Hand-dug Wells Research Articles

Delineation of the aquifer structure and estimation of hydraulic properties on the flanks of Mount Meru, Northern Tanzania

Understanding of the aquifer structure and its hydraulic properties provides comprehensive knowledge for proper groundwater utilisation and management. This study delineated the aquifer structure using litho-hydrostratigraphical cross-sections, and estimated the hydraulic parameters using single well pumping tests for various locations on and around Mount Meru. Results show that, the aquifer system on the flanks of Mount Meru is a sloping aquifer with sloping beds. On the far east of the eastern flank, the aquifer is composed of debris avalanche deposits, while on the north-eastern and west flanks the aquifer is composed of weathered fractured lava, whereas on the south-western flank, the aquifer is composed of different layers: pyroclastics on the top, weathered fractured lava, weathered pyroclastics, and weathered fractured lava at the bottom. The aquifer is semi-confined on the north-eastern and western flanks; on the north-eastern flank, the overlying debris avalanche deposits acting as an aquitard, while on the western flank, the overlying layers: pyroclastics and unweathered lava acting as an aquitard and aquiclude, respectively. The aquifer is unconfined on the far east of the eastern flank and south-western flank. The transmissivity of the aquifer on the north-eastern flank is substantially increasing with increasing depth, while variable, both at the shallow depth of hand-dug wells and the larger depth of boreholes, on the south-western flank; indicating aquifer heterogeneity. On the north-eastern flank, the topmost part of the aquifer, exploited by hand-dug wells, has a low transmissivity (T = 1.3 m2/d) and potential for smaller withdrawals for local water supply with limited consumption, while the upper part of the aquifer, captured by boreholes, has an intermediate transmissivity (T = 35 m2/d) and potential for local water supply, whereas the deeper part of the aquifer has a high transmissivity (T = 788 m2/d) with potential of somewhat regional importance. On the western flank, the aquifer has a very low transmissivity (T = 0.4 m2/d) and potential for local water supply with limited consumption. On the south-western flank, on average, the topmost part of the aquifer, exploited by hand-dug wells, has very low to intermediate transmissivity (range of T: 0.3–21 m2/d), leading to variable potential for smaller withdrawals for local water supply (private consumption), whereas the deeper part of the aquifer, captured by boreholes, has low to intermediate transmissivity (range of T: 9–43 m2/d) and potential for local water supply.

Concerning Human Health Risks of Trace Elements Contamination in Groundwater Sources nearby the Arabian Sea, Malvan Coastal Area, India

The current study looked at how heavy metals are distributed in groundwater and how they affect people's health during the pre-monsoon, monsoon, and post-monsoon seasons, water samples were collected from hand-dug wells and boreholes in the Malvan coastline and surrounding areas of Sindhudurg, MS, India's bordering the Arabian Sea. A total of 42 samples were collected and analyzed using standard methods for elements such as Iron (Fe), Zinc (Zn), Manganese (Mn), Copper (Cu), Fluoride (F), and Chromium (Cr). The data were analyzed using descriptive and inferential statistics. In the study area sampling location, the seasonal mean concentrations of heavy metals in groundwater samples (3 seasons) for Fe, Zn, Mn, Cu, Cr, and F were 1.39, 0.166, 1.148, 0.046, 0.008, and 0.509 mg/L, respectively. The metals were found in groundwater in the following order: Fe > Mn > F > Zn > Cu > Cr. The total Hazard Index (HI) of the metals in the groundwater samples revealed a high danger for people of all ages. In general, a high HI score (HI > 1.0) indicates negative non-cancer effects, with babies being the most vulnerable. For the studied metals, the cumulative cancer risk in the study areas is extremely low. The calculated health risk index indicates that Cr is high and the cancer risk on three categories such as Child, Adult and Infant is possible. Keywords: Seasonal assessment, Trace Elements, Groundwater contamination, human health risk, Malvan coastal area.

