Every five years, water quality is assessed in 32 inland lakes that are greater than 8 hectares in surface area. Samples are collected via helicopter and three key stressors (acidification, eutrophication and metal loading) are assessed using nine parameters [pH, aluminum, calcium, total nitrogen, total phosphorus, dissolved oxygen concentration, iron (Fe), cadmium (Cd) and lead (Pb)]. YSI measurements and Secchi disk measurements are also taken. Samples are sent to the National Laboratory for Environmental Testing (NLET), Burlington, ON, to test for metals and to Natural Resources Canada, Sault Ste. Marie, ON, to test for nutrients.