ASSESSMENT OF TOXICITY AND POLLUTION OF BOTTOM SEDIMENTS IN THE NORTHWESTERN PART OF THE BLACK SEA WITH HEAVY METALS

Abstract

The northwestern shelf is the most polluted regions of Black sea. The aim of the work was to compare the levels of bottom sediment’s toxicity and pollution with heavy metals (As, Cd, Hg, Pb, Zn, Cu, Ni, Co, Cr) in the Odesa Region and seaside of Kylyia branch of the Danube (further: Seaside of the Danube). In this article we used the methodology of EU Frame Work Directive. The criterion for the quality of bottom sediments was the Target value (TV) indicator, developed in the Netherlands. Acute toxicity of bottom sediments extract on distilled water was determined using laboratory cultures of Hyalea azteca (Saussure, 1858). According of the result of biotesting, in the Odesa Region the bottom sediments of quality class 3 (moderate) were formed under the inflence of bilge waters from the roadstead of ships, trans fer of polluted water from Odesa Sea Commercial Port area and Treatment plant “Northern”. The rest of the bottom sediments of the polygon were assigned to a quality class 2 (good) and a quality class 1 (excellent). At the Seaside of the Danube the bottom sediments of quality class 3 (moderate) were formed by carrying the polluted river waters out of Bystroie (Novostambulskoie) and Starostambulskoie branches. The bottom sediments of the rest of the polygon were assigned to quality class 2 (good) and quality class 1 (excellent). The average content of mercury in the bottom sediments was 0.21∙g–1on dry mass (0.7 TV) in the Odesa Region, and 2.26 g–1 on dry mass (7.53 TV) at the Seaside of the Danube. The greatest impact to pollution of bottom sediments was made by mercury – 11.77 TV, copper 2.09 TV and cobalt – 1.50 TV in the Odesa Region, and mercury – 118.23 TV, nickel – 7.15 TV and cobalt – 4.33 TV at the Seaside of the Danube.