Operational monitoring of Tromøysundet in 2019. Monitoring on behalf of Fiven Norge AS avd. Eydehavn.

Summary

NIVA has conducted operational monitoring of water bodies by Eydehavn and Tromøysundet on behalf of Fiven Norge AS. avd. Eydehavn. 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 water body Tromøysundet-Bekkevika. Samples of blue mussel from seven stations were analysed for arsenic, lead, cadmium, copper, chromium, mercury, nickel and zinc. Of the heavy metals, there is EQS for concentration in biota only for the priority substance mercury. Hence, the concentration of mercury is crucial for classifying chemical status of the blue mussel stations. No concentrations of mercury exceeded the EQS for any of the blue mussel stations. Chemical status is therefore classified as “good” for all stations in the monitoring project. To assess the level of contamination for the other heavy metals, the concentrations have been compared to estimated values for Norwegian high reference concentration (PROREF – provisional high reference concentrations). Five of the stations had elevated levels of copper, with highest concentrations on stations farthest away from the discharge from Fiven. This indicates that there are also other sources to copper pollution of this area. One blue mussel station in Bekkevika also had elevated level of lead. The outermost station had elevated concentrations of arsenic, copper and zinc, and is therefore not a suitable reference station.