U.S. lakes, Catskill reservoir system, show rising saline levels from wintertime road salt

This story appeared in the Albany Times Union

Lakes in the Northeast and elsewhere in the U.S. are getting saltier, according to a new study by a Hudson Valley based science group. Among those showing rising levels because of salt being applied to roads in the winter are four Catskill reservoirs used by New York City for drinking water.

The reservoirs, which help supply water to 9 million people, were among more than 370 lakes and other bodies of water examined in a study published Monday by the peer-reviewed journal Proceedings of the National Academy of Sciences.

The report found levels creeping up in the city reservoirs in Schoharie County, as well as Cannonsville and Pepacton, Delaware County, and Neversink, Sullivan County. It also found salt levels are rising in Lake Champlain.

That study found that more than four lakes in every 10 — based on long-term records spread across 20 states from New England to Minnesota and the Rocky Mountains — show rising chloride levels during the last decade linked to the wintertime use of road salt.

'There is a big pattern here,” said Katherine Weathers, an ecosystem ecologist at the Cary Institute of Ecosystem Studies in Millbrook, Dutchess County, who co-authored the study. Cary post-doctoral student Hilary Dugan, now a lake and waterbody sciences professor at the University of Wisconsin-Madison, is the study's lead author.

Lakes that are near paved roads, parking lots and other surfaces that routinely receive road salt show levels that are rising slowly, but steadily, said Weathers. Salt from roads washes into drainage systems, which ultimately drain into the nearest large body of water.

Each year, 23 million tons of road salt are applied to roads in the United States. Use has been rising, up from almost nothing during the 1940s.

“The potential for steady and long-term salinization … is high,” according to the study. If current trends continue, many lakes will become too salty to support current levels of aquatic life by 2070, it found.

Adam Bosch, a spokesman for the New York City Department of Environmental Protection, which oversees the reservoir system, said salt levels are “slowly and steadily increasing over time.”

However, he added, levels remain well below drinking water standards, and are expected to remain so for decades to come. That limit is 250 parts per million, and the reservoir system averages 24 ppm, he said.

“This is not a major problem,” Bosch said. For the Catskill reservoirs, the levels are Cannonsville (7.7 ppm), Schoharie (6.5 ppm), Pepacton (4.8 ppm) and Neversink (2.6 ppm).

Salt levels are markedly higher in the original reservoir system in Westchester County, which is more populated and has more paved roads, than in the Catskills.

In the Capital Region, road salt has become a worsening issue in Lake George, where during the last three decades salt levels have tripled. Lake George, at 16 ppm, is about 30 times saltier than an undeveloped Adirondack lake.

The conservation group Fund for Lake George has estimated that each year, 30,000 metric tons of road salt are applied to state and local roads in the Lake George basin — enough to fill 300 rail cars, equivalent to a train 3 miles long.

“Road salt is being called the acid rain of our time with good reason. This study shows the breadth of a problem that only grows worse,” said Eric Siy, executive director of the fund. “Unlike acid rain, however, it can be solved locally, which is exactly what we're doing at Lake George.”

The group is part of a SAVE Lake George Partnership, a coalition of environmental and municipal groups that are seeking ways to reduce salt by such methods as the use of special plows that clean more of the road surface and the timing of applications to make reduced usage still effective.

Rising salt levels can also change wildlife. Research last year from Rensselaer Polytechnic Institute found that rising levels in waters where frogs breed can skew the gender balance of offspring to disproportionately female, 60 percent to 40 percent.

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