The city of Dayton stopped pumping water at a Huffman Dam well field in April after a Wright-Patterson Air Force Base monitoring well near the dam showed tainted groundwater above a federal environmental threshold for contaminants found in firefighting foam, officials say.
The Dayton production well field will remain closed until the city and the Ohio Environmental Protection Agency “are comfortable that operation of these wells will not cause the migration” of groundwater contaminants from the base into the city’s well field, according to Michelle D. Simmons, a city water department environmental manager.
Dayton has relied on other well fields to serve 400,000 customers since the shutdown, the second since a three-month closure at the Huffman Dam well field last summer.
However, city and base environmental officials say drinking water in both the city of Dayton and at Wright-Patterson is safe to consume. The threshold exposure applies to drinking water and not groundwater wells, base officials also stressed.
The latest results indicated a monitoring well on the boundary line of Wright-Patterson about a half mile from the dam well field showed a contamination level of 75 parts per trillion, officials said. The U.S. Environmental Protection Agency has a threshold health advisory level of 70 parts per trillion for drinking water from contaminants found in Aqueous Film Forming Foam, a fire suppressant.
One monitoring well more than a mile northeast at a base firefighting site near the Mad River showed 2,700 parts per trillion, Wright-Patterson environmental officials said.
Base will reopen closed wells
Wright-Patterson tentatively expects to reopen two closed contaminated drinking water wells next week in Area A when a new $2.7 million water treatment facility starts operations. Contaminated water will be sent through large tanks with charcoal filters to remove polyfluoroalkyl substances, officials say.
“The drinking water is safe and we are going to continue to work with the regulators, the Ohio EPA, and with the city of Dayton to ensure any concerns or issues are addressed immediately,” Wright-Patterson spokeswoman Marie Vanover said.
The two Wright-Patt wells in Area A were closed a year ago when the EPA lowered the threshold for lifetime exposure to perfluorooctanoic acid, or PFOA, and perfluorooctanesulfonic acid, or PFOS.
The man-made substances were byproducts of Aqueous Film Forming Foam, a firefighting retardant linked to groundwater contamination and potentially adverse health effects on humans, such as development effects on fetuses during pregnancy and breast-fed infants, among other potential health issues, according to the U.S. EPA and researchers.
The U.S. Army Corps of Engineers, meanwhile, will launch a $234,000 study to determine if a new drinking water well should be dug on base or if it should connect with a supply off the sprawling installation, among options to explore, officials have said. An initial report is expected this summer.
The Ohio EPA has cited concerns a contaminated groundwater plume could potentially reach other drinking wells on base and the seven city of Dayton production wells at Huffman Dam.
The two contaminated wells in Area A at Wright-Patterson posed “a continued threat to public health from the potential plume emanation to the city of Dayton well field,” the state agency reported last summer.
The city pulled the Huffman Dam production wells offline last month because of the most recent Ohio EPA recommendations, according Simmons.
“Since Dayton’s Huffman Dam wellfield is downgradient of (Wright-Patterson), we asked Dayton if they could temporarily stop using the Huffman Dam wells,” Ohio EPA spokesman James Lee said in an email Friday. “This would give (Wright-Patterson) additional time to determine the extent of the plume and to conduct sampling of sentinel wells between Dayton’s wellfield and WPAFB.”
The shutdown of water production wells at Huffman Dam last month marks the second time the city has acted to stop production because of the potential threat of contamination. The pumps were closed between June and August last year.
Since then, water had been cycled through one pump each day at Huffman Dam and sent to a treatment facility to keep the pumps in operation, Simmons said. The water will continue to be sent through air strippers on site to reduce groundwater contaminants, but it will not be sent to a treatment plant, Simmons said.
Additional tests for contamination
None of the city’s monitoring wells at the Huffman Dam well field sampled in December showed contamination levels above the EPA threshold nor has it been detected in the water distribution system, according to Simmons. The wells will be tested again in June, she said.
Wright-Patterson’s latest tests of base monitoring wells were in January, and results were received in recent days. Nine other wells in the vicinity of the boundary well near the Huffman Dam showed levels between 0.3 to 49 parts per trillion, or below the EPA threshold, base officials said.
The base has 79 groundwater monitoring wells in Area A and four planned in Area B, according to Treva Bashore, Wright-Patterson environmental restoration program manager. In the future, the base will sample a well off-site on Miami Conservancy District property near the dam, she said.
Another round of well testing was set this week to verify earlier findings with results due this summer.
Last year, the military installation imposed a months-long drinking water advisory for lactating and pregnant women, and infants and distributed bottled water after the EPA set a new lifetime exposure level. The health advisory was lifted last August.
For years, Wright-Patterson firefighters sprayed a military version of aqueous film forming foam. However, the base has replaced the old foam with a new one the Air Force has described as a more environmentally friendly alternative, Vanover said.
Cleaning up contamination at Wright-Patterson will cost millions of dollars beyond what has been spent at a location in years past the EPA declared a Super Fund site.
In addition to the new $2.7 million water treatment facility, the base has spent about $1.5 million on groundwater testing-related costs, according to Bashore.
A future environmental study will investigate soil, surface water and groundwater contamination and the direction of the contamination plume, officials said.
The study will determine the extent of groundwater contamination “and where it’s going and the impacts,” said Raymond F. Baker, 88th Civil Engineer Group branch chief.
The Air Force will determine which bases have the highest priority for clean-up funding, said George R. Walters, 88th Air Force Civil Engineer Center restoration branch chief at Wright-Patterson.
“We’re going to get all the site investigations throughout the Air Force and whichever ones are deemed to be the highest priority will be contracted first,” he said.
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