Comparative Study Of Physicochemical Analysis Of Borehole Water And Sachet Water

1.0 Introduction

Water is a universal solvent, which consist of hydrogen and oxygen atoms. Chemically, it could be defined as a chemical substance with two atoms of hydrogen and one atom of oxygen in each of its molecules; hence the molecular formula is H2O. It is formed by the direct reaction of hydrogen with oxygen;

2H2 + O2 2H2O

Water is colourless, odourless and tasteless liquid in its pure form. It is an inorganic substance that occurs in three states; liquid gaseous and solid states1. Water covers 71% of the earth surface. On earth , it is found mostly in oceans and other large water bodies with 1.6% of water below ground in aquifers and 0.001% in the air as vapour clouds (formed from the solid and liquid water particles suspended in air), and precipitation2. Oceans hold 97% of surface water, glacier and polar ice cap 2.4% and other land surface water such as rivers, lakes and ponds 0.6%. A very small amount of the Earths water is contained within biological bodies and manufactured products.

Water on earth moves continually through a cycle of evaporation, transpiration, precipitation and runoff, usually reaching the sea. Overland, evaporation and transpiration contributes to the precipitation. Clean and fresh drinking water is essential for human and other life forms. Access to safe drinking water has improved steadily and substantially over the last decades in almost every part of the world3, 4. There is a correlation between access to safe water and GDP, per capita5. However, some observers have estimated that by 2025 more than half of the world population will be facing water-based vulnerability6.

As water is heated from OOC, it contracts until 4oC is reached and then begins the expansion which is normally associated with increasing temperature. The viscosity of water decreases ten folds as the temperature is raised from OOC to 100 OC, and this also is associated with the decrease of ice like character in the water as the hydrogen bonds are disrupted by increasing thermal agitation. The electrical conductivity of water is at 1,000,000 times larger than that of most other non-metallic liquids at room temperature. The current in this case is carried by ions produced by the dissociation of water according to the reaction;

H2O H+ + OH-

These products recombine completely to form water vapour, also undergoes most of the chemical reactions of liquid water and at very high concentration even shows some of the unusual solvents properties of liquid water. Above 3740C, water vapour may be compressed to any density without liquefying, and at a density as high as 0.4glcm3, it can dissolve appreciable quantities of salt7.

1.1 Sources Of Water

Water naturally exists in three main sources; rain water, ground water and surface water.

Rain water is naturally the purest source of water but as it gets down it absorbs compounds from the atmosphere. Its main components are chlorides, nitrates, sulphates, sodium, potassium and ammonia. The concentration can vary from 0.1 to 10uglml. The rain can be collected from roofs and prepared water sheds which could assist in polluting and making it one of the most unfit sources of water for drinking8.

Ground water are said to have emanated from the melting of meteoric water (rain, snow, and hailstone), into the ground, they have served as source of domestic water supply. It offers cheaper and purer supply. The main ionic components are chloride, nitrate, sulphates, potassium, sodium and calcium. This includes natural springs, wells and boreholes9. As it percolates into the earth it is subjected to some purification actions by the numerous chains of pervious and impervious rock strata or layers. Because of the disintegrating and dissolving power of water, it dissolves some of the rocks which make up the earth layers making it to have impurities like oxides, nitrate, sulphates, calcium, iron, magnesium9. Some level of purity is achieved on turbidity, colour, odour and taste. It reaches surface through wells, shafts, springs, borehole.

The oceans hold about 97% of earth’s water. More than 2% is locked up in ice in the polar caps, and over 75% of the fresh water of the world is ice of the 1% of the liquid fresh water. Some is ground water at depths of over 1000 feet and impractical to obtain, and only the very small difference, possibly 0.6% of the total water of this planet is ever available to man as it cycles sea to atmosphere to land to sea.

Surface water includes streams, ponds and lakes, its main ionic compounds include chlorides, nitrates, sulphates, magnesium and calcium. The concentration of components here are more than those in rain water and ground water. Sea water could be considered as surface water. The salt content in it is so much that it cannot be used as drinking water because it would take the body a lot of work to flush out excess salt before usage for metabolism, it is also inadequate in the machinery use as it rust machines, it kills most crops frequently carry suspended solids10.
Water can dissolve many different substances giving it different taste and odour. In fact, humans and other animals have developed senses to be able to evaluate the portability of the putrid swamps; and favour the pure water of the mountain, spring, and aquifer. Humans also tend to prefer cold water rather than lukewarm, as cold water is likely to contain fewer microbes. The pleasant taste associated with spring water or mineral water is derived from the minerals dissolved in it, as pure water is tasteless.

1.2 Importance Of Water

Water is an indispensable rain material for a multitude of domestic and industrial purpose. Water is the most abundant material, its cheap production with less than 500ppm impurities will be more important to the world than atomic energy, as we all know it today. Water plays an important role in the world economy as it functions as a solvent for a wide variety of chemical substances and facilities industrial cooling and transportation. Approximately 70% of fresh water is consumed by agriculture11.

