Mirror Lake is a popular recreational lake located in the Village of Lake Placid.  It is the most developed lake within the Adirondack Park, which is a publicly protected area that is actually larger than Yellowstone, Yosemite, Glacier, and Grand Canyon National Parks combined.

New research has revealed that road salt runoff into Mirror Lake is

preventing natural water turnover which poses a risk to the balance of its

ecology.  The study, which was published

in Lake and Reservoir Management, found that road salt runoff is

preventing spring mixing of the water column.   

This creates more anoxic water conditions, meaning there is less oxygen

in the water, and limits the ability of the habitat to support the native lake

trout. 

Mirror Lake is the first lake in the Adirondack Park to show an

interruption in lake turnover due to road salt. 

Many lakes in northern climes experience so-called “dimictic turnover”,

which is a natural process where wind and less stratified water conditions of

spring and fall allow mixing of the water column that redistribute oxygen and

nutrients throughout the lake.  High

levels of surface-water chloride introduced into the lake from road salt runoff

inhibit the mixing of the water column.

The lack of mixing and oxygenation is bad news for fish species such

as lake trout, which require cold, oxygenated water to survive.  It may also put the lake at a greater risk of

algal blooms.

Mirror Lake is small, surrounded by concentrated development, and

receives the direct discharge of stormwater. 

So, it is particularly vulnerable to road salt contamination.  Other lakes elsewhere in New York may

experience similar conditions.  The

researchers are confident that natural turnover conditions could be restored to

the lake if road salt application in the watershed is reduced.

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Road salt pollutes lake in one of the largest US protected areas, new study shows

Photo, posted January 5, 2018, courtesy of MTA of the State of NY via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.