Quality assessment of borehole waters in enugu urban

Thesis Overview

<p> </p><p>INTRODUCTION<br>The use of water by man is as old as the existence<br>of human beings since water, which is a natural<br>resource, is indispensable to life.<br>Water is a common chemical substance that is<br>essential for the survival of all known forms of life. It is<br>used in vast quantities for drinking purposes, and even<br>in greater quantities for washing, bleaching, dyeing,<br>cooling, raising steam to drive engines or turbines to<br>generate electricity and in other industrial processes far<br>too numerous to mention [1,2].<br>As a result of industrialisation and urbanisation,<br>people migrate to townships and the population in these<br>cities become too high; so is the need for water. Although<br>surface water such as lakes, rivers, streams and springs<br>are easily accessible, there is a great quest for people to<br>drill borehole ground waters which are thought to be of<br>better quality[3]. It is pertinent to observe that there are<br>2<br>several human activities, which have indirect and<br>devastating effects on ground water quality. Such<br>activities include accidental or unauthorized release of<br>chemical substances, discharge of untreated effluents,<br>leaching of noxious liquids from solid waste deposits,<br>surface runoff, untreated sewage, from population<br>around the area [4,5]. This is because these pollutants or<br>contaminants are carried by water and water moves<br>easily through the soil and underlying rocks. This occurs<br>particularly where the soil is sandy, gravelley or shallow<br>or over porous limestone bedrock [6].<br>It is therefore the concern of scientists to ensure<br>that the supply of water is maintained at sufficient purity<br>for the masses to use. All the water from the borehole to<br>the consumption level ought to meet the standards laid<br>down by World Health Organization for drinking water to<br>make the water potable. Substandard water samples can<br>lead to diseases such as typhoid fever, dysentery, cholera<br>and other types of gastrointestinal disturbances[7].For<br>3<br>drinking water to be safe, the concentration of<br>undesirable substances should not exceed the levels<br>established by World Health Organization[8] as shown in<br>Table 1below<br>Table 1: WHO Permissible Values<br>Parameters WHO LIMIT Color 5 – 25 units Taste and odor Unobjectionable Turbidity 5 units pH 6.0 – 8.5 Electrical conductivity (µmhoscm–1) 50 Alkalinity (mg–1) CaCO3 100 Total solids (mg-1) 1000 Total dissolved solids (mgl–1) 1000 Total suspended solid (mgl–1) 500 Total hardness (mgl–1) CaCO3 500 Calcium hardness (mg-1) CaCO3 500 Magnesium (mg-1) CaCO3 500 Sulphate (mgl–1) 400 Nitrate (mgl–1) 50 Phosphate (mgl–1) 1.0 Chloride (mg-1) 250 Iron (mgl–1) 0.3 Manganese (mgl–1) 0.05 Lead (mgl–1) 0.05 Copper (mgl–1) 1.0 Zinc (mgl–1) 5.0 Cadmium (mgl–1) 0.05 Fecal coliform count/100ml 0 Total coliform count/100ml 0<br>4<br>This was focused on the quality of borehole waters in<br>Enugu urban in relation to World Health Organization<br>standards, to ascertain their potability.<br>1.1. BACKGROUND OF THE STUDY<br>Nigeria is located in West Africa and has variable<br>terrain. The climate ranges from equatorial in the south<br>to tropical in the centre and arid in the north. Climatic<br>variations influence the vegetations, ranging from<br>mangrove swamps in the south, tropical rainforest in the<br>centre, Savannah in the north and Sahel Savannah in<br>the north-east. The annual rainfall varies from 4000mm<br>in the south and 250mm in the north, with a national<br>average of 1180mm [9]. Geological reports gave rock<br>types as Precambrian basement in the southwest, south<br>east and north-central. The rocks include gneisses,<br>schists, migmatites, pegmatite, charnockitic and quartz<br>schist [10]. The study area Enugu urban is found in<br>Enugu State, southeast Nigeria, situated on longitude<br>5<br>70301 0E and latitude 60301 0N and has tropical<br>vegetation. The major climatic seasons are wet or rainy<br>season, which begins in March or April, and ends in<br>October and the dry season, which begins in November<br>and ends in March or April.<br>Groundwater is an important water resource in both<br>the urban and rural areas of Nigeria. Enugu which was<br>previously mined for coal produced acid wastes that were<br>rich in metal elements like Pb, Cu, Zn, As, Mn and Fe.<br>Most of these are toxic at fairly low concentrations. The<br>coal mining at Enugu especially, has the potential of<br>posing an acid mine drainage[11]. Though groundwater is<br>considered to be aesthetically acceptable for domestic<br>use, presence of poorly designed pit latrines, poor solid<br>waste management as well as poor and inadequate water<br>protection, may lead to contamination of groundwater<br>with pathogenic bacteria.<br>6<br>Also there is a growing fear of environmental<br>pollution by Lead (Pb) in the state generally due to the<br>littering of the streets with storage batteries and to a<br>lesser degree from gasoline burning engines and smokes<br>from other fuels.</p><p>Fig 1: Map of Nigeria<br>7</p><p>Fig. 1: Map of Nigeria<br>Fig. 2: Map of Enugu showing study Area</p><p>Population</p><p>Industries</p><p>Borehole</p><p>Main road</p><p>Market</p><p>Airport<br>KEY<br>8<br>1.2. SCOPE OF STUDY<br>Analysis of samples of borehole waters hand dug-wells<br>and control (distilled) water to find temperature, color,<br>pH electrical conductivity, total solids (TS), total dissolved<br>solids (TDS), total suspended solids (TSS), total hardness,<br>calcium hardness, magnesium hardness, alkalinity,<br>chloride, SO4 , NO3 , PO4 , Pb, Cu, Zn, Cd, Fe<br>contents, total coliform (TC) counts and Langelier<br>Satuation Index (LSI) using some of the parameters in<br>accordance to the standard method.</p><p>1.3. AIMS<br>– To improve man’s health, through the taking of potable<br>water<br>– To determine the extent of contamination of the waters<br>1.4 OBJECTIVES OF STUDY<br>The objectives of the study were to examine the<br>physico-chemical and bacteriological quality of water<br>from ten boreholes in Enugu urban, and to determine the<br>corrosion potential of the water.</p> <br><p></p>