About 70% of the earth's surface is made up of water which is only a small fraction (about 0.02%) of the total water content of the earth. The remaining percentage of the earth's water is inaccessible, it is embedded in underground aquifers and some in the atmosphere as moisture (Straliler 1973).
Water is abundant in nature and is made up of two elements, hydrogen and oxygen. Water is the most popular solvent as it has the ability to dilute almost every chemical. Water also has a tremendous heat absorbency and plays an important role in the physiology of both flora and fauna (plants and animals) and also in their metabolic processes. Water takes part in many reactions including those with complex organic compounds like amino acids. It is vital in industrial and manufacturing activities and various agricultural aspects, especially irrigation.
Water is an essential natural as it is impossible for life to exist without it and most manufacturing industries cannot function. An essential prerequisite for the establishment of a stable community is the presence of a safe and reliable source of water. Historically, water scarcity has led to severe conflicts, migration and change in agricultural patterns. Therefore, the saying that "water is life" is a fact, thus its protection should be taken seriously.
Human activities often result in water pollution making such water unfit for use pollution is defined by Dix (1981) as a natural or induced change in the quality of water which renders it unsuitable or dangerous as regards foods, human and animal health, industry, agriculture, fishing or leisure pursuits. However, before the advent of industrialization, the degree of contamination of water by pollutants was low. New age activities like manufacturing processes have led to pollution of several water sources. A typical example is the location of chemical industries at riverbanks with influents released into the river, sewage disposal into water bodies, as is practiced in Lagos Lagoon, leaves streams and rivers polluted. Agricultural processes involving the use of fertilizers, herbicides and pesticides produce toxic substances that are transported as effluents into water courses and pollute water bodies similarly, textile industries emit waste water that contains organic dyes, which introduce different ions into water that can alter its composition.
Oil spill pollutes water bodies and forms a film on the water bodies and form a film on the water surface that cuts off oxygen supply. This leads to anaerobic conditions and death of fish and other life forms in the water. In oil drilling activities ground water supplies are often contaminated. The introduction of certain ions or compounds into water and these, in turn, reduces the water quality. When surface and groundwater are contaminated, the presence of poisonous ions is evident. However, some ions introduced into water bodies may combine with other compounds to form insoluble compounds which, when introduced into the body system cause serious harm.
There is need to increase our awareness on issues concerning water quality. In addition, industrial effluents should be handled to ensure that water sources are not polluted. Effective water quality monitoring would assist in checking how our daily activities affect the quality of our water and the impacts of the introduction of pollutants on water quality.
Across Kano State, water is used in houses for activities such as cooking, washing and gardening. Fishing is also done in some streams around the state. Domestic animals are bred in parts of the Kano State mainly, the satellite towns. These farms use water daily in feeding and washing up processes and also in irrigation. Cottage industries like bakeries, restaurants, mills, clinics and hospitals require water for their daily uses.
Although natural water is never pure, ground water sources are expected to be the purest sources of water. Never the less, underground pollution occurs from surface water sources into nearby ground water source.
The water quality parameters taken into consideration include: temperature, ph, conductivity, total dissolved solids, total suspended solids, water hardness, chemical oxygen demand (COD), biological oxygen demand (BOD), and concentration of toxic trace metals such as cadmium, lead chromium and zinc and coliform content.
Table 1.1 earth's water resources
Water Resource
Accessibility
Depth
Remarks
Water vapour
Inaccessible
Atmosphere
Gaseous
Surface water
Accessible
2"
Drinkable
Underground water
Inaccessible
100"
Drinkable
Polar ice
Inaccessible
200"
Solidified
Ocean water
Accessible
9000"
Saline
1.1 JUSTIFICATION OF THE STUDY
Although some of these pollutants are essential, others are toxic to both animals, man and plants. When these pollutants accumulate beyond the recognized and recommended limits, they become toxic to living organisms (man, animals and plants). The consumption or use of water from polluted water sources is capable of causing water or chemical related diseases. It is on this basis that an attempt is being made to determine the extent of underground pollution of water from a pond to nearby ground water sources in Kano.
1.2 AIMS AND OBJECTIVES
Aim:
To determine the extent of underground pollution from a pond to nearby ground water sources (wells and boreholes) based on certain physiochemical parameters of interest such as; total dissolved and suspended solids, temperature, conductivity, ph, toxic race metals like cadmium, lead, chromium and zinc, biological oxygen demand, chemical oxygen demand and coliform content.
