Polycyclic aromatic hydrocarbons in ocean sediments from the North Pacific to the Arctic Ocean

Eighteen polycyclic aromatic hydrocarbons (PAHs) were measured in surficial sediments along a marine transect from the North Pacific into the Arctic Ocean. The highest average Σ₁₈PAHs concentrations were observed along the continental slope of the Canada Basin in the Arctic (68.3 ± 8.5 ng g^-1 dw), followed by sediments in the Chukchi Sea shelf (49.7 ± 21.2 ng g^-1 dw) and Bering Sea (39.5 ± 11.3 ng g^-1 dw), while the Bering Strait (16.8 ± 7.1 ng g^-1 dw) and Central Arctic Ocean sediments (13.1 ± 9.6 ng g^-1 dw) had relatively lower average concentrations. The use of principal components analysis with multiple linear regression (PCA/MLR) indicated that on average oil related or petrogenic sources contributed ∼42% of the measured PAHs in the sediments and marked by higher concentrations of two methylnaphthalenes over the non-alkylated parent PAH, naphthalene. Wood and coal combustion contributed ∼32%, and high temperature pyrogenic sources contributing ∼26%. Petrogenic sources, such as oil seeps, allochthonous coal and coastally eroded material such as terrigenous sediments particularly affected the Chukchi Sea shelf and slope of the Canada Basin, while biomass and coal combustion sources appeared to have greater influence in the central Arctic Ocean, possibly due to the effects of episodic summertime forest fires.