Effect of Woodchips on Bioremediation of Crude Oil-polluted Soil

Abstract

Aims: To evaluate the effectiveness of woodchips in bioremediation of crude oil contaminated soil, phytotoxicity assay as an index of soil biological activities (germination index) using a selected agricultural seed (Vicia faba) was also evaluated. Methodology: Soil sample collection from Aguleri and Nkwelle Ezunaka, both in Anambra State. Samples were stored in polythene bags and transported to the laboratory. The soil samples were air dried, sieved through 2 mm mesh and stored in polythene bags at room temperature. Results: Results showed that relatively alkaline pH was observed in woodchips amended option while slight acidity was reported in the control soil. Using woodchips as biostimulant achieved 75% crude oil contaminant removal but only 50% in the control. The microorganisms isolated from the present study included Klebsiella spp Pseudomonas spp Candida spp Fusarium, Penicillium spp.  Only 50% woodchips amended system produced growth of Vicia faba after 5 days incubation. There was no growth of Vicia fabaat 10% and 30% of woodchips at the same incubation time. Conclusion: Result of the present study showed that hydrocarbon removal from the lithosphere can occur either naturally or by strategy enhancement with amendments but posited that rate and extent of removal in each case always differ. Present study also proved that for recovery of polluted media such as soil, information on the concentration of the additional limiting factors is scientifically crucial. 50% woodchips supported high crude oil remediation in the polluted soil. Woodchips therefore, is a potential source of nutrients for microbial activity and it habours microorganisms capable of utilizing hydrocarbons as source of carbon and energy thus, potentially useful in soil hydrocarbon spill response action.