ABSTRACT

 Crude oil pollution is one of the commonest environmental pollution plaguing the Niger Delta in
Nigeria due to transportation, accidental discharge and spillage. This study aimed to ascertain the changes in
physicochemical properties and heavy metals level of crude oil polluted soil propagated using randomized block design
and measured by standard methods. The physicochemical properties of the soil before and after the end of the
experiment were 0.89% (MC), 0.30% (N). 96.25ppm (P), 1.33meq/mg (K) and 1.62% (OC) as compared to 0.16%
(MC), 0.27% (N), 6.00 ppm (P), 0.72 meq/mg (K) and 1.84% (OC) in control. The soil was maintained its alkaline
status of 6.00 – 6.50. There was an increase in Cu, Fe and Mn in HI from 3.33 to 3.44 and 3.42 ppm, 108.99 to 138.67
and 139.05 ppm, and 147.21 to 169.97 and 170.23 ppm respectively. However, there was an increase in Zn and Pb
content of HI from 94.44 to 73.93 and 74.02 ppm, and 42.10 to 27.80 and 25.45 ppm respectively of the C. annum and
C. frutescens. In conclusion, crude oil affects soil properties irrespective of season by precipitating a hydrophobic layer
thus creating a competitive interaction between heavy metals and essential nutrients.