Effect of detergent and sawdust addition on hydrocarbon reduction and growth of Abelmoschus esculentus L (Okra) in a petroleum-contaminated soil

Abstract

A study to investigate the effect of sawdust and detergent on hydrocarbon reduction and the growth of okra (Abelmoschus esculentus L.) in petroleum polluted soil was carried out. The study was conducted at the Centre for Ecological Studies, University of Port Harcourt. Bonny light crude (300 ml) was used to pollute 10 kg soil. Detergent (20 g), sawdust (200 g) and sawdust: detergent (200 g: 20 g) were used as the amendment materials alongside a control (pollution but un-remediated) arranged in a completely randomized design of 12 replications. After 30 days post-amendment, 3 seeds of okra (var: V35-45 days) were grown in each treatment pot for 6 weeks. Soil Total Hydrocarbon Content (THC) and okra growth performance (shoot length, leaf number, root length, total fresh weight, dry weight, leaf area and leaf area ratio) were analyzed. Results showed significant (p=0.05) reductions in THC of 44.23%, 26.5%, 70.80% and 10.79%, in detergent (20 g), sawdust (200 g), sawdust (200 g) + detergent (20 g) and control, respectively. Improved growth performances of okra were observed in the amended soil as compared to the control. Okra growth performance was in the order of: 200 g sawdust + 20 g detergent combination > 200 g sawdust > 20 g detergent. This implies that these two materials are good bio-stimulation materials especially when used in combined form for THC reduction and growth of okra.

Keywords: Abelmoschus esculentus L., contamination, crude oil, sawdust, total hydrocarbon content