Evaluation of phytoremediation potentials of different plants’ varieties in petroleum products polluted soil

Abstract

A pot experiment was conducted to evaluate the effect of three groundnut varieties (SAMNUT 10, SAMNUT 11 and SAMNUT 22) and two spinach varieties (African Spinach and Feather Cockscomb) on the Total Hydrocarbon Content (THC) on soil samples. Plastic buckets filled with 10 kg of topsoil were pounded daily with a mixture of 1 L of spent engine oil, 1 L of kerosene, 1 L of petrol and 1 L of diesel for ten days, before they were left to stabilize for a period of three weeks. Plant and soil THC analysis were done using standard methods approved by ASTM D 9071B. Test results showed that Arachis hypogaea and spinach plants had significant effect (p≤0.05) on the THC of the contaminated soil samples. From the results, Arachis hypogaea was able to degrade the THC from 1024 mg/kg to 133.31 mg/kg (about 86% reduction), while the spinach was able to degrade the THC from 1024 mg/kg to 192.98 mg/kg (about 80% reduction) within the experimental period of 14 weeks. In addition, the results showed presence of THC in the plant (root and leaf), with higher concentration (about 90 mg/kg for Arachis hypogaea and 72 mg/kg for spinach) in the roots than in the leaves (about 56 mg/kg for Arachis hypogaea and 38 mg/kg for spinach). The results obtained will help to evaluate the use of phytoremediation to clean up soils contaminated with petroleum products.