Phytoremediation of Petroleum Hydrocarbon-Contaminated Soil using Costus afer Plant

The successful application of the well-known medicinal plant, Costus afer, in the restoration of petroleum hydrocarbon-contaminated soil adds to the list of what the plant can potentially do to rid the environment of harmful chemical compounds to enhance human and environmental health. This study investigated the potential of Costus afer plant at various ages (7, 14, 21, 28, 35, and 42 days old) to restore petroleum hydrocarboncontaminated soil. The contamination of 48kg of sandyloam soil was simulated by mixing 0.5, 1.0, and 1.5L of Bonny-Light crude oil with the soil in three separate vessels to achieve conditions of low, medium, and high contamination, respectively. An additional vessel with medium-level contaminated soil served as the control. The Costus afer plants were nursed and transplanted at the stated ages to each vessel except the control. Controlled irrigation was applied, and the setups were housed to shield them from rainfall. After 90 days of treatment, results showed that the 7 days old Costus afer plants produced the highest amounts of total petroleum hydrocarbon (TPH) reduction of 97.42, 94.64, and 95.12% in the soil with low, medium, and high contamination, respectively. Furthermore, the sequence of TPH reduction by the plants was 14 days old, 21 days old, 28 days old, 35 days old, and 42 days old. Thus, in addition to its medicinal value, Costus afer plant also has the potential to decontaminate petroleum hydrocarbon contaminated soils.