If you think turning lead into gold is hard, try getting toxic chemicals out of river mud. But luckily, there are real alchemists all around us—plants, animals, and microbes that are constantly breaking apart and remaking molecules (or, eating and digesting). This is a book about a creative biologist who found a way to put this natural chemical factory to work to clean up toxic chemicals and oil from a polluted river, using a series of tanks full of creatures who thought of big fat sludge molecules as food. Now, that’s alchemy!