Bioremediating Effect of Glomus Hoi and Pseudomonas Aeruginosa on the Organic Content and Heavy Metals of Soil Polluted with Oil Refinery Effluent using Amaranthus Cruentus as a Test Plant

This study analyzed the degrading effect of Glomus hoi and Pseudomonas aeruginosa on the organic content and heavy metals of oil refinery effluent polluted soil using Amaranthus cruentus as the test plant. This study was carried out to determine if agricultural activities can be improved using any or both of the micoorganisms. Eight different treatment layouts were used with three replicates for each level of pollution in the treatment layout. Ninety six (96) pots, each containing three kilograms of soil from both sterilized and unsterilized soil were used for the study. Fifty (50) grams of soil inoculum from propagated Arbuscular mycorrhiza was inoculated to a set of twenty four (24) experimental pots containing both sterilized and unsterilized soil before A. cruentus seedlings were transplanted to them. Another set of twenty four (24) pots containing both sterilized and unsterilized soil were injected with thirty (30) mL of P. aeruginosa inoculum solution before transplanting A. cruentus seedlings to them. The third set of twenty four (24) pots received dual inoculation of both fifty (50) grams of soil inoculum containing G. hoi and thirty (30) mL of P. aeruginosa inoculum solution before A. cruentus were transplanted to them. The residual twenty four (24) pots served as the control. Thereafter, pot preparation was arranged in the screenhouse in a randomized block design. The A. cruentus seedlings were raised in nursery for a period of two weeks before they were transplanted to the pots, seedlings were left for 3 days to overcome transplanting shock before contaminating the soil with refinery effluent at various concentrations of 0%, 2%, 4% and 6% v/w. The seedlings were allowed to grow for eight weeks before the termination of the experiment. The pre planting analysis of soil showed that heavy metals analyses (zinc and iron) of sterilized soil had a lower concentration to the unsterilized. The soil pH ranged from 6.3 to 6.8. It also revealed that organic matter and organic carbon content ranged from 0.8% to 1.3% and 0.4% to 1.7%. However, after the experiment, it was discovered in this study that treatments without any microorganism inoculation in sterilized and unsterilized soil had a higher level of % organic carbon and % organic matter content compared to the other treatments that were inoculated with one or two micro-organisms across all the levels of effluent concentration. Heavy metals of soil in all the soil samples were found to increase as the petrochemical effluent increased in concentration. The results obtained were analyzed using Duncan Multiple Range Test (DMRT) and other descriptive statistics. This study opined that the combined use of G. hoi and P. aeruginosa was more effective in improving the organic contentand the reduce heavy metals of oil refinery effluent polluted soil than when either is used singly.