https://phys.org/news/2018-10-plant-based-road-salt-good-highways.html

In addition to potential vehicle and infrastructure damage, salt-based deicers can be dangerous to freshwater animals. Excess salt that flows from the roadways into freshwater sources disturbs internal fluid balance in aquatic life that is essential for survival. However, due to the high cost of beet juice deicer products, municipalities in Canada often treat winter roads with a mixture of the plant-based deicer and less expensive road salt.

The research team examined the physiological responses of immature mayflies (mayfly nymphs) when the freshwater insects were exposed to beet juice deicer. "Mayflies can act as water pollution indicators as they are particularly sensitive to runoff contaminants such as road salts and metals," the researchers wrote. They found that compared to a control group, the insects exposed to beet juice deicer retained significantly more fluid while blood salt levels were elevated, which can compromise organ function. . The mayflies' gills also were excreting salt as a result of exposure to beet juice deicing agent, which is the opposite of their normal function. This is not unusual, explained Cuciureanu, because beet juice is rich in potassium, a mineral that mayflies are particularly sensitive to. The researchers were surprised to find, however, that the potassium concentration of the deicer was lower than they had anticipated and should not have caused as much physiological stress as it did.