Physicochemical and Heavy Metal Assessment of Water From Selected Boreholes in Kaura-namoda Local Government Area, Zamfara State, Nigeria
Chapter One
Aim and Objectives of the Study
This study aimed to assess the quality of borehole water sourced from selected boreholes in Kaura Namoda Local Government Area. To achieve this aim, the objectives were as follows:
- To determine the level of heavy metals in borehole water which include: zinc(Zn), copper (Cu), iron (Fe), cadmium (Cd), lead (Pb) and manganese (Mn).
- To determine the physicochemical properties of the underground water (borehole) which include: temperature, turbidity, total dissolved solid, electrical conductivity, pH, phosphates, sulphates, nitrates, total hardness, chlorides and
- To compare the level of heavy metal and physicochemical parameters obtained from the analysis with the WHO, NSDW and USEPA standards for drinking water to ascertain the suitability of the water for drinking purposes.
CHAPTER TWO
LITERATURE REVIEW
Alexander (2008) investigated the groundwater quality of Mubi town in Adamawa State, Nigeria. Ten groundwater samples from boreholes and dug wells were randomly collected during the raining seasons in the months of June, July and August 2007. The results obtained on analysis showed fluoride as the only physicochemical parameter that was not within the desirable limit for drinking water. From the study, it was concluded that the boreholes and dug well water in Mubi North Local Government Area of Adamawa State were generally suitable for drinking and domestic purposes. The researchers however recommended the need for routine checks of the water quality of the area investigated.
Nkansah and Ephraim (2009) carried out physicochemical analysis of water from selected boreholes in the Bosomtwima-Kanwoma district of Ghana within the month of June, 2008. The results obtained showed variation of the investigated parameters in samples as follow: pH 5.1-6.8, electrical conductivity (EC) 101-111 µS/cm, turbidity 02-45.0 NTU, colour 5- 60, total hardness 3-394mg/l, chloride 9-60mg/l, sulphate 0.5-17mg/l, phosphate 0.1- 2.4mg/l, iron 0.1-3.4mg/l, manganese 0.0-0.8mg/l, copper 0.01-0.3mg/l, zinc 0.0-3.3mg/l, cadmium 0.00-0.003mg/l, lead 0.00-0.038mg/l and sodium 6-87mg/l. The study concluded that the water from the region was harmless for house consumption even though there were isolated cases of high level of turbidity and trace metals when compared to the WHO standard for drinking water.
Iyasele and Idiato, (2012) in a study conducted to evaluate the groundwater quality in Edo North of Edo State, Nigeria. Thirty samples of water were collected from thirty boreholes in different locations and the analysis showed that pH, magnesium and iron on the average had values above the recommended WHO standards for drinking water. While other parameters like the turbidity, ammonium, total hardness, electrical conductivity, total dissolved solid, zinc, lead, cadmium and chloride level were all within the limits as recommended by WHO (2006). It was concluded in the work that the water from the study area needs mild treatment to meet the WHO standard limit for potable water.
Ilechukwu and Okonkwo (2012) carried out an investigation on the heavy metal levels and the physicochemical parameters of borehole water in Nnewi, Anambra State of Nigeria. In the investigation, ten water samples from six randomly selected boreholes were analyzed. The results of the physicochemical analysis were obtained in the following range pH (6.38- 8.42), temperature (23-26oC), electrical conductivity (30.22-222.2µS/cm), sodium (0.46 23.0mg/l), potassium (0.07-2.49mg/l), chloride (15.57-36.03mg/l), and hardness (45- 275mg/l). The concentrations of heavy metal in the samples were found within the following range; lead (0.02-0.08mg/l), iron (0.02-0.08mg/l), copper (0.03-0.07mg/l), and zinc (ND-0.07). Cadmium was below detectable limit in all of the samples. Apart from lead that was found to be higher than the recommended limit for drinking water by WHO, 2006, all other results obtained were within the recommended limits. The study recommended that potable water sources in the study area should be routinely monitored to ascertain its suitability for drinking purposes.
