Edited by: Prosun Bhattacharya, Royal Institute of Technology, Sweden
Reviewed by: Rachida Bouhlila, Higher National Engineering School of Tunis, Tunisia; Prafulla Kumar Sahoo, Central University of Punjab, India; Venkatramanan Senapathi, Alagappa University, India
This article was submitted to Environmental Water Quality, a section of the journal Frontiers in Water
†ORCID: Sarnam Singh
Rakesh Kumar
Prabhakar Sharma
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Groundwater quality due to geogenic factors, aggravated by anthropogenic activities, is a significant threat to human wellbeing and agricultural practices. This study aimed at mapping the spatial distribution of low and high groundwater-contaminated regions in the Sheikhpura district of Bihar for safe drinking and irrigation water availability. To account for spatial distribution, groundwater quality parameters, such as fluoride, iron, total dissolved solids, turbidity, and pH, were analyzed using integrated interpolation, geographical information systems, and regression analysis. A total of 206 dug wells and bore wells were analyzed for
Water, whether on the surface or underground, is the most essential and significant natural resource for sustaining life on Earth and for the sustainable growth of socioeconomic sectors such as irrigation and industrialization. Water, in each form, is an essential component of hydro-geo-ecological and various other metabolic, physiological, and ecological processes of living beings. The “resourcism” and unethical human activities in the Earth's biosphere–hydrosphere–geosphere have created a global water imbalance and crisis which threatens the life of the billion individuals and numerous natural ecosystems (Mekonnen and Hoekstra,
Groundwater aquifers are the primary source of water supply in rural and urban areas, mainly in the arid and semiarid regions worldwide (Dash et al.,
Groundwater systems have their unique chemistry and characteristics at each location and depend on various climatic changes, precipitation, surface water, and recharge parameters. Water quality depends mainly on underlying rock's geochemical and lithological composition and subsurface factors (Magesh and Chandrasekar,
India's dependency on groundwater for crop irrigation and drinking water is very high (Shankar et al.,
Fluoride (F) contamination is a severe problem in groundwater across India and the world (Changmai et al.,
In Bihar, among 38 districts, 13 districts are located beside the Gangetic river are partly impaired by pollution due to the high concentration of arsenic (As >0.05 mg/l), affecting 1,590 habitations (Singh et al.,
Geostatistics has been globally applied as a decision-making tool for groundwater level (Knotters and Bierkens,
This study aims for adequate information on spatial distribution of groundwater quality for long-term assessment and implementation of groundwater management strategies for irrigation and potable water supply. Therefore, this study proposed spatial mapping and distribution of groundwater quality parameters, such as fluoride, iron, pH, and TDS, using integrated interpolation techniques, geographical information systems, and regression analysis into low and high groundwater contaminated regions in the Sheikhpura district of Bihar for safe drinking and irrigation water supply. Geospatial pattern analysis of different quality parameters is essential for management and monitoring agencies such as Central and State Pollution Control Boards, farmers, agricultural research institutes, the Government of Bihar, and India to implement schemes and policy in different regions.
The study area was Sheikhpura, a district in South Bihar, India, which lies between 24°45′ and 25°45′ North and 85°45′ and 86°45′ East longitude. The district has six blocks and 360 villages, extending over 609.51 km2 in size (
Village map of Sheikhpura district indicates groundwater sample locations (
Soil maps
With a sampling intensity of 10%, 36 villages encompassing all the blocks were randomly selected based on strata of location, population, block, and village size (big, medium, and small). Out of 2,000 bore wells in the area, 206 bore wells were sampled and analyzed. The data on F, Fe, TDS, turbidity, and pH collected by the Ministry of Drinking Water and Sanitation, Government of India, in 2017 under the National Rural Drinking Water Programme were used in this study. The geotagging of these wells was done using the Garmin eTrex Legend navigation system. We prepared a geospatial database of soil types and subgroups (ICAR,
The geospatial approaches such as Kriging and IDW interpolate the spatial variability of point attributes and predict for an unobserved location using nearby known attributes (Rakhmatullaev et al.,
Parameterization of groundwater quality assessment.
Fluoride (F) | 4 | F <1 | Very good | 3 | <1.5 mg/l | <1.5 mg/l |
1 ≤ F ≤ 1.5 | Moderate | 2 | ||||
F > 1.5 | Very poor | 1 | ||||
Iron (Fe) | 3 | Fe <0.07 | Very good | 3 | <0.1 mg/l | <0.3 mg/l |
0.07 ≤ Fe ≤ 0.1 | Moderate | 2 | ||||
Fe > 0.1 | Very poor | 1 | ||||
TDS | 2 | TDS > 500 | Very good | 3 | 300–1,700 mg/l | 2,000 mg/l |
500 ≤ TDS ≤ 700 | Moderate | 2 | ||||
pH | 1 | 7.11 ≤ pH ≤ 7.51 | Very good | 3 | 6.5–9.5 | 6.5–8.5 |
In this study, groundwater quality parameter limits followed the standards outlined by WHO (
Geospatial maps of groundwater quality:
Iron is a vital element and occurs naturally in water. The geogenic source of iron in groundwater is due to the underlying quartzite rocks of Sheikhpura. A similar geogenic source of iron in groundwater is reported in the literature (Rao,
The pH determines the acidity and alkalinity of groundwater as a significant water quality parameter. The permissible limit of pH ranged from 6.5 to 9.5 as per WHO recommendations (WHO,
TDS characterizes the total concentration of dissolved substances in groundwater, an important parameter to measure drinking water/groundwater quality. TDS indicate fully dissolved minerals, such as calcium, chlorides, carbonates, bicarbonates, magnesium, silica, and sodium, in groundwater (Anbazhagan and Nair,
Seventeen observational data points were used to validate the results of Kriging interpolation. The actual observations were evaluated concerning the predicted values. The goodness of fit for an actual concentration of contaminants indicated that the coefficient of determination (
Model accuracy assessment between observed and predicted groundwater quality parameters:
Relationship between observed vis-à-vis predicted groundwater quality.
