Road salt could embitter northeast ecosystems

nate steiner via/Flickr
January 6, 2014

Harsh winter weather events bring with them the routines of de-icing sidewalks, walkways and roads. It’s a regular chore and rock salt is a cheap and popular agent. Once winter is over, most of us pack up what’s left of our salt for the season, but that doesn’t mean it’s gone.

Ecologists have been noticing a change in the ground water throughout the northeast. It’s getting salty.

“The problem with salt is that plants don’t take it up, it doesn’t bind to soils and so over time as it makes its way into wetlands, it concentrates.”

Nancy Karraker, an Assistant Professor of wetland ecology at the University of Rhode Island, she says she and other biologists have been documenting an increase in the salinity of ground water.

They believe the main culprit is the salt used on roads.

Some areas in the northeast have been found to have ground water that has 25 percent the salinity of sea water. The most likely places are vernal or seasonal pools, roadside drainage ditches and in some cases, reservoirs.

Karraker says sodium contamination poses health risks to delicate ecosystems.

“In the spring, when the snow is melting, and the salts are being transported from the road into the wetlands, that’s the exact same time when amphibians like wood frogs or spotted salamanders are laying eggs. So their embryos, their eggs are exposed to high levels of salt.”

What sodium-contaminated water doesn’t seem to bother are the eggs and larvae of the Culex mosquito. Also known as the southern house mosquito. The Culex thrives in salty shallow water and can carry several diseases including the West Nile Virus.

Current EPA standards for drinking water allow for 20-milligrams of sodium per liter and so far only a few cases road salt contamination have been documented. However, Kerrack and other ecologists say continued development will increase salt-levels in the ground water of the north-east.