Drinking Water Quality Guidelines Research Articles

Effectiveness of the upscaled use of a silver-ceramic (silver ionization) technology to disinfect drinking water in tanks at schools in rural India.

In many low- and middle-income countries, school children consume untreated water that has been pumped into storage tanks. The water is often of poor quality and consumption can cause gastrointestinal illnesses resulting in missed school days, growth stunting, and cognitive impairment. This study deployed a silver-ceramic technology (MadiDrop) to disinfect drinking water in school storage tanks. While silver ionization is effective at the household scale, relatively little research has been conducted on its effectiveness at the community scale. To address this gap, we assessed disinfection via MadiDrop at three schools that serve vulnerable populations in rural India. Tank inflow and treated outflow samples were tested for total coliforms (TCs) and Escherichia coli (EC). TC was significantly reduced overall and in two of three intervention tanks. Compared to the baseline, reductions in TC were significant in all three tanks and overall, while EC reductions were significant overall and in two of three tanks. TC reduction was negatively correlated with silver concentration and tank residence time, and silver concentrations were maintained below the drinking water quality guideline. While the intervention could be considered successful, several barriers and caveats are provided as are study limitations and areas for future research.

Short Communication: Rotavirus Group A Occurrence in Rural Water Source Samples in a Midwest Region State of Brazil, Comparing Wet and Dry Seasons.

Identified as a potential reference pathogen by the WHO Guidelines for Drinking-Water Quality, Rotavirus (RV) is among the main enteric viruses that cause waterborne diseases. The aim of this study was to identify and correlate the presence of RV in collective and individual water sources of rural communities in the state of Goiás, within the seasons in which the collections were made (rainy and dry seasons). For this, 86 water samples in the dry period and 160 samples in the rainy period were collected. Concentration of water samples, extraction of viral genetic material and molecular tests were performed. When analyzing the presence of RV in the samples, taking into consideration the period studied, RV was found to be more prevalent in the dry season (54.7%) than in the rainy season (20%), showing a strong statistical association with the dry season (p-value < 0.001). The presence of pathogenic microorganisms in water is a public risk issue, enabling the emergence of outbreaks, endemics and epidemics. In the present research, there was an association between the presence of Rotavirus and the dry period of the year when compared to the rainy period.

Analysis of Spatial Bacteriological Quality Variation of Domestic Water Source Points in Mbarali District, Tanzania

This study assessed the bacteriological quality of water source points for domestic use. The study was conducted at Mbarali District, which is found in the Mbeya region of Tanzania. Eight wards were selected for water sampling, which were Mawindi, Ubaruku, Rujewa, Chimala, Ihahi, Mapogoro, Igurusi, and Mahongole. The eight wards were chosen because their waters are highly polluted. All samples were properly sampled and transported the same day to the TARI Uyole Laboratory for chemical and biological analysis. In-situ physical parameters were tested in the field using multiparameter equipment. Using GIS software, a spatial bacteriological quality variation of domestic water source points was analyzed and presented. For testing Escherichia coli (E. coli), Total Coliform, and Total Heterotrophic Bacteria (THB), 60 samples of water were taken from 8 wards and put through a membrane filtration method. 75% of the water source points found to be less than 20 meters away from residential areas were observed to be associated with bacterial contamination. The mean concentrations of E. coli, total coliforms, and THB were 2.5 CFU/100 ml, 10.36 CFU/100 ml, and 70 CFU/100 ml, respectively. There was a significant difference between CFU of total coliforms in samples collected (p = 0.026). About 80% of the samples collected and analysed for water quality parameters did not conform to the TBS and WHO drinking water quality guideline value of no detection per 100 ml. The study concludes that domestic water point sources found in Mbarali District are located less than 20 meters away from residential areas, with significant unpaved areas and the presence of septic tanks and pit latrines that may lead to water pollution. Unsafe drinking water in Mbarali District is the primary route for waterborne disease transmission. Therefore, we recommend treating the water from dug wells and rivers/streams in Mbarali District before drinking it.

Radiological assessment of radon in groundwater of the northernmost Kashmir Basin, northwestern Himalaya.

