Water is one of the indispensable resources for the continued existence of all living things including man. The provision of an adequate supply of safe drinking water was one of the eight components of primary health care identified by the International Conference on Primary Health care in 1978. This study investigated the bacteriological quality of sachet-packed water in Imo State, Nigeria. A total of five sachet water collected around Imo State University premises where examined for registration number, manufacturing date, expiry date and net volume (cl).

Physiochemical analysis carried out showed that these sachet waters where in accordance with the World Health Organization (WHO) Standard. The sachet waters cultured on bacteriological media showed the presence of coliform bacteria and other pathogenic bacteria. The bacteria isolate form the water samples are; Salmonella species, Coliform species, Escherichia coli, and Enterobacter species.

Results showed that 100% of the packaged water samples examined were either untreated or produced under unhygienic conditions. High aerobic colony counts in the order of 106 were recorded from all of the samples examined. The findings show that 90% of packed pure water sold in the country are not fit for human consumption and are hazardous to health. This calls for urgent attention by regulatory bodies and law enforcement agencies in the country.







Production and sale of sachet water, popularly called “pure water” in Nigeria, is presently a lucrative business, therefore many people are involved in the production and marketing of the product. Water is one of the most important as well as one of the most abundant compound on earth, and is vital to the survival of any organism (Tortora et al., 2002).Water in nature is seldom totally pure. Rainfall is contaminated as it falls to earth (Ajewole, 2005). The combustion of fossil fuel put sulphur compounds as being responsible for pollution of rain water by precipitation (Edema et al., 2001). However, water that moves below the ground surface undergoes natural filtration that removes most organisms. For this reason, water from springs and deep wells are generally of better quality than flowing water. Water related diseases continue to be one of the major health issue globally. The high revalence of diarrhoea among children and infants can be traced to the use of unsafe water and unhygienic practices (Omalu et al., 2010).  The most dangerous form of water pollution occur when fecal contaminants like Escherichia coli enter the water supply and also through the fecal-oral routes of transmission. Microbial contaminants in water supply are the sources of many diseases such as typhoid fever, cholera, bacillary dysentery and so on. Examples of such microbial contaminants are Salmonella spp., Shigella spp.,Vibrio cholerae, Escherichia coli (Edema et al.,2001; Tortora et al., 2002). Various opportunistic pathogens that occur naturally in the environment may cause disease in humans. Those who are at greater risk of infection are infants and young children, people whose immune system is suppressed, the sick and the elderly. In such individuals, drinking water containing large numbers of opportunistic pathogens can occasionally produce infections. Examples of such opportunistic pathogens are

Pseudomonas aeruginosa, Klebsiella spp., Areomonas spp., and certain slow growing Mycobacterium (WHO, 2001) in Nigeria, the National Agency for Food and Drugs Administration Control (NAFDAC) in association with the World Health Organization (WHO, 2001) has the responsibility of regulating the standard of drinking water. The agency has published guidelines for the production of sachet- packaged drinking water. Unfortunately most producers do not adhere to these guidelines (Onemano et al., 2003). Thus, this work is aimed at assessing the microbiological quality of sachet packaged water in three Local government areas in Ibadan.






The aim of this study is to evaluate the sterility of sachet water sold in owerri, particularly in Imo State University.


The objectives of this study are

  1. Isolation of organism from sachet water sold in Imo State University
  2. Identification of the isolates from sachet water sold in Imo State University

1.3 Significance of the study

Water analysis is the first step in determining the quality of the water you use in your home or commercial enterprise.  Water that is supplied to cities, towns and villages is tested on a regular basis by the local County or City Council. Well and surface waters are vulnerable to pollution and should be checked for pathogenic bacteria. The presence of Coliforms in water bodies indicates presence of pathogenic bacteria. Sachet water sold in Owerri is to be properly analyzed for pathogenic bacteria such as Salmonella spp. as this will help prevent once from drinking contaminated water.



