Assessment of Water Quality of Some Private Boreholes in Housing Estates in Uyo Urban, Akwa Ibom State
Chapter One
Objectives of the Study
Main Objective
This study was aimed at assessing borehole water quality and consumption patterns in Uyo urban.
Specific Objectives
The specific objectives of this study were;
- To examine seasonal variations in borehole water quality in the rural and urban areas of Uyo urban, Nigeria.
- To assess the effect of distance from water source, household size and changing seasons on borehole water consumption in the rural and urban areas of Uyo urban, Nigeria.
CHAPTER TWO
LITERATURE REVIEW
CONCEPTUAL FRAMEWORK
Ground water occurrence
The principle source of borehole water / groundwater is meteoric water, that’s to say; (precipitation from rain, sleet, snow and hail), juvenile water and connate water (Gleick, 1993). Groundwater occurs in many geological formations. Nearly all rocks in the upper part of the earth’s crust possess voids or pores filled with water or air; this is the vadoze / unsaturated zone. At greater depths, all empty voids are filled with water, this is the saturated zone, and hence groundwater refers only to the saturated zone below the water table. In consolidated rocks the only voids may be the fractures or fissures. The volume of water that will drain under gravity from initially saturated rock mass to the total volume of that rock is called the specific yield of that material. All water that occurs naturally beneath the earth’s surface, including saturated and unsaturated zones is called sub-surface water (Chapman, 1996).
Host lithology
Groundwater occurs in association with geological materials containing soluble minerals; therefore its geochemistry varies with host lithology and level of aquifer (Railsback et al., 1996; Bruehl, 2011; Sanden et al., 1986; Homsby, 1999). Low land area aquifers are large but water security is compromised by limited and poor quality surface water, restricted access to the aquifer via borehole and greater demand (Calow et al., 2011). Groundwater with low values of NO3–, Cl– has zones characterized by confined aquifer conditions, while zones with higher DO, NO3– and seasonally variable Cl– are characterized by unconfined aquifer conditions (Heejun and Kang-Kun, 1997). Limey soils and rocks release calcium ions to ground water. Materials bearing Iron Sulfide release iron. Granites may release Fluoride to groundwater. Connate and fossil water may contribute to Chloride in water. Ions all increase with depth while nitrate reduces with depth (Foster and Hirata, 1988).
Groundwater flow
Water aquifers are large in extent (1-10km) yet have variations in physical and chemical properties at small scales (1-l00m). This poses a challenge in predicting transport from a potential leakage source to the receptor (Sirila et al., 2010). Transport of contaminants in soil is an important problem for different flow scales, from the fractured rocks to large underground aquifers (Hamrnon, 2011).
The rate, residence time and direction of groundwater flow, the movement of micro-organisms, pathogenic bacteria and viruses depends on the size of the pores on reactions within media, on the amount of food available and on their life span which affects its quality (Vladimir, 2003; Sanden, 1986). Deep, consolidated formations are characterized by slow groundwater movement, long residence times, ample opportunity for dissolution of minerals and therefore often poor natural water quality. These formations are confines under thick sequences of low permeability clays and are less vulnerable to anthropogenic influences (Chapman, 1996).
Groundwater quality
The quality of water is of vital concern for mankind since it is directly linked with human welfare. According to Ranjana (2010), the quality of public health depends to a greater extent the quality of groundwater. Though groundwater quality is believed to be quiet good compared to surface water, its quality is the sum of natural: geology of the environment and anthropogenic influences: withdrawal, land use change, and solid waste dumping (Chapman, 1996). Water quality parameters reflect the level of contamination in water resources and show whether water is suitable for human consumption. Contaminated water is unacceptable due to health effects, poor taste and aesthetic value to consumers (Suthra et al., 2009).
Water Parameters
Physico-Chemical and Micro-biological parameters of water indicate the safety of potable water (Macdonald and Kay, 1986) and their analysis is important for public health and pollution studies (Kot et al., 2000).
Physico- chemical Parameters
Temperature, pH, Colour, Turbidity, Total Dissolved Solids, Electrical Conductivity, Odour and Taste are the most important Physico-chemical properties of groundwater in relation to its quality.
pH is a measure of the hydrogen ion (H+) available in water. The acidity of groundwater is due to the presence of organic acids in the soil as well as those of atmospheric origin infiltrated to the water (Chapman and Kimstach, 1996). Acid rain contains dissolved Carbon dioxide (CO2),
Nitrogen dioxide (NO2) or Sulphur dioxide (SO2) often yields an elevated Hydrogen ion (H+) ion concentration and Carbonic acid (HCO) and may cause serious threat to groundwater pH (Hamil and Bell, 1986). The pH of rainwater is about 5.7 (Krauskopf and Bird, 1994). Increase in acidity is also attributed to the oxidation of reduced Sulphur compounds in the soils of the areas (Efe et al., 2005). The pH affects the solubility and toxicity of metals by influencing chemical kinetics of important constituents. Other acids such as HNO3, HNO2 and humic acid are formed as a consequence of the decomposition of organic matter and sulphuric acid is produced when minerals such as pyrite (FeS2) breakdown. High pH levels make water to become less corrosive (Gustafsson, 2003).
