Professor John Ashley Scott’s house is situated on the shores of a lovely lake in Sudbury, Ontario, a short drive from Laurentian University, where he works in the Bharti School of Engineering. The lake has been in the local news quite a lot recently, and not for its reputation as a popular recreation spot. “At the end of it, there’s an old abandoned gold mine from the 1930s,” explained Scott. “For the last 80-odd years, cyanide and arsenic has been leaking into the lake.” The pH of the water nearest the mine’s rudimentary tailings pit is a dismal 2.5, making it inhospitable to fish and the water unsafe to drink.