The mining company Sydvaranger Gruve AS (SVG) started in 2009 the production of iron ore concentrate, after the business had been stopped since 1997. The production is authorized under the Pollution Control Act of 23 April 2008. The discharge permit was amended in 2011 (discharge permit from 6. April 2011), 2012 (discharge permit of 24. May) and 2013 (discharge permit of 3. December). In the discharge permit of 24th May 2012, SVG is allowed to continue the use and release of water treatment chemicals with the active substance polyDADMAC and increased use of water treatment chemicals, i.e. 50 tons per year of polyacrylamide and 10 tons per year of polyDADMAC. The Environment Directorate (then Klif) did however require that SVG should conduct assessments of possible degradation products and any long-term toxic effects of chemicals in the discharged tailings. This document reports the results of studies of chronic toxicity and leakage potential of water treatment chemicals (mainly polyDADMAC ) used by SVG in the coagulant Magnafloc LT38 . The report is meant to fulfill the requirements set for SVG by the Environment Directorate (permission of 24. May 2012) in order to continue the discharge of polyDADMAC and increase the use of water treatment chemicals.