Authors :
Udube C.V; Njoku-Tony R.F; Ejiogu C.C
Volume/Issue :
Volume 7 - 2022, Issue 12 - December
Google Scholar :
https://bit.ly/3IIfn9N
Scribd :
https://bit.ly/3iKJ6rA
DOI :
https://doi.org/10.5281/zenodo.7547267
Abstract :
Soil contamination by hydrocarbons and trace
metals has led to adverse environmental and ecological
impacts globally. As with the case in most third-world
countries like Nigeria, where legal and illegal oil
refineries do not follow or implement the national policies
and guidelines for the treatment of industrial waste
products before these waste products are disposed of into
the environment. In this study, petroleum wastes
contaminated soil at Alesa, Eleme resulting from the
different production processes of petroleum products,
was investigated to know the extent of contamination by
heavy metals such as Iron (Fe), Zinc (Zn), Lead (Pb),
Sulphates (SO4), Phosphates (PO4) and organic
hydrocarbons like Phenols which are very dangerous to
the environment and how they can be remediated by
chemical and biological remediation methods and finding
out which method is more cost-effective and
environmentally friendly and sustainable. The extent of
contamination of the soil was determined by the collection
of soil samples from randomized sample points with
coordinates 290223.14N 527592.55E, 290260.98N
527694.41E and 290326.19N 527622.51E at the affected
area using a Standard Soil Auger at a depth of 15 – 30 cm
(subsoil), the soil was then pretreated and their
physiochemical properties were determined and later
analyzed for the presence of heavy metals under a
laboratory controlled experiment. High concentrations of
heavy metals and hydrocarbons were found to be present
in the soil from the affected area, this could also be seen
in a common dominant shrub locally known as stubborn
grass (Sida acuta) which was also analyzed for the
presence of heavy metals. Chemical remediation (using
EDTA/Oxalic acid) and biological remediation methods
(phytoremediation) using Sunflower (Helianthus annus)
were carried out to treat the contaminated soil and the
rate of removal of contaminants through
phytoremediation was calculated at 6 weeks and 9 weeks
intervals to know the extent to which the contaminants
were removed from the soil. The remediation methods
were proofed to be very effective. The results of one-way
analysis of variance of the contaminated soil at 6 weeks
and 9 weeks during the phytoremediation process were
3.014 and 49.2 respectively and this revealed that there
was a significant difference between the concentrations of
contaminants with an F value of 0.575 which is greater
than the F-Critical value for the alpha level selected
(0.05). It was recommended that the Government’s
Ministry of Environment at all levels, should adopt and
enforce sound waste management practices for refinery
wastes and phytoremediation should be considered in
reviving soil contaminated by refinery waste.
Keywords :
Heavy Metals, Contaminants, Remediation Methods, Phytoremediation
Soil contamination by hydrocarbons and trace
metals has led to adverse environmental and ecological
impacts globally. As with the case in most third-world
countries like Nigeria, where legal and illegal oil
refineries do not follow or implement the national policies
and guidelines for the treatment of industrial waste
products before these waste products are disposed of into
the environment. In this study, petroleum wastes
contaminated soil at Alesa, Eleme resulting from the
different production processes of petroleum products,
was investigated to know the extent of contamination by
heavy metals such as Iron (Fe), Zinc (Zn), Lead (Pb),
Sulphates (SO4), Phosphates (PO4) and organic
hydrocarbons like Phenols which are very dangerous to
the environment and how they can be remediated by
chemical and biological remediation methods and finding
out which method is more cost-effective and
environmentally friendly and sustainable. The extent of
contamination of the soil was determined by the collection
of soil samples from randomized sample points with
coordinates 290223.14N 527592.55E, 290260.98N
527694.41E and 290326.19N 527622.51E at the affected
area using a Standard Soil Auger at a depth of 15 – 30 cm
(subsoil), the soil was then pretreated and their
physiochemical properties were determined and later
analyzed for the presence of heavy metals under a
laboratory controlled experiment. High concentrations of
heavy metals and hydrocarbons were found to be present
in the soil from the affected area, this could also be seen
in a common dominant shrub locally known as stubborn
grass (Sida acuta) which was also analyzed for the
presence of heavy metals. Chemical remediation (using
EDTA/Oxalic acid) and biological remediation methods
(phytoremediation) using Sunflower (Helianthus annus)
were carried out to treat the contaminated soil and the
rate of removal of contaminants through
phytoremediation was calculated at 6 weeks and 9 weeks
intervals to know the extent to which the contaminants
were removed from the soil. The remediation methods
were proofed to be very effective. The results of one-way
analysis of variance of the contaminated soil at 6 weeks
and 9 weeks during the phytoremediation process were
3.014 and 49.2 respectively and this revealed that there
was a significant difference between the concentrations of
contaminants with an F value of 0.575 which is greater
than the F-Critical value for the alpha level selected
(0.05). It was recommended that the Government’s
Ministry of Environment at all levels, should adopt and
enforce sound waste management practices for refinery
wastes and phytoremediation should be considered in
reviving soil contaminated by refinery waste.
Keywords :
Heavy Metals, Contaminants, Remediation Methods, Phytoremediation
