Phytoremediation potential of pioneer plants in mercury contaminated mined soil at an abandoned mined site in ghana

Abstract

Mercury contamination at abandoned mined sites poses serious environmental and public health risks in sub-Saharan Africa, while affordable and sustainable remediation options remain limited. This study evaluated the phytoremediation potential of three native plant species, Mucuna pruriens var. utilis, Rottboellia cochinchinensis, and Elaeis guineensis that naturally regenerated on an abandoned mined site in Amanchia, Ghana. Soil analyses showed a mean mercury concentration of 2.55 ± 0.15 mg/kg, indicating very high contamination relative to background levels. Bioaccumulation factors for all species were below 0.05, demonstrating limited mercury uptake. Translocation factors ranged from 0.72 to 0.79, reflecting moderate internal mobility but insufficient transfer to shoots for effective phytoextraction. R. cochinchinensis recorded the highest mercury accumulation in both roots and shoots, although none of the species met the criteria for mercury hyperaccumulation. These findings support existing evidence that confirmed mercury hyperaccumulators are rare or absent and highlight phytostabilization as a more suitable approach than phytoextraction for mercury-impacted soils. The study underscores the ecological value of indigenous pioneer species in limiting mercury mobility and recommends further research into plant–microbe interactions and soil amendments to enhance stabilization outcomes in degraded mining landscapes.