Abstract
This systematic review analyzes the cadmium (Cd) stabilization mechanisms mediated by nanobubbles (NB) to mitigate its accumulation in Peruvian cacao crops, ensuring compliance with EU Regulation 488/2014. Following PRISMA 2020 guidelines, 63 high-impact studies were synthesized. The findings reveal that the high internal pressure and longevity exceeding 21 days of NBs facilitate sustained oxygen mass transfer, which dynamically increases the soil redox potential (Eh). A mean immobilization efficiency of 50.7 % was identified, which can exceed 70 % through the optimization of gas precursors and internal pressure, effectively shifting Cd toward stable residual fractions. Furthermore, the negative zeta potential of NBs promotes the electrostatic capture of Cd2+ cations, while oxygen saturation in the rhizosphere alters the gene expression of root metal transporters, significantly reducing translocation to the bean. It is concluded that the regulation of these transporters represents a high-precision biotechnological strategy to ensure food safety and the economic sustainability of cacao exporters in the San Martín region.
