Nigerian Standard For Drinking Water Quality Research Articles

Efficiency of Ceramic Composite Filter Produced Using Nano Particulate Carbonaceous Material

Millions of people have no access to safe water. This has led to continued incidence of waterborne diseases with severe cases of complications and sometimes death. Attempts to use silica sand-based materials for the production of filters by researchers are still evolving. In this study a novel hybrid clay-nanoparticulate agro-waste blend water filter with appropriate pore size and flow rate for contaminant-free water filtration was produced. The composite filters were produced using hydraulic pressing and sintering process. Four different ratios of clay, activated carbon and nanoparticle coconut shell (60:30:10, 60:20:20, 60:10:30, and 60:0:40 wt %) were mixed and fired at 700 °C, 750 °C, 800 °C, 850°C, 900 °C, 950 °C, and 1000 °C respectively at the rate of 75 °C/hr. E. Coli, Total Coliform, and turbidity tests were carried out on the influent water collected from Lagos Lagoon, and effluent water samples were filtered using the produced samples. The result of water tests revealed that all the filters produced removed between 86.81 % to 99% Escherichia Coliform (E. coli), and 81.81% to 93.31%% total coliform in the water sample. The blend of 60:10:30 fired at 850 °C and 900 °C showed improved properties with a flow rate value of 2.83 l/hr and 2.77 l/hr. In conclusion, the study established that synthesis of nanoparticle coconut shell and activated carbon is a suitable material for producing clay composite filters that can purify water to Nigerian Standards for Drinking Water Quality (NSDWQ) acceptable level.

ASSESSMENT OF HEAVY METAL CONTAMINATION AND HEALTH RISK ASSOCIATED WITH SELECTED BOREHOLE WATER PROXIMAL TO A DUMPSITE IN GIWO, BAUCHI STATE

Water quality is a critical concern for human well-being and ecological stability, particularly as groundwater serves as a vital source of freshwater globally, sustaining various societal sectors. Human activities have increasingly polluted groundwater with contaminants, notably heavy metals, presenting potential health hazards to communities reliant on these water sources. This study investigates heavy metal contamination in borehole water samples from four distinct locations within Giwo, Bauchi State, Nigeria, and evaluates the associated long-term health risks of consuming this water. Analysis of the water samples identified iron to have the highest concentration (1.140 mg/L) while lead recorded the lowest concentration (0.0003 mg/L), the concentrations of zinc and copper across all the four locations were within the Nigerian Standard for Drinking Water Quality (NSDWQ) established by the Nigerian Industrial Standard (NIS) of 3.0 mg/L and 1.0 mg/L. The Average Daily Intake (ADI) from water consumption for, zinc, iron, copper, cadmium, and manganese were consistently below their corresponding Reference Doses (RfDs) of 0.3 mg/kg/day, 0.7 mg/kg/day, 0.04 mg/kg/day, 0.0005 mg/kg/day, and 0.14 mg/kg/day, respectively for all water samples analyzed while the remaining heavy metals exhibited ADIs exceeding their established RfDs. Hazard Quotient (HQ) values for most metals were below the threshold of 1, suggesting a relatively low risk of adverse health effects. However, prolonged consumption of this water may heighten cumulative health risks associated with specific heavy metals, warranting continuous monitoring and remedial actions.

Environmental Assessment of Heavy Metal Pollution around Industrial Area in Southwestern, Nigeria