Objectives:
Comparing the values obtained from analysis with that of national and international standards with a view to improve the quality of portable water.
To ascertain the pollution of ground water from surface water.
To sensitize the public on the danger and consequences of consuming or using polluted or contaminated water.
CHAPTER TWO
LITERATURE REVIEW
2.1 WATER SOURCES
Water can be obtained from various sources. They are mainly surface and ground water sources.
Surface water include rain water, lakes, rivers, shallow aquifers, streams, ponds, oceans, ice caps, glaciers etc.
Ground water include spring water, well water and borehole water.
Small amount of gases like N2, O2 and C0 in the atmosphere are contained in all natural waters.
2.2 USES OF WATER
Water is used for the following purposes:
Domestic supply (drinking, cooking, washing, batting etc).
Industrial use (as processing, cleaning and cooling water).
Agricultural use.
As a source of power.
Navigation.
Fisheries
Recreation (swimming pools, tourist sites i.e. lakes, springs etc).
2.3 WATER QUALITY
The use of water for industrial, agricultural, domestic purposes etc, causes deterioration in quality. This polluted water is harmful to the environment if not treated before its released back into use.
The main objectives of water quality control include the removal of;
Excessive colour, taste and odour.
Objectionable dissolved matter.
Aggressive constituents.
Bacterial indication of faecal pollution (Tebult, 1998).
However, different water samples contain different levels of contaminants. Therefore parameters defining water quality are diverse and these parameters vary with the corresponding water samples or use to which the waters is put.
2.4 PARAMETERS FOR DEFINING WATER QUALITY
The properties of water can be based on: Its physical, chemical and biological properties.
2.4.1 Physical Properties/Characteristics
1. Electrical Conductivity:
This is a quantitative measure of the ability of water to conduct electric current (Wilson, 1974). It can also be defined as a numerical expression of the ability of an aqueos solution to carry an electric current (LIND, 1959). Electrical conductivity is influenced by the presence of dissolved salts such as sodium chloride and potassium chloride which produce ions that migrate in solution and then generate electric currents.
Electrical conductivity is also a measure of the total dissolved solids (TDS) or salinity (LIND, 1959).
2. Turbidity:
Is a measure of the loss of transparency of a solution. The presence of colloidal solids gives water a cloudy appearance which reduces the transparency.
3. Taste and Odour:
When impurities are dissolved in water, the taste and odour become objectionable.
4. Solids (Total dissolved and suspended solids)
Total suspended solids (TSS)
These are discrete particles that can be measured by filtering a sample through appropriate filters. The magnitude of these solids depends on the type of filter (paper or sintered glass used). The pore size, the physical nature and the size of the particles (ASTM, 2004, APHA, 1985). Increase in suspended solids in water as proportional to the increase in the extent of pollution and also accounts for odour and colour (Golterman, 1978). The amount of materials deposited on the filter is the principal factor affecting separation of suspended from dissolved solids.
Total Dissolved Solid (TDS)
Total dissolved solids are due to soluble materials. This refers to the portion of today solids that passes through the filter and is expressed in Mg/L (APHA, 1985). High water with high dissolved solids is generally of inferior palatability and may induce an unfavourable physiological reaction in the transient consumer (ASTM 2004; APHA, 1985). High concentration of dissolved solids in water is also responsible for hardness, turbidity, ordour, taste, colour and alkalinity (ASTM, 2004). The maximum permissible concentration of TDS is 500 mg/L in portable water.
5. Colour:
Good water should be transparent and clear. The colour of water is expressed in Hazen units which correspond to the colouration of a series of platinum/cobalt salt dilutions.
6. Temperature:
The temperature of water is not the main issue when considering it as a physical parameter, but it's effect on other properties e.g. changing solubility of gases.
