(A little surprised no one has posted this yet... maybe it is here somewhere and I just missed it.)
Perhaps this isn't really news to anyone, as I've heard about these concerns before. But here's an interesting read/watch about selenium in the Elk Valley, done by an environmental protection research group. Print article contains a video link as well.
https://thenarwhal.ca/for-decades-b-c-failed-to-address-selenium-pollution-in-the-elk-valley-now-no-one-knows-how-to-stop-it/
I appreciate the economic importance of Teck to the region, so hopefully they can find a way to mitigate this issue, but quick. Not sure where the mine proposal is at for Crowsnest Pass these days, but it certainly raises alarm bells for me about potential mine impacts this side of the divide too.