The city of La Crosse will need to come up with a long-term plan for a well near the airport that has been shut down for three years due to contaminants, according to a letter sent this month by the Wisconsin Department of Natural Resources.
The DNR determined the site of municipal wells 23 and 24 poses a potential threat to public health, safety, welfare or the environment after three years of testing by the La Crosse utilities department, which hasn’t been using the well in order to keep the contaminants isolated.
“The WDNR also believes that a response action in the form of additional investigation and possible remedial action is needed due to the known impacts above the health advisory level of municipal well 23, and the potential for impacts to municipal well 24,” said Dave Rozeboom of the DNR in a letter to the city dated May 10.
The letter was no surprise to utilities manager Bernard Lenz, who said the city has been running tests on the wells, looking for contaminants called polyfluoroalkyl substances, known as PFAS, for years.
“This is an example of why we do the amount of testing we do and why we catch things. The amount of testing we do is above and beyond anything you’d have in a private well. It makes the public water supply far safer than the private wells,” Lenz said.
The city found PFAS in the well in 2014, but at the time the amount wasn’t deemed dangerous.
“It was a very, very small concentration. We’re talking two drops in an Olympic-sized swimming pool,” Lenz said.
La Crosse shut down Well 23 entirely and has used Well 24 sparingly since May 2016, when the Environmental Protection Agency lowered the safe threshold for concentration to 70 parts per trillion, putting the concentration found at Well 23 near the La Crosse Regional Airport five years ago above the advisory level. Well 23 came back in 2014 with 140 parts per trillion of PFAS, which was under the previous advisory level of 200 parts per trillion set in 2009.
None was found in nearby Well 24; however, the city has stopped using it, figuring it was better to err on the side of caution.
“These wells are offline. We’re not using them to add water to the public water supply, and until this investigation is complete, Well 23 will not be added to system,” Lenz said.
PFAS are fairly common, said Lenz, because they were used in fireproofing and were unregulated for decades.
“They’re actually in a lot of different places in the environment, and what they’re finding out now is these things are very hardy — they don’t break down easily. They stick around in the environment for a very long time,” Lenz said.
City officials suspect the contaminants near the airport are left over from La Crosse Fire Department training exercises in the 1970s and ’80s. Firefighters collected chemicals from local industries and ignited them, using a fire-fighting foam to extinguish the fires to make sure they would be able to respond to a potential industrial fire.
However, that foam included PFAS, which move very easily through water.
“(The DNR has) got enough evidence to show that water with PFAs is moving toward those wells and it could be a problem, so therefore they want us to do a full investigation of where the source is, how fast or how much is moving toward the wells, how likely it is to impact the wells and then come up with a plan of what we want to do to protect the wells and protect human health,” Lenz said.
While the amount of PFAS is very small, the city and the DNR wants to make sure it doesn’t become a problem. PFAS have been linked to low birth rates in infants, reduced fertility, as well as cholesterol, thyroid and liver problems. The EPA’s advisory levels are based on how it would affect the most sensitive population, including children and people who are pregnant.
“We want to take every precaution and make sure we’re extra safe when it comes to our drinking water,” La Crosse Mayor Tim Kabat said.
The Board of Public Works on Monday will take the first steps to following the DNRs remediation and redevelopment program.
“With the DNR reopening their letter and sending us some action steps and some deadlines, we’re going to respond and meet those deadlines and provide a workable plan,” Kabat said.
The city has 30 days to hire an environmental consultant and 60 days to prepare a plan.
“It could be a similar remediation as previously, it could be a much more intense remediation, it could be an abandonment of the wells. We really don’t know until we do a study,” Lenz said.
If it is forced to abandon the well, Lenz said, the city will need to look at drilling more wells.
“You don’t want to have just enough wells to get by, because if anything were to happen, then you’d have a significant problem,” Lenz said.
The current shutdown of wells 23 and 24 has made that back-up capacity pretty thin.
“If this is a long-term solution, to abandon these wells, we would have to drill new wells for backup capacity,” Lenz said.