The Potential of Hydroxyapatite for the Remediation of Lead-Contaminated Territories: A Case Study of Soils in Primorsky Krai

Finding ways to enhance the resilience of soil ecosystems in the context of heavy metal contamination remains an important and urgent challenge. This work is devoted to assessing the impact of the soil composition in Primorsky Krai on the efficiency of using hydroxyapatite to decrease lead intake into plants. The physicochemical characteristics of Luvic Anthrosol and Gleyic Cambisol and their absorption properties with respect to lead have been studied. Adsorption, distribution of forms, and biotesting were carried out under lead saturation of soils conditions. It has been found that soil composition determines sorption properties and the proportion of mobile lead. The high organic carbon content in Gleyic Cambisol explains its high adsorption capacity and low content of water-soluble lead fraction. The addition of hydroxyapatite reduces the water solubility of lead in Luvic Anthrosol by three orders of magnitude and in the ion mobile form by one order. The capacity of hydroxyapatite decreases by more than thirty times when added to Luvic Anthrosol. With a ratio of hydroxyapatite/soil 0.2, oat germination increases by 18.7%, average seedling length increases by 7 cm, and lead uptake into tissues decreases by 83%.