Polycyclic aromatic hydrocarbon level, origin and ecological risk assessment in sediments with different grain size properties in Peter the Great Bay (the Sea of Japan).

The study presents the first data on PAH levels and associated environmental risks in the sediments of Peter the Great Bay, the largest bay in the northern Sea of Japan. The total 14PAH concentrations in the sediment ranged from 27 to 2432 ng/g, with an average value of 553 ng/g. The isomer concentration ratios and Principal Component Analysis revealed that the PAHs were mainly derived from coal combustion. The spatial PAH distribution was mainly dictated by anthropogenic load (shipping and urban runoff) and deposition regime exhibit enhanced capacity for PAH retention and burial in the inner shelf. Fine fractions (silt and clay) and organic carbon were significantly positively correlated with the total PAH content. Comparisons with sediment quality guidelines (ERL/ERM, TEL/PEL) showed low and possible ecological risk in the location under the influence of the Tumen River runoff and the urban coastal area. However, the guidelines for total OC-normalized PAHs determined that the sediments are of low risk for benthic animals. The results of toxic and mutagenic equivalence quotients (TEQ and MEQ) revealed a hotspot of carcinogenic and mutagenic PAH activity in the sediments of Port Vladivostok outer harbor. According to TEQ and MEQ values, fine-grained sediments in Peter the Great Bay demonstrated 3-4 times higher carcinogenic and mutagenic activity compared to coarse sandy sediments.