This study investigated heavy metal contamination around an industrial district in Obajana, Southwest Nigeria. The study region lies between latitudes 7°54′N to 7°56′N and longitudes 6°24′E to 6°27′E. Thirty samples each for groundwater and soil and twelve plant samples were collected from the study area. All samples were collected in triplicate. The physical and chemical parameters of the groundwater, soil, and plant samples were measured. The average pH level of the groundwater samples is 7.2 which falls within the Nigerian Standards for Drinking Water Quality (NSDWQ). The ranges of the other physical parameterssuch as electrical conductivity (EC), total dissolved solids (TDS) and total hardness (TH) are also within the acceptable limits. The mean concentrations of heavy metals in groundwater samples for Mn (0.020 mg/L), Zn (0.010 mg/L), Ni (0.010 mg/L), Cr (0.130 mg/L), Cu (0.020 mg/L), and Fe (0.090 mg/L) are within the allowable limit, with the exception of Pb (0.090 mg/L) that is above the recommended level. According to the index of geo-accumulation (Igeo), the soil and plant samples are not polluted with respect to the heavy metals tested. The analysis of the human risk assessment reveals that the values for the carcinogenic risk are within acceptable bounds; however, the values for the non-carcinogenic risk are substantially above the acceptable bounds. This demonstrates that non-carcinogenic health impacts are a threat to the broader population. This study suggests continuous monitoring of groundwater, soil, and plant in the study area.

Evaluating the seasonal variations of risks associated with potentially toxic elements in underground water sources near a dumpsite in Awka, Nigeria

Contamination of borehole water by leachates from dumpsites has significantly affected the health of those who use polluted water for domestic activities. This study evaluated the seasonal variations of risks associated with potentially toxic elements in underground water sources near a dumpsite in Awka, Nigeria. The levels of the potentially toxic elements (PTEs) were compared with the World Health Organization (WHO) and Nigerian standard for drinking water quality (NSDWQ) standard limits. The, sources of PTEs, metal pollution index, water quality index, ecological risk, and health-related risks of using the underground water were evaluated. The chemical results indicated that levels of Cd and Pb were above the WHO and NSDWQ threshold limits for potable water. The Mn and Ni values were above the NSDWQ limits for potable water. The study borehole samples had PTE levels higher than the control samples due to their proximity to the landfill. The water quality index ranged from 1290.29 to 2243.04, showing that the water is unsuitable for drinking and other domestic uses. The metal pollution indices of the underground water samples were above 1, indicating that the water needs treatment before use. The health risk examination highlighted that children are more disposed to non-cancer risk than adults based on the hazard indices obtained. Also, the probability of cancer risks was high, showing that both children and adults are likely to be in danger of cancer risks. However, the ecological risk indices ranged from 11.187 to 51.581, indicating a low ecological risk. Pearson's correlation and principal component analysis revealed that the sources of pollution are from similar origins/sources linked to anthropogenic activities. Awareness programs are necessary to educate the populace about the dangers of using contaminated water. Effective waste management strategies and water treatment techniques should be implemented.

Evaluating Groundwater Safety: Heavy Metal Contamination of Selected Boreholes across Uyo Metropolis, Akwa Ibom State, Nigeria

Study’s Novelty/Excerpt This study offers a comprehensive analysis of heavy metal concentrations in borehole water within Uyo Metropolis, Akwa Ibom State, highlighting significant public health risks associated with these contaminants. Utilizing Atomic Absorption Spectrophotometry (AAS), the research uniquely identifies iron and nickel concentrations that exceed World Health Organization (WHO) and Nigerian Standard for Drinking Water Quality (NSDWQ) guidelines, with iron levels reaching 0.551 mg/L and nickel levels at 0.298 mg/L. These findings emphasize the urgent need for policy interventions and infrastructure investments to mitigate the pervasive risk to consumers and ensure the safety of water resources. Full Abstract In light of growing concerns about water quality and its effects on public Health, this study offers an in-depth analysis of heavy metal concentrations in selected boreholes water within Uyo Metropolis in Akwa Ibom State. The research also emphasizes the potential health risks associated with these heavy metals, particularly as some have been found to exceed the acceptable drinking water limits set by the World Health Organization (WHO). Borehole water samples from ten strategically selected locations were collected and analyzed for heavy metals using Atomic Absorption Spectrophotometry (AAS) to quantify the concentrations of copper, zinc, iron, chromium, and nickel. The results revealed that all water samples contained iron concentration (0.551 mg/L), surpassing the guidelines set by the World Health Organization (WHO) and Nigerian Standard for Drinking Water Quality (NSDWQ), indicating a pervasive risk to consumers. Additionally, elevated levels of nickel (0.298 mg/L) were detected in several samples, further exacerbating the public health implications. The findings underscore the critical need for policy intervention and infrastructure investment to ensure the safety and sustainability of safe water resources for human use.