Water safety, antifungal-resistant aflatoxigenic aspergillus flavus and other pathogenic fungi in a community hand-dug wells.

To investigate hand-dug well water used for drinking and domestic purposes in a rural community in Southwest Nigeria for water safety and fungal presence as well as to determine the antifungal resistance and aflatoxigenic potentials of isolated fungi. Water samples were analysed for risk of contamination, bacteriological and mycological parameters using a standard sanitary survey checklist and microbiological culturing. Isolates were identified and subjected to antifungal resistance profiling using the diffusion method for susceptibility testing of filamentous fungi. Multidrug-resistant strains were confirmed with DNA barcoding identification. Fungal isolates were screened for aflatoxigenic potentials by culture methods and confirmed by densitometric analysis. From the 23 hand-dug wells assessed, 56.52% had a high risk of contamination (ROC) score, nitrate >50 mg/L (73.9%), and the presence of total coliforms (100%), Escherichia coli (43.48%) and fungi (91.3%). Spearman rank correlation coefficient gave a positive and strong correlation between Total Fungi and Faecal Coliform (r=0.701; p=0.016; n=23) at 0.05 significance level (2-tailed). Aspergillus sp. (34%), Penicillium sp. (18%) and Rhizopus sp. (17%) were the most dominant fungal genera. Isolates were resistant to fluconazole (76.19%), ketoconazole (73.80%), clotrimazole (92.86%), griseofulvin (88.09%) and nystatin (100%). Penicillium and Aspergillus (50%) were positive for cultural mycotoxin screening. A strain of antifungal-resistant A. flavus produced aflatoxin B1 (752 ppb) and B2 (15 ppb). The existence of antifungal-resistant and aflatoxigenic fungi in water used for drinking and domestic purposes shows that filamentous fungi constitute greater threats than previously recognized and this call for a paradigm shift from the perceived safety of untreated hand-dug well-water.

PRELIMINARY INVESTIGATION OF THE CHEMICAL QUALITY OF DOMESTIC WATER SOURCES IN SELECTED COMMUNITIES OF LANGTANG AREA, PLATEAU STATE, NIGERIA

A preliminary analysis of the chemical quality of domestic water sources in Langtang area was undertaken to determine variation in quality of water sources and how it meets the Nigerian Standard for Drinking Water Quality (NSDWQ). Using stratified random sampling technique, 50 water samples were taken from five different sources: rain, dams, streams, boreholes and hand dug-wells. Samples were tested in the laboratory for 20 parameters using standard methods described by USEPA (2012) and results subjected to ANOVA and independent sample t-tests. Temperature (28), turbidity (15), Ca (85), Mg (30), Cl (275), Fe (1.2), Pb (0.1) and Cd (0.002) had average mean above limits. ANOVA result shows significant variation in water quality with p-value of 0.001. Post-Hoc test revealed significant variation in 80% of the parameters tested: temperature, turbidity, EC, CaCO3, F, TDS, Ca, Mg, NO3, Fe, Cu, Al, Pb, As and Cd. Only pH, Cl, Mn, Cr and Zn do not show significant variation. Independent sample t-test also show significant variation in water quality to the Nigerian Standard for Drinking Water Quality (NSDWQ), which implies the water is unsuitable for human consumption. This study has demonstrated that despite differences in the protection levels of water sources, some parameters may still be the same across sources. It is therefore recommended that detail analysis of each water source be carried out to identify parameters responsible for pollution, as well as remediation the of water before consumption.

