PHYTOREMEDIATION POTENTIAL OF MAIZE (Zea mays Linn.) USING POULTRY LITTER ON SOIL POLLUTED WITH SPENT ENGINE OIL

Abstract

This study was carried out to determine the Phytoremediation potential of maize (Zea mays Linn.) using poultry litter on soil polluted with spent engine oil. 100 ml spent engine oil (SEO) was thoroughly mixed with 5 kg of air-dried soil. The spent engine oil (SEO) contaminated soil was treated with five concentrations of poultry litter (PL) in a perforated bucket: pristine control (0 kg PL + 5.0 kg soil), spent engine oil control (0 kg PL + 5.0 kg SEOC soil), 0.5 kg PL + 5.0 kg SEOC soil, 1.0 kg PL + 5.0 kg SEOC soil, 1.5 kg PL + 5.0 kg SEOC soil. The soil treatment was left for thirty (30) days at the end of which soil analysis was conducted and maize seeds are introduced. Maize seeds were grown in the experimental soil in a screen house. The setup was a Completely Randomized Design (CRD) and replicated four times and data was collected for a period of 10 weeks after sowing of seeds. Data were collected on the growth parameters (days to sprouting, number of leaves, plant height, leaf area, stem girth. Data were also collected on yield parameters (fresh and dry weight, and seed proximate), heavy metal analysis was also carried out. Results of the study showed that pH of spent engine oil contaminated soil was 5.19 and 8.2 for poultry litter. After 30 days of treatment, it was shown that poultry litter treatment increased the soil pH from acidic towards neutral. The pH of treated soil PL 0.5 kg + SEOC , PL 1.0 kg + SEOC and PL 1.5 kg + SEOC were 7.49, 7.16, and 7.93 respectively which are suitable for maize growth. Organic Carbon, Nitrogen and Phosphorus in soils increased after treatment with poultry litter and there were significant differences in all treatment levels. The pre-experimental heavy metal analysis indicates that Chromium in the spent engine oil sample was 13.38 ppm, this value reduced to 3.15 ppm (76.5%) in PL 1.0 kg + SEOC. Cadmium (Cd) in the SEO sample was 0.08 ppm. Cd was not detected in PL 1.0 kg + SEOC and PL 1.5 kg + SEOC after treatment. Cobalt and Lead in the spent engine oil sample was 1.19 ppm, and 0.20 ppm respectively, it was reduced to 0.20 ppm (83.2 %) and 0.01 ppm (95 %) respectively in PL 1.5 kg + SEOC. The results of the morphological features on maize plant showed that higher concentration of poultry litter improved the growth and yield of the plant. Plant height was higher in soils treated with poultry litter when compared to the control (PC - 146.52, SEOC - 50.21, PL 0.5 kg + SEOC - 215.90, PL 1.0 kg + SEOC - 217.78, PL 1.5 kg + SEOC - 223.55) at 10 weeks after planting. Highest dry weight was obtained at PL 1.5 kg (71.70) as against the spent engine oil control (1.50). Higher concentrations of poultry litter brought an increase in the total chlorophyll content (PL 1.5 kg + SEOC - 1.82 mg/g, PL 1.0 kg + SEOC - 1.59 mg/g, PL 0.5 kg + SEOC - 1.66 mg/g, SEOC - 0.19 mg/g, PC - 1.0 kg/g). With the exception of chromium, other heavy metals tested for were not detected in the shoots and roots of all poultry litter treated plants unlike in the SEOC where all heavy metals was detected. The proximate analysis showed that there was an increase in the proximate composition of maize fruits grown on poultry litter treated plant compared to the pristine control while the SEOC contaminated plant produced no fruits. It can be concluded from this study that poultry litter was able to remedy the effect of the spent engine oil pollution and enhance the growth and yield of maize (Zea mays). Therefore, effective management of polluted environment using poultry litter can help in enhancing microbial degradation of hydrocarbon product in the soil.