Indication of the ecological status of urban soils based on some chemical and microbiological indicators (on the example of Astrakhan)

The aim of the research was to determine the ecological status of soils in the industrial, residential and recreational areas of the Astrakhan city. As a result, biological and enzymatic activity of the studied soil samples was studied. Soils in the territory of LUKOIL-NVNP oil depot No. 5 showed low biological activity. Low enzymatic activity was shown by soils of the residential area. Using the obtained results, we calculated an integral indicator of the biological state of the studied soils based on the complex of 15 microbiological and biochemical parameters. The maximum values of the integral indicator of biological state (IIBS) of soil were marked for soils of recreational area, minimal - for soils of industrial area (tank farm No. 5 OOO «LUKOIL-NWNP»). They were 81,2% and 26,2 %, respectively. For data processing and analysis we used clustering based on a set of chemical and microbiological indicators. As a result, 3 clusters were formed. Minimum differences in chemical and microbiological parameters were established for soils selected in the territory of LUKOIL-NVNP oil depot No. 5. The second cluster was formed by the soils of the residential area and Confectionary plant «Karon», the third - by the soils selected in the recreational area of the city. It was also established that microbiological indicators were most applicable to determine the ecological state of urban soils in the industrial and residential areas compared to biochemical ones. The obtained results show that the ecological status of soils in the industrial, residential zone and V.I. Lenin Park can be characterized as highly dangerous by the values of integral indicators.