Project – Bacteriological Assessment of Drinking Water and Its Public Health Implications. A Study of Selected boreholes and household water sources in Owerri Municipal, Imo State

CHAPTER ONE

INTRODUCTION

1.1 Background to the Study

Drinking water is essential for human survival, personal hygiene, food preparation, sanitation, and the maintenance of general health. However, the availability of water does not necessarily guarantee its safety for human consumption, as water may contain pathogenic microorganisms capable of causing disease. The bacteriological quality of drinking water is therefore an important indicator of public health and environmental sanitation. Contaminated water can transmit microorganisms responsible for gastrointestinal infections and other waterborne illnesses, particularly among children, older adults, and individuals with weakened immune systems. The World Health Organization (WHO, 2022) explains that drinking-water safety depends on effective risk assessment, routine monitoring, sanitary inspection, and appropriate preventive measures throughout the water supply system. Similarly, Bain et al. (2014), in a systematic review of faecal contamination in drinking-water supplies, demonstrated that microbiological contamination remains a concern across different water supply types and geographical settings. Consequently, the bacteriological assessment of drinking water is necessary to determine whether water sources are suitable for consumption and to identify potential risks to the health of communities.

Bacteriological contamination occurs when bacteria enter water through sources such as human or animal faeces, sewage, refuse, contaminated soil, drainage channels, and unhygienic handling practices. Such contamination may occur at the source, during transportation, within storage facilities, or at the point of consumption. Some bacteria are environmental organisms that may indicate general microbial contamination, whereas others are associated with faecal pollution and the possible presence of enteric pathogens. The detection of indicator organisms, particularly Escherichia coli, is widely used to assess the microbiological safety of drinking water because it provides evidence of faecal contamination. The WHO (2022) recommends that E. coli should not be detectable in any 100-millilitre sample of drinking water. Bain et al. (2014) also reported that faecal indicator organisms are useful for assessing drinking-water safety, although the interpretation of results must consider the water source, sampling method, and local environmental conditions. Therefore, bacteriological analysis provides important evidence for determining whether water is contaminated and whether corrective measures are required to protect consumers.

Boreholes are important sources of water for households, businesses, institutions, and communities, particularly where public water supply is inadequate or unreliable. Groundwater is often perceived as safer than surface water because soil and geological formations may naturally filter some contaminants before the water reaches an aquifer. Nevertheless, borehole water is not automatically safe for drinking, as microorganisms can enter groundwater through poorly constructed boreholes, damaged protective structures, inadequate sealing, contaminated recharge areas, or the infiltration of wastewater and faecal material. The risk may be increased when boreholes are situated close to septic tanks, soakaway pits, open drains, refuse dumps, or other potential sources of pollution. Ewelike et al. (2022), in their bacteriological assessment of borehole water in communities in Owerri West, Imo State, reported substantial bacterial and coliform counts and recovered organisms including Escherichia coli, Shigella species, and Klebsiella species. Their findings demonstrate the importance of investigating borehole water rather than assuming that groundwater is microbiologically safe. A bacteriological assessment of selected boreholes in Owerri Municipal is therefore relevant for establishing the quality of water used by residents.

Household water sources include water obtained from boreholes, public taps, packaged water, wells, rainwater collection systems, and other sources used for drinking and domestic purposes. Even when water is relatively safe at the point of collection, its quality may deteriorate during transportation, handling, and storage. Contamination can occur when water is stored in uncovered containers, when hands or unclean utensils come into contact with the water, or when storage vessels are not regularly cleaned. Repeated withdrawal from containers and the use of contaminated scoops may introduce microorganisms into previously safer water. Wright et al. (2004), in a review of microbial contamination of drinking water during household storage, identified water collection and domestic storage as important stages at which microbiological quality may deteriorate. Similarly, the WHO (2022) emphasises that drinking-water safety should be maintained from the source to the point of consumption. Assessing selected household water sources alongside boreholes is therefore important because it can help distinguish contamination associated with the original supply from contamination that may occur during domestic handling and storage.

