Decades of acid rain and the widespread use of road salt have left their signatures on the water quality of Lake George, though new research shows that the lake is slowly recovering from environmental stress.
“But,” conclude the authors of a recently published scientific paper, The Chemical Evolution of Tributaries to Lake George, “the period of recovery will be decades long.”
Lead author of the peer reviewed study is Dr. Jim Sutherland, a retired New York State Environmental Conservation scientist and currently a Scientific Advisor to the Lake George Association and to the Lake George Waterkeeper.
Lake George Waterkeeper Chris Navitsky is among the co-authors of the study, which was published in the academic journal Science of the Total Environment (STOTEN) in January, 2026. The paper’s other two co-authors are Dr. Steve Norton of the University of Maine and Dr. Jack Crosby of the UK Centre for Ecology and Hydrology. The researchers presented their findings at the 2025 Salt Summit in Lake George.
“To our knowledge, this is the first publication world-wide that has evaluated the effect of acid rain and road salt on the balance and movement of contaminants through watershed soils,” said Dr. Sutherland. “We were fortunate to have access to data extending from 1970 to 2024, representing one of the most comprehensive, long-term datasets available for the Lake George watershed.”
The data was collected across decades that happened to coincide, historically, with years when the individual and cumulative impacts of acid rain and road salt could be detected and measured, said Sutherland.
Threats to Water Quality: From Acid Rain to Road Salt and Climate Change
Led by Sutherland, the team analyzed more than 4,300 water samples collected intermittently over a period of 55 years from 18 tributaries coursing through lands that comprise nearly 40% of the Lake George watershed.
As the paper notes, the Lake George watershed has been subjected to any amount of environmental abuse since World War II – from acid rain, road salt, climate change and the disturbance and development of the surrounding landscape, among other things.
To quote from the paper, “While these stresses have been sequential in their arrival, they frequently overlap in time, with the impacts of newer stresses superimposed on the legacy impacts of older stresses.”
Among other things, the researchers found that acid rain – the product of industrial emissions released into the air throughout the Midwestern and Eastern United States – significantly altered the lake’s ecosystem.
“We didn’t see acid deposition impact Lake George as directly as we saw it impact lakes and ponds in much of the Adirondacks, in places where I spent most of my career with the DEC,” said Sutherland. “But it had an impact nonetheless. Acidic deposition was falling on the watershed, across the drainage basin. If we didn’t see it, that’s because its impact was beneath the surface. It was silent.”
As the impacts of acid rain accumulated, the soils were robbed of essential nutrients such as calcium, magnesium and potassium, in some cases, to the detriment of the health of the Forest Preserve, in others, as sulphates, metals and even some otherwise valuable nutrients were exported to tributaries and to the lake itself, to the detriment of water quality.
Sulfur pollution from fossil fuel emissions peaked in the late 1970s. Following the passage of the Clean Air Act of 1970 and Clean Air Act Amendments in 1990, the cuts in emissions mandated by Congress – as measured and monitored by scientists from the Darrin Freshwater Institute, among other organizations – led to a partial recovery from the effects of acidification across regions like the Adirondacks.
Road Salt
On Lake George and across the northeast, acid rain and the heavy use of road salt elided into one another.
“As acid deposition responded to the Clean Air Act and the Clean Air Act amendments, acid rain became less of an issue. Road salt became more of one,” said Sutherland, explaining that the use of road salt slowed the lake’s recovery from acidification and, in some cases, may have reversed gains.
“Road salting further depleted soil calcium, magnesium and potassium, slowing recovery,” the authors state in the January, 2026 paper.
According to the study, sodium chloride accumulates in soils and displaces naturally occurring nutrients, such as calcium, which are released into groundwater and then flushed into streams and the lake.
Researchers observed that concentrations of these nutrients in the lake’s tributaries rose for decades as they were leached from soils.
