CORINNA — Low concentrations of chlorobenzenes continue to show up in tests of private well water in Corinna, but not at a dangerous level, according to a state Department of Environmental Protection official.
Three years ago, 16 homes and a school in the downtown area became part of a municipal water system because of chlorobenzene contamination in their private wells attributed to the former Eastland Woolen Mill. Since then, ongoing tests by DEP show other wells in the area have traces of the chlorobenzenes.
The DEP samples at-risk homes regularly to assure property owners the contamination is not increasing, said Kathy Niziolek, DEP project manager, this week. Most recently, testing found two homes with traces of the chemical in the fall, when ground water is traditionally low. Last May, when ground water levels were higher, seven “hits” were discovered in the testing.
Niziolek was cautious to point out the levels detected do not pose a danger to local residents.
“We’re continuing to take samples in homes at risk of contamination,” said Niziolek. “Since additional residences have shown some impact, with very low levels, we’re keeping an eye on it.
“The DEP `action level’ is one-half the level that would have a deleterious effect on people,” she continued. “If that level is reached, the department would take action to provide protection from contact with the water or provide a hook-up to the [municipal] water supply.”
Chlorobenzene is a byproduct of woolen manufacturing and was routinely dumped into the Sebasticook River for decades until a sewage treatment plant was constructed in Corinna in the 1970s. Today, the concentration of the chemical in the soil, around the mill site, in the river bed and in contaminated wells continues to hold DEP attention.
The levels of chlorobenzenes in the tests of other homes in the downtown area not originally affected is an indication the ground-water flow is shifting from its previous path, Niziolek said. She said it is possible the lack of draw from the 17 contaminated and abandoned wells has allowed the ground water to shift and be directed at wells still in use.
Heavy draw on a water supply can artificially redirect the water’s natural path. Without the draw of the 17 buildings now on the system, the ground water may be redirecting itself in a more natural flow or be drawn to other wells in the area.
Chlorobenzenes do not have an affinity for water, but readily attach to soils, Niziolek said. The fact that the chemical can be detected in the water is an indication of the concentration in the soils surrounding the contamination.
“Chlorobenzenes are more dense than water,” she said. “They sink.”
Niziolek also explained the chemicals may affect plant and aquatic life, but they do not contribute to phosphorus runoff and the annual algae bloom common in Sebasticook Lake to the south.
“It’s not that type of nutrient,” she said.
Test borings taken last summer in the riverbed in Corinna found the soil contamination as deep as 7 feet in some locations. The depth, the concentration, the movement, and the general unpredictablity of the contamination caused DEP officials, Niziolek included, to suggest last week to town officials they may want to seek an identification for the National Priorities List maintained by the federal Environmental Protection Agency.
The designation would make the community eligible for a Super Fund cleanup of the Eastland site and the areas that are affected. Federal funding for a cleanup or containment can be a larger, more comprehensive project than individual projects under the state’s DEP.
As yet, no action has been taken on the recommendation by town officials.
A major part of any cleanup program should be a bedrock hydrology study, Niziolek said. Such a study could determine how and where the contaminated ground water is flowing, and possibly suggest how high velocity wells could alter the flow or how to correct it to avoid additional contamination.