Evaluation of Antioxidant Enzyme Activities in Populations Exposed to Air Pollution in Lagos Metropolis

Evaluation of Antioxidant Enzyme Activities in Populations Exposed to Air Pollution in Lagos Metropolis

Abstract

Air pollution remains a major environmental health problem, particularly in rapidly growing cities such as Lagos, Nigeria. Continuous exposure to airborne pollutants induces oxidative stress in humans, leading to biochemical alterations that compromise normal cellular function. This study evaluates the activities of key antioxidant enzymes—superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)—in individuals living in different parts of Lagos with varying levels of air pollution.

Blood samples were collected from participants residing in high-traffic and low-traffic areas. Enzyme activities were measured spectrophotometrically and compared between groups. Results revealed a significant reduction in antioxidant enzyme activities among individuals exposed to heavy air pollution compared to those in cleaner environments. This finding suggests that persistent exposure to airborne contaminants such as particulate matter, carbon monoxide, and nitrogen oxides triggers oxidative damage that overwhelms the body’s defense mechanisms.

The study highlights the urgent need for improved air quality control and public awareness about pollution-related health risks. It also recommends routine biochemical screening for individuals living in high-pollution zones to detect early signs of oxidative stress. Overall, these findings emphasize the critical relationship between environmental exposure and biochemical health.

CHAPTER ONE

1.0 Introduction

Air pollution has emerged as one of the most pressing global environmental challenges. It poses severe risks not only to the ecosystem but also to human health. In metropolitan cities such as Lagos, the increasing rate of industrialization, vehicular emissions, and poor waste management has significantly degraded air quality. Continuous exposure to polluted air introduces reactive oxygen species (ROS) into the human body, leading to oxidative stress—a condition where the production of free radicals exceeds the capacity of antioxidant defenses.

Oxidative stress damages biological macromolecules such as lipids, proteins, and DNA. However, the human body combats these effects through antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). These enzymes play a crucial role in detoxifying reactive oxygen species and maintaining cellular balance. Therefore, monitoring their activity in populations exposed to air pollution provides valuable insight into the body’s biochemical response to environmental stress.

In Lagos metropolis, constant traffic congestion and industrial activities contribute heavily to poor air quality. Residents in densely populated areas are frequently exposed to pollutants that can cause respiratory illnesses, cardiovascular problems, and long-term oxidative damage. Understanding how such exposure influences antioxidant enzyme levels will help in assessing public health risks and formulating preventive strategies.

1.1 Background of the Study

Air pollution consists of complex mixtures of gases and particulate matter that originate from vehicles, industries, and domestic sources. The pollutants interact with human tissues, generating reactive oxygen species capable of inducing oxidative stress. The body’s natural antioxidant defense system neutralizes these radicals, but excessive exposure may overwhelm it.

Several studies have demonstrated that individuals living in polluted environments show altered antioxidant enzyme activities. Superoxide dismutase converts superoxide radicals into hydrogen peroxide, catalase decomposes hydrogen peroxide into water and oxygen, while glutathione peroxidase reduces lipid peroxides. When these enzymes become depleted, cells experience oxidative injury, leading to inflammation and degenerative diseases.

Lagos, being Nigeria’s most industrialized and densely populated city, presents a suitable setting for studying this biochemical impact. The investigation of antioxidant enzyme responses among exposed populations will deepen our understanding of how environmental factors influence health at the molecular level.

1.2 Statement of the Problem

Air pollution in Lagos has reached alarming levels due to unchecked industrial emissions and vehicular density. People living close to highways and factories are constantly exposed to toxic compounds that induce oxidative stress. However, limited biochemical data exist on how this exposure affects antioxidant enzyme systems in these populations. Without such data, it becomes difficult to design effective health policies or intervention programs. Thus, this study aims to evaluate antioxidant enzyme activities as biomarkers of oxidative stress in residents exposed to air pollution within Lagos metropolis.

1.3 Objectives of the Study

The major objective of this study is to evaluate the activities of selected antioxidant enzymes in individuals exposed to varying degrees of air pollution in Lagos metropolis.
The specific objectives include:

1. To determine the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in the blood of exposed and non-exposed individuals.

2. To compare the enzyme activities between residents of high-traffic and low-traffic areas.

3. To assess the relationship between the duration of exposure and enzyme activity levels.

4. To recommend appropriate preventive and health management strategies based on findings.

1.4 Research Questions

1. What are the levels of antioxidant enzyme activities in individuals exposed to air pollution in Lagos?

2. Is there a significant difference between enzyme activities in high-traffic and low-traffic areas?

3. How does the duration of exposure affect the activity of these enzymes?

4. What preventive measures can help reduce oxidative stress among exposed populations?

1.5 Significance of the Study

This study provides valuable biochemical evidence linking air pollution exposure to oxidative stress in humans. The findings will benefit health policymakers, environmental agencies, and medical researchers by highlighting the need for improved air quality management. Additionally, it will guide clinicians in using antioxidant biomarkers for early diagnosis of pollution-related diseases. For residents, the results will raise awareness of the health risks associated with prolonged exposure to polluted environments.

1.6 Scope of the Study

The research focuses on adult populations living in selected high-pollution and low-pollution areas of Lagos metropolis. It specifically measures three antioxidant enzymes—SOD, CAT, and GPx—from blood samples. Other non-enzymatic antioxidants and trace elements are not covered in this study.

1.7 Limitations of the Study

Some limitations include financial constraints, limited laboratory facilities for advanced enzyme analysis, and difficulty in obtaining consistent participation from volunteers. Nevertheless, all procedures were standardized to ensure accuracy and reliability of results.

1.8 Definition of Key Terms

• Air Pollution: The presence of harmful substances in the air, including particulate matter, gases, and chemical vapors.

• Oxidative Stress: A condition caused by an imbalance between the production of reactive oxygen species and the body’s antioxidant defenses.

• Antioxidant Enzymes: Biological molecules such as SOD, CAT, and GPx that protect cells from oxidative damage.

• Reactive Oxygen Species (ROS): Chemically reactive molecules derived from oxygen that can damage cellular components.

• Enzyme Activity: A measure of the catalytic ability of an enzyme under specific biochemical conditions.