A contamination running off a former burial plot for a Dartmouth research facility's hazardous waste has reached a local stream.
In late August, for the first time a nearby stream tested positive for the chemical 1,4-dioxane. It was detected at .52 parts per billion levels.
State drinking levels acceptable for the chemical are 3 parts per billion. However, the New Hampshire Department of Environmental Services does not have acceptable standards for surface water contamination.
The plume has already affected at least one family's drinking water.
Michael Cimis, the senior associate director of environmental health and safety at Dartmouth, says while it is alarming that the plume is in the surface water, it is not unexpected.
“I think our experts are telling us that it's not uncommon to have fluctuations in groundwater levels and that can affect the concentration of 1,4-dioxane,” he said. “The drought we're having may contribute to that. In general, when there's less groundwater or rain you would assume to see higher concentration.”
Dartmouth is planning a pump and treatment system to clean up the water contamination.
“The pump and treatment system is designed to capture and contain groundwater in a given area,” Cimis explained. “The effort here is to put wells in a position such that we capture all the ground water in that area. We draw it up out of the ground with pumps, we treat it through a filtering system to remove any 1,4-dioxane and then that material gets pumped back to the top of the site and put back in as clean water to help flush any remaining contamination out.”
Local residents have been dissatisfied with this remediation plan. They asked for full excavation of the site in petitions to the college and the state.
“The important issue right now is to get ground water control in place and we are really working hard to get that done. That will allow us the flexibility to do other things like excavate,” Cimis said. “The groundwater control treatment system includes monitoring, and you can check the performance of that. So Dartmouth would consider excavation if that's needed. But the state and our experts are really adamant that they want the controls in place first.”
Cimis and others fear further excavation could exacerbate the contamination runoff. They speculate the 2011 excavation of the site is what triggered the plume's original movement.
Meanwhile, residents of the Hanover neighborhood are concerned over the movement of the plume into streams.
Marjorie Rogalski lives in the neighborhood.
“My house is located between a stream both on the north side and the south side. The stream in question actually feeds into the foot of my driveway. So it's definitely a concern,” she told VPR.
“The good news is that we're all paying attention now. And hopefully the state and the college will ensure that any levels of increase will be dealt with appropriately,” she said regarding a letter she received from Dartmouth College notifying her and others of the chemical found in the stream.
She is pleased that Dartmouth has become more communicative with neighbors about the plume in the past month.
Jim Wieck is a hydrogeologist and the senior project manager overseeing the Rennie Farm site remediation for Dartmouth College.
A plan for the pump and treatment system was sent to the New Hampshire Department of Environmental Services for review Friday morning.
Wieck says the cleanup process can be frustratingly slow, but it's necessary.
“It's a complicated process and it's important to take it — I don't want to say slowly — but it's important to do a very deliberate job of investigating where the contamination is and where it's moving to and how it gets there so you can design a remediation that's going to be successful,” he said.
Wieck speculates the state will take a couple weeks to review the plan. If all goes well, the new treatment system will be likely be in place by the end of the fall.
The State of New Hampshire will be holding a meeting in mid-September to discuss the cleanup, at the request of Hanover residents.