This study investigates the radon concentration in groundwater in Kupwara, the northernmost district of the Kashmir valley. It further assesses the annual effective dose experienced by the district's diverse population-infants, children, and adults-attributable to both inhalation of airborne radon released from drinking water and direct ingestion. In addition to this, the calculation of gamma dose rate is also carried out at each of the sampling site of radon. A portable radon-thoron monitor and a portable gamma radiation detector were respectively employed to estimate the activity concentration of radon in water samples and to measure the gamma dose rate. The radon concentration was found to exhibit variability from a minimum of 2.9BqL-1 to a maximum of 197.2BqL-1, with a mean of 26.3 BqL-1 and a standard deviation of 23.3BqL-1. From a total of 85 samples, 10.6% of the samples had radon activity concentrations exceeding the permissible limits of 40BqL-1 set by the United Nations Scientific Committee on Effects of Atomic Radiations as reported by UNSCEAR (Sources and effects of ionizing radiation, 2008) and only 1.2% of the samples have radon activity concentration exceeding the permissible limits of 100BqL-1 set by the World Health Organization as reported by WHO (WHO guidelines for drinking-water quality, World Health Organization, Geneva, 2008). The mean of the annual effective dose due to inhalation for all age groups as well as the annual ingestion dose for infants and children, surpasses the World Health Organization's limit of 100μSvy-1 as reported by WHO (WHO guidelines for drinking-water quality, World Health Organization, Geneva, 2008). The observed gamma radiation dose rate in the vicinity of groundwater radon sites ranged from a minimum of 138nSvh-1 to a maximum of 250nSvh-1. The data indicated no significant correlation between the dose rate of gamma radiation and the radon levels in the groundwater. Radon concentration of potable water in the study area presents a non-negligible exposure pathway for residents. Therefore, the judicious application of established radon mitigation techniques is pivotal to minimize public health vulnerabilities.

NTP monograph on the state of the science concerning fluoride exposure and neurodevelopment and cognition: a systematic review.

Fluoride is a common exposure in our environment that comes from a variety of sources and is widely promoted for its dental and overall oral health benefits. Contributions to an individual's total exposure come primarily from fluoride in drinking water, food, beverages and dental products. A 2006 evaluation by the National Research Council (NRC) found support for an association between consumption of high levels of naturally occurring fluoride in drinking water and adverse neurological effects in humans and recommended further investigation. The evidence reviewed at that time was from dental and skeletal fluorosis-endemic regions of China. Since the NRC evaluation, the number and location of studies examining cognitive and neurobehavioral effects of fluoride in humans have grown considerably, including several recent North American prospective cohort studies evaluating prenatal fluoride exposure. In 2016, the National Toxicology Program (NTP) published a systematic review of the evidence from experimental animal studies on the effects of fluoride on learning and memory. That systematic review found a low-to-moderate level of evidence that deficits in learning and memory occur in non-human mammals exposed to fluoride. To conduct a systematic review of the human, experimental animal, and mechanistic literature to evaluate the extent and quality of the evidence linking fluoride exposure to neurodevelopmental and cognitive effects in humans. A systematic review protocol was developed and utilized following the standardized OHAT systematic review approach for conducting literature-based health assessments. This monograph presents the current state of evidence associating fluoride exposure with cognitive or neurodevelopmental health effects and incorporated predefined assessments of study quality and confidence levels. Benefits of fluoride with respect to oral health are not addressed in this monograph. The bodies of experimental animal studies and human mechanistic evidence do not provide clarity on the association between fluoride exposure and cognitive or neurodevelopmental human health effects. Human mechanistic studies were too heterogenous and limited in number to make any determination on biological plausibility. This systematic review identified studies that assessed the association between estimated fluoride exposure and cognitive or neurodevelopmental effects in both adults and children, which were evaluated separately. The most common exposure assessment measures were drinking water concentrations and estimates of total fluoride exposure, as reflected in biomarkers such as urinary fluoride. In adults, only two high-quality cross-sectional studies examining cognitive effects were available. The literature in children was more extensive and was separated into studies assessing intelligence quotient (IQ) and studies assessing other cognitive or neurodevelopmental outcomes. Eight of nine high-quality studies examining other cognitive or neurodevelopmental outcomes reported associations with estimated fluoride exposure. Seventy-two studies assessed the association between fluoride exposure and IQ in children. Nineteen of those studies were considered to be high quality; of these, 18 reported an inverse association between estimated fluoride exposure and IQ in children. The 18 studies, which include 3 prospective cohort studies and 15 cross-sectional studies, were conducted in 5 different countries. Forty-six of the 53 low-quality studies in children also found evidence of an inverse association between estimated fluoride exposure and IQ in children. Existing animal studies provide little insight into the question of whether fluoride exposure affects IQ. In addition, studies that evaluated fluoride exposure and mechanistic data in humans were too heterogenous and limited in number to make any determination on biological plausibility. The body of evidence from studies in adults is also limited and provides low confidence that fluoride exposure is associated with adverse effects on adult cognition. There is, however, a large body of evidence on associations between fluoride exposure and IQ in children. There is also some evidence that fluoride exposure is associated with other neurodevelopmental and cognitive effects in children; although, because of the heterogeneity of the outcomes, there is low confidence in the literature for these other effects. This review finds, with moderate confidence, that higher estimated fluoride exposures (e.g., as in approximations of exposure such as drinking water fluoride concentrations that exceed the World Health Organization Guidelines for Drinking-water Quality of 1.5 mg/L of fluoride) are consistently associated with lower IQ in children. More studies are needed to fully understand the potential for lower fluoride exposure to affect children's IQ.

