Evaluation of polycyclic aromatic hydrocarbon pollution levels and ecological risk in the estuarine ecosystems of western Peter the Great Bay (the Sea of Japan)

The one-time study examined the concentrations of polycyclic aromatic hydrocarbons (PAHs) in the estuarine regions of three rivers emptying into Peter the Great Bay (Sea of Japan), with a concomitant evaluation of the attendant environmental hazards posed by the biological activity of these compounds. The total PAH content was low, except for the river section of the Shmidtovka Estuary, where elevated PAH concentrations were observed. The compositional PAH profile exhibited similarity between the Amba and Tumen rivers, whereas the Shmidtovka River displayed a distinctive profile characterized by a preponderance of 3- and 5-6-ring compounds. An analysis of diagnostic isomer ratios revealed the presence of PAHs originating from both petrogenic and pyrogenic sources in the estuaries. Furthermore, the toxicity and mutagenicity indices (TEQ and MEQ) were found to be within standardized limits for benzopyrene, although the freshwater zone of the Shmidtovka River Estuary exceeded the benchmark value of 5 ng/L, potentially inducing carcinogenic and mutagenic effects in aquatic organisms inhabiting the riverine environment.