Abstract:
Contamination of soil by crude oil has caused more harm than good to our environment. The use of locally sourced environmental remediation stimulants brings the hope of inventing such products to be reality for today's intractable environmental contamination conditions. This will make way for the subsequent usage of more quantity to restore contaminated soil. Despite the high nutrient composition of Costus afer juice, it has been an elusive to be used as biostomulants for soil remediation. This study evaluated the potentials of Costus afer juice for bioremediation of crude oil contaminated soil. The experiment was carried out in Teaching and Research Farm of Rivers State University, Port-Harcourt. Soil samples with crude oil were bulk in five (5) cells (T1, T2, T3, T4, T5) with three replications each. The physiochemical properties of treated soil and Costus afer juice such as particle size distribution (PSD), nitrogen, phosphorus (P), potassium (K), total petroleum hydrocarbon (TPH), total polycyclic aromatic hydrocarbon (TPAH), total heterotrophic bacteria (THB) were analyzed in the laboratory before and after treatment. The results showed that the soil is a loamy sand soil, and Costus afer juice has a high NPK values that proved it as biostimulant. TPH and PAH also reduced severely in all the treatment options at the end of the remediation period of 8 weeks, and their percentage reductions were above 94% in all treatment options for the same period. Moreover, Analysis of Variance (ANOVA) result showed significant difference at 95% confidence levels. Furthermore, there were increase in the number of THB and later reduce as the stimulants reduced after gotten to its peak within eight (8) weeks of remediation. It is therefore recommended that the Costus afers juice can serve a good biostimulant that should be used for degradation of TPH and PAH in crude oil contaminated soil.
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