Assessment of Seasonal Variations of Heavy Metals and Microbial Parameters on Well Water Quality in Urban Centre, Effluent Locations and Non-Effluent Location of Kano Metropolis, Nigeria

: The groundwater consists of about 20% of the earth’s fresh water is the most widely used for drinking. Hence, the objective of this paper was to assess the seasonal variations of heavy metals and microbial parameters on well water quality in Urban Centre (UC), Effluent Locations (EL) and Non-Effluent Location (NEL) of Kano metropolis, Nigeria using appropriate standard techniques. The research collected 768 water samples from 48 wells at three different locations: Urban Centre (UC), Effluent Locations (EL) and Non-Effluent Location (NEL) in the city during dry and wet seasons in one year and subjected samples to laboratory analysis for determination of the concentrations of elements and bacteria in line with American Public Health Association (APHA, 2005). Higher mean values of Cadmium, Chromium, Mercury, Arsenic, Iron, Lead, Zinc, Manganese, Total Coliform and Escherichia Coli of 0.14mg/L, 5.11mg/L, 0.095mg/L, 0.15mg/L, 0.53mg/L, 3.1mg/L, 8.62mg/L and 4.1mg/L respectively at EL except Cadmium (UC). Analysis of Variance (ANOVA) and T-test 0.05% confidential level showed that Chromium F(2, 3) = 17.225, p =0.019, Arsenic F(2, 3) = 16.11, p = 0.031 and Iron F(2, 3) = 17.135, p = 0.021 while microbial parameters showed that E. coli F(2,3) =11.88 p = 0.038 parameters wells located at the UC, EL NEL areas of Kano. The results showed that heavy metal concentrations and microbial contamination in the metropolis are significantly different from each other where the mean level is significant at P<.05 across different locations, with higher levels found in industrial and urban areas during the rainy season. These findings highlight the need for improved management and monitoring of well water quality in Kano metropolis to protect public health.

One very important resource that occupies about 70% of the earth is water.Every life and the existence of ecosystem depend on water.Hence, the statement that water is life is absolutely germane.This fundamental resource exist on the surface of the earth in a form of oceans, seas, lakes, rivers, ponds, creeks, reservoirs and streams as well as underneath the surface known as groundwater in a form of well water and aquifers which provide water for drinking.United Nations Water (UN Waters 2019; Mshelia and Mbaya, 2024) reported that an estimated 2.2 billion in the world do not have access to portable drinkable water while 785 million people out of the 2.2 billion do not get fundamental water service.Additionally, about 44% MSHELIA, S. S; DADAN-GARBA, A; MBAYA, Y. A; BULAMA, L of the Sub-African population lacks clean drinkable and reliable water supplies (WHO, 2015;United Nations, 2019;Corcoran et al., 2010).The issue is not different in Nigeria; the Africa's populous nation of over 227.71 million people based on O'Neil (2024) population projection which reported about 64% also do not have access to good and drinkable water (UNESCO, 2016).The inability of the people to have access to clean water and other related services emanate from the pollution of the drinking water from point and non-point sources.In most cases, human activities trigger water pollution through the addition of impurities, feaces and other wastes from homes, industries, institutions, commercial centres and farms beyond the water carrying capacities of the substances culminating into scarcity of portable drinking water (Mshelia et al., 2020a;Global Water Security, 2012;Mshelia and Mbaya 2024;Kankara, 2019).Friedl (2013a) posited that the groundwater is the most widely used kind of water for drinking and it comprises of about 20% of the earth's fresh water which is mostly recharged by rainfall.Melting snow and leaks from lakes are the other sources of groundwater.When rain falls, great volume seeps into the ground and occupies the pores, fractures and other available spaces under the ground, passing through the unsaturated zones (the section underneath the ground surface contains water and air) and fills the aquifer layers also refer to as the saturated zones; the area that fully brimmed with groundwater.Groundwater is naturally, clean and good for consumption and other domestic uses for basically soil acts as a filter or sieve and makes the groundwater most often free of microorganisms such as bacteria that may cause diseases (Friedl 2013a;Mshelia 2024a).Nevertheless, Mshelia (2023;2024b) is of the view that human activities and geological processes can lead to contaminations of the groundwater.This can occur when toxic chemicals from industries, agricultural practices, households, communities and institutions are released into the environment and eventually seep or infiltrate into the groundwater.Similarly, wells located in swampy areas, dumpsites, wastewater canals, soakaways, filthy and wells without casings or caps are likely to get contaminated (Mshelia 2023;Audrey, 2019).Mshelia and Mbaya (2024) reported that three in every ten households in Kano Metropolis depend on well water for drinking and other domestic uses, however, it is very sad to note that most of the wells are located in filthy surrounding, close to toilet and near wastewater canals, thereby aiding in the recharge of the wells and gives room for possible contamination with common elements and microbial parameters.Contaminated well water may lead to health issue such as stomach disorders otherwise known as gastroenteritis, bloody diarrhea, hemolytic uremic syndrome, dysentery and cholera among others if consumed.Under severe situation, it could results to cancer, anemia and high blood pressure (Freidl 2013b;Mshelia, 2023).Therefore, good hygiene, sanitation and environmental management in every location of settlement are paramount.It is against these backdrops that the study investigated the spatial-temporal variations of heavy metals and microbial parameters on well water in three different locations of the metropolis attributable to human activities and geological processes with the view to proffering sustainable water management to meeting the 2015 Sustainable Development Goals (SDGs) 6: Clean Water and Sanitation (Mshelia et al., 2021;Mshelia et al., 2020).Hence, the objective of this paper was to assess the seasonal variations of heavy metals and microbial parameters on well water quality in Urban Centre (UC), Effluent Locations (EL) and Non-Effluent Location (NEL) of Kano metropolis, Nigeria.

