The research investigated the quality of ground waters in boreholes used as potable water (drinking water and other domestic purposes) in Owerri, Imo State, Nigeria. Three boreholes were randomly selected from numerous boreholes in Owerri. Water analyses were carried out for their physicochemical parameters, major ions, nutrients and bacteriological quality. The obtained average values from the analyses are: total iron (Fe) (mg/L) = 0.03, pH = 5.9, nitrate (mg/L) = 3.0, nitrate (mg/L) = nil. The observed average values were compared with standard values of the World Health Organization (WHO) for potable water. The results showed that the groundwater qualities from the selected borehole samples are generally low in dissolved constituents and therefore it recommends that borehole waters from areas around Owerri are generally acceptable as potable water for human consumption.
Water is an essential natural resource that is vital for ecosystem functioning and human well-being. Water is an essential component of life. Globally, there is a drawback in its availability and this is increasing and duplicating itself thereby intensifying the struggle for scarce water resources as discussed by Olukanni et al. [
According to WiseGEEK [
Groundwater refers to the water that occurs below the earth surface. The main source of ground water is infiltration. The infiltrated water after meeting the soil moisture deficiency percolates deeply and becomes ground water. Groundwater is free from pollution and is very useful for domestic use in small towns and isolated farms. It can be made available at a small capital cost and also at least possible time. Ground water has been an important water resource throughout the ages. Like any other natural resource, groundwater is also not unlimited. Gbadebo & Akinhanmi [
Groundwater pollution is a growing environmental problem, especially in developing countries. The urbanization process threatens the groundwater quality because of the impact of domestic and industrial waste disposal. This results in aquifer deterioration, since some of the waste products, including sewage and cesspool may be discharged directly into the aquifer system. Water soluble wastes and other materials that are dumped, spilled or stored on the surface of the land or in sewage disposal pit can dissolve by precipitation, irrigation waters or liquid wastes and eventually seep through the soil in the unsaturated zone to pollute the groundwater as discussed by AIRBDA [
Specifically the study was carried out to determine:
The physicochemical analyses of the groundwater from the selected boreholes in the study area.
To access the quality of the groundwater from the selected boreholes as potable water in the study area.
To compare the physicochemical parameter values with World Health Organization (WHO) and Nigerian Standard for Drinking Water Quality (NSDWQ) standards for drinking water.
Imo state is one of the 36 States created in Nigeria with her capital in Owerri and is located between Latitude 5˚29'0''N and longitude 7˚2'0''E South-East Nigeria (see
has a population of about 2.5 million people. The selected boreholes are located at major and highly populated environs of Fire service, Egbu and Umuoba areas all in Owerri.
Water samples numbering seventy-five with twenty five samples from each borehole were collected from the selected boreholes in accordance with the procedure recommended in Standard Methods for the examination of water. The parameters tested are: pH, temperature, colour, total dissolved solid, conductivity, hardness, nitrate, nitrite, free chlorine, iron, copper, turbidity and sulphate. The results obtained were compared with World Health Organization (WHO) [
1) pH and Temperature
Materials: Suntex pH and temperature meter, beaker, buffer solution; 7.00 pH for alkalinity and 4.00 pH for acidity, and de-ionized water were used for the analysis.
Procedure: The pH meter was calibration with standard buffer solution of pH 4.0 and 7.0. Samples of 500 ml each were used to obtain results of pH and temperature.
2) Total Dissolved Solids (TDS) and Conductivity
Materials: TDS/Conductivity meter, de-ionized water, a beaker and TDS probe were used for the analysis.
Procedure: Samples of 50 ml each were used to obtain values of the conductivity in µs/cm and the TDS results in mg/L.
3) Turbidity, Colour and Total Suspended Solids (TSS)
Materials: The following materials were used to obtain turbidity, colour and TSS values: DR2010 data logging spectrophometer, de-ionized water and cell bottle.
Procedure: In the determination of turbidity, colour and TSS, samples of 25 ml each were used to obtain the results with the spectrophometer.
4) Iron and Copper
Materials: To obtain the values for Iron and copper, the following materials were used: Spectrophometer, Samples cell bottles, Ferrower reagent powder pillow and Cuver 1 reagent powder pillow.
