The Role of Precipitation in the Process of PAHs Deposition in the Arctic Environment at the Background of Climate Change

The atmosphere is one of the basic elements of the environment into which the increasing amount of particulate matter, gases, aerosols from both natural and anthropogenic sources are released. The broad spectrum of contaminants is transferred to the remote areas including virgin territories, where there are no significant sources of pollutants emission, by the atmosphere, ocean currents, ice floes and living organisms. Volcanic eruptions are the most intense natural phenomenon associated with the emission of tons of pollutants to the atmosphere. The huge scale of this phenomenon, caused by eruptions of some volcanoes, poses a real threat especially to these parts of Earth which are sensitive to environmental changes. Moreover, intense eruptions characterised by the emission of dust and gases into the upper stratosphere may lead not only to the contamination of large areas of Earth, but also to the change of clouds properties including polar stratospheric clouds, the greenhouse effect creation, climate change and their consequences. Contaminants in the atmosphere are subject to a variety of processes such as convection, diffusion, chemical and photochemical reactions. Polluted, after eruption-clouds may be transported over long distances becoming a serious problem. Depending on the size of the explosion and the prevailing climate and meteorological conditions during the eruption, pollutants are moved into the individual layers of the stratosphere. Impurities are carried in the direction of winds and air mass circulation thus they are able to remain in the atmosphere for a long period of time and may be transported over long distances. Through the sedimentation process or wet deposition of particles of the individual components, pollutants are submitted to the ecosystems. Precipitation particles elute the impurities contained in the clouds and during the fall, they also elute some of the substances placed below the clouds base. The premise for undertaking research on pollutants migration in the polar environment is the Arctic that plays a huge role in nature, particularly in the formation of the solar radiation balance, Earth radiation, heat balance of the atmosphere and Earth surface, as well as in the development of the weather and climate during the rapid global changes. Furthermore, substances emitted to the atmosphere by volcanic eruptions contribute directly (toxic impact of chemical compounds and their mixtures) and indirectly (induction processes of glaciers melting and pollutants release from the permafrost) to the soil and water contamination. The main purpose of this study is to confirm the scientific hypothesis on the significant impact of the volcanic eruptions and related pollutants emissions into the atmosphere, on the susceptible to changes Arctic ecosystems. In this study, particular attention has been paid to the compounds belonging to the group of polycyclic aromatic hydrocarbons (PAHs), due to documented harmful effects on the functioning of the Arctic flora and fauna species. The results of 16 different PAHs compounds determined in samples from lake and atmospheric precipitation from the Arctic catchment (Hornsund Fjord) were presented. The water samples were collected every summer from 2010 to 2014. One of the main natural sources of PAHs emission are volcanic eruptions. Whereas, one of the principal PAHs pathways to the aquatic environment is the atmosphere (as a result of dry deposition process and atmospheric precipitation), as well as leaching from contaminated soils. PAHs are a threat to the entire Arctic ecosystem. They influence indirectly its different elements, for instance by metabolic transformation and as a result of biomagnification. The authors would like to thank the staff of the Polish Polar Station at Hornsund for the opportunity to carry out sampling and for their assistance with this work. Thanks the National Science Centre for research funding grant no. 2013/09/N/ST10/04191.