ASSESSMENT OF HEAVY METALS CONTENT AND ENVIRONMENTAL RISK IN URBAN SOILS

Abstract

The relevance of the study is caused by the need to reveal the features of accumulation of heavy metals in the soils of the urban landscapes of Vladivostok and Ussuriysk and to establish the value of the potential environmental risk. The main aim of the work is to assess the geochemical state of soils in various functional zones of urban landscapes using several pollution indices. Methods. The total content of trace elements in soils was determined by x-ray fluorescence spectroscopy using an EDX-800HS (Shimadzu) spectrometer. Results. Chromium, copper, zinc and lead accumulate to the greatest extent in the upper soil horizons of urban landscapes under the influence of a strong technogenic load. The content of vanadium, cobalt, and nickel is comparable to or lower than clark. The average and maximum values of complex pollution coefficients PLI and NPI indicate the degradation of the surface layer of urban soils and a strong degree of heavy metal pollution. The value of the potential environmental risk index varies from small to medium. The soil pollution level in various functional zones increases in the following series: recreational zone<zone of multi-storey buildings<transport and residential zone<zone of low-rise buildings, while the level of pollution varies from the assessment of «clean» to the assessment of «highly polluted». Weak accumulation of chromium, zinc and copper was detected in some soils of recreational zones. A noticeable increase in the content of various heavy metals was found in the soils of the Vladivostok the multi-storey development zone, increase in the copper content was noted in Ussuriysk. Chromium, copper, lead and zinc are accumulated in the soils of transport and residential zone and low-rise buildings zone with varying degrees of intensity. Higher values of both individual (Igeo, EF, PI) and complex pollution indicators (NPI, PLI, PERI) were found in the soils of Vladivostok.

Keywords

• urban landscape soils
• pollutants
• heavy metals
• environmental risk
• pollution index