Determination of the acute toxicity of mine tailings from Nussir. ASA to the marine alga Skeletonema costatum, the marine copepod Tisbe battagliai and the polychaete Arenicola marina

The acute toxicity of mine tailings from Nussir ASA have been determined. The concentrations of the mine tailings ranged from 100% v/v to 1% v/v and the mine tailings were diluted with a clean reference sediment obtained from NIVA’s Marine Research Station in Solbergstrand plus a reference sediment control and were mixed with clean reference seawater at a ratio of 1:10 v/v mine tailings:water. Three different species were used for the toxicity assessments, representing different trophic levels in the environment, comprising of the alga Skeletonema costatum, the copepod Tisbe battagliai and the polychaete worm Arenicola marina. The copepod and algal tests were performed on overlying water taken from the test system prior to commencement of the polychaete worm test. There were no effects observed on the algae at any concentration up to and including 100% v/v. There was a slight effect (35% mortality) observed in the T. battagliai test at the 100% v/v concentration and a 50% effect (mortality) at the 100% concentration in the A. marina test. Therefore the Lowest Observed Effect Concentration (LOEC) for the mine tailings is 100% v/v and the No Observed Effect Concentration (NOEC) for this study is 32% v/v.Øystein Rushfeldt, Nussir AS