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67 Seiten, Note: A
TABLE OF CONTENTS
LIST OF TABLES
TABLE IN APPENDIX
LIST OF FIGURES IN THE
APPENDIX LIST OF FIGURES IN
THE APPENDIX ABSTRACT
1.2. Statement of the Problem
1.4. Significance of the study
2.1. Ground Water
2.2. Water Quality
2.3. Physical Parameters of Water Quality
2.3.1. Water tempera true
2.3.3. Total Dissolved Solids (TDS) and Total Suspended Solids (TSS)
2.2.4. Electrical Conductivity (EC)
3. MATERIALS AND METHODS
3.1. Descriptionofthe StudyArea
3.2. Site Selection, Data Collection and Sampling Techniques
3.3. Water Sample Analysis
3.4. Statistical Data Analysis
4. RESULTS AND DISCUSSION
5. SUMMARY AND CONCULUSSION
3.1. Demographic characteristicsof sampling area
3.2. No of covered and uncovered Wells, and mean depth and area of well water inthe study area.
4.1 The mean physical parameters of Tap Water
4.2 The pair comparison of tap Waterbetween towns
4.3 The mean physical parameters of Well Water
4.4 The pair comparison of WellWaterbetweentowns
4.5 MeancomparisonofTap WaterandWellWater
4.6 Pair comparison of tap andwellwater ofAyeletown
4.7 Pair comparison of tap and well water of Gebete town
4.8 Pair comparison of tap and well water of Watiyo town
4.9 Paircomparison of tap andwellwater ofQobotown
4.10 Pair comparison of tap and well water of Kombosha town
4.11 Pair comparison of tap and well water of Baro town
la. One-way ANOVAAnalysisof Varianceof temperature between tap water
2a. One-way ANOVAAnalysisof Varianceof pH betweenwellwater
3a. One-way ANOVA Analysis of Variance of electrical conductivity between tap water
4a. One-way ANOVAAnalysisof Varianceof turbidity betweentapwater
5a. One-way ANOVA Analysis of Variance of total dissolved solid between tap water
6a. One-way ANOVA Analysis of Variance of total suspended solid between tap water
7a. One-wayANOVAAnalysisofVarianceoftotalsolidbetween tapwater
8a. One-way ANOVAAnalysisof Varianceof temperature between wellwater
9a. One-way ANOVAAnalysisof Varianceof pH betweenwellwater
10a. One-way ANOVA Analysis of Variance of electrical conductivity between well water
11a. One-way ANOVA Analysis of Variance of turbidity between well water
12a. One-way ANOVA Analysis of Variance of total dissolved solid between well water
13a. One-way ANOVA Analysis of Variance of total suspended solid between well water
14a. One-wayANOVAAnalysisofVarianceoftotalsolidbetween wellwater
1b-42b One-way ANOVA Analysis of Variance of Physical parameters to compare tap and well water within locations 46-
1 Experimental Procedure for TDS, TSS and TS
2 PortablepH-meter (pH-013)
3 Conductivity Meter (Jenway 4320)
4 Turbidimeter (Jenway 6036)
5 Sources of Samples of Tap and Well Water
ASSESSMENT OF PHYSICAL QUALITY OF DRINKING WATER AT GUDURU DISTRICT,WESTERN ETHIOPIA.
A number of factors like geology, soil, effluents, sewage disposal and other environmental conditions in which the water stays or moves and interacts are among thefactors that affect the quality of water. The sample of water was collected from six towns of Guduru district. The objective of this study was to assess the physical quality of drinking water and suitability for drinking purpose. The physical water quality parameters examined by laboratory using standard procedure were temperature, pH, electrical conductivity (EC), turbidity, total dissolved solids (TDS), total suspended solids (TSS) and total solids (TS). ANOVA and mean comparison were made to compare the difference between physically quality of tap water sample and well water. The study show that the mean values of tap water of temperature, pH, EC, Turbidity TDS, TSS, and TS ranged from 24.41 to 27.680C, 7.35 to 7.52, 231.33 to 407.5 pS/cm,1.5 NTU to 3.13 NTU, 154.77 to 273.02 mg/l, 56.33 to 223.78 mg/l, 211.12 to 496.83 mg/l, respectively and the mean values well water of temperature, pH, EC, Turbidity TDS, TSS, and TS ranged from 24.15 to 25.01°C, 7.35 to 7.55, 59 to 761.66pS/cm,1.01 NTU to 4.26 NTU, 39.5 to 510.32 mg/l, 5.92 to 321.7 mg/l, 45.45 to 832.11 mg/l, respectively. From the result of physical parameter studied the temperature and turbidity of both tap water and well water fells the standards of drinking water which indicates not suitable for direct consumption. The electrical conductivity and total dissolved solid of Ayele well water results were above the recommended value of standards. This implies that waler from most wells in the study area is not in any w:ay safe nor suitable for direct consumption. The increasing in TDS in Ayele well water might be due to increased amounts of inorganic and organic detritus from the surrounding environment in which the well exist. The highest value of TS at Ayele well water was due to high value of TDS and TSS in the town. Further study is initiatedfor the sources of difference of physical parameters of tap and well water with in locations and along locations.
