Tiltaksorientert overvåking av Årdalsfjorden i 2018. Overvåking for Hydro Aluminium Årdal

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 was designed based on the company’s discharges of contaminants to the Årdalsfjord. Levels of polycyclic aromatic hydrocarbons (PAH), and metals were analysed in blue mussel from five stations. The innermost station is located near the smelter and the outlet of discharges to the fjord. The concentration of metals and PAH compounds in blue mussel was generally low, but at the innermost station in the fjord, the limit value for two PAH compounds was exceeded, the priority substances benzo(a)pyrene and fluoranthene. The chemical status of this station was therefore classified as "not good". There were no exceedances of the limit values for the other mussel stations, and they were therefore classified as "good chemical status". There were no exceedances of the limit value for the river basin specific pollutants. There has been a considerable reduction in concentration of PAH compounds in blue mussel from the inner part of the Årdalsfjord. The concentration of PAH16 in blue mussel at the innermost station had a reduction of approximately 50 % from 2017 to 2018.