MATERIALS AND METHODS
Study Area: Kano Metropolis is located between latitudes 11 0 55′ 23.93″N to 12 0 3′ 53.10″N of the Equator and longitude 8 0 27′ 42.26″E to 8 0 3′ 41.62″E of the Greenwich Meridian and encompasses total landmass of 499km 2 (see Figure 1).The city centre which is the urban area and the outskirt covering most parts of Kwombutso LGAs where Effluent and Noneffluent areas are located Mshelia, 2023).Well water samples were collected from these locations for laboratory analysis.The climate of Kano is tropical in nature according to Koppen's classification.The average annual temperature and rainfall is about 28 0 C and 700mm (NiMET, 2021).
Sample Collections: APHA (2005) methods were adapted for the collection of wells water samples at the three locations purposefully selected.These are: Urban Centre (UC), Effluent Locations (EL) and Non-Effluent Location (NEL) and water samples were collected from wells during dry and wet seasons as shown in Table 1.Eight (8) wells were systematically selected at each of the three locations where well water samples were collected 16 times at 1 week interval in 4 months during dry and wet seasons over a period of one year.Therefore, a total of 768 water samples at 48 locations were collected in the Metropolis (see Table 2) and subjected to laboratory analysis for the determination of heavy metals and microbial parameters.

Selection of Heavy Metals and Microbial Parameters:
Principal component analysis (PCA) using the SPSS statistics procedures was employed in the selection of the heavy metals for the determination of their concentrations in the three different locations in the metropolis owing to their capability of threatening water quality and eventually leads to health issues.The PCA produced Chromium (Cr), Cadmium (Cd), Mercury (Hg), Lead (Pb), Iron (Fe +2 ), Zinc (Zn) and Manganese (Mn) as well as Total Coliform Count (TCC) and Escherichia Coli (E.coli).
Laboratory Analysis: Heavy metals were determined using Shimadzu Atomic Absorption Spectrophotometer (AAS Model AA-6800), Japan model, equipped with Zeaman background correction and graphite furnace, Japan model at a temperature of < 4 o C. Different solutions of concentration standard were prepared to produce the calibration.Thereafter, the instrument was put on zero by running each reagent blank and metal concentrations determined three times and average values were taken.Microbial parameters determined are Total Coliform Counts (TCC) and Escherichia Coli (E.coli) using the Membrane Filter (MF) technique (APHA, 2005).T-Test (Formula tutorvista (2020).com/math/anovaformula.hmtl) .
(2)    The analysed results showed very high concentration of 0.15mg/L recorded in W4 and W3 during wet and dry seasons respectively (see Table 3 and 4) while higher Cr value of 6.86mg/L was reported in W7 at Yandanko during dry season at EL which can be ascribed to location of the wells very close to industrial effluent canals that gives room for easy seepage and infiltration of the wastewater into the well and compromise the water quality during wet season while low seepage was recorded during the dry season.In terms of spatial and temporal scope, the highest concentration values of Cd and Cr were recorded during the dry season attributable to less inflow of rainwater during the period to dilute the concentrated wastewater that eventually seeps into the wells as also reported by Benjamin and Eziashi (2017) in their work on sewage disposal effects on groundwater in Gombe.

