Assessment of heavy metal pollution levels in soils of specific areas of the Odesa industrial-urban agglomeration

Abstract

Unlike the more dynamic air basin and surface waters, where active self-purification processses occur, soil virtually lacks this capacity. The cleansing processes in soil are very slow, only through leaching, plant uptake, and water erosion, which poses an environmental hazard in urbanized areas over long periods. In the process of intensive urbanization, the soil cover has been influenced by many anthropogenic factors, resulting in changes to its physical and chemical properties and an increase in heavy metal concentrations. An analysis of previous research results shows that the most contaminated soils with specific heavy metals are found in industrial zones and areas adjacent to high-traffic roads. In contrast to these technogenically stressed areas, attention is drawn to park and square zones, where elevated background concentrations of lead and zinc have been recorded, whereas copper content in all areas was identified to be below background levels. However, the range of calculated geoaccumulation index values for these heavy metals corresponds to a low-to-moderate level of soil contamination which varies according to the distance from sources of technogenic pollution. According experimental results by biosensor bioluminescent analysis of soils from certain parks and squares of the Odesa agglomeration, no significant inhibition of luminescence levels of microbial cells-the basis of the sensor elements-was observed. This indicates the absence of substances which have toxic effect to soil microorganisms.