Features of copper accumulation in the soils of different functional areas of Novokuybyshevsk

The vegetation of the Samara Region is characterized by a relatively high content of copper. This biogeochemical feature is typical for natural and technogenic transformed ecosystems of the region. Copper is included in the group of elements of the 2nd hazard class. At certain concentrations it is necessary for the normal functioning of all organisms, but with increasing concentrations in the environment or in food it shows toxicity. The technogenic sources of copper include metalworking and machine-building enterprises, fertilizers, road and rail transport, wastewater, products of incomplete fuel combustion and refining characteristic of the Samara Region. The peculiarities of copper accumulation and distribution in soils of urban areas of the region are insufficiently studied. Previously, such studies were carried out only in certain areas of Samara. The paper analyzes in detail the level of technogenic copper pollution of the soil cover in Novokuybyshevsk. Ecological and geochemical studies in Novokuybyshevsk were carried out for 3 years (2016-2018) on 7 stationary test plots in its different functional areas and on 1 background test plot. The objects of research were soil samples taken from the upper humus horizon (layer 0-10 cm). The quantitative content of copper in soil samples was determined by the method of inversion voltammetry. A comparative analysis revealed territories of Novokuybyshevsk with relatively high, medium and low levels of copper in the soil. The first group included the Park «Dubki» in its elevated part, the old residential area on Kirov Street, the roadside area at the intersection of Pobeda Avenue and Dzerzhinsky Street (93,3-90,7 mg/kg). The second group with an average copper content (71,0-73,3 mg/kg) included the square «Elochki» and a new residential area on Ostrovsky Street. The third group with a relatively low copper content (38,3-54,7 mg/kg) included three sample areas: the lowland part of the Park «Dubki», the industrial zone and the background area. The concentration of copper in the soils of all studied functional zones in Novokuybyshevsk has not reached the level of approximate permissible concentration (APC), but more than the clark of the world soils and the background indicators. The downward trend in the concentration of copper in the soils of most of the studied functional zones of Novokuybyshevsk in 2018 compared with 2016 and 2017 at the relatively low level of copper content in soils of the industrial area of the city allows to exclude oil refineries from the list of its major anthropogenic sources.