Upcycling process of mill scale waste into high-value ceramic products

Ceramic industry consumes large amounts of raw materials, including costly and environmental impact iron based-pigments. Steel rolling (SR) and wire drawing (WD) waste, rich in iron (>67 wt %), present a viable alternative. This study aims to develop high value stoneware pastes for tableware products by substituting commercial pigments with SR and WD. The influence of incorporation content (3, 5 and 10 wt %) and pre-treatments (sieving at 250, 150 and 63 μm, and grinding followed by sieving at 63 μm) on the samples properties was assessed including weight loss, firing shrinkage, apparent density, flexural resistance, and water absorption. The laboratory scale results revealed that darker hues, ranging from grey to reddish, were obtained when SR and WD were incorporated in the stoneware paste (beige colour). The smaller the particle size, more homogeneous is the developed colour, which is intensified as higher is the incorporation level.The prototypes (plates) were characterized in terms of thermal shock, edge impact, cracking and microwaves resistance, water absorption, and leaching behaviour, demonstrating that they met the industrial requirements. Thermal shock resistance was enhanced and the levels of leached Fe, Pb, Cd, Ni, Cr, Mo, V, Zn, and Cu, were below permissible limits (EU Ceramic Directive 84/500/EEC, Decree-Law n°152/2017, Decree-Law n°236/98 and WHO Guidelines for Drinking-Water Quality) confirming their effective immobilization. Concluding, this work shows the viability of using mill scale waste as a valuable secondary raw material in stoneware pastes acting as a chromophore agent. Dark colours are obtained while preserving the product technical characteristics, promoting sustainable production and reducing landfilled waste.

Groundwater Hardness and Alkalinity As Risk Factors for Kidney Stone Disease in Alwar, India: An Ecological Study.

Rajasthan is a semi-arid state in India where people still use groundwater for drinking purposes. However, the quality of groundwater as compared to standards have not been studied in any details. This ecological study was done to study the groundwater quality parameters in the stone-belt states, compare the quality of groundwater in Alwar with the rest of Rajasthan, and study the morbidity profile of surgical in-patients in the same district, with special emphasis on kidney stone disease (KSDs). The morbidity profile of patients coming to the surgery department of a tertiary teaching hospital between January 2002 and June 2023 was obtained from the medical records department, and water quality data was obtained from the publicly available Water Resources Information System (WRIS) groundwater dataset for the year 2023. The dataset provided detailed information on the chemical parameters of water samples throughout the country that were evaluated to estimate the quality of groundwater. It was found that the groundwater in Alwar is non-potable due to the presence of iron, alkalinity, magnesium, and total dissolved solids (TDS). Iron was estimated to be much higher than the acceptable limit of the Bureau of Indian Standards (BIS) drinking-water quality guidelines (0.3 mg/L). Similarly, most of the chemical parameters in the groundwaters of Rajasthan significantly exceeded the national average. The median electrical conductivity, fluoride, magnesium, sodium, hardness, alkalinity, and turbidity were found to be 1680 μS/cm, 1.05 parts per million (PPM), 41 PPM, 233 PPM, 330 PPM, 310 PPM, 988 PPM, respectively, which are above the WHO recommendations for drinking water guidelines. The levels of iron and total alkalinity were significantly higher in the study district as compared to the rest of the state. Also, magnesium hardness and TDS levels were very high in the groundwater of the entire state of Rajasthan, making the population vulnerable to KSDs in the long run.

