PRELIMINARY INVESTIGATION OF ARSENIC AND COPPER IN PLANTS AND TAILINGS AT TELFER GOLD MINE

The successful establishment of revegetation using native plants is crucial to help phytostabilization of mine tailings. To assess arsenic (As) and copper (Cu) pollution levels and the feasibility of using native plants in rehabilitation of mine areas, a preliminary investigation was conducted to measure As and Cu in mine wastes and native plants at Telfer Gold Mine. The top layer of soil/mine wastes and leaf samples of native plants (Acacia spp, Dampiera sp, Eucalyptus camaldulensis, Maireana platycarpa) were collected at the mine sites (tailings) and in the native bush outside the mine (control) and analysed for pH, total and extractable elements (including As and Cu) in soils and total concentration of elements (including As and Cu) in plants. The pH was significantly lower and the total concentrations of As and Cu greatly higher (more than 2 orders or magnitude) in tailings compared to the control soil. The extractable Cu concentrations were significantly higher in tailings than the control soil and not influenced by the type of extractant used. The extractable As concentrations were low in tailings and not detectable in the control soil. The concentrations of As and Cu in tailings exceeded the thresholds for both ecological and health investigations based on the assessment levels for soil, sediment and water for contaminated sites management (Department of Environment and Conservation, Western Australia). The concentrations of As and Cu in plant leaves were higher in mine tailings than control (the reverse was true for As in Acacia sp-1). The concentrations of As and Cu in plant leaves were very different among the plant species in the same sites. The concentrations of As and Cu in leaves of plants growing on tailings were above the normal ranges (but mostly below or within the critical phytotoxicity level) and at the maximum dietary intake levels for livestock. The relatively higher concentrations of As and Cu in un-washed leaves compared to leaves washed (1% v/v acetic acid) before analysis indicated that As and Cu could be transferred from mine site to the surrounding environments in dust. Further studies are needed to develop the science-based knowledge on how to minimise or mitigate the relevant environmental risks.