Assessment of physicochemical, minerals and microbiological qualities of borehole and well water: A case study of Akure Metropolis, Nigeria

Groundwater constitutes a substantial reservoir of fresh water utilized for agricultural irrigation and drinking, emphasizing the critical importance of safeguarding its availability and quality. Contamination of groundwater can arise from chemical, physical, or microbiological sources, each contributing to various health-related issues. In the region of FUTA Southgate, Southwest Nigeria, an assessment was conducted on the physicochemical and microbiological characteristics of groundwater from hand-dug wells and boreholes to ascertain its suitability for human consumption. The analysis indicated that parameters such as BOD, DO TS, TH, and nitrate content were within the acceptable limits set by the World Health Organization (WHO) and the Nigerian Standard for Drinking Water Quality (NSDQ). However, the presence of heavy metals like Fe, Cu, Cr, Pb, Mn, Cd, and Zn was detected using an atomic absorption spectrometer, revealing a slight level of contamination in both water sources. Furthermore, microbiological examination identified Total Coliform Counts of 382 cfu and 159 cfu in hand-dug wells and boreholes, respectively, indicating fecal contamination. The findings suggest that inadequate sewage systems and improper waste disposal practices contribute to the compromised water quality and elevated nitrate levels in hand-dug wells, rendering the shallow aquifer groundwater unsafe for drinking purposes across all evaluated parameters. Consequently, appropriate treatment and disinfection measures are imperative before utilizing the contaminated borehole and groundwater wells for human consumption or industrial purposes.

Seasonal Assessment and Design Using Water Quality Index for Drinking: A Case Study of Bali Town and Environs, Taraba State, Nigeria

This study addresses the critical issue of water quality in Bali town and its surroundings, with a specific focus on the seasonal variations in the Water Quality Index (WQI) for boreholes. Groundwater, crucial for drinking purposes, lacks adequate quality testing in the region, which poses potential health risks. Water samples collected during both wet and dry seasons in 2016 and 2017 were analyzed for twenty-nine parameters. However, only nine out of the twenty-nine samples were used in calculating the Water Quality Index for the boreholes under investigation. These nine parameters include Turbidity, Total Dissolved Solids, Total Hardness, pH, Nitrate, Copper, Iron, Chloride, and Total Coliform Count. When comparing the results with the standards set by the World Health Organization (WHO) in 2010 and the Nigerian Standard for Drinking Water Quality (NSDWQ) in 2007, it was observed that most parameters increased during the wet season, indicating higher pollutant dissolution. Notably, bacteriological parameters, especially the Total Coliform Count and E. coli, exceeded permissible limits. This highlights the urgency of water treatment to achieve excellent quality and provides valuable insights for designing water infrastructure.

SUITABILITY OF GROUNDWATER QUALITY FOR DRINKING USING WATER QUALITY INDEX IN KANO METROPOLIS, NIGERIA

Groundwater is an important source of drinking water in Kano Metropolis, Nigeria. This study aims to assess the suitability of groundwater for drinking using the water quality index (WQI). 960 water samples were collected from 160 sites in the Kano Metropolis and analyzed 9 physicochemical parameters, 9 heavy metals and two groups of microbial parameters using American Public Health Association standard procedures in a laboratory. The values obtained for the various parameters were then compared to the World Health Organization’s (WHO) and Nigerian Standards for Drinking Water Quality (NSDWQ). The overall WQI for each LGA was calculated using Weighted Arithmetic Index guidelines. The results showed that overall WQI is generally unsuitable for drinking with ranged values of borehole water from 47.07 - 149.51 in Dala and Nasarawa respectively while the well water ranged from 94.17 - 251.44 at Tarauni and Kumbotso and spatially represented in map of Kano metropolis. Marginally suitable for drinking were recorded at Dala and some individual wells in well-planned and clean areas (Bompai Quarters, GRAs). The T-Test statistical analysis between borehole and well in Dala, KMC and Nasarawa LGAs showed significant variations at P = < .05 while Fagge, Gwale, Kumbotso, Tarauni and Ungogo LGAs showed no significant differences. The study recommends the need for improved water management strategies, such as desalination and water treatment, to increase access to safe drinking water.