Spatial and seasonal water level dynamics in dryland grabens along the Rift Valley of northern Ethiopia

ABSTRACT We investigated water levels in semi-closed grabens of northern Ethiopia. Springs (n = 79), streamflows (n = 48), wetlands (n = 3), endorheic lakes (n = 3), hand-dug wells (n = 48) and boreholes in unconfined aquifers (n = 25) were monitored (2015–2017). Spring discharge fluctuates between wet (2.75 ± 1.5 L/s) and dry seasons (0.87 ± 0.21 L/s) (n = 68, p < .0001). Spring discharge and streamflow were larger at the foot of the escarpment than at the horst (p < .001). The water level of wells varied between horsts and escarpments in the grabens (p < .02). A water level depletion of up to 2.23 m/year occurred in response to withdrawals in the irrigated plains. Importantly, water level fluctuation was faster in streams, springs and hand-dug wells than in boreholes. Striking water level variations in the grabens were linked to rainfall deficit and management scarcity. An integration of surface water and groundwater management responses will bring the water table nearer to the surface; this could mitigate water storage in the fertile and productive grabens.

Spatial and Seasonal Drinking Water Quality Assessment in a Sub-Saharan Country (Guinea-Bissau)

The United Nations Sustainable Development Goal target 6.1 calls for universal and equitable access to safe and affordable drinking water. Worldwide, about 2.2 billion people live without access to safe water, and millions of people suffer from waterborne pathogens each year, representing the most pressing situation in developing countries. The aim of this study was to investigate the drinking water quality dynamics across an endemic cholera sub-Saharan country (Guinea-Bissau), and understand its implications for public health. Microbiological and physical–chemical quality parameters of 252 major water sources spread all over the country were seasonally surveyed. These comprised hand-dug shallow wells and boreholes, fitted with a bucket or a pump to retrieve water. The results showed that the majority of water sources available to the population were grossly polluted with faecal material (80%), being unsuitable for consumption, with significantly (p &lt; 0.05) higher levels during the wet season. Hand-dug wells revealed the highest contamination levels. The chemical contamination was less relevant, although 83% of the water sources were acidic (pH &lt; 6.5). This study highlights the potential health risk associated with the lack of potable drinking water, reinforcing the evidence for water monitoring, and the need to improve WASH (water, sanitation, and hygiene) infrastructure and water management in West African countries. In addition, the authors suggest easy-to-implement interventions that can have a dramatic impact in the water quality, assisting to reduce the associated waterborne diseases rise.

Physicochemical, bacteriological and water quality index assessment of hand dug well (HDW) water suitability for drinking

ABSTRACT Underground water were abstracted from HDWs to determine their suitability for drinking. Physical, chemical and bacteriological parameters were carried out following standard guidelines. Total coliform count was done using the membrane filtration method. Heavy metal was determined using an Atomic Absorption Spectrophotometer (AAS BULK SCIENTIFIC MODEL 210 VGP). Samples were subjected to statistical and multivariate analysis. Results of physicochemical parameters show that they were all within the WHO standard for drinking. Cation concentrations follow the order: Na+ > Ca2+ > Mg2+ > K+, while anions are: HCO3 − > SO4 2-> Cl−> NO3 − > PO4 2-. As, Cd and Pb were not detected in the sampled water, but other heavy metals Cr, Cu, Fe, Mn and Zn were detected. They were, however, within the WHO’s recommended range. Based on E. coli analysed, all of the water samples were free from faecal contamination since none was discovered in the water samples. Based on the water quality index, only sample G hand-dug well is of poor quality (though it could be treated) for human consumption; all other samples are good for human consumption. Deductions from Pipers’ and the Durov diagram, as well as principal component analysis, revealed that there was little geological and human activity within the hand-dug wells. Based on the physicochemical, microbiological, heavy metal and water quality indexes, this study indicates that all of the water samples examined are free of pollution, but that continual monitoring of the hand-dug wells should be prioritised.

