@josie The problem isn’t ad populum, it’s a failure to properly apply vox populi. A person’s right to participate in a decision is directly proportionate to the amount the decision will affect hir. In this case, the problem is that while the town will be affected, so too will those who use the contaminated water, and so they, too, must be permitted a voice in the decision.
Human beings are logical creatures. We don’t act without reason. Voting in favour of one’s logical self-interest is only a problem when the distribution of executive decision-making power is vested in only some of the people involved. The anarchist solution has always been to show people that their own long-term best interests are served when everyone involved is given the opportunity to shape policy to the degree that they are involved at all.
To the OP: If you want some serious bonus points, you might try working a summary of the exchange that @josie and I just had into your essay.. It will show you understand not only the material, but the subtext of the material.