Monitoring of contamination of the north-western shelf of the Black Sea in the zone of exploration of the promising gas deposits

The following tasks were carried out: 1) analysis of the level of contamination in the background areas of the north-western shelf of the Black Sea (Ukraine) beyond explorated deposits of gas and gas condensate; 2) complex ecological studies of the ecosystem state on the north-western shelf with regard of predominant shifts of water masses; 3) assessment of the level of impact of the objects of the industrial enterprise 'Chernomorneftegas' on the water environment and bottom sediments in the areas of location of marine stationary platforms (MSP). Monitoring of contamination of water and bottom sediments of the area under study was carried out by following indices: heavy metals (mercury, copper, lead, cadmium, chromium) and oil components (volatile and non-volatile carbohydrates, resins and asphaltens). Bottom sediments of the north-western shelf of the Black Sea are most polluted with lead, concentrations of which exceeded geochemical background all over there. Negative impact of drilling on the components of the ecosystem reveal itself to the greatest extent directly near the wells or southward that agree well with data on distribution of bottom biocenoses. In the zone of location of marine stationary platforms on the north-western shelf increased content (in comparison with background values) of oil components was observed both in the surface and near-bottom layers with predominance of non-volatile carbohydrates in the fractional composition that is a feature of secondary contamination. Summary content of oil products in bottom sediments of Odessa Bay and adjacent area of the shelf, near-Danube region is compatible with values characteristic with most polluted stations in the zone of location of MSP. In the component composition, resins and asphaltens are prevalent (up to 1.94 mg/g of dry matter). In bottom sediments of the zone of location of MSP summary content of oil products varies in the wide range, from 0.063 to 2.849 mg/g of dry matter.