Domestic uses of water includes; cooking, washing of clothes, cars, dishes, to shower, flushing away of wastes and drinking. The human body contains 55% to 78% water depending on body size12. To function properly, the body requires between one and seven litres of water to avoid dehydration; the precise amount depends on the level of activity, temperature, humidity and other factors. Most of these are injected through foods or beverages other than drinking water directly. It is not clear how much water intake healthy people need, though most advocates agree that 6-7 of glasses of water daily is the minimum to maintain proper hydration13.

Water is used for fighting wildfires. Water has a high heat of vaporization and is relatively inert, which makes it a good fire extinguishing fluid. The evaporation of water carries heat away from the fire. However, water cannot be used to fight fires of electric equipments because impure water is electrically conductive or of oils and organic solvents, because they float on water and the explosive boiling of water tends to spread the burning liquid. Use of water in fire fighting should also take account the hazards of a stream explosion, which may occur when water is used on very hot fires in confined spaces, and of a hydrogen explosion, which may react with water, such as certain metals or hot graphite, decomposed the water producing hydrogen gas.

Water is used in biochemical processes, it is central to photo synthesis and respiration. Photosynthetic cells use the sun’s energy to split off water molecule (photolysis of water) to form hydrogen and oxygen.

2H2O 4H + + 4e- + O2

Hydrogen is combined with CO2 (absorbed from air or water) to form glucose and released oxygen. All living cells use such fuels and oxidized the hydrogen and carbon to capture the sun’s energy and reform water and CO2 in the process (cellular respiration). Water is also central to acid-base neutrality and enzyme function. An acid, a hydrogen ion (H+, that is a proton) donor can be neutralized by a base, a proton acceptor, such as hydroxide ion (OH-) to form water. Water is considered to be neutral, with a pH (the negative log of the hydrogen ion concentration) of 7. Acids have pH values less than 7 while bases have values greater than 7.

In agriculture, the most important use of water is for irrigation, which is a key component to produce enough food. Irrigation takes up to 90% water withdrawn in some developing countries14 and significant proportions in developed countries, (United State 30% of fresh water usage is for irrigation15).

Water is widely used in chemical reactions as a solvent, dissolving many ionic compounds. In organic reactions it does not dissolve the reactants well and is amphoteric (acidic and basic) and nucleophilic.

In recreation, water can be used for many purposes as well as for exercising and for sports. Some of these include swimming, boating, surfing and diving. In addition, some sports like ice hockey and ice-skating are played on ice. Lake sides, beaches and water paths are popular place for people to go, relax and enjoy recreation. Humans also use water for snow sports like sledding, snowboarding, which requires the water to be frozen.

Industrial uses of water includes; cooling of machinery in power plants, condenser cooling, sanitary services and for boilers. Many industrial processes rely on reactions using chemicals dissolved in water, suspensions of solids in water slurries or using water to dissolve and extract substances.

Water is used in power generation. Hydro-electricity is electricity obtained from hydropower. Hydroelectric power comes from water driving and water turbine connected to a generator. Hydroelectricity is low-cost, non-polluting, renewable energy source. The sun supplies the energy. Heat from the sun evaporates water, which condenses as rain at higher altitudes from where it flows down. Pressurized water is used in blasting and water jet cutters. Also very high-pressure water guns are used for precise cuttings. It works very well; it is relatively safe and not harmful to the environment. It is also used in the cooling of machinery to prevent overheating as in vehicle radiators.

1.3 Water Pollution

Water pollution is the contamination of water bodies such as lakes, rivers, oceans and groundwater. All water pollution affects organisms and plants that live in these water bodies and in almost all cases the effect is damaging either to individuals, species or population or also to the natural biological communities. It occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful constituents.

The point sources of water pollution include waste generated by human settlements, domestic, commercial and industrial activities and the precipitation of atmosphere pollutants. Water pollutants types can be categorized into the following;

i. Physical pollutants:

They include; silts, clay, discarded objects, weeds, decaying organic matter, which generally affect the aesthetic quality of surface waters.

ii. Chemical pollutants:

They are non-biodegradable toxic heavy metals such as lead, cadmium and mercury, as well as persistent and hazardous organic pollutants such as pesticides, phenols and polynuclear aromatic hydrocarbons.

iii. Microbial pollutants:

These pollutants arise from the discharge of effluents from domestic sources and manufacturing industries into surface water. Faecal contaminants can also lead to microbial pollutants.

iv. Radioactive pollutants:

These include substances or effluents carrying such substances containing radioisotopes such as radium 226, strondium 90 and caesium 13716.

Other sources of pollution include petroleum hydrocarbons (fuels like gasoline, diesel fuel, jet fuels and fuel oil) and lubricants (motor oil) and fuel combustion by-products from storm, water runoff. Inorganic water pollutants include acidity caused by industrial discharges especially sulphur dioxide from power plants, heavy metal from motor vehicles. Also Fertilizers containing nutrients (nitrates and phosphates), which are found in storm, water runoff from agriculture, as well as commercial and residential use.

