Concentrations and origin of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in sediments of western Spitsbergen fjords (Kongsfjorden, Hornsund, and Adventfjorden)

Contaminant profiles in sediment cores represent valuable natural archives of environmental contamination, by which contaminant sources and historical changes in contaminant input and cycling may be recognized. In the present study, we discuss the sedimentary profiles and historical trends of organic contaminants-polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs)-in three fjords of the Svalbard archipelago differing in environmental conditions and anthropogenic impact. The obtained results revealed no significant differences between the fjords Hornsund and Kongsfjorden, in the average levels of the analyzed contaminants. Levels ranging from 0.05 to 1.47 ng/g d.w. for Sigma 7 PCBs and from 37.3 to 1973 ng/g d.w. for Sigma 12 PAHs were measured. The observed spatial and temporal differences in contaminant levels are rather related to local variations in the fjords associated with the location of sampling stations. Higher concentrations of the Sigma 7 PCBs exceeding 1.00 ng/g d.w. were measured in sediment cores collected in the inner parts of both fjords, which remain under the influence of melting glacier outflows. Important concentrations of these contaminants were noticed in layers deposited recently, suggesting intensive supply of these substances from secondary sources. The observed levels are generally low and well below known established no effect levels. Only the concentration of fluoranthene exceeded the threshold effect level at several sampling stations. Moreover, fluoranthene concentrations in almost all Adventfjorden sediment layer samples were above probable effect levels, which can indicate a risk of adverse effects in exposed benthic organisms. The fluoranthene/pyrene and phenthrene/anthracene ratios, which are used for identification of hydrocarbon sources, suggest a dominance of PAHs of pyrolytic genesis in Kongsfjorden and Hornsund. In Adventfjorden, hydrocarbons of petrogenic origin were predominant. However, other sources like coal dust from stores on land are also possible at this location.