CHAPTER ONE
1.0 INTRODUCTION
Crude oil is physically, chemically and biologically harmful to soil because it contains
many toxic compounds in relatively high concentrations (Franco et al., 2004). Soil
contamination can result in soil degradation, bring great loss to agricultural production and pose
threat to human health (Lijuan, 2012). Crude oil spill is a common event in Nigeria especially in
the Niger Delta areas of the country. Spills may arise from oil well drilling, production
operations, transportation, refining, storage and marketing. It could also be from anthropogenic
sources such as sabotage or accidental spills such as ruptured oil pipelines (Oberdorster and
Cheek, 2000). Presently there are eleven oil corporations operating about 159 oil wells in Niger
Delta region of Nigeria. Record indicates that the Niger Delta region of Nigeria experiences on
the average, 273 oil spills resulting to about 115,000 barrels of crude oil annually from 1983-
2005 making the region most vulnerable to oil spill than anywhere in the world (Agbogidi et al.,
2009). Some recent oil spill in Nigeria include Assa-Rumekpe pipeline at Elele Alumini in 2014,
Amukpe trunk line at Amukpe in 2011, Nkpoku Bomu pipeline at Ekporo in 2014, Nun-river
Kolo creek at Oporoma in 2013 (SPDC, 2014). Oil spillage has immense impact on the
ecosystem into which it is released. Contamination of soil arising from oil spills is one of the
most limiting factors to soil fertility (Onwurah et al., 2007).
It affects growth of plants
(Nwadinigwe and Onwumere, 2003) and causes great negative impacts on food productivity
(Onwurah et al., 2007). The work of Nwadinigwe and Uzodimma (2005) indicated the inhibitory
effect of crude oil on the germination, growth and reproductive performance of Arachis
hypogaea. Germination, growth and pod production of Glycine max have also been found to be
inhibited by crude oil pollution (Nwadinigwe and Onwumere, 2003). Yellowing, dropping of
xii
leaves and complete shedding of leaves in areas of heavy pollution have been reported by
Opeolu (2000). Environmental cleanup of crude oil can take several years (Short et al., 2002)
and problems associated with the study and remediation of the polluted ecosystem can be very
expensive. The legal problems related to compensation in terms of assigning monetary reward
may bring serious controversy. Nigerian regulation of the oil industry is weak and rarely
enforced, allowing in essence the industry to self-regulate. The ecosystem especially the
agricultural sectors are very much prone to the adverse effects of oil pollution, since there has
been no concerned and effective effort on the part of the government, let alone the oil operators,
to control this environmental problem. Yet, there is still an extensive network of pipelines
between the fields as well as numerous small networks of flow lines in the oil fields such as in
the Niger Delta area, allowing more oil spill (Anderson, 2005).
1.1 RELEVANCE OF MICROORGANISMS IN THE SOIL
Microorganisms are important for soil quality and fertility. They play a major role in
decomposition of organic matter, degradation of chemical pollutants and mineralization in the
soil (Brussard, 1994). Amongst the different microorganisms inhabiting the soil, bacteria are the
most abundant and predominant organisms (Hirsch, 1996). Bacteria and other microbes are
chemical processors, tiny biotechnologists, capable of catalyzing thousands of chemical reactions
that higher organisms are incapable of mediating. It has been reported that bacteria constitute the
principal agents of hydrocarbon biodegradation (Jensen, 1975). It is well known that soil microflora
and fauna can be manipulated indirectly through crop management practices. Similarly,
cultivation of legumes leads to increased number of their compatible rhizobia (Hirsch, 1996).
1.2 DELONIX REGIA HOOK.
1.0 INTRODUCTION
Crude oil is physically, chemically and biologically harmful to soil because it contains
many toxic compounds in relatively high concentrations (Franco et al., 2004). Soil
contamination can result in soil degradation, bring great loss to agricultural production and pose
threat to human health (Lijuan, 2012). Crude oil spill is a common event in Nigeria especially in
the Niger Delta areas of the country. Spills may arise from oil well drilling, production
operations, transportation, refining, storage and marketing. It could also be from anthropogenic
sources such as sabotage or accidental spills such as ruptured oil pipelines (Oberdorster and
Cheek, 2000). Presently there are eleven oil corporations operating about 159 oil wells in Niger
Delta region of Nigeria. Record indicates that the Niger Delta region of Nigeria experiences on
the average, 273 oil spills resulting to about 115,000 barrels of crude oil annually from 1983-
2005 making the region most vulnerable to oil spill than anywhere in the world (Agbogidi et al.,
2009). Some recent oil spill in Nigeria include Assa-Rumekpe pipeline at Elele Alumini in 2014,
Amukpe trunk line at Amukpe in 2011, Nkpoku Bomu pipeline at Ekporo in 2014, Nun-river
Kolo creek at Oporoma in 2013 (SPDC, 2014). Oil spillage has immense impact on the
ecosystem into which it is released. Contamination of soil arising from oil spills is one of the
most limiting factors to soil fertility (Onwurah et al., 2007).
It affects growth of plants
(Nwadinigwe and Onwumere, 2003) and causes great negative impacts on food productivity
(Onwurah et al., 2007). The work of Nwadinigwe and Uzodimma (2005) indicated the inhibitory
effect of crude oil on the germination, growth and reproductive performance of Arachis
hypogaea. Germination, growth and pod production of Glycine max have also been found to be
inhibited by crude oil pollution (Nwadinigwe and Onwumere, 2003). Yellowing, dropping of
xii
leaves and complete shedding of leaves in areas of heavy pollution have been reported by
Opeolu (2000). Environmental cleanup of crude oil can take several years (Short et al., 2002)
and problems associated with the study and remediation of the polluted ecosystem can be very
expensive. The legal problems related to compensation in terms of assigning monetary reward
may bring serious controversy. Nigerian regulation of the oil industry is weak and rarely
enforced, allowing in essence the industry to self-regulate. The ecosystem especially the
agricultural sectors are very much prone to the adverse effects of oil pollution, since there has
been no concerned and effective effort on the part of the government, let alone the oil operators,
to control this environmental problem. Yet, there is still an extensive network of pipelines
between the fields as well as numerous small networks of flow lines in the oil fields such as in
the Niger Delta area, allowing more oil spill (Anderson, 2005).
1.1 RELEVANCE OF MICROORGANISMS IN THE SOIL
Microorganisms are important for soil quality and fertility. They play a major role in
decomposition of organic matter, degradation of chemical pollutants and mineralization in the
soil (Brussard, 1994). Amongst the different microorganisms inhabiting the soil, bacteria are the
most abundant and predominant organisms (Hirsch, 1996). Bacteria and other microbes are
chemical processors, tiny biotechnologists, capable of catalyzing thousands of chemical reactions
that higher organisms are incapable of mediating. It has been reported that bacteria constitute the
principal agents of hydrocarbon biodegradation (Jensen, 1975). It is well known that soil microflora
and fauna can be manipulated indirectly through crop management practices. Similarly,
cultivation of legumes leads to increased number of their compatible rhizobia (Hirsch, 1996).
1.2 DELONIX REGIA HOOK.
