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Wednesday, 21 December 2016 11:48

Lead contamination prompts permanent monitoring at SCC

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Simply removing contaminated dirt from the Southwestern Community College shooting range won’t be enough to close out a lead removal project that’s been in the works since April 2014, the N.C. Department of Environmental Quality announced this month. 

The DEQ is asking SCC to install four monitoring wells and a sediment retention pond on the site, with soil testing and sampling to be continued on a permanent, ongoing basis.

“The lead levels did come back high, so that’s not something that we expected to see after having removed so much of the contaminated soil,” said Jamie Kritzer, public information officer for the DEQ. “Anytime that happens you want to move with an abundance of caution to make sure you’re doing everything in the best interest of protecting public health and the environment.”

Lead cleanup on the shooting range began after an April 2014 funding request for shooting range upgrades led to the disclosure that an estimated 60 tons of lead had accumulated in the berm at the end of the 30-year-old range. The range sees heavy use from law enforcement professionals and students for training and qualifying activities. 

While lead remediation is not required on shooting ranges that are still in active use, testing revealed lead concentrations as high as 73 times the amount considered safe in an area downhill from the range. 

The plan was to remove the contaminated soil, treat it for disposal and haul it away. SCC contracted with the environmental consulting firm ECS Carolinas to oversee the project and Salisbury-based Containment Control, Inc. to treat and remove the soil. This fall, an estimated 350 tons of soil were excavated and disposed of in a Charlotte landfill, taking about 5 feet off the surface of the affected area.

But follow-up testing showed that, while the soil excavation had significantly reduced the level of lead contamination, concentrations were still high — about 10 times the concentration considered acceptable. 

With the Tuckasegee River flowing just downhill from the range, the DEQ thought it best to take those still high levels seriously. 

“What we’re attempting to do is get more and better information about where this lead contamination may be moving,” Kritzer said. “In other words, does it present any kind of concerns to the nearby Tuckasegee River? If there’s runoff from the site, does it present any kind of groundwater concerns if there are well users down-gradient? It’s just sort of being as safe as we possibly can.”

Generally speaking, lead contamination doesn’t spread easily. It tends to bind with the soil and resists degradation. However, when concentrations get too high water can drive lead particles deeper and deeper into the soil, a process called leaching. Leaching can present an especially high risk when the contaminated area is nearby a body of water — and, in the case of the SCC shooting range, the contaminated area is just uphill from the Tuck. 

“There may be a need for more monitoring wells if we see something that’s unusual,” Kritzer said. “The geology in the mountains is a little more complex than it is in the coastal plain, so knowing where the water moves beneath the ground is a little more tricky.”

The DEQ’s plan is to install a cap — made of synthetic liner, clay soil or both — along the bottom of the excavated area and then to engineer the area to create a sediment retention pond that would capture any lead-contaminated runoff coming from the shooting range. Because lead is a heavy metal, Kritzer said, any contamination would settle to the bottom and could then be dredged out periodically. 

The monitoring wells, each about 50 feet deep, would then be installed to get an idea of how far below the ground contamination persists and how — or if — it is interacting with groundwater. That information would then be used to determine whether additional contaminated soil must be excavated. 

The DEQ is making recommendations on the project, but the agency is not funding remediation. That responsibility falls to Jackson County, which owns the property leased for the shooting range and is also the funding source for capital needs at the community college. 

At this point, it’s unknown how much it might cost to implement all of the DEQ’s recommendations, or how long it might take to complete. A civil engineer would need to design the sediment pond and cap. SCC President Don Tomas told commissioners last week that the four wells are estimated to cost about $14,400 to install.

“That’s a good deal,” responded Commissioner Mickey Luker. 

Tomas said that the ongoing monitoring cost would be “pretty insignificant,” likely consisting of an annual round of sampling and testing. The sediment pond would also have to be dredged periodically and the material bleached and disposed of. 

It’s possible that the recommendations could be implemented without the county allocating any additional funding, Tomas added. In July, commissioners approved bids totaling $237,000 for CCI to treat and remove the soil and ECS to oversee the project. However, of those funds only about $105,000 has been paid out thus far. When invoices for this phase of the project are settled, about $100,000 is expected to remain in reserve.

Work to install the monitoring wells would likely begin in January, Tomas told commissioners. According to Kritzer, the DEQ would like to see the wells installed within the first quarter of 2017. 

“This firing range is very useful to the community and to local law enforcement,” Kritzer said, “so the intention is to continue using it but at the same time let’s do what we can to protect public health.”

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