RESULTS AND DISCUSSION
The analysis showed higher concentrations were recorded at EL such as Tarmuwa and Challawa industrial area (W3 and W5) and at UC such as Kofar Wambai, Fagge 2, Kofar Ruwa, Danmarke in W2, W4, W6 and W7 respectively as well as along the bank of River Jakara than at the NEL which comprises of the GRAs, Doctors Quarters, State House Road and sub urban areas of the Metropolis during the wet period characterized by well-planned layout and cleaned surrounding.
More still, W2, 3 and 5 recorded Hg mean value of 0.001mg/L within the WHO and NSDWQ limits of 0.001mg/L at UC during the wet season while all the wells at EL measured above the threshold (see Table 3  and 4).In terms of spatial locations higher values were obtained at the EL in both seasons than at the UC and the NEL where W7 at the Doctors' quarters, a NEL did not show any trace of Hg during the wet season, attributed to location within a clean environment with well covered lid.Similar finding was reported by James and Obukowho (2023) who studied domestic water quality in high institutions in Niger Delta region of Nigeria.The results on the Tables 3 and 4   The values are higher than the ones obtained at UC and NEL (see Table 3 and 4 All the P values recorded < .05which shows that there were significant seasonal variations among the three locations within the metropolis in well water during wet and dry seasons with higher values recorded during the wet period, attributable to runoffs during rainfall, high and low seepages, infiltrations, recharge and dissolutions during both seasons showing the effects of the influence of rainfall in the determination in the of water.The non-variations using ANOVA in Cr, Zn and Mn can be attributed to similar depth of wells, seepages, infiltrations and percolations rates, nonavailability of centralized wastewater collections system and treatment in the metropolis.Sankhla et al. (2016) who studied water contamination of heavy metal and hazardous health effects to human health in India also made similar observations.

Conclusion:
The assessment of spatial-temporal variations of heavy metals and microbial parameters on the quality of well water in Kano metropolis, Nigeria reveals significant changes over time.The presence of heavy metals, such as lead, arsenic, and chromium, can lead to health risks for individuals who consume contaminated water.Additionally, the microbial parameters, such as E. coli and total coliforms, indicate the presence of harmful bacteria in the water.These results highlight the need for proper monitoring and management of well water in Kano metropolis to ensure the safety and quality of the water for residents.Further research is needed to identify potential sources of contamination and develop strategies to mitigate these risks.Overall, this study provides valuable insights into the spatial-temporal variations of heavy metals and microbial parameters in well water and their implications for public health in Kano metropolis, Nigeria.

Fig
Fig 4.4: Kano Metropolis Source; GIS Unit, Geography Department, Federal University Gashua (2022) Source: FieldSurvey (2022)   MSHELIA, S. S; DADAN-GARBA, A; MBAYA, Y. A; BULAMA, L Statistical Analysis: The study employed the Analysis of Variance (ANOVA) and T-test for the analysis of the variability between spatial and temporal variations at 0.05% confidential level, Obeta and Ocheje (2013) Formula for AVOVA: correction for mean; SS (total) = total sum of squares; = (Sum of squares of all observations) cm = -cm; SST = sum of squares for treatment; = (sum of square of treatments totals with each square divided by the number of Observations for that treatment)cm; SS Sum of squares for error = SS (total)-SST; MST= mean square for treatments=SST/K-1; MS = mean square for error = SS1; F= test statistic =MST/ MS; Where n= total number of observations; K = Number of treatments; T1 = total of treatments I (i=1,2………k) S1 = standard deviation of first sets of the values; S2 = standards deviation of second sets of the values; n1 = standard deviation of first sets of the values; n2 = standard deviation of second sets of the values

Table 2 :
Summary of Well Water Collected in the Metropolis

Table 3 :
Mean Concentration of Heavy Metals on Well Water at Urban Centre in Kano Metropolis during Wet and Dry Seasons

Table 4 :
Mean Concentration of Heavy Metals on Well Water at Effluent Location in Kano Metropolis during Wet and Dry Seasons = 0.021 while microbial parameters on the other hand showed that E.coli F(2,3) =11.88 p = 0.038 parameters wells located at the UC, EL NEL areas of Kano metropolis are significantly different from each other where the mean level is significant at P<.05.Similarly, the T-test values in well water during wet and dry season reported (t(23)= 2.20, P < .05), (t(23)= 2.17, P < .05)and (t(23)= 2.24, P < .05) at UC, EL and NEL respectively.