Sustainable Minerals Institute
Faculty of Health, Engineering and Science
School of Natural Sciences/Mine Water and Environment Research Centre
Water quality contaminants include a range of naturally occurring chemicals that can cause degradation of aquatic ecosystem water values when concentration ranges exceed biological tolerances. Both acid and metalliferous drainage (AMD) and acid sulfate soil (ASS) can increase contaminant concentrations through reduced pH and increased solute concentrations especially of toxic metals and metalloids. Water quality guideline criteria are typically used to maintain existing end use value objectives when managing AMD/ASS-affected waters. However, surface and ground waters of catchments comprising mining resources often show elevated solute concentrations in baseline conditions due to their unique geologies. From an AMD and ASS risk assessment perspective, regional water quality may therefore be unique and locally-relevant such that site-specific water quality guidelines may therefore be required to most reasonably manage water quality objectives. We provide case study examples from iron ore and coal mining from the Western Australian regions of the Pilbara, and the South-west to show that defining water quality criteria for closure is more than just using generic national guidelines, but an explicit consideration of the baseline regional bio-physico-chemical context.