Evaluation of Geology and Hydrochemistry of Nawfia-Agulu Axis of Anambra State, Southeastern Nigeria

The investigation of the geological, hydrochemical, and engineering characteristics of the Nawfia – Agulu area was carried out. The study aimed at mapping the geology through field data collection, outcrop logging, and laboratory analysis. Consequently, eleven soil and ten water samples were collected and analyzed through particle size distribution test; Atterberg limits tests and hydrochemical analysis to provide insights into the lithology, sediment characteristics, and water quality. The results indicated the dominance of the Ameki/Nanka Formation and Imo Formation as the underlying geology of the study area. The grain sizes of the sand samples ranged from medium to coarse grained, moderately to poorly sorted, and strongly positive to positively-skewed. The depositional environment was nearshore/beach, influenced by nearshore waves and turbulent currents. Engineering properties highlighted the prevalence of uniformly to well-graded soil and moderately to highly plastic behavior, as indicated by the mean plasticity index (PI) value of 26%. These findings suggest potential challenges for infrastructural development in some parts of the area. The water quality indicated slightly acidic water. The physical parameters and the major ions were within the permissible limits of World Health Organization (WHO) and the Nigerian Standard for Drinking Water Quality (NSDWQ). However, elevated concentrations of heavy metals, including lead, chromium, mercury, iron, and cadmium, in water sources exceeded the respective permissible limits for drinking water indicating contamination/pollution. The dominant water type was Ca2+ – Mg2+– SO42- – Cl– and the dominant hydrochemical process was simple dissolution or mixing and ion-exchange.

Physicochemical Parameters of Ground Water Quality in Crown Estate and Its Environs in Okada Town, Edo State, Nigeria

The evaluation of drinking water quality mainly by determination of some physicochemical parameters present is of paramount importance due to the impact on human health. The present study presents investigation on the physicochemical parameters of ground water samples collected from selected boreholes, in Crown Estate and environs, in Okada, Benin City, Nigeria. Samples were collected from selected boreholes and pH taken and immediately taken to the laboratory to investigate some selected physicochemical characteristics. The mean concentrations of metals in the water samples followed a decreasing order: Zn (0.5122mg/l) > Fe (0.4378mg/l) > Mn (0.0594mg/l) > Ni (0.0358mg/l) > Cr (0.0302mg/l) > Cu (0.3000mg/l), Pb and Cd were below detection limit. The laboratory results of all the selected physico-chemical parameters analyzed when compared with the world health organization (WHO), National Agency for Food and Drug Administration Control (NAFDAC) and Nigerian Standards for Drinking Water Quality (NSDWQ) standards for water showed that all the selected Physicochemical parameters with the exception of iron (for NAFDAC) were within national and international standards limits for drinking water.

Groundwater contamination and its potential health risk in Oba community, Anambra State, southeastern Nigeria: an index analysis approach

The health risk associated with groundwater contamination of Oba community were studied. Water samples were collected from twelve boreholes, consumed by the inhabitants of the study area. Each sample was analyzed for 15 water quality parameters and the results indicated that all the groundwater samples were polluted with heavy metals (Pb, Co, As, Cr, and Cd). However, other physicochemical parameters of the samples (Cu, Cl−, NO3−, PO43−, SO42−, TSS, TDS, EC, TH, and Salinity) were within the Nigerian Standard for Drinking Water Quality (NSDWQ) and WHO. All locations' weight arithmetic water quality index, heavy metal pollution index, heavy metal evaluation index, and degree of contamination exceeded their critical pollution index values of 100, 100, 6, and 3 respectively. Cobalt in Ama-Enumah, Okpuno-Etiti, and Rando sample locations had HQder > 1 in both adults and children. Also, the study revealed that children had HIing > 1 in all sample locations when compared to their adult counterparts, suggesting non-carcinogenic health risks for children through oral intake. Hence, water from these boreholes should be treated before use for drinking and other domestic and irrigation purposes.

