Heavy Metal Concentration and Physicochemical Changes of Soil Treated with Spent Engine Oil and Organic Manure (Poultry) After 12 Weeks of Growing Cyperus compressus L.

ABSTRACT: Heavy metal concentration and physicochemical changes of soil treated with spent engine oil (SEO) and poultry manure after 12 weeks of growing Cyperus compressus was this study’s aim. Poultry manure (PM) was 10 % of 4000g (400 g) while the soil was 3600 g. Spent engine oil was added to 4000 gr of mixed soil and PM at different concentrations: 0 mL (control), 40 mL (1 %), 120 mL (3 %) and 220 mL (5 %) v/w oil-in-soil and allowed to stand for seven days in the sack bags before planting. Field observation was carried out.  At the end of 12 weeks of growth, the plants were removed. Initial soil and raw SEO samples were subjected to heavy metal analysis (Zn, Hg, Mn, Fe, Pb, Cu, Cr, and Cd). Thereafter, soil after 12 weeks of Cyperus compressus culture were also subjected to physical, chemical and heavy metal analysis. The data obtained were subjected to T-test and Analysis of Variance (ANOVA) test respectively.  The result obtained showed that there was significant difference (P≤0.05) in the concentration of initial heavy metals in untreated soil and that of raw SEO. Treatment effects on differences in mean was significant (P≤0.05) at all levels, to soil physical parameters, chemical parameters, and heavy metal parameters treated with varying levels of SEO. However, Pb was not detected in the soil samples at all levels. Finally, the plant has demonstrated its potentials in heavy metal uptake, hence, this C. compressus can be adopted for recovering hydrocarbon-polluted soil.