Sure, it's your land.
> What happens when 10 years later it starts leaching into the soil and poisoning nearby streams and farms?
Those impacted landowners now have a tort claim against you, which they should pursue.
> What about the animals who eat on my land and then run back into the forest where they get shot for someone else's dinner, and that someone else ends up consuming elevated levels of heavy metals?
They now have a tort claim against you, which they should pursue.
> What about the person who buys the land from me? Do I have to disclose the presence of the waste to them?
Yes, you should. If you don't, the purchaser now has a tort claim against you, which they should pursue.
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I know I'm being a bit trite with the above, but I mean no offense. The difference here is one of strategy, not base ideas. I (and other libertarians) believe that people who harm others through their action should be responsible for that harm. Proponents of the EPA believe that people should be limited by government regulation to a minimal level of harm.
I'll also grant that, prior to the EPA, the tort system in the US was ineffective at resolving these issues. I don't believe that was a problem with the process itself; it was (and remains) a problem with the courts.