Everything we take for granted about the world around us boils down to a few essential minerals.

By Bill Lawyer

Everything we take for granted about the world around us boils down to a few essential minerals. The trees, shrubs, grasses, animals – including humans — have evolved around the presence or absence them.  

One mineral in particular stands out – salt.

Historical records show that dry salt has been mined, and liquid salt has been processed going back 7,000 years. While on a trip to the Jura Mountains of France some years ago, I visited Salins les Bains, which had an active salt mine up until the early 20th century.   

Now a museum, a guide explained that the land around Salins les Bains was once covered with an ocean, but after the ocean receded, the salt water was enclosed on a lower level and now is surrounded by mountains. It had been operating even before Julius Caesar “came, saw, and conquered, too.”  

The salt harvested from Salins les Bains was very important in cooking, preserving foods, taking therapeutic baths, and playing a critical role in cheese production. Hunters, recognizing that deer and other animals love salt, have used salt licks that attract them, thus becoming easy targets.  

As much as we might appreciate the many uses of salt, this time of the year, when we in the northeastern United States are often assaulted by freezing rain that makes things treacherous, we realize how much we’ve become dependent upon salt for one primary purpose – melting snow and ice on highways.

Looking at road salt in the greater historical perspective, the use of salt for highways, sidewalks, and parking lots is a relatively new phenomenon.

 
Before the mid-20th century, salt was rarely used on roads. There was no high-speed interstate highway system. Before the 1940s, according to the Transportation Research Board of the National Academies, “highway departments relied mostly on plowing and abrasives (e.g., sand and cinders) to keep roadways open after winter storms.” Salt was used primarily as an additive to prevent freezing of sand piles.

Transporting salt was and is expensive, and most motorists used chains or snow tires. Or, they just stayed home.  

While the use of salt varies from year to year, and region-to-region, about 17 million tons are used annually in the United States, according to the Department of Transportation.  

Rye’s Disbrow Park dome holds 1,200 tons of salt. Over the 2013-14 snow season, the City used 3,000 tons of salt.   

Rye has nearly 152 lane miles of roadway that need to be cleared, along with municipal and Metro-North parking lots.This includes a few roads in the Greenhaven section of Mamaroneck. They even provide assistance to the School District’s parking lots.  “Clearing” can mean spreading salt and calcium chloride, or plowing.  

From a natural history perspective, what effect does the use of all this salt have on Rye’s environment? Well, it’s not good. As is the case with humans, all organisms need some salt, but too much can be just as dangerous as too little. Joseph Stromborg, writing in Smithsonian Magazine, cites studies showing the impact of salt runoff on the populations of crustaceans and amphibians. Elevated salt concentrations can reduce water circulation in lakes and ponds (because salt affects water’s density), preventing oxygen from reaching bottom layers of water. It can also interfere with a body of water’s natural chemistry, reducing the overall nutrient load. On a smaller scale, highly concentrated road salt can dehydrate and kill trees and plants growing next to roadways, creating desert conditions because the plants have so much more difficulty absorbing water.

Windblown salt water from Superstorm Sandy caused considerable damage to Rye’s pine trees.

In some cases, Stromborg noted, “dried salt crystals can attract deer…to busy roads, increasing their chance of becoming roadkill.”

So the take-away about salt, the environment, and our transportation safety is that we need to minimize the use of salt, and encourage people to modify their transportation plans during high-risk weather conditions.

As with most things in life on earth – it’s a matter of balance.