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For healthier lakes, rivers, and drinking water, hold the salt
https://cen.acs.org/environment/water/healthier-lakes-rivers-drinking-water/97/i6For healthier lakes, rivers, and drinking water, hold the salt
Road salts, fertilizer, and other pollutants are turning fresh water salty, endangering ecosystems and water supplies
by Deirdre Lockwood, special to C&EN
February 4, 2019 | APPEARED IN VOLUME 97, ISSUE 6
According to an old superstition, it’s bad luck to spill salt, and if you do, you should throw a pinch over your left shoulder to reverse the curse. These days, humans are spilling so much salt into the environment, it’s hard to imagine being able to ward off the bad luck looming on the horizon. We are unwittingly adding chlorides, bicarbonates, and more into groundwater, rivers, and lakes at a pace that scientists worry is threatening wildlife as well as drinking water.
Fresh water of the type that fills streams and lakes typically has about 1% of the salt content of ocean water. In 2005, Sujay Kaushal, a biogeochemist at the University of Maryland, College Park, and his colleagues found that the chloride content of streams in the northeastern US had been rapidly increasing since the 1970s. Some streams had become so salty that their chloride levels reached about 25% of the level in seawater (Proc. Natl. Acad. Sci. U.S.A. 2005, DOI: 10.1073/pnas.0506414102). In some streams supplying drinking water to Baltimore, near Kaushal’s university, levels of chloride had at least doubled over 25 years, according to long-term municipal data.
Since that early study, Kaushal’s team has discovered similar salinization trends in hundreds of streams and rivers across broad regions of North America and Europe, as well as in Russia, China, and Iran. And Hilary Dugan, an aquatic scientist at the University of Wisconsin–Madison, and her colleagues have shown that this is also a widespread phenomenon among North American lakes (Proc. Natl. Acad. Sci. U.S.A. 2017, DOI: 10.1073/pnas.1620211114).
What is behind this surge in saltiness? One of the biggest culprits is road salt, especially in regions that get big snowfalls in winter, like the northeastern and midwestern US. Municipalities in the US have been using road salt as a deicer since the 1940s. But over the years, as more roads have been added and people have become more reliant on clear roadways in winter so that they can travel safely and unencumbered, road salt use has mushroomed. The US now applies 22 million metric tons of it per year, compared with about 4,500 metric tons in the early 1940s, according to reports by the Cary Institute of Ecosystem Studies.
…
Road salts, fertilizer, and other pollutants are turning fresh water salty, endangering ecosystems and water supplies
by Deirdre Lockwood, special to C&EN
February 4, 2019 | APPEARED IN VOLUME 97, ISSUE 6
According to an old superstition, it’s bad luck to spill salt, and if you do, you should throw a pinch over your left shoulder to reverse the curse. These days, humans are spilling so much salt into the environment, it’s hard to imagine being able to ward off the bad luck looming on the horizon. We are unwittingly adding chlorides, bicarbonates, and more into groundwater, rivers, and lakes at a pace that scientists worry is threatening wildlife as well as drinking water.
Fresh water of the type that fills streams and lakes typically has about 1% of the salt content of ocean water. In 2005, Sujay Kaushal, a biogeochemist at the University of Maryland, College Park, and his colleagues found that the chloride content of streams in the northeastern US had been rapidly increasing since the 1970s. Some streams had become so salty that their chloride levels reached about 25% of the level in seawater (Proc. Natl. Acad. Sci. U.S.A. 2005, DOI: 10.1073/pnas.0506414102). In some streams supplying drinking water to Baltimore, near Kaushal’s university, levels of chloride had at least doubled over 25 years, according to long-term municipal data.
Since that early study, Kaushal’s team has discovered similar salinization trends in hundreds of streams and rivers across broad regions of North America and Europe, as well as in Russia, China, and Iran. And Hilary Dugan, an aquatic scientist at the University of Wisconsin–Madison, and her colleagues have shown that this is also a widespread phenomenon among North American lakes (Proc. Natl. Acad. Sci. U.S.A. 2017, DOI: 10.1073/pnas.1620211114).
What is behind this surge in saltiness? One of the biggest culprits is road salt, especially in regions that get big snowfalls in winter, like the northeastern and midwestern US. Municipalities in the US have been using road salt as a deicer since the 1940s. But over the years, as more roads have been added and people have become more reliant on clear roadways in winter so that they can travel safely and unencumbered, road salt use has mushroomed. The US now applies 22 million metric tons of it per year, compared with about 4,500 metric tons in the early 1940s, according to reports by the Cary Institute of Ecosystem Studies.
…
