Quantitative tomography of contaminant phytomobilization: β+ emitters 83Sr and 86Y as tracers of fission-product analog mobility

• Novel 83 Sr 2+ and 86 Y 3+ radiotracers track fission product mobility in soils. • High-resolution positron emission tomography (PET) quantifies phytoremediation. • Tomography of chelator-enhanced contaminant mobilities in soil-like substrates. The mobility of fission-product analogs in sandy soil and phytoremediation contexts was investigated using positron emission tomography (PET) 83 Sr 2+ and 86 Y 3+ β⁺ tracers. Flow experiments in quartz and FeOOH-coated sands revealed limited baseline mobility of 86 Y 3+ . Chelating agents enhanced transport: citrate mobilized 86 Y 3+ in quartz sand, while NTA was required for FeOOH-coated sand. Phosphate reduced citrate-driven mobilization, highlighting chemical controls on rare earth element transport relevant in the phytoremediation context. High-resolution 83 Sr 2+ PET captured millimeter-scale heterogeneities in hydrodynamics, with ammonium nitrate mobilization producing mean velocities of 55.8 mm·h⁻¹. Phytomobilization experiments with Avena strigosa demonstrated plant-mediated contaminant movement. Localized radiotracer injections remained confined due to strong adsorption, with 83 Sr 2+ showing tracer cloud velocities of 33–360 μm·h⁻¹ and 86 Y exhibiting minimal mobilization. Detection of radiotracer concentrations down to 0.1 fmol·mm⁻³ provides quantitative insight into substrate-dependent transport processes. The results validate the capabilities of PET for high-resolution quantification of radiometal mobility in both abiotic and plant-mediated remediation scenarios. The datasets provide an estimate for assessing the time-scales on which remediation efforts should be planned. In addition, the introduction of novel radiotracers, experimental designs and methods for data validation lay the groundwork for ex-situ research concerning remediation and environmental safety.