Department of Integrated Science
College of Education, Katsina-Ala.
In order to ascertain water quality for human consumption, major and minor ions were evaluated in sachet water supplied in Katsina-Ala metropolis. Standard methods were used for determining chemical and physical characteristics of the water samples. Cu, Fe, Pb, Ni, CN, Cd, Cr, Ba and Mn contents of the drinking water samples were determined by atomic absorption spectrometry. Multiple tube method and biochemical assays were also used for analyzing the water samples. The observed values were compared with standard values given by Nigerian standard for drinking water quality and the World Health Organization for potable water. The quality of the analyzed water samples was found fit for human consumption.
Keywords: Sachet water, water quality, contaminated water, drinking water, microorganisms
Water is the nucleus of all life – meaning that it is a resource for the flora and fauna of our earth and a fundamental necessity for human life. This means that without adequate supply of pure water, there is no hope of improving human health. Natural water contains different types of impurities due to increased human population, industrialization, use of fertilizers in agriculture and other human activities. Water is highly polluted with different harmful contaminants. Also, aquatic systems become impure through different ways such as earth crust temperature, soil erosion and several human activities (Edema, Atayese, and Bankole, 2011). The contaminants or pollutants in natural water can be microbial and chemical in origin (Omalu, Mohammed, Olamide, Ayanwale, Adeniran and Gbise, 2012). Microbial contaminants in drinking water affect human health more than chemical contaminants they do not require long term exposure whereas the latter require long term exposure (Krishnan, Dharmaraj and Kumari, 2007). Nonetheless, chemicals in water supplies can cause very serious problems. Two million of children’s death occur every year due to contaminated water (WHO, 2007). Safe drinking water is a basic need for human development, health and well-being; it is internationally accepted by human rights (Krishnan, Dharmaraj and Kumari, 2007). About 1.1 billion of the world’s population doesn’t have access to improved water supply, while 2.4 billion does not have access to improved sanitation facility (Omalu et al., 2012). According to Ilyas, Gilani and Bhatty (2008), almost 50% of the population in the developing countries is suffering from water borne illnesses, addition 1.8 million children who die from diarrhea each year, during which 443 million school days are lost due to water-related illnesses.
The intake of impure water can have devastating effects on our health as unsafe drinking water is the cause of many microbial diseases with serious complications in healthy and unhealthy individuals. The WHO estimates that 80% of all disease is in some way connected with contaminated water (United Nations, 2003).
The introduction of sachet water in Nigeria was to provide safe, hygienic and affordable instant drinking water to the public, to curb the menace of water related infections and to supplement the inadequate supply of tap water to the public. Although this is a major breakthrough to salvage the problem of water shortage, current studies in many places seem to suggest that sachet drinking water could be a route of transmission of diseases. The intervention of NAFDAC helped in curtailing the indiscriminate production of sachet water in Nigeria, although it has not actually stabilized the quality of this water.
The availability of water has become a critical and urgent problem in Nigeria. Unsafe water is a global public health threat, placing persons at risk for a host of diarrheal and other diseases as well as chemical intoxication. According to the World Health Organization (WHO 2007) 2.3 billion people suffer from diseases caused by contaminated water. Each year 1.8 million people die from diarrheal diseases, and 90% of these deaths are of children under 5. Besides causing death, water-related diseases also prevent people from working and leading active lives. The problems associated with the lack of adequate and quality water resources in Nigeria threaten to place the health of about 40 million people at risk. The increased population is demanding immediate attention for the provision of safe and potable water. The recent introduction of sachet water to consumers was to provide safe, hygienic and affordable instant drinking water to the public. Although this is a laudable idea, current trends seem to suggest that sachet drinking water could be a route of transmission of enteric pathogens.
Government negligence in the provision of basic amenities/infrastructure has left the Nigerian water-drinking public at the risk of serious water shortage. The public has therefore taken to several adaptive measures of alleviating this stress. One of these is the dependence on sachet water, popularly referred to as “pure water”. Although easy to serve and the price affordable, it has devastating effects on the health of the populace, if it is not pure. Studies have been carried out on water samples to ascertain the presence of heterotrophic bacteria, indicators of faecal contamination (total coliforms, faecal coliforms and enterococci), the physical and chemical properties and the concentration of metals in sachet water in some parts of the country.
Since the major source of our drinking water is sachet water, the understanding of the overall quality of the water in our markets is of paramount importance. It is in view of the above problem that the researcher is prompted to make an assessment of the quality of sachet water and tap water consumed by people in Katsina-Ala metropolis in Katsina-Ala Local Government Area of Benue state.
Population explosion and the inadequate supply of water from the Katsina-Ala Water Board have caused serious shortage of potable water in Katsina-Ala Township. The people in this town have no option other than consuming the available (that is sachet water). Health problems associated with the drinking of sachet water have aroused public concern.
