Assessment of Lithium Ecotoxicity in Soils with Contrasting Properties

The aim of the work is to evaluate the ecotoxicity of lithium in soils with contrasting properties: Haplic Chernozem, Eutric Cambisol, and Eutric Arenosol. Model experiments on soil contamination with lithium were carried out with different lithium concentrations: 15, 30, 50, 100, 125, 250, and 500 mg/kg. After 10, 30, and 90 days of the experiment, biological indicators of the soil condition were studied: catalase and dehydrogenases activity, the total population of bacteria, the number of bacteria of Azotobacter genus, and the length of radish roots and shoots. Contamination of soils with lithium in concentrations of 50, 100, 125, 250, and 500 mg/kg contributes to a significant decrease in all biological parameters at all periods of the experiment. In Haplic Chernozem and Eutric Cambisol, a 15 mg/kg dose of lithium hydroxide (LiOH) causes the effect of hormesis. Lithium had the greatest negative effect on the 10th day from the beginning of the experiment, and by the 90th day all soils tend to restore their biological parameters to those characteristic of uncontaminated soils. Haplic Chernozem showed the greatest resistance of its biological indicators to lithium contamination compared to Eutric Cambisol and Eutric Arenosol, which is due to the genetic properties of soils (granulometric composition, pH, and humus content). The results of the study can be used in predicting risks of lithium contamination of soils and in developing the environmental standards for lithium content in soils.