this site has a Brownfields Agreement and to rid the area of fly ash the city worked with the division of waste management to encapsulate it and haul some of it to the public works facility on Lowery Street.
Phase four of the environmental assessment will help workers determine whether the fly ash can be capped and covered or whether there are hot spots that need to be removed in order to ensure the soil meets industrial standards.
Assistant City Manager Greg Turner said the fly ash under the soil dates back to the 1920s but it has only been recently that soil testing has been done there.
“The standards change. The testing for underground soil contamination became more refined,” he said. “Now you go in and look for the locations where that type of material was disposed of.”
Turner said the required cleanliness of the soil is generally 10 percent of what it needs to be for residential purposes. He said this has to do with the degree to which the public makes contact with the soil.
“You’re not interacting with the soil in an industrial environment,” he said. If it’s a playground or a park you’re directly interacting with the grass that’s in that soil.”
Cathy Akroyd, a spokeswoman with the North Carolina Department of Environment and Natural Resources wrote in an email that fly ash is detected by drilling borings into the ground to obtain information about the materials below the surface.
“Separation between soil and fly ash is identified as part of this process as soil is orange-brown and fly ash is dark gray,” she wrote. “Samples are collected for laboratory analysis to determine what contaminants may be present.”
Akroyd said the fly ash was not mixed with the soil and appears to have been found in low-lying areas. She confirmed that this poses no risk to groundwater and added that it is now safe to build a storm water facility there.
Turner said the main area of concern is in front of the gas pumps, but the entire site has yet to be analyzed according to a map from the city. City Yard lies just above the Salem Creek Greenway and future Salem Creek Connector site, but Turner said there is no danger posed to these areas.
“The connector is built on all fill material, so it’s piled dirt on top of the bad soil and so they’re separated by the new dirt it’s putting in,” he said. “The connector didn’t actually expose any of the bad soil.”
City yard is home to a host of operations that include fleet and traffic maintenance, sanitation and vegetation management.
Huff said the city will perform a chain of title search as part of the next phase of the project in order to determine which other areas, if any, are affected. He said IHSB would contact neighboring communities if need be.
“They would have the purview and the authority to reach out to those various entities that may or may not be what we call the RP, the responsible party,” he said. !