Soils from an iron and steel scrap storage yard remediated with aided phytostabilization

Areas degraded by industrial activity demonstrate unfavorable chemical and physical conditions, including a high concentration of trace elements (TEs), which reduce the growth and development of appropriate plant cover. For the above reasons, in recent years, the demand for the development of natural and effective technologies for removing particularly hazardous compounds such as TEs from the environment has been growing. Because aided phytostabilization is a relatively new technology, examination of new additions immobilizing TEs in combination with an appropriately selected species plan poses a challenge in environmental protection and engineering. The novelty of this study is in the assessment of the usefulness of previously not applied soil amendments in processes of TEs immobilization in contaminated soils. This study presents the results of a vegetation experiment using a mix of grasses and rarely used mineral soil amendments (halloysite, diatomite, dolomite) for aided phytostabilization of soil originating from an area affected by industrial activity and characterized by high TEs concentrations. Additionally, the degree of phytotoxicity of the examined soils was determined. The greatest above-ground biomass was observed when diatomite, dolomite, and halloysite were added to the soil. The concentrations of the analyzed TEs in test plants were higher in roots than in the above-ground parts. This indicates that mineral amendments affected soil properties promoting TEs precipitation and decreasing TEs bioavailability. The highest increase in soil pH was observed after the application of dolomite to the soil. The average contents of Pb, Ni, Cu, and Cr in soil demonstrated the highest reduction after diatomite and halloysite application. The conducted research confirms the possibility of applying the examined soil additives to support phytostabilization of alkaline soil highly contaminated with TEs.