Abstract:
The earthworm Eisenia Fetida bioremediation capacity in soil contaminated with
crude oil was examined. 3 ml and 6 ml crude oil, each with repetitions, were contaminated
with dried and sieved soils, inoculated with earthworms, and monitored daily for 14 days.
Standard methods were used to determine physicochemical parameters such as pH,
Electrical Conductivity (EC), sulphate, nitrate, phosphate and potassium. GC-MS was
used to determine total petroleum hydrocarbon (TPH), BTEX contents in soil and
earthworm’s tissues. The results indicates that the earthworm decreased the
physicochemical parameters of the contaminated soil except pH (6.5) that slightly
increased. Primary nutrient of soil, sulfate (52.60 %), nitrate (50.29 %), phosphate (54.26
%), potassium (57.68 %) decreased at the end of experiment. There was a significant
decrease in the TPH (84.99 %), benzene (92.55 %), toluene (99.99 %), ethylbenzene
(99.99 %) and xylene (99.99 %). Analyses of the tissues of the earthworm at the end of
the experiment showed that the earthworms bioaccumulated/biodegraded 56.33/26.64 %
TPH, 37.91/52.73 % benzene, 24.77/71.14 % toluene, 41.27/56.74 % ethylbenzene and
07.22/91.35 % xylene. It was observed that TPH concentration of 3ml was not harmful
for the survival of earthworms but the TPH concentration of 6ml reduced their survival
to 40%. The finding of the study showed that the earthworm (Eisenia Fetida) could be
used in the remediation of crude oil contaminated soil.
