Phytoremediation Potentials of Cynodon dactylon on Heavy Metal Contaminated Soils from Challawa Industrial Estate, Kano-Nigeria

Abstract

This study investigated the phytoremediation potentials of Cynodon dactylon in heavy metal contaminated soils of Challawa Industrial Estate, Kano, Kano State, Nigeria. A total of 100 samples comprising of 50 soils and 50 plant parts of C. dactylon were evaluated for the presence of heavy metals by the use of atomic absorption spectrophotometry (AAS) method. Extent of heavy metal soil contamination and phytoremediation potentials of the study plant were assessed by the use of metal contamination factor (Cf) for soil; Bioaccumulation and translocation factors for the plant sample respectively. From the results, levels (mg/kg) of the metals in the C. dactylon from contaminated and control sites were found to be in the sequence of Fe (442.60) > Cu (138.35) > Zn (133.53) > Cd (61.50) > Pb (42.47) > Mn (28.40) > Ni (18.40) > Cr (17.73) and Fe (88.60) > Zn (38.18) > Cu (33.60) > Ni (13.70) > Mn (12.67) > Pb (6.07) > Cd (5.60) > Cr (5.03) respectively. The contamination factor values Cf, (mg/kg) of all the metals in the soils were found to be in the sequence of Cd (10.73) > Cu (5.64) > Cr (3.07) > Pb (2.98) > Ni (2.17) > Zn (2.09) > Mn (2.00) > Fe (1.72). The results showed that the soils are highly contaminated with Cd, considerably contaminated with Cu and Cr, and moderately contaminated with Fe, Mn, Zn, Ni and Pb. The bioaccumulation and translocation factor values (BAF>1 and TF<1) for Cd, Cr, Cu, Mn, Ni, Pb and Zn suggest accumulation in roots and qualify the plant as good candidate for phytostabilization. Moreover, the bioaccumulation and translocation factor values (BAF and TF>1) for the plant species were greater than 1 for Fe suggesting efficient accumulation in the shoot. However, C. dactylon could be recommended as good candidate for phytoextraction of Fe and phytostabilization of the study investigated metals (Cd, Cr, Cu, Mn, Ni, Pb and Zn) in multi-metal contaminated soils.