Biochemical Analysis of Drinking Water from Ilorin – Fluoride, Nitrates, Heavy Metals – and Associated Health Biomarkers

Biochemical Analysis of Drinking Water from Ilorin – Fluoride, Nitrates, Heavy Metals – and Associated Health Biomarkers

ABSTRACT

Access to safe drinking water remains a fundamental requirement for good health, yet water contamination continues to threaten public health in many Nigerian cities. This study investigates the biochemical composition of drinking water sources in Ilorin, Kwara State, focusing on fluoride, nitrate, and heavy metal levels, and evaluates their possible effects on human health biomarkers.

Water samples were collected from boreholes, wells, and sachet water across selected urban and rural areas. Laboratory analyses determined the concentrations of fluoride, nitrates, and heavy metals (lead, cadmium, and iron) using spectrophotometric and atomic absorption techniques. Blood samples from residents consuming these water sources were analyzed for biochemical health markers such as serum creatinine, liver enzymes (ALT, AST), and hemoglobin levels.

Results revealed variations in contaminant concentrations between urban and rural sources. Some samples exceeded World Health Organization (WHO) limits, especially for fluoride and lead. Elevated levels of these elements were associated with mild alterations in kidney and liver function markers. The findings suggest that consistent monitoring of drinking water quality and community education are essential to prevent long-term health effects.

Keywords: Drinking water, Fluoride, Nitrate, Heavy metals, Biochemical biomarkers, Ilorin

CHAPTER ONE

1.0 Introduction

Water plays a vital role in sustaining human life and maintaining physiological balance. Safe drinking water is essential for health, yet contamination by industrial waste, agricultural runoff, and poor sanitation remains a major concern in developing nations. In Nigeria, especially in cities such as Ilorin, rapid urbanization has led to increased groundwater exploitation without adequate quality control. The presence of contaminants such as fluoride, nitrates, and heavy metals can significantly affect human biochemical and physiological systems.

High fluoride concentrations in water may cause dental or skeletal fluorosis, while nitrates can induce methemoglobinemia, particularly in children. Heavy metals such as lead and cadmium are toxic even at low concentrations and may impair kidney and liver function. Monitoring these contaminants and their biochemical effects provides valuable insight into community health risks.

1.1 Statement of the Problem

The increasing dependence on groundwater and sachet water in Ilorin has raised concerns about their safety. Industrial discharge, poor waste management, and agricultural practices contribute to rising contaminant levels. Many residents consume this water daily without knowing the potential biochemical implications. Despite isolated studies, there is limited comprehensive data linking specific water contaminants to health biomarkers among Ilorin residents. This research addresses that gap.

1.2 Aim and Objectives of the Study

Aim:
To assess the biochemical quality of drinking water from Ilorin and evaluate associated health biomarkers among consumers.

Objectives:

1. Measure fluoride, nitrate, and heavy metal concentrations in selected drinking water sources in Ilorin.

2. Compare observed contaminant levels with WHO permissible limits.

3. Determine selected biochemical health markers (creatinine, liver enzymes, hemoglobin) among residents.

4. Assess the relationship between contaminant exposure and biochemical indicators of health.

1.3 Research Questions

1. What are the concentrations of fluoride, nitrate, and heavy metals in Ilorin’s drinking water sources?

2. How do these values compare with WHO standards for safe water?

3. Do variations in water quality correlate with changes in biochemical health biomarkers?

4. What preventive strategies can improve water safety and reduce exposure risks?

1.4 Research Hypotheses

• H₀₁: There is no significant difference in contaminant concentrations between various water sources in Ilorin.

• H₁₁: There is a significant difference in contaminant concentrations between different water sources.

• H₀₂: Biochemical health markers of residents are not affected by exposure to contaminated water.

• H₁₂: Exposure to contaminated water significantly affects biochemical health markers.

1.5 Significance of the Study

This study provides evidence-based insight into the biochemical safety of drinking water in Ilorin. By linking water quality to human health markers, the research supports environmental health policies and public awareness campaigns. It contributes to academic knowledge in biochemical toxicology and environmental biochemistry while guiding health agencies on appropriate mitigation strategies.

1.6 Scope of the Study

The research covers selected boreholes, wells, and sachet water samples from both urban and rural parts of Ilorin, Kwara State. Laboratory analyses focus on fluoride, nitrate, and heavy metals. The biochemical assessment includes blood markers such as creatinine, liver enzymes, and hemoglobin among adult residents. Other contaminants like microbial pathogens are excluded.

