Biochar, Halloysite, and Alginite Improve the Quality of Soil Contaminated with Petroleum Products

Abstract

Investigations into the effective, fast, and economically viable remediation of soils polluted with petroleum-derived products are still relevant. The vegetative pot experiment was conducted at the Didactic-Experimental Garden greenhouse (NE, Poland, 53.759° N, 20.452° E) on loamy sand (LS) and sandy loam (SL) soils. Its main research objective was to assess the effectiveness of biochar (B), halloysite (H) and alginite (A) in the biological regeneration of contaminated soil diesel oil (DO) and petrol (P). The assessment was conducted by determining the magnitude of the adverse impact of these xenobiotics on the growth and development of Zea mays, as well as the activity of seven soil enzymes. The impact of the tested contaminants and sorbents was assessed based on the impact factors (IF) of DO and P, as well as B, H, and A on Zea mays biomass and enzymatic activity of the soil. Soil contamination with petroleum-derived products disrupted the growth and development of Zea mays. DO had a stronger inhibitory effect on plant growth compared to P. Zea mays cultivated in LS, which was less resistant to the effects of these contaminants compared to that cultivated in SL. The impact of DO and P on enzyme activity depended on the soil texture. DO stimulated enzyme activity in LS and SL, while P only did so in LS. All remediation substances, and biochar in particular, led to an increase in plant biomass in the DO-contaminated soils. Both biochar, halloysite and alginite also improved the biochemical quality index (BA) of SL and LS. Despite the unquestionable remediation potential of the analyzed sorbents, their highest efficacy can only be achieved by their application on soils with physicochemical properties corresponding to their characteristics, which is a valuable guideline for further research.