Groundwater Quality Assessment in a University Sub-Urban Community in Delta State , Nigeria : Part A-Physicochemical Analysis

This study provides detailed scientific information on the physicochemical properties of drinking water from groundwater in a Nigerian university sub-urban community. Water samples from boreholes (BHs) and handdrawn wells (HDWs) in the community were collected and analyzed for their biological and physicochemical parameters, and the metals from July 2016 to January 2017 for wet and dry seasons. Results obtained, showed that the physicochemical factors complied with the World Health Organization (WHO) guidelines, except for pH being lower in some locations. In the wet and dry seasons, pH varied from 4.4 to 6.2 and from 4.8 to 6.7 respectively. While the mean value for wet season was 5.7, dry season was 5.9; to give a seasonal mean difference of 0.2.Cd and Pb, in both wells, for many locations, were slightly higher than the prescribed limits. The slight elevated concentrations of Pb and Cd could be attributed to oil exploration activities in the study area. The study recommends the provision of improved drinking water in the community. DOI: https://dx.doi.org/10.4314/jasem.v23i1.22 Copyright: Copyright © 2019 Owamah. This is an open access article distributed under the Creative Commons Attribution License (CCL), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Dates: Received: 31 December 2018; Revised: 18 January 2019; Accepted 26 January 2019

The need to regularly monitoring of the quality of groundwater used as drinking water in rural and suburban communities of developing countries cannot be over-emphasized (Owamah et al., 2013;Sojobi, 2016).This is because, inadequate access to potable water and unavailability of reliable information on quality are major contributors to frequent outbreak of pathogenic diseases in the region.Oleh is one of such communities in Nigeria but peculiar in this circumstance as it houses one of the major campuses of the Delta State University, Abraka.The provision of water in Nigeria is constitutionally, the sole function of government.However, the inability of government to meet with the daily demands of water for the people has forced millions of Nigerians to seek alternatives such as drilling of their own boreholes and hand-drawn wells.Inadequate hygiene, poor sanitation and unsafe drinking water cause over one million global annual deaths and about eighty percent of all ailments in developing nations (WHO, 2012).Furthermore, about 50% of the global number of persons without access to clean water live in sub-Saharan Africa.At the moment, those who live in the area of study, basically, depend on water from boreholes and hand-drawn wells (groundwater) since there is no pipe-borne water supply.A lot of water wells were installed without adherence to the standards of the supervising ministry thereby leading to compromised water quality.This study was therefore carried out to evaluate the physicochemical parameters of groundwater in a university sub-urban community in Delta State, Nigeria.

MATERIALS AND METHODS
Study area description: Oleh is the administrative head of the Isoko South Local Government Area (ISLGA), Delta State.The 2016 census of Nigeria put the population of ISLGA at 323,800 and indicates that ISLGA is one of the most populated LGAs in Delta State (NPC, 2018).Oleh community is the most populated of all the communities in the ISLGA.The coordinates of ISLGA is 5.43° N, 6.20° E (Fig. 1).ISLGA resides within the tropical rainforest belt and does experience tropical wet and dry climate.
The main economic activities are food crop farming, animal hunting, trading, and artisan and civil service jobs.Oleh has several primary, secondary and a tertiary schools (Faculties of Law, and Engineering of the Delta State University) with Christianity as the predominant religion.
Water Sampling: Sampling of the borehole and handdrawn well waters were carried out using one and half Groundwater Quality Assessment in a University…..

OWAMAH, HI
(1.5L) capacity high-density PET screw-capped containers from June 01, 2016 to January 31, 2017.Before collection of the actual sample, bottles were washed for three times and thereafter stoppered, labeled, ice-cooled and transported to Jacio Environmental Limited, Effurun, Delta State, Nigeria.

Fig. 1: Map of area of study
Following the work of Owamah et al. (2013), at each sampling point, acidified and non-acidified samples were collected.Autoclave-sterilized bottles were utilized for the collection of samples for bacterial analysis.Eighteen (18) raw water samples, three (3) from each district, were collected every month to amount to a total of eight (108) samples.

