ASSESSMENT OF THE TOXICITY PROFILE OF CRUDE OIL UTILIZING MICROORGANISM IN SEDIMENT AT EASTERN- OBOLO L.G.A

CHAPTER ONE
1.0 Introduction
Oil products are continually used as a main source of energy in industry and daily life (Kvenolden and Cooper 2003). Release of hydrocarbons into the environment, whether accidentally or due to anthropogenic activities, is a major cause of water and soil contamination (Holliger et al., 1997). As dependency to oil is increasing, the allied problems are becoming more and more cumbersome (Mortal and Singh, 2009). Soils which are contaminated by hydrocarbons expose an extensive damage to local ecosystems as accumulation of pollutants in animals and plants tissues can cause death or mutation (Alvarez and Vogel, 1991). We need to prevent from expansion of contamination and also clean up the contaminated areas. Various methods, including bioremediation, can be used for this purpose (Kristanti et al., 2011). The ability of microorganisms to utilize hydrocarbons in oil-contaminated environments has been documented. (Adekunle and Adebambo, 2007; Atlas 1981; Ashraf and Ali, 2006). Several fungi have been found to exhibit greater hydrocarbon biodegradability than bacteria (Cemiglia and Perry, 1973). The advantages associated with fungal bioremediation lay primarily in versatility of the technology and its cost efficiency as compared to other remediation technologies such as incineration, thermal desorption and extraction. (George-Okafor 2009). The use of fungi is expected to be relatively economical as they can be grown on a number of inexpensive agricultural or forest wastes such as corncobs and sawdust. Moreover, their utilization is a gentle non-aggressive approach. Species of many fugal genera are known to metabolize hydrocarbons and thrive in oil-contaminated sites and the most common fungi which have been recorded as biodegraders belong to the genera: Alternaria, Amorphoteca, Aspergillus, Candida, Cephalosporium, Cladosporium, Fusarium, Geotrichum, Graphium, Mucor, Paecilomyces, Penicillium, Rhizopus, Rhodotorula, Sphaeropsidales, Talaromyces and Trichoderma. (Dawoodi and Madani, 2015).
Niger Delta Region of Nigeria is one of the top countries in the world with huge oil and gas reserve. The exploration of this crude resource gives rise to hydrocarbon pollution through routine oil operation, vehicular accident and illegal petroleum refining activities. The latter is currently the leading source of oil pollution in the region and the likelihood of putting a stop to this act is very slim because of the economic benefits enjoyed by the perpetrators and their collaborators. The hydrocarbon wastes emanating from these refineries are of high molecular weight including polyaromatic hydrocarbons (PAHs). The eco-toxicological impacts already in manifestation include air borne black soot, changes in soil physicochemical features, depletion in biodiversity, ground water contamination, bioaccumulation in environmental receptors and cancer related diseases and deaths. (Kalantary. et al. 2014). Polyaromatic hydrocarbons (PAHs) are a group of organic pollutants that consist of two or more aromatic rings arranged in different configurations (Yu KSH et al.2005). They are ubiquitous (Chikere and Chijioke 2006), persistent due to their inert nature (Isaac et al.2013), and are highly insoluble in water (Nganje et al.,2014). According to Kumar et al. (Kumar et al.,2011). there are not less than 30 parent PAHs in crude oil out of which sixteen (16) have been considered as priority pollutants by the United State Environmental Protection Agency (US EPA), World Health Organisation (WHO,…) and European Union (UN,…) (Zrafi-Nouira et al.,2012), due to their mutagenic, carcinogenic and teratogenic nature. Remediation of these contaminants is necessary for environmental safety, sustainable development and human health. The mechanistic principles of PAHs’ remediation are physical, chemical and biological methods. (Tomei and Daugulis, 2013). Physical and chemical methods are preferred to biological method when exigency calls, however they are capital intensive and require high energy with huge consumption of synthetic chemicals which may pose additional environmental challenge (Mrozik and Piotrowska, 2010). These other reasons such as simplicity of technology, minimal site disruption, flexibility to be combined with other physicochemical methods (treatment train) of remediation are reasons bioremediation has become an attractive technology these days. The most critical advantage is that the biodegradation agents are hugely unlimited, renewable, versatile, flexible and ubiquitous. (Kumar et al.,2013). Bacteria stand out to be the most resourceful organisms when it comes to bioremediation. Bacteria can survive anaerobic and prohibitive environments such as acid mines, heavy metal and radioactive dumps. Bacterial adaptive physiological and degradative.
1.1 STATEMENT OF PROBLEMS
Different oils and petroleum-related products have different levels of toxicity. Levels of toxicity are influenced by many factors such as weathering, solubility, as well as chemical properties such as persistence. Increased weathering tends to decrease levels of toxicity as more soluble and lower molecular weight substances are removed. Highly soluble substances tend to have higher levels of toxicity than substances that are not very soluble in water. Generally, oils that have longer carbon chains and with more benzene rings have higher levels of toxicity. Benzene is the petroleum-related product with the highest level of toxicity. Other substances other than benzene which are highly toxic are toluene, methylbenzene and xylenes
1.2 JUSTIFICATION
The present study aimed at providing an insight to an effective strategy to an environmentally friendly and cost-effective means of environmental bioremediation of accidentally released petroleum oil and hence provide a possible effective oil spill response management strategy to oil prospecting, refining and transporting companies.
1.3 AIM OF STUDY
This study is aimed at assessing the toxicity profile of crude oil utilizing microorganism in sediment at Eastern- Obolo L.G.A – AKS
1.4 RESEARCH OBJECTIVES
To determine the total heterotrophic aerobic bacteria from the sediment samples
To isolate hydrocarbon utilizing bacteria/fungi (HUB/HUF)
To characterize and identify the HUB/HUF