Investigating the quality of groundwater in Ibeju-Lekki Local Government Area, Lagos State

ABSTRACT This study assessed the groundwater quality in the rapidly urbanizing peri-urban region of the Ibeju-Lekki Local Government Area in Lagos State, Nigeria, during the rainy season. This study employed a two-stage sampling technique to select representative sampling locations, including boreholes and hand-dug wells. Seven towns in Ibeju-Lekki were sampled for this study. A total of 14 sampling points were chosen for the analysis of 15 water parameters, which included five physical parameters (NTU, TCU, E.C. TDS and TSS), eight (8) chemical parameters (pH, T.H. Ca, Mg, Cl-, NO3-, SO42- and Fe), and two (2) microbial parameters (E.Coli count and BOD) after standard procedures. The data obtained were subjected to statistical analysis using Python to assess correlations between the physicochemical parameters. The results were compared with water quality standards set by the World Health Organization (WHO) and the Nigerian Standard for Drinking Water Quality (NSDWQ). In addition, a water quality index (WQI) was calculated to provide a single numerical expression of the overall water quality. The findings revealed variations in the quality of borehole and well water, with some parameters exceeding the recommended standards, such as magnesium and iron concentrations. The presence of elevated turbidity, total dissolved solids (TDS), and electrical conductivity (E.C.) in well water indicated potential contamination sources. The study also demonstrated the significance of understanding physicochemical parameter correlations in groundwater quality assessment. The WQI results emphasized that groundwater is suitable for various purposes, including animals and other domestic and agricultural purposes. However, the paper recommended routine monitoring and thorough treatment to address the high magnesium (Mg) and iron (Fe) levels in both borehole and well water sources.

Evaluation of geophysical parameters for groundwater productivity in the Commune of Jesse, Delta State Nigeria


 Aquifer geohydraulic properties in Jesse were studied by the application of vertical electrical sounding (VES) and pumping test. The VES data was collected using ABEM SAS 1000 Terrameter and results processed using manual matching of curves and computer iteration, and interpreted in the forms of geologic models and geoelectric layers. The aquiferous unit was found at a depth of 5.30 m to 30.30 m with a range of resistivity from 87.30 Ω-m to 1945.40 Ω-m. Dar-Zarrouk parameters estimation and results of borehole pumping test produced the aquifer hydraulic parameters. The hydraulic conductivity values range from8.171 - 8.279 m/day, transmissivity from 43.8770 - 517.7480 m2/day, and formation factor from 0.369 - 8.501. These results are indications of a prolific and high yielding aquifer capable of withstanding long duration of pumping. Results of groundwater electrical conductivity and total dissolved solids ranged from 11.65 - 198.80 μs/cm, and 29.40 - 35.40 mg/dm3 respectively, signifying very moderate mineralization of the groundwater. The average electrical conductivity of 68.04 μS /cm and total dissolved solids of 32.58 mg/L were lesser than the acceptable limits of the Nigerian Standard for Drinking Water Quality (NSDWQ) of 1000 μS/cm and 500 mg/L respectively. This study affirmed that the aquifer in Jesse is suitable for groundwater exploitation for local and regional purposes.

