Research Article
Phytoremediation of Petrol-Contaminated Soil Using Ficus Racemosa L. Amended with Poultry Droppings
1 Department of Agriculture, Federal University of Technology, Ikot Abasi, PMB 1055, Ikot Abasi, Akwa Ibom State, Nigeria
2 Department of Plant Sciences, Akwa Ibom State University, Ikot Akpaden, Akwa Ibom State, Nigeria
Abstract
Petroleum hydrocarbon contamination of agricultural and peri-urban soils is a persistent problem in oil-producing regions of Nigeria, yet plant species evaluated for its phytoremediation remain narrow, dominated by grasses and a few leguminous species. This study evaluated the phytoremediation potential of Ficus racemosa L., an ecologically and medicinally important woody species untested for this purpose, in petrol-contaminated soil amended with poultry droppings. Seedlings were grown for 12 weeks in soil contaminated with Premium Motor Spirit at approximately 4% (v/w) (initial TPH concentration 5000 mg kg⁻¹), in a Completely Randomized Design with an uncontaminated planted control, unplanted unamended and amended baselines, and planted unamended and amended treatments, replicated three times. Growth parameters, chlorophyll content, root length, TPH removal, and soil pH recovery were assessed. Unamended contamination severely suppressed growth and physiological parameters relative to the control; unplanted, unamended soil achieved only 18.00 ± 1.10% TPH removal after 12 weeks via natural attenuation. Poultry-droppings amendment and F. racemosa independently improved removal (48.00 ± 1.42% and 66.00 ± 1.35%), while their combination removed 87.00 ± 0.95%, reducing residual TPH to 650 ± 26 mg kg⁻¹. The combined treatment also restored soil pH from 5.20 ± 0.03 to 6.80 ± 0.04, matching the control, and produced growth, chlorophyll, and root-length values equalling or exceeding control values by Week 10. These findings identify F. racemosa as a previously untested, locally available candidate for petroleum-hydrocarbon phytoremediation, and show its combination with a low-cost, widely available organic amendment achieves faster, more complete remediation than either intervention alone.
Keywords: Phytoremediation; Ficus racemosa; petroleum hydrocarbon; poultry droppings; bioaugmentation; soil contamination
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