East Lyme ― The Commission on the Conservation of Natural Resources and the Public Works Department wants the town to take a more careful approach to road salt application.

This comes as Penny Howell-Heller, a retired marine biologist with the state Department of Energy and Environmental Protection, analyzed 17 years of sodium concentration data provided by the town.

She found that five of the seven wells she analyzed revealed an increasing trend in sodium levels from 2005 to 2022. Those five wells remain over the threshold set by the state in which the town must notify all residents in case they are on a low-sodium diet.

Public Works Director Joe Bragaw said his focus is on training staff members from the Public Works, Water and Sewer, and Parks and Recreation departments along with the school district – so they are “all on the same page that it doesn't help to oversalt.”

The state Department of Public Health requires public water suppliers to notify their customers when sodium levels exceed 28 milligrams per liter of water, according to agency guidance. That’s so people on low-sodium diets – often for reasons like heart, kidney or blood pressure conditions – can better monitor their intake.

Howell-Heller said some road salt ends up traveling through pipes into nearby streams, while some makes its way from the road into shallow groundwater.

The town’s public water system draws from wells in four aquifers. It serves about 6,000 customers.

Average sodium levels across the well system started exceeding 30 parts per million about five years ago, Howell-Heller’s analysis showed. But some specific wells revealed earlier and steeper spikes, like the well near Dodge Pond in Niantic first nearing 40 milligrams per liter in 2013 and hitting 42.8 in 2018. The wells near busy Route 161 showed the greatest increase over time at about 1.5 milligrams per liter each year.

The two wells near Route 161 are within 1,000 feet of each other behind East Lyme Middle School, within the aquifer protection zone encompassing much of the main route. The area includes Costco and hundreds of nearby apartments and condos built over the latter half of the previous decade. One well there has shown a sodium level exceeding 40 milligrams per liter.

Howell-Heller said she conducted her analysis using sodium data for each well because the information shared with customers by the Water and Sewer Department had been combining data from all the wells instead of reporting sodium levels individually.

“I think there’s an opportunity that they missed to educate the public by telling them which wells are really a problem, instead of just giving them an average,” she said.

She shared her findings late last year in a memo to officials involved with road maintenance for the town and school system.

Despite existing standards, the state public health agency in published guidance described the 28 milligrams per liter reporting threshold as “dated.” The DPH suggested 100 milligrams per liter is the point at which those on a low-sodium diet should start having discussions with their doctors about salt levels in drinking water.

Howell-Heller emphasized the local trends “are going nowhere but up” even though the numbers don’t represent an immediate threat.

“Our drinking water is very important,” she said. “This is an issue that should be dealt with when it’s not a crisis.”

Michael Dietz, the director of the Connecticut Institute of Water Resources and an extension educator with the University of Connecticut, agreed.

“Overall, I’m not concerned about that concentration as an impact on health,” he said. “What is concerning is the upward trend that’s happening there. So that’s just something that I would be paying attention to if it were my drinking water.”

Dietz said examining chloride levels as well as sodium would give a fuller picture of the salt situation in the water. DPH regulations specify the maximum permissible level of chloride in drinking water is 250 milligrams per liter. He said upward trends in sodium levels tell him chloride should be looked at as well.

Elevated levels of chloride and sodium can make water more corrosive and affect plumbing. They can also accelerate the movement of potentially dangerous heavy metals like lead, cadmium, chromium, and iron in stormwater runoff.

Howell-Heller said she has not seen chloride data for the wells.

Bragaw, who serves as vice president of the University of Connecticut Training and Technical Assistance Center advisory board, said the group is now using its Connecticut Green Sno Pro program to educate private contractors about road salt like it has done for government employees.

A bill was filed as part of this year’s legislative session to encourage training, certification and protection from liability for roadside applicators who are certified through the same program.

In New Hampshire, commercial salt applicators and the property owners or managers who hire them are granted liability protection against damages once they’re certified through the state’s Green SnowPro program.

e.regan@theday.com