This would seem to be a trick question but for a number of lakes in Canada, it will mean a loss of protection.
Under changes to the regulations (Schedule 2) of the Fisheries Act, a lake can be changed into a tailings impoundment area. At that point it no longer is considered a natural body of water which, if toxic materials were dumped in it, would be protected by that same Fisheries Act.
There are now a dozen lakes and rivers in Canada that have already begun the process of being "reclassified" as toxic dump sites for mining companies. Sandy Pond in Newfoundland will now be a place where Vale Inco, a Brazilian company, can dump 400,000 tonnes of toxic waste a year over the next 15 years.
Vancouver-based Taseko Mines wants to develop an open pit mine 125 kilometres west of Williams Lake, British Columbia. They will drain the Textan Biny (Fish Lake) and stockpile rock waste and use Fish Creek and Little Fish Lake to dump their toxic tailings. These tailings pond would clearly poison local water supplies and wipe out fish populations as Taseko River is connected to Little Fish Lake.
As the mining industry makes staggering profits into the billions of dollars, it could certainly afford to use technologies to manage mine waste in a sustainable way. The Canadian Federal Government appears to be complicit in this by allowing the mining industry to degrade our pristine water resources for short-term gain.
Canada’s public freshwater ecosystems are now at risk of being toxic waste dumps rather than being diverse habitat. When fresh water is valuable as drinking water sources, it seems inappropriate to eliminate them now when climate change is looming.