Ecotoxicity limitations following liming and nutrient enrichment to remediate acid mine lakes

Clint McCullough (MiWER), Luke Neil (Curtin), Mark Lund (MiWER), Jess Sackmann (CWR, UWA), Dr. Anas Ghadouani (CWR, UWA), Dr. Yuri Tsvetnenko (Curtin), Dr. Jim Ranville (DCG-Colorado School of Mines), Prof. Louis Evans (Curtin)

Is liming and enhanced primary production able to reduce ecological toxicity and increase biodiversity of Collie lakes?

Twelve 1,200 L mesocosms at ECU have been filled with a 40 mm layer of lake sediment from the bottom of the fast river-filled Lake Kepwari. This representative sediment layer has then been covered with Lake Kepwari water. Treatments have been allocated in a randomised two-way factorial design to test the effects of liming, phosphorus enrichment and combined liming and phosphorus amendment on different aspects of the AMD water chemistry, ecotoxicity and ecology.

                             Not limed    Limed

No nutrients    U U U    U U U

Nutrients            U U U    U U U

Figure: Experimental Design

Photo: Collecting sediment from Lake Kepwari


Photo: The mesocosms back established at ECU

This was a collaborative multidisciplinary project with co-supervised students at Curtin University of Technology and University of Western Australia. The Edith Cowan University team examined water chemistry, sediment and periphyton dynamics, including the effect of liming and enhanced primary production upon dissolved heavy metal and nutrient concentrations, alkalinity and pH. Jess Sackmann examined correlations between phytoplankton community water quality, and Luke Neil examined the effect of different treatments on aquatic ecotoxicity between each other and over time.

Funding:

Part of L. Neil’s Ph.D. project and J. Sackmann’s Honours Project. Partially funded by Curtin, Edith Cowan, UWA and the Centre for Sustainable Mine Lakes.

Outputs:

Neil, L. L. (2008). Bioassay assessment of mine pit lake water for aquaculture and biodiversity conservation, Ph.D. thesis, Curtin University of Technology, Perth, Australia. 298pp. link

Neil, L.; McCullough, C. D.; Lund, M.A.; Tsvetnenko, Y. & Evans, L. (2009). Bioassay toxicity assessment of mining pit lake water remediated with limestone and phosphorus. Ecotoxicology and Environmental Safety. 72: 2,046-2,057.link (Highlighted article).

Neil, L.; McCullough, C. D.; Tsvetnenko, Y. & Evans, L. (2006). Toxicity assessment of limed and phosphorus amended mine pit lake water. RACI/ASE Interact 2006 conference. Perth, Australia 24-28 September. PDF

Sackmann, J. (2006). The effect of experimental liming and nutrient addition on phytoplankton of an acidic mine lake, B.E. (hons) thesis, University of Western Australia, Perth, Australia. 50pp.

Remediation of waters from a south-west Australian acid pit lake with oxic liming and an aerobic wetland

Clint McCullough (MiWER), Mark Lund (MiWER), David Bills (Griffin Coal)

Does treatment with oxic liming and an aerobic wetland remediate mine waters from a new acid pit lake?

A mine water treatment system was constructed at Griffin Coal Mining Company Limited in Collie Western Australia, to remediate acidified mine lake water from the nearby Chicken Creek pit lake (pH 3, containing approximately 8 million m3 of water) and make it suitable for cultivating plants or fish.

The first part of pit water treatment is a two-stage liming system utilising a fluidised bed of limestone. At each stage of liming there is a settling pond to remove particulate iron- and aluminium oxyhydroxides. From here the limed water gravity-feeds back to the lake though 5 ha constructed aerobic “polishing” wetland.

Photo: Fluidised liming of Chicken Creek pit lake water


Photo: Aerobic polishing of fluidised Chicken Creek pit lake water

This study is evaluating the way in which fluidised liming and aerobic wetland treatment can remediate pH and elevated metal concentrations in water from a typical recently groundwater-filled acid pit lake of Collie. Both water chemistry analyses and toxicity teas are being undertaken to evaluate water quality at each stage of treatment in order to better understand the processes taking place in this treatment system. The conclusions and recommendations of this project will enable better design of such systems for this mining region.