Washington, DC Area Could Soon Need Desalination Plants as Waterways Get Clogged With Salt Runoff

Despite the health dangers of consuming too much sodium, low blood sodium, or hyponatremia, can also cause life-threatening developments in the human body. Fixing blood salinity is a major role of the kidneys, and either too much or too little salt can seriously tax them.

The Chesapeake Bay region has long been plagued by runoff from one or another kind of human activity, including sediment from tobacco farms, nitrogen from poultry farms, and phosphate fertilizers from others, to say nothing of industrial pollution. However, decades after strong environmental regulations helped remove many of the contaminants, a new one is seeping in: salt.

“Salt is probably the most serious problem in world history related to water,” University of Maryland biogeochemist Sujay Kaushal told the Washington Post.

“Eventually, we know, in the human body, that when you harden the arteries, you create hypertension and all these health problems,” Kaushal said. “It’s the same in the environment. You start crossing these thresholds where you see all these environmental impacts.”

Salt interferes with all kinds of biological activities in different creatures, including how they process water, and it is highly corrosive of metals, concrete, and other materials. However, salt is also an effective cleaner, and its ability to lower the freezing temperature of water has made it an invaluable tool for road and sidewalk safety when winter weather hits.

The US uses about 22 million tons of salt on its roads each winter, or about 123 pounds of sodium chloride for every American. In addition to the roughly $5 billion in damage it causes to roads, bridges, and other infrastructure as it washes away, that salt also flows into the soil and drain pipes, which strips off many chemicals, and enters waterways, adding tons of salt where it never existed before, according to the US Environmental Protection Agency (EPA).

Joining the road salt are salts from myriad other products, including detergents and other cleaners and industrial runoff. Typically, many of the tidal Chesapeake Bay waters are brackish, containing smaller amounts of salty seawater diluted by the freshwater streams that drain mountain valleys to the north and west, but the salt runoff is steadily increasing the salinity beyond natural limits.

In many of the waters near Washington, DC, like the Occoquan Reservoir and the Potomac River it flows into, salt levels are nearing those deemed to have effects on human health, and they’ve already affected local wildlife. If the trend isn’t reversed soon, the region is going to need desalination plants like those used in Israel to make Mediterranean seawater drinkable.

There are a variety of alternatives or additives to road salt to lessen its use, but no clear alternatives, short of moving our society away from one centered on car-driven roads or simply accepting that travel won’t be possible with heavy snow on the ground. One expensive, but promising alternative is replacing asphalt roads with solar-powered roadways, which would be able to melt the snow and ice with built-in hot water pipes, but the technology remains prohibitively expensive.

On the upside, maybe with global warming, icy conditions will become less of a worry in many places in the coming decades.