A final decision by the U.S. Environmental Protection Agency on whether to alter the cleanup plan will come by November. The original method required by the EPA and the state was to pump the groundwater up into an above-ground treatment system and then return the water to the ground.
A public hearing has been scheduled for July 16 in Aberdeen, along with a 60-day public comment period.
According to data presented to the Aberdeen Community Liaison Panel, the pesticides appear to be breaking down naturally, possibly eliminating the need for the more expensive treatment method. The panel meets periodically to review the progress of the cleanup.
The panel includes local residents, county and Aberdeen officials, state and EPA representatives, representatives of several chemical companies and their consultants. Chemical companies identified by the EPA as being responsible for the dumps are paying for the cleanup.
EPA regulators appear to be leaning toward allowing nature to take its course in cleaning up the contamination.
Liaison Panel Meets
The Community Liaison Panel met Thursday to go over reports from the consultants, which included more updated data on the levels of pesticides in the groundwater.
That will help the EPA determine whether the cleanup method should be changed, said Jon Bornholm with EPA regional office in Atlanta.
A number of monitoring wells have been installed around the old dumpsites. The pesticide levels in the groundwater must be lowered to standards set by the EPA.
Bornholm said the EPA will continue to monitor the groundwater on an annual basis at least until completion of a five-year review, to make sure pesticide levels continue to decline.
The levels of pesticides in the groundwater dropped significantly after hundreds of tons of contaminated soil and debris were removed from the dump sites several years ago. The soil was treated to remove the pesticides and returned to the sites.
As an experiment, poplar hybrid trees were planted at one of the dump sites near Aberdeen Lake.
It was suspected that the root systems would aid in the natural breakdown of the contamination. Another experiment of injecting a milklike substance in the ground to eat up the pesticides has been less successful, according to the consultants.
“Natural attenuation is considered to be the best solution, providing the best rate with the least risk,” said Billy Hall, a consultant with New Fields.
The concentrations of pesticides in the water have begun to level out toward a common threshold of about 1.5 parts per billion, he said. Concentrations in some of the “hot spots” have been cut in half, mainly due to the trees and the natural degradation, he reported to the group in April.
“We want to finish this,” Hall said. “We’re sick to death of it. If there were technology out there to zap it, get rid of it, we’d use it. If we’re going to spend a lot of money, we want to accomplish something. We don’t have an aversion to application of technology if it will do the job.”
But there appears to be no existing technology that will get rid of the remaining low levels any more effectively than waiting several decades for them to breakdown naturally, he said.
Hall said at the April meeting that the rate of improvement in the groundwater since the soil removal and from other actions has been faster than what was predicted using the pump and treat method.
But the amount of improvement has slowed and will be very slow from now on, he warned.
Harry Huberth, president of MooreForce, a local environmental watchdog group, questioned Bornholm about follow-up monitoring by EPA if final approval is given to leaving the site alone to the work of nature.
Bornholm said there will be a five-year review to ensure that pesticide levels are continuing to drop and that the contamination is not spreading. Monitoring wells will be sampled and tested annually.
He said such actions would be tied to companion N.C. Department of Environment and Natural Resources documents, where monitoring schedules could be found.
“The EPA will come up with the final goals for numbers in the groundwater, and the ROD (Record of decision by the EPA) will specify how clean is clean,” Bornholm told The Pilot. That information will not be ready in time for the July 16 hearing, he said. “We agree with changing the method, but we are still sticking to the old cleanup numbers.”
Those numbers were originally set in 1993-94, based on using the pump-and-treat method.
The Aberdeen Pesticide Dumpsites will also continue to remain on the National Priorities List as long as there is any contamination in the groundwater, he said.
‘Key Is Monitoring’
A fact sheet and written information about the proposed change in method will be published in The Pilot and will be handed out to citizens attending the public hearing on July 16, which is expected to be in Aberdeen at a location to be announced later. The hearing will tentatively be 7 p.m.
“The key word is monitoring,” Huberth said. “The big thing is how much sampling, how frequently. It may be expensive but the only assurance we have now is monitoring. That is the crux of it. We would expect to see a pretty extensive monitoring plan spelled out.”
The lake could become contaminated if a plume of groundwater migrates into it, or if a separate plume goes down below the dam and contaminates the creek that flows from the lake under the dam.
So far, no contamination has reached the lake.
Bornholm said the water below the creek could be included in the monitoring plan. Fish will also be sampled.
Hall commented that monitoring the situation and allowing for the natural breakdown of the pesticides, though less expensive than the pump-and-treat method, costs about $200,000 to sample and test water.