Assessment of heavy metal contamination in groundwater from motorized boreholes in Maitumbi, Tipa Garage Area, Minna, Niger State

Discharged industrial effluent poses a significant threat to groundwater due to potential heavy metal contamination. Elevated levels of heavy metals in drinking water pose serious public health risks. This study aimed to assess the quality of drinking water from motorized boreholes in Maitumbi, Tipa Garage Area, Minna, Niger State, by measuring heavy metal concentrations using Atomic Absorption Spectroscopy (AAS) as the analytical tool. Water samples were collected randomly from ten (10) boreholes, and the concentrations of some environmentally common heavy metals (Pb, Cd, Hg, Cu, Ni, and Cr) were determined using an Atomic Absorption Spectrophotometer of PG Instruments Ltd. (Model AA500). The results showed high concentration levels for most of the observed metals, which exceeded the permissible limits by the Nigerian Standard for Drinking Water Quality (NSDWQ) and the World Health Organization (WHO). Generally, the study suggests that the water samples are not safe for drinking directly and recommends some level of tertiary purification to reduce the heavy metal concentration levels to make them safe for drinking.

Quality Assessment of Sokoto Water Distribution Networks

The research is on the quality assessment of Sokoto water distribution networks. Sample coordinates of the study area were taken using GPS, the experiments were carried out at different consumer locations with thirty (30) samples of water collected weekly for four (4) weeks, to determine various purification parameters that are related to both bulk (kb) and wall (KW) reactions coefficients for Sokoto water distribution pipe network, these include residual chlorine, pH, dissolved oxygen (DO), temperature and conductivity. pH, dissolved oxygen (DO) and conductivity have average values ranging from 6.7 to 7.5; 1.1 to 6.5ppm; 310 to 520 μs/cm respectively and conform to the Nigerian Standard for Drinking Water Quality (NSDWQ), except temperature which has the average values between 29 oC, and 32.6oC, and the individual values between 26 oC, and 38.4oC, chlorine residual average values obtained, ranging from 0.11mg/l to 0.26mg/l with the lowest individual value obtained being 0.011mg/l. The age of water supply from the treatment plants in the distribution network is 6 hours and both first and second-order decay reactions were ascertained from the graph and first-order decay having the highest number of occurrences was used in Epanet 2.0 water quality modeling. The kb values ranged from 0.0025 to 0.013md-1. A total of 86 out of the 120 samples, which constitute 71.7% were straight lines which indicate first-order and thus, the average kb was determined to be 0.006/day (0.144/hour). It was observed that of all the 120 samples examined in the study, chlorine reaction with natural organic matter (NOM) was small. The average kw for Sokoto WDS was deduced to be 0.078m/h, considering, the following steel pipe conditions used in the network area. kW (ft/h), -α =-38.5, H-W C=150, kW = 38.5/150 = 0.257ft/h = 0.078m/h (-0.078m/h).

Strategic Monitoring of Groundwater Quality Around Olusosun Landfill in Lagos State for Pollution Reduction and Environmental Sustainability

As urbanization and population increase in the megacity, there is a need for engineering intervention and strategic monitoring of groundwater around landfills for environmental sustainability, pollution reduction and public health. This study evaluated water’s physical and chemical parameters in wells and boreholes near the Olusosun landfill in Lagos State to determine how they impact groundwater quality. An Atomic Absorption Spectrometer (AAS) was used to evaluate groundwater samples obtained from five locations within the dump site. Some water parameters, such as dissolved oxygen (DO), iron (Fe), lead (Pb), manganese (Mn), and magnesium (Mg), had concentrations that were higher than the WHO, NESREA, and Nigerian Standard for Drinking Water Quality (NSDWQ) standard limits in some sampling sites, with mean concentrations of 0.33 mg.L-1, 0.04 mg.L-1, 0.74 mg.L-1, and 0.74 mg.L-1, respectively. A small amount of lead was identified in the groundwater of the study area. A major source of air and groundwater pollution, the Olusosun landfill has a detrimental impact on the health of those who live there. Solid waste, groundwater interactions, and contaminated migration into the nearby neighbourhood were studied. It was observed that the degradation of waste products in dump sites releases harmful leachate into the groundwater. Even though some heavy metal concentrations in the study area are still within WHO, NESREA, and NSDWQ standard limits, investigations and further monitoring should be conducted regularly to assess the concentrations of heavy metals in groundwater.