2.4.2 CHEMICAL PROPERTIES/CHARACTERISTICS
1. PH Value:
PH measures the level of acidity or alkalinity of the water sample. The PH is indicated by the concentration of hydrogen ions present (Edward, 1980). And above 7 is basic. Practically every phase of water treatment such as softening, precipitation, coagulation, disinfection and corrosion control are PH dependent (ALPHA, 1985). bonicar
Natural water have PH values in the range 4 to 9 and most are slightly basic due to the presence of bicarbonates and carbonates of alkali and alkaline earth metals (ALPHA, 1985)
2. Hardness:
Hardness of water is a phenomenon which occurs when soap does not leather easily with metals scales are produced in pipes and boilers/kettles. Hardness is caused by metallic salts (ions) of Ca and Mg and sometimes Fe (Ojuekaiye, 1998). These salts are usually in the form of bicarbonates, sulphates and chlorides (ALPHA, 1999).
3. Dissolved Oxygrn (DO)
Is the measure of the oxygen content in water. Different life forms in water need oxygen for survival water low in dissolves oxygen has an unpleasant taste while waters high in dissolved oxygen is good for drinking purpose.
4. Biological oxygen demand (BOD):
Is Oxygen used by microorganism per unit volume of water at a given time.
5. Chemical oxygen demands (COD)
Is the amount of oxygen required to decompose the organic compounds of waste water.
6. The presence of element Nitrogen and chlorine:
Nitrogen is a very important element and all biological reactions begin when it is present. Thus the concentration of nitrogen can be used to determine the quality of water samples.
The chloride content in water is another important factor for water quality analysis.
2.4.3 Biological Properties/character
One of the considerations in the quality assessments of water is the concentration of microorganisms. Therefore, bacteria can be increased or decreased in water sample depending on the purpose for which the water by coliforms leads to serious diseases.
Every water quality parameters
(physical, chemical and biological) listed above differ in different water samples. The table shows a comparison between various water sources.
TABLE.
2.5 POLLUTION
To suit environmental changes, water undergoes self purification in a biological cycle
The self- purification of water takes place in the following steps:
Sedimentation
Chemical oxidation of reducing agents.
Bacteria decay.
Biochemical oxidation; ensuring that an oxygen balance is obtained.
However, when the effects of contaminants outweigh or causes drastic change in the purification process of natural water, pollution arises.
Environmental pollution is the occurrence in the environment of any substance or condition which produces deterious effects on installations, plants, animals and man in the environment pollution occurs as a result of increased human activities.
The increased activities of man release chemical into the ecosystem which disturb their delicate balance and make the environment unfit for life. Pollutants may be biodegradable or non-biodegradable when pollutants can be broken down by microbes into simple, handless forms, they are termed biodegradable e.g. animal waste when they accumulate and cannot be broken down into simpler forms, they are termed non-biodegradable, e.g. glass, tin, etc. (Ramaligham, 1993).
Pollution occurs in different forms including industrial, agricultural, sewage related and pollution arising from natural process.
2.5.1 Industrial Pollution
The over-growing demand to produce goods for daily use has led to a continuous increase in industrial activities. Industries and factories are the main source of pollutants here. The waste produced has adverse effects on the air, land and water.
Air pollutants are classified as suspended particulate matter, gases and vapours that are present in the atmosphere in abnormally high concentrations. The main components of suspended matter are coarse particles like mineral ash or fine particles found I wood smoke coming from engine exhausts.
Incinerators, furnaces, metal industries, burning of fossil fuels in power plants, etc release various gases, smoke soot and grit which are toxic. Gaseous air pollutants are principally oxides of nitrogen, ozone, carbonmonoxide, sulphurdioxide, ammonia and other volatile organic compounds. Others are chlorofluorocarbons (CFCs), lead radon and other heavy metals.
All these gases in the air come in different proportions back to water sources by precipitations. These toxic chemicals when dissolved in water, cause serious physiological damage to humans when introduced to drinking water supplies in addition to extensive damage done to aquatic life as well.
2.5.2 Agricultural Pollution
The use of fertilizers, herbicides and pesticides by farmers have led to pollution of water and soil. Nitrogen-based fertilizers contain nitrates which are carried by surface run off and deposited into water ways and soils. These nitrates feed algae that absorb the oxygen from water and ultimately damage the animal life in oceans, streams and rivers.
Pesticides like DDT (Dichloro Diphenyl Trichloroetiane) are persistent in the environment. Their presence can cause adverse effects on a long-term basis. DDT was suspected to be a cancer causing substance, thus a potential carcinogen, and banned for agricultural use.
2.5.3 Sewage Pollution
Sewage is primarily organic in nature. Water from domestic baths, faccal matter and anything washed down drans or flushed down the toilet is contained in sewage effluent.
