The Baltic Sea is heavily polluted with persistent organic pollutants (POPs) such as polychlorinated-pdibenzodioxins and dibenzofurans (“dioxins”) and PCBs. The pollution impacts the levels in biota, e.g. it is well-known that the concentrations of dioxins and dioxin-like PCBs in fatty fish from the Baltic Sea are high and occasionally exceed the
EU quality standard for food and feed. Recent studies have demonstrated declining dioxin levels in coastal and offshore sediments during the last decades1, but corresponding declines are not seen in Baltic herring2. The current understanding
of POPs accumulation in pelagic fish is that the concentrations in fish are positively correlated to the dissolved POPs concentrations in the water, which in turn may be linked to sediment pore water levels. We investigated these relationships in a coastal sediment-water-biota system of Gulf of Bothnia and found linear relationships3. Here, we
synthesize the results from this study3 and a number of other Baltic Sea research projects1-2,4-5 to better understand the links between sediments, bottom water and pelagic biota. The results are discussed in relation to spatial and temporal
trends of the Baltic Sea environment, current dioxin sources, and suggestions for monitoring strategies for the Baltic Sea dioxin pollution.
The Baltic Sea is heavily polluted with persistent organic pollutants (POPs) such as polychlorinated-pdibenzodioxins and dibenzofurans (“dioxins”) and PCBs. The pollution impacts the levels in biota, e.g. it is well-known that the concentrations of dioxins and dioxin-like PCBs in fatty fish from the Baltic Sea are high and occasionally exceed the
EU quality standard for food and feed. Recent studies have demonstrated declining dioxin levels in coastal and offshore sediments during the last decades1, but corresponding declines are not seen in Baltic herring2. The current understanding
of POPs accumulation in pelagic fish is that the concentrations in fish are positively correlated to the dissolved POPs concentrations in the water, which in turn may be linked to sediment pore water levels. We investigated these relationships in a coastal sediment-water-biota system of Gulf of Bothnia and found linear relationships3. Here, we
synthesize the results from this study3 and a number of other Baltic Sea research projects1-2,4-5 to better understand the links between sediments, bottom water and pelagic biota. The results are discussed in relation to spatial and temporal
trends of the Baltic Sea environment, current dioxin sources, and suggestions for monitoring strategies for the Baltic Sea dioxin pollution.