Analytical procedures:
The parameters; total dissolved solids (VSI 22, India), temperature (HI 98517) , pH (HI 9024-C), electrical conductivity (HI 2315) and salinity (HI 19311) were determined on site using the portable meters.Dissolved oxygen was determined using the prescribed methods in APHA (2012).Through the use of a UV spectrophotometer (DR 2800, HACH, Washington, USA) and adopting ultraviolet spectrophotometer screening method, the anions were determined in accordance with the methods prescribed in APHA (2012).The enumeration of the total coliform bacteria was done according to the guidelines in the analyses of metals was done using atomic absorption spectrophotometer (Sens AA 3000) and in accordance with the methods in APHA (2012).
Statistical analyses: Analyses of data obtained were done using Microsoft Office Excel 2010 software and the Analysis of Variance (ANOVA) statistical tool at P < 0.005.The mean and standard deviation of the parameters analyzed were computed for both seasons.
Seasonal variations were then computed as the difference between the wet and the dry season mean values taking the wet season as the reference point.

RESULTS AND DISCUSSION
Physicochemical parameters: Table 1 and Figs . (2a -2e) show the values of some of the physicochemical parameters obtained in this study.From this study, pH was found to range from 4.90 to 6.20 in hand-drawn wells and 4.40 to 6.70 in borehole water samples (Table 1).In the wet and dry seasons, pH varied from 4.4 to 6.2 and from 4.8 to 6.7 respectively.While the mean value for wet season was 5.7, dry season was 5.9; to give a seasonal mean difference of 0.2.This indicates that the pH of groundwater sources in the community was fairly constant, season notwithstanding.Granted this, pH values in the wet season were however, generally, higher than dry season values.This could be associated with the rise of water level during wet seasons, which brings with it some level of dilution.The most acidic values were got from YM district borehole and Old OER district hand-drawn well water samples.For both wet and dry seasons, borehole water samples were found to be more acidic than the hand-dug well water samples.
A maximum pH of 6.7 was obtained from a borehole in GRA district in the month of September (Table 1, Fig. 2b).The pH values obtained in this study are similar to reported values for groundwater sources in neighboring Isoko North communities (Owamah et al., 2013).Since the WHO prescription for pH lies between 6.5 and 8.5, groundwater sources in the community, may need to be treated with lime to raise it to the desired level.Though pH is not a major health related water quality parameter, low levels of it affect the state of other water quality parameters like solubility of metals and pathogen survival and hence could be capable of causing indirect health problems to humans (Khan et al. 2013).
Drinking water with low pH could also cause gastrointestinal irritations.
The lower than permissible pH range obtained from the different water sources can be linked to the geological formation in the community (Sojobi, 2016).Similar findings of low pH values were obtained for groundwater sources of neighboring Isoko North Local Governmental Area communities by Owamah et al. (2013).There was no significant difference (p > 0.05) in pH among the sampling sites, wells and across the seasons.The highest EC was obtained from a hand-drawn well (HDW) within FL district (486 μS cm -1 ) in the month of October.This was closely followed by another HDW at OER district (450 μS cm -1 ) (Table 1).The values are in accordance with the stipulated limit of 1000 μS cm -1 by the SON (2007) and the WHO (2006) , 2016).Mean TDS values obtained for wet and dry seasons are 54 and 52 mg L -1 respectively, with a seasonal mean variation of -2 mg L -1 (wet-dry).It ranged from 10 to 134 mg L -1 in the wet season and 12 to 134 mg L -1 in the dry season.
Hand-drawn well water samples from OER district had the maximum dry and wet season TDS of 134 and 130 mg L -1 , respectively (Fig. 2e).Compared with borehole water samples ( The seasonal average values for DO are 9 and 8 mg L - 1 for wet and dry seasons respectively.It ranged from 10 to 13 mg L _1 for wet season and 10 to 12 mg L -1 for the dry season.Fig. 2c shows the values of DO obtained from boreholes and hand-drawn wells in both seasons.The DO values obtained in the study area are above the WHO (2006) desired value of 4 mg L -1 and hence in order.BOD ranged from 5-7 and 4-8 mg L -1 for wet and dry seasons, respectively (Fig. 2d).
For both seasons, the seasonal mean value is 6 mg L -1 (Table 1).Ademoroti (1996) and Owamah et al. (2013) reported that the maximum allowable BOD5 is 6 mg L -1 ; as higher values mean organic contamination.
Anions:  While the minimum Cl -concentration of 2±0.5 mg L -1 was obtained from a bore-hole in IT district, during the dry season, the maximum of 65±1.6 mg L -1 was from a hand-drawn well in GRA district in the wet season.The small values of the standard deviation imply minor variability in the concentration of Cl -. .The values of Cl -concentration obtained are below the stipulated maximum permissible limit of 250 mg L -1 by the SON (2007).This indicates that chloride is of no health concern in groundwater of the study area.A previous study by Dahunsi et al. (2014) on some major cities in Ogun and Lagos States, Nigeria also reported low concentration of chloride of the range of 1.97-9.04mg L -1 for boreholes and wells showing that chloride may not be a major source of worry for groundwater used as drinking water in Nigeria.For wet and dry seasons, the mean concentrations of NO3 - obtained were 1 and 3 mg L -1 respectively, and are similar to values obtained for neighboring Ndokwa East, and Isoko North Local Government Areas of Delta State by Egboh and Emeshili (2008) and Owamah et al. (2013), respectively.NO3 -concentrations were significantly higher (p < 0.005) in the water samples of the hand drawn-wells than boreholes'.It also varied across the districts for the hand-drawn wells and boreholes.Though nitrate was not detected in the water samples of one handdrawn well and two boreholes from three different districts (Table 2), its concentration of (1-3 mg L -1 ) in the rest other water samples is below the stipulated level of 50 mg L -1 set by SON (2007).There was no significant (p < 0.05) variation of nitrate concentration among all the sampling locations and among the wells.For wet and dry seasons, the concentration of SO4 2-obtained ranged from 2 to 28 mg L -1 with seasonal mean values of 10 and 7 mg L -1 for wet and dry seasons respectively.The observed seasonal mean variation is 3 mg L -1 .Much higher values were obtained during the wet season and from hand-dug wells.Though sulfate is one of the least toxic anions, ingestion of excess sulfate could cause dehydration and laxative action (Dahunsi et al., 2014).Sulfate values in this study area are below the WHO (2006) and SON (2007) stipulated guidelines of 500 mg L -1 and 100 mg L -1 respectively (Table 5).