Several bacterial organisms are of public health importance in drinking-water assessment because their presence may indicate contamination or a potential risk of infection. These organisms include Escherichia coli, Salmonella species, Shigella species, and other bacteria associated with enteric diseases. E. coli is particularly useful as an indicator of faecal pollution, while the detection of particular pathogenic strains or other enteric pathogens may provide more direct evidence of a potential health hazard. Exposure to water contaminated with pathogenic bacteria can contribute to diarrhoeal diseases, dysentery, enteric fever, and other infections, depending on the organisms present and the susceptibility of the exposed population. The WHO (2022) identifies microbiological hazards as a central consideration in drinking-water safety and recommends appropriate verification and risk-management measures. Bain et al. (2014) further demonstrated the relevance of faecal contamination in drinking-water sources to public health protection. It is therefore important that bacteriological investigations identify relevant bacterial groups and, where possible, distinguish general bacterial growth from evidence of faecal contamination or specific pathogens.

The bacteriological quality of water is especially important in urban communities where population growth, increased demand for water, inadequate waste management, and differences in household sanitation may influence contamination risks. Owerri Municipal, in Imo State, is an urban area where residents obtain water from different sources, including boreholes and household supplies. Previous investigations in Owerri and neighbouring areas of Imo State have demonstrated that the quality of groundwater and stored water can vary considerably between locations. For instance, Peter-Ikechukwu et al. (2015) assessed borehole water in parts of Owerri and reported variations in coliform counts among sampled sources. Ewelike et al. (2022) also documented bacteriological contamination in borehole water from selected communities in Owerri West. Although these studies provide relevant evidence, their findings cannot automatically be generalised to every borehole or household water source in Owerri Municipal because contamination levels may differ according to local environmental conditions, borehole construction, sanitation infrastructure, and handling practices. A new assessment of selected water sources in Owerri Municipal is therefore necessary to establish their bacteriological condition during the specified study period and identify potential public health concerns.

The bacteriological assessment of drinking water provides scientific evidence for evaluating water safety, identifying possible contamination sources, and recommending appropriate preventive measures. Such an assessment commonly involves the collection of representative water samples, the determination of bacterial counts, the detection of indicator organisms, and the identification of selected bacterial isolates using recognised microbiological methods. The results can then be compared with relevant drinking-water quality standards, including the WHO guideline that E. coli should not be detectable in a 100-millilitre drinking-water sample. The WHO (2022) recommends risk-based water safety management and independent surveillance, while Ewelike et al. (2022) demonstrate the practical value of bacteriological investigation in identifying contamination in borehole water within Imo State. Despite the existence of earlier studies, water quality may change over time and vary between individual sources, making continued local assessment important. This study therefore seeks to assess the bacteriological quality of selected boreholes and household water sources in Owerri Municipal, Imo State, with particular attention to bacterial counts, indicator organisms, selected bacterial isolates, and the public health implications of the findings. The evidence generated may support public awareness, safer household water handling, improved sanitation practices, and the appropriate monitoring of drinking-water sources.

1.2 Statement of the Problem

The safety of drinking water remains an important public health concern because water contaminated with pathogenic microorganisms can expose consumers to preventable infections. Although boreholes and household water supplies are widely used to meet domestic water needs, their microbiological quality may be affected by inadequate sanitation, defective borehole construction, poor environmental management, and unhygienic water handling. The appearance, taste, and odour of water cannot reliably establish its bacteriological safety because harmful microorganisms may be present without producing noticeable changes in these characteristics. The WHO (2022) emphasises that drinking-water safety must be verified through appropriate monitoring and risk-management procedures. Consequently, relying solely on the perceived cleanliness of water sources may expose households to microbiological hazards that require laboratory investigation.

A further problem is the possibility of faecal contamination of groundwater and household water supplies. Poorly maintained boreholes, nearby septic systems, leaking sewage facilities, contaminated drainage, and unsafe waste disposal may create pathways through which microorganisms enter water sources. In addition, water that is initially of acceptable quality may become contaminated during collection, transportation, and storage. Bain et al. (2014) identified faecal contamination as a continuing concern in drinking-water supplies, while Wright et al. (2004) demonstrated that microbiological quality can deteriorate between collection and consumption. These findings highlight the importance of assessing both the original water source and the conditions under which water is handled and stored within households.

