Domuschy S. Factors and geography of soil pollution in the Odesa urban and suburban areas.

The modern nature of the development of human civilisation leads to significant negative impacts on the ecological state of the environment. Both at present and in the near future, the negative role of humans in the biosphere cannot be completely neutralised, which requires scientific justification of the permissible limits of anthropogenic impact on natural complexes in general and soil cover in particular. Soils are an integral component of the environment, being an indispensable means of production in agriculture and performing certain phytosanitary functions in the urban environment. Odesa is a large industrial and resort city with the following facilities the largest seaport, machine­building and metalworking enterprises, chemical and petrochemical, food and automotive industries and developed transport links. Large technogenic load on the environment, uneven territorial concentration of production, high content of pollutants in emissions from motor vehicles leads to pollution of the city's soils and and deterioration of their environmental properties. Particularly dangerous is the pollution of agricultural soil within the area of influence of motor vehicles and urban soils with heavy metals. The aim of the study is to assess the level of soil and ground cover pollution in the city of Odesa and the suburban area under the conditions of modern transport and industrial load. The natural soils of urban and suburban areas are southern black soils. In the city, natural soils are found only within certain park areas and on the territory of the Botanical Garden. The city's anthropogenic soils are marked by significant diversity and heterogeneity of their formation (on cultural layers, natural buried soils, layers of construction waste, etc.) The vegetation cover of the city's lawns is poor, represented by 2­10 types. In the top ten plants that are most important in the formation of lawns are dominated by weeds and cereal grasses that help to sod the soil surface. The surface of urban soils are characterised by varying degrees of recreational load (weak, medium or absent), and projected vegetation cover from 0 to 100% (on artificially greened lawns). Soils are usually cluttered with inclusions of household and construc-tion waste. In terms of granulometric composition, the city's soils are predominantly light to medium loamy; black soils in the southern suburban areas are characterised by a predominantly heavy loamy granulometric composition. The reaction of the environ-ment (pH of the soil solution) of the upper humus horizons of urban soils varies widely: from alkaline to strongly alkaline (7,37­ 9,14) with a significant shift to the alkaline side, which is a general trend of urbanised soils. The highest pH values of soil solution are found in soils within of significant impact of road transport and indust-rial enterprises. The increased alkalinity of some urban soils is associa-ted with an increased content of absorbed sodium in the soil absorp-tion complex, which is the result of anthropogenic impact. The content of exchangeable calcium, magnesium and sodium is highly variability and varies accordingly: exchangeable calcium content ­ from 0,16 to 8,72 mmol/100 g of soil; magnesium ­ from 0,02 to 0,76 mmol/100 g of soil, sodium – 0,01­53,00 mmol/100 g of soil. Black soils in the southern suburban zone have a neutral, slightly alkaline reaction of the environ-ment; on the roadside (within the influence of motor vehicles) ­ alkaline. Accordingly, the average content of exchangeable calcium, magnesium and sodium outside the influence of road transport is 0, 49 mmol/100 g of soil, 0,15 mmol/100 g of soil, 0,09 mmol/100 g of soil and on the roadside 0,43 mmol/100 g of soil, 0,11 mmol/100 g of soil, 0,22 mmol/100 g of soil.