Key words: Drinking water quality, Electrical Conductivity, Total Dissolved Solids, Total Suspended Solids, and Turbidity.
Water is one of the essential necessities of life. Next to oxygen, water is the most important substance for human existence (Melese, 1998). Without it, no living thing can survive in this world. Freshwater, rivers, lakes and groundwater are used to irrigate crops, to provide drinking water, and for sanitation purpose (Economopoulos, 1993). Frequently rivers act as conduits for pollutants by collecting and carrying wastewater from catchments and ultimately, discharging it into storm water(rain water and melted snow that runoff lawns, streets and other land surfaces), which can also be rich in nutrients, organic matter and pollutants, finds its way into rivers, lakes and other water bodies.
Water quality is the measure of how good the water is in terms of supporting beneficial uses or meeting its environmental standards. Potable water is the water which is suitable for drinking and cooking purposes. Portability considers both the safety of water in terms of health, and its acceptability to the consumer, usually in terms of taste, odor, color, and other sensible qualities (Benignos, 2012).
Drinking water is defined as having acceptable quality in terms of its acceptability parameters (physical, chemical, and biological) so that it can be safely used for drinking and cooking (WHO, 2004). WHO defines drinking water to be safe as long as it does not cause any significant health risks over a lifetime of consumption, and an effort should be made to maintain drinking-water quality at the highest possible level. Pure water needed for human consumption does not always occur in nature in sufficient quality, due to the presence of dissolved or suspended impurities in most water bodies (Gold face, 1999).
Water has the ability to dissolve solids and to absorb gases and other liquids. Hence, it is often referred to as the “universal solvent”. Because of this solvent power, all natural water contains minerals and other substances in solution, which have been picked up from the air, the soil, and rocks through and over which it passes (Zeyede and Tesfaye, 2004). For as long as humans have lived near waterways, they have also used them to wash away their wastes there by polluting water bodies (Chapman, 1996).
The need for water is strongly ascending, which is not only important for domestic purpose but also vital for the development activities in both agricultural and industrial sectors. Any developmental activity is related, either directly or indirectly with water utilization (Zelalem, 2009). The quality of water is a vital concern for humankind since it is directly linked with human welfare. A water quality failure (WQF) event is often defined as an excidance of one or more water quality indicators from (parameters or classes) specific regulations.
One of the most important factors that affect drinking water quality through distribution and with sustainable use of town water supply systems is the quality of water the distribution systems deliver to the users (Brikke, 2002). If domestic water supply of any town fails to meet acceptable drinking water quality standards (that is, physical, chemical and/or bacteriological) people may stop using the scheme and resort to unsafe sources; and will be further exposed to acute and chronic illnesses (Karn and Harada, 2002). This will bring challenge in meeting the Millennium Development Goals (MDGs) of ensuring environmental sustainability, improving health and eradicating extreme poverty of the rural & town where majority of people are living in the developing world (United Nations, 2005).
Generally, the sources of water can be grouped into three namely, rain, surface (which includes river water, streams, sea water), underground and ground water (including well water and borehole water) (Oyebode, 2005). The first key step in providing safe drinking water is the selection of the best available source of water that will be the easiest and cheapest to transform into safe drinking water. Water from boreholes is a groundwater in which the depth at least 45.75m (150ft) and pumped out with the aid of a pumping machine into an overhead tank. It is generally accepted that groundwater from deep aquifers is protected from pathogen contamination by the covering soil layers (Tsen, 1999). The quality of groundwater is a function of natural processes as well as anthropogenic activities. The term groundwater is usually reserved for the subsurface water that occurs beneath the water table in soils and geologic formation that are fully saturated (Chanda, 1999). Groundwater plays a vital role in the development of arid and semi-arid zones (Arya et al, 2012). However, it is susceptible to pollution and once polluted restoration is difficult and long term measures are needed (Henry and Heinke, 2005).
