Abstract

These study is to evaluate the phytoremediation ofselected heavy metals (cadmium, lead and iron) in a spent oil contaminated soil using iron weed augmented with pig dung, physiological paiameters such as total nitrogen. The sample (pig dung) was collected from a ranch while the soil samples were obtained from the top soil (0 — 15 cm), collected from non-contaminated area. These locations are within the campus of Michael Okpara University of Agriculture, Umudike. These samples were grouped into five (5) different groups viz: group 1 served as control while group 2 was Soil + spent oil and, group 3 was Soil + spent oil + pig dung. Groups 4 and 5 were Soil + spent oil + iron weed and Soil + spent oil + pig dung + iron weed, respectively. These groupings were made for both uncontaminated and contaminated soil, each. The results for cadmium concentration shows 0.90+0.51, 0.49±0.03 on control, 1.45+1.03, 0.49±0.01 on spent oil, 0.03±0.01, 0.12+0.02, on spent oil+ iron weed, 0.00+0.00, 0.83+0.03 on Spent oil+ pig dung+ iron weed and that of lead shows 2.04+0.03, 3.78+0.02on control, 1.98+0.01, 6.55+0.01 on spent oil, 0.01+0.01, 8.55+0.01, on spent oil+ pig iron weed, 0.00+0.00, 2.45+0.00 on Spent oil+ pig dung+ iron weed and that of iron were observed to be; 611.09+0.04, 1137.36+0.03 on control, 736.10+0.04, 1137.36+2.05 on spent oil, 664.10+0.35, 656.23+0.55, on Spent oil + iron weed, 542.2+0.99, 699.48+0.51 on Spent oil + pig dung + plant. The bioaccumulation factor showed hyperaccumulation of both cadmium and iron (1.79 and 1.04 respectively). With respect to physico-chemical parameters analysed, total organic matter of both contaminated and uncontaminated showedan increase in group 5 (Spent oil + pig dung + Iron weed) (0.31+0.00) when compared with other groups while result of cation exchange capacity showed significant (p<0.05) increase in group 3, 4 and 5 when compared with group 1 and 2. From these results, it was observed that the plant - little iron weed had a positive effect on polluted soil samples and therefore, recommended for use in phytoremediation.