In another research conducted to evaluate the groundwater quality in villages surrounding Chuka town, Kenya by Ombaka et al., (2013) the results showed that pH, turbidity, fluoride, iron, manganese and lead were all above the recommended level by WHO, 2006 while other parameters investigated were within the required levels of WHO. The study concluded that people using these water resources were at a potential health risk.
Tiimub et al., (2012) investigated the quality of groundwater for drinking at Nkawkaw in eastern region of Ghana. The results obtained included: conductivity (819-1052µS/cm), turbidity (0.59-23.5NTU), manganese (0.038-0.638mg/l), aluminum (0.064-0.47mg/l), total hardness (47.0-56.7mg/l), sulphates (11-15mg/l), fluoride (0.16-1.28mg/l), copper (0.11-0.18mg/l), zinc (0.03 to 0.14mg/l) while arsenic was not detected. The findings concluded that the users of groundwater resources at Nkawkaw were not likely to develop immediate adverse problems as far as the results were concerned but possible defects due to the consumption of water with high levels of conductivity, turbidity, manganese and aluminum which exceeded the WHO, 2006 permissible limit might be encountered if accumulated beyond the tolerable concentrations in the body.
Also, the heavy metal status of boreholes in Calaber South Local Government Area of Cross River, Nigeria has been studied by Njar et al., (2012). Four functional boreholes in the area were sampled in the month of September, 2009. The results obtained showed that the concentrations of iron, zinc and manganese were within WHO maximum permissible limit with mean values of 0.065mg/l, 0.015mg/l and 0.002mg/l respectively. The level of copper, chromium and lead in the sampled boreholes was zero, indicating the absence of detectable limit of these metals in the sampled boreholes. The study recommended that in order to maintain quality status of the boreholes in the area under study, routine monitoring and assessment of borehole should be adopted.
CHAPTER THREE
MATERIALS AND RESEARCH METHOD
Preamble
In the preparation of reagents, chemicals of analytical grade and distilled water were used. All glassware were washed with detergents and rinsed properly with distilled water before use.
Description of the Study Area
Kaura – Namoda local Government Area in Zamfara State of Nigeria is located between latitude 120 16’43.56’’ to 120 41´4.48N and longitude 60 25’ 34.87” to 60 51’53.92E. It is bounded in the north by Zurmi Local Government Area, in the south by Bungudu Local Government Area, in the east by Birnin Magagi Local Government Area and in the west by the Maradum Local Government Area (Figure 3.1and 3.2) and has it’s headquarter located in the town of Kaura-Namoda. It has an area of 868km2 and a population of 281,367 at the 2006 NPC census. The inhabitants of the area are predominantly farmers that engage in commercial crops and animal production. The major source of their water in recent time is the groundwater in the form of boreholes which are being drilled across the entire study area mostly as government projects and in some cases by individuals.
CHAPTER FOUR
RESULTS
Determination of Physicochemical Parameters
The results for physicochemical determinations are presented in Table 4.1 and the comparison of results with the standards for drinking water in Figures 4.1-4.4. The results of physicochemical parameters as presented in Table 4.1 were described below:
Temperature
The values of temperature obtained ranged from 28.50±0.06 to 29.60±0.15ºC (Table 4.1). The minimum value of 28.50ºC and the maximum value of 29.60ºC were obtained from the boreholes designated as BW8 and BW16 respectively.