Assessment of variations in microbiological quality of water in the newly constructed rainwater-harvesting system storage tank

Proper harvesting of rainwater requires a good knowledge of the storage conditions and the nature of physico-chemical and microbiological contaminant loads on the harvested water. This will help to determine the nature and level of treatment required. This study assessed the variations in the microbiological quality of water stored in a newly constructed galvanized steel tank over the course of one rainy season in Afikpo, Nigeria. A 2.0 mm thick galvanized steel tank of 1.728 m3 capacity was constructed together with water collection system including coarse mesh, gutter, funnel, conduits, first-flushing device and filter. Rainwater was collected into the tank, sampled, discharged, and rinsed with chlorinated water at each sampling episode throughout the rainy season at Afikpo, from April to November 2021. The water samples were tested in the laboratory for total coliform and faecal coliform. The weekly concentrations of total coliform range between 90CFU/100 ml and 320CFU/100 ml; the mean is 177CFU/100 ml. The weekly concentrations of faecal coliform fall between 30CFU/100 ml and 261CFU/100 ml; the mean is 108CFU/100 ml. These results indicate that the concentrations of the two pathogens are far above the zero limit recommended by the World Health Organization (WHO) and Nigerian Standards for Drinking Water Quality (NSDWQ) . Hence, the rooftop-harvested rainwater is unsafe for human consumption without treatment. Boiling or chlorine treatment is needed. Public health authorities in Afikpo should sensitize the public on the dangers of consuming untreated rainwater as is the practice found among many in the area.

Assessment of Heavy Metal Content and Human Health Risk of Orogodo River, Delta State, Nigeria

The Orogodo River is a major source of water for drinking, cooking, bathing, fishing, washing and recreation for the resident community. Apparently, anthropogenic activities threaten the sustainability of this resource, hence, the need for environmental monitoring studies. This study was carried out to investigate heavy metal content and to assess human health risk of Orogodo River vis-a-vis its suitability for human consumption. Water samples were collected from four sampling stations established along the stretch of the river with the upstream station at Site 1, two midstream stations (Sites 2 and 3) and the downstream station being Site 4 and analyzed for seven heavy metals: iron (Fe), copper (Cu), manganese (Mn), chromium (Cr), nickel (Ni), zinc (Zn) and lead (Pb) concentrations using the atomic absorption spectrophotometer. The results obtained from the study showed that the mean values for Fe (2.77±0.00 mg/l) in Site 4, Ni (0.15±0.19 mg/l) in Site 2, Pb (0.05±0.02 mg/l) in Site 3, Mn (0.30±0.30 mg/l) in Site 3 and Cr (0.06±0.03) in Sites 2 and 3 exceeded the Nigerian Standard for Drinking Water Quality (NSDWQ) maximum permissible limits (Fe: 0.3 mg/l; Ni: 0.02 mg/l; Pb: 0.01 mg/l; Mn: 0.2 mg/l and Cr: 0.05 mg/l) for Nigerian freshwater and thus warranted health risk assessment. Health risk assessment for all sites indicated that with exemptions of Cr (1.33 in Sites 2 and 3 for children), other metals showed no potential health risk, but their cumulative effects as indicated by the hazard index (1.19 and 2.50 for adult and children in Site 2; 1.22 and 2.91 for adult and children in Site 3 and 1.36 for children in Site 4) could be of serious concern. This calls for caution for both adults and children exposed to the water through ingestion and the dire need for enforcement of water resource management regulations by the concerned authorities.

