Phytoremediation Potential of Heavy Metals Using Vetiver and Elephant Grass Obtained from Maiganga Gombe Nigeria

Abstract

Heavy metal contamination of soils poses a significant environmental challenge due to its persistence, toxicity, and potential for bioaccumulation in food chains. This study evaluated the comparative phytoremediation potential of Vetiver grass (Chrysopogon zizanioides) and Elephant grass (Pennisetum purpureum) in cadmium (Cd)- and nickel (Ni)-contaminated soil under controlled pot conditions. A completely randomized experimental design was employed using five graded concentrations of heavy metals (12.5–200 mg/kg) alongside a control, with each treatment replicated three times. Soil physicochemical properties were determined prior to experimentation, while metal concentrations in soil, roots, and shoots were analyzed using atomic absorption spectrophotometry following acid digestion. Phytoremediation efficiency was assessed using bioconcentration factor (BCF) and translocation factor (TF).
Results indicated that Vetiver grass predominantly accumulated Cd and Ni in its roots, exhibiting BCF values greater than 1.0 for Cd and consistently low TF values (<1.0), indicating strong phytostabilization potential. In contrast, Elephant grass demonstrated higher translocation of both metals to aerial tissues, with TF values frequently exceeding 1.0, particularly for Cd, indicating strong phytoextraction capability. Cd accumulation was generally higher than Ni accumulation across both species and increased proportionally with applied concentrations. Soil physicochemical characteristics, particularly low organic carbon and moderate cation exchange capacity, were found to influence metal availability and uptake dynamics.
Overall, Vetiver grass functioned primarily as a phytostabilizer, while Elephant grass exhibited greater potential as a phytoextractor. The findings suggest that both species can be strategically applied in phytoremediation programs depending on site-specific remediation objectives, with Vetiver suited for metal stabilization and Elephant grass for contaminant removal through biomass harvesting.