Sewage pollution is caused when high concentrations of untreated domestic waste enter the marine environment. Sewage is however subject to bacterial decay. Due to this bacterial activity, the oxygen concentration in the water is reduced. This can starve aquatic life of the oxygen it needs and leads to the breakdown of proteins and other nitrogenous compounds which are however toxic to aquatic organism in low concentrations.
Solids suspended in sewage may also blanket river and sea beds preventing respiration of the benthic flora and fauna (Ramaligham, 1993).
Raw sewage contains a number of strains of bacteria and viruses. Coliform bacteria is normally present in sewage because it exist in the human gut. Faecal streptococci bacteria is another indication of sewage contamination. It causes gastroenteritis.
Table B shows microorganisms associated with faecal contamination.
Table B: Some important micro bial diseases of human beings spred by faecal contamination (Ramaligham, 1993).
Microorganism
Disease
1. Viruses
a. Piconavirus
b. An RNA virus
Poliomyelitis (infant paralysis)
Hepatits A (infective hepatitis)
2. Bacteria
a. Vibrio Cholera
b. Salmonella typhi
c. Shigella dysentetial
d. Clostridium tetani
e. Salmonella sp
Cholera
Typhoid rever
Bacteria dysentery
Tetanus
Food poisoning
3. Protozoa
a..Entamoeba histolytica
Amoebic dysentry
2.5.4 Natural Pollution
This type of pollution is not as harmful as the ones listed above and occur mainly by natural means. These include contaminants arising from weathering, leaching, volcanic ash and erosion purposes. Others are animals waste in water bodies putting pressure on the oxygen level.
Tables:
2.7 Treatment Raw Water
Water treatment can be explained by the following processes.
Fultration
Coapulation/Flocculation
Sedimentation
Desludging
Disinfection
2.7.1 Filtration
Raw Water is Fine Filtered. Racks and screens are used to separate large solids. Coarse filters are used for filtration; however, they do not remove dissolved substances; only suspended solids are removed.
2.7.2 Coagulation/Flocculation
Is the addition and rapid mixing of a coagulant like alum to neutralize charges and coalesce the colloidal particles so that they agglomerate and settle. Colloidal species that are removed include clay, silica, heavy metals and organics. Flocculation is a process to promote coagulation. It is the agglomeration of the colloidal particles that have been subjected to coagulation treatments.
2.7.3 Sedimentation
Raw water is allowed to sediment in holding tanks following the principle of gravitational settling.
2.7.4 Desludging
Desludging is the removal of sludge. Sludges are impurities that have been concentrated in the form of sediments. Sludge is removed after it has drained and dried sufficiently (martin and martin 1991).
2.7.5 Disinfection
This can be achieved by dilorination. Chlorine is a strong oxidizing agent capable of reacting with many contaminants, the use of chlorine yields good results and is thus cost effective.
In chlorination, increased time of contact not only destroys microorganisms, but also gives an increased amount of chlorination by products. These by-products, these by-products are harmful and have toxic effects; hence the use of chlorine is restricted.
Ozone (O3) is used to avoid residual chloramines that result from chlorination of waste water. Ozone is a more powerful oxidant but must be produced on site because it cannot be stored.
2.8 Resulting Health Implications
The consumption of untreated or not properly treated water by humans results in the transmission of a series of diseases which can be grouped into two categories as follows:
Water related diseases
Chemical related diseases.
2.8.1 Water Related Diseases
Most diseases influenced by water are due to bacteria, viruses, protozoa and worms. When faeces and urine contaminate water, pathogenic organisms gain entrance into such water. However, the continuous use of that water source coupled with poor hygienic of the users leads to a series of disease like cholera, dysentery, etc.
Some pathogenic organisms prefer to live in an intermediate host. Ingestion of this host in polluted water leads to the manifestation of the hosted infections and diseases. Examples include the ingestion of a small crustacean Cyclops, which leads to the transmission of Dracunculiasis (guinea worm) (Bradley, 1977).
Some other infections occur by penetration of skin rather than the consumption of water e.g. schistosomiasis (Biharzia). The cercariae of schistosomiasis not only penetrates skin, it also migrates to the veins, bladder, lungs, liver or even intestine. Simulium flies transmit on chocerciasis (river blindness). Mosquitoes transmit malaria.
