CHAPTER ONEINTRODUCTION1.1 Background of the Study
Hydrocarbons are used in large quantities as fuels (Bierkens and Geerts, 2014). Hydrocarbons are becoming a global problem for the environment. They are highly persistent in the environment, toxic and present significant health risks to humans (Hentati et al., 2013).Hydrocarbons and other organic compounds can bring up serious environmental problems when spill occur (Zhang et al., 2010). Despite the economic benefits of hydrocarbon industry, hydrocarbons influences and alters soil microbial community composition and biogeochemical cycles, and triggers strongly negative impacts in sustainable soil fertility and environmental quality. The hydrocarbon pollutants enters into the soil, influences plant growth and causes human health concerns.Soil is a habitat for microorganisms and is the most bio diverse environment on earth (Tamames et al., 2010). Soil microorganisms are very important part of the environment ecosystems, which could adjust energy flow and cycle of matter by digesting animal, plant and oil residues, and plays a vital role in growth and development of agriculture crops, balancing of the soil ecosystem, organic matter transfer and bioremediation. Furthermore, the diversity of the microbial community in the soil is closely related to the function and structure of its surrounding ecosystem and is one of the components to maintain soil productivity. The present research in this field is mainly focused on functional diversity (Trivedi et al., 2012), species diversity (David et al., 2014), genetic diversity (Julia et al., 2014) and structural diversity (Thorsten et al., 2015). Hydrocarbon is very important to our economy. Its discovery as a source of energy has brought about high rate of civilization in our economy. It is one of the most important energetic resources in the world which is used as a raw material in numerous industries. It generates heat, making modern living possible especially in colder climates. It could also be used to make modern furniture like sofa, doors etc, it could also be used to fuel machines which makes life more comfortable.Hydrocarbon contamination on the coastal areas of different states in Nigeria has caused a lot destruction of flora, fauna and resort centers, pollution by drinking water as well as displacement of individuals, loss of lives and properties. When oil spilled onshore or near shore the soil and other components of the terrestrial ecosystem are inevitably affected in terrestrial environment, it can penetrate and spread on soil through topography nature of the soil environment. The soil as known is the main tool for agricultural productivity and socio-economic activities and so any threat to the soil usually affects the people’s livelihood and results into public outcry (Adewole and Moyinoluwa, 2012).It is important for hydrocarbon contamination to be remediated. This effect can be remedied by bioremediation using compost; microorganisms present in compost are utilized under some specified conditions to remedy the negative effects in cost-effective and environmentally friendly approach of all methods (chemical, physical, biological) of remediating crude oil contaminated land, biological methods is the most effective and consequence free. The hydrocarbonclastic microorganisms are the main tool used in biological methods to remove hydrocarbon from contaminated surfaces. Soil enzymatic have a central role in soil environment and are used as attractive bio-indicators for monitoring various impact on the soil e.g. Dehydrogenases are enzymes that catalyze the removal of hydrogen atom from substrates (Nelson and COX lehninger, 2000). Catalase are iron porphyryin and oxidant enzymes that catalyses very rapid decomposition of hydrogen peroxide to water and oxygen. Both catalase and hydrogenase are used as biomarkers for microbial activities in the soil as they are very sensitive to pollution by hydrocarbon.