Assessment of heavy metals content in podzolic soil for various granulometric composition when applying activated sludge as the basis for nanofertilizer (the pulp-and-paper industry waste)

Introduction. Activated sludge is one of thepulp-and-paper industry waste types. Within the framework of the rational natural resources' utilizationand the waste recycling, due to its composition, activated sludge could be subjected to certain technological solutions for the production of nanofertilizers, since it has been previously the basis for making of various soils and biological products. However,occasionally the composition of activated sludge may contain different toxic compounds, heavy metals, and their impact on soil fertility and plants vital state is profound. Thus, the purpose of our research is to study the effect of the activated sludge introductionas a basis for nanofertilizers on the heavy metals contentin podzolic soils of various granulometric composition in agricultural exploitation. Methods and materials. Research was conducted under the conditions of dummy experimentin vegetation vessels. We have used podzolic soils of various granulometric composition (clayey, loamy, sandy) and pulp-and-paper industry waste - activated sludge in concentrations of 1; 2.5; 5 and 10% of the dried soil weight. Determination of the heavy metals gross content has been carried out by the atomic absorption method with measurement on the AA-7000 spectrophotometer (Shi-madzu, Japan); mobile fraction of heavy metalsdetermination (подвижныеформы) - utilizing acetate-ammonium buffer solution by inductively coupled plasma mass spectrometry methodology. Results and discussion. The paper presents the results of the research on mobileand gross forms of heavy metals in podzolic soil of various granulometric composition when applying activated sludge as the basis of organic nanofertilizer under the dummyexperiment. Conclusion. It was shown that the content of mobile and gross forms of the studied metals (Fe, Mn, Cu, Zn, Ti, Al, Ni, Co, Cr, Cd and Mo) were within the health-based exposure limits, with the exception of Cd gross form, where the maximum excess was 2.5 MAC (maximum allowable concentration).