Control Of Water Pollution

Forms with large livestock and poultry operations such as factory farms are called concentrated animals feeding in the U.S and are being subjected to increasing government regulation. Animal slurries are usually treated by containment in lagoons before disposal by spray or trickle application to grass land. Constructed wetlands are sometimes used to facilitate treatment of animal wastes, as anaerobic lagoons. Some animal’s slurries are treated by mixing with straw and composted at high temperature to produce bacteriological sterile and friable manure for soil improvement.

Nutrients (nitrogen and phosphorous) are typically applied to farmland as commercial fertilizer; animal manure; or spraying of municipal or industrial wastewater effluent. Management plans to reduce excess application of nutrients, to minimize pesticides impacts, farmers may use integrated pest management (IPM) techniques (which can include biological pest control) to maintain control over pests, reduce reliance on chemical pesticides and protect water quality. Thermal pollution from run-off can be controlled by storm water management facilities that absorb the run-off or direct it into ground water, such as bio retention systems and infiltration basins.
Pollution prevention practices include low impact development techniques; installation of green roofs and improved chemical handling (e.g. management of motor fuels and oil fertilizers and pesticides).

1.4 Water Quality

The importance of high quality water cannot be over-emphasized as it sustains human life and maintains health. Most waters, before they reach the consumer, have been exposed to greater or lesser amount of contamination, but in the majority of case, they have also undergone a more or less complete purification by natural agencies17.

The impurities liable to be found in water vary considerably in quantity and type. The kind of impurity to be expected in a water supply depend on the type of supply whether or not the water has been for long in the ground in contact with soluble minerals, whether or not it has been exposed on surface to organic pollution18.

Water in its natural state may not be pure because it is a universal solvent with the ability to dissolve numerous chemicals and to carry a lot of impurities that may predominantly come from man’s socio-economic and technological activities may be injurious, pathogenic or toxic with deleterious health consequence to humans if tolerable limits are exceeded19.

Domestic water is the water used for household and sanitary needs as well as urban, industrial and municipal requirements. The water should be harmless to the health of man, have proper organopelptic properties and be suitable for domestic uses. The standard of water in Nigeria should be in line with the World Health Organization (WHO) standard.

Water delivered to the consumer should be clear, odourless, tasteless and colourless. It should contain no pathogenic organisms and be free from biological forms, which may be harmful to human health. Waters are considered of doubtful quality unless proven otherwise. It is therefore important that drinking water be monitored to ascertain the level and nature of pollution. Any information derived would subsequently quid in determining the type and degree of treatment required to make the water potable and to guarantee health and safety20.

1.5 Portable Water

Water to be used for human consumption must be meet certain requirements. It must be free of all disease causing microorganisms, low in concentration of compounds that are acutely toxic or that have serious long term effect on heath. Ideally water for drinking should be clear, free of odour and compound that can cause colour or taste.

Drinking water from the ground is obtained by drilling boreholes and shallow wells through the existing water table to form a well point. In certain regions of southern Africa, as the water percolates through the soil, harmful physical, biological and chemical constituents (e.g. fine suspended matter, faecal coliform and fluoride) become contained in the water making it unsuitable for human consumption.

The quality of drinking water has attracted great attention worldwide because of implied public health impacts. Sachet packaged drinking water is very common in Nigeria. It is often found as a major source of water at food canteens and sold by many food vendors in the country. The majority of the population consume it, hence the need to ascertain the qualities of sachet and borehole water in order to safeguard the health of consumers. Many common and widespread health risks have been found to be associated with drinking water in developing countries, a large percentage of which are of biological origin21. Unsafe water, poor sanitation and good hygiene have been reported to rank third among the 20 leading risk factors for health burden in developing countries including Nigeria22.

The guidelines for drinking water quality (W.H.O) are intended for use by countries as a basis for the development of national standards which if properly implemented will ensure the safety of drinking water supplies23.

1.6 Objectives Of The Work

It is of most importance that any water sample intended to be used is properly analyzed to determine its quality and to know the extent to which it should be treated. This analysis is necessary because the bulk of water supplied to the public for domestic uses or industrial purposes entail that most probably, they will have their different quantities, hence the needs to determine the quality of each sample.

The main purpose of this work is to ascertain the quality of borehole water and sachet water from Owerri Municipal, Imo State by determining the physiochemical parameters of the waters in order compare both water and ascertain the one that have more portability for human consumption.

1.7 Sampling

Sampling technique must be considered for any analysis. The accuracy of the analysis depends on proper sampling. Sampling is simply collection of materials. Precautions should be taken during sampling and this includes;

1. The container should be clean.
2. Tin and steel containers should not be used as they cause corrosion.
3. Samples should be labelled accurately.
4. Water from tap should be carefully flushed/pumped before collection and tap shouldn’t touch containers to avoid contamination.
5. Volume of water should be large enough for accurate analysis.