Objectives of the Study
The overall objective of this research was to investigate the quality of six (6) sachet water samples in Katsina-Ala metropolis – namely, Our Faith, Zema, Tulip, Bana, Solace and Scantly and suggest strategies for improving their quality by:
- testing the quality of sachet-water samples;
- comparing the quality of sachet water with that of international water standards.
- suggesting ways of monitoring and improving sachet water quality.
- determining bacterial loads and contaminants in sachet water.
Materials and Methods
Three water sachets of 500 ml each from the six brands of sachet water were purchased from roadside and market vendors in Katsina-Ala and analysed for physico-chemical and bacteriological characteristics.
The collected samples were analysed for major physical and chemical water quality parameters like pH, Electrical conductivity (EC), Total Dissolved solids (TDS), total hardness (TH), Ca2+, Mg2+, Conductivity, Colour, Turbidity, odour, Sodium, Potassium, Alkalinity, heavy metals (Iron, Lead, Copper, Chromium, Cadmium, Nickel, Zinc, Mercury, Cyanide and Arsenic) Nitrate/Nitrite, Fluoride, Chloride, Manganese, Aluminium using Standard methods for the examination of water and wastewater.
The pH was determined using modern digital pH-meter after the meter was calibrated with standard buffers of pH 4.0 and 7.0; Alkalinity was determined by titration method with corresponding indicator; Chloride was measured by precipitation method; EDTA titration method was used for the determination of the Total Hardness (TH) as well as calcium and magnesium hardness; Dissolved oxygen (DO) was determined by the modified Winkler’s method (American Public Health Association,  and Chaturvedi, and Sankar, ). Chemical oxygen demand (COD) was carried out by using titration method whereas; the electrical conductance (EC) was found out by E.C. meters (Chaturvedi, and Sankar, 2006).
The samples were analyzed for heavy metals using air/acetylene atomic absorption spectroscopy UNICAM 969 model with the use of prepared standards for Fe, Cu, Cd, Zn, Pb, Cr, Ar, Hg and Ni.
The main purpose of bacteriological analysis of water was to determine the extent of purity. There are three groups of bacteria present in abundance in the intestinal tract of man and animals-the coliforms, the anaerobic lactose-fermenting spore formers and the faecal streptococci. Of these three groups, the coliform organisms are more closely related to the intestinal pathogens (typhoid, dysentery and paratyphoid organisms) and hence are affected by storage, sedimentation, chlorination and other natural or induced processes of purification to approximately the same degree. The sachet water samples were tested for the three groups of bacteria mentioned above.
Culture media: All apparatus (glass wears) used were thoroughly washed with detergent and rinsed several times with the water, glass wares were then air dried before sterilization in an oven at 160 for 2 hours. Media used included Nutrient agar, Salmonella/shigella agar, Eosine methylene blue agar and MacConkey agar. All the media used were sterilized by autoclaving at 121 for 15 minutes and prepared according to the manufacturer’s specification. Presumptive tests were performed using the multiple tube method. After inoculation of the media with the samples, the culture tubes were incubated at 37 for 2 hours before transferring them to 44 incubator for 18 hours. After incubation, the cultures were inspected for changes in colour and gas production. Those showing growth with or without gas production were noted. Those showing no changes in colour were re-incubated for additional 24 hours. The tubes showing changes in colour were counted and the MPN count was expressed per 100 ml of sample as per the MacGrady’s Probability Table. The cultures that showed growth were also sub-cultured on the MacConkey agar plates to obtain discrete colonies to facilitate easy isolation and identification of the predominant organisms.
Results and Discussions
Physico-chemical Properties of the Water Samples
Physico-chemical properties of the six different water samples are shown in Table 1. All the samples were found to be colourless and odourless and not turbid.
The overall pH value ranged from 6.89 to 8.32. This range falls within the Nigerian standard for drinking water quality range and its value is within the permissible limit of pH in water that is 6.5 to 8.5 (Standard Organization of Nigeria (SON), 2007). According to Lenntech (2017), the recommended pH range for drinking water by World Health Organization (WHO) is between 6.5 and 8.5. A higher value of pH above 8.5 will have serious effects on human health.
The Measurement of EC is used to determine the presence of ions in aqueous solution. Higher values of conductivity indicate higher concentration of dissolved ions. The EC for the water samples ranged between 250 and 358 mho, which falls within the SON range. The EC values of these samples were below the standard value and did not contain much ionized metals especially those that could pose serious health hazards.
Alkalinity refers to the capability of water to neutralize acid, which is really an expression of buffering capacity. The value of alkalinity for the six water samples fell between 56.4 and 78.3. All values were within the Nigerian standard for drinking water quality approved range (SON, 2007).
Total Hardness (TH) of water is caused by the presence of multivalent metallic cations and is largely due to calcium, Ca++, and magnesium, Mg++ ions. Hardness is reported in terms of CaCO3. Hardness is the measure of capacity of water to react with soap, hard water requiring considerably more soap to produce lather. It is not caused by single substance but by a variety of dissolved polyvalent metallic ions, predominantly calcium and magnesium cations. The desirable limit for TH is 150 mg/L in potable water as per Nigerian standard for drinking water quality (SON, 2007). TH value for the four water samples varied from 54.5 up to 75.3 mg/L, which fell within Nigerian standard for drinking water quality range. The water containing excess hardness is not fit for drinking purposes and also not desirable for even domestic purposes. The analyzed water samples indicated that they were all soft.