Addressing challenges of BiVO4 light-harvesting ability through vanadium precursor engineering and sub-nanoclusters deposition for peroxymonosulfate-assisted photocatalytic pharmaceuticals removal

In this study, we present a complex approach for increasing light utilisation and peroxymonosulfate (PMS) activation in BiVO4-based photocatalyst. This involves two key considerations: the design of the precursor for BiVO4 synthesis and interface engineering through CuOx sub-nanoclusters deposition. The designed precursor of ammonium methavanadate (NH4VO3, NHV) leads to reduction in particle size, better dispersion and improved light harvesting ability, confirmed by the calculations of the local volume rate of photon absorption (LVRPA) using the Six-Flux Radiation Absorption-Scattering model. The morphological changes result in a significant improvement in photocatalytic activity under visible light for the degradation of pharmaceuticals (naproxen and ofloxacin) compared to the commercial NH4VO3. Additionally, CuOx sub-nanoclusters were deposited on designed BiVO4 and characterised using X-ray absorption near edge structure (XANES). The presence of sub-nanoclusters enhanced charge carriers separation, resulting in an increase in the apparent rate constants of 1.60 and 3.32-times for photocatalytic NPX and OFL removal, respectively. The application of obtained Vis light active photocatalysts in the presence of 0.1 mM PMS resulted in remarkably more efficient degradation of NPX (100 % within 60 min) and OFL (98.2 % within 120 min). PMS/Vis420/CuOx/BiVO4 system exhibited high stability and reusability in the subsequent cycles of photodegradation. However, high PMS dosage induced Bi leaching which may cause the instability of the photocatalyst. Finally, to address the environmental implications of pharmaceutical removal and adhere to the Guidelines for drinking-water quality, toxicity assessments using Vibrio fischeri bacteria were performed and compared to a quantitative structure–activity relationship (QSAR) model.

Impact of source water quality on total organic carbon and trihalomethane removal efficiency in a water treatment plant: A case study of Upper Awash, Ethiopia.

This study addresses the limited understanding of factors affecting the efficiency of water treatment plants in reducing trihalomethane (THM) formation through total organic carbon (TOC) removal, highlighting significant challenges in improving treatment effectiveness. The aim of this study was to examine the influence of water quality on the efficiency of water treatment plants to remove TOC and reduce THM formation. Linear regression and correlation analyses were conducted to examine the relationship between water quality parameters and THM concentrations. The results showed that there was a negative relationship between turbidity, metals, and TOC concentration with TOC removal efficiency. Positive correlations were found between parameters and the formation of THMs in water. Of these parameters, water temperature was observed to have relatively less influence on THM formation. It was observed that seasonal variations in water quality affect the efficiency of TOC removal and THM content in treated water. THM levels in chlorinated water were found to be within the permissible range of the World Health Organization's drinking water quality guidelines. However, it is still important to maintain continuous monitoring and take measures to reduce THMs. The model demonstrated a strong correlation (R2 = 0.906) between predicted and measured THM values.

Appraising groundwater quality and probabilistic human health risks from fluoride-enriched groundwater using the pollution index of groundwater (PIG) and GIS: a case study of adama town and its vicinities in the central main Ethiopian rift valley.

