Abstract

Beckley IKHAJIAGBE1* and Geoffery Obinna ANOLIEFO2

The effect of natural attenuation on bioremediation of waste engine oil (WEO) polluted soil was investigated. Soil was polluted with WEO at the rate of 0, 1.0, 2.5, 5.0 and 10.0% w/w oil in soil. The entire set up was left in the open shade for 5 months after pollution (5 MAP) in the first instance, and then for another 9 months (14 MAP), without mechanically disturbing the soil. Soil was carefully irrigated with 200 ml of water twice every week. There was significant reduction in heavy metal concentration of soil as well as total hydrocarbon contents. Total polycyclic aromatic hydrocarbon (PAH) content of soil reduced from 36.95 to 25.45 ppm in the control compared to 538.59 to 456.99 ppm in 10.0% w/w oil in soil. There was total eradication of chrysene, fluoranthene, fluorine and indeno(1,2,3- c,d)pyrene in all levels. Environmental risk factor initially posed by the presence of heavy metals in the soil at 5 MAP was significantly reduced to safe levels at 14 MAP.