Sammendrag
NIVA has conducted operational monitoring of Husebybukta on behalf of Alcoa Lista. 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 Husebybukta. Levels of polycyclic aromatic hydrocarbons (PAH), and metals were analysed in blue mussels from one station and in common limpets from four stations. Monthly water samples were taken in Husebybukta and analysed for lead and cadmium.
Limit values (EQS) were exceeded for the priority substances benzo(a)pyrene and fluoranthene in samples of common limpets from Ytre Tjuvholmen and in blue mussels from Haugestranda. The chemical status of these stations are therefore classified as "not good". There were no exceedances of limit values of priority substances for the other stations. The chemical status of the other three biota stations is therefore classified as "good". Limit values for annual average (AA-EQS) were exceeded for lead and cadmium in water samples at station H1 in Husebybukta. The chemical status of this station is therefore classified as "not good". Limit value of the river basin substance benzo(a)anthracene was exceeded in blue mussels from Haugestranda. Like in 2015, the stations closest to the discharge from Alcoa Lista had highest concentrations of priority substances. The concentration of PAH16 was lower in blue mussels from station Haugestranda in 2018 than in 2015.
There were some elevated levels of fluoride at four of the stations in this study. The stations were therefore classified as Class II "moderately polluted" by fluoride, and one station was classified as Class I "negligible - slightly contaminated" by fluoride.
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