Today, groundwater is the major source of water for many municipalities, industries, suburban homes and for irrigation, of farms (Bouwer, 1978). It is also the main source of water supply in Ethiopia covering about 85% (Getachew, 2004).
Ethiopia is naturally endowed with abundant water resources that can fulfill domestic requirements, irrigation and hydropower. With its current per-capita fresh water resources estimated at 1924 m3, the country is one of the sub-Saharan African countries endowed with the largest surface fresh water resource. However, only 2% of the potential is annually utilized (MoWR, 2002). The drinking water coverage in Ethiopia is less than or equal to 21% for the rural, 84% for the urban and 30% at country level. The per capita per day water consumption ranged from 3 to 201iters with median of 8.5 liters (Abera and Mohamed, 2005).
The sources of drinking water in Guduru districts towns are groundwater and tap water. The level of water quality of ground and tap water has not been scientifically tested so far to make sure that the district gets water that satisfies minimum safety standards recommended by WHO. This study is aimed to assess the level of physical quality parameters (temperature, PH, turbidity, EC, total dissolved solids, total suspended and total solids) of water samples collected from six grounds and tap water of six Guduru district towns, western Ethiopia.
The main causes of water pollution in the Ethiopian context are, Industrial activities, sewage, domestic and rural wastewater, Water quality and the risk of water-associated diseases are serious public health concerns in many developing countries like Ethiopia. This is mainly due to lack of proper research and subsequent monitoring of water quality parameters for most of the towns in Ethiopia.
The populations of Guduru district town obtain their drinking water from a river source, groundwater and tap water situated at different locations in the town. So far, there is no research conducted on the water supply system of the town that may enable one to know the quality of drinking water and the water supply network systems. The health sector of the town regularly reports that water associated diseases are one of the top-ten diseases, and there are certain indicators that the population of the town is suffering from water-associated diseases, very probably due to poor drinking water quality (GWHO, 2008). Systems that have large transmission and distribution lines may have problem on changes of pressure in the distribution system. For the reason that the increase in water age is dependent on the difference between the production and consumption times, high residence time in pipes and storage duration in water tanks some of the problems. Moreover, it is also very difficult to identify strictly the cause as well as the place of pollution.
Therefore this study tries to assess physical quality of tap and groundwater for drinking and other domestic purposes in six Guduru district towns based on physical parameters such as temperature, turbidity, pH, EC and TDS to show that significant level of physical quality the two sources and figure out which source does not meet the standards of drinking water. Furthermore, physical profile of drinking water is analyzed by researchers for the case of Guduru district.
The general objective of this study was therefore, to assess the physical quality of drinking water at Guduru district, Western Ethiopia. Hence, the study was undertaken with the following specific objectives:
> To compare the physical quality parameters (temperature, pH, turbidity, EC, TDS, TSS and TS) of drinking water source (taped and groundwater) with WHO.
Sufficient study has not been done on drinking water quality in the study area and its effect on the health of the surrounding people. But water born disease were reported different times by the Woreda health office. In addition to this the cause of these water born diseases were also not studied. Because of these, this study was initiated to assess and quantify major physical water quality parameters which have high contribution in determining water quality for drinking purpose. It is believed that the result obtained by this project makes awareness to the community and policy maker or NGO’s and implemented of the area to same extent. It can also be a base line for any interested individuals or organizations to make further study on the quality of drinking water sources, cause and effects of problems related to water quality.
Groundwater refers to all the water occupying the voids, pores and fissures within geological formations, which originated from atmospheric precipitation either directly by rainfall infiltration or indirectly from rivers, lakes or canals. Sands, gravel, sandstones, and limestone formations are the usual sources of groundwater supply though some may be drawn from impervious rocks such as granite when they have an over burden of sand or gravel.
Groundwater is a valued fresh water resource and constitutes about two-third of the fresh water reserves of the world (Chilton, 1992). The estimated groundwater reservoir of the world is about 5.0 x 1024L, this volume is more than 2,000 times the volume of waters in all the world’s rivers and more than 30 times the volume contained in all the world’s fresh water lakes (Buchanan, 1983).
