There are water around mines that will be toxic to human life until the sun collapse and the earth burns up. People will have to be aware of those dangers for as long human exist, unless humans mutate enough to tolerate lead and sulfur in their fresh water.
How should we communicate to those people of those dangers?
We can filter it out, but unless people know that the water is toxic then they might still be harmed. How do we inform the people of the future of the dangers that contaminated fresh water has, and how do we do that for billions of years into the future?
How should we communicate to those people of those dangers?