Evaluation of sphagneticola trilobata and amaranthus hypochondriacus on the phytoremediation of soils polluted by heavy metals

Soil pollution by heavy metals is a major environmental problem. Heavy metals can seep through the soil layers to pollute groundwater or surface water through runoff and enter the food chain causing major health problems for humans and biodiversity. This study was conducted to assess the phytoremediation potential of two plant species, the sphagneticola trilobata, and, amaranthus hypochondriacus, in soils polluted with lead (Pb), nickel (Ni), and zinc (Zn) using the atomic absorption spectrophotometer (AAS) method. The results showed that the two plant species absorbed heavy metals differently. The sphagneticola trilobata absorbed Pb the least with an average concentration, ranked highest to lowest, of 2.334 mg/kg, 1.409 mg/kg, and 1.399 mg/kg for the leaves, roots, and stems, respectively, over 4 months. However, Zn accumulated the most in the same plant with concentration values, ranked highest to lowest, of 2.576 mg/kg, 2.398 mg/kg, and 2.061 mg/kg for the roots, leaves, and stems, respectively, over 4 months. Overall, amaranthus hypochondriacus was the only species that absorbed Ni, with low average concentrations compared to Pb and Zn. The average concentration values for amaranthus hypochondriacus, ranked lowest to highest, were: Ni (1.600, 1.493, 1.358 mg/kg), Pb (2.018, 1.965, 2.285 mg/kg) and Zn (6.426, 4.767, 5.820 mg/kg) for leaves, stems and roots respectively for all metals. Therefore, a bioaccumulation factor (BCF) < 1 for all plants and a translocation factor (TF) > 1 indicates the sphagneticola trilobata is a phytoextractor of Pb and Zn, and the amaranthus hypochondriacus can be used as a phytoextractor of Pb, Ni, and Zn in soil.