1.0 Introduction
1.1 Background of Study
In the early studies, attention was given to the general toxicological effects of petroleum hydrocarbons on fish, leading to significant findings regarding the mortality rates, reproductive success, and behavioural changes in different fish species (Khan et al., 2009). Specifically, Clarias gariepinus, a species widely consumed in Africa and known for its resilience, became a focal point for investigating the effects of these contaminants. Research revealed that exposure to petroleum by-products could lead to alterations in blood parameters, including haemoglobin levels, which are critical indicators of health and stress in fish (Omoregie et al., 2017). The 1980s and 1990s marked a significant period for environmental research in Nigeria, particularly in the Niger Delta region, where oil spills were prevalent. Studies began to focus on the specific impacts of these spills on local fish populations and their habitats (Ofoegbu & Olatunde, 1990). During this time, researchers documented the toxic effects of kerosene and other petroleum derivatives on aquatic ecosystems, noting that these pollutants led to decreased oxygen transport capacity in fish due to changes in haemoglobin concentration (Obi et al., 2005).
Over the years, various studies have highlighted the importance of understanding the physiological responses of Clarias gariepinus to petroleum pollution, particularly in the context of its growing role in aquaculture and food security (Adeyemo, 2016; Akhigbe et al., 2018). Researchers have sought to establish a clearer relationship between petroleum exposure and its effects on haematological parameters, aiming to inform better management practices and policies for preserving freshwater resources.
As the world becomes increasingly aware of the implications of environmental degradation, the study of the effects of petroleum by-products on aquatic organisms continues to be critical. The ongoing research into how such pollutants affect the haemoglobin levels of Clarias gariepinus is crucial for ensuring the sustainability of this species and protecting the broader ecosystem from the deleterious effects of pollution.
The effect of petroleum by-products, specifically fuel and kerosene, on aquatic life has garnered significant attention due to the rising incidence of oil pollution in marine and freshwater ecosystems. Among the species affected, the African catfish (Clarias gariepinus) is of particular importance due to its economic value and ecological significance in African freshwater systems. Oil spills and the discharge of petroleum products into water bodies have been linked to various detrimental effects on fish health, including alterations in physiological parameters such as haemoglobin levels (Saliu et al., 2019). Haemoglobin plays a critical role in oxygen transport and is a key indicator of the health and vitality of fish. Exposure to petroleum by-products can disrupt normal physiological functions, leading to impaired respiratory capacity and overall fitness (Adeyemo, 2016). The toxic compounds present in fuel and kerosene may cause oxidative stress, leading to hematological alterations, which can compromise the survival and reproduction of aquatic organisms (Omoregie et al., 2017).
The African catfish (Clarias gariepinus) is a widely recognized fish species in Africa, known for its adaptability to various aquatic environments and its significance in aquaculture and local fisheries. This species is not only a vital source of protein for millions but also plays an essential role in the ecosystem by participating in nutrient cycling and serving as a food source for larger predators (Nduka et al., 2017). However, the health and sustainability of catfish populations are increasingly threatened by environmental pollutants, particularly petroleum by-products such as fuel and kerosene.
The release of these petroleum products into freshwater bodies is primarily attributed to human activities, including industrial discharges, oil spills, and improper waste disposal. The resulting contamination poses a severe risk to aquatic organisms, leading to toxicological effects that can disrupt physiological functions and threaten biodiversity (Akhigbe et al., 2018). Exposure to hydrocarbons from petroleum can lead to various adverse effects on fish, including changes in behaviour, growth, reproduction, and crucially, their haematological parameters (Omoregie et al., 2017). Haemoglobin, a protein responsible for oxygen transport in the blood, is an essential indicator of fish health. Alterations in haemoglobin levels can signify physiological stress and impairment, which can arise from exposure to toxic substances such as those found in petroleum products (Adeyemo, 2016). Changes in haemoglobin concentration can impact the fish's overall fitness, growth rate, and ability to cope with environmental stressors, ultimately affecting survival and reproductive success (Akan et al., 2015).
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the effect of petroleum by-products (fuel and kerosene) on the haemoglobin of african cat fish (clarias gariepinus).
1.2 Statement of Problems
Investigation revealed that the effect of petroleum by-products, particularly fuel and kerosene, on the haemoglobin levels of African catfish (Clarias gariepinus) is a critical concern due to the increasing incidence of oil spills and pollution in aquatic environments. The exposure of aquatic organisms to these toxic substances is associated with various physiological alterations, particularly in the blood parameters that are essential for the health and survival of fish (Omoregie et al., 2017). Research indicates that petroleum contaminants disrupt the normal functioning of fish, leading to reduced haemoglobin concentrations, which in turn affects oxygen transport and overall metabolic processes (Akhigbe et al., 2018).
