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Consumption of poor quality water causes serious human health hazards. Therefore, it is very crucial to investigate factors influencing the quality of groundwater and its suitability for drinking purpose. In the present study, groundwater quality of the Dhenkanal district of Odisha, India was characterized and the spatial distribution of different water quality parameters were analyzed using the multivariate statistics, entropy theory, and geostatistics techniques. In the present study 112 number of groundwater tube well samples were collected from the study area. The entropy theory revealed that SO42-, Mg+2 and Cl- were the most influencing parameters. A similar observation was also observed based on the correlation coefficient analysis. Groundwater quality index (GWQI) and entropy-weighted water quality index (EWQI) classifications indicated that 78.57 and 43.75% of the collected groundwater samples were categorized under excellent water quality, whereas, the rest of the samples were varying from good to medium drinking water quality. In addition, the result of EWQI classification offers more realistic assessment than that of GWQIs owing to its high precision, simplicity and without application of artificial weight. The correlation coefficient between Ca+2 and HCO3-, Mg+2 and PO4- were significantly high which might be due the presence of CaHCO3 and MgPO4 in the groundwater samples. The GWQI revealed a weak spatial dependence of groundwater quality.

The effect of treated spent wash on channel bed and groundwater qualities was investigated during 2014-15 at Unicol distillery as study area in district Mirpurkhas. For this purpose, samples of spent wash, soil/water were collected and determined for parameters related to physical and chemical properties. The impact of spent wash on channel bed and on the adjacent soils at different distances showed that highest soil EC (18.40 dS m-1) and TDS (11776 ppm) were determined for spent wash channel bed at surface soil and EC decreased with increasing distance from channel bed at sub-surface layers; while the highest overall soil pH (7.43) was observed at 450m distance at 30-45 cm soil depth. The highest total N (0.16%) and available K (0.53%) was observed at channel bed and at surface soil with highest available P (4.80%) at channel bed in sub-surface (15-30 cm) soil. The groundwater samples obtained from tube well and hand pump were also analysed for physical and chemical properties and compared with the spent wash from channel bed. The lower Na (1578.7 ppm) was determined in hand pump water samples than tube well water (2588.3 ppm); while highest (7050 ppm) in spent wash. The HCO3 was lower in tube well water (247.00 ppm) than hand pump water (430 ppm); and highest (6166.70 ppm) in spent wash. The Chloride (Cl) content was lower (2117 ppm) in hand pump water samples than tube well water (5259 ppm); and highest in spent wash (14097 ppm). The groundwater EC was lower (11.077 dS m-1) hand pump water than tube well water (17.262 dS m-1) and highest (47.090 dS m-1) in spent wash. Similarly, the lower magnesium (465.3 ppm) was determined in hand pump water samples than tube well water (553.3 ppm) and exceptionally high (1300.7 ppm) in spent wash. The SAR of hand pump water samples was lower (11.583) than tube well water (20.390) and outstandingly high (35.693) for spent wash. In case of calcium content, it was lower in tube well water (359.33 ppm) than hand pump water (593.33 ppm) and exceptionally higher in spent wash (764.33 ppm). It was concluded that soil EC and TDS were lower at farther locations from spent wash channel bed at sub-soils. The surface soil contained higher organic matter; no effect of spent wash on soil organic matter was recorded. The soil pH was relatively higher at spent wash channel bed and its adverse effects were noted upto 300-meter distance. Total N was slightly (P>0.05) higher at channel bed than distant locations, while phosphorus was significantly higher at spent wash channel bed. The available potassium was also significantly influenced by the spent wash; and P was higher at channel bed, and decreased at the farther locations adjacent to the channel bed. The EC level, Na, HCO3, Cl, Mg and Ca contents as well as SAR for spent wash samples were manifold higher than the tube well and hand pump water samples.

Agriculture is the back bone of Pakistan’s economy of Pakistan with 21 % contribution to GDP and providing livelihood to about 45 % of the total labor force of the country. The industry of Pakistan is mainly agro based (Economic survey of Pakistan, 2009-10). Due to change in climate and thereby extended drought, surface water resources of the country had reduced by 70% in 2003, compared with normal years (Kahlown et al., 2003). Unfortunately, canal water is not sufficient to meet requirements of soil and crop under intensive cropping system. A water quality study has shown that out of 560,000 tube wells in Indus Basin, about 70% are pumping sodic water which in turn is affecting the soil health and crop yield (Kahlown et al., 2003).The ground waters of different areas and depths have different types of salts which deteriorate the soil accordingly (Masood and Gohre, 2000). It is also reported that 73.38% (681) of the 922 water samples analyzed by the soil and water laboratory Vehari during the year 2006-07, were unfit for irrigation purpose, while 11.93% (110) were marginally fit and only14.21 (131) were found fit for irrigation purpose (Ashraf et al., 2008). According to the estimates, discharge of 50-60 % of the existing wells was brackish in nature (Ashraf et al., 2009) and still more formidable figures of Lahore district declaring that groundwater of 76.6% villages of the district was detrimental for crops and soil health (Ali et al., 2009).According to Shakir et al. (2002), 64 water samples were collected from new tube well bores from various locations of district Kasur to check the quality of under-groundwater for irrigation purpose. The results show that electrical conductivity of the samples varied from 524 to 5700 μS cm-1, sodium adsorption ration of the samples ranged from 0.49 to 26.00, while residual sodium carbonate ranged from 0.00 to 17.00 meL-1. Out of 64 samples, 26 samples were fit, 8 marginally fit and 30 unfit for irrigation.The successful crop production on sustainable basis, mainly depends on the quality of groundwater. The common characteristics considered are electrical conductivity (EC), sodium adsorption rations (SAR) and residual sodium carbonate (RSC) (Idris and Shafiq, 1999). The concentration and composition of dissolved constituents in water determine its quality for irrigation use. It is difficult to define the critical limits of EC, RSC and SAR because the effect of different qualities of water of soil health and crop yield is also governed by the type of soil, climate and management practices (Singh et al., 1992).Gravity of the situation of groundwater of the majority districts of Pakistan implies that something will have to be done without further loss of time to prevent the rapid conversion of productive fertile lands of Pakistan into unproductive barren lands. Besides, making investment on creating awareness among farming community about bio-saline technology/ saline agriculture by the private and public sectors, a watchful eye on the quality and quantity of ground water of every district of Pakistan by all the stakeholders and timely tackling the detrimental impact of brackish groundwater by using the available technology to the possible extent is imperative.

Valuation of water quality index (WQI) is one of the simplest, easily understandable, and efficacious techniques to evaluate the quality and suitability of water for drinking as well as other purposes. This research was aimed to investigate the drinking water quality of tube wells from different areas in Khulna City, Bangladesh, by developing the WQI. Water samples from 59 tube wells were collected from different locations during the pre-monsoon time. pH, electric conductivity (EC), dissolve oxygen (DO), total dissolved solid (TDS), chloride (Cl−), nitrate (NO3−), and total hardness of the collected water samples were analyzed for the calculation of WQI. The mean value for pH, EC, DO, TDS, Cl−1, NO3−, and total hardness was 7.30, 1650 μS/cm, 1.60 mg/l, 1188.7 mg/l, 414.6 mg/l, 0.029 mg/l, and 52.03 mg/l, respectively. The calculated WQI values for individual places were distributed spatially through mapping by using ArcGIS software. Based on the WQI values, the drinking water was categorized into excellent, good, poor, very poor, and unfit for drinking purposes. The calculated WQI values ranged from 40.11 to 454.37 with an average value of 108.94. Among all the groundwater samples, 11.86% were excellent, 54.24% were good, 23.73% were poor, 1.69% were very poor, and 8.47% were unfit for drinking purpose based on WQI. The results showed that the groundwater quality of most of the studied areas of Khulna city could be considered safe and suitable for drinking barring the elevated EC and chloride content in some areas. Since Khulna city is situated in the southwestern part of Bangladesh and gradually approaches toward the base level of the Bay of Bengal which might be the source of salt concentration in the groundwater of Khulna city, Bangladesh.

Bangladesh is a riverine country where arsenic bearing silt and sediments coming from Himalayas via different rivers (the Padma, Jamuna and Meghna) gets deposited in the groundwater aquifers at different locations of Bangladesh. Groundwater is the most dependent form of sources for drinking in this area, unfortunately arsenic is of extensive amount (more than 50 ppb) found in this groundwater. Fourteen water samples from different depth of tube well, 8 soil samples from topsoil (15 cm) and subsurface (30 cm) and 7 different types of food materials were collected from Alampur Village, Amjhupi Union at Megerpur district. Water samples are preserved by HNO‌3 for maintaining pH (2-3).Food and food materials were digested with HNO3- H2SO4 in order to determine the arsenic by Ag-DDTC, UV-visible method. The arsenic of tubewell water was beyond the Bangladesh acceptable limit and arsenic in food materials were with the limit of Australian food hygiene limit (1 mg /kg). Concentration of arsenic in topsoil (15 cm) was higher than arsenic in the subsurface (30 cm). The values of arsenic in food materials was lower, which indicated that arsenic from tubewell water is adsorbed in soil but not to propagate food materials. It might be due to the type of soil.

In present study, the quality of groundwater for irrigation in Bhopalgarh tehsil of Jodhpur district, Rajasthan was examined. Bhopalgarh tehsil bounded by Nagaur district to the north and east, Pipar city tehsil to the south, Jodhpur tehsil to the southwest and Bawadi tehsil to the west. Georeferenced sixty water samples of tube well/open well were collected from different villages where the waters are being used for irrigation for last few years. The water samples were analyzed for various chemical properties like EC, pH, major cations: Na+, Ca2+, Mg2+, K+ and anions: CO32-, HCO3-, Cl- and SO42-. Subsequently, residual sodium carbonate (RSC), sodium adsorption ratio (SAR), adjusted SAR, potential salinity and Mg/Ca ratio were also calculated. The quality of irrigation water was categorized on the basis of salinity (EC), sodicity (SAR) and alkalinity (RSC) into 4 salinity (C-1 to C-4) classes, 4 sodicity (S-0 to S-3) classes and 3 alkalinity (A-1 to A-3) classes, respectively. Besides this, the quality of irrigation water was also categorized on the basis of the EC, SAR and RSC into six classes viz. good, High-SAR saline, marginally saline, marginally alkali, alkali and highly alkali. The results showed that 21.66 percent water samples were good, 15 percent water samples were marginally saline, 48.33 percent water samples were High-SAR saline, 8.33 percent water samples were marginally alkali, 3.33 percent water samples were alkali and 3.33 percent water samples were highly alkali in nature and it is found that most of the irrigation water came under high-SAR saline category.

Nitrate as an important water pollutant, causing eutrophication was analyzed in Pakistan at different water sources (hand pump (HP), bore hole (BH) and tube well (TW)) to assess the contamination level caused by NO3-. NO3- concentrations in the HP water samples were 31 mg L-1 to 59 mg L-1, in BH 20 mg L-1 to 79 mg L-1 while in TW water samples it was between 29 to 55 mg L-1. The association of NO3- with other selected parameter in groundwater can be determined by using statistical approaches. Different physicochemical parameters (pH, electrical conductivity (EC), temperature and dissolved oxygen (DO)) were studied in groundwater samples of the research district. The Pearson correlation coefficient (r) for groundwater characteristics were calculated. Hierarchical Cluster Analysis (HCA) was used to categorize samples based on their groundwater quality similarities and to find links between groundwater quality factors. The key relationship of the groundwater for HP samples on EC and TDS (r = 1) had a great correlation, while all other parameters correlations were lower (r = 0.40), BH's parameters on WT and WSD (r = 0.57), WT and pH (r = 0.57), EC and DO (r = 0.50), DO and TDS (0.50), EC and TDS (r = 1) had a quite high correlation, while all other parameters correlations were less than (r = 0.40), on the other hand, tube well parameters on TDS and EC (r = 1) had a perfect correlation, DO and pH (r = 0.75) parameters correlations were less than (r = 0.40).

Good-quality water and food are the basic needs of humans, plants, and animals. Polluted groundwater and soil directly and indirectly affect organisms, which is the main environmental concern. In the current study, standard protocols of atomic absorption spectrometry were adopted for the investigation of selected metals (lead, chromium, and iron) in the collected groundwater and soil samples. The Pearson correlation coefficient (r) applied to groundwater and soil samples shows a positive perfect correlation among water parameters (conductivity and total dissolved solids) in all three sources. In the hand pump samples between water table (WT) and water source depth (WSD), Pearson correlation coefficient (r) value was found (r = 0.87) while between EC and TDS, it was r = 1. Similarly, in the bore hole samples between WT and WSD (r = 0.66), EC and TDS (r = 1), EC and Cr (r = 0.70), and TDS and Cr (r = 0.70), which showed weaker correlation. In the tube well samples, correlation between EC and TDS was high (r = 1). The correlation coefficient (r) values of the soil parameters in the hand pump (soil) samples between Fe and Cr (r = 0.86), in bore hole samples between Fe and Cr (r = 0.77), in tube well samples between Fe and Cr (r = 0.69), while all the other parameter correlations were found lower (r = 0.60). Between electrical conductivity and total dissolved solids, high relation has been observed between them (r = 1). Overall, results showed that in most of the studied samples, contents of the target metals were found above the allowable limit set by the World Health Organization (WHO) and the United States Environmental Protection Agency (USEPA).

A liquid–liquid extraction (LLE) method was validated as per SANTE/12682/2019 guidelines for gas chromatography–mass spectrometric (GC–MS) determination of thirty-six multiclass pesticides in environmental waters. Seasonal (summer, monsoon, and winter) effects on the magnitude of pesticide residues in environmental water (river, pond, and tube well) of six different urban areas of Nadia and North 24 Parganas districts (New alluvial zone, Eastern India) was monitored for subsequent risk assessment. Total 288 water samples (96 each of river, pond, and tube-well) irrespective of locations and seasons were monitored for multiclass multi pesticide residues during the experiment. Each sample (750 mL) was extracted with ethyl acetate/dichloromethane (8:2) liquid–liquid partitioning and filtration (0.22 μm nylon filter paper) and total residue was reconstituted in acetone (1 mL) for GC–MS analysis with developed and validated method resulting satisfactory recovery percentages (77.84–118.15%). The maximum no. of organochlorine (OC) and organophosphorus (OP) pesticide residues were dominated in river and pond water irrespective of seasons and monitoring sites. About 74% of river water samples were found to be contaminated with concerned pesticides in variable magnitudes. Monsoon (July to October) season was highly alarming with the highest presence of total pesticide residues in different types of environmental waters. Risk quotient (RQ) [acute and chronic] was also evaluated in pond and river water as sometimes used for drinking purposes. RQ value (5900) of total endosulfan indicates the highest risk of chronic toxicity to river fishes. Seven water samples from tube-wells were also monitored and found to be contaminated with butachlor and chlorpyriphos in non-significant amounts (

Quality of drinking water is associated directly with the health of mass population. Therefore, study on radiation level in groundwater has been taken up around the Sohna fault line, Haryana state, India. Uranium concentration has been measured in drinking water samples collected from sources such as hand pump, tube well from different depths around the Sohna fault line, using LED Fluorimetry Technique. Uranium concentration in study area varies from 0.10 µg/L to 223.16 µg/L with an average value of 22.09 µg/L. The average value of uranium concentration is within the safe limit recommended by World Health Organization (WHO, 2011) and Atomic Energy Regulatory Board. The annual effective dose has also been measured in all the water samples and is found to be below the prescribed dose limit of 100 µSvy−1 recommended by WHO (2011). Risk assessment of uranium in water is also calculated using life time cancer risk, life time average daily dose and hazard quotient. The high uranium concentration observed in certain areas is due to interaction of ground water with the soil formation of this region and the local sub-surface geology of the region.

Total 26 samples, 6 from river, 7 from deep tube well and 13 from shallow tube wells were analyzed for the isotopic composition and chemical composition of the water at different sources. The main focus of the study was to assess connection between aquifers, and recharge zone analysis of the local groundwater system in the Siraha and the Saptari Districts, west of the Koshi River. The δ18O composition of the Koshi River was found to be the lightest whereas the shallow tube wells at Haripur and Shambhunath were the heaviest. The δ18O composition at many locations showed identical values showing the correlation of water within the aquifers and also with the surface water. Based on the plot of δ18O vs δ2H, the shallow tube well at Asanpur and the deep tube well at Jamdahawere suspected to be recharged from the Kharak Khola. Similarly, the deep tube wells at Lalpur and Kusaha, the shallow tubes wellat Asanpur, Tudkiya and Raghunathpur, and the Mahuli Khola and the Khado Khola are interconnected. The deep tube wells at Tudkiya, Dhangadhi and Phulkakatti might have interconnection with the shallow tube wells at Khoriya and Golamukhsar.

High iron (Fe)–bearing groundwater in Bangladesh contaminates the groundwater aquifer with subsequent health risk. All the populations of Rangpur City Corporation (RpCC) depend on groundwater for their drinking, domestics, and irrigation purposes. This study investigates the concentration of Fe in groundwater of RpCC with special attention on the associated health risk of the dwellers residing in it. Stratified random sampling was adopted to collect 101 water samples from 33 wards of which each ward has 3 samples from tube well to identify Fe concentration using atomic absorption spectroscopy (AAS). The data are analyzed following several statistical technique and compared with Bangladesh and WHO standard values. Maximum mean concentration was found in ward no. 11which is 1.620 mg/L and minimum mean concentration was found in ward no. 6 which is 0.006 mg/L. Single Factor Index (SFI) and Nemerow Index (NI) were applied to analyze the quality of groundwater for the whole data set. Hazard Quotient (HQ) and Hazard Index (HI) were used to assess health risk and it ensures that the females of the study area are more susceptible to iron health risk than the males. However, geostatistical analyses using ArcGIS-10.5 were used to show the spatial distribution and autocorrelation among several variables. Spatial distribution maps show important visualization for understanding Fe concentration zoning, distribution of quality indices, and health risk. The findings of this work will help the city corporation authority, environmental planner, and policymaker to understand the potential health risk due to Fe concentration.

Radon (Rn) is a radioactive, odorless, and colorless gas which has a half-life of 3.83 days. One of the main sources of Rn which is directly consumed by the population is Groundwater (Tube well, Bore well, Hand pump). Rn gas is found naturally in rock, soil and water and can be considered as main health risk factor in terms of lung cancer, stomach diseases, leukemia and childhood cancer. The objective of this study was to determine the concentration of Rn in the drinking water sources, appraisal of health risk for children in District Bannu, Pakistan. Total of 98 drinking water samples were analyzed by using RAD-7 detector. The experimental data was statistically analyzed by using Pearson’s test. The experimental and epidemiological data of the study area are shown on map using ArcGIS version 10.5. The analytical results show that Rn in drinking water was found varying from 10.1 Bq/l to 53.1 Bq/l with the average highest and lowest depth of 60 ft to 550 ft respectively. Pearson’s test was used to show the concentration of Rn verses the depth of the water sources so +1 positive linear correlation was observed among the depth of water sources and the concentration of Rn. Out of 98 drinking water samples 40 sample were above the maximum contaminant level of 11.1 Bq/l (MCL) set by WHO, 2002. The effective doses (AED and DEing) for children ranges from 0.00001 to 3.792 mSv/y which exceeds the Permissible Exposure Limit (PEL) of Rn (0.1mSv/y) in 30 drinking water samples . On the basis of analytical results Rn high concentration areas are shown on the map using IDW model of interpolation and health risks were shown in areas where Rn content was above the maximum contaminant level. High correlations of diseases related to Rn were observed amongst the residence of the study area. Gastrointestinal diseases, brain tumor, lung cancer and kidney diseases were observed among the children of the study area. From the overall analysis it was observed that high Rn concentration in drinking water may cause substantial health damage in children after long term exposure.

India’s agricultural economy has undergone profound transformation in the past 50 years with the rapid spread of groundwater irrigation. The tube well revolution has democratized irrigation, made famines history, helped alleviate agrarian poverty and made India food secure. However, the spread of private tube wells has cannibalized canals and tanks. The large-scale withdrawal of groundwater has caused acute groundwater stress in several parts of the country, leading to adverse environmental and sustainability challenges. Unlike the United States, Australia, and Spain, where tube wells are instruments of wealth creation in industrial agriculture, in India groundwater governance pits livelihoods of the poor against environmental protection. This study explores this unique challenge. It discusses several efforts undertaken to effectively manage groundwater such as direct regulation, indirect levers like energy pricing and rationing, and community-based groundwater governance. It emphasizes on the arrival of solar irrigation and its potential to reform the perverse energy-groundwater nexus. The paper stresses on the need to move away from resource development to resource management mode to solve the groundwater challenge.

In this chapter, various artificial recharge techniques and its analysis would be studied in detail. Artificial recharge was carried out for an industrial site located in Vadodara, Gujarat. As per geological survey it was found that the study area had upper alluvial soil formation of about 30–40 m depth and then the underlain by weathered and massive basalt. Ground water was the only source of water for the manufacturing process in the industry, which lead to over exploitation of it. Continuous pumping of water in this area had resulted in ground water depletion by 1–2 m and deteriorating water quality in the in tube wells. Hence, to improve the ground water condition, artificial replenishment through rain water was carried out by the factory. Out of 17 tube wells dug in the factory premises four tube wells were taken under first phase of artificial recharge of ground water. In this phase-I two unique methods of ground water recharging system were designed and executed. In which two tubewells were recharged by Percolation Tank and two by Roof Top Rain Water Harvesting. For this artificial ground water recharge project various data were collected like periodical water level in tube wells, daily water level observation in percolation tank, daily rainfall data and evaporation data. Also aquifer stratification of the study was conducted through resistivity survey and lithological data. Through water budgeting method daily volume of ground water recharge was found out as 14 m3/day. By pumping test average permeability of an aquifer system was estimated as 4 m/day. Estimated volume of water recharged through Roof Top Rain Water harvesting was 9466 m3.The calculated volume of water recharged through combination of percolation tank and two recharge well was found as 2040 m3. An average recharge rate was of 16 mm/day was obtained by combined percolation tank and recharge wells system. The total recharge volume in factory was about 10% of total pumping and total artificial recharge was about 2% of total pumping. Whereas total recharge was about 16% and artificial recharge was 3.5% of total rainfall. It was concluded that there was a rise in water level on average of 0.4–3.5 m. Tube well recharging technique was successful in increasing ground water level and improving the quality of ground water. Roof top rain water harvesting technique is found to be more effective for recharging the ground water by tube wells.

Arsenic is found in minerals of earth crust in variable concentration throughout different geographical concentration. Leaching of arsenic from earth crust cause groundwater arsenic contamination. It was found in variable organic and inorganic form known as arsenate and arsenite compounds. Groundwater arsenic concentration were very high in Ganga-Meghna and Brahmaputra plain, it was very high in Bangladesh. In 1983 the first report on groundwater arsenic contamination was highlighted. After that many research scientists worked there, but research findings of Dr. Dipankar Chakraborti and Dr. Guha Majumdar have significant contribution in awareness and detection of groundwater arsenic contamination in West Bengal. They have even highlighted effect of groundwater contamination on Public health of West Bengal. West Bengal is severely affected with arsenic contamination and now reports on crop contamination are alarming. According to 2006 reports only 6 districts are arsenic contaminated out of total 18 districts. While according to 2016 reports 9 districts were reported with high level of arsenic contamination in Bengal. Still it was found in new areas. Severe arsenic contaminated districts are Malda, Murshidabad, Nadia, Howrah, Bardhaman, Hoogley, North and South 24 Pargana. Severe health hazards were reported in these districts including skin pigmentation, arsenicosis, peripheral vascular disease, blackfoot disease, skin lesions, and cancer. Many types of mitigation approaches were practiced from last three decades in West Bengal including traditional methods of rainwater harvesting, dug well, deep tube well, and surface water use, but all have limitations and not found very much suitable for rural household uses. Government of West Bengal supplies treated Ganga water in many villages as arsenic remedial measures. Government also puts some deep tube well below 150 m in many villages for providing safe drinking water to rural people at community level. These techniques are very costly and not feasible at household level. Many technologies were tried including oxidation method, coagulation-flocculation method, and adsorption techniques for removal of arsenic from groundwater but they also have some limitations. In current scenario adsorption techniques using oxy hydroxides and iron hydroxides dominate the current market in West Bengal. Use of biological arsenic removal techniques through microbes is advancing scope in development of future arsenic mitigation techniques.

The scarcity of freshwater is escalating higher than the predicted level in India alongside the other countries in the world. The surface, subsurface and groundwater resources are gradually reducing in quantity and quality concern. The states and union territories of the western, southern and central India are already severely suffering from the scarcity of freshwater. Rate of groundwater extraction accelerated after the implementation of the green revolution and urban-industrial development. The river’s natural flow has been diverted and protected for socio-economic development. Therefore, the lower riparian states are deadly affected by ecological and hydro-geomorphological perspectives. The fisheries have been widely adopted in those areas as an alternative to traditional crop cultivation, which extract more groundwater for freshwater supply and enhance the rate of groundwater depletion. Moreover, the rainwater recharge into the soil layer as well as in the groundwater table has been gradually reducing due to concretized urban infrastructural development. The surface runoff becomes accelerated, enhancing the soil erosion rate. In India, about 75% of total water bodies have been polluted from domestic wastes. Besides, about 80% of rural people are compelled to use unsafe water, which resulted in the death of more than 700 children per year from diarrhoea. In this situation, India achieves the third place in the world in terms of water export. In such juxtaposition condition, about 60% and 85% of irrigation water and drinking water supply came from the groundwater, respectively. Recently, over 60% of tube wells are malfunctioning due to excessive rate of groundwater depletion. The su ffering of the people is tremendously increasing concerning the availability of drinking water and irrigation water. People are extracting groundwater from the far depth to overcome the crop failure and drinking water problem. But, the severity of water scarcity becomes enhancing year after year in conjunction with global warming and climate change. In this concern, the government has taken different water scarcity preventive measures in individual household level to the regional level. Now, the main motto is to execute the 3-R concept (recycle, reuse and recharge) in association with the other various techniques of water storage (like rainwater harvesting) and groundwater recharge (like percolation tank, recharge tube well). In addition, awareness programmes are being campaigned from the grass-root level to increase the efficiency in water utilization among the people.

The present study aims to examine the long-term groundwater behaviour in Haryana which is an agriculturally developed state of north-west India. For this study, groundwater level data has been acquired from the Groundwater Cell, Department of Agriculture, Haryana, for the period 1990–2013. By using this data, declining/rising groundwater level areas, groundwater balance, net groundwater balance and net rise/fall of groundwater level have been computed for the state as a whole and three climatic zones, i.e. sub-humid, semi-arid and arid. The analysis shows that approximately 77% area of the state has demonstrated a decline in groundwater levels during the study period. The state as a whole has experienced a fall of 0.7 cm/year in the average net annual groundwater levels with the highest decline in Fatehabad (5.1 cm/year) and Mahendergarh (4.1 cm/year) districts. Remarkably, northern and southern districts of the state are facing a problem of a sharp decline in groundwater levels, whereas central parts are experiencing a continuous increase leading to waterlogging problems. In sub-humid zone, about 95% area has witnessed a decline in groundwater levels followed by semi-arid (85%) and arid (77%) zones. Overall, the state has a negative groundwater balance, i.e. −1361.6 (00 ha-m). Therefore, urgent measures need to be taken up for sustainable utilisation and management of groundwater resources both at field and regional scale.

The overuse of water from aquifers has resulted in a decrease in the groundwater table. Gopali, a small village on the outskirts of Kharagpur, has some clean drinking water requirements. Hence, the goal of the study was to determine the depth of the aquifer in this location that would generate a large volume of water, so that a tube well could be drilled and provide enough water for the settlement. As a result, we identified seven favorable locations for Vertical Electrical Soundings in order to better understand the area's subsurface geology and assess the probability of an aquifer (VES1 to VES 7 respectively). The study dealt with the collection of resistivity data, assessing it, and survey the aquifer layers using this method. In this situation, the electrode spacing was determined using a Schlumberger electrode approach. IGIS DDR3 DC resistivity meter with 600m transverse extension (AB) was used to conduct the exploration at Gopali, block Kharagpur-I, Paschim Midnapore district, West Bengal, India. Because of the significant lateral expansion, over 150m of current penetration data was recorded. Clay-sand intercalations with medium to fine-grained sand were discovered in this sedimentary area, and these alterations were mostly observed between 70 and 150 meters.

Development of private tube wells and groundwater markets have transformed the farming systems of smallholders in Pakistan, leading to the realization of economic incentives for higher outputs, profits, and sustainability. This chapter aimed at identifying significant factors affecting farmers’ choice of tube well ownership. The multinomial logit model was applied to investigate the factors that drove farmers’ choice among the following three options to access groundwater namely, (1) exclusive ownership of a tube well, (2) sharing a tube well, and (3) buying water from informal groundwater markets. Data from 224 households consisting of 84 exclusive owners, 65 tube well shareholders, and 75 water buyers were analyzed. The results showed that decision maker’s age, groundwater depth, and salinity perception increased the odds of choosing the shared tube wells over exclusively owned tube wells. The price of groundwater significantly decreased the odds of opting for shared tube wells. The odds of purchasing water significantly increased with an increase in salinity. On the other hand, land size, price of groundwater, and ownership of tractor decreased the odds of purchasing water. The findings implied that shared tube wells were more preferred over exclusive tube wells in deeper water table areas and where water was more saline. In the given circumstances of falling groundwater levels, and decreasing quality of groundwater, the focus should be shifted to sustainable use and management of these shared tube wells and purchased water to safeguard the groundwater resources and farm profitability in the long run.

This chapter examines the effects of such power sector reforms on the functioning of groundwater markets at the local level by comparing the cases of Gujarat and West Bengal. In Gujarat, an innovative power sector reform program (called Jotigram Yojona) was launched. The West Bengal state government, on the contrary, introduced a metering system to agriculture in place of the flat tariff while abolishing the electric tube well permit system. Consequently, the groundwater markets shrunk and/or the water charges paid by less resourceful farmers to the well owners increased in both states. The results imply that the power sector reforms, although they contributed to the reduction of the nexus problem, produced severe ill effects upon the farmers placed in weaker market positions.

Groundwater resources are crucial in sustaining agro-ecosystems and ensuring food security in many parts of the world, including Pakistan. However, the sustainability of groundwater resources is subject to a number of challenges, including over-extraction, deterioration in quality, and vulnerability to the impacts of climate change and population growth. Given the current state of groundwater resources in Pakistan, policymakers seek to manage groundwater resources by limiting groundwater extraction. To achieve this goal on a national scale, it is important to understand the determinants of the decisions made by local farmers in respect of tube-well adoption. This study investigates smallholder farmers’ decisions to adopt tube-well technology in the face of dwindling groundwater resources and falling water tables. Analysis is based on a cross-sectional survey of 200 rural households from the arid to semi-arid predominantly groundwater-irrigated plains of the Punjab province, Pakistan. It is found that farmers will adopt tube-well technology in pursuit of reliable irrigation water supplies to hedge against production risks but not against the risk associated with unfavourable extreme events (downside risk) such as total crop failure. This suggests that the adoption decision is influenced by the expected long-term rather than the short-term benefits. This paper draws attention to the need to regulate groundwater resource exploitation by requiring the use of tube-well technology to be accompanied by irrigation water-efficient techniques and technologies.

Hydrogeochemical investigation was carried out in the Western Doon valley, to understand the geochemistry of the groundwater and to assess the overall physic-chemical characteristics. To attempt this goal, 50 groundwater samples of dug well and tube well were collected using pre-cleaned polyethylene containers from the different geological formations of the study area. The physical and chemical parameters of the analytical results of groundwater samples were compared with the standard guideline values recommended by the World Health Organization for drinking and public health standards. Thematic layers pertaining to Ca2+, Mg2+, NO3- and total hardness (TH) were generated using GIS platform. The hydrochemistry of groundwater quality for drinking purpose was evaluated by plotting the cations, anions in the Piper's Trilinear diagram, which indicates the alkaline and weak acids dominance, and carbonate hardness exceeds 50%. Expanded durov diagram implies Ca2+–HCO3- dominance, indicating recharging of water in sandstone aquifer. Based on the hydrogeochemical analysis for irrigation quality, certain parameters like carbonate hardness, sodium adsorption ratio, sodium percent, salinity hazard, residual sodium carbonate, Kelley's ratio, index of base exchange and permeability index were calculated. Besides this, a comparison of the groundwater quality in relation to drinking water quality standards shows that most of the groundwater samples are good for drinking as well as irrigation purposes and controlled by lithology apart from other local environmental conditions as the concentration of the cations and anion increases in the post-monsoon season. The results of hydrogeochemical are helpful to generate the baseline information and roadmap for future research on groundwater resources to assess the water quality in relation to agricultural and domestic uses in the Western Doon valley.

The estimation of groundwater abstraction at different spatial scales of lower canal system in Punjab, Pakistan was made for Khurianwala and Mungi distributaries to quantify groundwater abstraction, during 2014-2015 to identify the share of canal water in relevance to groundwater, to minimize the crop water demand and to access the constraints in the implementation of demand-based irrigation system in lower Chenab canal system. Information in survey captured on a questionnaire including Bore depth, Water table depth, Head range, Diameter of pipe, Brand of the pump, Water quality, Pumping hours for the whole year and cost of tube well installation was obtained during this survey. This abstraction data calculated through the ground trothing was corroborated and reconfirmed through R.S and GIS. After review of the literature, analysis of the situation & interpretation of results, it revealed that Ground water abstraction is significantly higher at the tail of the distributary especially at peak months. Moreover, Groundwater intensive survey gave much better estimation and an assessment on quantification of groundwater abstraction and sharing on canal water. Constraints for the adoption of demand based irrigation system were also studied to make recommendations.

Underground tube-well water is one of the most important sources of pure drinking water in the world. Drinking water contamination with heavy metals (iron and arsenic) is a burning question nowadays for public health and also environmental perspectives. Our present task is for determination of iron and arsenic concentration in ground tube-well with possible health risk in Bangladesh. The water samples were collected from Tangail district of Bangladesh during January 2017. Iron and arsenic concentration were analyzed by using Atomic Absorption Spectrophotometer. Iron concentration ranged from 4.483 to 20.698 mg/l where arsenic concentration was obtained from

Water quality information is needed to assess the state of water contamination in a variety of community, including those that rely primarily on unimproved underground sources of drinking water. The study was carried out with an aim to assess the quality of ground water in particular sites of the Kathmandu valley. The ground water samples were collected from shallow well, tube well and deep tube wells located at specific places of the valley. The research was focused on physiochemical and bacteriological analysis of underground water from sites near to Bagmati river (≤20 meters) and from sites far from Bagmati river (>50 meters). The sampling sites were scattered from Sinamangal to Minbhavan. Total sample size was 100, with 50 in each stratum. Study processing was done during the period from February 2013 to May 2013. Six physiochemical parameters namely pH, Conductivity, Ammonia level, Chloride level, Nitrite level, Nitrate level and Biological parameters (Coliform and Fecal coliform) of each sample was tested. Based on the research work, it was recorded that the underground water close to river (≤20 meters) has comparatively high physiochemical and biological parameter (Fecal Coliform) than underground water that were farther from the river (>50 meters). Fecal Coliform was predominant 58% (29/50) in water nearer to river rather than in water farther from the river 20% i.e. (10/50). Similarly, the values of physiochemical and biological parameter increased comparatively with more distance i.e. ≤10 meters from river. The finding indicated that the underground water near to river is more polluted than far from the river.Nepal Journal of Biotechnology. Dec. 2017 Vol. 5, No. 1:21-26

This research integrates quantitative data of underground and sub-surface sources of drinking water from two coastal union Gabura and Munshiganj of Shyamnagur upazila of Satkhira district. Four drinking water sources have been selected and sampled during dry season when the salinity rate is generally high. A total of 22 water samples have been collected of which 6 from protected pond, 6 from tube well, 6 from rainwater and 4 from pond sand filter (PSF). The average pH of tube well water, protected pond water, pond sand filter water and rain water were 6.59 (±.05), 6.46 (±1.03), 6.60 (±.52), 5.95 (±.87), respectively. The average EC (μs cm-1) range of tube well water, protected pond water, pond sand filter water and rain water were 2059.16 (±49.43), 1756 (±14), 769 (±94.27), 64.33(±59.91) while the TDS (ppm) range were 1319.97 (±31.69), 1125.64 (±913.46), 492.94 (±60.43) and 15.38 (±118.59) respectively. The maximum concentration of salinity was found in tube well water which was 1.37 (±53) ppt. Most of the protected ponds were highly contaminated with sulphate and it ranges from 84.64 to 218.25 ppm. The average number of fecal Coliform in protected ponds were 1650 100 m l-1 of water while in PSF source pond 2350 100ml-1 and collection point 1.5 100ml-1.J. Environ. Sci. & Natural Resources, 10(1): 101-108 2017

Integration of satellite-based remote-sensing data and the geographical information system (GIS) for the exploration of groundwater resources has developed a revolution in the field of groundwater research, which assists in evaluating, observing, and preserving groundwater resources. In the present paper, various groundwater potential zones for the assessment of groundwater recharge zone availability have been delineated using remote-sensing and GIS techniques. Landsat 8 satellite imageries were used to prepare various thematic layers such as: lithology, altitude, slope, and groundwater table map from the inventoried tube well data. These layers were then transformed into raster data using the feature to raster converter tool in the ArcGIS 9.3 software. The raster maps of these factors are allocated a fixed score and weight computed from multi-influencing factor (MIF) technique. Subjective weights are assigned to the respective thematic layers and overlaid in GIS platform for the identification of potential groundwater recharge zones within the study area using weighted overlay index analysis (WOIA). The groundwater potential zones thus obtained were divided into five categories, viz., very poor, poor, good, moderate, and excellent zones. The results reveal that the areas of excellent groundwater potential are estimated to permit precipitated water percolates into subsurface and ultimately contributes to recharge the groundwater. These results suggest that the high potential zones will have a key role in future expansion of drinking water and irrigation development in the study area.

Salinity in the drinking water of coastal Bangladesh results from a severe socio-economic, environmental and human health safety crisis. In this paper, we analyzed 120 tube well water samples from southeast coastal Bangladesh for eight trace metals (TMs). Contamination, quality and risk of TMs to human health of tube well water influenced by salinity-induced fluorescent dissolved organic matter (FDOM) were assessed using multiple pollution indices, GW quality index (GWQI), traditional health risk, and PARAFAC models. The mean values of EC, Fe, Cd, Cr, and As surpassed the limit set by local and international standards with significant spatial variations. The results of the GWQI showed that 52.5% of the samples were within the moderate-poor quality range in the study region. PARAFAC modeling identified three groundwater FDOM constituents with a coupling of humic acid (HA), fulvic acid (FA), and degraded fulvic acid (DFA)-like substances. Moreover, the positive correlations among EC, TMs, HA, FA, and DFA proved that salinity-induced FDOM had significant contributions to the dissolution potential of contaminants in the aquifer, hence increased the mobilization of TMs. Health risk models suggested that children are more susceptible to the non-carcinogenic and carcinogenic risks than adults at the community level. The carcinogenic risks of Cd, As, Pb, and Cr via oral exposure pathway indicated the highest carcinogenic risks for both adults and children. The findings also indicated that the salinity-derived FDOM-TMs complex is the key driver to groundwater co-contaminations and elevated health impacts. Besides, high concentrations of Fe and As are the key causal issues for sustainable water safety. Thus, strict water management and monitoring plans require preventing these contaminants for sustainable community well-being in the coastal region.

The study was carried out to understand the hydro-geochemistry and ground water quality in the Rajshahi City of Bangladesh. A total of 240 groundwater samples were collected in 2 years, i.e., 2009 and 2010 covering the pre-monsoon, monsoon and post-monsoon seasons. Aquifer soil samples were collected from 30 locations during the monsoon in 2000. All the samples were analyzed for various physicochemical parameters according to standard methods of analysis, these includes pH, electrical conductivity, total dissolved solids, total hardness, and total alkalinity, major cations such as Na+, K+, Ca2+, Mg2+, and Fe2+, major anions such as HCO3 −, NO3 −, Cl−, and SO4 2− and heavy metals such as Mn, Zn, Cu, As, Cd and Pb. The results illustrated that the groundwater was slightly acidic to neutral in nature, total hardness observed in all samples fall under the hard to a very hard category. The bicarbonate and calcium concentration in the groundwater exceeded the permissible limits may be due to the dissolution of calcite. The concentration of calcium, iron, manganese, arsenic and lead were far above the permissible limit in most of the shallow tube well samples. The study found that the major hydrochemical facies was identified to be calcium-bicarbonate-type (CaHCO3). A higher concentration of metals including Fe, Mn, As and Pb was found indicating various health hazards. The rock–water interaction was the major geochemical process controlling the chemistry of groundwater in the study area. The study results revealed that the quality of the groundwater in Rajshahi City area was of great concern and not suitable for human consumption without adequate treatment.

Arsenic (As) contamination in different areas of the world has been reported, which poses serious health threats to humans by its different routes of exposure. There exists comparatively rare data regarding arsenic level in groundwater of Punjab, Pakistan, which is normally used for drinking purpose. Therefore, the present study was planned to assess the contamination of arsenic in the drinking water of district Vehari in Punjab, Pakistan. A total of 156 drinking water samples were taken from different previously unexplored (rural and urban) areas. Various groundwater sources (electric pump, hand pump, and tube well) were targeted at different depths (50–350 ft) of the three tehsils (Burewala, Vehari, Mailsi) of district Vehari. Drinking water samples were subjected to measurement of the arsenic level, as well as other parameters of water were also checked including pH, electrical conductivity, chloride, cations, carbonates, and bicarbonates. It was found that 95% of groundwater samples were unfit for drinking purpose, because some areas of district Vehari were found with arsenic levels higher than World Health Organization (WHO) safe limit of As (10 μg/L) in drinking water. Arsenic-induced health risks were also estimated with respect to average daily dose, hazard quotient, and carcinogenic risk for the people who were relying on arsenic-rich groundwater for drinking purpose. It is found that the people of district Vehari are at the serious carcinogenic health risk. This study highlights that urgent management and monitoring measures are imperative for the people in the study area, in order to minimize the arsenic-mediated health effects, as well as to develop effective remediation strategies for arsenic-contaminated drinking water.

This study assessed arsenic health risk to the local residents through oral and dermal exposure pathways of drinking water and to investigate source apportionment of groundwater pollutants using multivariate statistical techniques in the Chapai-Nawabganj district, Bangladesh. Groundwater samples collected from shallow tube well and dug well at the depth ranges (15-60 m) were analyzed for physio-chemical parameters and trace elements. Most of the studied physio-chemical parameters were found within their respective permissible limits. However, total As, Fe and Mn concentrations exceeded Bangladesh and WHO guideline values. The assessment of arsenic health risk reveals that children as compared to adults are found at a higher risk as the values of hazard quotients (HQ) >1 in the most of the groundwater samples. This level of arsenic contamination should have medium to high chronic risk and medium carcinogenic risk when compared with US EPA guidelines which can cause serious health hazard. The results of principal component analysis (PCA) and factor analysis (CA) indicate that geogenic (interaction of water and basement rock) and anthropogenic (agrochemicals, agricultural fertilizer and domestic sewage) sources are responsible for variation in arsenic and other physio-chemical parameters in the groundwater aquifer of the study area. Furthermore,the inter-correlation of arsenic with metals and ions were also calculated by correlation matrix and linear regression analysis. The outcomes of this study will help to meet the challenge of sustainable groundwater quality management in Bangladesh and enhancing better vision of potential health risk of local inhabitants in the study area.

Groundwater contamination is gaining more concerns due to its direct and/or indirect impact on public health. Groundwaters from various sources are commonly used to irrigate vegetables in Maiduguri, Borno State. In this study, the physicochemical qualities of groundwater collected from 20 randomly selected tube wells in Maiduguri were evaluated for their suitability or otherwise for irrigation purposes. Selected wells were extensively used as sources of irrigation water. Standard procedures were followed during the analysis. The results revealed that the mean values of pH (6.6 to 8.0), calcium (2.6 to 5.2 meq/l), magnesium (2.6 to 5.0 meq/l), sodium (2.2 to 7.5 meq/l), carbonate (0.5 to 1.3 meq/l) , bicarbonate (1.8 to 5.2 meq/l), chloride ( 0.9 to 2.9 meq/l), sulphate (2.8 to 9.8 meq/l), potassium (0.3 to 0.9 mg/l), Boron (0.1 to 0.6 meq/l) and nitrogen (1.9 to 4.8 mg/l) were all found to be within the acceptable limit for suitability of water for irrigation use based on Food and Agriculture Organization (FAO) recommendations. The results further revealed that, the values of electrical conductivity (0.3 to 0.7 ds/m), total dissolved solids (192 to 448 mg/l), sodium adsorption ratio (0.40 to 3.62), residual sodium carbonate (-1.3 to -7.6 meq/l), magnesium adsorption ratio (35.80 to 49.06%) and Kelly ratio (0.10 to 0.90) of the samples were within the safe limit recommended for irrigation water use. The quality of tube well waters in the study area can thus be regarded as good, and suitable for irrigation purposes, but similar analysis should be conducted on a routine basis to monitor the qualities of the waters toward safeguarding public health. Key words: Tube well waters, physicochemical qualities, irrigation suitability, public health, Maiduguri.

Water availability for domestic and irrigation purpose is the lifeline of the society and plays a dominant factor in the agriculture development of the country. Though Nepal is rich in water resources, nation-wide surface water irrigation network is yet to be established to meet the year round irrigation. The readily available shallow groundwater is considered as vital in meeting the domestic and irrigation water need. The shallow groundwater irrigation in the country has been emphasized and this system is contributing in the irrigation facility at present. Understanding the potential of shallow groundwater would support to further develop the shallow irrigation cluster wells in the Indo-Gangetic Plain. A systematic and comprehensive tube well database in GIS platform serves better for the groundwater potential delineation purpose. Thicknesses of aquifer material, well yield, hydraulic conductivity, water table are some of the decisive parameters for delineating the groundwater potential areas. However, all parameters are not always available. In such situation, the analysis can be performed with the thickness of aquifer material and yield of the well that are widely available in the reports of concerned organizations. Present study shows the GIS based analysis of aquifer parameters in one of the Terai districts of Nepal to delineate the shallow groundwater potential zones. The method adopted in the present study can be applied in other parts of the country, which would better serve for effective development planning and providing irrigation service to the farmers.Journal of Institute of Science and TechnologyVolume 22, Issue 1, July 2017, Page: 104-109

Being the world’s most precious natural and valuable resource, groundwater remains largely unexploited for agricultural development in drought-prone western region of West Bengal, India. In drought-prone areas, micro-watershed-based development strategy may be considered as the best practice for integrated development. Keeping in view the above perspective, we select the micro-watersheds of Kumari River Basin of Purulia District, the westernmost and semi-arid region of West Bengal, for better water resource management. Supply of sufficient water resource in this region may offer more food security alternative to rain-fed subsistence farming. That is why the present study has been carried out to evaluate the potential zones for groundwater targeting in the Kumari River Basin with the help of morphometric analysis using an integrated remote sensing data, Survey of India topographical sheets and field verification. The study area was divided into seven watersheds for the purpose of micro-level morphometric analysis. Based on these morphometric (linear, areal and relief) parameters of the watersheds, the groundwater potential zones were identified and the results substantiated with bore well or tube well data available for the terrain. The elongated shape, favorable drainage network, permeable geologic formation and low relief of Kumari (2A2A1) and Chaka (2A2A2) watershed makes them the promising groundwater potential zones of the Kumari River Basin. In addition, for better use and management of groundwater, we try to find artificial recharge structure and sites on the basis of groundwater potential map and groundwater fluctuation map.

Coastal areas of Bangladesh have been facing increasing salinity of surface water and groundwater. This study provides the approximate scope of the problem in a coastal area of southeastern Bangladesh by using less-accurate, but lower-cost salinity measuring devices that enable local people to assess the situation. Ten local women were employed to monitor 10 tube wells each on a weekly basis, from mid-February to mid-May, during the 2016 dry season. Geographical Information System and time series clustering were used to visualize the spatial distribution and seasonal change of the salinity levels. In addition, the tube well users were asked about the salt consumption in their daily diet. One-third of the monitored tube wells were found to contain more sodium than the tolerable level in terms of taste suggested by the World Health Organization. However, the mean salinity level across all monitored tube wells was much lower. The salinity level varied depending on the depth of the tube wells rather than their locations or altitudes, and those deeper than 200 m were likely to be salt free. The results of the diet survey showed that wealthier households tended to use more salt in their daily diets, but at the same time they tended to have deeper tube wells that are less likely to contain high levels of sodium.

Drinking water contaminated with arsenic poses serious threat to the human health. The present study was aimed for quality assessment of the groundwater of Khairpur Mir's in respect with arsenic and other elemental contamination like Fe, Cu, Co, and Ni. The presence of the trace elements in groundwater from different sources in the study area was measured by using atomic absorption spectroscopy. For arsenic analysis hydride generation technique (MHS-15) was used with detection limit of 0.02 µg l−1. Elevated level of arsenic was observed in most of the samples as compared to recommended value of World Health Organization (WHO) guidelines (10 µg l−1). However, levels of Fe, Cu, Co, and Ni in hand pump (HP) water samples was found in the range of 4–1610 µg l−1, 0–556 µg l−1, 0–230 µg l−1, and 0–700 µg l−1, respectively. Whereas in tube well (TW) water samples the observed values are 5–1620 µg l−1, 0–50 µg l−1, 4–110 µg l−1, and 0–360 µg l−1 for Fe, Cu, Co, and Ni, respectively. Significant difference...

The increasing concentration of nitrogen compounds in the groundwater is of a growing concern in terms of human health and groundwater quality. Although an excess of nitrogen compounds in the groundwater of the Kathmandu Valley has been reported, the seasonal variations of the fate of the nitrogen compounds and their relationships to the subsurface sediments are unknown. In this study, spatially distributed shallow dug well samples were collected during both the dry and wet seasons of 2016, and the nitrogen compound, chloride (Cl&minus, ), and iron (Fe2+) concentrations were analyzed. Two shallow dug wells and one deep tube well were monitored monthly for 2 years. Although NH4-N concentrations were similar in the clay-dominated areas during both seasons (1 and 0.9 mg-N/L), they were lower in the gravel-dominated areas during wet season (1.8 &gt, 0.6 mg-N/L). The NO3-N concentration differed depending upon the soil type which increased during the wet season (clay 4.9 &lt, 13.6 mg-N/L and gravel 2.5 &lt, 6.8 mg-N/L). The Fe2+ concentration, however, was low during the wet season (clay 2.7 &gt, 0.4 mg/L and gravel 2.8 &gt, 0.3 mg/L). Long-term analysis showed higher fluctuation of nitrogen compounds in the gravel-bearing areas than in the clay-bearing areas.