Operational monitoring of Karmsundet in 2019 on behalf of Hydro Aluminium Karmøy

Summary

NIVA has conducted operational monitoring in the Karmsund in 2019 on behalf of Hydro Aluminium Karmøy. 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 sea. Levels of polycyclic aromatic hydrocarbons (PAH), arsenic, cadmium, copper, chromium, lead, mercury, nickel and zinc were analysed in samples of blue mussel from three stations. Highest concentrations of PAH-compounds were found in blue mussels from Høgevarde, located near the northern settling basin. Blue mussels from Høgevarde had concentration of benzo(a)pyrene that exceeded the limit value (EQS) for this priority substance. Chemical status of this station is therefore classified as “not good”. No concentrations in blue mussels from Helgelandsvika and Bygnesvågen exceeded EQS of priority substances. Chemical status of these stations is therefore classified as “good”. There were no exceedances of EQS for the river basin specific substance benzo(a)anthracene. Blue mussels from Høgevarde had lower concentration of PAH-compounds in 2019 than in 2017. The concentration PAH-compounds was about half the concentration in 2017. There were elevated concentrations of several heavy metals in blue mussels from Høgevarde. That station also had highest concentrations of heavy metals.