Metals:
The mean concentrations of metals (Na, K, Mg and Ca, Pb, Cd, Zn, Cu, Fe and Ba) detected in this study are shown in Table 3. Na concentration range of 2,200±110 to 72,100±13340 µg L -1 from this present study, is below the prescribed limit of 200,000 µg L -1 set by the WHO (2006) and SON (2007) (Table 5) and hence not considered a contaminant.Colour apparent (Hz) 15 -apparent (Hz) 15 (TCU) Notes: Apart from pH and parameters with indicated units, the unit of parameters is mg/L *World Health Organization; Standard Organization of Nigeria.Sources: Adapted from Dahunsi et al. (2014) and Sojobi (2016) following minor adjustments Apart from water samples of HDW in YM district with Fe concentration of 850±290 µg L -1 , above the 300 µg L -1 of SON (2007), the rest other values of Fe obtained across the districts (Table 3) were below the specified maximum permissible level.High levels of Fe in water could lead to characteristic reddish staining and increased turbidity (Mkwate et al., 2017).The value of potassium obtained, is in line with the claim of Mkwate et al. (2017) that potassium concentration in natural waters has been widely reported to be low (0-15,000 µg L -1 ).Potassium levels obtained in this study are below the recommended limits of 25,000-50,000 µg L -1 (Sojobi, 2016) for drinking water.From Table 3, the seasonal mean concentrations of Na, K , Mg, and Ca are 17,700 µg L -1 -15,300 µg L -1 , 12,100 µg L -1 -9,000 µg L -1 , 11,000 µg L -1 -4,000 µg L -1 and 10,000 µg L -1 -8,000 µg L -1 (wet -dry) respectively, indicating that the distribution of Na, K, Mg, and Ca concentrations decreased from wet to dry season.These reported values in this study are within the acceptable WHO and SON limits (Table 5).The reason for the higher values of Na, K, Mg, and Ca in the wet season could be attributed to the higher dissolution of rock containing the minerals of these metals during the rains.Na, K, Mg and Ca were also detected in the groundwater samples of selected communities in the Isoko North Local Government Area, at lower than specified limits of the WHO and SON (Owamah et al., 2013).
The highest concentration of Zn (3410±1500 µg L -1 ) was obtained in July from a hand-drawn well water sample in GRA district of the study area.The concentration of Zn ranged from 60±30 µg L -1 to 3410±1500 µg L -1 and 60±10 µg L -1 to 2510±1300 µg L -1 for the wet and dry seasons respectively.For the seasonal mean values of Zn, 1320 µg L -1 and 275 µg L -1 were respectively obtained for wet and dry seasons.Only Zn of a HDW (3410±1500 µg L -1, wet season) and borehole (3010±1400, dry season) of GRA district surpassed the WHO (2006) and SON (2007) maximum acceptable limit of 3000 µg L -1 .Zinc usually comes into the groundwater through the erosion of Zn containing rock and soil minerals.Zinc is majorly introduced into ground water by artificial pathways.Though Zn is an important nutrient for body growth and development, high levels of zinc can lead to nausea, vomiting and stomach cramps (Owamah et al., 2013).The maximum concentrations of Pb of 300±20 µg L -1 was obtained from a borehole in OER district in the month of December.The minimum concentration of 10 µg L -1 was obtained from borehole and hand-drawn well water samples from YM, IT, GRA and LF districts.Pb was detected in various water samples of the boreholes and handdrawn wells across the six representative districts.Seasonal average concentrations of 28 µg L -1 and 41 µg L -1 for wet and dry seasons were respectively obtained.The concentration of Cd ranged from 10 µg L -1 to 80 µg L -1 for both wet and dry seasons with mean concentrations of 20 µg L -1 for wet season and 10 µg L -1 for the dry season.The concentration of Cu ranged from 20±20 µg L -1 to 2110±700µg L -1 in the wet season and from 10±20 µg L -1 to 1370±150 µg L - 1 in the dry season.The seasonal mean concentrations are 18 µg L -1 for wet season and 310 µg L -1 for dry season.Ba concentration ranged from 50±10 µg L -1 to 2510±440 µg L -1 in the wet season and from 40±20 µg L -1 to 1540±1540µg L -1 in the dry season.The seasonal mean values for Ba are 1275 µg L -1 and 380 µg L -1 for wet and dry seasons respectively.
Results are expressed as mean ± standard deviation; w = wet season; d = dry season; a =below detection limits.
Apart from Pb and Cd, the seasonal mean concentrations of the other metals found in the groundwater of the selected districts were below the WHO (2006) and SON (2007) stipulated limits for potable water (Table 5).Using ANOVA, no significant difference (P<0.005) in the values of metals for hand-drawn well and bore-hole water samples was obtained.The presence of slightly elevated levels of lead in a few samples in the study area could be as a result of the various oil explorations and processing activities within the subregion and careless disposal of various forms of electronic wastes and spent batteries on the soil (Owamah et al., 2013).The community also houses a flow station.According to Owamah et al. (2013), exposure to high levels of Pb can cause damage to the kidney and brain, and sometimes, make pregnant women to miscarry.Reports also show that elevated levels of Pb in kids could cause convulsion and neurological damages (USEPA 1991; Khan et al. 2013).In men, high concentration of lead can damage reproductive organs.Cd and its various compounds are reportedly, carcinogenic (Dahunsi et al., 2014;Khan et al., 2013).At high levels of exposure, Cd can cause vomiting and diarrhea but lower levels for longer period, can cause kidney impairment (USEPA 1977, Mkwate et al., 2017).Other health challenges associated with drinking water containing high levels of Pb and Cd are contained in Sojobi (2016).

