New wells for Vernay clean up
- Published: July 21, 2011
The two new capture wells that appeared at the Vernay Laboratories site on Dayton Street this summer are adding to the forces aimed at cleaning up the industrial contamination at the site. The capture wells, which are scheduled to begin operation this summer, will increase the extraction of contaminated groundwater on and around the Vernay site. The wells are part of an interim remediation measure Vernay and the U.S. Environmental Protection Agency agreed upon this spring, according to Dave Petrovski, who manages the project for the EPA.
Since signing an Administrative Order on Consent with the EPA in 2002 to contain and reduce the spread of the toxic plume below the ground, the company has installed dozens of testing wells to define the extent of the plume and two capture wells to extract contaminants of concern. While the two initial capture wells are removing some of the pollutants, according to the EPA’s interpretation of the quarterly data from the test wells, some of the wells show contaminant levels in the Cedarville aquifer that remain above the maximum contaminant levels (MCLs) for safe drinking water. The EPA therefore felt the additional capture wells were needed to reduce the contamination more fully and at a faster rate.
“It’s a fairly widespread area that’s above the MCLs, and the idea is to get those concentrations as low as possible as quickly as possible,” Petrovski said in an interview this week.
The data from the wells can be interpreted in many different ways, according to Petrovski. Some wells show contaminant concentrations going down a small amount, while others appear to show contaminant levels stabilizing at above the MCL, he said. One well in particular at the corner of Green Street and Lawson Place shows contaminants that weren’t present before this year, according to the 2011 report from The Payne Firm, Vernay’s consultant firm. And the EPA doesn’t want to take any chances.
“We want unambiguous evidence that concentrations are decreasing,” Petrovski said. “Hopefully these new wells will remove the ambiguity, and the new data will show that the site is heading in the right direction.”
While Payne stated in a corrective measures proposal in 2009 that the two initial wells were adequate to contain and reduce the plume, after conversations with the EPA during which various interpretations of the data were discussed, Vernay agreed to be more prudent. In May the company initiated the installment of the two new wells, Vernay President Ed Urquhart stated in an e-mail this month.
“The first two wells that we drilled have proven to be very effective at controlling the spread of the contamination plume and in fact drawing it back, reducing contamination levels. The addition of two more wells strategically placed should provide even greater control and degradation of the plume. We expect measurable improvements within the next couple of months…The additional wells should expand the capture zone, and even if they are technically not necessary, I felt it makes sense to be on the aggressive side. They can’t hurt.”
The new wells were installed on the southern and eastern boundaries of the property formerly known as Rabbit Run farm, which Vernay purchased last year to give the company more options, Urquhart said in the e-mail. Those wells are intended to draw the contaminant plume away from the Omar Circle area and to prevent further migration of the plume in the eastward direction, he said. According to Payne’s most recent report, the wells extract groundwater, neutralize it with activated carbon and then discharge it to the municipal wastewater system. As of January 2011, the company had treated 69 million gallons of water since 2002.
Urquhart anticipates getting an update to the community on data from the new wells and the status of the plume sometime this fall. If the desired affect is achieved, all four wells are likely to remain part of any final corrective measures Vernay and the EPA settle on, Petrovski said, including soil excavation and remediation. Petrovski could not estimate when the final measures would be established, but said that a period for public comment will precede any final decision.
A group of neighbors who have court-appointed oversight of the Vernay remediation with a consultant firm, EHS Technology Group, supports the decision to add the new extraction wells and to conduct vapor intrusion testing to assess the risk of exposure to hazardous indoor vapors, as Petrovski affirmed the EPA plans to do. But EHS recommends further remediation action. According to a letter to the EPA from the oversight group’s attorney, David Altman, EHS calculates that four piezometers, or smaller observation wells, should be installed near four of the existing test wells in order to fully “determine the radius of influence of the new capture wells.”
The contamination off the Vernay site is currently limited to the Cedarville aquifer, which is far enough below the ground that as long as residents aren’t using well water, they should not be at risk of coming into contact with it, Petrovski said. The contaminants of concern include tetrachloroethene, trichloroethene, cis-1,2-dichloroethene, vinyl chloride and 1,2-dichloropropane. The EPA’s risk contractors are evaluating the potential threats posed by vapors from the volatile organic compounds. Those analyses will also be considered when the final corrective measures are established, he said.