1.4.1 Water Analysis

Microorganisms are natural components of streams, lakes, rivers and underground waters. These organisms have enormous impact on the process that occur in aquatic ecosystem such as carbon, nitrogen, and sulphur transformation. They can also have an impact on the quality of water by controlling the amount of oxygen and other elements in the and by causing diseases in aquatic organisms as well as humans. Microorganisms from other sources also are introduced into the aquatic environment as a result of pollution. The sources of water supply are usually water from any of these sources is treated to make it suitable for drinking. The aim of microbiological examination of water is to determine the sanitary quality and its suitability for general use. The sanitary quality of water is the relative extent of the absence of suspended matter, colour, taste, and unwanted dissolved chemical, bacteria indicative of faecal presence and other asthetically offensive objects or properties (Pipes, 2000). The major concern about the water quality is pollution by faecal materials and toxic chemical is called potable water. Potable water is unsafe for consumption. When fecal materials contaminate source of water supplies, they may contain pathogenic organisms which may cause epidemic outbreaks of cholera, typoid fever, bacillary dysentery, hepatitis or other diseases. Water borne pathogens are causative agents for many human diseases and their presence poses a potential threat to the human population. It is well known that water resources are subjected to frequent dramatic changes in microbial and chemical qualities as a result of the variety of activities on the watershed. For rural populations, the provison of reliable and clean water supplies is an important element in the quality of life. The microbial quality of drinking water is a cause of concern worldwide. A large percentage of ill health in less developed countries stems from lack of safe water adequate sanitation (Pipes, 2000).

Water analysis is therefore a standard routine procedure carried out by the sanitary microbiologists of the municipal water purification plant. The purpose of analysis of municipal water is to determine the raw water quality, the need for purification and possible changes during distribution (Pipes, 2000).

Microorganisms are natural components of lakes, rivers, underground waters and streams. These organisms are numerous and perform various functions in the aquatic systems. However, their presence in drinking water poses great risk to man and animals. Water sources could be perfectly clean in appearance, free from characteristics of odor and taste and yet is contaminated. It is well known and proven fact that water contaminated with sewage and other pollutants could cause disease. The degree of pollution and natural purification of water bodies can measure physically, chemically and biologically and no single yardstick is enough depending on the nature of the polluting substances and the uses the receiving body of water is to serve. Water is only safe for drinking (i.e potable) if it is free from disease producing microorganisms and chemical substances harmful to health. Microbiological examination of water is therefore a very useful and significant method of biological assessment of new or intermittent water pollution (Willey et al., 2008).

1.4.2 Microorganisms as Indicators of water quality

Indicator organisms are used as a proxy to monitor conditions in a particular environment, ecosystem, area, habitat, or consumer product. Certain bacteria, fungi and helminth eggs are being used for various purposes.

Types Indicator bacteria

Certain bacteria can be used as indicator organisms in particular situations. The presence of bacteria commonly found in human feces, termed coliform bacteria (e.g. E. coli), in surface water is a common indicator of faecal contamination. For this reason, sanitation programs often test water for the presence of these organisms to ensure that drinking water systems are not contaminated with feces. This testing can be done using several methods which generally involve taking samples of water, or passing large amounts of water through a filter to sample bacteria, then testing to see if bacteria from that water grow on selective media such as MacConkey agar. Alternatively, the sample can be tested to see if it utilizes various nutrients in ways characteristic of coliform bacteria (Pipes, 2000).

Coliform bacteria selected as indicators of faecal contamination must not persist in the environment for long periods of time following efflux from the intestine, and their presence must be closely correlated with contamination by other faecal organisms. Indicator organisms need not be pathogenic. Non-coliform bacteria, such as Streptococcus bovis and certain clostridia may also be used as an index of faecal contamination.

Indicator fungi

Penicillium species, Aspergillus niger and Candida albicans are used in the pharmaceutical industry for microbial limit testing, bioburden assessment, method validation, antimicrobial challenge tests, and quality control testing. When used in this capacity, Penicillium and A. niger are compendial mold indicator organisms (Ashbolt et al., 2016).