Effects of water quality on rural livelihoods: a case of Tamale Metropolis

Water quality issues are a challenge in both developed and developing countries, which affects the people who depend on it. This study aimed at examining the quality of water sources used by the residence of 18 rural areas in Tamale Metropolis and their effects on their livelihoods. This was done by collecting water samples from four different sources used by residents: hand-dug wells, boreholes, Ghana Water Company Limited (GWCL) household tap and dam for laboratory analysis for both dry and rainy seasons. Furthermore, selected respondents from 18 communities in rural Tamale in the Northern region of Ghana who depend on these water sources were interviewed to examine the effect of the water sources on their livelihoods. From the findings, almost all households have access to at least 2 of these water sources with 51 percent of households storing water due to the lack of year-round water. The water quality test also shows that apart from water provided by the GWCL which passed the standard for physico-chemical parameters; dam, well, and borehole test results for colour (10.9-105.0 Hz), turbidity (23.5-226.0 NTU) and iron (0.35-1.99 mg/l) fell beyond the recommended range set by World Health Organization. No water source could meet the bacteriological requirements with a total (7-1910 CFu) and faecal (7-1200 CFu) coliforms content increasing in the rainy season. Seventy-three (73) percent of households reported sharing water with animals and 41 percent perceived to drink from unclean sources. Additionally, 70 percent indicated an increase in diseases such as cholera and diarrhoea while 90 percent responded that the cost of getting quality or potable water and attending for healthcare affects their household income. The overall implication is that the effect of poor water quality on the livelihoods of rural residence in Tamale Metropolis is significant and requires urgent intervention.

Potential cancer risk estimates from trihalomethanes in peri-urban settings of Kawama East of Mufulira, Zambia.

In this study, we report the formation and cancer risk estimation of trihalomethanes (THMs) emanating from 'ex-situ' chlorination of shallow hand-dug well water obtained from a peri-urban area of Mufulira District, Zambia. The aim of the study was to evaluate the potential cancer risks for people in this area where chlorine water disinfection at the household level is commonly practiced. Water samples from 13 randomly selected hand-dug wells (4-8 m deep) were collected and analyzed for pH, turbidity, and dissolved organic carbon before chlorination. Then another set of water samples from the same 13 wells was chlorinated using the methods commonly practiced in this area, consistent with WHO recommended doses. The chlorination degradation products, THMs, trichloromethane, bromodichloromethane (CHCl2Br), dibromochloromethane (CHClBr2), and tribromomethane, were determined at three different times of 60, 180, and 300 min after chlorination, while residual chlorine was determined immediately after chlorination and at 60 and 1,440 min after chlorination. THMs were determined using gas chromatography (GC), while residual chlorine was determined colorimetrically. Then cancer risk estimation from ingestion, inhalation, and dermal routes was carried out. All water samples from the 13 wells showed elevated amounts of THMs, which also increased with increasing contact time. For instance, the concentrations of THMs at 60 min after chlorination ranged from 24.3 ± 2.0 to 61.3 ± 1.0 μg/L, while at 180 and 300 min, ranged between 85.6 ± 4.3-146.9 ± 2.5 μg/L and 188.1 ± 7.1-250.1 ± 7.1 μg/L, respectively. It was observed that tribromomethane was not detected at all in all samples, while CHCl2Br and CHClBr2 were only detected at 180 and 300 min post chlorination. The lifetime cancer risk estimation results showed negligible risk at 60 min post chlorination. However, at 180 and 300 min post chlorination, the results were far above negligible, but within the regulatory US EPA limits. The overall risk, however, could not be ignored, given a multiplicity of exposure to various other contaminants, raising concerns over additivity and synergistic interactive effects, particularly for non-cancer hazard indices.

Analysis of Trace Metals in Hand Dug Wells around Dumpsites in Okene Metropolis, Nigeria

This study examined the levels of trace metals in leachates from dumpsites and hand dug wells used as sources of drinking water by the inhabitants of Okene Metropolis, Kogi State Nigeria. This is important because the presence of toxic heavy metals in the environment continues to generate a lot of concern to environmental scientists, government agencies and public health practitioners leading to adverse health implications. The leachates and hand dug well water samples were collected during the wet season of 2019-2021 and analyzed for some selected trace metals (Cd, Cu, Ni, Pb, Zn, Cr, and Mn) using AA320N atomic absorption spectrophometer. The result showed that there was high concentration of most of the trace metals in the leachate samples compared to the groundwater samples with some of the trace metals above the maximum limit set by W.H.O. It is recommended that a systematic treatment of heavy metals concentration in hand dug well in the study area should be carried out regularly either through chemical precipitation, ion exchange or reverse osmosis.