This research's main objective is to identify the level of contamination in drinking water in Adama town and its environs by employing PIG, GIS and HHRA. The physical-chemical parameters of groundwater were determined, and the results were compared to regional and global drinking water quality guidelines. The pH of groundwater is alkaline, and the contents of Ca2+, Na+, HCO3 -, and F- in the majority of samples surpassed the permissible drinking limit. The hydrochemical facies were identified in the following order: Ca-Mg-HCO3, Na-Ca-HCO3, and Na-HCO3. Cation exchange and Rock-water interaction are the major dominant natural mechanisms controlling groundwater chemistry. Using IDW interpolation methods with Arc GIS 10.8, spatial analysis of the physico-geochemical content of water divulged that TDS, pH, TH, EC, Mg2+, Ca2+, K+, Na+, Cl-, HCO3 -, F-, and SO4 2- all exhibit a positive trend in the direction of groundwater flow from the upland to the lowland (rift floor). As per PIG, the results show that 57%, 33%, 7% and 3% of the samples were found in the insignificant, low, moderate and high, correspondingly. The total hazard index (THI) is calculated from hazard quotients (HQIntake and HQDermal) results showing 83%, 73%, and 57% of the samples exceed the non-carcinogenic health threat of fluoride THI >1 in drinking water for children, women and men. Children are more susceptible to danger than either males or women, according to the THI data, based on body weights and consumption rates. Similarly, females are also more vulnerable to health risks than men.

Development of a tool to support operationalising water safety plans: experiences from a national water utility in Ghana.

Since their incorporation into the 2004 version of the World Health Organization's (WHO's) Guidelines for Drinking Water Quality (GDWQ), Water Safety Plans (WSPs) continue to be the pre-eminent process for the delivery of safe drinking water to consumers. WSPs achieve this by prioritising proactive, rather than reactive, management of risks to drinking water quality. Since the use of WSPs was incorporated into the GDWQ, a range of supporting resources have been produced to assist water suppliers in preparing WSPs. Producing a robust WSP is an important first step in the management of risk, but in many cases, the implementation of WSPs presents significant challenges, particularly in relation to the implementation of Module 5 (implementing improvements) and Module 6 (monitoring of control measures). To address barriers to WSP implementation, the Ghana Water Company Limited (GWCL), in a peer-to-peer partnership with two Australian water utilities, developed a pilot WSP implementation strategy for one of the company's drinking water supply systems. One of the outputs of the collaboration was the development of a framework for operationalising water safety planning, which incorporates basic guidance for embedding the WSP within routine operations, in order to ensure the safe management of drinking water.

Spatial distribution of drinking and irrigation water quality in different climatic zones of Baluchistan, Pakistan.

Baluchistan's water profile was developed by dividing it into seven zones (Northern Highlands-NH, Southern Highlands-SH, Quetta Valley-QV, Desert-D, Sibbi Plains-SP, Coastal Lasbella-CL, Coastal Gwadar-CG) based on geography, water availability, and climate of the area. A total of 106 water samples were collected from karaiz, spring water, and tube wells. Spatial distribution of EC, TDS, TH, SO42-, Cl-, Na+, and K+ showed an increasing trend in concentration from the highlands towards the desert and coastal zones. For anion, HCO3- is predominant in NH, SH, and QV, Cl- in D, CL, and CG and only SO42- in SP, whereas the cationic trend in overall zones is Na+>Ca2+>Mg2+>K+. In the NH, SH, QV, and SP zones, the physicochemical parameters met the drinking water quality guidelines; however, D, CL, and CG exceeded in almost all quality parameters. Furthermore, the drinking water quality index (WQI) shows excellent to good water quality in NH, SH, QV, and D zones, while CL and CG fall in poor to unsuitable water classes. In terms of hydrogeochemical facies, maximum water samples from NH fall in Ca-Mg-HCO3, and SH, QV, and SP in Ca-Mg-Cl type, where major ion chemistry is controlled by rock-weathering, while D, CL, and CG fall in the NaCl type, where evaporation is dominant. Similarly, irrigation water quality parameters (EC, SAR, RSC, Na%, MH%, PI, SSP, and KR) reveal that NH, SH, QV, and SP have suitable water for irrigation, and D, CL, and CG require proper treatment. Additionally, USSL and Wilcox's diagrams indicated that NH, SH, QV, and SP have "excellent to permissible"; however, D, CL, and CG have "permissible to unsuitable" class water, requiring special management practices. Consequently, appropriate control measures and targetedwater purification programmes should be implemented to protect the publichealth and sustainability of water resources inBaluchistan.

