CURRENT ECOLOGICAL STATE OF THE SEA WATERS NEAR THE NORTH-WESTERN COAST OF THE CRIMEA

Abstract

In the Western Crimea coastal marine waters in June–July 2023 the pollution by petroleum hydrocarbons (TPHs), anionic detergents (APAV) and trace elements (heavy metals) was studied. There was no significant change in hydrological indicators, including the water salinity varied in range 17.27–18.71 ‰, which could have been the result of a recent breakthrough of the dam of the Kakhovsky reservoir. The results showed the predominant importance of petroleum hydrocarbons in assessing the quality of marine waters according the standard calculation of Index of Water Pollution (IWP). The concentration of TPHs was equal to or exceeded the established normative MAC = 0.05 mg/dm³ in 87 % of the samples taken. Two maxima (0.36 and 0.50 mg/dm³) were recorded in the Karkinite Bay apart from coast and reached 7–10 MAC. Near coast here the values were rather high also (0.08–0.09 mg/dm³). The content of of detergents and heavy metals was quite low and did not reach the corresponded MAC. The oxygen regime was generally within normal limits throughout the studied marine water area. The exception was only the top of the Karkinite Bay, where its deficit of dissolved oxygen reached 27 %. In the colder waters near the bottom the concentrations of oxygen increased. The contribution of each studied pollutants into the level of IWP was assessed. The difference in the hydrochemical state of the Karkinite and Kalamita Bays of the Western Crimea is shown. According to the magnitude of the pollution index, the waters of the Kalamita Bay were characterized as “clean” while the Karkinite Bay as “moderately polluted”.