Access to safe drinking water remains a critical challenge across urban and semi-urban areas in Nigeria. In Uyo, Akwa Ibom State, residents rely heavily on groundwater sources, particularly hand dug wells and boreholes, for their daily water supply. Understanding the quality of water from these sources is essential for public health and informed decision-making. This article presents a comparative analysis of water quality from hand dug wells and boreholes in Uyo metropolis, drawing on research by Dr. Ukpong and Abaraogu that examined physical, chemical, and bacteriological parameters against WHO drinking water standards. For a broader understanding of groundwater systems, readers may refer to Hydrology and Water Resources Engineering Watershed Analysis Open Channel Flow Groundwater Hydrology and Water Quality, which covers fundamental principles of water resource assessment.
Study Background and Methodology
The Water Supply Challenge in Uyo Metropolis
According to WHO, approximately 1.1 billion people globally lack access to improved drinking water supplies. In Uyo, high population density, poor sanitation practices, and weak enforcement of environmental regulations have contributed significantly to the pollution of water sources. Groundwater contaminants typically originate from three main categories:
- Municipal sources: leakages from liquid waste systems and solid waste from landfills
- Industrial sources: liquid waste tanks, pipeline leakages, oil field operations, and brines
- Agricultural sources: irrigation return flows carrying saline and chemical residues
These problems have driven a rapid increase in hand dug wells and boreholes, some located dangerously close to soak-away pits and pit latrines, increasing contamination risk.
Research Objectives and Scope
The primary objective was to carry out comprehensive water quality analysis on samples from randomly selected hand dug wells and boreholes in Uyo metropolis to:
- Determine the level of physical, chemical, and bacteriological parameters in each sample
- Assess the suitability of these water sources against WHO drinking water quality standards
The study covered three hand dug wells at Itak Mbak, Anua, and Nung Udoe, and three boreholes at Udoh Street, Oron Road, and Ibiaku, providing a representative cross-section of groundwater sources across the metropolis.
Sampling and Analytical Methods
Samples were collected using sterilized hard plastic screw-capped bottles. Bacteriological samples were autoclaved for 15 minutes at 121 degrees Celsius before transport. All analyses were conducted at the Department of Soil Science Laboratory, University of Uyo, following WHO standard methods. Physical parameters measured included turbidity and temperature. Chemical parameters covered pH, electrical conductivity, total dissolved solids, hardness, dissolved oxygen, biochemical oxygen demand, sulphate, nitrate, and heavy metals (iron, zinc, lead, calcium, magnesium). Bacteriological analysis focused on total coliform count as an indicator of faecal contamination.
Physical and Chemical Parameters: Results and Discussion
Hardness Levels Across Sources
Water hardness reflects the concentration of calcium and magnesium ions. Borehole samples showed values of 66.11 mg/l at Udoh Street, 71.03 mg/l at Oron Road, and 58.92 mg/l at Ibiaku, placing them in the soft water category (0 to 75 mg/l). Well samples from Itak Mbak (83.2 mg/l) and Nung Udoe (81.46 mg/l) fell into the moderately hard water category (75 to 120 mg/l), while Anua well (61.99 mg/l) remained soft. On average, borehole water was softer than hand dug well water. All samples met the WHO acceptable limit of 150 mg/l, and moderately hard well water can be treated with simple boiling.
pH and Corrosion Potential
Most samples fell within the WHO recommended pH range of 6.5 to 8.5. However, the Udoh Street borehole (B1) recorded a pH of 6.3, indicating mild acidity. Acidic water has increased capacity to attack geological materials and leach toxic trace metals, making it potentially harmful for human consumption. This can be corrected with lime treatment. Well samples showed pH values from 8.1 to 8.22, indicating slightly alkaline conditions within acceptable limits.
Dissolved Oxygen and Biochemical Oxygen Demand
The mean dissolved oxygen (DO) values for boreholes (4.161 mg/l) were lower than those for wells and fell below the WHO standard of 5 to 14 mg/l. Udoh Street (4.039 mg/l), Oron Road (4.31 mg/l), Ibiaku (4.133 mg/l), and Nung Udoe well (4.93 mg/l) all failed to meet WHO requirements. Only Itak Mbak well (5.81 mg/l) and Anua well (5.1 mg/l) were within acceptable limits.
Biochemical oxygen demand (BOD) results were uniformly concerning. All samples recorded BOD values far exceeding the WHO standard of 2 to 4 mg/l. Borehole values ranged from 14.99 to 16.21 mg/l, while well values ranged from 19.09 to 20.41 mg/l. High BOD indicates organic pollution and reduced oxygen availability to support water quality.
Sulphate, Nitrate, and Heavy Metals
Sulphate concentrations ranged from 3.79 to 4.98 mg/l, well within the WHO limit of 50 mg/l. Nitrate levels ranged from 0.099 to 2.418 mg/l, all below the WHO maximum of 50 mg/l. Heavy metal analysis showed that iron, zinc, calcium, and magnesium concentrations in all sources were within WHO acceptable limits. However, lead levels presented a notable concern. Borehole samples from all three locations recorded lead levels of 0.04 mg/l, while Anua well recorded 0.03 mg/l, all exceeding the WHO limit of 0.01 mg/l. Only Itak Mbak well and Nung Udoe well met the standard at 0.01 mg/l. While not an immediate health risk, these levels warrant monitoring.
