Effect of Heavy Metals on the Enzymatic Activity of Haplic Chernozem under Model Experimental Conditions

Abstract

The biological activity of soils is an essential parameter of their ecological status. The anthropogenic Heavy Metals (HMs) disturb the normal functioning of soil biota and, hence, the entire soil system. The aim of this work was to estimate the toxicity of loosely bound HM compounds in Haplic Chernozem using parameters of cellulose-degrading and urease activities. Contamination of Haplic Chernozem with Zn, Cd, Cu and Pb enlarged the group of mobile (loosely bound to soil) metal compounds, which includes exchangeable, complexed and specifically sorbed compounds of HMs. The increase of mobile HM forms content in soil inhibited the cellulose-degrading and urease activities after 30 days of the input of metal into the soil. A decrease in the toxic effect of metals on the studied parameters mainly occurred in the next 30 days. It was found that all HM forms similarly affected biological activity parameters. During two months from the moment of soil contamination with HMs, their toxic effect on cellulose-degrading and urease activities decreased. According to the degree of inhibition of biological activity in Haplic Chernozem, the studied metals formed the following series: Cd >Pb > Zn > Cu.

Assessment of the Ecotoxicity of Pollution by Potentially Toxic Elements by Biological Indicators of Haplic Chernozem of Southern Russia (Rostov region)

“…In soils with a lighter granulometric composition, less organic matter, and more acidic, the ecotoxicity of most pollutants will be even higher (Kolesnikov et al, 2020 , 2021 ; Guney et al, 2020 ; Minnikova et al, 2017 ). According to the degree of inhibition of biological activity in Haplic Chernozem, the studied metals formed the following series: Cd > Pb > Zn > Cu (Gromakova et al, 2017 ). The physicochemical properties of soils and technogenic load affect their biological activity.…”

Current State of Haplic Chernozems in Specially Protected Natural Areas of the Steppe Zone

“…Haplic Chernozems are characterized by specific distributions of free carbonates in the form of carbonate mold along with common carbonate neoformations (beloglazka and veins) (Bezuglova and Yudina, 2006;Bezuglova and Tischenko, 2012;Gromakova et al, 2017;Minkina et al, 2008;2010). Haplic Chernozems are frequently called micellar-calcareous chernozems.…”

The Influence of Potentially Toxic Elements on Soil Biological and Chemical Properties

“…Gromakova et al [74] during their work reported that the increase of mobile potentially toxic element forms content in soil inhibited the cellulose-degrading and urease activities after 30 days of the input of metal into the soil. The inhibition of biological activity of the studied metals formed the following series: Cd > Pb > Zn > Cu.…”