Molds such as Trichoderma, Exophiala, Stachybotrys, Aspergillus fumigatus, Aspergillus versicolor, Phialophora, Fusarium, Ulocladium and certain yeasts are used as indicators of indoor air quality.

Indicator helminth eggs

Identification and quantification of helminth eggs at UNAM University in Mexico City, Mexico. Helminth eggs (or ova) are a good indicator organism to assess the safety of sanitation and wastewater reuse systems for resource recovery because they are the most environmentally resistant pathogens of all pathogens (viruses, bacteria, protozoa and helminths) and the isolation and identification of pathogens in water is not the basis to determine the portability of water especially as regards its microbiological quality (Ashbolt et al., 2016). This is because

  • Pathogens may be present in very small numbers and are likely to escape detection by laboratory procedures
  • Pathogens are likely to enter water supply sporadically and may not survive for a long period of time
  • It takes 24 hours or longer to obtain results from a routine laboratory examination for pathogenic microorganisms.

If routine examination targets pathogenic organisms only, by the time the pathogens are isolated; many people would have consumed the water and would be exposed to those pathogenic microbes before any meaningful action could be taken to correct the situation. In practice therefore, Microbiologists use water testing procedures that do not depend on the isolation and identification of pathogenic organisms. Rather, tests are usually based on the findings of microorganisms whose presence indicate or show the possibility of the presence of pathogenic microorganisms. These kinds or organisms are referred to as indicator microorganisms (Ashbolt et al., 2016).

1.4.3 Characteristics of Indicator Organisms

Indicator microorganisms have some important characteristics which make them suitable for the purpose. These characteristics include:

  1. It is present in water and absent from unpolluted water
  2. Indicator organisms are present in water when pathogens are present
  3. The quantity of indicator organisms correlates with the amount of pollution
  4. It survives better and longer than the pathogens
  5. It is generally harmful to humans and other animals
  6. It has uniform and stable properties
  7. It can be easily detected by simple standard laboratory procedures

The organism that carry satisfies the requirement of an ideal indicator of fecal water pollution is Escherichia coli and is the organism that is mostly used. However, other bacteria that can also be used as pollution indicators include Streptococcus faecalis and Clostridium perfringes are normal inhabitants of the large intestine of humans and other animals. It has also been suggested waste into water can be used as indicators of pollution. Viruses that can be used include the coliform bacteriophages and reoviruses (Norwalk virus).

Escherichia coli and other coliform bacteria

The coliform bacteria are gram negative non sporing, facultatively anaerobic bacillus which can ferment lactose within 48 hours with the formation of acid and gas at 35OC. examples of coliform include  Escherichia coli, Klebsiella, Enterobacter, Hafnia, Serrati and Citrobacter.  Water bacteriologist usually consider any member of the Enterobacteriaciae which grows at 37OC and normally possesses the enzymes β-galactosidases as coliform (Chantran and Heartha, 2005).

Escherichia coli are a normal inhabitant of the human intestinal tract and other warm blooded animals and thus is regarded as a feacal type of coliform. Some members of the coliform group, for example Enterobacter aerogenes are widely distributed in nature and found in soil, water, grains and also the intestinal tract of human and other animals and other animals and are regarded as the non faecal coliform (Chandran and Heartha, 2005).

1.4.4 Water Pollution

Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater). This form of environmental degradation occurs when pollutants are directly or indirectly discharged into water bodies without adequate treatment to remove harmful compounds.

Water pollution affects the entire biosphere – plants and organisms living in these bodies of water. In almost all cases the effect is damaging not only to individual species and population, but also to the natural biological communities.

Water pollution is a major global problem which requires ongoing evaluation and revision of water resource policy at all levels (international down to individual aquifers and wells). It has been suggested that water pollution is the leading worldwide cause of deaths and diseases, and that it accounts for the deaths of more than 14,000 people daily. An estimated 580 people in India die of water pollution related illness every day. About 90 percent of the water in the cities of China is polluted. As of 2007, half a billion Chinese had no access to safe drinking water. In addition to the acute problems of water pollution in developing countries, developed countries also continue to struggle with pollution problems. For example, in the most recent national report on water quality in the United States, 44 percent of assessed stream miles, 64 percent of assessed lake acres, and 30 percent of assessed bays and estuarine square miles were classified as polluted. The head of China’s national development agency said in 2007 that one quarter the length of China’s seven main rivers were so poisoned the water harmed the skin (Wachman  and Richard, 2007).

