Combustion processes are considered to be the main source of the dioxin emission in the Baltic region. Pentachlorophenol (PCP) and its derivatives, pentachlorophenyl laurate (PCPL) and sodium pentachlorophenate (NaPCP) are known as precursors of dioxins. The research was conducted to obtain the first data on the concentration of PCDD/Fs and PCP in the bottom sediments of the Port of Gdansk. Toxicity (the Microtox® test) as well as several sediment parameters have been examined.In the surface layer of bottom sediments from the Port of Gdansk, all congeners of PCDD/Fs have been detected using GC-MS/MS. The positive correlation between toxicity and physicochemical properties of the analyzed bottom sediments confirms that these parameters are important in terms of environment contamination.

Toxicity assessment of environmental compartments, in particular sediments as a highly complex matrix, provides a more direct way to assess potential adverse effects of pollutants present in a sample in contrast to chemical analysis estimating only a quantitative level of xenobiotics. Interactions between chemicals, formations of derivatives and the influence of chemical properties of sediments such as the organic matter content causing the intensified sorption of hydrophobic pollutants suggest that a traditional approach to the sediment quality, based only on chemical analysis may be insufficient. The presented study describes the vertical and horizontal variability of toxicity of Gdańsk Basin sediments. Based on 128 surface sediments samples and using geostatistical methods, a prediction map for the EC50 parameter was created. This allowed the evaluation of the toxicity of the surface sediment layer at any selected point of the study area. The applied analysis can be functional for many other locations worldwide. In the present study, the hypothesis about the location of toxic sediments in the vicinity of Gdańsk Deep, outer Puck Bay and close to Vistula River mouth was further confirmed.

The study presents the analysis of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/F) and dioxin-like polychlorinated biphenyls (dl-PCB) in fish and seabirds from the Baltic Sea area and the Arctic region (the Svalbard Archipelago). Long-time studies revealed no significant temporal trends in PCDD/F and dl-PCB concentrations in fish from the Baltic Sea. Trace amounts of PCDD/F were detected in the Arctic fish as an evidence of their anthropogenic sources from the temperate zone, however congener profile in the cod was entirely different than in the Baltic fish. On the contrary, both concentrations and profiles of dl-PCB were comparable in cod from the Baltic Sea and from the polar region. PCDD/F`s congener profile in African penguin`s tissues breed in captivity and fed only by herring exhibited a clear resemblance to the profiles measured in herring. This indicates a relevant impact of diet (fish) on PCDD/F`s level in seabirds. Diet impact on the further transfer of these xenobiotics in the trophic chain, evidenced in the presented study, appears to be of the particular relevance due to the human health.

The Vistula River plays an important role in the supply of autochthonous and allochthonous material to the Gulf of Gdansk. The suspended particulate matter (SPM) of fluvial origin is considered to constitute a specific sorbent for halogenated organic compounds due to their lipophilic characteristics and relative solubility. Because there are many factors affecting the input of SPM into the estuarine environment of the Gulf of Gdansk, e.g. hydrological characteristics of the Vistula River, it became necessary to verify whether the same processes may affect a discharge of organic contaminants. The study presents an approach to the assessment of temporal trends in SPM concentration in the Vistula River discharged into the Gulf of Gdansk as well as the analysis of pentachlorophenol (PCP), a commonly used agricultural biocide, a precursor of dioxins in either dissolved or particulate phases in the river (the Vistula River) and sea waters (the Gulf of Gdansk). The study revealed that the hydrological characteristics appear to influence a load of SPM. However, the discharge of PCP is additionally related to the environmental conditions, physicochemical properties of the compound and the sorbent, affecting the partitioning of PCP into dissolved and particulate phases.

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