Conclusion:
Groundwater in the community was found to be slightly polluted with metals of Pb and Ca, and with coliform bacteria.Samples from the hand-dug wells were noted to have higher values of these contaminants.Bacteria contamination was attributed to the poor disposal of solid waste (open dumps) and sewage, and the location of bore holes and hand-drawn wells close to pit-latrines and septic tanks.The slight metals contamination was linked to oil explorations and processing activities within the area of study and improper disposal of electronic wastes.While the concerned agencies and authorities should consider providing potable water for the people very important, household water treatment is Groundwater Quality Assessment in a University…..

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OWAMAH, HI recommended in the interim for the residents of the community.

Table 1 .
Mean concentrations of some physiochemical parameters of groundwater samples from the study area for wet and dry seasons (N=18) DO = dissolved oxygen; EC=Electrical conductivity; Results are expressed as mean ± standard deviation; w = wet season; d = dry season Egboh and Emeshili (2008)e values of the anions gotten in this study.Chloride concentration obtained ranged from 3 to 58 mg L -1 and 5 to 65 mg L - 1 for the wet and dry seasons respectively.Seasonal OWAMAH, HI mean values of 17 and 13 mg L -1 were recorded for wet and dry seasons, respectively.In line with the report ofEgboh and Emeshili (2008)of higher chloride concentrations in wet season for communities in the neighboring Ndokwa East Local Government Area, chloride values obtained were higher in hand-drawn wells and during the wet season.

Table 2 .
Mean values (mg L -1 ) of anions of groundwater samples from the study area for wet and dry seasons (N=18)Results are expressed as mean ± standard deviation; w = wet season; d = dry season; a below detection limits.

Table 5 .
Drinking water quality guidelines of the WHO and SON

Table 3 .
Mean values (µg L -1 ) of metals of groundwater samples from the study area for wet and dry seasons (N=18)