In Owerri Municipal, residents depend on different sources of water for drinking, cooking, and other domestic activities. Previous studies conducted in Owerri and neighbouring areas have reported variations in the bacteriological quality of borehole and other domestic water sources. Peter-Ikechukwu et al. (2015) reported differences in coliform counts among borehole samples from parts of Owerri, while Ewelike et al. (2022) identified substantial bacterial contamination in borehole water from selected communities in Owerri West. However, findings from these studies do not establish the current bacteriological quality of all selected boreholes and household water sources within Owerri Municipal. Differences in location, sampling periods, environmental conditions, water handling practices, and source characteristics make further local assessment necessary.

The central problem addressed by this study is the need for current, source-specific bacteriological evidence concerning selected boreholes and household water sources in Owerri Municipal, Imo State. Without such evidence, the extent of bacterial contamination, the occurrence of faecal indicator organisms, and the possible presence of selected bacterial pathogens in the sampled water sources cannot be established reliably. This information is important for assessing compliance with drinking-water microbiological standards and identifying potential public health concerns. The study will therefore examine selected water samples using appropriate laboratory procedures and interpret the results in relation to recognised water quality guidelines. The findings may provide evidence to support safer drinking-water practices, improved household water handling, and recommendations for routine monitoring, without presuming in advance that every sampled source is contaminated.

1.3 Aim and Objectives of the Study

1.3.1 Aim of the Study

The aim of this study is to assess the bacteriological quality of selected boreholes and household water sources in Owerri Municipal, Imo State, and examine the public health implications of the findings.

1.3.2 Specific Objectives

The specific objectives are to:

1. Determine the total heterotrophic bacterial counts and coliform counts of water samples collected from selected boreholes and household water sources in Owerri Municipal.

2. Isolate and identify selected bacterial organisms present in the sampled water sources using appropriate microbiological methods.

3. Compare the bacteriological quality of the selected boreholes and household water sources with relevant drinking-water microbiological standards.

4. Assess the potential public health implications of the bacteriological findings and examine their relationship with selected source characteristics and household water-handling practices, where these data are available.

1.4 Research Questions

The study will answer the following research questions:

1. What are the total heterotrophic bacterial counts and coliform counts of water samples collected from the selected boreholes and household water sources in Owerri Municipal?

2. Which bacterial organisms can be isolated and identified from the sampled water sources?

3. To what extent do the sampled water sources comply with recognised drinking-water microbiological standards?

4. What are the potential public health implications of the bacteriological findings, and how are these findings associated with selected source characteristics and household water-handling practices?

1.5 Research Hypothesis

The following null hypothesis will guide the study:

H₀: There is no statistically significant difference in the bacteriological quality of water samples collected from selected boreholes and household water sources in Owerri Municipal, Imo State.

The hypothesis will be tested at the 0.05 level of significance using an appropriate statistical method based on the sampling design, number of samples, and distribution of the bacterial count data. Where samples are collected in matched pairs or repeated measurements, the statistical analysis will account for the sampling structure.

1.6 Significance of the Study

The findings of this study are expected to be beneficial to households, public health authorities, environmental health officers, water suppliers, researchers, and the wider community.

Households and consumers: The study may provide information on the bacteriological quality of water used for drinking and domestic purposes in Owerri Municipal. The findings may help households understand the importance of hygienic water collection, safe storage, and appropriate treatment before consumption. Wright et al. (2004) demonstrated the importance of maintaining water quality between collection and consumption, making household water-handling practices an important consideration in public health protection.

Public health authorities: The findings may provide local evidence to support drinking-water surveillance and the identification of water sources requiring further investigation or corrective action. The WHO (2022) recommends routine monitoring and risk-based management to reduce exposure to microbiological hazards in drinking water.

