photo by comedy_nose (source: Flickr Creative Commons)

Frogs can’t seem to get a break. Yet another enemy of the vulnerable amphibians – at least in cold countries – is sodium chloride, or NaCl, which is used in many parts of the world to grit icy roads in the winter in order to make them more drivable. The problem is that it’s toxic to aquatic animals and plant life – especially frogs. This becomes an issue as soon as the weather warms up and the snow and ice begin to melt. According to a New York Times piece, sodium chloride runoff is particularly taxing for Chicago’s frogs, fish and aquatic plants:

‘Above-freezing temperatures melt the city’s roadside snowbanks, sending an annual average of 270,000 tons of road salt into the state’s waterways and giving flora and fauna a super-sized serving of NaCl.’

–New York Times

‘It’s not easy being green’, jokes aside, this is no laughing matter (as if you would even laugh at such a weak play on words). The UK and Canada also experience environmental concerns due to road salt runoff, as an article in the Guardian from last winter explains. The most sensitive species are amphibians, but they are not alone from the dangers of chloride-based salts:

‘Road salt can also damage, or even kill, trees and vegetation growing close to the verge, according to reports in Canada. And it can also impact on the health of migratory birds.’

–Guardian

Heating roads, as is done in some parts of Japan, may be one solution, but that is only feasible for urban areas. Sand and grit – or gravel – are also used in an admixture with salt when salt is in short demand, which at least lessens the amount of chloride runoff.

by Graham Land

Additional resources:

The Environment Report – Canada to Declare Road Salt Toxic? (audio)

Frogs – The Global Frog Crisis