Railway Urbanozems: Interrelation of Physicochemical and Integral Environmental Indicators

Abstract

Urbanozems with typical pollution are formed along railways: heavy metals (HM), oil products, anthropogenic organic matter. Depending on the natural zone and intensity of the leaching regime, the accumulated pollution can have a different effect on the integral environmental indicators of soils – the toxicity and enzymatic activity. The aim of the work was to determine the influence of the railway on the physicochemical characteristics of adjacent urbanozems that are formed in the southern taiga zone and to find out the interrelation of these indicators with the toxicity and catalase activity of the soil. Samples of urbanozems were taken from the surface layer of 0-10 cm at the distance of 50 m west and east of the railway and at the distance of 100, 500, 1000 m of it (east). The pH, content of organic matter, humus, ammonium nitrogen, mobile forms of HM, mortality for Daphnia magna Straus, influence on bioluminescence of Escherichia coli Migula, and the catalase activity were determined in the samples. It was shown that the levels of toxicity and the activity of catalase are strongly related to the distance from the railway: Pearson’s coefficients (r) were -0.53 (D. magna), -0.69 (E. coli), 0.95 (catalase). However, the interrelation between the total pollution index (TPI) of metals and integral indicators is lower: r=0.50 for the pair “D. magna – TPI”, r=0.42 for “E. coli – TPI”, r=0.19 for “catalase – TPI”. Consequently, the reactions of living organisms and the activity of catalase were formed in response to a combination of pollutants, not to one group of compounds.