Assessment of Phytoremediation Potential of IndigenousFlora around the Steel Industries in Nigeria Ajaokuta SteelCompany Limited, Ajaokuta, Kogi State, Nigeria

Abstract

In recent years, with the development of the global industrialization, the content of heavy metals in the soil caused by industrial activities has gradually increased, resulting in environmental deterioration. There is a need to provide viable option that is economical, environmental friendly and sustainable for clean-up of environmental contamination such as phytoremediation. Series of studies conducted in the past on heavy metals content in soil around Ajaokuta Steel Company Limited (ASCL) without considering the remediation technologies of such contents. This study primarily assessed the phytoremedial potential of indigenous flora around Ajaokuta Steel Company Limited Ajaokuta, Kogi State, Nigeria. To achieve this, top and sub soil samples along with control were collected around the vicinity of ASCL for heavy metals analysis. Four different indigenous plants (Imperata cylindrica (Spear grass or cotton wool grass), Sida acuta (Wire weed), Helianthus annuus (Sunflower) and Chromoleana odarata (Siam weed) grown within the vicinity of the ASCL were randomly collected for heavy metals analysis. The samples were digested and analyzed using Atomic Absorption Spectrophotometer (AAS) (Perkin Elmer® Analyst 100 model). The data obtained were analyzed using SPSS 20 for descriptive and inferential statistics. The metal transfer factors were also determined. The results obtained revealed that the potential of remediating Lead by C. odarata was high compared to other plant species which uptake 10.33 mg/kg, 20.11 mg/kg, and 25.32 mg/kg in the leaves, stem and root respectively. The bioaccumulation level of Lead in C. odarata and H. annus were recorded to be 0.91 mg/kg and 0.71 mg/kg respectively which indicated highest bioaccumulation factor. Unlike the bioaccumulation factors, the translocation factors were high in all the heavy metals investigated. The study revealed that C. odarata, I. cylindrica and S. acuta are good accumulators of heavy metals and they should therefore be encouraged to be cultivated. The plant species may be regarded as hyperaccumulators, which is characterized by their ability to accumulate high quantities of metals in their tissues.