We have a salt problem and don’t mention the diet. Although salt is effective in de-icing highways in winter, new studies show that widespread use of salt is also damaging freshwater ecosystems.
In addition, salinity, which is considered safe by US, Canadian, and European regulators, does not do enough to protect marine life. The biodiversity and normal functioning of these ecosystems is currently under serious threat.
Researchers are pointing to road salt and the use of salt in agriculture and mining as the reason for the rising concentrations in water. They are also calling for stricter government control over the use of salt.
Jonathan Schrin, an ecologist at the University of California, San Diego, said: “This study suggests that the levels considered safe need to be revised downwards.”
Researchers have begun experiments at 16 sites in the United States, Canada, Sweden, and Spain, noting the effects of increased levels of sodium chloride (one of the most common types of salt) in water taken from lakes. did.
Even the thresholds considered safe (230 milligrams of chloride per liter in the United States and 120 milligrams of chloride per liter in Canada) had a significant loss of zooplankton and an increase in algae. The European threshold was usually higher.
Zooplankton is an important food source for young fish, and its disappearance has a significant knock-on effect. At 73% of the sites, more than half of the zooplankton population was killed at approved salinity levels in Canada and the United States.
When the zooplankton disappears, the algae expand.
“Increased algae in the water can reduce the transparency of the water and can affect the organisms that live at the bottom of the lake,” said Shelley Arnott, an ecologist at Queen’s University in Canada. I am.
“The loss of zooplankton, which leads to more algae, can change the lake’s ecosystem in ways that can change the services the lake provides: recreational opportunities, drinking water quality, and fishing. “
Researchers conducted the same experiments at 16 separate sites and obtained similar results, indicating that the problem is the same despite local differences in geology, land use, and hydrochemistry. I am. The salinity of freshwater systems can last for decades, so it is important not to increase salinity in the first place.
Researchers say that the benefits of using salt, especially to prevent road accidents, need to be carefully balanced with the impacts on ecosystems, especially when conditions change as a result of climate change. ..
“The results of this study show that levels of saltiness that damage ecosystems are lower than previously thought, and that fish, algae, and other organisms can be affected at levels commonly found in the field. Shows, “says Shurin.
“Transportation, which determines the amount and timing of salt application to roads to melt ice, follows these guidelines.”
If you want to protect freshwater ecosystems for the future, you need to set stricter limits on salt pollution.
The study is published at PNAS..
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