Articles

Costus afer, a known medicinal plant used in the removal of total monocyclic aromatic hydrocarbon (TMAH) in crude oil-contaminated soil add to the list of plant that has the potential to restore the soil quality. This study investigated the potential of <i>Costus</i><i> </i><i>afer</i> plant at various ages (7, 14, 21, 28, 35, and 42 days old) to biodegrade crude oil-contaminated soil. The group-balanced block design (GBBD) was used in establishing the experiment. TMAH was quantified by the standard method, according to USEPA method using gas chromatography-mass spectrometry (GC-MS). The contamination of 48kg of sandy loam 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 (C<SUB>1</SUB>), medium(C<SUB>2</SUB>), and high(C<SUB>3</SUB>) contamination, respectively. An additional vessel with medium-level contaminated soil but no treatment (C<SUB>4</SUB>) served as the control. The <i>Costus</i><i> </i><i>afer</i> 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 <i>Costus</i><i> </i><i>afer</i> plants produced the highest amount of TMAH reduction of 96.5, 39.8, and 32.1%, for C<SUB>1</SUB>, C<SUB>2</SUB> and C<SUB>3</SUB>, respectively, while the control (C<SUB>4</SUB>) was 9.45%. Furthermore, the sequence of TMAH reduction by the plants was 7 days old, 14 days old, 21 days old, 28 days old, 35 days old, and 42 days old. Thus, in addition to its medicinal value, <i>Costus</i><i> </i><i>afer</i> plant also has the potential to biodegrade TMAH in crude oil-contaminated sandy loam soil.

<i>Costus</i><i> </i><i>afer</i> is a well-known medicinal plant abundant in the Niger Delta region of Nigeria. The successful growth of <i>Costus</i><i> </i><i>afer</i> plant on crude oil contaminated soil adds to the list of plants that has potential to get rid of harmful chemical compounds to save human life as well preserve the environment. This study investigates the remediation potential of <i>Costus</i><i> </i><i>afer</i> plant at different ages (7, 14, 21, 28, 35, and 42 days old) to decontaminate petroleum hydrocarbon-contaminated soil. To achieve this, contamination of sandy-loam soil was simulated by mixing T0.5, 1.0, and 1.5 L of Bonny-Light crude oil with 48 kg of the soil in three separate reactors to achieve conditions of low, medium, and high contamination, respectively. The reactor with medium-level contaminated soil served as the control. The plants were nursed and transplanted at the stated ages to each reactor 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 plants produced the highest amounts of total polycyclic aromatic hydrocarbon (TPAH) reduction of 99.71, 90.10, and 84.06 % in the soil with low, medium, and high contamination, respectively. Furthermore, the sequence of TPAH reduction by the plants was 14 days old > 21 days old > 28 days old > 35 days old > 42-days old. Thus, in addition to its medicinal value, <i>Costus</i><i> </i><i>afer</i> plant also has the potential to restore crude oil-contaminated soils.