Analysis of Borehole Water Quality of Communities
Chapter One
Objectives of the Study
Main Objective
This study was aimed at assessing borehole water quality and consumption patterns in Yei County.
Specific Objectives
The specific objectives of this study were,
- To examine seasonal variations in borehole water quality in the rural and urban areas of Yei County, South Sudan.
- To assess the effect of distance from the water source, household size, and changing seasons on borehole water consumption in the rural and urban areas of Yei County, South Sudan.
CHAPTER TWO:
LITERATURE REVIEW
GROUNDWATER
Ground water occurrence
The principal 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 vadose/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).
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