1.7 Definition of Terms

• Fluoride: A naturally occurring element that, in high concentrations, can cause dental or skeletal fluorosis.

• Nitrate: A chemical compound from fertilizers and waste, capable of disrupting oxygen transport in blood.

• Heavy Metals: Metallic elements like lead and cadmium that are toxic to living organisms even at low levels.

• Biochemical Biomarkers: Measurable indicators such as enzymes or metabolites used to assess organ function.

• Water Contamination: The presence of harmful substances in water that make it unsafe for consumption.

CHAPTER TWO

2.0 Literature Review

2.1 Overview of Water Quality and Public Health

Water quality plays a fundamental role in maintaining health. Contaminated water is responsible for a significant portion of disease burdens worldwide. According to WHO (2022), about 25% of global health problems in developing countries are linked to unsafe water and inadequate sanitation. Chemical contaminants, especially fluoride, nitrates, and heavy metals, have both acute and chronic biochemical consequences.

2.2 Fluoride Contamination and Health Implications

Fluoride naturally occurs in rocks and soils, entering groundwater through leaching. At low levels, it supports dental health; however, excessive intake leads to fluorosis, which affects bones and teeth. Long-term exposure has also been associated with altered calcium metabolism and liver enzyme activity (Nwosu & Agwu, 2021). The degree of toxicity depends on concentration, duration, and individual susceptibility.

2.3 Nitrates and Biochemical Effects

Nitrates mainly enter groundwater from agricultural fertilizers and decaying organic matter. When ingested, they convert to nitrites, which can oxidize hemoglobin into methemoglobin, reducing oxygen transport capacity. In children, this causes “blue baby syndrome.” Prolonged nitrate exposure can also lead to oxidative stress, mitochondrial dysfunction, and impaired enzymatic activities (Chukwu et al., 2019).

2.4 Heavy Metals in Water and Human Health

Heavy metals such as lead, cadmium, and mercury pose serious biochemical risks. Lead accumulates in the body, damaging the nervous system, liver, and kidneys. Cadmium affects renal function and alters antioxidant enzyme activities. Continuous exposure may disrupt protein synthesis and increase oxidative stress (Okafor et al., 2020). These elements interfere with enzymatic cofactors and generate free radicals that cause lipid peroxidation.

2.5 Biochemical Markers of Organ Function

Blood biomarkers provide early detection of toxic effects caused by contaminants.

• Creatinine is a key marker of kidney function. Elevated levels indicate renal stress due to heavy metal exposure.

• Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) reflect liver integrity. Increased enzyme activity suggests hepatic damage.

• Hemoglobin levels can reveal anemia resulting from nitrate toxicity or lead interference with iron metabolism (WHO, 2021).

2.6 Environmental and Socioeconomic Context of Ilorin

Ilorin, located in Kwara State, has witnessed rapid urban expansion over the past two decades. Industrialization, agricultural runoff, and poor waste disposal systems have contributed to groundwater contamination. Many communities rely on boreholes and wells, often without regular water testing. Consequently, both urban and rural residents may face biochemical risks from chronic low-level contaminant exposure.

2.7 Mechanisms of Toxicity and Oxidative Stress

Exposure to fluoride, nitrates, and heavy metals triggers oxidative stress by generating reactive oxygen species (ROS). These reactive molecules damage lipids, proteins, and DNA, altering enzyme function. The body’s antioxidant defenses—superoxide dismutase, catalase, and glutathione peroxidase—attempt to neutralize ROS. However, prolonged exposure may overwhelm these systems, resulting in metabolic imbalance and organ dysfunction.

2.8 Regulatory Standards and Health Policies

The World Health Organization recommends maximum permissible limits for fluoride (1.5 mg/L), nitrate (50 mg/L), and lead (0.01 mg/L). Nigeria’s Standard Organization (SON) adopts similar thresholds. Despite this, enforcement remains weak, and routine biochemical surveillance is uncommon. Strengthening environmental regulations and health-based water monitoring programs can protect vulnerable populations.

2.9 Gaps in Literature

Few studies in Ilorin have integrated chemical water analysis with biochemical health assessments. Most existing research either focused on physical parameters or microbiological contaminants. This study bridges the gap by simultaneously evaluating water chemistry and human health biomarkers, providing a clearer picture of contamination effects.

2.10 Summary

Water quality assessment must extend beyond chemical measurements to include biological and biochemical outcomes. Fluoride, nitrates, and heavy metals in drinking water can silently impair organ function through oxidative and metabolic disturbances. This research, therefore, offers essential biochemical insights into the health risks of contaminated water in Ilorin.