Comparative Biochemical Analysis of Heavy Metal Levels in Sachet Water Sold in Lagos and Oyo States

ABSTRACT

Sachet water is one of the most common sources of drinking water in Nigeria, especially in rapidly growing urban areas. Its popularity continues to rise because it is affordable and easy to access. However, concerns about heavy metal contamination remain significant, particularly in regions with high industrial activity. This study compares the concentrations of lead (Pb), cadmium (Cd), chromium (Cr), and zinc (Zn) in sachet water sold in Lagos and Oyo States while assessing the biochemical health risks associated with long-term consumption.

Researchers collected 120 sachet water samples from markets, roadside vendors, and production outlets in both states. They analyzed the heavy metal levels using atomic absorption spectrophotometry and compared the findings with WHO and SON drinking water standards. The results showed that several Lagos brands contained higher levels of Pb and Cd, likely due to industrial pollution and environmental exposure. Although many samples stayed within permissible limits, a few brands exceeded recommended thresholds, which raises public health concerns.

Overall, this study emphasizes the importance of improved regulatory monitoring and consistent quality control. It also encourages producers to adopt safer production practices and urges consumers to remain aware of potential risks. Strengthening routine inspection will ultimately help ensure safer drinking water across both states.

Keywords: sachet water, heavy metals, public health, biochemical contamination, Lagos, Oyo

CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

Safe drinking water plays an essential role in maintaining good health. Yet many Nigerians depend on sachet water daily because treated tap water remains limited in several communities. Although sachet water is convenient, its safety depends on the quality of the source water, hygiene during production, and proper handling.

Heavy metal contamination has become increasingly problematic due to industrialization, poor waste disposal, and environmental degradation. Metals such as lead, cadmium, chromium, and zinc can enter water sources through runoff, leaking pipes, or contaminated soil. When people consume contaminated water over a long period, these metals may accumulate in the body and trigger biochemical imbalance. Consequently, they may contribute to liver damage, kidney dysfunction, neurological disorders, and oxidative stress.

Lagos and Oyo States remain major commercial centers with high sachet water consumption. Lagos, in particular, experiences intense industrial activities that may increase contamination risks. Oyo, though less industrialized, is rapidly urbanizing, which may also affect water quality. Therefore, a comparative biochemical assessment of sachet water from both states will provide insights into contamination patterns and potential health threats.

1.2 Statement of the Problem

Many consumers assume that sachet water is always safe because it is factory-sealed. However, several Nigerian studies have reported heavy metal contamination in different brands. Poor regulation, inconsistent manufacturing practices, and environmental pollution contribute to these risks.

Furthermore, people rarely have access to information about the biochemical safety of the water they drink. Without regular monitoring, communities may unknowingly consume water that contains heavy metals capable of damaging vital organs. Therefore, a comprehensive comparison between Lagos and Oyo States is necessary to understand contamination trends and protect public health.

1.3 Aim of the Study

The study aims to compare the levels of selected heavy metals in sachet water sold in Lagos and Oyo States and evaluate the potential biochemical health risks associated with consumption.

1.4 Objectives of the Study

1. To measure the concentrations of Pb, Cd, Cr, and Zn in sachet water from Lagos and Oyo States.

2. To compare heavy metal levels between the two states.

3. To assess the level of compliance with WHO and SON drinking water standards.

4. To evaluate possible biochemical health risks linked to long-term consumption.

5. To recommend strategies for improving water safety and regulatory monitoring.

1.5 Research Questions

1. What are the heavy metal concentrations in sachet water sold in Lagos and Oyo States?

2. Are there significant differences in contamination levels between both states?

3. Do the metal concentrations meet WHO and SON safety standards?

4. What biochemical risks may arise from long-term consumption of contaminated sachet water?

1.6 Research Hypotheses

H₀₁: There is no significant difference in heavy metal concentrations in sachet water from Lagos and Oyo States.
H₁₁: There is a significant difference in heavy metal concentrations in sachet water from Lagos and Oyo States.

H₀₂: Heavy metal levels in sachet water do not exceed WHO/SON permissible limits.
H₁₂: Heavy metal levels in sachet water exceed WHO/SON permissible limits.

1.7 Significance of the Study

This study benefits several groups:

• Public health officials: It provides evidence on possible biochemical risks associated with drinking sachet water.

• Regulatory agencies: It supports stronger monitoring and enforcement of water quality standards.

• Producers: It highlights the need for improved production processes and hygiene practices.

• Researchers: It serves as a baseline for future studies on water safety and contamination trends.

• Consumers: It creates awareness about potential health hazards and encourages informed choices.

1.8 Scope of the Study

The study focuses on sachet water sold in Lagos and Oyo States. It analyzes four heavy metals—Pb, Cd, Cr, and Zn—using laboratory-based biochemical assessment. Other contaminants, such as microbial organisms or organic pollutants, fall outside the study scope.

1.9 Limitations of the Study

• The sample does not include every sachet water brand sold in both states.

• Seasonal changes may affect contamination levels, but the study is limited to one sampling period.

• Only selected heavy metals were analyzed due to time and resource constraints.

1.10 Definition of Key Terms

• Heavy Metals: Toxic metallic elements that can accumulate in tissues and disrupt normal biological functions.

• Sachet Water: Single-use packaged drinking water sealed in plastic containers.

• Biochemical Contamination: Introduction of harmful substances that impair metabolic processes in living organisms.

• AAS (Atomic Absorption Spectrophotometry): A laboratory method used to detect and quantify metal concentrations.