1.1 Introduction
Crude oil pollution is the uncontrolled release of toxic chemicals caused by equipment failure, operation mishaps, human error or intentional damage to facilities. The extent of damage depends on what, when and how much has been spilled and how long it remains in the immediate and impacted environment. Pollution is defined as the release of toxic or harmful substances into the environment (air, water and land) by their natural forces or man and other animals to an extent that cause biological damage to man and his resources. The harmful substances that cause pollution to the environment are called pollutants (Eshagberi, 2014).
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
Crude oil is one of the poisonous chemicals in water bodies. Crude oil also known as petroleum is a dark brown liquid, mixed with gases and solids in oil wells. It is believed that it was formed by bacterial decomposition of animal and plant remains over a long period of time (Ogali, 2009). Crude oil pollution is the uncontrolled release of toxic chemicals caused by equipment failure, operation mishaps, human error or intentional damage to facilities. The extent of damage depends on what, when and how much has been spilled and how long it remains in the immediate and impacted environment. In the case of aquatic environment, the impacts are in the range of unquantifiable damages on fishes and other economically important aquatic organisms, as well as the direct and indirect negative effects on the socio-economic lives of human settlers whose survival has much to do with the products of aquatic ecosystem (SPDC, 1997). Apart from uncontrolled oil spills, production operations inevitably release effluent in form of produced waters, storm waters and flushing wastes into the aquatic environment and these are found to contain significant quantities of hydrocarbons and associated pollutants(SEEMS, 1997). Dissolved oxygen refers to the free, non-compound oxygen present in water. Oxygen enters water by direct absorption from the atmosphere which is enhanced by turbulence. Water also absorbs oxygen released by aquatic plants during photosynthesis. Dissolved oxygen is an important parameter in assessing water quality because of its influence on the organisms living within a body of water. A dissolved oxygen level that is too high or too low can harm aquatic life and affect water quality (Kemker, 2013). pH of a solution is simply the negative logarithm of hydrogen ion concentration. The pH of a solution describes the acidity of that solution. Acidic solutions are those with a pH of less than 7 and basic solutions have a pH greater than 7. The normal pH of pure water is 7 which is neutral. In aquatic ecosystem, the pH of water varies depending on the type of organism in a particular habitat. Living organisms in water are highly sensitive to pH changes. Too high or too low pH will affect the lives and activities of plants and animals in water. Plants and animals are adapted to special pH values. pH of freshwater is low while marine pH is high (Eshagberi, 2014).
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to identify the Effect of Crude Oil Pollution on Dissolved Oxygen and PH in Aquatic Ecosystem.
1.3 Statement of Problems
The magnitude of crude oil pollution and damage occasioned by human activities is incredible. Crude oil or petroleum became a richly available commodity of essence about a century ago. The now widespread use of this black gold cannot be over emphasized. It is noteworthy that, the environment with its eventual hazards on both aquatic and terrestrial ecosystem contributes to an irreversible chain effect on both the biodiversity and human safety. Crude oil pollution has a wide range effect on aquatic organisms as to the whole aquatic ecosystem. The effect of crude oil pollution faced with aquatic ecosystem is fluctuations in pH and dissolved oxygen level which affect the survival rate of the aquatic organisms.
1.4 Aim and Objectives of Study
The aim of the study is to examine the Effect of Crude Oil Pollution on Dissolved Oxygen and PH in Aquatic Ecosystem. In achieving this aim, the following specific objectives were laid out as follows:
- To determine the effect of water extract of crude oil on the Aquatic Ecosystem
- To determine the effect of water extract of crude oil on dissolved oxygen of Aquatic Ecosystem
- To assess the effect of water extract of crude oil on pH of aquatic ecosystem.
1.5 Significance of Study
The significance of this study is to provide an up-to-date knowledge of the effect of crude oil pollution on dissolved oxygen and pH in aquatic ecosystem. This study is therefore carried out to know the causes of crude oil pollution in aquatic ecosystem and the effect it has on dissolved oxygen and pH and if possible, provide solution to these effects.
It is also hoped that the study will provide a sound knowledge about the standard value of dissolved oxygen and pH concentrations and how deviations from the standard value affect aquatic organisms and how the deviations can be controlled.
1.6 Scope of the Study
The study focuses on the Effect of Crude Oil Pollution on Dissolved Oxygen and PH in Aquatic Ecosystem in Owerri-west Local Government Area in Imo state, Nigeria.
1.7 Limitations of the Study
During the course of this study, many things militated against its completion, some of which are:
- Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
- Research material: availability of research material is a major setback to the scope of the study.
- Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
- Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet, questionnaire and interview).
1.8 Definition of Terms
The following terms are used in this research work. For a clear understanding, the following definitions have been given.
Toxic: A substance is said to be toxic when it contains poison.
Pollutants: Pollutants can be defined as substance present in greater than normal concentration as a result of human activities that has a net detrimental effect upon the environment.
Contaminants: Contaminants can be defined as substance present in the environment without any foreseeable harmful effect.
Ecosystem: This can be defined as the community of plants and animals interacting with themselves and their external environment and forms a functional unit.
Sewage: Sewage can be defined as liquid waste from domestic sources, industrial sources, and agricultural sources.
Concentration: Concentration can be defined as weight of solute per weight of solvent or as number of moles of solute per number of moles of solvent.