Water is typically referred to as polluted when it is impaired by anthropogenic contaminants and either does not support a human use, such as drinking water, or undergoes a marked shift in its ability to support its constituent biotic communities, such as fish. Natural phenomena such as volcanoes, algae blooms, storms, and earthquakes also cause major changes in water quality and the ecological status of water.

Point sources

Point source water pollution refers to contaminants that enter a waterway from a single, identifiable source, such as a pipe or ditch. Examples of sources in this category include discharges from a sewage treatment plant, a factory, or a city storm drain. The U.S. Clean Water Act (CWA) defines point source for regulatory enforcement purposes (USGS, et al., 2000). The CWA definition of point source was amended in 1987 to include municipal storm sewer systems, as well as industrial storm water, such as from construction sites.

Non-point sources

Nonpoint source pollution refers to diffuse contamination that does not originate from a single discrete source. NPS pollution is often the cumulative effect of small amounts of contaminants gathered from a large area. A common example is the leaching out of nitrogen compounds from fertilized agricultural lands. Nutrient runoff in storm water from “sheet flow” over an agricultural field or a forest are also cited as examples of NPS pollution.

Blue drain and yellow fish symbol used by the UK Environment Agency to raise awareness of the ecological impacts of contaminating surface drainage

Contaminated storm water washed off of parking lots, roads and highways, called urban runoff, is sometimes included under the category of NPS pollution. However, because this runoff is typically channeled into storm drain systems and discharged through pipes to local surface waters, it becomes a point source.

Groundwater pollution

Interactions between groundwater and surface water are complex. Consequently, groundwater pollution, also referred to as groundwater contamination, is not as easily classified as surface water pollution (USGS et al., 2000). By its very nature, groundwater aquifers are susceptible to contamination from sources that may not directly affect surface water bodies, and the distinction of point vs. non-point source may be irrelevant. A spill or ongoing release of chemical or radionuclide contaminants into soil (located away from a surface water body) may not create point or non-point source pollution but can contaminate the aquifer below, creating a toxic plume. The movement of the plume, called a plume front, may be analyzed through a hydrological transport model or groundwater model. Analysis of groundwater contamination may focus on soil characteristics and site geology, hydrogeology, hydrology, and the nature of the contaminants.


The specific contaminants leading to pollution in water include a wide spectrum of chemicals, pathogens, and physical changes such as elevated temperature and discoloration. While many of the chemicals and substances that are regulated may be naturally occurring (calcium, sodium, iron, manganese, etc.) the concentration is often the key in determining what is a natural component of water and what is a contaminant. High concentrations of naturally occurring substances can have negative impacts on aquatic flora and fauna.

Water Pollutants

Major water pollutants are as follows:

