The polycyclic aromatic hydrocarbons in the water of the Black Sea studied during the research cruise no. 114 aboard the r/v “Professor Vodyanitsky” in 2020

Abstract

The content and composition of polycyclic aromatic hydrocarbons have been studied in the water column (surface layer, thermocline layer, at a depth of 500 m and the bottom layer) of the deep-water areas of the Black Sea near the Crimean Peninsula and the Caucasian coast, and the results are presented. The identified PAHs included naphthalene, 2-methylnaphthalene, phenanthrene, anthracene, fluoranthene, pyrene, triphenylene, chrysene, benz (b) fluoranthene, benz(k)fluoranthene, benz(a)pyrene, dibenz(a,h)anthracene, benzo(g,h,i)perylene. The concentrations of the total PAHs detected near the capes Sarych and Chauda were the highest, 532 and 593 ng/L, respectively. The distribution of PAHs over the horizons did not have a clear pattern. The composition of PAHs was dominated by 2-nuclear compounds, namely, naphthalene and 2-methylnaphthalene, their share on average accounted for 63 % of the total of the PAHs identified. The most dangerous nuclear PAHs containing 5 and 6 aromatic rings (benzo(b)fluoranthene, benz(k)fluoranthene, benzo(a)pyrene, dibenz(a,h)anthracene) accounted for less than 0.5 % in all the analyzed water samples. According to the calculated indices of technogenicity and pyrogenicity, PAHs of naphthydogenic origin predominated in almost all analyzed water samples. PAHs of technogenic oil origin prevailed in the water samples taken in the zone of shipping lanes to the port of Novorossiysk.