Groundwater is abstracted through hand-dug wells; hand-pump operated shallow-wells and submersible pump operated deep well or boreholes (Ojo, 2002). Groundwater is often high in mineral content such as magnesium and calcium salts, iron and manganese depending on the chemical composition of the stratum through which the rock flows (Todd, 1980).Wells are divided into two namely, shallow and deep wells depending on the location of the impervious strata from which the water is obtained ( Park, 1994). Based on the mode of construction, wells can be classified into three categories namely: Hand-dug well, bored well and duplicationwell (Sangodoyin, 1987).
Wells have been dug to access groundwater for millennia. Dug wells are normally constructed manually in soft material. Generally, they are less than 20m deep and l-2m diameter although some could be 100m deep and 4m diameter and therefore have large storage capacity. An approximate yield of a properly constructed well gives between 2,500 to 7,500 m3 per day, but most domestic hand dug well yield less than 500 m3/day (Todd, 1980).
Where water depth makes it possible, people dig their own private or commercial wells and this remains the most common method of groundwater exploitation, probably even more important than drilled wells (Clark, 1998). Notwithstanding this, hand dug wells are vulnerable to contamination from activities around the top of the well. Private wells are usually safe, since they can be affected by nearby septic systems, farm animal wastes, or other source of contamination(FMDW, 1997).
Water quality is defined by certain physical, chemical, and biological characteristics (FAO, 1998). It is a critical factor affecting human health and welfare. Having good quality water is common problem in most developing countries (Ongley, 1994). The quality of water varies due to variation in both the natural geological and hydro-geological conditions and human impact. Water rock interaction plays an important role in controlling water quality. The main mineral characteristics of water, especially ground water are determined by weathering reaction-taking place close to the earth’s surface and there is a wide diversity of chemical composition related to the geology of the catchment or aquifer (Andualem, 2008).
Water has a wide range of physical characteristics that affects its quality and treatability (Hutton, 1996). Physical testing of drinking water is necessary to assure that treated water is safe and palatable to monitor the various water treatments for safe drinking water supply. Physical testing of raw water is also helpful to determine treatment techniques (Avcievala, 1991).
Measurement of the physical attribute of a stream can serve as indicators of some form of pollution. For example changes in pH may indicate the presence of certain effluents like metals, while changes in turbidity may indicate dredging in the area (Kortatsi, 2007).0ther commonly physical characteristics of a stream include temperature, color, and total dissolved solids (Svobodova el al., 1993) added that alteration of waters physical parameter includes pH, turbidity and conductivity.
In analysis of the physical quality of pipe water samples, temperature is considered as a critical parameter. It has an impact on many reactions, including the rate of disinfectant decay and by product formation (Volk et al., 2002). As the water, temperature increases the disinfectant demand and by product formation, nitrification, microbial activity, algal growth, taste and odor episodes, lead and copper solubility increases. Moreover, calcium carbonate (CaCOs) precipitation also increases (Jensen et al., 2003).It is desirable that the temperature of drinking water should not exceed 150C because the palatability of water is enhanced by its coolness (WHO, 1997). In addition to cool water tasting better than warm water, temperatures above 15 degrees Celsius can speed up the growth of nuisance organisms such as algae, which can intensify, taste, odor, and color problems
Turbidity described as a physical property of water (Tchobanoglous and Schroeder, 1987). It is a measure of the cloudiness of water and is used to indicate water quality and filtration effectiveness. Turbidity of natural water is caused by the presence of compounds such as clay, mud, organic matter, bacteria, and algae. The flow rate of river water, soil erosion, building and road construction, forest fires, logging, and mining, urban runoff, wastewater and septic system effluent, decaying plants and animals are some factors that increase the turbidity of water (WHO, 1983). Higher turbidity levels are often associated with higher levels of disease-causing microorganisms such as viruses, parasites and some bacteria (APHA, 1998). Insoluble particulate impede the passage of light through water by scattering and absorbing the rays. This interference of light passage is referred to as turbidity. The standard is a suspension of silica of specified particle size selected so that a 1.0 mg/1 suspension measures as 1.0 NTU (Vies man and Hammer, 2005).
