Earlier this week, I pointed out that human activity has been putting hormone-like chemicals into the water. Don't panic. Discovery news has a solution.
Alfalfa and similar grasses absorbs this pollution, and is not often eaten by humans. Rabbits breed fast enough that we could have a disposable batch of rabbits to eat this, live their short lives, and produce pelts when they end. Running it through the alfalfa partially breaks it down, and feeding that alfalfa to rabbits will break it totally down. In theory, the rabbits would be safe to eat. (In practice though, I think they will wind up as dog or cat food.)
And if water treatment plants need to include a small alfalfa farm, I think they could do this. Water would be so much cleaner, for very little added cost.