Collaborators: Dr. Michael Douglas (Charles Darwin University)
Dr. Chris Humphrey (eriss) Dr. Rick van Dam (eriss) Ms. Alicia Hogan (eriss)
Magnesium sulfate (MgSO4) is a common contaminant at mine sites. This is also true for the Ranger Uranium Mine (RUM) where magnesium sulfate is a major constituent of waste waters arising mostly from erosion of waste rock. A discharge containing leachate with elevated solutes from this waste rock flows into Magela Creek within the boundary of Kakadu National Park in the Wet/Dry tropics of Australia's Northern Territory. Although this chemical has received very little ecotoxicological assessment and it is generally assumed that both magnesium and sulfate are relatively benign in their ecological effects, results of surveys of local water bodies have shown changes in macroinvertebrate community structure correlating with elevated magnesium sulfate concentrations. A study was therefore initiated to determine the ecological effects of magnesium sulfate in these freshwater ecosystems. The objective of this study is to derive a magnesium sulfate concentration safe to aquatic ecosystems of Magela Creek and which should not be exceeded in mine waste-water releases to the creek. Additionally, criteria for inclusion in the Australasian Water Quality Guidelines will also be developed. More information... | 
