Surface distribution of dissolved polycyclic aromatic hydrocarbons along northeastern Japan Sea and Okhotsk Sea

Abstract

Average of Σ14DPAHs concentration was 3.64 ng L^-1 (1.67-5.15 ng L^-1) in 2017 and 3.97 ng L^-1 (1.98-6.48 ng L^-1) in 2019. In 2017, higher DPAHs concentrations were observed at higher latitudes, while in 2019 the trend was reversed. Salinity and temperature profiles indicates an eastward surface mixing of Liman Current water (salinity 32.5-33.0, temp. ＜16℃) within the subarctic gyre in 2017 and a purer transport of Tsushima Warm Current (salinity 33.7-34.5, temp. >17℃) in 2019. Such results were contrasted with the DREAMS model. From the diagnostic ratios [Flu] / [Flu + Pyr] (0.49-0.69) and [BaA] / [BaA + Chr] (0.33-1.0), sources of DPAHs were inferred to be majorly pyrolytic at all points. In conclusion, the DPAHs distribution along northeastern Japan Sea is related to both surface currents.