Hydrogeochemical evaluation and geospatial distribution modeling of the major ion chemistry of groundwater and their suitability for drinking and irrigation in Lagelu, Southwestern Nigeria

Shallow groundwater is an essential resource for domestic, agricultural, and small-scale industrial uses in Lagelu in Oyo State, Southwestern Nigeria. A total of 20 representative groundwater samples were collected from different hand-dug wells and analyzed for the major cations, anions, and heavy metals to establish their suitability for drinking and irrigation. Geospatial variation maps of the major cations and anions were produced using the inverse distance weighted algorithm. The results of the respective concentrations of pH, TDS, EC, HCO3−, NO3−, SO42−, Cl−, PO42−, Ca2+, Mg2+, Na+, K+, Zn2+, Cu+, Pb2+, and As+ except Fe2+ are within the recommended range set by the World Health Organization (WHO) and Nigerian Industrial Standards for Drinking Water Quality (NSDWQ). Based on the hydrogeochemical facies, the groundwater belongs to Na+–K+–Cl−–SO42−, and Ca2+–Mg2+–Cl−–SO42− water types. Gibb’s diagram shows that the interaction of rocks and water dominate the processes that control the ionic compositions of the groundwater due to rock weathering and dissolution. The correlation matrix that specifies the ion concentration relationship showed that TDS, K+, and Fe2+ strongly correlate positively with EC, Na+, and Ca2+, respectively. CO32−, Na+, and Cu moderately correlate positively with Cl−, Mg2+, and pH, respectively. The indices used to determine groundwater suitability for irrigation classified over 90% of the samples as suitable for irrigation.

ASSESSING WATER QUALITY AND THE NON-CARCINOGENIC HEALTH RISKS OF SURFACE AND GROUNDWATER IN IBI – TARABA STATE

The high concentration of chemical and biological contaminants in rural water is known to cause waterborne and water-related diseases. This study provides insights into the quality of surface and groundwater used for consumption and other domestic uses in Ibi environs. It further assesses the association between water quality variables and evaluates the chronic non-carcinogenic health risk using hazard quotient and hazard index. Thirty water samples each from the river and hand-dug wells were collected and the values of 17 variables were measured. The results showed that 58.8% and 35.3% of surface and groundwater failed to conform to national drinking water guidelines. The result for correlation between measured variables indicates both positive and negative correlation between variables across both water sources with pH negatively correlating with turbidity (r = -0.832) and TDS (r = -0.714) while temperature correlated positively with turbidity (r = 0.925), TDS (r = 0.793) and TH (r = 0.847). The results of human health risk show NO3- as the most dominant variable in inducing non-carcinogenic health risk in surface water while F- was the most inducing variable for groundwater. Based on the THI values, all the water sources showed long-term health risks above the safe limit even though some of the variables were within the national standards. There is therefore the need to address agricultural activities which is likely the major cause of nitrate in drinking water within the study region.