Procedure: Samples of 10 ml each were used to obtain results for Iron and copper from the water samples.
5) Nitrate and Free Chlorine
Materials: To obtain the values of nitrate and free chlorine the following materials were used: Hi83200 multiparameter bench photometer, de-ionized water, Hi93728-0 reagent powder pillow for Nitrate and Hi93701-0 reagent powder pillow for Free chlorine.
Methods: Cadmium reduction method as specified by APHA [
The results of the physicochemical parameters of the selected boreholes are shown in
S/N | Parameters | Borehole water at fire service Area, Owerri | Borehole water at Umuoba, Uratta Area, Owerri | Borehole water at Egbu Area, Owerri | WHO standard [ | NSDWQ NIS.554: [ |
---|---|---|---|---|---|---|
1 | Colour (hazen unit) | 3.4 | 3.24 | 3.3 | 5.0 - 15 | 15 |
2 | Temperature (˚C) | 29 | 30 | 29.5 | 27 - 28 | Ambient |
3 | Turbidity (NTU) | 5.8 | 5.9 | 5.75 | 5 | 5.0 |
4 | Copper (mg/L) | Nil | Nil | Nil | Nil | 1 |
5 | Iron (mg/L) | 0.02 | 0.01 | 0.03 | 0.3 | 0.3 |
6 | Nitrate (mg/L) | 2.0 | 1.86 | 3.0 | 3.0 | 50 |
7 | Nitrite (mg/L) | Nil | Nil | Nil | 1.0 | 0.2 |
8 | TDS (mg/L) | 18.1 | 16.3 | 17.0 | 500 | 500 |
9 | pH | 5.9 | 5.85 | 5.7 | 6.5 - 8.5 | 6.5 - 8.5 |
10 | Hardness (mg/L) | 3.0 | 2.8 | 2.9 | 500 | 500 |
11 | Conductivity (µs/cm) | 30 | 33 | 31 | 1000 | 1000 |
12 | Free residual chlorine (mg/L) | 0.01 | 0.00 | 0.00 | 0.2 - 5.0 | 0.2 - 0.25 |
Parameter | Average values for borehole water | WHO standard [ | NSDWQ NIS.554: [ | Remark |
---|---|---|---|---|
Total iron (mg/L) | 0.02 | 0.3 | 0.3 | Pass |
Turbidity (NTU) | 5.8 | 5.0 | 5.0 | Fail |
TDS (mg/L) | 17.13 | 500 | 500 | Satisfactory |
pH | 5.82 | 6.5 - 8.5 | 6.5 - 8.5 | Pass |
Temperature (˚C) | 29.5 | 27 - 28 | Ambient | Fail |
Hardness (mg/L) | 29.0 | 500 | 500 | Pass |
Nitrate (mg/L) | 2.29 | 3.0 | 50 | Pass |
Nitrite (mg/L) | 0.00 | 1.0 | 0.2 | Pass |
Free residual chlorine (mg/L) | 0.00 | 0.2 - 0.25 | 0.2 - 0.25 | Satisfactory |
especially when other more suitable supplies are not available, as with the present Government groundwater is now the only source of potable water in Owerri. In terms of total iron, hardness and various forms of nitrogen (nitrate and nitrite) present in the water samples examined were acceptable for human consumption. However, it is important to note that free residual chlorine was satisfactory in the water samples tested.
The use of boreholes as sources of drinking water for Owerri is good in terms of quality. The pH was within standard limit required. The mean levels for free residual chlorine (Cl), nitrate and nitrite (
Based on the study the following recommendations are made:
1) There should be regular groundwater quality evaluation and monitoring and effective strategies for ensuring that WHO and NSDWQ standards are maintained for every drinking water.
2) However, indiscriminate drilling of boreholes should be checked and regulated in order to protect the public from infiltration of contaminants from soakaway pits; besides, regulators should ensure that WHO and NSDWQ standards are maintained and other government regulations are observed in order to maintain good drinking water quality.
Boniface Chidi Okoro,Regina Akudo Uzoukwu,Christopher Kparmekpo Ademe, (2016) Quality Assessment of Groundwater Sources of Potable Water in Owerri, Imo State, Nigeria. Open Access Library Journal,03,1-6. doi: 10.4236/oalib.1102445