The effect of mine tailings on levels of heavy metals in seawater

Changes in levels of heavy metals in seawater resulting from the addition of mine tailings were studied using plastic enclosures. Nominal concentrations of 10 mg l super(-1) and 100 mg l super(-1) of mine tailings from a B.C. molybdenum mine were added, and the metal levels were followed together with sedimentation rates, particle size distribution and other oceanographic and biological time-series parameters over sixteen days. No substantial elevation in levels of zinc, cadmium and copper was observed in the tailing bags compared to that in a background control bag with no addition of tailings. Lead showed a substantial increase in seawater following tailing addition and its removal apparently was with detritus settling following a plankton bloom, and inorganic settling of fine tailing particles.