Vermicompost Assisted Phytoremediation of Heavy Metal Contaminated Soil in Madaka District, Nigeria Using Melissa officinalis L (Lemon balm) and Sida acuta (Stubborn weed)

This research was designed to clean-up through an environmentally friendly techniques, a polluted environment of Madaka District of Shikira. Physicochemical properties of the soil were done using standard methods. Chicken dropping vermicompost (CDV) and goat manure vermicompost (GMV) were produced by standard method to assist the phytoremediation process with plant growth promoting bacteria (PGPB). Canonical discriminant functions of the heavy metals were done. For the first location (AK) the plant parts of M. officinalis L mopped up heavy metals, the concentration of Cd, As, Pb in plant parts varied from 0.007 to 0.33 mg/kg, As from 0.09 to 4.39 mg/ kg and Pb from 0.07 to 10.35 mg/kg respectively while the concentration of heavy metals in S. acuta parts had Cd, As, Pb varied from 0.002 to 0.43 mg/kg, As from 0.27 to 3.79 mg/ kg and Pb from 1.68 to 10.7 mg/kg respectively. The second location (AM) also had the two plants mopping up heavy metals at different concentrations. the concentration of Cd, As, Pb in M. officinalis L parts varied from 0.03 to 0.41 mg/kg, As from 0.65 to 4.65 mg/ kg and Pb from 1.93 to 11.49 mg/kg respectively while the concentration of heavy metals in S. acuta parts had Cd, As, Pb varied from 0.06 to 0.66 mg/kg, As from 0.68 to 4.64 mg/ kg and Pb from 1.53 to 11.53 mg/kg respectively. Melissa offinalis L and Sida acuta were found most suitable for phytoextraction of sites contaminated with Cd, As and Pb because both of them have their bioconcentration factor (BCF), translocation factor (TF) and biological accumulation coefficient (BAC) to be ˃1 while both were also scored as phytostabilizer because they have BCF ˃1 and TF ˂1. Soil structural changes pre and post remediation were determined through x-ray fluorescence (XRF spectroscopy) and scanning electron microscopy (SEM) analyses.