Operational monitoring of the Høyangsfjord in 2018. Monitoring on behalf of Hydro Aluminium Høyanger and Nyrstar Høyanger

Summary

NIVA has conducted operational monitoring of the Høyangsfjord on behalf of Hydro Aluminium Høyanger and Nyrstar Høyanger. 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 companies discharges of contaminants to the Høyangsfjord. Levels of polycyclic aromatic hydrocarbons (PAH), fluoride and metals were analysed in blue mussel from five stations. Limit value (EQS) for mercury was exceeded at all stations. Mercury is one of the priority substances in the Water Frame Directive. The chemical status of all stations was therefore classified as "not good". There has been a reduction in concentration of mercury in blue mussel from 2015 to 2018 for three of the stations. The reduction was most evident in blue mussel from the innermost station (Sandvika), where the concentration of mercury was reduced by one third. Blue mussels from Sæbøneset had the lower concentration of mercury than the other stations in the Høyangsfjord. The concentration of mercury in blue mussels from Sæbøneset was at the same level in 2018 as in 2015. There were no exceedances of limit values for any of the PAH compounds. The concentrations of PAH compounds were low, but there was a small increase in concentration of PAH16 from 2015 to 2018. Blue mussels collected by the old landfill at Sæbøneset had slightly higher concentrations of fluoride than the other stations.