RISK ASSESSMENT OF PESTICIDE RESIDUES IN WATER SAMPLES FROM NWANIBA RIVER, AKWA IBOM STATE, NIGERIA

Ecological risk assessment of pesticide residues is not only germane but critical in view of their inherent health challenges and for informed decision-making process. This study was conducted to assess the levels of contamination of organochlorine pesticide residues in water from Nwaniba River in Uruan Local Government Area of Akwa Ibom State. The analysis was carried out using Gas Chromatography with electron capture detector (GC-ECD). The obtained results revealed the predominance of Dieldrin in the different samples of water analysed from Ufak Effiong in the Southern District (station I) and Akani Obio in Uruan Central District (station II) of Uruan. Pesticide levels were found to be significantly higher than the World Health Organization /Food and Agricultural Association (WHO/FAO) Maximum Residue Limits (MRL). The concentrations of organochlorine pesticides (OCPs) ranged from Below detection limit (BDL) - 2.37 × 10-1 ng/µL for water samples. Carcinogenic risk values for γ-BHC, delta-BHC, Dieldrin, Endosulfan I and Heptachlor epoxide in the water samples were found to be less than 1.0 × 10−5, thus posing no potentially serious cancer risk to consumers. The values of cancer risk obtained were lower (6.448 × 10- 11 and 7.208 × 10-11) than the established maximum limit. Hazard index (HI) values calculated for pesticide consumption through water by children and adults are all above unity, indicating that high toxic risks are associated with them. The HI values for children exposure are significantly lower compared to those of adults of Ufak Effiong and Akani Obio. This study reveals that the physicochemical parameters of water obtained from both stations were below the maximum permitted levels set by World Health Organization (WHO) and Nigerian Standard for Drinking Water Quality (NSDWQ). It also provides a baseline data and critical information to encourage effective monitory and management of the ecosystem.

Evaluation of Physiochemical Qualities and Microbiological Profile of Selected Hand Dug Well in Ado – Ekiti

Water is vital and one of the most important resources to the survival of all livings (both plants and animals). About 97% of the world’s 1.4 billion Cubic km of water is ocean water. Quality water is essential for economic development and ecological balance. However, the scarcity of water is on the increase, hence the need for proper and adequate planning, standard monitoring and proper management of water as one of natural resources. This research evaluates the effect of anthropogenic activities and domestic wastes on surface water quality in Ekiti State University Students’ Residential Area. The study determines water contaminants and the effects of water contamination to the health of students and all other residents in the study area. Primary and secondary sources of data collection were employed in the study. A total of 18 water samples (nine for microbial and physiochemical testing respectively) were obtained from the study area for laboratory analysis where physiochemical and microbiological tests were conducted. For the physiochemical tests, the organoleptic parameters include colours, turbidity, and odours, while the inorganic parameters include nitrate, Conductivity, pH, total dissolved solid, total hardness, total alkalinity, total acidity, chloride, Sulphate (SO4 ), Calcium, Magnesium (Mg +2 ), Arsenic (As), Cadmium (Cd), Chromium (Cr 6+), Copper (Cu+2 ), Iron (Fe+2 ), Lead(Pb), Manganese(Mn+2), Zinc (Zn), Dissolved Oxygen, Total Suspended Solid. Color and Odour of all samples were unobjectionable, pH values ranged from 6.03 – 6.17 with mean of 6.50, Conductivity values ranged from 135.4 – 607µs/cm with a mean value of 282µs/cm, turbidity values ranged from 1.0 – 8.0 NTU with the mean value of 3.8, Total Dissolved Solid (TDS) concentrations ranged from 30.5 – 376 mg/L having a mean of 180 mg/L, Total Hardness , Alkalinity and Total Hardness had respective values which ranged from 26.9 – 102.4 mg/L and 29.4 – 122 mg/L with the mean of 63mg/L and 75g/L respectively, chloride, Sulphate (SO4), Calcium, Magnesium(Mg+2), Arsenic(As), Cadmium (Cd), Chromium (Cr6+), Copper (Cu+2), Iron (Fe+2), Lead(Pb), Manganese(Mn+2), Zinc (Zn), Dissolved Oxygen values ranged from 3.24mg/L to 5.86mg/L, Total Suspended Solid values ranged from 0.058mg/L to 0.628mg/L. All the parameters were lower than limit as recommended by the World Health Organization (WHO) and Nigerian Standard for Drinking Water Quality (NSDWQ).