The paper presents changes in concentration levels of dioxin-like compounds that can be observed over the course of four study seasons in water samples collected from the Arctic watershed of Svalbard. The conducted analysis involved anthropogenic and natural factors that may affect the concentration of PAHs in the study samples of water. An attempt is made to indicate the emission source of the compounds being deposited and to identify the extent to which the substances under analysis actually affect the Arctic ecosystems. Moreover, the work employs the following: diagnostic ratios PAHs, air masses backward trajectory analysis, Lidar observations and land relief analysis in order to provide a multi-level interpretation of the obtained data. Natural environment constitutes a complex system of subtle correlations that need to be perceived as a dynamic medium, in which multi-faceted processes take place.

During last years an interest in the processes of transport and fate of pollutants to the polar regions located distantly from industrial centers, has significantly increased. The current analytical techniques enabling conducting studies prove that the Arctic regions (in the past considered as a pollution free area) have become an area of highly intensive anthropopresion. Svalbard archipelago stands out from the other polar regions due to its specific environmental conditions and geographic location, which results in becoming a reservoir of contamination in this area. Systematic environmental monitoring of arctic regions is extremely important due to an unique opportunity of observing a direct impact of pollution on the ongoing processes in the area of interest. In this way measurement data obtained are a valuable source of information, not only on changes occurring in the Arctic ecosystem, but also on estimated global impact of certain xenobiotics present in the environment. Furthermore, qualitative and quantitative studies on particular chemicals deposited in different regions of the Arctic ecosystem may constitute the basis for undertaking actions aimed at preventing negative effects caused by these pollutants.

This paper is a preliminary attempt to assess the composition of pollutants in two different caldera lakes situated in the Indonesian Archipelago: Batur and Bratan. Both lakes are characterized by largely different physico-chemical regimes; Batur Lake is located in an area that is currently volcanically active, unlike Bratan Lake. The latter is much smaller and shallower than Batur Lake. The concentration of pollutants in the Indonesian equatorial lakes is largely unknown, and the impact of both biological and geothermal processes on their distribution requires attention. This study shows that the concentrations of cations (Na⁺, K⁺, Mg²⁺, Ca²⁺), anions (SO₄²⁻, F⁻, Cl⁻, Br⁻) and trace elements (Li, B, Al, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Cd, Sn, Cs, Ba, Pb, U, Be, Ag, Sb, Tl, Bi) differ greatly between both lakes. Most chemical parameters determined in volcanically influenced Batur Lake were tens to hundreds times higher than in Bratan Lake, and in the case of trace metals, the ratios of the two lakes’ concentrations reached several hundreds. This study also compared the composition and concentration levels of organic compounds in both lakes, such as fatty acids, halocarbons and esters. On the other hand, the content of organic chemicals in the lakes also results from biological activity by phytoplankton, zooplankton and bacteria.