Total Dissolved Solids (TDS) includes inorganic salts, principally calcium, magnesium, Potassium, sodium, bicarbonate, chlorides, sulfates, and small amounts of organic matter that are dissolved in water (WHO, 2004). TDS in water originate from natural sources, sewage, urban runoff, and industrial wastewater. Concentrations of TDS in water vary considerably in different geological regions owing to differences in the solubility’s of minerals and the presence of high levels of TDS in drinking water may be objectionable (WHO, 2004).Total suspended solids (TSS) include all particles suspended in water, which will not pass through a filter. Suspended solids are present in sanitary wastewater and in many types of industrial waste water. There are also nonpoint sources of suspended solids, such as soil erosion from agricultural and construction sites (WHO, 2004). Suspended particulate matters in water systems reduce clarity and contribute to a decrease in photosynthesis, act as binding sites for toxic substances and lead to increase water temperature through the absorption of sunlight (Manahan, 2000).
Electrical conductivity (EC) is a measure of how well water can conduct an electrical current (Lechevallier et al., 1990). Conductivity increases with increasing amount and mobility of ions (Lehtola et al., 2002). These ions come from the breakdown of compounds and conduct electricity because they are negatively or positively charged when dissolved in water (Lee and Kung, 2003). Therefore, electrical conductivity is an indirect measure of the presence of dissolved solids such as chloride, nitrate, sulfate, phosphate, sodium, magnesium, calcium, and iron, and can be used as an indicator of water pollution (Murphy, 2007). Electrical conductivity of water is related to total concentration of ions in the water, their valence charge and mobility. Changes in conductivity of water sample may signal changes in mineral composition of water seasonal variation in reservoirs and pollution of water from industrial wastes (AWWA, 2000).The electric conductivity, which is a measure of the ion strength in the sample does also influence lots of processes, such as the different state of metals and stability of colloids (Abdalrahim, 2007).
The total concentrations of dissolved metals and the electrical conductivity are in a close connection. The more salts (cat ions and anions) that are dissolved in the water, the higher are the values of the electric conductivity. The majority of metals, which remain in the water after a sand filter, are dissolved ions. Sodium chloride for example, is found in water as Na+ and Cl'. High purity water that in the ideal case contains only H2O without salts or minerals has a very low electrical conductivity. Water temperature affects the electric conductivity so that its value increases from 2 up to 3percent per 1 degree Celsius (Lenntech, 2006).
The pH is a measure of acidity or alkalinity of water. A pH of seven is considered to be neutral. Acidity increases as pH values decrease, and alkalinity increases as pH values increase. The pH of water affects the solubility of toxic as well as nutritive chemicals which affect the availability of these substances to aquatic organisms. As acidity increases, most metals become more water soluble and more toxic. The pH is a measure of the acid balance of a solution and is defined as the negative of the logarithm to the base 10 of the hydrogen ion concentration (WHO/UNEP, 1996).
Guduru district is found in Horro Guduru Wollega Zone which is one of the zones of Oromia Regional State with administrative center of Shambu town. The district lies between 9o16’3O” North to 9°33’0” North latitude and 37°10’0” East to 37°40’0”East longitude at 67 kilometer from Zonal administrative town (Shambu) and 268 kilometer from capital city, Addis Ababa, to the western part of the country. The study area, Guduru district, is found on an altitude betweenl450-2300meter above sea level (GWLEPO, 2013).
Horro Guduru Wollega Zone in which the study area is found has different Agro climatic zones such as kola, Wine Degas and Temperate (Degas). However, the study area experienced only Tropical and Sub- tropical Agro-climatic zones (Dawit, 2014).The area characterized by almost favorable climate with better rainy seasons with only five to six months are dry in the year. Hence, the study area receives about 1450-2500mm rain annually and with the maximum and minimum temperature of 220c and 190c, respectively (GWLEPO, 2013). The topography of the study area is almost flat with four kinds of soil types namely, Sandy (14%), Clay loam (5%), Clay (1%) and Cilty-loam dominating the area (Dawit, 2014).
This district is the largest in Horro Guduru Wollega zone with 6 small towns and 31 farmers association kebele and a total population of 131145(CSA, 2007). Its area coverage was about 140869.069 hectare orl406.89 km2 (GWLEPO, 2013). The study was carried out in six towns of the Guduru district namely (Ayele town, Gebete town, Watiyo town, Qobo town, Kombolcha town and Baro town).
Abbildung in dieser Leseprobe nicht enthalten
The demographic characteristics of sampling area and well water used taken from Woreda water resources office were putted in the following table.