Fluoride | 0.36–2.12 mg/l | 0.37–2.32 mg/l | 0.960 |
Iron | 0.00–0.3 mg/l | 0.06–0.33 mg/l | 0.905 |
TDS | 251–700 mg/l | 269–712 mg/l | 0.910 |
pH | 7.02–7.33 | 7.11–7.38 | 0.906 |
Characterization for groundwater quality mapping based on class interval and weights to different layers of F, Fe, TDS, and pH per their significance is shown in a map (
Potential groundwater quality map for planning and management of groundwater harvesting and supply.
Groundwater is vulnerable to contamination under different soil types (Li et al.,
Summarized relationship between soil types and groundwater quality.
Greenish clay caliche oxidized, pedocal soil | Fine vertic ochraqualfs | 0.37–2.32 | 7.04–7.26 | 269–507 | 0.13–0.22 |
Sand silt and clay unoxidised | Coarse loamy typic ustifiuvents | 0.77–1.15 | 7.27–7.38 | 406–560 | 0.19–0.30 |
Silt and clay of variegated colors | Fine aeric ochraqualfs | 0.37–0.76 | 7.18–7.29 | 406–560 | 0.19–0.22 |
- | Fine vertic ustochrepts | 0.37–1.54 | 7.18–7.38 | 456–712 | 0.00–0.30 |
Groundwater contaminant concentrations were randomly distributed among different soil types in the area. There is no noticeable, quantifiable, and significant relationship between soil types and groundwater contaminants. A similar study by Sheehan et al. (
Integrated interpolation techniques, geostatistical systems, and regression analysis have proved efficient decision-making tools for groundwater quality analysis, monitoring, and management. In this study, the spatial groundwater quality parameters, such as F, Fe, TDS, and pH, were analyzed across six blocks of the Sheikhpura district of Bihar. Groundwater in Sheikhpura, Arari, and Chewara blocks were contaminated with high fluoride concentrations up to 2.42 mg/l. In addition, iron has also spread with more than the WHO permissible limit (>0.1 mg/l) across all six blocks. Reasons behind the enrichment of fluoride and iron in the groundwater of the Sheikhpura district of Bihar are the underlying geological features composed of quartzites, phyllite, and schist rocks. Besides this, TDS and pH were found under the allowable limit across the district. The spatial analysis of different parameters is conducted based on the Kriging method by estimating unobserved locations relating to the known values. This study also attempted to establish the relationship between soil types and groundwater contaminants; however, no statistical correlation was found for each groundwater quality parameter considered for spatial mapping in the Sheikhpura district. The final groundwater quality map highlighted the area having groundwater quality from “poor” to “very good” across the district. In the interpolated map, the overall groundwater quality of the Arari, Chewara, and Sheikhpura blocks is not appropriate; thus, aquifer quality is relatively low and not acceptable for drinking and irrigation purposes. Thus, spatial mapping of groundwater quality will help policymakers to better operate and manage the groundwater resources through detecting pollutants, demand–supply gap, etc. Overall, proper utility and management of groundwater through canals, channels, and underground movement from safe to affected blocks/zones are recommended for drinking and agricultural purposes to avoid carcinogenic diseases among the population in the future.
Publicly available datasets were analyzed in this study. This data can be found at: All the primary groundwater quality data were obtained from the website of Ministry of Drinking Water and Sanitation, Government of India, surveyed in 2017 under the National Rural Drinking Water Programme and has been duly acknowledged. Map of soil types and soil subgroups published by the National Bureau of Soil Survey and Land Use Planning (ICAR 1998), Nagpur, India. were used.
RiK: conceptualization, sampling strategy, fieldwork, GIS database creation and analysis, and writing of the first draft of the manuscript. SS: conceptualization, sampling strategy, methodology, GIS analysis supervision, review of results, and editing of the manuscript. RaK: support in GIS analysis, writing, reviewing, and editing of the manuscript. PS: initial conceptualization, review, and editing of the manuscript. All authors contributed to the article and approved the submitted version.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.
The authors would like to record their gratitude to SEES lab, Nalanda University for scientific facilities and also like to express their gratitude to the National Rural Drinking Water Programme, Ministry of Drinking Water and Sanitation, Government of India for allowing access to the data on their website. We want to thank Dr. Dharmendra Singh, Assistant Scientist (Environment/Ecology) Haryana Space Applications Centre, Hissar for his timely help during the analysis.
The Supplementary Material for this article can be found online at: