Assessment of ground water quality for drinking purpose, District Nainital, Uttarakhand, India

Evaluating health risks from the release of trace elements to groundwater by rock-water interaction in a weathered gneissic aquifer

High concentration of trace elements in groundwater poses more health risks to humans by drinking groundwater and dermal contact. This work aimed to assess the trace element concentration in groundwater, water quality for drinking purposes, and its effect on human health upon prolonged consumption. The study was carried out in the gneissic terrain of Perambalur District, Tamil Nadu, India, where groundwater is used mainly for drinking, agricultural, and domestic purposes. Hydrochemistry, water quality, and health risk assessments of trace elements from 44 groundwater samples for pre- and post-monsoon were determined by drinking water quality, hazard quotient, hazard index, and carcinogenic risk. The dominance of trace elements in groundwater was in the order of Zn > Fe > Cu > Ni > Te > Pb > Co. Ni and Co are released more during the post-monsoon, and Zn, Fe, Cu, and Pb concentration during the pre-monsoon. The dominant type of groundwater was Ca-HCO3 and mixed Ca-Mg-Cl type. The dissolution of fissile hornblende biotite gneissic rock dissolves more trace elements to groundwater than charnockite rock. The correlation matrix indicates that major ion and trace elements were positively good in groundwater during the pre-monsoon and post-monsoon 2018. The principal component analysis suggests that the weathering of rocks, rainwater recharge, and evaporation processes controlled the hydrochemistry of trace and major ions. The concentration of Pb, Ni, and Cd elements exceeded the permissible limit of BIS and WHO; these elements are unsuitable for drinking. The trace element concentration in groundwater was good for drinking and irrigation in the study area, except in a few wells. The hazard quotient and hazard index were computed, which revealed that non-carcinogenic risk to human health by drinking groundwater was more of a problem for children than adults. This study will help prevent children from health risks of trace elements.

Groundwater for drinking and industrial purposes: A study of water stability and human health risk assessment from black sand mineral rich coastal region of Kerala, India

Tempero-spatial analysis of groundwater to disseminate the level of drinking water quality and industrial suitability to meet the developmental requirement of a region is a significant area of research. Accordingly, groundwater quality and geochemical interactions prevailed in a black sand mineral rich coastal village is systematically presented in appraisal of drinking and industrial uses for economic engineering purposes. The study area focused is Alappad village, Kollam, Kerala, India has numerous ecological features in a sustainable perspective. The region is unique with placer deposits where an alluvial soil aquifer-saline water-freshwater interaction occurs. This dynamics decides the pertinent hydro geochemistry, potable and designated uses of ground water in season wise. Coastal area is hereby presented based on water quality parameters predicted with the health risk assessment model with a view on human health and cancer risk due to ions (Pb, Ni, Cu, Ba, Fe, Al, Mn, Zn) in groundwater.. To ascertain industrial usage, ground water is evaluated by Langelier saturation index (LSI), Ryznar stability index (RSI), Aggressive index (AI), Larson-Skold index (LS) and Puckorius scaling index (PSI) and inferences are complemented. Chemical weathering and evaporation processes are the natural factors controlling hydrochemistry of this aquifer. This complex coastal system has Nemerow pollution index (NPI) of moderate pollution for total dissolved ions of Fe and lesser for Cu, and Cr present in groundwater. LSI indicates, water is scale forming but non corrosive (46% in PRM, 20% in MON and 47% in POM). Water quality index (WQI) in POM (ranged 28.7-79.9) was excellent for drinking, followed by PRM (23.6-218.2) and MON (33.4-202.7) seasons. This groundwater bears temporary hardness with the dominance of Ca-Mg-HCO3 water type. Health risk assessment of non-carcinogenic risk index of trace metals (Fe, Zn, Mn, and Pb) revealed, children are at 'low risk' and 'medium' risk with Ni and Cu. The carcinogenic risk index indicated 93% of samples were high Ni induced cancer risk for children, and 87% for adults due to long term ingestion (drinking water intake) pathway. Studies specific on placer mineral deposited coastal region of India are not sufficiently reported with a focus on the above perspectives. Growing need of rare earths for material, device and energy applications, placer mineral explorations can destabilise the coastal hydrosphere. Interrelations of mineral soil - water chemistry prevailed and health hazard predicted would kindle a set of sustainable deliberations. This study summarises the drinking and industrial use of coastal groundwater for future development and human well-being on the basis of quality criteria, corrosion proneness, water stability and health risk factors.

Groundwater conceptual pollution model and related human health hazards, the main dilemma of a desert aquifer near ophiolite complex

Groundwater is a finite resource in Davarzan region which is located between the ophiolite complex mountain in the north and salty playa at the south. The water samples were analyzed to assess the origin of groundwater pollution and explain links between the disturbed heavy metals composition of the earth's surface and the human health risks. The main heavy metal pollutants in the groundwater are Cr, Fe, As and Pb ions. In general, the groundwater salinity and some elements such as Cr and As are increased along with surface topography and groundwater flow directions from the northern ophiolite highlands recharge area to the adjacent desert discharging zone in the south. Despite the ophiolite complexes being the most enriched in Cr element, the lowest Cr concentration in the groundwater was measured near the ophiolite area, which is in the range of its discharged springs. Based on the groundwater conceptual pollution model, bedrock geochemistry controls the composition of soil and hence that of groundwater. The Cr samples show a direct relation with the EC value indicating that intrusion of salinity from the salt pan is probably another reason for the increased Cr concentration. The results of health risk assessment indicated that the groundwater suffered from significant contamination and if used for long-term without pre-treatment may pose serious health risks to human population via drinking water and irrigation of agricultural fields. This is the first attempt to apply hydrogeological setting along with the source of pollution and its health risk in a desert-ophiolitic area.

Machine learning approach for assessment of arsenic levels using physicochemical properties of water, soil, elevation, and land cover

Groundwater is an essential resource; around 2.5 billion people depend on it for drinking and irrigation. Groundwater arsenic contamination is due to natural and anthropogenic sources. The World Health Organization (WHO) has proposed a guideline value for arsenic concentration in groundwater samples of 10[Formula: see text]g/L. Continuous consumption of arsenic-contaminated water causes various carcinogenic and non-carcinogenic health risks. In this paper, we introduce a geospatial-based machine learning method for classifying arsenic concentration levels as high (1) or low (0) using physicochemical properties of water, soil type, land use land cover, digital elevation, subsoil sand, silt, clay, and organic content of the region. The groundwater samples were collected from multiple sites along the river Ganga's banks of Varanasi district in Uttar Pradesh, India. The dataset was subjected to descriptive statistics and spatial analysis for all parameters. This study assesses the various contributing parameters responsible for the occurrence of arsenic in the study area based on the Pearson correlation feature selection method. The performance of machine learning models, i.e., Extreme Gradient Boosting (XGBoost), Gradient Boosting Machine (GBM), Decision Tree, Random Forest, Naïve Bayes, and Deep Neural Network (DNN), were compared to validate the parameters responsible for the dissolution of arsenic in groundwater aquifers. Among all the models, the DNN algorithm outclasses other classifiers as it has a high accuracy of 92.30%, a sensitivity of 100%, and a specificity of 75%. Policymakers can utilize the accuracy of the DNN model to approximate individuals prone to arsenic poisoning and formulate mitigation strategies based on spatial maps.

Occurrence, sources, and spatial distribution of fluoride in the Ganga alluvial aquifer, India

Groundwater contamination throughout India is a global concern as it feeds more than a billion people. Of all the contaminants, fluoride (F) is one of the most widespread and well documented since its toxic nature pose serious threats to human health. In India, groundwater F concentrations have been extensively studied over the past decades. These studies have generally concluded that the groundwater F concentrations are typically higher than the drinking water standard for human health. Here, we present the occurrence, distribution, and sources of groundwater F in the Kanpur Nagar and Kanpur Dehat districts covering ~ 6000 km² of the area in the central part of the Ganga Basin. The result revealed significant spatial variability in dissolved F concentration ranging between 0.2 and 5.2 mg/L (average 0.9 ± 0.7 mg/L, n = 172, 1 SD), which is beyond the drinking water guideline (0.5-1.5 mg/L) of the Indian Standards. We find that 31% of groundwater sampled have F content below the optimal requirement of 0.5-1.0 mg/L causing dental caries problems. The F levels only exceeded the safe drinking water limit of 1.5 mg/L in 8% of the groundwater sampled mostly in the urban regions. Fluoride distribution shows a closer resemblance with the spatial distribution pattern of electrical conductivity, and total dissolved solids demonstrate that F in the shallow alluvial aquifers is largely derived from geogenic sources. This is further confirmed by a strong positive correlation (r = 0.91, p < 0.05) observed between chloride-normalized concentration of F and the sum of geogenic elements (∑Li, Rb, Sr, Ba). We additionally performed health risk assessments, which revealed that children are most vulnerable to dental caries (commonly known as tooth decay) and dental fluorosis problems. As F concentrations show large spatial variability in the studied aquifer, we suggest that uniform application of a single de-fluoridation and fluoridation technology on an aquifer or sub-aquifer scale without a detailed well-designed groundwater F survey will have an adverse health impact on local residents as optimal level of F in drinking water may not be compromised.

Evaluation of groundwater for drinking and irrigation applications concerning physicochemical and ionic parameters through multiple indexing approach: a case study around the industrial zone, Punjab, India

The seasonal quality of groundwater and its appropriateness for drinking and irrigation were assessed using a multiple indexing approach in this study. Physicochemical and ionic parameters were examined in groundwater samples near the industrial zone of Rupnagar, Punjab. To assess groundwater quality, water quality index (WQI) and pollution index were used. The Durov's, piper, wilcox and stiff diagrams were plotted to understand the hydro-chemistry. Similarly, the irrigation indices, i.e., salinity hazard, sodium adsorption ratio, soluble sodium percentage (Na%), magnesium adsorption ratio, residual sodium carbonate, permeability index and Kelley's ratio were applied to ascertain the water quality for agricultural purposes. As a result, total hardness, calcium (Ca²⁺), magnesium (Mg²⁺) and fluoride (F^-) were found above the standard permissible limits. WQI analysis showed 12% samples of pre-monsoon (PRE-M) and 28% samples of post-monsoon (POS-M) were of poor quality, which may pose health risks. Hydrochemistry revealed the predominance of Ca²⁺, Na⁺, Mg²⁺ and HCO₃^- ions in the groundwater attributed to natural and anthropogenic sources. Piper diagram revealed Ca²⁺-Mg²⁺-Cl^-, Na⁺-Cl^-, Ca²⁺-Na⁺- HCO₃^-, Ca²⁺- HCO₃^- and Ca²⁺-Cl, Ca²⁺-HCO₃^- water types exist in the study area. USSL diagram showed that the samples from both seasons come under the low salinity hazard. In addition, total dissolved solids and electrical conductivity showed a strong positive association, indicating the saline nature of groundwater. Furthermore, hierarchical clustering classified groundwater into three groups (I, II and III), revealing that groundwater quality varies due to natural and anthropogenic effects. Based on the findings, the groundwater was found marginally suitable for drinking and irrigation purposes. It is therefore recommended that the groundwater is examined on a regular basis in order to maintain its quality.

A systematic study on occurrence, risk estimation and health implications of heavy metals in potable water from different sources of Garhwal Himalaya, India

The occurrence of heavy metals (HMs) in drinking water has been a critical water quality concern for a long time and can compromise its aesthetic value to the larger extent. Chronic exposure of human beings to these toxic and non-toxic HMs through water ingestion can result in significant health risks. To assess these associated health risks, the present study was planned, designed and carried out for analyses of nine HMs namely, Al, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb in the potable water samples collected from different sources located across the Mandakini valley of Garhwal Himalaya, India using Inductively Coupled Plasma Mass Spectrometry. The measured values of Al, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb were found in the range of BDL-27.4 µg l^-1, 0.26-4.5 µg l^-1, BDL-139 µg l^-1, 0.02-0.9 µg l^-1, 0.4-5.5 µg l^-1, 0.07-9.2 µg l^-1, BDL-4164 µg l^-1, BDL-0.8 µg l^-1, and BDL-11.2 µg l^-1, respectively. The observed values of analyzed HMs except Zn and Pb were found below the reference values prescribed by the WHO, USEPA and BIS. In addition, Zn concentration exceeded its maximum permissible limit (4000 µg l^-1) recommended by WHO for infants at one station only. The observed indices show that there are no health risks from HMs contamination via drinking water in the region. Moreover, the estimated hazard quotients for children and adults also revealed no potential health risks. The results of present study will be useful as baseline data for state and national regulatory agencies.

Combining stable isotope and WQI methods to study the groundwater quality: a case study in Essaouira city, Morocco

Groundwater is an important water resource in arid and semi-arid regions. Therefore, this study aimed to assess groundwater's suitability for drinking and irrigation using the Water Quality Index (WQI) and the Irrigation Water Quality Index (IWQI). To this end, groundwater data were collected from 58 sites in 2019 (wet season) and 61 samples in 2020 (dry season) in the Meskala-Ouazzi sub-basin. The Piper diagram showed that Ca–Mg–Cl was the dominant groundwater facies type. The confinement due to COVID-19 has significantly improved the water quality of the Meskala-Ouazzi sub-basin. Instead, approximately 50% of sites showed improved water quality when calculating the WQI and IWQI. However, the sodium adsorption ratio (SAR) showed that most samples below 10 are found in all of the examined samples, which are mostly found, indicating excellent irrigation water, and the Wilcox diagram depicted 20.14% of samples lying in the unsuitable region. Stable isotopes (δ¹⁸O and δ²H) of groundwater reveal that local precipitation is the main source of recharge. However, groundwater recharge is affected by the evaporation process due to the different geological conditions caused by topographic differences in the study area. The present study is useful for proper planning and managing water resources available for consumption and irrigation.

Water quality has improved during lockdown due to COVID-19.

Assessment of water drinking and irrigation by two models (WQI, and IWQI) in a semi-arid environment.

The main source of groundwater recharge in coastal aquifers is rainfall, based on a stable isotope (δ²H, δ¹⁸O).

Water quality of springs and lakes in the Kumaon Lesser Himalayan Region of Uttarakhand, India

The scarcity of drinking water has become a bitter reality in many countries. The gap between demand and supply of water has been increasing exponentially year by year. Deforestation, vigorous use of groundwater for agricultural practices, and pollution of our present water resources such as rivers, lakes, and wells are triggering the freshwater scarcity problem. Ninety percent of people in Uttarakhand depend on springs for their daily life activities. In such a case, the quality and quantity of spring water should be a prime topic to be focussed on. In the Kumaon region of Uttarakhand, spring water quality is good but there is an issue with its availability, especially in summer. This review paper details the studies that have been conducted on nutrient status, hardness, heavy metals, and the presence of microbiological diversity in spring water. It also uncovers information on some critical springs, geological settings of their aquifers, and the steps that have been adopted to rejuvenate the spring. Some other measures have been carried out by the government and local communities for springs' revival and their improvement in discharge rate, including the construction of percolation pits, contour trenches, check dams, and improvement of water resources. It has been observed among the analyzed sample that the Kumaon region is dominated by arsenic, cadmium, chromium, and lead, whereas aluminum, barium, cobalt, and manganese are more in the Garhwal region. Apart from springs, this review paper also reveals the physicochemical characteristics of the spring-fed rivers and lakes of the Kumaon region.

Spatial and physicochemical assessment of groundwater quality in the urban coastal region of Sri Lanka

Rising sea levels, groundwater exploitation, and urbanization were the primary causes of seawater intrusion, exerting pressure on coastal aquifers. In Sri Lanka's urban coastal region, a comprehensive physicochemical description of groundwater has yet to be identified. Therefore, the objectives of this research were to (a) use a Geographic Information System (GIS) to designate spatial distribution of various water physicochemical characteristics, (b) detect "suitable" groundwater zones for drinking, and (c) estimate groundwater quality by developing a groundwater quality index (GWQI) in Sri Lanka's urban coastal region. The physiochemical parameters of 18 groundwater samples [pH, electrical conductivity (EC), turbidity, total dissolved solids (TDS), Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^-, and HCO₃^-] were studied in terms of their spatial and temporal variation. According to the World Health Organization (WHO) and Sri Lankan Standard Institution (SLS), EC levels in 11% of samples were above the acceptable range, while turbidity levels in 22% of samples were above the acceptable range. Water was consumable in 77.78% of the locations and unsatisfactory in 22.22%. The main hydrochemical facies detected in groundwater samples were Na⁺- Cl^- and the mixed Ca²⁺- Mg²⁺- Cl^- face, which indicated carbonate dissolution and weathering of silicate minerals and the main mechanism controlling the water chemistry in the study area is water-rock interaction. Based on daily water consumption, it was discovered that the HQ is greater than one, in 61% of males, 78% of females, and 89% of children, indicating a health hazard. Furthermore, groundwater quality in the study region is deteriorating due to significant coastal erosion, making it critical to maintain a comprehensive groundwater management strategy to promote sustainable water consumption.

Potable water quality assessment of traditionally used springs in a hilly town of Bhaderwah, Jammu and Kashmir, India

The quality of spring water and its suitability for human consumption is determined by examining its physicochemical and microbiological characteristics. Preliminary investigations were conducted to determine the potability of seven traditionally used springs in the highly populated hill town of Bhaderwah in Union Territory of Jammu and Kashmir, India. The water analysis was performed for various physico-chemical and microbial parameters during April 2019-March 2020. Water temperature, TDS, EC, pH, DO, free CO₂, total alkalinity, total hardness, Ca²⁺, Mg²⁺, Na⁺, K⁺, CO₃^2-, HCOֿ₃, Cl‾, NOֿ_3, PO₄^3-, SO₄^2-, total coliforms, and thermotolerant coliforms were all measured. Eleven physical and chemical characteristics were used to generate the Water Quality Index. The Piper diagram demonstrated the predominance of Ca²⁺-HCOֿ₃ water types, whereas the Schoeller diagram indicated that all springs had a similar lithological origin. The chemical composition of springs tested met the required criteria for drinking water quality. The microbiological indicators, on the other hand, did not satisfy the criteria except for Eidgah spring, which lacked thermotolerant coliforms. Our results on spring water potability indicate that the town's most dependable springs are susceptible to anthropogenic contamination and therefore need treatment prior to use. Apart from frequent monitoring, the responsible municipal corporation is expected to develop comprehensive plans to rehabilitate and revitalise these vulnerable drinking water sources.

Risk assessment and water safety planning for rural water supply in Uttarakhand, India

A water safety plan (WSP) has been developed for rural water supply in Dehradun district, Uttarakhand, India. Four public water utilities were chosen to demonstrate the application of WSP in improving the rural drinking water quality along with improved sanitation. Hazard identification and risk assessment carried out identified 10 hazardous events at all four utilities. Intermittent water supply, poor repair and maintenance of the supply channel machinery, and individual household sanitation practices were the potential sources of contamination. The study showed encouraging results, where the evaluated risks decreased substantially after implementing the control measures, along with improved water quality after WSP implementation which showed statistically significant results (p < .05) for all tested parameters, namely, turbidity (p = .000), total dissolved solids (p = .004), residual-free chlorine (p = .004), total coliforms (p = .000), and fecal coliforms (p  = .003). The sanitation condition of water source and households also improved by adopting the suggested measures. The study recommends water safety planning, to empower the rural communities to safeguard their water sources, and for sustainable water supply management.

Conceptual Model for the Vulnerability Assessment of Springs in the Indian Himalayas

The Indian Himalayan Region is home to nearly 50 million people, more than 50% of whom are dependent on springs for their sustenance. Sustainable management of the nearly 3 million springs in the region requires a framework to identify the springs most vulnerable to change agents which can be biophysical or socio-economic, internal or external. In this study, we conceptualize vulnerability in the Indian Himalayan springs. By way of a systematic review of the published literature and synthesis of research findings, a scheme of identifying and quantifying these change agents (stressors) is presented. The stressors are then causally linked to the characteristics of the springs using indicators, and the resulting impact and responses are discussed. These components, viz., stressors, state, impact, and response, and the linkages are used in the conceptual framework to assess the vulnerability of springs. A case study adopting the proposed conceptual model is discussed for Mathamali spring in the Western Himalayas. The conceptual model encourages quantification of stressors and promotes a convergence to an evidence-based decision support system for the management of springs and the dependent ecosystems from the threat due to human development and climate change.

An assessment of groundwater quality in Zimbabwe's urban areas: case of Mkoba 19 suburb, Gweru

Groundwater quality assessment in urban areas is one of significant endeavours to ensure safety of urban residents who use groundwater especially in areas with erratic tap water supply. The study assessed groundwater quality and vulnerability of residents to water contamination-related diseases in Mkoba 19 suburb in Gweru, Zimbabwe. The research employed a mixed methods research design using both quantitative and qualitative research methods. Laboratory tests, questionnaires, interviews, focus group discussions and observations were used to solicit data. Statistical package for social scientist (SPSS) version 20.0 and Microsoft excel package were adopted for data analysis in this study. The study revealed that Mkoba 19 suburb has more wells than boreholes. Boreholes were evenly distributed over the residential area than wells which were clustered to the southern and northern edges of the suburb. All boreholes in Mkoba 19 were drilled to the depth of 40 m, but wells were dug to varying depths. The study confirmed that borehole water in Mkoba 19 was acidic and thus unsafe for human consumption. Water from wells in Mkoba 19 was confirmed positive of Escherichia coli which shows contamination from sewage and waste dump leachates. The findings of this research indicated that both borehole and well water sources in Mkoba suburb had permissible levels of dissolved oxygen and turbidity. Chi-square tests conducted confirmed that there was an association between water source depth and level of E. coli contamination in water whereas there is no association between water source depth and water pH level. The research confirmed that residents of Mkoba 19 were highly vulnerable to water borne illnesses as they were using contaminated water for domestic purposes without treating it. Basing on similar studies conducted in the past 3 years, it was shown that groundwater quality in Mkoba 19 mimics that of other countries of the developing world, especially in sub-Saharan Africa, which shows that vulnerability to ground water contamination in urban areas is an issue that requires critical attention and almost similar solution. The research recommends that Gweru City Council should upgrade its water supply system especially the pumping system to improve water supply in Mkoba suburb. To minimize water-borne disease outbreaks in the future, urban residents who rely on secondary or tertiary sources of water for domestic purposes should treat water using chlorine, water guards and other water cleansing measures on a regular basis.

Hydro chemical Assessment of Ground Water in North-Eastern Region of India: A Case Study of Western Suburb of Jorhat Town of Assam, India

In the current study, the quality of ground water (GW) from an area of western part of Jorhat district of Assam (India) was assessed in order to ensure the safety of its use in irrigation and drinking purposes. The physico-chemical parameters of the collected GW samples were evaluated and compared the data with the Indian Standards (IS) for drinking purposes. The investigation was mainly emphasised on the evaluation of Water Quality Index (WQI) and different parameters for the quality measurement of water for drinking and irrigation purposes, respectively. Correlations among the physico-chemical parameters were evaluated through statistical analysis. The physico-chemical parameters revealed that almost all the parameters except iron were within the permissible limit. Arsenic was found to be present in few water samples in both seasons (pre and post monsoon). In both the seasons, the WQI of the majority of collected water samples were observed to be falling under the poor category for drinking. Almost all the collected water samples were found to be fit for irrigation purposes. However, based on sodium percentage (Na %), Kelly’s ratio (KR), and Magnesium ratio (MR), few of the water samples are classified to be doubtful and inappropriate for irrigation.

Solute exchanges between multi-depth groundwater and surface water of climatically vulnerable Gangetic delta front aquifers of Sundarbans

The coastal aquifers of Sundarbans, an UNESCO world biodiversity heritage site, are highly vulnerable due to changing climatic conditions, intensification and increasing frequency of extreme climate events and uncontrolled abstraction of groundwater. The exchange of solutes between hydraulically connective shallow and deep aquifers, the seawater intrusion and the role of growing population are poorly understood in the Sundarbans. This study aims to address the solute exchange (Cl^-, Sr²⁺, and salinity) process between surface water and groundwater (SW-GW) at local to regional scale under variable hydraulic head conditions, where annual rainfall is declining and population density is increasing [population 573 (1991) to 819 (2011)/Km²]. Electrical resistivity tomography (ERT) in combination with salinity and δ¹⁸O data was used to address the exchange of solutes between SW-GW in a hydraulic continuation. The results revealed that regionally, the Cl^- concentration of Sundarbans shows an increasing trend (average 329-351 mg/L) with declining groundwater levels (⁓3 m). Local, depth-dependent study depicting there is a predominant exchange of Sr²⁺ between shallow depth [D1: 14-25 and D2: 30-50 m below ground level (m bgl)] with seawater (Sr²⁺: 30-85 μM), which is possibly absent at greater depths (D3:115 and D4: 333 m bgl). The recorded Sr²⁺ content ranged from 25 to 102 and 16 to 78 μM for shallow depth D1 and D2, respectively, whereas, the Sr²⁺ concentrations ranged from 1.4 to 6.8 and 1.2 to 5.7 μM for D3 and D4, respectively. The ERT data showed progressively increasing resistivity with increasing depth, similar to high salinity and enriched δ¹⁸O at shallow depths and depleted δ¹⁸O with low salinity at higher depth reflects the continuous distribution of solutes, which is possibly a result of local downward migration of contaminated shallow brackish water within this physically disconnected zone. The lateral and vertical transportation of solutes in variable hydraulic head conditions would be a measure of drinking water threat in present-day and in imminent future for millions of inhabitants near the coastal area.

Impact of hydrogeochemical processes and its evolution in controlling groundwater chemistry along the east coast of Tamil Nadu and Puducherry, India

The present study area falls beside the coastal zone of Tamil Nadu, and Puducherry is characterized by varied geological formations that mostly contain groundwater resources that are primarily utilized for domestic, agricultural, industrial, and other utilities. The study aims to differentiate various hydrogeochemical processes responsible for disparities in water chemistry. Groundwater samples were collected from 66 sites during the two major seasons: pre-monsoon and post-monsoon. The analytical data were separated into terrain vice and utilized for preparing graphical plots as well as mathematical calculations to obtain the existing relationship among chemical constituents and water quality. The Ca-HCO3, Na-Cl, Ca-Na-HCO3, mixed Ca-Mg-Cl, Ca-Cl, and Na-HCO₃ are the main hydrochemical facies observed from the groundwater samples. The ionic relationship among the samples indicates the control of direct and reverse ion exchange in the concentration of Ca²⁺, Mg²⁺, Na⁺, and K⁺ in groundwater. Moreover, silicate weathering contributes more in comparison with carbonate and evaporite dissolution. Gibbs plots reveal that water-rock interaction and evaporation processes are the main mechanisms controlling the water chemistry. The saturation index of different mineral phases indicates groundwater to be oversaturated with silicate mineral phases irrespective of the terrain. Statistical methods like correlation and principal component analysis were also performed to differentiate the specific association and possible source of the dissolved constituent in the groundwater. The study concludes the influence of multiple processes such as silicate weathering, direct and reverse ion exchange, secondary dissolution, saline water intrusion, and anthropogenic sources as the main reasons responsible for variation in groundwater chemistry.

Ratiometric determination of Cr(VI) based on a dual-emission fluorescent nanoprobe using carbon quantum dots and a smartphone app

A simple dual-colour fluorescent nanoprobe has been designed composed of blue and yellow emission carbon quantum dots (CQDs). This system is inexpensive and easy to operate and was successfully employed for on-site measurements based on a smartphone app. The designed nanoprobe exhibited increased selectivity for Cr(VI), leading to a double stable response of the two CQDs. The dual-emission nanoprobe showed blue-violet fluorescence upon UV irradiation, and the fluorescent emission peaks were located at 418 nm and 552 nm. The blue light emission of CQDs was quenched with increasing Cr(VI) concentration due to the inner filter effect, whereas the yellow light emission was enhanced due to the aggregation-induced emission effect. The different responses of the dual emissions to Cr(VI) resulted in a fluorescent colour variation, thus enabling facile macroscopic visualization. With a smartphone, the change in the fluorescence colour could be observed more apparently than that of a single fluorescence nanoprobe, and the response increased linearly so that the nanoprobe could be applied to instantaneous measurements. Furthermore, the dual-emission nanoprobe was successfully employed for analysing food and water samples. Accurate concentrations were obtained by constructing a calibration plot using a fluorescence spectrometer and a smartphone app; the recoveries were 81.6% to 107.7%, and the relative standard deviation was below 3.6%. Therefore, this smartphone-integrated dual-emission detection system is promising as a new portable method for the on-site measurement of Cr(VI) ions. * Y-CQDs: yellow emission carbon quantum dots. B-CQDs: blue emission carbon quantum dots. B/Y-CQDs: a mixture of B-CQDs and Y-CQDs.

The combined exposure of microplastics and toxic contaminants in the floodplains of north India: A review

Microplastics in aquatic ecosystem are an emerging environmental threat, primarily aggregating into sediments and living biota besides providing active transportation to toxic pollutants. Recent studies have revealed that a microplastic surface cannot be considered as "inert" and therefore the rate and stage of degradation of microplastic will determine its capability in adsorbing and transporting the solute to longer distances. Our concern is driven by the fact that there has been an absence of widescale research in India despite a country with one of the longest networks of rivers and a 7500 km long active coastline. Anthropogenic pollutants are expected to increase and the situation will further worsen when more persistent organic pollutants (POCs) and geogenic contaminants will find its sink via monsoon runoff. Studies on aquatic species including COD, daphnia magna and zebrafish suggest strong links of bio-accumulation, suspecting to a more serious situation for the coastal India where there is an almost three times increase in the density of the microplastics as the monsoon progresses. Evidences also suggests that microplastics can adsorb known carcinogens as well as endocrine disrupting chemicals leaving our aquatic life exposed to higher mortality. Our review is a first ever scientific attempt in compiling these evidences through researches done in this field to understand the risk that the major floodplains of North India are currently facing. We have adapted the theories and inferences of the available research to predict and postulate a probable mechanism that could explain the severity of the situation in India.

Estimation of uranium in groundwater and assessment of age-dependent radiation dose in Nalbari district of Assam, India

Uranium concentration has been estimated in 31 groundwater samples collected from the Nalbari district of Assam in pre-monsoon and post-monsoon season. Fourteen other water quality parameters have also been monitored to study their correlation with uranium. The uranium concentration varies from 0.3 to 7.1 µg/L with the mean value of 2.15 µg/L in pre-monsoon and 0.6–10.3 µg/L with the mean value of 2.75 µg/L in the post-monsoon season. The higher concentration of uranium in post-monsoon may be ascribed to the dissolution of uranium from soil sediments in the rainy season. It has been observed that the uranium content in both seasons is far lower than the WHO (2011) permissible limit of 30 µg/L. In both seasons, nitrate, sulphate, and especially phosphate show a positive correlation with uranium, which may be due to different agricultural activities. Agricultural nitrate and phosphate fertilization might be the carrier of uranium in groundwater through dissolution. For all life stage groups, the annual effective dose was appeared to be far below the WHO (2011) prescribed limit of 100 µSv/y. In consideration to adults, the ingestion dose for infants was turned out to be higher. The carcinogenic and non-carcinogenic risk was less than the permissible limits for both children and adults. Both dose value and risk indices were found higher in the post-monsoon season.

Water quality index and GIS-based technique for assessment of groundwater quality in Wanaparthy watershed, Telangana, India

A comprehensive study of 58 groundwater samples collected in the virgin area of Wanaparthy watershed (1600 km²), Telangana, India, to assess the hydrochemistry, quality, water types and potability using hydrogeochemical characterization, WQI and GIS technique. Major ions concentration of Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^-, F^-, NO₃^- and SO₄^2- in groundwater were analysed using ion chromatography (IC). Physicochemical values of the potential of hydrogen (pH), total dissolved solids (TDS) and electrical conductivity (EC) were determined using Hanna portable meters, while total hardness (TH), alkalinity and bicarbonates are estimated by titrimetric methods. Results obtained enlighten the major anions and cations, which are found in order of Cl^- > HCO₃^- > SO₄^2- > NO₃^- > F^- and Na⁺ > Ca⁺² > Mg⁺² > K⁺ respectively. Among various ions measured, fluoride (18.97%), chloride (3.44%), nitrate (8.62%), sulphate (5.17%), sodium (34.48%) and calcium (1.72%) were found to above acceptable limit values of Bureau of Indian Standards (BIS) for drinking purposes. According to Piper trilinear diagram, two dominant hydrochemical facies, Na-Cl-SO₄ and Ca-Na-HCO₃ types, were identified. Gibbs diagram imparted the dominancy of samples in the territory are rock-water reaction and evaporation dominance. WQI shows 67.79% of samples pertain to the excellent to good water types reveal fit for drinking. Drainage pattern enumerated the concentration of the parameters measured are exceeding towards the downstream region, which might be due to the chemical reaction of rock-water interaction (infiltration and recharge). As the groundwater is the major source of drinking in the study area, a proper management plan has to implement before its quality deteriorated.

Monitoring of pre- and post-monsoon groundwater quality of north-eastern Haryana region using GIS

The present paper is the result of an investigation carried out to analyse the quality of sub-surface water in the districts of Yamunanagar and Ambala of the province of Haryana in India. The investigation was necessitated as the area combines the presence of industrial, commercial and residential units close to each other. A total of 30 groundwater samples were taken each during the months of April and September of 2017 and were appraised for analytical parameters, hydro-geochemical constituents and metal ions. Eight locations were observed to have an abnormal presence of only one element and were, therefore, classified to be falling in the 'Grey-Zone'. Matedi Bus Stand (Sample number - 23) was found to be adversely influenced by the presence of the most of chemical elements and thus was categorized as the 'Red Zone'. For the combined data of post-monsoon and pre-monsoon periods of 2017, the spatial distribution of pH, TDS, TA and TH showed that 100%, 90%, 91.67% and 93.33% of samples, respectively, fall under allowable limits of groundwater quality. Spatial distribution of hydro-chemical elements and metal ions showed that 96.11% of samples for cations, 98.33% for anions and 93.33% for Fe are in the 'allowable' category of groundwater. A comparison of laboratory results with the GIS maps prepared during the study has been found to be in good agreement. The classification of samples pursuance to their hydro-chemical facies indicated that most of the samples fall in Ca²⁺-Mg²⁺- H C O 3 - -Cl^- and Na⁺- H C O 3 - -Cl^- type.

Monte Carlo simulation-based probabilistic health risk assessment of metals in groundwater via ingestion pathway in the mining areas of Singhbhum copper belt, India

Probabilistic health risk assessment was conducted for metal exposure through groundwater in mining areas of Singhbhum Copper Belt, India. The concentrations of metals showed notable spatial variation exceeding drinking water standards at some of the locations. Hazard Quotient revealed that chronic risks to the local population were largely contributed by Mn, Co and As. The 95^th percentiles of Hazard Index (HI) calculated using Monte Carlo simulations showed that the HI for male, female and child populations was 2.87, 2.54 and 4.57 for pre-monsoon, 2.16, 1.88 and 3.49 for monsoon and 2.28, 2.02 and 3.75 for post-monsoon seasons, respectively. The Hazard Indices indicated that amongst the populations, risk was greater for child population and considering the seasons the risk was higher during the pre-monsoon season. The sensitivity analysis suggested that concentration of metals in groundwater and exposure duration were 2 most influential input variables that contributed to the total risk.

The impact of anthropogenic organic and inorganic pollutants on the Hasdeo River Water Quality in Korba Region, Chhattisgarh, India

In the name of development, industries discharge their wastewater, which contains different Metallic species and massive organic load into the next-door river system. In this study, we assess the impact of organic and inorganic contaminations on Hasdeo River at Korba region, which is fifth critically polluted city in India. Hear, a new approach for water quality indexing like Water quality index (WQI), Heavy metal pollution index (HPI) and metal index (MI) has been proposed to represent pollution due to heavy metals in river system. The sample's pollution parameters and heavy metals contamination is exceed from BIS or WHO standards of drinking water (all p<0.05). WQI shows that the entire water samples are not suitable for drinking and aquatic life but they are safe only for irrigation. HPI and MI calculation revels that more than 95% sampling sites are critically polluted with heavy metals. Thus, a high level of industrialization deterioration of river water quality is recorded for adequate action.

Evaluation of groundwater contamination in Chandigarh: Source identification and health risk assessment

The major objective of the current study is to estimate the groundwater quality and identify the likely sources of contamination in Chandigarh, India. Total 80 groundwater samples were collected from different locations and at various depths. Further, physcio-chemical analysis was done to estimate pH, electrical conductivity (EC), total dissolved solids, total hardness (TH), total alkalinity (TA), Na⁺, K⁺, Cl^-, SO₄^2-, PO₄^3- and NO₃^-. The groundwater samples collected from shallow water sources contain higher concentration of total dissolved salts. EC, TA, Cl^-, TH, Na⁺, and K⁺ were found relatively higher in the shallow aquifer (<150 ft). Based on the location of pollution sources at the surface and consecutive geo-statistical distribution of physicochemical characteristics, this study suggests that non-scientific disposal of municipal solid waste, dumping of industrial waste and agricultural activities, in the nearby areas lead to the deterioration of groundwater of shallow aquifer. These observations were also confirmed using various water quality indices and outcomes of multivariate modeling, including principal component analysis. Health risk assessment for nitrates indicated that 29 groundwater samples pose non-carcinogenic health risk for children due to dermal and oral exposure. Hence, there is a need to establish a system for regularly assessing the groundwater quality to minimize public health risks.

Distribution and health risk assessment of arsenic and selected heavy metals in Groundwater of Chandigarh, India

Groundwater quality of Chandigarh was assessed by collecting 80 groundwater samples from different depths varying between 10 ft and 1200 ft. These samples were analyzed for possible contamination with metal pollutants such as Al, Cd, Co, Cr, Cu, Fe, Mo, Mg, Ni, Pb, V, Zn. Geospatial interpolation of the contaminants identified poor sanitary practices of waste management, agrarian activities, and industrial pollution as the prominent sources of groundwater contamination. Quality assessment of groundwater performed using Heavy metal Pollution Index (HPI), and Metal Index (MI) revealed HPI as a better method for health risk assessment. HPI indicate poor groundwater quality near municipal solid waste dumping sites and industrial areas of Chandigarh. The shallow aquifer was reported to be more contaminated than deeper aquifer. Further, health risk assessment of Chandigarh's groundwater indicated non-carcinogenic health impacts due to contamination of As, Cr, Co, Cd, Cu, Ni, Pb, Zn and carcinogenic health impacts from As, Cd, Cr, Cu, Pb. The study suggests that groundwater should also be regularly monitored for metal contamination as over-extraction, industrialization, disposal of municipal solid waste and informal E-waste recycling activities increases the public health risks in countries worldwide, facing similar environmental pollution problems of the groundwater.

Uranium distribution in groundwater and assessment of age dependent radiation dose in Amritsar, Gurdaspur and Pathankot districts of Punjab, India

A comprehensive study of seasonal variation of uranium distribution in groundwater of Amritsar, Gurdaspur and Pathankot districts of Punjab, India and assessment of associated radiological risks, chemical risks and effective radiation dose for different age groups, was conducted to determine its health impact on humans residing in these regions. Physicochemical parameters such as pH, EC, TDS, total hardness and contents of various anions such as carbonates/bicarbonates, chlorides, fluorides, nitrates, sulphates and phosphates in groundwater were also analysed to determine correlation between groundwater chemistry and uranium distribution. The average values of uranium concentration in ground water samples of Amritsar, Gurdaspur and Pathankot districts were found to be 8.6 μg L^-1, 4.3 μg L^-1 and 3.0 μg L^-1, respectively, in pre-monsoon and 8.8 μg L^-1, 4.9 μg L^-1 and 3.4 μg L^-1, respectively, in post-monsoon. The uranium concentration in majority of the ground water samples was found to be below the permissible limit of 30 μg L^-1 recommended by World Health Organization (WHO, 2011). In all three districts, TDS, EC and bicarbonates were found to have positive correlation with observed uranium contents in both seasons. The annual effective dose due to ingestion of uranium through drinking water was found to be less than the prescribed limit of 100 μSv y^-1 given by WHO (2004). Radiological and chemical toxicity risk assessment of uranium in groundwater was also carried out and found to be within the permissible values of 1.67 × 10^-4 and 4.53 μg kg^-1 day^-1 respectively, recommended by Atomic Energy Regulatory Board (AERB, 2004).

Groundwater fluoride contamination, probable release, and containment mechanisms: a review on Indian context

Fluoride contamination in the groundwater has got great attention in last few decades due to their toxicity, persistent capacity and accumulation in human bodies. There are several sources of fluoride in the environment and different pathways to enter in the drinking water resources, which is responsible for potential effect on human health. Presence of high concentration of fluoride ion in groundwater is a major issue and it makes the water unsuitable for drinking purpose. Availability of fluoride in groundwater indicates various geochemical processes and subsurface contamination of a particular area. Fluoride-bearing aquifers, geological factors, rate of weathering, ion-exchange reaction, residence time and leaching of subsurface contaminants are major responsible factors for availability of fluoride in groundwater. In India, several studies have reported that the groundwater of several states are contaminated with high fluoride. The undesirable level of fluoride in groundwater is one of the most natural groundwater quality problem, which affects large portion of arid and semiarid regions of India. Rajasthan, Andhra Pradesh, Telangana, Tamil Nadu, Gujarat, and West Bengal are the relatively high-fluoride-contaminated states in India. Chronic ingestion of high doses of fluoride-rich water leads to fluorosis on human and animal. Over 66 million Indian populations are at risk due to excess fluoride-contaminated water. Therefore, groundwater contamination subject to undesirable level of fluoride needs urgent attention to understand the role of geochemistry, hydrogeology and climatic factors along with anthropogenic inputs in fluoride pollution.

Fluoride distribution and contamination in the water, soil and plants continuum and its remedial technologies, an Indian perspective- a review

Fluorine is an essential element required in trace amounts but gets toxic for human beings at levels more than 1.5 mg F^- L^-1 primarily through drinking contaminated water. It is the 13th most abundant element and constitutes about 0.06-0.09% in the earth crust. It is electronegative in aqueous medium forming fluoride ion (F^-). Fluoride contamination in the environment occurs mostly due to anthropogenic and geogenic sources. Fluoride is widely distributed in all components of environment, air (0.1-0.6 μg L^-1) soils (150-400 mg Kg^-1) rocks (100-2000 mg Kg^-1), plant (0.01-42 mg Kg^-1) and water (1.0-38.5 mg L^-1). Human beings and animals are being exposed to F^- primarily from water (0.2-42.0 mg L^-1) and plants (0.77-29.5 μg g^-1). Fluorosis, a health hazard due to F^- is a major problem in many countries across the world affecting about 200 million people globally. In India, > 62 million people in twenty states are facing problem due to F^-. The most affected states are Rajasthan (7670 habitations), Telangana (1,174 habitations) and Karnataka (1122 habitations). To mitigate this problem, there is an urgent need to understand the current status and brief knowledge of F^- geochemistry. The objective of this review is to highlight different sources of F^- that contaminate different environmental matrices including plants, the extent of contamination level in India, uptake, translocation and toxicity mechanism in plants. The review also highlights currently available mitigation methods or technologies through physio-chemical and biological means.

Fluoride-contaminated groundwater of Birbhum district, West Bengal, India: Interpretation of drinking and irrigation suitability and major geochemical processes using principal component analysis

The present research work is confined to a rural tract located in the north-western part of Birbhum district, West Bengal, India. Chemical analysis of the groundwater shows the cations is in the order of Na⁺ > Ca²⁺ > Mg²⁺ while for anions it is HCO₃^─ > Cl^─ > SO₄^2─ > NO₃^─. The F^─ concentration was found to vary from 0.01 to 18 mg/L in the pre-monsoon and 0.023 to 19 mg/L in post-monsoon period. 86% of samples show low F^─ content (<0.60 mg/L) whereas, 8% exhibit elevated concentration of F^─ (>1.2 mg/L) mainly in the central and north-central parts of the study area at a depth of 46 to 98 m. The prime water type is CaHCO₃ succeeded by F^─-rich NaHCO₃ and NaCl waters. The suitability analysis reveals that the water at about 81% of the sampling sites is unsuitable for drinking and at 16% of sites unsuitable for irrigation. The alkaline nature of the water and/or elevated concentration of Fe, Mn and F^─ make the water unsuitable for potable purposes while the high F^─ and Na⁺ contents delimit the groundwater for irrigation uses. Multivariate statistical analysis suggests that chemical weathering along with ion exchange is the key process, responsible for mobilization of fluoride in groundwater of the study area.

A study of trace element contamination using multivariate statistical techniques and health risk assessment in groundwater of Chhaprola Industrial Area, Gautam Buddha Nagar, Uttar Pradesh, India

This study is an investigation on spatio-chemical, contamination sources (using multivariate statistics), and health risk assessment arising from the consumption of groundwater contaminated with trace and toxic elements in the Chhaprola Industrial Area, Gautam Buddha Nagar, Uttar Pradesh, India. In this study 33 tubewell water samples were analyzed for 28 elements using ICP-OES. Concentration of some trace and toxic elements such as Al, As, B, Cd, Cr, Mn, Pb and U exceeded their corresponding WHO (2011) guidelines and BIS (2012) standards while the other analyzed elements remain below than those values. Background γ and β radiation levels were observed and found to be within their acceptable limits. Multivariate statistics PCA (explains 82.07 cumulative percent for total 6 of factors) and CA indicated (mixed origin) that natural and anthropogenic activities like industrial effluent and agricultural runoff are responsible for the degrading of groundwater quality in the research area. In this study area, an adult consumes 3.0 L (median value) of water therefore consuming 39, 1.94, 1461, 0.14, 11.1, 292.6, 13.6, 23.5 μg of Al, As, B, Cd, Cr, Mn, Pb and U from drinking water per day respectively. The hazard quotient (HQ) value exceeded the safe limit of 1 which for As, B, Al, Cr, Mn, Cd, Pb and U at few locations while hazard index (HI) > 5 was observed in about 30% of the samples which indicated potential health risk from these tubewells for the local population if the groundwater is consumed.

Effectiveness of Membrane Filtration to Improve Drinking Water: A Quasi-Experimental Study from Rural Southern India

Since point-of-use methods of water filtration have shown limited acceptance in Vellore, southern India, this study evaluated the effectiveness of decentralized membrane filtration 1) with safe storage, 2) without safe storage, versus 3) no intervention, consisting of central chlorination as per government guidelines, in improving the microbiological quality of drinking water and preventing childhood diarrhea. Periodic testing of water sources, pre-/postfiltration samples, and household water, and a biweekly follow up of children less than 2 years of age was done for 1 year. The membrane filters achieved a log reduction of 0.86 (0.69–1.06), 1.14 (0.99–1.30), and 0.79 (0.67–0.94) for total coliforms, fecal coliforms, and Escherichia coli, respectively, in field conditions. A 24% (incidence rate ratio, IRR [95% confidence interval, CI] = 0.76 [0.51–1.13]; P = 0.178) reduction in diarrheal incidence in the intervention village with safe storage and a 14% (IRR [95% CI] = 1.14 [0.75–1.77]; P = 0.530) increase in incidence for the intervention village without safe storage versus no intervention village was observed, although not statistically significant. Microbiologically, the membrane filters decreased fecal contamination; however, provision of decentralized membrane-filtered water with or without safe storage was not protective against childhood diarrhea.

Surveillance of bacteriological quality of drinking water in Chandigarh, northern India

The study was carried out in Chandigarh, India with the following objectives: (1) to monitor the bacteriological quality of drinking water; (2) to collect data on bacteriological contamination of water collected at point of use; (3) to test both groundwater being supplied through hand pumps and pre-treated water; and (4) to determine the pattern of seasonal variations in quality of water. The community-based longitudinal study was carried out from 2002 to 2007. Water samples from hand pumps and tap water were collected from different areas of Chandigarh following a simple random sampling strategy. The time trends and seasonal variations in contamination of water according to area and season were analysed. It was found that the contamination of water was higher during the pre-monsoon period compared with the rest of the year. The water being used in slums and rural areas for drinking purposes also had higher contamination levels than urban areas, with highest levels in rural areas. This study found that drinking water supply in Chandigarh is susceptible to contamination especially in rural areas and during pre-monsoon. Active intervention from public health and the health department along with raising people's awareness regarding water hygiene are required for improving the quality of drinking water.

Physico-Chemical and Microbial Analysis of Selected Borehole Water in Mahikeng, South Africa

Groundwater is generally considered a "safe source" of drinking water because it is abstracted with low microbial load with little need for treatment before drinking. However, groundwater resources are commonly vulnerable to pollution, which may degrade their quality. An assessment of microbial and physicochemical qualities of borehole water in the rural environs of Mahikeng town, South Africa, was carried out. The study aimed at determining levels of physicochemical (temperature, pH, turbidity and nitrate) and bacteriological (both faecal and total coliform bacteria) contaminants in drinking water using standard microbiology methods. Furthermore, identities of isolates were determined using the API 20E assay. Results were compared with World Health Organisation (WHO) and Department of Water Affairs (DWAF-SA) water quality drinking standards. All analyses for physicochemical parameters were within acceptable limits except for turbidity while microbial loads during spring were higher than the WHO and DWAF thresholds. The detection of Escherichia coli, Salmonella and Klebsiella species in borehole water that was intended for human consumption suggests that water from these sources may pose severe health risks to consumers and is unsuitable for direct human consumption without treatment. The study recommends mobilisation of onsite treatment interventions to protect the households from further possible consequences of using the water.

Groundwater Quality Assessment in Jazan Region, Saudi Arabia

Jazan province is an arid area, located at the southwestern part of Saudi Arabia along the Red Sea coast. Groundwater is the only resource of drinking water in this area; thus, its suitability for drinking and domestic uses is of public and scientific concern. In this study, groundwater samples were collected from 23 sites in Jazan area during fall 2014; measurements and analysis of water quality parameters including pH, total dissolved solids TDS, turbidity, hardness, alkalinity, ammonia, nitrite, nitrate, sulfate, calcium, magnesium, chloride, iron and fluoride were carried out with references to WHO and Gulf Standardization Organization GSO. TDS values exceeded the permissible limit of 600 mg/l in 30.4% of samples, total hardness values exceeded the permissible limits of 300 mg/l in 34.8% of samples, and nitrate concentration exceeded the permissible limit of 50 mg/l in only one sample. However, the concentrations of investigated parameters in the groundwater samples were within the permissible limits of WHO. Our results showed that the water quality of groundwater in Jazan area is acceptable and could be used safely for drinking and domestic purposes. However, a special attention should be paid to the concentration of TDS and nitrate in groundwater in future studies.

Variation in Groundwater Quality with Seasonal Fluctuation in Jharia Coal Mine Region, Jharkhand, India

Jharia coal mining areas is one of the most important coal mining areas in India. It is roughly elliptical or sickles – shaped, located in Dhanbad district of Jharkhand. For the assessment of groundwater quality, Twenty Nine groundwater samples were collected from Jharia coalfield. The pH of the analysed water samples is slightly acidic to slightly alkaline in nature in both the season. The quality assessment of groundwater shows that in general, the water is suitable for domestic purposes with some exceptions. In majority of the samples, the analyzed parameters are well within the desirable limits and water is potable for drinking purposes. However, concentrations of EC, TDS, TH, SO42-, Na+, Ca2+ and Mg2+exceed the desirable limit at few sites. The water level fluctuation shows in the study area for year 2013 is 1.29 to 6.9 mbgl. West and some part of the northern area are facing extreme scarcity due to lower availability of groundwater resource. However, eastern region of the study area has sufficiently available of groundwater resources in the Jharia coalfield. This study is useful for utilization of groundwater resources in mining area and helps in future water resource planning for the area.

Human health risk assessment via drinking water pathway due to metal contamination in the groundwater of Subarnarekha River Basin, India

Groundwater samples were collected from 30 sampling sites throughout the Subarnarekha River Basin for source apportionment and risk assessment studies. The concentrations of As, Ba, Cd, Cr, Co, Cu, Fe, Mn, Mo, Ni, Se, Sr, V and Zn were determined using inductively coupled plasma-mass spectrometry (ICP-MS). The results demonstrated that concentrations of the metals showed significant spatial variation with some of the metals like As, Mn, Fe, Cu and Se exceeding the drinking water standards at some locations. Principal component analysis (PCA) outcome of four factors that together explained 84.99 % of the variance with >1 initial eigenvalue indicated that both innate and anthropogenic activities are contributing factors as source of metal in groundwater of Subarnarekha River Basin. Risk of metals on human health was then evaluated using hazard quotients (HQ) and cancer risk by ingestion for adult and child, and it was indicated that Mn was the most important pollutant leading to non-carcinogenic concerns. The carcinogenic risk of As for adult and child was within the acceptable cancer risk value of 1 × 10(-4). The largest contributors to chronic risks were Mn, Co and As. Considering the geometric mean concentration of metals, the hazard index (HI) for adult was above unity. Considering all the locations, the HI varied from 0.18 to 11.34 and 0.15 to 9.71 for adult and child, respectively, suggesting that the metals posed hazard by oral intake considering the drinking water pathway.

Trace elements contamination and human health risk assessment in drinking water from Shenzhen, China

The levels of seven essential trace elements (Mn, Co, Ni, Cu, Zn, Se, and Mo) and six non-essential trace elements (Cr, As, Cd, Sb, Hg, and Pb) in a total of 89 drinking water samples collected in Shenzhen, China were determined using inductively coupled plasma mass spectrometry (ICP-MS) in the present study. Both the essential and non-essential trace elements were frequently detectable in the different kinds of drinking waters assessed. Remarkable temporal and spatial variations were observed among most of the trace elements in the tap water collected from two tap water treatment plants. Meanwhile, potential human health risk from these non-essential trace elements in the drinking water for local residents was also assessed. The median values of cancer risks associated with exposure to carcinogenic metals via drinking water consumption were estimated to be 6.1 × 10(-7), 2.1 × 10(-8), and 2.5 × 10(-7) for As, Cd, and Cr, respectively; the median values of incremental lifetime for non-cancer risks were estimated to be 6.1 × 10(-6), 4.4 × 10(-5), and 2.2 × 10(-5) for Hg, Pb, and Sb, respectively. The median value of total incremental lifetime health risk induced by the six non-essential trace elements for the population was 3.5 × 10(-5), indicating that the potential health risks from non-carcinogenic trace elements in drinking water also require some attention. Sensitivity analysis indicates that the most important factor for health risk assessment should be the levels of heavy metal in drinking water.