  • Sewage – Sewage pollutants include domestic and hospital wastes, animal and human excreta etc. The sewage let off cause’s oxygen depletion, spread of diseases/epidemics.
    Metals – Metals like mercury are let off into water bodies from industries. Heavy metals like mercury cause poisoning and affect health causing numbness of tongue, lips, limbs, deafness, blurred vision and mental disorders.
  • Lead – Industrial wastes also lead to lead pollution. If lead enters the human body system in higher quantities it affects RBCs, bone, brain, liver, kidney and the nervous system. Severe lead poisoning can also lead to coma and death.
  • Cadmium – Source for cadmium pollution is industries, fertilizers. Cadmium gets deposited in visceral organs like liver, pancreas, kidney, intestinal mucosa etc. Cadmium poisoning causes vomiting, headache, bronchial pneumonia, kidney necrosis, etc.
  • Arsenic – Fertilizers are source for arsenic pollution. Arsenic poisoning causes renal failure and death. It also causes liver and kidney disorders, nervous disorders and  muscular atrophy, etc.
  • Agrochemicals like DDT – It is a pesticide. Accumulation of these pesticides in bodies of fishes, birds, mammals and man affects nervous system, fertility and causes thinning of egg shells in birds.
  • Bacteria, Viruses and Parasites – These are sourced from human and animal excreta, they are infectious agents.
  • Plastics, Detergents, Oil and Gasoline – They are a waste from industries, household and farms. They trigger organic pollution and is harmful to health.
  • Inorganic Chemicals – Inorganic chemicals like acids, salts, metals are a result of industrial effluents, household cleansers, and surface run-off and are injurious to health.
  • Radioactive Materials – Mining and ores processing, power plants,  weapons production and natural give rise to radioactive pollution like that of uranium, thorium, cesium, iodine and radon. Radioactive pollution causes serious health diseases to all organisms.
  • Sediments – Sedimentation of soil, silt due to land erosion and deposition causes disruption in ecosystem.
  • Plant Nutrients – Nutrients like nitrates, phosphates, and ammonium are let off from agricultural and urban fertilizers, sewage and manure. Excess of nutrients cause eutrophication and affect the ecosystem.
  • Animal Manure and Plant Residues – These substances in water causes increased algal blooms and microorganism population. This increases oxygen demand of water, affecting aquatic ecosystem. This is introduced into water due to sewage, agricultural run-off, paper mills, food processing etc.
  • Thermal Pollution – Temperature changes of water caused due to using water as cooling agent in power plants and industries causes increase in water temperature affecting the aquatic life.

Causes of Water Pollution

The contaminants that lead to water pollution include a wide variety of substance like chemicals, pathogens, temperature changes and discoloration.

  • Industrial activity causes huge water pollution. Wastes from factories are let off into freshwater to carry waste from plants into rivers. This contaminates water with pollutants like lead, mercury, asbestos and petrochemicals.
  • Sewage let off from domestic households, factories, commercial buildings are untreated in water treatment plants yet are disposed into the sea. Sewage containing flush chemicals and pharmaceuticals causes greater problems.
  • Solid waste dumping and littering of cardboard, plastics, glass, styrofoam, aluminium tins, etc., in water bodies.
  • Oil spills from tankers and ship travel causes oil pollution. Oil does not dissolve in water and forms a thick layer on the water surface.
  • Burning of fossil fuels and emissions from industries and motor vehicles causes formation of acidic particles in the atmosphere. These particles fuse with water vapor resulting in acid rain. Acid rain harms aquatic life.
  • Increase in water temperature is a result of global warming and thermal plants use water as cooling agents for mechanical equipments.

Other causes of water pollution: 

Detergents, by-productions of disinfection, food processing waste, insecticides, petrochemicals, debris from logging operations, volatile organic compounds, personal hygiene and cosmetic products, drug pollution, chemical wastes, fertilizers, heavy metals, and sedimentation are other causes of water pollution.

Effects of Water Pollution

Water pollution extensively affects health in humans and aquatic ecosystems.

  • Groundwater contamination causes reproductive and fertility disorders in wildlife ecosystems.
  • Sewage, fertilizer and agricultural run-off has nutrients, organic substances which lead to increase of algal bloom causing oxygen depletion. The lower oxygen levels affect the natural ecological balance of rivers and lake ecosystem.
  • Consumption and swimming in contaminated water causes skin diseases, cancer, reproductive problems, stomach ailments in humans.
  • Industrial effluents and agricultural pesticides accumulate in aquatic environments causing harm to aquatic animals and lead to biomagnifications. Heavy metals like mercury, lead are poisonous to small children and women. These chemicals interfere in the development of nervous system in fetuses and young children.
  • Rising water temperatures destroy aquatic ecosystem. Coral reefs are bleached due to warmer temperatures. Warmer waters forces indigenous water species to seek cooler water causing ecological shift of the affected area.
  • Littering by humans like plastic bags, clog and suffocate aquatic animals.
  • Water pollution causes soil erosion in streams, rivers and flooding due to accumulation.

