I can remember back in the 1960s when I was a kid were told to not eat the snow. (I live in the Missouri)Why?,because of the above ground nuclear testing.
And when hiking in the mountains, never drink the water from a crystal clear stream. Moose or bear probably up stream.
I know you never want to eat/drink snow with a pinkish tinge because it has a harmful bacteria growing in it. But that’s usually just on the surface, it you scoop it off the white snow underneath is good.