Evaluation of Oxidative Stress Markers in Motorcycle Riders Regularly Exposed to Traffic Pollution in Anambra State

Evaluation of Oxidative Stress Markers in Motorcycle Riders Regularly Exposed to Traffic Pollution in Anambra State

Abstract

Exposure to traffic-related air pollutants is a growing public health concern, especially among motorcycle riders who spend long hours on congested roads. These pollutants, including carbon monoxide, nitrogen oxides, and particulate matter, generate reactive oxygen species (ROS) that can cause oxidative stress and cellular damage. This study evaluates oxidative stress biomarkers—such as malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH)—in motorcycle riders regularly exposed to traffic pollution in Anambra State.

Blood samples were collected from 60 commercial motorcycle riders and 30 non-exposed control subjects. Standard biochemical methods were used to assess oxidative stress parameters. The results revealed significantly higher MDA levels and lower SOD, CAT, and GSH activities among the exposed riders compared to the control group, indicating increased oxidative stress.

The findings suggest that chronic exposure to traffic pollutants elevates oxidative stress, which may predispose riders to cardiovascular and respiratory complications. Continuous environmental monitoring, use of protective gear, and antioxidant supplementation are recommended to reduce health risks among frequent road users.

CHAPTER ONE

1.0 Introduction

Air pollution remains one of the major environmental health challenges in developing countries. In urban areas of Nigeria, heavy traffic emissions release large amounts of harmful substances such as carbon monoxide, hydrocarbons, and fine particulate matter. These pollutants enter the bloodstream through inhalation and can trigger oxidative damage within body tissues.

Motorcycle riders represent one of the most vulnerable occupational groups exposed to traffic pollution. They spend several hours daily in congested conditions without protective barriers, inhaling toxic exhaust fumes and suspended particles. Prolonged exposure to these substances can lead to oxidative stress, a physiological imbalance between reactive oxygen species (ROS) and the body’s antioxidant defense mechanisms.

Oxidative stress plays a central role in the development of chronic diseases, including cardiovascular disorders, respiratory inflammation, and premature aging. Evaluating oxidative stress markers such as malondialdehyde (MDA), a lipid peroxidation product, and antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) provides insight into the biological effects of air pollution on human health.

In Anambra State, rapid urbanization and heavy motor traffic have worsened air quality. Motorcycle transport, being one of the most common means of movement, exposes thousands of riders to continuous pollutant inhalation. Assessing biochemical indicators of oxidative stress among these riders is, therefore, vital for early detection of potential health risks and for developing effective occupational health strategies.

1.1 Background of the Study

Traffic pollution is a major source of free radical generation in the human body. Pollutants like carbon monoxide, ozone, nitrogen oxides, and lead catalyze the formation of reactive oxygen species. When these molecules accumulate beyond the body’s antioxidant capacity, they initiate lipid peroxidation, protein oxidation, and DNA damage.

The human body naturally produces antioxidant enzymes to counter these effects. Superoxide dismutase (SOD) converts superoxide radicals into hydrogen peroxide, which catalase (CAT) further breaks down into water and oxygen. Glutathione (GSH), a non-enzymatic antioxidant, plays a key role in detoxifying reactive intermediates. However, excessive pollutant exposure depletes these antioxidants, resulting in oxidative imbalance.

Previous studies have linked oxidative stress to occupational exposure in factory workers, traffic wardens, and petrol station attendants. However, limited research has focused on commercial motorcycle riders in Nigeria, despite their high exposure levels. This study, therefore, examines oxidative stress markers among motorcycle riders in Anambra State to evaluate the impact of traffic pollution on their biochemical health.

1.2 Statement of the Problem

Motorcycle riders in Anambra State are continuously exposed to vehicle exhaust fumes, dust, and industrial pollutants while working long hours on busy roads. Despite this exposure, there is little biochemical data assessing how such pollution affects their oxidative stress levels.

Oxidative stress has been associated with inflammation, cellular aging, and degenerative diseases. Without proper evaluation and preventive measures, the health of these riders may deteriorate over time. Thus, it is crucial to biochemically assess oxidative stress biomarkers to provide evidence-based information that can guide occupational health policies and interventions in the state.

1.3 Aim and Objectives of the Study

Aim:
To evaluate oxidative stress markers in motorcycle riders regularly exposed to traffic pollution in Anambra State.

Objectives:

1. To determine serum levels of malondialdehyde (MDA) as an indicator of lipid peroxidation.

2. To measure the activities of antioxidant enzymes—superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH)—in the study population.

3. To compare oxidative stress markers between exposed motorcycle riders and unexposed control subjects.

4. To assess the relationship between exposure duration and oxidative stress intensity.

1.4 Significance of the Study

This study provides vital insight into how traffic pollution impacts oxidative balance in occupationally exposed individuals. Its findings will help public health authorities, environmental regulators, and occupational safety agencies develop strategies to reduce exposure-related health risks.

Furthermore, the research highlights the potential benefits of antioxidant-rich diets and the use of protective masks among riders. Policymakers can also use the data to advocate for emission control, improved traffic management, and regular health screening of commercial riders.

1.5 Scope of the Study

The study focuses on commercial motorcycle riders operating in major cities of Anambra State, such as Awka, Onitsha, and Nnewi. It evaluates specific oxidative stress biomarkers—MDA, SOD, CAT, and GSH—in blood samples collected from participants. Environmental pollutant quantification and other unrelated biochemical parameters are not included within this research scope.

1.6 Definition of Key Terms

• Oxidative Stress: An imbalance between the production of free radicals and the body’s ability to neutralize them.

• Reactive Oxygen Species (ROS): Chemically reactive molecules containing oxygen, such as superoxide and hydroxyl radicals.

• Antioxidant Enzymes: Biological molecules that protect cells from oxidative damage (e.g., SOD, CAT, GSH).

• Malondialdehyde (MDA): A by-product of lipid peroxidation used as a marker of oxidative stress.

• Traffic Pollution: Air contamination caused by emissions from vehicles, including carbon monoxide and particulates.