Bacteriological Quality and Comparative Summary
Total Coliform Count
The WHO standard for total coliform count in drinking water is zero. All samples recorded values slightly above this limit. Borehole samples showed counts of 0.01 to 0.03 mg/l, while well samples had a mean of 0.03 mg/l across all locations. The presence of coliforms indicates faecal contamination and represents a potential health risk. This finding is particularly relevant given the proximity of many water sources to waste disposal sites. For readers interested in how water quality affects household use, Hard Water and Gray Water Understanding Water Quality and Reuse offers practical guidance on managing water quality at the domestic level.
Comparative Summary Table
| Parameter | Borehole Range | Well Range | WHO Limit | Compliance Status |
|---|---|---|---|---|
| Hardness (mg/l) | 58.92 – 71.03 | 61.99 – 83.20 | 150 | All compliant |
| pH | 6.30 – 7.34 | 8.10 – 8.22 | 6.5 – 8.5 | B1 below limit; others compliant |
| Electrical Conductivity (us/cm) | 0.006 – 0.27 | 0.01 – 1.66 | 1000 | All compliant |
| Turbidity (NTU) | 2.00 – 3.44 | 3.66 – 4.99 | 10 | All compliant |
| TDS (mg/l) | 0.01 – 0.31 | 0.08 – 0.17 | 500 | All compliant |
| Dissolved Oxygen (mg/l) | 4.039 – 4.31 | 4.93 – 5.81 | 5 – 14 | Most boreholes and W3 below limit |
| BOD (mg/l) | 14.99 – 16.21 | 19.09 – 20.41 | 2 – 4 | All exceeded limit |
| Sulphate (mg/l) | 3.79 – 4.98 | 3.93 – 4.66 | 50 | All compliant |
| Nitrate (mg/l) | 0.099 – 1.031 | 2.10 – 2.418 | 50 | All compliant |
| Total Coliform (mg/l) | 0.01 – 0.03 | 0.03 | 0 | All slightly above limit |
| Lead (mg/l) | 0.04 | 0.01 – 0.03 | 0.01 | Most boreholes and W2 above limit |
The analysis shows that while both sources are generally suitable for drinking, each has specific weaknesses. Borehole water is softer with lower turbidity but underperforms on DO and lead content. Well water shows better DO levels but has higher hardness and BOD. Understanding Mild Steel Versus High Yield Steel Reinforcement in Water Retaining Structures is also relevant when considering materials for water infrastructure that must resist corrosion and maintain integrity over time.
Conclusions and Recommendations for Water Quality Management
Summary of Key Findings
Based on the comprehensive analysis, the following conclusions are drawn regarding groundwater quality in Uyo metropolis:
- Water from hand dug wells is harder than borehole water, but this can be reduced through boiling
- Dissolved oxygen in boreholes did not meet WHO standards, while well water performed better
- BOD for both sources was far above the WHO limit, indicating organic pollution
- Sulphate and nitrate concentrations met WHO standards comfortably
- Total coliform counts were slightly above WHO limits, with wells showing higher counts
- All heavy metals except lead fell within WHO limits; lead was slightly elevated in boreholes
Recommendations for Stakeholders
For Government Agencies
- Standard water treatment measures should address pH adjustment, coliform disinfection, and lead removal at affected sites
- Regular water quality monitoring programs should be established with quarterly analysis
- Hygienically approved waste disposal methods must be adopted to prevent hazardous material dumping
- Stricter enforcement of environmental sanitation laws should prevent well construction near contamination sources
For Residents and Water Users
- Water from both sources should be treated before drinking through boiling, filtration, or chlorination
- Changes in water taste, color, or odor should be reported to health authorities
- Well owners should ensure proper well-head protection with sanitary seals and concrete aprons
- Regular testing of private wells is recommended, especially after heavy rainfall
For site engineers involved in water infrastructure projects, Detailed Analysis of Construction Quality Tools for a Site Engineer provides practical guidance on maintaining quality standards during water supply system installation and maintenance.
The Way Forward
This study provides critical baseline data on groundwater quality in Uyo metropolis. The findings reveal that while both hand dug wells and boreholes serve as important drinking water sources, each has specific deficiencies requiring attention. Borehole water, despite its deeper aquifer source, showed issues with pH, DO, and lead. Hand dug well water, while more vulnerable to surface contamination, demonstrated better DO levels.
The key to safe drinking water in Uyo lies in implementing appropriate treatment measures for each source. Simple interventions such as pH adjustment with lime, boiling for hardness reduction and disinfection, and regular heavy metal monitoring can dramatically improve water quality. Public awareness and regulatory enforcement are equally important to address root causes of contamination, particularly improper waste disposal threatening both shallow and deep groundwater aquifers. Only through scientific monitoring, regulatory action, and community engagement can residents be assured of safe, sustainable drinking water.