Magnesium was not detected in the five water samples. The concentration of magnesium in one of the water samples was 0.10 mg/L. The permissible Mg-content in drinking water according to SON (2007) is 0.20 mg/L, thus indicating that all the analyzed six water samples possessed values that fell within the Nigerian standard for drinking water quality.
Chloride is one of the major inorganic anions in water. In potable water, the salty taste is produced by the chloride concentrations which is variable and dependent on the chemical composition. There is no known evidence that chlorides constitute any human health hazard. For this reason, chlorides are generally limited to 250 mg/L (SON, 2007) in supplies intended for public use. The chloride content of the tested water samples fell within the acceptable value of the Nigerian standard for drinking water quality.
Table 1: Physico-Chemical properties of the sachet water samples
|S/N||Samples||Turbidity (mg/L)||pH||EC (us/cm)||Alkalinity (mg/L)||Total Hardness (CaCO3Mg/L)||Magnesium (mg/L)||Sulphate (mg/L)||Chloride (mg/L)||Fluoride (mg/L||Nitrate (mg/L)||Nitrite (mg/L)|
The major physiological effects resulting from the ingestion of large quantities of sulfate are catharsis, dehydration, and gastrointestinal irritation. Water containing magnesium sulfate at levels above 600 mg/L acts as a purgative in humans. The presence of sulfate in drinking water can also result in a noticeable taste. The acceptable value for the concentration of sulfate according to the Nigerian standard for drinking water quality is approximately 100 mg/L.
Traces of fluorides are present in many waters. Higher concentrations are often associated with underground sources. In groundwater, fluoride concentrations vary with the type of rock that the water flows through but do not usually exceed 10 mg/L. The presence of large amounts of fluoride is associated with dental and skeletal fluorosis. Acceptable value by the Nigerian standard for drinking water quality is 1.5 mg/L. Values for all the six brands of sachet water fell within the Nigerian standard for drinking water quality values (SON, 2007).
Nitrates generally occur in trace quantities in surface waters but may attain high levels in some ground waters. The presence of nitrite in water is either due to oxidation of ammonium compounds or due to reduction of nitrate. It can be toxic to certain aquatic organisms even at a concentration of 1 mg/L. In excessive limits, it contributes to the illness known as methenoglobinemia in infants. All the analyzed samples fell within the Nigerian standard for drinking water quality acceptable value of 50 mg/L. In the analysed water samples, the concentration of nitrate was below the permissible criteria. The reduced concentration of nitrate might have been due to the removal of nitrate salt during the filtration process.
The nitrite concentration of all the analyzed samples fell within the acceptable Nigerian standard for drinking water quality value of 0.2 mg/L.
Heavy metal concentrations of the water samples are shown in Table 2. Copper, Cadmium, lead, Chromium, Arsenic, Mercury, barium, manganese, cyanide and Nickel were not detected in all the six brands of the sachet water samples. The concentration of zinc and iron did not exceed the acceptable limit by Nigerian standard for drinking water quality.
Table 2: Heavy Metals Concentration of the Sachet Water Samples in mg/L
|Samples||Zema||Barna||Tulip||Solace||Scantly||Our Faith||SON (2007)
n.d– not detected.
Bacteriological Quality of the Water
The bacteriological quality of the water samples is shown in Table 3.
Table 3. Bacteriological Quality of the Water
|Samples||Zema||Barna||Tulip||Solace||Scantly||Our Faith||SON (2007)
The bacteria species analysed in water samples were E-coli, facceal streptococci, clostridium, Perfringens and total coliform. These were completely absent in the sample. The termination of microbial life in the analysed water sample is due to chlorination. According to Eddy and Udoh (2006) the disinfection action of HOCl is pH dependent and functions best at pH range of 6.0 to 8.5. The measured pH of the water samples fell within this range (Table 1). From the point of view of bacteriological quality of water, it is desirable and permitted that E.coli and coliform bacteria should not be present in water meant for consumption (Alaanyi and Wachin, 2009). The bacteriological quality of the water confirmed that the water is fit for drinking.
Water is indispensable for life. The basic human physiological requirement for water is about 2.5 litres per day. This drinking water should be free from chemical as well as microbial contaminants, since the potential of contaminated water to transmit disease is very high. However, access to potable water in Katsina-Ala has been a big problem. The introduction of sachet water to consumers was to provide safe, hygienic and affordable instant drinking water to the public.
The primary objective of monitoring drinking water was to protect the health of the community by preventing the spread of water-borne diseases. The concentrations of investigated parameters in the sachet water samples from Katsina-Ala were within the permissible limits of the World Health Organization drinking water quality guidelines and SON (2007) and therefore fit for human consumption.
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