“After an especially snowy winter, when salt was used more heavily, the streams responded with higher concentrations of calcium,” said Chris Navitsky.
The calcium released into the tributaries and outfalls may contribute to the creation of micro-environments for Zebra mussels and Asian clams, Sutherland and Navitsky said at a March 27 interview at the LGA’s office in Lake George.
From 1980 until 2010, roughly 15,000 tons of salt – or the equivalent of three railroad carloads – were spread across the Lake George basin’s roadways every year, said Navitsky.
Since 2015, the year the Lake George Waterkeeper launched the annual Salt Summits, the governments’ use of road salt has begun to shrink and the contamination of groundwater, tributaries and ultimately of the lake itself has slowed, thanks in part to tactics introduced at the annual Salt Summit – among them: applying the salty, liquid solution known as brine, which acts as an anti-icing agent in advance of a storm; using live edge plows that conform to a road’s erratic surfaces; tracking salt application rates; calibrating salt spreading equipment; monitoring salt use during storms and performing post-storm evaluations.
Concentrations of sodium and chloride in the lake’s tributaries began to decline around 2016.
Climate Change and other Stresses
During the winter of 2016-17, Dr. Sutherland himself noticed that much less road salt was deposited in a brook that flows through Bolton Landing to Lake George. And that was not simply because highway crews were becoming more strategic in their use of salt to keep roads clear of snow and ice.
“There was not much snowpack that winter, and because there wasn’t much snow on the roads to be melted, there was not much road salt in the runoff. Since then, we have not really had a typical winter for the Lake George Basin, with several feet of snow. But that winter was the turning point,” said Sutherland.
Climate change, in other words, was playing a role in shrinking the load of road salt deposited into Lake George’s tributaries and, ultimately, the lake itself.
In the course of compiling his data about the impacts of acid rain and road salt on Lake George’s tributaries, Sutherland was able to document something else: the climate of Lake George is changing.
Since 1970, temperatures in winters and summers have increased “by a significant amount,” said Sutherland. And less snow falls to the ground every winter and more rain falls every summer.
“Overall, there has been a 2.5-degree temperature change within the Lake George Basin during the past 55 years. Summer temperatures have increased by 1.5 degrees, winter temperatures by nearly 3.5 degrees,” said Sutherland.
Precipitation also trends along discernible lines, Sutherland said.
“The annual mean precipitation in this area has increased by six tenths of an inch. Summer mean precipitation has increased by two inches. Winter mean precipitation has decreased by roughly an inch,” he said.
Sutherland and his co-authors say these changes could have significant implications for water quality.
Changing weather patterns, for example, may affect runoff. Heavier rain events and seasonal shifts can flush accumulated pollutants — including sodium and chloride from road salt — into tributaries and the lake.
Temperature also plays a role in how tributary waters enter the lake. Previous research cited in the study found that about 90% of the depth at which incoming streams settle is controlled by temperature, with salinity accounting for the rest.
Warming waters, in other words, could change how pollutants are distributed within the lake, potentially affecting deep-water oxygen levels and nutrient release.
The study suggests Lake George may already be experiencing incomplete seasonal mixing, a condition that can trap low-oxygen water at depth and alter chemical balances.
Monitoring is Key to Protecting Lake George
Climate-driven changes could also interact with other stressors — particularly legacy pollution from road salt and acid rain — in ways that have yet to be fully understood.
Despite these concerns, the researchers said there are reasons for cautious optimism.
“If we continue to use of best management practices, it is likely that we will continue to see reductions in concentrations of contaminants,” said Sutherland.
However, recovery will be decades long, given the residual contaminants in the soils, in the streams and in Lake George itself.
Moreover, the researchers warn that climate change could continue to interrupt or complicate the lake’s recovery. As temperatures continue to rise and precipitation patterns shift, monitoring and measuring the climate’s interactions with legacy pollutants will, the researchers argue, be required if Lake George is to be protected.
