Operational monitoring of the Årdalsfjord in 2017. Monitoring on behalf of Hydro Aluminium Årdal

Summary

NIVA has conducted operational monitoring of the Årdalsfjord on behalf of Hydro Aluminium Årdal. The monitoring programme was prepared in accordance with the water frame directive and approved by the Norwegian Environmental Agency. The programme is designed based on the company’s discharges of contaminants to the Årdalsfjord. Levels of polycyclic aromatic hydrocarbons (PAH), fluoride and heavy metals were analysed in blue mussels. Blue mussels from the innermost station in the Årdalsfjord were in “not good chemical status” because of concentrations of the PAH compounds fluoranthene and benzo(a)pyrene that exceeded the environmental standards (EQS) for these substances. The four other stations had “good chemical status”, and had low concentrations of PAH compounds. The innermost station had slightly elevated concentration of fluoride, and also concentrations of cadmium, nickel, lead and zinc that were above high background concentrations for blue mussel. In November 2016, diesel was spilled into the Årdalsfjord at Årdalstangen. The high concentrations of PAH compounds found in blue mussels from the innermost station was probably caused by the diesel spill incident.