Condition monitoring in the water column 2005: Oil hydrocarbons in fish from Norwegian waters

This report has been prepared by Institute of Marine Research (IMR) & University of Stockholm (UoS) on behalf on the offshore petroleum industry operators on the Norwegian Continental Shelf as part of the authority requirements in the Health, Safety and Environmental regulation (Activity regulation). The objectives for this study have been: 1. Determine to what extent fish from the oil installation areas at Tampen and the Halten Bank contain elevated levels of petroleum hydrocarbons compared with fish from reference areas at the Egersund Bank/Ling Bank and in the Barents Sea by measurements of NPD/PAH in fish muscle. 2. Comparison of NPD/PAH bile metabolites in fish from Tampen compared with fish from Egersund Bank/Ling Bank 3. Study possible genototoxic effects in fish from Tampen compared with fish from Egersund Bank/Ling Bank by measurements of hepatic DNA adducts. 4. Document to what extent discharges of alkylphenols in produced water cause estrogenic effects in fish from Tampen by measurements of alkylphenols in muscle and liver, and vitellogenin in plasma. Di- and polyaromatic hydrocarbons (NPD/PAH) have been analysed in muscle of cod and haddock caught in the North Sea at Ling Bank/Egersund Bank (reference), Tampen, Halten Bank and Barents Sea (reference), autumn 2005 and concentrations found to be below levels of quantification (LOQ) for fish sampled from all regions. Cod sampled at the Ling Bank/Egersund Bank in the Southern part of the North Sea had the same levels of PAH metabolites in bile as cod sampled from the Tampen region. Haddock demonstrated significantly higher levels of fluorescence for all three wavelength pairs measured, indicating a higher levels of 2-, 3-, 4- and 5-ring PAHs for haddock sampled in the Tampen region compared with haddock from the Ling Bank/Egersund Bank region. Saithe, on the other hand demonstrated higher levels of 2- and 3-ring compounds at the Ling Bank/Egersund Bank compared with fish sampled at Tampen. Overall, the highest levels of PAH metabolites in bile were measured in haddock. DNA adducts were analyzed in liver of cod, haddock and saithe at Tampen and from Ling Bank/Egersund Bank (reference site). In both areas the highest levels of DNA adducts were measured in haddock. The percentage of individuals with detectable adducts was also higher in haddock than for the other species. Haddock from Tampen had significant higher DNA adduct levels compared with haddock from Egersund Bank/Ling Bank (Mann-Whitney test), indicative of more PAH exposure in this region. Higher levels of DNA adducts in haddock caught at Tampen compared with the Egersund Bank have earlier been reported by Klungsøyr et al. (2003). Significant differences were not found for cod and saithe collected from the same areas. Analyses of alkylphenols in cod liver, haddock liver and herring muscle from Ling Bank/Egersund Bank and Tampen regions demonstrated levels below limits of detection (LOD) for all stations. The absence of alkylphenols in fish is in line with the results from the 2002 monitoring (Klungsøyr et al., 2003), and it supports the risk assessment carried out by Myhre et al. (2004) that stated that the risk for estrogenic and reproductive effects in fish after alkylphenols exposure from produced water discharges is very low. There were no differences in VTG concentration in plasma of cod caught at Tampen compared with Ling Bank/Egersund Bank that could not be explained by differences in size and sexual maturation