Assessment of spring water quality of Khandbari Municipality in Sankhuwasabha District, Eastern Nepal.

The study was carried out in the Khandbari Municipality, Sankhuwasabha District, Eastern Nepal to document the spring location and assess the water quality of the spring water for drinking and irrigation purposes. A total of 85 springs were mapped, which are located from 274 to 2176 m in altitude. Spring water samples were collected from 33 springs in the pre-monsoon (November, 2021) and 31 springs in the post-monsoon (March, 2022). Correlation matrices, t-test, principal component analysis (PCA), Piper diagram, Gibbs diagram, water quality index (WQI), United States Salinity Laboratory (USSL) diagram, and Wilcox diagram were applied for evaluating the spring water. All the physicochemical parameters were within the Nepalese National Drinking Water Quality Standard (NDWQS) and drinking water quality guidelines of the World Health Organization (WHO) except for pH in the pre-monsoon and iron in the post-monsoon season. The main contributors to the groundwater are Na+, Ca2+, Cl-, total dissolved solids (TDS), and total hardness, which exhibit significant correlations with electrical conductivity (EC) similar to TDS, suggesting their common source of origin. Based on the WQI, spring water is excellent in the post-monsoon and excellent and good in the pre-monsoon season. Furthermore, the spring water is excellent for irrigation purposes except for thepercent sodium in the post-monsoon and the magnesium ratio in the pre-monsoon season. Gibbs diagram illustrates that spring water is mainly governed by rock and precipitation dominance in some springs. The PCA indicates that anthropogenic activities (mixing of human waste and agricultural run-off in the spring water) are the main causes of contamination. Piper trilinear diagram demonstrates carbonate dissolution and silicate weathering as major processes for controlling the spring water chemistry. The study reveals that 62.5% of spring water was contaminated with microbes. For benthic macroinvertebrates, 18 springs were sampled, where nine orders and 17 families were recorded in the pre-monsoon and six orders and ten families in the post-monsoon season. The main influencing variables for macroinvertebrate assemblages are elevation, discharge, NO3-, and NH3.

Drinking water quality and associated factors in Bahir Dar City and the surrounding rural areas, Northwest Ethiopia: a community-based cross-sectional study

Abstract In low-income countries like Ethiopia, waterborne illnesses have posed serious public health problems. This study aimed to evaluate drinking water quality (DWQ) and associated factors in Bahir Dar City and the surrounding rural areas in northwest Ethiopia. A cross-sectional study was conducted from January to June 2022 to determine coliform counts and basic physicochemical parameters from the drinking water samples (DWS) collected from urban, peri-urban, and rural sites. A total of 180 DWS were collected from water collection points and households' containers. Potentially pathogenic bacteria were also isolated from fecal coliform (FC)-positive samples and their antibiotic susceptibility profiles were determined. Moreover, the risk factors associated with water quality were assessed. The water quality test results were evaluated against the WHO guidelines for DWQ. Based on the results of this study, only 16.7 and 73.88% of samples met the standards for total coliform and FC, respectively. Moreover, 95.4 and 43% of the isolated bacteria were resistant at least to one of the commonly used antibiotics and multidrug-resistant, respectively. Educating the public on proper drinking water handling, appropriate treatment, and waterline maintenance are needed to safeguard the community from waterborne diseases.

