Study: Road salt pervades Adirondack groundwater

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SARANAC LAKE — A study of 358 private wells scattered across the Adirondacks found that salt used to de-ice wintertime roads is contaminating groundwater and seeping into private wells.

Daniel Kelting, executive director of the Adirondack Watershed Institute and a professor at Paul Smith’s College, presented the findings of the study to the public at the Saranac Lake Free Library Wednesday night. Officials from several state agencies attended, including the departments of Transportation, Health and Environmental Conservation.

The study, funded by Adk­Action and the Fund for Lake George, found the heavy use of salt on state highways is responsible for most well contamination. While state highways are only one-quarter of the roads in the Adirondack Park, they contribute 55 percent of the road salt. Town and county roads that are maintained by local highway departments also apply salt to roads, but they don’t use it in the same way. Some local roads are not salted at all, while others are salted on an as-needed basis. State highway crews, however, follow strict rules on when to apply salt and how much.

“State roads are all 55 mph [outside communities], and they have to be maintained to the highest level of service,” said Kelting. “They have to be drivable within a certain time frame after an event. Local roads have a variety of levels of salting.

“It makes it simple — to reduce salinization, we need to focus on state roads.”

The study included 132 wells with no road runoff, 114 with state road runoff and 112 with local road runoff. Study participation was voluntary. Homeowners who volunteered received a sampling kit with instructions and mailed their samples to Kelting, who collected and analyzed the data.

“We found regional salinization of surface and groundwater,” said Kelting. “We use too much salt.”

In one year, 192,700 tons of road salt are applied to Adirondack roads. Town and county roads receive 10 tons per lane mile per year; state roads get 37 tons per lane mile per year. (A lane mile is one side of the road, thus one mile of a two-lane road equals 2 lane miles.)

The use of road salt began around 1980, said Kelting. Since that time, 6,937,200 tons of salt have been applied to the roads.

“Roughly one-third of our lakes have road salt in them,” he said. “Fifty-two percent of our streams have salinization.”

Thanks to the coarseness of local soil, water flows easily from the surface into groundwater supplies and wells, Kelting said.

“Salinization has effects on ecosystems, human health and property values,” he said. “Your property values could be affected if your water’s polluted.”

Many of the wells tested were found to be exceeding Health Department guidelines of less than 20 parts per million of sodium. Lloyd Wilson, head of the DOH drinking water program, pointed out those guidelines don’t mean the water is unsafe for everyone. “Those are action levels for those on a sodium-restricted diet.”

Kelting said the natural salinity of water in the Adirondacks, found in wells unaffected by road salt, is less than 0.5 ppm.

Road salt, commonly marketed as halite, is a combination of two elements: sodium (Na) and chloride (Cl). Kelting explained that the two elements form a weak ionic bond, which means they break up and combine with other elements easily. Wells were tested for both sodium and chloride.

“There are other chloride de-icers, which are effective but more expensive,” Kelting said. “Only halite is naturally occurring. The others have to be manufactured.

Pilot program

AdkAction and the state DOT have come up with a pilot program to reduce the use of road salt on state highways. Areas around Mirror Lake, Wilmington and Lake George have been chosen to test methods to keep roads clear while reducing salt usage.

Randy Preston, supervisor of the town of Wilmington and chair of the Essex County Board of Supervisors, was also present at Wednesday’s forum.

“We did some testing, and it was very concerning,” he said of Wilmington. Preston said he initially thought his town would have to fight the DOT to get it to change the road salt usage, but “DOT worked with us. We’re working together to come up with solutions everybody is comfortable with, balancing public safety and the environment.”

Brittany Christenson, director of AdkAction, said the pilot programs will use a whole slate of best-management practices to see what works, including using double blades on plows and using brine instead of dry salt.

“We’re hoping to learn something we can take statewide,” she said.

Highway crews will use double blades and live-edge plow blades to remove more snow and ice from the roads; use treated salt, which is more effective at colder temperatures; use Automatic Vehicle Location technology, which will help equipment operators know how much salt they’re using; evaluate cutting back some of the tree canopy to reduce shade on the roads; and try reduced seasonal speed limits.

Meanwhile, Preston said public workers will continue to test the water to see if the salt load is being reduced.

Preston and Kelting noted that using more sand isn’t the solution. Kelting said that before salt came into use, people had concerns about using sand.

“Sand is not inert,” he said.

“If the sand washes into the streams, it fills up the trout-spawning areas,” said Preston. “The sand has to get picked up.”

Preston said his town’s highway workers have just finished removing sand from state and local roads.

“Is it less harmful than salt? In my opinion, yes, but it needs to be picked up,” he said.

During the forum’s question-and-answer period, a woman from the audience asked, “What do we do now? What should people whose wells are non-potable do?”

The DOH’s Wilson responded, “Private wells are the responsibility of the homeowner.”

By the numbers:

6,937,200 tons of road salt applied to roads in the Adirondacks since 1980

192,700 tons applied in one year

55 percent of that comes from the state, even though only about 25 percent of the roads are state highways

10 tons of road salt per lane mile per year applied to town and county roads

37 tons of road salt per lane mile per year applied to state roads

(Source: Adirondack Watershed Institute)

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