Based on extensive testing of the surface and groundwater of the area, which naturally leach metals from the surrounding rock, and the results of humidity cell tests on waste rock and cemented tailings, the most persistent elements exceeding groundwater and surface water standards are arsenic (As), selenium (Se), thallium (Tl), and strontium (Sr). Other elements, including copper (Cu), lead (Pb), nickel (Ni), mercury (Hg), cadmium (Cd), and zinc (Zn), could be of concern if waste rock were not properly managed. Fortunately, responsible management minimizes the amount of leaching of these elements into site water during the operation, and reverse osmosis water treatment removes all of them.