Assessment of Borehole Water Quality in Usmanu Danfodiyo University Sokoto (Permanent Site), Nigeria

It is acknowledged that access to high-quality water is crucial for any significant human development. Ten boreholes were used in obtaining the water sample. The samples were analyzed using the American Public Health Association (APHA) suggested procedures. The test parameters were compared to the chemical drinking water quality guideline established by the World Health Organisation. In a situation where the value is not provided, we relied on other pieces of literature. The research shows that the alkalinity, iron (Fe+), calcium (Ca2+), magnesium (Mg+), nitrate (NO3-), pH, conductivity, phosphate (PO43-), and total hardness (CaCO3) are all in line with the guidelines permissible limit which means are within the no-problem zone limits for health. While copper (Cu2+) was found to be within the permissible limit 2 mg/L in all the samples but BH1 (Junior Staff Quarters) 3mg/L which has health problems such as digestive disturbances, problems with the central nervous system, mucosal irritability, Wilson's illnesses, and liver and kidney damage.

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Silicon is one of the most common elements in the earth’s crust. It is always present in water and food in varying amounts. Higher amounts of Si are found in plant-based foods. About 20% of the total amount of silicon ingested with food and water comes with drinking water and drinks (including beer, which contains in average 20–25 mg/l of silicon)․ For higher animals and humans, silicon is generally not considered to be an essential nutrient. However, the importance of this element for human health is now supported by increasing research evidence. The biological role of silicon in human organism is still not clear, but it assumed to be necessary for processes of bone mineralization, collagen synthesis. It has a positive effect on the skin, hair, and nails, contributes to the prevention of atherosclerosis and Alzheimer disease. In the population of most Western countries, dietary Si intakes range from 20 to 50 mg/day. In addition to the beneficial effect of Si on health, questions regarding the adverse effect of this element on the body are also discussed in the literature. First of all, we are talking about the Russian authors’ researches in the field of drinking water hygiene. At present, the adequate and maximum admissible levels of Si consumption have not yet been established. Taking into account the results of research on humans and animals, some scientists have suggested a dietary intake of Si of about 25 mg/day. As for the standards of silicon content in drinking water, it is not regulated in the drinking water quality guidelines of the WHO and the European Union, as well as in the national normative documents of different countries. In the Russian Federation, as well as in the Republic of Armenia, in the hygienic requirements for water quality, Si is normalized according to the sanitary-toxicological index, with the value of the maximum admissible concentrations in drinking water amounting to 10 mg/l.

Groundwater fluoride and nitrate contamination and associated human health risk assessment in South Punjab, Pakistan.

Consumption of high fluoride (F-) and nitrate (NO3-) containing water may pose serious health hazards. One hundred sixty-one groundwater samples were collected from drinking wells in Khushab district, Punjab Province, Pakistan, to determine the causes of elevated F- and NO3- concentrations, and to estimate the human health risks posed by groundwater contamination. The results showed pH of the groundwater samples ranged from slightly neutral to alkaline, and Na+ and HCO3- ions dominated the groundwater. Piper diagram and bivariate plots indicated that the key factors regulating groundwater hydrochemistry were weathering of silicates, dissolution of evaporates, evaporation, cation exchange, and anthropogenic activities. The F- content of groundwater ranged from 0.06 to 7.9mg/L, and 25.46% of groundwater samples contained high-level fluoride concentration (F- > 1.5mg/L), which exceeds the (WHO Guidelines for drinking-water quality: incorporating the first and second addenda, WHO, Geneva, 2022) guidelines of drinking-water quality. Inverse geochemical modeling indicates that weathering and dissolution of fluoride-rich minerals were the primary causes of F- in groundwater. High F- can be attributed to low concentration of calcium-containing minerals along the flow path. The concentrations of NO3- in groundwater varied from 0.1 to 70mg/L; some samples are slightly exceeding the (WHO Guidelines for drinking-water quality: incorporating the first and second addenda, WHO, Geneva, 2022) guidelines for drinking-water quality. Elevated NO3- content was attributed to the anthropogenic activities revealed by PCA analysis. The high levels of nitrates found in the study region are a result of various human-caused factors, including leaks from septic systems, the use of nitrogen-rich fertilizers, and waste from households, farming operations, and livestock. The hazard quotient (HQ) and total hazard index (THI) of F- and NO3- showed high non-carcinogenic risk (> 1) via groundwater consumption, demonstrating a high potential risk to the local population. This study is significant because it is the most comprehensive examination of water quality, groundwater hydrogeochemistry, and health risk assessment in the Khushab district to date, and it will serve as a baseline for future studies. Some sustainable measures are urgent to reduce the F- and NO3- content in the groundwater.

