Comparison of the Effectiveness of Micro- and Nanoparticles of Zero-Valent Iron in the Detoxification of Technogenic Polluted Soil

Abstract

We studied the safety of sorbents based on zerovalent iron in the form of micro- and nanoparticles and their detoxifying activity in peat eutrophic soil (Eutric Histosol) polluted by emissions from a copper-nickel (Cu/Ni) plant (Kola Peninsula, Russia). Iron nanoparticles, as well as iron microparticles at a dose of 2%, turned out to be non-toxic according to the results of three standard bioassays based on the reactions of test organisms of different taxonomic affiliation. Toxicity was assessed by the change in the length of the roots of seedlings of plants Sinapis alba L. in uncontaminated peat, by the survival of Ceriodaphnia affinis Lilljeborg and the protozoan Parameciun caudatum Ehrenberg in water extracts of the samples. Fe-containing preparations significantly reduced the ecotoxicity of the soil due to the extremely high content of copper (6877 mg/kg) and nickel (2580 mg/kg). Differences in the remediating ability of the preparations were revealed. According to the results of soil phytotesting, iron nanoparticles significantly outperformed the detoxifying effect of microparticles (iron powder). When analyzing the water extract, the superiority of nanoparticles in reducing soil toxicity was not found. The dependence of the assessment of the detoxifying ability of zerovalent iron nanoparticles on soil properties and the plant species used in phytotesting is discussed.