CHAPTER THREE:
MATERIALS AND METHODS
MATERIALS AND METHODS
Study Area
Uyo is the capital of Akwa Ibom state, a state in Nigeria.
Population Distribution across Uyo urban
Population density or population distribution across the land criterion was used to determine rural and urban areas.
Three (3) Estates: Shelter (27.6 people per square Km), Akwa ima housing (8.3 people per square Km) and Osongama estate (19 people per square Km) were chosen to represent the rural Estates. Ewet housing extention was densely populated with a vast majority living there (112.6 people per square Km), therefore it was chosen to be the urban Estate. Since Ewet housing extention was the only area that was densely populated, it was divided into 3 parts i.e. Ewet housing extention area 1, Ewet housing extention area 2 and Ewet housing extention area 3. Simple random sampling was used to select fifteen (15) boreholes from the rural and fifteen (15) from the urban. Five (5) boreholes from each of the 3 rural estates and five (5) from each of the 3 areas of the urban Estate were selected for sampling.
Determination of seasonal variations in borehole water quality
Collection and Preparation of Samples
Each borehole was flushed for 3 minutes to remove any externally induced contamination. The borehole taps were disinfected with Sodium Hypochlorite (NaOCl) and neutralized with Sodium Thiosulphate (Na2S2O3) to eliminate any contamination due to anthropogenic activity or any external natural occurrence.
Glass water bottles (250mls) were sterilized by addition of Sodium Thiosulphate (0.1ml). The boreholes were then pumped to fill the water bottles leaving an air space of 2.5cm to create space for oxygen such that organisms do not die before testing in the laboratory. The bottles were marked for identification using the labels for each borehole. The bottles were then transported to the laboratory in an insulated box to prevent external factors like high temperatures from changing some of the water parameters. Analysis commenced within 12hrs of sampling (APHA, 1998).
Physico-chemical Analyses
The Physic-Chemical parameters pH and Total Dissolved Solids (TDS in mg/L) were measured.
A multi-purpose pH meter model D46 (pH/MV/OC meter) was used to determine the pH of the borehole water. TDS meter – 4-HMD was used to determine the Total Dissolved Solids in borehole water. All the physical parameters were measured on site. Each borehole was pumped for about 3 minutes to flush out the water that had got external influence. The borehole was then pumped to fill a bucket. These parameters were all measured by dipping the respective instruments into the bucket.
CHAPTER FOUR:
RESULTS
Introduction
This chapter focuses on the results and discussions of the data collected from the seasonal borehole water quality and consumption patterns in Uyo urban. The Physico-Chemical parameters analysed included pH and TDS. The Chemical parameters included Nitrates (NO3-N), Calcium hardness as Calcium Carbonate (CaCO3) and Iron (Fe2+). The Micro-biological parameters included Total Coliform (TC) and Faecal Coliform (FC).
The results on borehole water consumption focused on the impacts of distance to the boreholes, number of house hold members and seasonality on daily per capita consumption in liters per person per day. Generic information about sex, age groups, education levels and kind of employment was also derived from the questionnaire. The results of the rural areas were compared to those in the urban to determine the impact of population density or urbanization on borehole water quality and consumption.
CHAPTER FIVE:
CONCLUSION AND RECOMMENDATIONS
Conclusion
Dry and wet seasons had impacts on all borehole water parameters determined. They all increased in the wet season except for pH that decreased in the wet season; therefore borehole water became more acidic in the wet season. Generally there was a higher degree of water pollution in the wet season even to objectionable levels in some boreholes. There was variation in all the parameters between the rural and urban areas, where Total and Faecal coliforms varied significantly. Water pH, Total coliform and Faecal coliform affected mostly urban boreholes while iron concentrations were higher in rural boreholes which could be attributed to the impact of high anthropogenic activity.
Distance from borehole, household size and changing seasons all affected amount of borehole water consumed in liters per person per capita per day. Generally the rural communities consumed less amounts of water on daily per capita basis compared to the urban communities in both seasons. Daily per capita water consumption was higher in dry season compared to the wet season due to the lack of other water sources like seasonal surface waters and rain water.
Recommendations
- Local communities, borehole management committees together with County Health Personnel should Monitor anthropogenic activities near the boreholes and carry out sanitary inspections so that hygiene and sanitation is maintained around the borehole water resources. Safe distance between the borehole and potential sources of groundwater pollution as per (Table 2.4) should be considered. Development of management and monitoring strategies for each borehole is necessary since groundwater pollution is site specific. Regular water quality assessments and treatment of polluted water be
- Nigeria Relief and Rehabilitation Commission (SSRRC) in partnership with NGO’s should conduct Water Security Mapping to help identify vulnerable areas where there is high water stress, such that these areas are given priority when it comes to allocation of boreholes.
- The Government through County water department should explore and employ Water harvesting and Conservation Techniques across Uyo urban, since borehole water which is the main source of domestic water is not evenly distributed. This is registered successful in West Mundri County, Western Equatoria, especially in Schools and
- There is need for increased number of boreholes in Uyo urban especially in rural areas where very low amounts of daily per capita water consumption were recorded. This could increase daily per capita consumption by reducing congestion, and proximity since increased access to water resources is associated with a lower risk of water borne
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