Groundwater Quality Assessment in Urban Areas of Malawi: A Case of Area 25 in Lilongwe

Groundwater sources provide an important supply of alternative drinking water in most urban areas in Malawi. This study was conducted to assess the quality of groundwater in Area 25, a typical urban residential area in Malawi. Samples were collected from wells and analyzed for physicochemical and bacteriological parameters following standard methods. Results were compared to Malawi Standards (MS) and World Health Organization (WHO) drinking water quality guidelines. The overall water quality index was computed to ascertain the general quality of the water. Levels of pH, phosphate, sulfate, arsenic, lead, and potassium were below the guideline limits while, electrical conductivity, total dissolved solids, chloride, fluoride, nitrate, total hardness, calcium, and magnesium were observed above permissible limits, posing a health risk to the residents. The quality index ranged from 22 (excellent quality) to 64 (Poor quality) with an average of 41 (good quality). Fecal coliforms were present in 70% of the sampled locations with an average of 7.9 cfu/100 ml. The presence of these bacteria presents a serious risk for waterborne disease outbreaks. This study, therefore, recommends the provision of basic treatment techniques to improve the quality of water in the area before consumption, regular monitoring of groundwater resources, and proper design and setting of septic systems.

Cluster and multivariate analysis to study the diffuse contamination of emerging per- and polyfluoroalkyl substances (PFAS) in the Veneto Region plain (North-eastern Italy)

In recent years, per- and polyfluoroalkyl substances (PFAS) have emerged as major pollutants of concern. This study considered a real case of superficial and groundwater contamination caused by a set of 15 persistent, carcinogenic, and bioaccumulative compounds. The study area is the Veneto Region floodplain in Italy, where a huge contamination mainly caused by a persistent spill-over from a former chemical factory was discovered in 2013. The contamination path studied in 2013 followed mainly two directions: the first towards east, to the city of Vicenza, and the second following the course of Chiampo and Agno streams, southwards.To identify the major patterns of contamination, a Factor Analysis (PCA) in conjunction with a Cluster Analysis (CA) was performed. The reviewed dataset is composed by PFAS concentration values collected from 2013 to 2021 in groundwater, superficial waters, in natural sources, and in proximity to three industrial discharges, throughout a 3600 km2 area. The CA results were cross-referenced with the water table interpolation, yielding a match between the groundwater flow directions and the observed patterns of the two main plumes. The persistence of pollutants was finally investigated by analyzing distances between the former chemical factory, an industrial wastewater collector which lies along Chiampo and Agno valleys that host residential and industrial areas, and the other sampling points collected in the dataset. The findings confirmed the importance of assessing anthropic background levels of contamination and highlighted the necessity to include the PFAS issue in a national health-based drinking water quality guideline.

Determination of Heavy Metals in Water Samples within the Southern Part of Kaduna State, Nigeria

This paper investigated the presence of heavy metals in water samples from three selected sites in the southern part of Kaduna State, Nigeria. Twelve (12) samples were analysed at the Federal Ministry of Agriculture and Rural Development, Kaduna using Atomic Absorption Spectrophotometer (AAS). Levels of some heavy metals, Zn, Cu, Mn, Fe, Ni, Cr, Cd, Pb, Ca, Mg, Na and K were determined in water samples collected from the research area. The results obtained show that, the recorded mean values of Zn, Cu, Mn, Cd and Mg were within the WHO/GDWQ guidelines; while Na and Ca recorded mean values below the World Health Organisation (WHO)/Guidelines for Drinking- Water Quality (GDWQ) minimum mean value, Ni, Fe, Cr and Pb were found to be considerably high in the water samples, which exceeded the WHO/GDWQ maximum mean value. Therefore, the result shows the presence of heavy elements in the sampled area. The low mean values of Ca and Na within the sampled area could lead to poor bone formation risk like rickets among the populace. While consumption of such vital elemental nutrients is recommended, it is however advised that the populace should avoid consumption of Ni, Fe, Cr and Pb in high content above the stipulated WHO/GDWQ guidelines.