Effect of mycorrhizal inoculation and organic fertiliser on bioremediation of spent engine oil contaminated soil

Abstract

Hydrocarbon-related environmental pollution is a major environmental hazard due to its toxicity and widespread presence in the environment, resulting in stunted growth of soil microorganisms, plants, and animals. This study was therefore conducted to evaluate the effect of mycorrhizal inoculation and compost made from Cocoa Pod Husk (CPH) and cattle dung in the bioremediation of Spent Engine Oil (SEO)-contaminated soil. About 2.5 kg of sterilised soil was contaminated with SEO at different concentrations: 0, 100, and 150 mL / pot. Compost was then added after two weeks of contamination at the rate of 10 g / pot. Inoculation for treatments containing Glomus mossaea (consisting of 20 g of root soil-fungal mixture) was blended into the soil samples as well. It was a 2 × 2 × 3 factorial experiment that was laid out in a completely randomised design and replicated three times. The incubation was allowed to last for twelve (12) weeks before the termination of the experiment. Data were collected on the Total Petroleum Hydrocarbon (TPH), bacterial and fungal biomass of the SEO-contaminated soil. Results obtained indicate that combined application of mycorrhiza with 100 mL / pot SEO resulted in significantly (p < 0.05) lower residual TPH content (54.50% degradation) of the contaminated soil compared to the other treatment combinations whereas significantly higher residual TPH content (20.43% degradation) of the contaminated soil was obtained from the interaction between 150 mL / pot SEO and without mycorrhizal inoculation. Interaction between mycorrhiza and 10 g / pot compost had a significantly higher bacterial colony (6.58 CFU / g) compared to other treatment combinations. Mycorrhizal inoculation resulted in a significantly higher fungal colony (5.844 CFU / g) compared with non-mycorrhizal inoculation (3.222 CFU / g). Therefore, it can be concluded that mycorrhizal inoculation and compost were effective in the bioremediation of SEO-impacted soil.

Potential of Mycorrhizal Inoculation and Cattle Rumen Digesta in the Bioremediation of Spent Engine Oil Contaminated Soil

“…Mycorrhizal application resulted in enhanced TPH degradation in the SEO contaminated soil. A similar result was also obtained by Nkereuwem et al (2022Nkereuwem et al ( , 2020a where they observed reductions in TPH content of crude oil-contaminated soil. The reduction in TPH content could be due to the fact that mycorrhizal fungi interact with some other beneficial soil organisms in order to achieve complete clean-up of polluted soils (Chibuike, 2013).…”

“…Cattle rumen digesta is recommended for use in bioremediation because it enhances soil nutrient utilization and reduces pollution (Cherdthong, 2020). It is possible to both remediate the contaminated soil in situ and revegetate the region at the same time if the right mycorrhizal fungus is introduced into the soil (Tangahu et al, 2011;Nkereuwem et al, 2022). Over time, bioremediation technology has demonstrated positive results in eliminating hydrocarbon levels from affected ecosystems (Nkereuwem et al, 2022;Nkereuwem et al, 2020a;Adeleye et al, 2021).…”

“…It is possible to both remediate the contaminated soil in situ and revegetate the region at the same time if the right mycorrhizal fungus is introduced into the soil (Tangahu et al, 2011;Nkereuwem et al, 2022). Over time, bioremediation technology has demonstrated positive results in eliminating hydrocarbon levels from affected ecosystems (Nkereuwem et al, 2022;Nkereuwem et al, 2020a;Adeleye et al, 2021). These bioremediation techniques are economically and ecologically attractive.…”