Migration Behavior of ⁹⁰Sr in the Soil-Plant System and Phytoremediation: A Review

⁹⁰Sr is a representative anthropogenic radionuclide, widely released into the environment through atmospheric nuclear tests, nuclear accidents, and routine operations of nuclear facilities, resulting in long-term residual contamination in soils worldwide. Its long half-life, high mobility, and chemical similarity to calcium make it easy to enter the food chain through the soil-plant system, thereby posing a persistent threat to ecosystems and human health. Conventional physical and chemical remediation approaches are often costly, ecologically disruptive, and inefficient for large-scale applications, highlighting an urgent need for sustainable, in situ strategies. Moreover, existing knowledge on ⁹⁰Sr behavior has largely been generated from isolated studies, lacking an integrated framework to guide remediation efforts. This review summarizes the migration mechanisms of ⁹⁰Sr in the soil-plant system and the main factors influencing its transport and accumulation. In soil, the migration of ⁹⁰Sr is jointly controlled by soil texture and mineral composition, competing cations, organic matter, soil pH, and moisture, with cation exchange acting as the main immobilization mechanism. Plant uptake and accumulation of ⁹⁰Sr show distinct inter- and intra-species differences, and the distribution generally follows the pattern of vegetative organs > reproductive organs. This process is regulated by root activity, transpiration, and competition with Ca²⁺ transport channels. Agronomic practices such as liming, deep plowing, and balanced fertilization can effectively reduce the phytoavailability of ⁹⁰Sr by promoting ion competition and modifying the rhizosphere environment. Meanwhile, phytoremediation offers a promising green approach for the remediation of contaminated soils. Overall, this review provides a theoretical basis and scientific reference for the risk management and bioremediation of ⁹⁰Sr in soil-plant systems.