POPs distribution in coastal permafrost soils at Komakuk Beach (Yukon, CA)

The extensive work in AMAP on Arctic contamination by Persistent Organic Pollutants (POPs) illustrates the strong state of knowledge and data on contaminants in biota and water, but also highlights a stark data gap regarding contaminants in Arctic soils, particularly below the permafrost table. Here, we describe the work carried out on analyses and scaling of contaminants. A key aspect for being able to deliver geospatial databases is identifying which landscape properties we can use to scale the measured contaminant levels. Soils in the Canadian study area at Komakuk Beach (Yukon, CA) have been sampled and analysed for hexachlorobenzene (HCB), 54 polychlorinated biphenyl congeners (PCBs) and 22 individual polycyclic aromatic hydrocarbons (PAHs) in 89 active layer and permafrost core samples. The concentrations have been determined by using Thermo Scientific Dionex ASE 350 and Trace 1310 GC coupled with TSQ9000 TQMS, Thermo Scientific, at CNR-ISP Venice, Italy. The statistical parameters of data on HCB concentrations describe its scarce presence, with limited occurrences linked to the organic rich soil horizons. Overall, Σ54PCBs in soils collected in the catchment area were in the range from 0 to 5.33 pg/g. Both the content of individual PAHs and their total concentration vary widely from 0 to 121ng/g. The contribution of individual PAHs to the total amount is not the same and depends on the concentration of heavy 5–6-nuclear polyarenes and mainly 6-nuclear benzo[ghi]perylene. Our results show that the vertical distribution patterns of light 2–4-nuclear and heavy 5–6-nuclear PAHs are differentiated. Every class of OC is present in the deeper permafrost core portions only in High Centre Polygon (HCP) landform class, highlighting the role of hydrology and percolation in the contaminant distribution in permafrost soils and how these variables are enhanced in (semi-)degraded permafrost landforms. The model equations have been applied on the carbon content prediction maps for each study area, to export a first attempt of upscaling feasible for small coastal catchments in polygonal tundra environment. Contaminant concentrations ranges were calculated for different depth from 0 to 1 meter below the ground, following the carbon content prediction maps from Wagner et al. (in prep.).