Biomarker responses in fish from Frierfjorden and Eidanger

Abstract

There have been high inputs of dioxins and dibenzofurans into the Frierfjord. The aim of the project reported here was to clarify whether there were observable responses in fish collected from Frierfjord and the adjacent Eidangerfjord that could be associated with exposure to dioxins and dibenzofurans. Three species of fish, Atlantic cod (Gadus morhua), trout (Salmo trutta) and flounder (Platichthys flesus) were sampled during three field campaigns. Other results have shown that the two areas did not differ by more than a factor 2 to 3 in dioxin exposure. In both cod and trout, individuals from Frierfjord generally had higher activity and level of cytochrome P4501A than fish from Eidangerfjord, indicating that the 2-3 times higher dioxin exposure causes increased phase-I enzyme activity. Cod and flounder from both areas had much higher hepatic cytochrome P4501A activity than that seen in reference areas. Differences between the three species were apparent for both phase-II and antioxidant enzyme responses. It can be concluded that dioxin inputs in to the fjord does affect fish in the area and that the effects decreased with decreasing exposure.