Evaluation of shallow groundwater in Rural Kebbi State, NW Nigeria, using multivariate analysis: implication for groundwater quality management

This study assessed shallow groundwater in rural Kebbi State using Pearson’s Correlation (r), Factor Analysis (FA), and Hierarchical Cluster Analysis (HCA). One hundred (100) shallow groundwater samples were drawn randomly from hand-dug shallow wells in 10 Local Government Areas (LGAs). Physical parameters (pH, temperature, TDS, EC, salinity) were analysed in situ using hand-held metres. Separate water samples were taken to analyse ions (Fe, Zn, K, Mg, Mg, HCO3, Ca). Results revealed that shallow groundwater is lightly acidic, except in Zuru and Fakai LGAs, where an alkaline condition occurred. Correlation analysis revealed that the dissolved solids in shallow aquifers result from natural geological and anthropogenic influences. However, FA had shown that most of the variability in shallow groundwater is influenced by natural geological factors with little evidence from anthropogenic inputs. The HCA categorised shallow groundwater into three groups: those shallow wells having higher concentrations of Zn and Cl with more elevated salinity and temperature; those shallow wells having very low salinity in central Kebbi State, and those shallow aquifers having alkaline waters. Except for higher Fe and Zn concentrations, the shallow aquifers contained water of excellent quality for drinking. Correlation analysis, FA, and HCA present simple statistical tools for assessing the hydrochemistry of groundwater.

English

This research investigates the microbial and physicochemical characteristics of five local hand dug wells used for drinking and agricultural activities in Blama, Small-Bo Chiefdom, in the Kenema District, Eastern Province of Sierra Leone. These five local hand-dug wells were randomly selected based on the availability of water in them throughout the year. The physical characteristics examined are: pH, turbidity, conductivity, temperature, total dissolve solid (TDS); and the chemical characteristics, such as: Residual chlorine (R. Chorine), magnesium, potassium, nitrite, iron, fluoride, ammonia, copper; and the microbial characteristics include: Total coliforms, fecal coliform and non-fecal coliform. Samples were collected in 500 ml sterilized plastic containers and transported to the laboratory, within 30 min. The results analysed indicate that the physical and chemical characteristic are within the WHO guideline limits for safe drinking water. However, a large amount of non-Faecal coliform was recorded in all the water samples analysed which exceed the World Health Organization standard for non-faecal coliform ((&lt;10), and with no presence of residual chlorine. It can therefore be concluded that the water sample analyzed was potable and fit for drinking and agricultural activities. Key words: Hand-dug, well, local, safe and sample.

Understanding recharge mechanisms and surface water contribution to groundwater in granitic aquifers, Ghana: Insights from stable isotopes of δ2H and δ18O

In hydrological studies, the use of stable isotopes (δ18O and δ2H) of water has proven to be a powerful tool to study groundwater recharge and mixing dynamics, which are critical to the long-term management of groundwater resources. In this study, we analyzed the stable isotopes of rain (event basis), groundwater (boreholes and hand-dug wells) and surface water in the White Volta River basin (Ghana). The aim is to understand the groundwater recharge processes, quantify the contribution of surface water to groundwater and assess the feasibility of artificial recharge in an agricultural catchment area. The results show that the event-based δ18O showed a weak dependence on air temperature (T) and rainfall (P) amount, while the monthly weighted average showed a much stronger correlation. The δ18O and δ2H show that rainfall is the main source of recharge and occurs in events greater than 10 mm. Overall, most of the groundwater falls between the June, July and August rains, suggesting that these months represent the recharge period. The groundwater isotopic variability is mainly influenced by local recharge and mixing with surface water. Low δ18O and high d-excess were found in most of the groundwater samples in the basin, indicating recent recharge conditions. The isotope mixing model shows that the surface water contribution to groundwater recharge is extremely variable, ranging from 1.47 ± 0.09% to 51.69 ± 6.04% suggesting the potential for artificial recharge. To summarize our results on the dynamics of groundwater recharge in the catchment area, we have provided a conceptual framework of our results.

