Local contributions and climate change effects on organochlorine pesticide levels in soil and sediments in Svalbard

Abstract

The Arctic region, including Svalbard, faces unique environmental challenges from the presence and persistence of organochlorine pesticides (OCPs), pollutants known for their long-range atmospheric transport and potential local sources. In Svalbard, the melting of sea ice and glaciers due to climate change may release OCPs trapped over decades, while human activities in the area could contribute additional local contamination. This study aimed to identify and quantify different sources of OCPs in soil and marine sediments at Svalbard. Samples were collected from Kongsfjorden, Rijpfjorden, and in Ny-Ålesund. The concentrations of 23 OCPs in sediments sampled were in the range of 0.36–0.90 ng/g, which were lower than those in the soils from Ny-Ålesund (0.28 ng/g to 3.6 ng/g). The highest OCP levels were detected at locations near the research station in Ny-Ålesund, where local contamination from research activities, mining, and dumpsites could occur. Hexachlorobenzene (HCB) were the most prominent compound, followed by various DDTs and HCHs. Dignostic ratios and the Positive Matrix Factorization (PMF) model were employed to determine the primary sources of OCPs. The results from modeling showed that historically used pollutants were the primary contributor, accounting for 90% of OCPs present, while recently input OCPs were a minor contributor. However, newly input pollutants significantly contributed to HCHs (43%). It is suggested that the contribution of legacy OCPs mainly comes from the melting of sea ice and glaciers. This was especially true for Rijpfjorden (95%), while it was also significant for Kongsfjorden (55%). The local contamination and fresh inputs played a substantial role in the area near the research station in Ny-Ålesund. The study emphasizes the importance of secondly source, especially the role of melting sea ice and glaciers as well as local contaminations as sources of OCPs in Svalbard's marine sediment, which highlight the urgent need to address the impact of climate change on the Arctic environment.