Determination of the acute toxicity of process chemicals in mine tailings from Nordic Mining ASA to the marine alga Skeletonema costatum, the marine copepod Tisbe battagliai and the polychaete Arenicola marina

The acute toxicity of process chemicals applied to mine tailings at Nordic Mining ASA have been determined. The concentrations of the process chemicals applied to the sediment ranged from an order of magnitude lower than the Environmentally Relevant Concentration (ERC) to an order of magnitude higher with 2 intermediate concentrations and appropriate controls. There were no effects on any of the organisms at the ERC of process chemicals. There was a statistically significant effect at the 3.2 times ERC on the growth of the algae but not in the copepod or polychaete worm tests. The 10 times concentration also had an effect on growth of the algae and caused a complete kill in the polychaete worms and crustacean (LC100). Therefore the Low Observed Effect Concentration (LOEC) is 3.2 times the environmentally relevant concentration of process chemicals in the mine tailings. The No Observed Effect Concentration (NOEC) for this study was at the ERC of process chemicals in the mine tailings. Therefore, the concentration of process chemicals in the mine tailings being used by Nordic Mining ASA should not cause acute toxicity in the environment