An ecological study was carried out to evaluate remediation potential of three
hydrocarbon tolerant species (
Peltophorum pterocarpum
(DC.) Heyne,
Leucaena leucocephala
(Lam.) De Wit., and
Crotolaria retusa
Linn) of Fabaceae plant family in relation to enzyme
activity for cleaning up soils contaminated with waste oil hydrocarbon. Biochemical analyses
were carried out using classical standard procedures to assess the level of enzyme expression in
relation to hydrocarbon index assessment in remediation performance through a holistic test of
significance using the PROC ANOVA and Duncan’s New Multiple Range Test (DNMRT)
procedures. Enzyme expression, oil removal and organic carbon sequestration of the species and
the species treated soils showed that in pre-polluted soil foliar enzyme expression in the order
Cr>Ll>Pp was high but reduction in post-polluted and post-phytoremediation soils in the order
Cr>Ll>Pp. Generally, among species
Peroxidase (POD) was higher in activity and expression
than
Polyphenoloxidase (PPO). The oil and grease recorded a lower content in the pre-pollution
soil which increased in content in post-pollution with increase in pollution. However, the impact
of phytoapplication has shown some significant (p<0.05) reduction in
L. leucocephala soil in the
order
Ll but higher foliar content among the species in the order Ll>Pp>Cr at low
enzyme expression in which P. pterocarpum had higher carbon content in the order Pp>Cr> Ll.
The pre-pollution soil had a significantly lower carbon than post-polluted soils. The impact of
phytoremediation has shown reduction in carbon content with P. pterocarpum treated soil
significantly lower in content in the order Pp and higher foliar content in the order
Pp>Cr> Ll. Thus by the forgoing trajectories and trend of indigenous enzymes, P. pterocarpum
and L. leucocephala can thus be recommended as an integral component in any bioremediation
technology package for waste oil polluted terrestrial environment.© JASEM