CHAPTER FIVE
DISCUSSION
Physicochemical Parameters
Temperature
The relatively low sampling temperature recorded could be attributed to the time of collection of the samples which was in the morning. The temperature of drinking water is often not a major concern to consumers especially in terms of the quality. The quality of water with respect to temperature is usually left to the individual taste and preference and there are no set guidelines for drinking water temperature. Nkansah and Ephraim, 2009 reported low temperature in the physicochemical analysis of water in Ghana which they attributed to the time of sampling.
pH
The pH values of all the sampled borehole water tested were within the WHO 2006, NSDW 2007 and USEPA 2012 acceptable range of 6.5 to 8.5 except for the BW17 with the pH of value of 6.40±0.10. Although the values indicated that most of the water samples were slightly acidic and few slightly basic, the consumers of the water are not at any health risk due to pH. Ilechukwu and okonkwo, 2012, reported pH of range of 6.38 to 8.42 and concluded that the consumers of such water in that pH range are not at any health risk due to pH.
CHAPTER SIX
SUMMARYOF FINDINGS, CONCLUSION AND RECOMMENDATIONS
Summary of the Findings
The results obtained from the twenty boreholes investigated showed that the physicochemical parameters which include turbidity, TDS, electrical conductivity, pH, phosphate, fluoride, manganese and nitrate had values that were within the WHO (2006), NSDW (2007) and USEPA (2012) permissible limits for drinking water. However, parameters which include chloride was detected at the level within the acceptable limit of 250mg/l except in two boreholes BW6 (487.01mg/l) and (BW12 474.61mg/l) while hardness had all values still within the recommended limit of 500mg/l for hardness in drinking water by WHO 2006 and USEPA 2012 except in three boreholes BW3 (801.5mg/l), BW4 (663.2mg/l) and BW6 (690.2mg/l) that recorded above the recommended limit. Sulphate was found to have values above the permissible limit of 250mg/l as recommended by WHO 2006 and USEPA 2012 in all boreholes investigated except in three boreholes BW1 (236.7mg/l), BW2 (225.5mg/l) and BW3 (210.0mg/l).
Also, the results obtained showed that the heavy metals which include zinc were detected at level within the acceptable limits of 3.0mg/l by WHO 2006 and NSDW 2007 for drinking water in all the boreholes except for one borehole (BW6) that record 3.5mg/l for zinc. Cadmium had values that were within the acceptable limits of 0.003mg/l in all the boreholes except in six boreholes which included BW6, BW8, BW15, BW17, BW18, BW19 and BW20 in the range 0.004-0.007mg/l while iron also had values within the acceptable limit of 0.3mg/l in all the boreholes except five boreholes which included BW6, BW8, BW12, BW16, BW17 at concentration range of 0.592-1.856mg/l. Copper was below detectable limit in all the boreholes except in one borehole (BW3) where it was detected in the concentration of 0.091mg/l which is still within the acceptable limit of 2mg/l by the WHO regulatory body while lead had values above the acceptable limits of 0.05mg/l by the WHO regulatory body in the following nine boreholes BW3, BW9, BW11, BW15, BW16, BW17, BW18, BW19 and BW20 at the concentration range of 0.013-0.023mg/l.
Correlation of the parameters investigated suggested agricultural activities and the nature of the rocks underlying the study area as the possible sources of contamination of the underground water (borehole water) studied.
Conclusion
Based on the findings, it is evident that not all the boreholes investigated had parameters that were in conformity with the WHO 2006, NSDW 2007 and USEPA 2012 recommended permissible limits for drinking water. Therefore, possible adverse effect due to consumption of the water containing high levels of these parameters may occur among the inhabitants of this study area especially in the cases of lead and cadmium if they bio- accumulates beyond the tolerable concentrations in the body.
Recommendation
Based on the outcome of the study, the following recommendations are made: Sampled boreholes in the study area that their parameters measured were not in conformity with standards for drinking water (especially in the cases of lead and cadmium) should undergo treatment before consumption.
Relevant authorities should ensure that the inhabitants of the study area are educated on the needs not to sight boreholes close to farm lands so as to avoid contamination resulting from farming activities.
Water quality assessment should be carried out on the boreholes in the study area at least once every three years. This will ensure that incidence of contaminations are noticed earlier for remedial actions to be taken.
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