Table 3.1 Demographic characteristics of sampling area
Abbildung in dieser Leseprobe nicht enthalten
Source: Guduru Woreda town’s administrations (2009)
Table 3.2 No of covered and uncovered Wells, and mean depth and area of well water in the study area.
Abbildung in dieser Leseprobe nicht enthalten
Source: Guduru Woreda water resources office (2008)
Sampling were collected from 18 shallow well (uncovered) and 18 tap water once a week for a period of three weeks from six sampling towns with three replication from tap water and well water. The Water samples from all the towns (Ayele town, Gebete town, Watiyo town, Kobo town, Kombolcha town and Baro town) were collected using 0.5L plastic bottles for different physical water quality test. Before sample collection the bottles were washed with nitric acid and then rinsed with distilled water to avoid contamination and unpredictable changes in characteristic as per standard procedure (APHA, 1998).
Samples from wells were obtained by direct immersion of sample containers into the reservoir handled by rope. Tap water samples were taken directly from the faucet. After the collection the samples, they were transported to Fincha Sugar factory’s soil and water laboratory by using cool box. Water temperature and pH were measured at each water sampling site prior to sample collection and total solids(mg/l), total dissolved solids (mg/1), total suspended solids (mg/1), Electrical conductivity (ps/cm) and Turbidity (NTU) which were analyzed in laboratory within 24hours after collection. The analysis was done based on the standard of UNESCO/WHO/UNEP (1996 and APHA (1998).
The collected water samples were analyzed for quality physical parameters such as temperature, total solids, dissolved solids, suspended solids, turbidity, pH and electrical conductivity.
The temperature and pH was measured using thermometer, portable digital pH meter (pH013) respectively immediately on site prior to sample collection. Turbidity was determined using a standardized turbid meter (JENWAY 6035). The samples were poured into the sample vial and the bottle was then inserted into the turbid meter until the reading was obtained and recorded using the procedure of Van Reeuwijk, (1992).
Electrical conductivity (ECW): was determined by using a well calibrated electrical conductivity meter (Jenway conductivity meter 4320 model). The probe was dipped into the bottle of the samples until a stable reading was obtained and recorded according to Greenberg etal. (1992).
Total dissolved solids (TDS) Gravimetric method: A portion of stirred water was filtered out with filter paper of thickness 185mm with paper type no 5 and filtered through a 2pm filtration paper and 50mL of the filtrate poured into a pre-weighed evaporating dish. Through the procedure for determination of total dissolved solid, the total dissolved solid was indicated by weighting the solid residue obtained by evaporation of a measured volume of water samples according to Karnwar et al., (1980).
Abbildung in dieser Leseprobe nicht enthalten
Where B = weight of dish +dried residue (mg) and A= initial weight of dish (mg)
Total suspended solid(TSS):100ml of water samples and pre-weighed filter paper of thickness 185mm with paper type of watman no 5 and 2pm pore size filtration paper. The pre-weighed filter papers were wetted in the distilled water sample and 100ml of water samples were filtered. Then the filter paper is transferred to evaporating dish and dried in an oven at 1050C for lhr until the liquid completely evaporated. The filter paper was then removed from the oven and allowed to cool in desiccators and weighed for the difference of weight. The increment in the weight of filter represented the TSS (APHA. 1975). Finally, the suspended solid was calculated from the weight difference of the filter paper.
Abbildung in dieser Leseprobe nicht enthalten
Where B=weight of filter paper +dried residue (mg) A= initial weight of filter paper (mg)
A total solid (TS): Total solids simply determined from the sum of total dissolved solid and total suspended solids. Total solid =Total dissolved solid + total suspended solid.
Data were recorded, organized and summarized using Microsoft excel window 7 and analyzed by SAS Version 9.1.3 using one way ANOVA with completely randomized design (CRD). The differences among means of the physical parameters were computed by using mean and least significance differences (LSDs) at (P<0.05). Least significance differences (LSDs) at 5% level of probability was used to compare variations in water quality under different sources for both tap and well water.
The tap and well water samples collected from six locations were analyzed for various physical parameters (temperature, pH, and turbidity, EC, TDS, TSS, and TS) and compared within locations and along a location between water sources (tap and well). The results of thesis analysis were presented in (Tables 4.1 - 4.11) below. ANOVA tables for all parameters were shown in Appendix (Table la-14a and lb -42b).
