Share Mikisew Cree member Robert Grandjambe checks his nets on Lake Athabasca in Fort Chipewyan, Alta., located on the world's largest inland delta in Wood Buffalo National Park. The park may become listed as a UNESCO World Heritage Site in Danger due to the impacts of the Alberta oilsands and major dams on the Peace River. Photo: Louis Bockner / Sierra Club BC Leaks from toxic tailings ponds in the oilsands and dams on the Peace River in B.C. and Alberta are moving Canada’s largest national park closer to being placed on an international list of world heritage sites in danger, according to a report released Monday.