Heavy metal pollution indices in soil and plants within the vicinity of the Gosa Dumpsite in Abuja, Nigeria

Heavy metal contamination in the soil and phytoremediation potential of the plants cultivated around the Gosa dumpsite were evaluated using pollution indices. The concentrations of heavy metals in the soil and plant samples were determined using an atomic absorption spectrophotometer (Agilent 280FS AA). The mean heavy metal contents in the upper and lower soil layers ranged from 0.37 to 1662.61 mg/kg and 0.32 to 1608.61 mg/kg, respectively, in ascending order of Cd Ni. The soil was moderately polluted with Co, Cu, Pb, Zn, Fe and Cd but heavily polluted with Cr and Ni. The results revealed that 37.5% of the sites studied had pollution load indices greater than 1.0, indicating gradual deterioration in overall soil quality. The concentrations of Pb, Cd and Fe exceeded the recommended limits for the five plant species assessed. The transfer factor (TF) values of okra plant 1 (0.7536), water hyacinth (1.3768) , and Amaranthus hybridus (0.9783) indicated excellent Cd phytoremediation potential. Okra Plant, water hyacinth and Amaranthus hybridus had excellent potential for phytoremediation of Cu, Fe and Pb, respectively. The study area was strongly enriched in Fe, Cd, Cr, and Ni, suggesting some degree of soil pollution, while the plants demonstrated an excellent capacity to accumulate Cd, Cu, Fe and Pb. This dumpsite should be adequately monitored while proper remediation measures are adopted by government authorities.