and we've collected enough arsenic from a single mine to kill every human on the planet 300 times over in one spot- what's your point? That because we screwed up one spot we should give up?

Source: https://en.wikipedia.org/wiki/Giant_Mine

Not sure why people buried your post, but many water-soluble metal salts are pretty toxic to animals and people.

In areas with natural Arsenic accumulation (or Acid rain run off), farmers will sometimes place rusting iron equipment in the water ways to reduce metals accumulating in the topsoil.

With low rainfall the evaporated well-water problem can certainly be a serious concern. =3