Table.4.1 The mean of physical parameters of tap water
Abbildung in dieser Leseprobe nicht enthalten
PCD (pair comparison difference) values in the same column with different superscripts are significantly different and the same superscript shows similarity.
Temperatures of tap water samples were ranges from 24.410C to 27.68°C with a minimum value of 24.410C for Kombolcha town and maximum 27.68°C value for Baro town as shown in (Table 4.1). There were no significant differences in temperature between Ayele and Gebete towns, and between Watiyo, Qobo, Kombolcha and Baro. But there were a significant difference between Ayele and other towns except that of Gebete and Watiyo. Similarly between Gebete and Watiyo, Qobo, Kombolcha and Baro towns, there were significant differences (Table 4.1). These implies that tap water temperature were affected by location as shown in Appendix (Table la).Tap water temperature values obtained for all towns were above the recommended <150C value given by WHO (1997) . However, for these towns it was above the recommended value by about 66%. A high temperature causes thermal pollution and adversely affects aquatic life and cause faster settling of solid particles which may affects the health of the user. A similar study conducted in Debrezeit town, showed slightly lower mean temperature of 23.20C from different water source samples (Desta, 2009).
The pH result indicated that the mean value ranges from 7.35to 7.52 with the minimum value obtained from Qobo town and the maximum value from Ayele town as shown in (Table 4.1). In this table, it is possible to deduce the mean difference for all pH value is within the recommended limit of value 6.5-8.5 as recommended by WHO (2004).There were no significant difference in pH among all the taps water (Appendix Table 2a). A similar study conducted by Getahun et al, (2013) in Horro Guduru Wollega Zone of Abay Chomen district, shows that water pH ranging from 6.52 to 7.32 with mean value of 6.68. This result is comparable to the results obtained in this study.
The mean electrical conductivity of tap water samples ranges from 231.33pS/cm to 407.5pS/cm with minimum value was obtained from Ayele town and the maximum value from Gebete town (Table 4.1). There was significant difference in electrical conductivity among tap water Appendix (Table 3a). The result obtained was slightly deviated from the recommended 250-750 pS/cm standards of WHO for drinking water WHO (1993).The average mean value of electrical conductivity of tap water lowered by 180.58pS/cm (24.07%) as compared to WHO standards. A similar study conducted in Horro Guduru Wollega Zone of Fincha valley, by Getahun et al, (2013) found lower than value at Guduru district which is 100-730 pS/cm and the reasons given for high level of Ec value at this study area may be due discharge of untreated wastewater, infiltration and agricultural runoff.
The resulted measurement indicates that the samples of tap water have a turbidity range of 1.5NTU to 3.13NTU with the minimum value at Watiyo town and maximum at Gebete town (Table 4.1). According to WHO (2012), this value of turbidity is larger than 1 NTU which is not recommended for drinking. Higher level of turbidity affects the performance of water quality and increases the temperature of water. The high turbidity may be caused due to soil erosion urban area and agricultural lands, waste etc. There was a significant difference in turbidity between tap water Appendix (Table 4a) which implies that turbidity of tap water was highly affected by location.
From the study total dissolved solid (TDS) of tap water was found to be 154.77mg/L to 273.02 mg/L where the minimum and the maximum values obtained at Ayele town and Gebete town respectively (Table 4.1). There were significant differences in tap water among locations as shown Appendix (Table 5a). The value obtained were within the range of the recommended 500 mg/L value given by WHO (2008) . These values were much greater than TDS value recorded in Gimbi town reported by Gurmessa, (2015) which ranges from 42.6 mg/L to 51.6 mg/L.
The total suspended solids of the water samples were ranges from 56.33mg/L to 223.78 mg/L where the minimum value obtained at Ayele town and the maximum obtained at Gebete town (Table 4.1). There was a significant difference in TSS between locations Appendix (Table 6a). This means TSS was affected by location as shown Appendix (Table 6a). The values obtained for total suspended solids were below the EU recommended 500mg/L limit (EPA, 2001).
The mean values of total solid ranges from 211.12 mg/L to 496.83 mg/L were the minimum mean value was obtained from Ayele town while the maximum from Gebete town(Table 4.1). There was a significant difference in total solid between locations as shown in (Appendix (Table 7a).This shows that the total solid of tap water affected by location.