Environmental health officers: The study may assist environmental health personnel in identifying possible sanitation-related factors associated with bacterial contamination. Information about the bacteriological quality of selected water sources may support environmental inspection, public education, and recommendations for improved sanitation around boreholes and household water facilities.

Water suppliers and borehole operators: The findings may help water suppliers and borehole operators appreciate the importance of proper borehole construction, maintenance, protection from contamination, and periodic microbiological testing. Ewelike et al. (2022) demonstrated that borehole water in selected communities in Owerri West may contain significant bacterial contamination, reinforcing the importance of monitoring groundwater sources.

Government and policymakers: The findings may contribute evidence relevant to local water safety planning, environmental sanitation, and the protection of public water supplies. Such information may help inform decisions concerning water quality monitoring and community awareness programmes.

Researchers and students: The study may provide baseline information for subsequent investigations into drinking-water contamination, bacterial distribution, household storage practices, and waterborne disease prevention. It may also provide a basis for comparing water quality across different communities and water source types in Imo State.

1.7 Scope of the Study

The study focuses on the bacteriological assessment of selected boreholes and household water sources in Owerri Municipal, Imo State.

The geographical scope is limited to the selected sampling locations within Owerri Municipal. The study population comprises the selected borehole and household water sources from which water samples will be collected.

The bacteriological scope includes the determination of total heterotrophic bacterial counts, coliform counts, and the isolation and identification of selected bacterial organisms using appropriate laboratory methods. The results will be compared with applicable drinking-water microbiological standards, particularly those concerning faecal indicator organisms.

The public health component will consider the potential implications of detected bacterial contamination and, where relevant information is collected, its relationship with source characteristics and household water-handling practices. The study will not independently establish the incidence of waterborne disease among residents unless epidemiological data are collected as part of the approved research design.

1.8 Limitations of the Study

The study may be limited by the number of water samples collected, the availability of laboratory materials, the cost of microbiological investigations, and the geographical coverage of the selected sampling locations.

Water quality may also vary according to rainfall, season, groundwater conditions, sanitation practices, and the frequency of water collection. Consequently, samples collected during a particular period may not fully represent the bacteriological quality of the sources throughout the year.

Another limitation is that conventional bacteriological culture methods may not detect every microorganism present in water, particularly organisms that are difficult to cultivate under routine laboratory conditions. Furthermore, the detection of indicator organisms does not identify every possible pathogen, and their absence does not establish that water is free from all microbiological hazards (WHO, 2022).

These limitations will be addressed, where possible, through aseptic sample collection, appropriate transportation and processing, standardised laboratory procedures, adequate sample documentation, and cautious interpretation of the results.

1.9 Operational Definition of Terms

Bacteriological assessment: The laboratory examination of water to determine bacterial counts, detect indicator organisms, and identify selected bacterial isolates.

Drinking water: Water intended for human consumption, including water used for drinking and preparing food.

Borehole water: Groundwater obtained through a drilled borehole for domestic or other purposes.

Household water source: A source from which a household obtains water for drinking and other domestic activities, or a household supply point from which water is collected for analysis.

Total heterotrophic bacterial count: An estimate of viable bacteria capable of growing under the specified culture conditions used in the laboratory procedure.

Total coliform count: The measured number of coliform bacteria detected in a water sample using the specified analytical method.

Faecal contamination: The introduction of human or animal faecal material or associated microorganisms into water.

Indicator organism: A microorganism, such as Escherichia coli, whose detection provides evidence relevant to the assessment of microbial water quality.

Bacterial isolate: A bacterial organism recovered from a water sample and subjected to identification using appropriate laboratory methods.

Public health implications: The potential consequences of the observed bacteriological findings for human health, including possible exposure to microorganisms associated with waterborne infections.

Water quality standard: An established microbiological criterion used to evaluate the suitability of water for its intended use.

Water source characteristics: Features of a water source, such as its type, physical protection, surroundings, maintenance, and proximity to potential contamination sources.

Project – Bacteriological Assessment of Drinking Water and Its Public Health Implications. A Study of Selected boreholes and household water sources in Owerri Municipal, Imo State