The Niger Delta region of Nigeria, known for its rich oil reserves, has been significantly impacted by petroleum exploitation, resulting in frequent oil spills that contaminate freshwater bodies and pose serious threats to aquatic life (Obi et al., 2005). This situation raises the urgent need to investigate how petroleum by-products affect the haemoglobin levels in Clarias gariepinus, a species of great economic importance and ecological value. Moreover, the lack of comprehensive studies addressing the specific effects of different concentrations of fuel and kerosene on the haemoglobin levels of this species presents a substantial knowledge gap.
1.3 Aim and Objectives of Study
The aim of the study is to investigate the effect of petroleum by-products (fuel and kerosene) on the haemoglobin of african cat fish (clarias gariepinus). In achieving this aim, the following specific objectives were laid out as follows:
- To determine the haemoglobin levels in Clarias gariepinus before and after exposure to different concentrations of fuel and kerosene.
- To evaluate the comparative effects of fuel and kerosene on the haemoglobin levels in Clarias gariepinus.
- To assess the potential health risks posed to Clarias gariepinus as a result of exposure to petroleum by-products.
- To provide insights that could guide environmental management and policies aimed at mitigating the impact of petroleum pollution on aquatic life.
1.4 Research Questions
The study came up with research questions so as to be able to ascertain the above stated objectives. The specific research questions for the study are stated below as follows:
- What is the baseline haemoglobin level in Clarias gariepinus before exposure to petroleum by-products?
- How does exposure to varying concentrations of fuel and kerosene affect the haemoglobin levels of Clarias gariepinus?
- Is there a significant difference in the effect of fuel and kerosene on the haemoglobin levels of Clarias gariepinus?
- What are the potential physiological impacts of petroleum by-products on the overall health of Clarias gariepinus?
- How could the findings contribute to understanding the environmental risks of petroleum contamination in aquatic ecosystems?
1.5 Research Hypothesis
In order to pursue the objective of this study, the following generalized statements have been designed to guide and aids in obtaining the result for the experiment to be conducted. For this work, the null hypothesis will be represented with H0 while the alternative hypothesis will be represented with hypothesis H1.
- H01: There is no significant effect of petroleum by-products (fuel and kerosene) on the haemoglobin levels of African catfish (Clarias gariepinus).
- H02: Petroleum by-products (fuel and kerosene) significantly affect the haemoglobin levels of African catfish (Clarias gariepinus).
1.6 Significance of Study
The study will provide insight into how petroleum by-products impact aquatic life, helping environmental policymakers make informed decisions to protect water ecosystems. It will also guide fish farmers on potential risks associated with fuel and kerosene contamination, ensuring better fish health management.
Additionally, the research study will benefit environmental scientists by expanding knowledge on the toxicological effects of petroleum by-products on aquatic species, particularly African catfish.
Furthermore, it will support regulatory bodies in establishing safety limits for petroleum contamination in aquatic environments to protect public health and food security. Also, it will raise awareness among the general public and fuel industry stakeholders about the environmental and health implications of improper petroleum disposal.
1.7 Scope of the Study
The scope of the research is focused on the effect of petroleum by-products (fuel and kerosene) on the haemoglobin of african cat fish (clarias gariepinus).
1.8 Limitations of the Study
During the course of this study, many things militated against its completion, some of which are:
- Frequent power failures during the experiment led to disruptions in data collection and analysis, affecting the overall reliability of the results.
- Financial constraints restricted the ability to conduct extensive sampling and replicate experiments, which was essential for validating findings.
- Time constraints affected the thoroughness of the study, resulting in a reduced ability to explore additional variables that could influence the haemoglobin levels in African catfish.
1.9 Definition of Terms
Petroleum By-Products: These are substances derived from the processing of crude oil, including fuels like gasoline and kerosene, which are commonly used in transportation and heating. They are known to have toxic effects on aquatic organisms when released into water bodies (Tchounwou et al., 2012).
Fuel: Refers to liquid hydrocarbons derived from petroleum that are used to produce energy for transportation, heating, and electricity generation. Fuels can contaminate water bodies through spills and improper disposal, posing significant risks to aquatic life (Sharma et al., 2020).
Kerosene: A specific type of liquid hydrocarbon fuel obtained from the distillation of crude oil. Kerosene is often used for heating and as a fuel for jet engines, and its presence in aquatic ecosystems can adversely affect the health of fish and other organisms due to its toxic properties (Udo et al., 2020).
Haemoglobin: A protein in red blood cells responsible for transporting oxygen throughout the body. In fish, the level of haemoglobin is an important indicator of health and can be affected by environmental stressors, including pollution from petroleum products (Mansoori et al., 2018).
Clarias gariepinus: Commonly known as the African catfish, this species is widely cultivated for food and has a significant role in aquaculture. Its sensitivity to environmental changes, including pollution, makes it an important indicator species for studying the effects of contaminants in aquatic ecosystems (Bako et al., 2021).
Toxicity: Refers to the degree to which a substance can harm living organisms. The toxicity of petroleum by-products varies based on concentration, exposure duration, and the sensitivity of the affected species, making it a crucial factor in assessing environmental impacts (Nduka et al., 2022).