Water treatment

Water supplies are usually obtained from surface waters (rivers, lakes and streams) and aquiters (underground layers of water being rocking) and sub-surface water called groundwater. Usually surface waters are more polluted than underground water sources. Water for public supply must be treated  to elimante pathogens and eliminate or decrease to safe levels any harmful substances which may be present. Water supplies such as deep wells that are relatively clean and free of contaminating require less treatment than those from surfaces laden with wastes (Dada et al., 2000).

Ground  water treatment

Water obtained from bore holes and springs is generally of good quality and may need little more than aeration, rapid sand filtration and disinfection. However, if the water contains nitrates there is need to either store the water for extended periods to permit denitrification or nitrate removal can be achieved by ion-exchanged processes (Chauvin, 2000).

Treatment of surface waters

Cities and municipals that source their raw water from streams, lakes and rivers needs to treat the water in order to eliminate pathogenic microorganisms as well as harmful chemicals. In many cities, there are public water works which treat and distribute water in the towns.

The treatment of water for distribution usually involves the following processes aeration, coagulation or flocculation, sedimentation, filteration and disinfection/chlorination (Chauvin, 2000).

The first step in the  treatment of water from surface water sources is the impoundment of the water in large reservoir such as dams or catchment basins where the water is allowed to stand long enough for the particulate matter to settle. These reservoirs are also referred to as sedimentation basins. The particles that settle out include sand and gravel. Sedimentation basins are mainly used when the water supply is highly turbid. A major problem of sedimentation is that growth of algae is encouraged and this can produce odours and flavours (Chauvin, 2000).

However this is usually controlled by pretreatment with copper sulphite (0.3ppm). Bacterial growth may also occur at the bottom process. Due to the aeration/oxygenation the biodeterioration of some synthesic detergents abd herbicides may occur.



Coagulation or flocculation

Many water works do not have storage reservoirs as discussed above. Both in water works that have reservoirs and those that don’t, the removal of humid substances (e.g. reduced iron and manganese and complex soluble organic compounds of natural origin) is necessary as their presence in water imparting a brown colour. Flocculation is employed for the clarification of water and involved the addition of small quantity of coagulant (5 to 70mg/l) of alum, or aluminum potassium phosphate. Alum cause materials still suspended in the water to coagulate, forming aggregates that strongly sink to the bottom. The clumps remove unwanted materials from the water including some bacteria and viruses as the settle out. To remove the flocs (clarification), the water is passed upwards through a floc blanket clarifier (a tank within which the flocs form a sludge blanket) below a layer of clarified water (Dada et a., 2000).


After the coagulation, the clarified water is filtered to removethe remaining suspended particles and microorganisms. Basically two types of filters are used namely rapid sand filters and slow sand filters.

  • Rapid sand filter: the rapid sand filter is suitable in filtering water containing only fine particles and dissolves substances. The rapid sand filters consists a bed of sand (grain size-1mm) which acts essentially as a mechanical sieve. Rapid sand filters are used in large water works and filters the water at a very fast rate. While using the rapid sand filters when the filterations rate falls, air is blown upwards through the sand to dislodge the particulates and this followed by water (back-washing) to remove the solids.
  • Slow sand filters: slow sand filters contains finer sand and the upper layer supports a biofilm of microorganisms (bacteria and algae which serve as biofilter) the slow sand filters acts as a mechanical sieve as well as effecting biological purification by mineralizing some of the dissolved organic matter and removal of some nitrogen and phosphorus. Slow sand filters can eliminate certain taste and odour causing substances and can reduce the levels of any cyanobacterial toxins which may be present (Dada, et al., 1990).


This involves the treatment of water with chlorine or other disinfectants to kill harmful bacteria, protozoa and viruses that may remain. Chlorination is done by bubbling chlorine gas through the tank until it reaches a concentration of 1-2ppm. Chlorine reacts with organic materials and therefore reduces or eliminates them (Dada  et al., 2000)