Assessing the Quantity and Quality Controls of the Freshwater Lens on a Semi-Arid Coral-Limestone Island in Sri Lanka

Uncertainties in the contamination and salinization mechanisms of the freshwater lens (FWL) in the semi-arid coral-limestone aquifer of Delft Island, Sri Lanka threatens its water security. The processes governing the quality and distribution of the FWL were therefore investigated through recharge assessment and hydrochemical analysis. Potential groundwater recharge zones based on land classification and geology were first identified. A rootzone water balance model was then built, which revealed the spatiotemporal variability of potential groundwater recharge occurring rapidly during the wet season (October to January) and most abundantly on pasture land underlain by yellow and brown sand. Recharge also varied largely between dry and wet years. Where the water table was shallow, intense rainfall in wet years was seen to result in surface flooding. Geochemical modeling using PHREEQC combined with diagrams (Piper and Stiff) and scatter plots, including stable water isotopes, revealed the meteoric origin of groundwater with salinization mainly caused by seawater mixing and slight evaporation. Findings also suggest that salinization is driven by the island's low-lying nature (maximum elevation of 6 m above sea level), the low hydraulic heads (maximum of 3.7 m above sea level), the shallow depth of the marine water, the presence of lagoons in the center which are inferred to be in hydraulic continuity with the ocean, and to some extent by unregulated abstraction of groundwater through shallow hand-dug wells. We hypothesize about infiltration and percolation of saline water through the root zone during storm inundations near the coast, supported by the combined occurrence of high values of partial CO2 pressure, alkalinity and salinity in groundwater samples. Cation exchange showed indications of salinization of wells mostly in low lying areas (minimum Na/Cl value of 0.66), and freshening in areas near the coast with high potential groundwater recharge (maximum Na/Cl value of 1.04). Elevated nitrate concentrations (maximum of 2.55 mmol/L NO3-) in groundwater samples were observed. This suggests that anthropogenic contamination is further threatening the already scarce resource as well as coastal ecosystems that may be groundwater dependent.

Heavy Metal Pollution Levels of Hand-dug Wells in Close Proximity to Septic Tanks

The aim of this study is to evaluate the levels of selected heavy metal contamination in well water located in close proximity to septic tanks in the South gate area of the Federal University of Technology, Akure (FUTA). Water samples were collected from five (5) randomly selected hand-dug wells in the study area within 50ft (15.4m) distance to septic tanks. The physical attributes of the wells revealed that the wells were well constructed and all the wells sampled were lined with precast concrete pipe (PCP) rings with covers. Five heavy metals namely Cadmium (Cd), Chromium (Cr), Iron (Fe), Manganese (Mn) and Zinc (Zn) were analyzed in the laboratory using Atomic Absorption Spectroscopy. Cd, Cr and Mn were present in high concentration in some of the water samples evaluated exceeding the WHO permissible limit. However, Fe and Zn contents of the water fell within WHO standard for potable water. Secondary water treatment is recommended before human consumption. Keywords— heavy metals, potable, septic tanks, treatment, water samples.

Determination and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface and ground waters from Ifite Ogwari, Anambra State, Nigeria

ABSTRACT Levels of Polycyclic Aromatic Hydrocarbons in surface and underground water sources from Ifite Ogwari, Ayamelum Local Government Area of Anambra State were investigated. Ecological and human health exposure risks were assessed following US EPA methods. The surface water sources are Isiachala, Iyiutu, Ube, Ahala Tabasi, Nabaloku, Atammele, Ogbu streams, and Omambala river. Underground water sources include Igbazine, Double, Ogba, Onowulugbe, Orator, and Commodore hand-dug wells. The water samples were collected using precleaned 500 cm3 glass bottles and were analysed for the presence of 16 US EPAPAHs using Gas Chromatography – Flame Ionisation Detector (GC- FID). The validated method showed that regression (R2) for all the PAHs ranged between 0.9622 and 0.9983. Limits of detection (LOD) ranged from 0.0033 to 0.1236 µg L−1 and limits of quantification (LOQ) from 0.0109 to 0.4115 µg L−1. Precision CV values ranged from 5.12 to 18.24%, and recovery values of the analytes in water varied between 83.94 and 99.99%. Naphthalene and chrysene were present in all the water samples while pyrene was absent in all except in Iyiutu. All the PAHs analysed were detected in Isiachala and Iyiutu except pyrene which was absent in Isiachala. All the samples contained at least three PAHs with concentrations ranging from 1.003 ng/µl of benzo[a] pyrene in Tabasi to 128.652 ng/µl of chrysene in Iyiutu. Ecological risk shows that the value was above US EPA background value. Human health risk assessment depicts that hazard index and total cancer risk ranges from 9.63E-05 to 1.93E-02. This study has shown that the inhabitants of Ifite Ogwari will experience adverse health and cancer illnesses over some time and therefore, a holistic approach by researchers and government agencies is needed to mitigate the ecological and health risk effects.

