Silfa Zoidberg, Twitter asked:
What happens to all the salt put on roads in cold weather?
Chris - Well the answer for that is actually when the ice melts, the salt gets washed to the margin of the road, lots of it ends up in storm drains, so that ends up ultimately going to the sea, so that doesn't really matter. But on country lanes and things, and in residential areas, lots of that salt actually gets washed to the side of the road and then ends up in your garden. And there is a problem with salt contamination of soil because the salt make the soil become very, very saline over time, especially on busy roads that get very large amount of salt dumped on them, and this can actually have a problem for the wildlife, chiefly plants and things like that.