Soil-to-resource approach to assess the Ni hyperaccumulating potential of native plant species for phytomining at Ginigalpelessa serpentinite deposit, Sri Lanka

Emerging clean energy transition technologies have expanded the range of nickel (Ni) applications, making it a critical metal in the metal industry. With the increasing demand, high-grade deposits are incapable of fulfilling continuous supply, and therefore, Ni recovery from low-grade deposits such as serpentine soils has gained wide attention. In this context, phytomining has been identified as a viable approach for Ni mining from low-grade serpentinite deposits due to the abundance of Ni hyperaccumulators. Ginigalpelessa serpentinite deposit in Sri Lanka has been recognized as a potential area for Ni phytomining as the soil contains a high concentration of Ni. The present study aimed to determine the Ni and other valuable metal distribution within the deposit and assess the Ni hyperaccumulation potential of native species for phytomining. Therefore, soil, rock, and plant samples from 31 sampling locations were analyzed using an Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The total Ni concentration in serpentine soil varied from 4005 to 17,352 mg/kg, where the bioavailable fraction was 1–4%. Among the six plant species considered in hyperaccumulation analysis, Apluda mutica ( A. mutica ) accumulated 2802 ± 1182 mg/kg of Ni in its shoot biomass, exceeding the hyperaccumulator threshold limits (1000 mg/kg). The bioconcentration factor (BCF) of Ni and Co for all the selected species was > 1, showing the highest value in A. mutica species (8.26). The translocation ability of Ni in A. mutica (3.06) also indicates the potential of Ni phytomining using the plant species. The findings of this study should be further developed to prospect the phytomining potential in the Ginigalpelessa serpentinite deposit.