Evaluation of Microbiological Quality of Water, Sediment and Soil Characteristics in Okrika Local Government Area, Rivers State, Nigeria

Water is the most important resource on earth and safe drinking water is essential to sustain life. Most rural communities do not treat their water before consumption. Therefore, the aim of this study was to evaluate the microbiological quality of water, sediment and soil characteristic in Okrika LGA, Nigeria. Samples were collected using sterile bottles from boreholes, hand-dug wells, surface water, sediments and soils using standard methods and analysed accordingly. Results show that Total Heterotrophic Bacterial Count (THBC) ranged from in Kalio-Ama to at Okari-Ama. Total Fecal count (TFC) ranged from 0 to at Isaka Town. Total Coliform Count (TCC) ranged from 0 to at Ogan-Ama. Total Salmonella Shigella Count (TSSC) ranged from 0 to in Ogan-Ama. Total Vibio Count (TVC) ranged from 0 to at Kalio-Ama. The most prominent bacterial isolates from all the stations are of the genera such as Bacillus, Staphylococcus, Escherichia Coli, Micrococcus, Kiebsiella, Pseudomonas, Vibrio, Aeromonas, Serratia and Alcaligenes which were isolated across the samples with Bacillus as more frequent with 50%. In the dry season, bacterial isolates were 100% susceptible to Gentamycin and Ofloxacin and 100% resistance to Augumentin, Cefuroxime and Cefixime. In the wet season, isolates had 100% susceptibility to Ciprooflozacin and 100% resistance to Cloxacin, Augmentin and Gentamicine. The result of this study poses a public health risk to consumers who use these sources of water for domestic purposes, recreation and treatments. Diseases like typhoid, cholera, polio, skin and lung infections are eminent.

Toxic Metal Concentrations in Drinking Water and Possible Effect on Sex Hormones among Men in Sabongida-Ora, Edo State, Nigeria.

Drinking water can be a potential source of toxic metals, which are a known leading cause of infertility in men. This study determines the concentrations of lead (Pb), cadmium (Cd), zinc (Zn), copper (Cu) in drinking water (borehole, hand-dug well and treated water) and sex hormone levels (serum follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PROL), estradiol (E2), progesterone (PROG), and testosterone (T) in males who drink water mainly from these sources. The concentrations of Cd, and Pb in hand-dug wells were higher than the permissible limit recommended by the World Health Organization (WHO) while Zn and Cu were within the permissible levels in drinking water. Blood Cd and Pb levels were significantly higher (p < 0.001) among subjects who consumed hand-dug and borehole water than treated water, while serum Zn was significantly lower (p < 0.001) in hand-dug well and borehole water consumers than in control subjects. Also, serum FSH (p < 0.001), LH (p < 0.001), E2 (p < 0.002), PROG (p < 0.04) and T (p < 0.001) were significantly lower among hand-dug well and borehole water consumers than controls, while PROL (p < 0.001) was significantly higher in hand-dug well and borehole water consumers than controls. Blood Cd and Pb levels were significantly higher (p < 0.001) in hand-dug well water consumers than borehole water consumers. The consumption of water from hand-dug wells may have adverse reproductive sequelae among consumers.