Polycyclic Aromatic Hydrocarbon Composition and Potential Sources for Sediment Samples from the Beaufort and Barents Seas

Abstract

Understanding the sources and pathways of pollutant transport to the Arctic is fundamental to our custody of this sensitive ecosystem. To achieve such an understanding, we need to go beyond a catalog of environmental concentrations. Sediments, which are a final sink for particle-active contaminants, can provide a valuable resource to assess fluxes and sources of contaminants. Here, we interpret PAH distributions from widely distributed Arctic marine sediments both as indicators of anthropogenic contribution and to illuminate transport pathways. We use principal components analysis (PCA) to reveal the potential sources of PAHs and their geochemistry in sediments from the Beaufort and Barents Seas. PCA distinguishes between natural and anthropogenic inputs and supports a direct linkage between anthropogenic emissions and Arctic contamination. In the Beaufort Sea, PAHs and triterpenes reflect strong Mackenzie River-dominated inputs of natural PAHs and petroleum which overwhelm anthropogenic sources. In the Barents Sea, PAH and triterpene concentrations are generally 2−20 times lower than in the Beaufort Sea while the anthropogenic contribution is greater. Samples from the NW Barents Sea and from deep in cores contain natural, predominantly petrogenic material. However, samples from the SE Barents and Novaya Zemlya have received greater amounts of combustion PAHs.