The post crude oil spill impact assessment of Omoku soils, four years after oil-pipeline leakage,
was carried out, using soil samples obtained at two core depths of 0-15 cm and 15-30 cm, for the
gas chromatographic determination of the total hydrocarbon content (THC). Cassava tuber
samples harvested from crude oil impacted soils were used for the proximate analysis by the
methods of Association of Official Analytical Chemists. All the surface soils from the sampled
plots (quadrats) had higher THC than the control (15.58±0.16mg/kg), while the sub-surface soils
from the sampled plots except quadrat 21 (20.56±0.23mg/kg) had higher THC relative to the
control (with 39.48±0.24mg/kg). Proximate analysis showed that the cassava tubers grown on
the crude-oil impacted soil contained 63.95±3.40% moisture; 0.58±0.10% ash; 0.44±0.05%
crude protein; 1.20±0.05% crude lipid; 1.56±0.12% crude fibre; 32.27±1.30% total
carbohydrate; and calorific value of 141.64 Kcal/100g sample. Comparative proximate analyses
of the cassava tubers harvested from oil-spilled soils over those from the non-oil-spilled soils
revealed increases in moisture content (4.91%), ash (13.8%), lipid (74.2%), fibre (9.62%) and
decreases in protein content (68.2%), total carbohydrate (12.3%) and calorific value (6.38%).
These indicate that the oil impacted soils had not been fully rehabilitated at the time of sampling.