A pragmatic approach of hydrochemical and irrigation indices of groundwater quality of district Ballia, U.P. India

The prime source of water for drinking, agriculture, and domestic use is groundwater. Higher chemical ingredient concentrations have a detrimental effect on the environment and general public health (Anderson 2014; Saha et al. 2019).

Groundwater, the purest form of natural water currently available, serves the demands of people living in rural and semi-urban areas. But when human communities and industries grow, it creates bioenvironmental issues that endanger the resources of the land, water, and air (Milovanovic 2007; Das & Nag 2015). Today, groundwater serves as the primary source of water for the domestic, commercial, and agricultural sectors in many countries. Many anthropogenic activities can pollute groundwater, including fertilizer spills, natural erosion, and saltwater intrusion. The current study aims to assess the groundwater's quality and determine its suitability for various uses. The investigation will also show where the groundwater's chemical components come from (Saha et al. 2019).

The kind of bedrock, geology, climate, geography, atmospheric precipitation, soils, the quality of recharged water, as well as agricultural, industrial operations and anthropogenic pollution sources, all have an impact on groundwater quality. In addition, biological activities, weathering, dissolution, precipitation, ion exchange, and other subsurface geochemical phenomena may affect groundwater quality (Todd 1980; Sakram et al. 2013; Ravikumar et al. 2015).

In recent years, several cities in developing countries have witnessed substantial demographic growth as a result of the eviction of rural residents. As a result of urbanization and unregulated population growth, the geography and drainage system of the area have changed, and this has a direct impact on the quality and amount of groundwater (Vasanthavigar et al. 2010; Das & Nag 2015).

Human health and plant growth are negatively impacted by poor water quality (Nag & Ghosh 2013). In recent years, there has been a lot of interest in the role that water quality plays in human health. Around 80% of all infections in developing nations like India in particular are associated with unsanitary conditions and inadequate water quality (Limbachiya et al. 2011; Pazand & Hezarkhani 2013; Vincy et al. 2015). Enough good-quality water must be available for irrigation. An index that takes into account the amount and level of dissolved components in the water could be useful for determining if the water is acceptable for agricultural use (Majdoub et al. 2012; Agoubi et al. 2013). Depending on the types of minerals present and how they affect the soil and plants, groundwater may be suitable for irrigation (Singh et al. 2009; Aziane et al. 2020).

An effective method for determining if groundwater is suitable is hydrochemical analysis. The physical and chemical characteristics are both taken into account. Hydrogen ion concentration (pH), specific electrical conductance (EC), total dissolved solids (TDS), and all main cations and anions are among the chemical factors taken into account (Saha et al. 2019).

As a result of the widespread use of groundwater resources in industry, agriculture, and drinking, the study's objective is to examine the quality of the region's groundwater. For residential and other uses, it is crucial to determine the area's groundwater quality. The purpose of this study is to assess the local groundwater's suitability for irrigation using hydrochemical techniques.

The groundwater of Ballia district is highly contaminated with ions; the majority of the population belongs to farmers and micro-business owners who cannot afford filtered water and are not aware of the contamination of the groundwater. The research article provides information about the quality of water to local authorities to provide qualitative water to communities.

In the northern and southern boundaries of a block of area flowing Ganga and Ghaghara Rivers. The area is divided into two major plains first, older alluvium which is affected by flood, and other newer alluvium which is free from flood.

Growing crops is the prime source of income for the majority of the population so crops are grown throughout the year. The Kharif crop grows from July to October in the monsoon season, the Rabi crop grows from October to March, and the Jayad crop grows from March to June.

About 88% of the study region's total irrigated land is used for agricultural growth. In the research area, tubewells and canals are the primary irrigation methods. The Doharighat Pumping Canal and the Surha Taal Pumping Canal System are two major irrigation canals in the study region, which are largely developed toward the northwest.

From the various blocks of the Ballia District, hand pumps (India Marka-II and Shallow deep) were used to gather a total of 16 groundwater samples. The sample was taken using polyethylene bottles that had been well cleaned and rinsed. Before the collection of the water sample, the hand pump was flushed with 30–35 L of water for fresh and undisturbed water samples. Two sets of water samples were collected from each location. 1% of HNO₃ was added to the first set of bottles to preserve the trace metals and stored to refrigerate. The second set of the bottle was prepared without preservatives for cations and anions analysis of the water sample. Within 1 week, all the collected samples were analyzed. The sample's pH values were ascertained using the APHA (American Public Health Association) Electrode method. The APHA 2510B method was used to test resistivity and electrical conductivity. TDS was measured using an electrometric probe, and turbidity was assessed using the APHA 2130B method. Thermo Scientific's ion chromatograph (Model: DIONEX Aquion) using Dionex Ion Pac AS23, was used to analyze the substances chloride, fluoride, and sulfate. Calcium, potassium, magnesium, sodium, and iron were analyzed by Thermo Scientific iCAP RQ, ICP MS APHA 3125 (Verma & Chaurasia 2023). The collected data analysis for Durov, Gibbs, Stiff, and Wilcox plots was prepared using the software Origin (2019b) and for Stiff map Origin (2021).

In addition to cations and anions, the groundwater samples also include many additional ions. Table 1 lists these ions' elements along with their maximum, minimum, mean, and coefficient of variation of concentration values. The mean value of pH is 7.293 and ranges from 6.61 to 7.746, which indicates the neutral nature of groundwater pH does not lead to the dissolution of heavy metals in the groundwater of the study area. The conductivity of the study area is found at a higher range of 737–2,752 μS/cm and the mean value is 1,529.938 μS/cm. Although the long-range variance is caused by geochemical processes such as ion exchange, silicate weathering, rock–water interaction, and oxidation process, the higher range of conductivity may induce many gastro-related problems (Ramesh 2008; Annapoorna & Janardhana 2015). The resistivity of the water sample in the study area is short range, mean value of 0.8239 kΏ/cm and ranges from 0.384 to 1.359 kΏ/cm. The second largest range variation found on TDS ranges from 369 to 1,378 ppm and its mean value is 766.125 ppm, although it suggests that groundwater aquifers have a decreasing nature (Islam et al. 2017). The turbidity value of groundwater ranges from 0.33 to 3.42 nephelometric turbidity unit (NTU) and the mean value is 0.9738 NTU. The groundwater of the study area is not very turbid except few stations and may be used for irrigation purposes. The salinity ranges from 0.37 to 2.87 ppm and its mean value is 1.0263 ppm. The range of salinity indicates the saltwater intrusion in the groundwater aquifer and it may be due to salt-rich rock in the aquifer. Mg, Na, K, Ca, and Fe are the sample's principal cations, and HCO₃, SO₄, NO₃, Cl, CO₃, and NO₃ are its significant anions, in that order chronologically. Na concentration in groundwater ranges from 0 to 57.97 ppm and the mean value is 16.5946 ppm. Excess Na may cause congenial diseases, hypertension, and nervous and kidney disorders although damages the sensitive plant and crop roots (Ramesh & Elango 2011; Annapoorna & Janardhana 2015). A higher value of Na is due to chemical weathering, marine, ores, geological interaction, and overexploitation of groundwater resources (Sidle et al. 2000; Laurent et al. 2010; Yidana & Yidana 2010; Annapoorna & Janardhana 2015). Mg concentration in groundwater ranges from 0 to 64.61 ppm and the mean value is 18.8358 ppm. Mg is the higher value in the group of cations of groundwater of the study area and the major source of Mg in groundwater is due to CaCO₃, MgCO₃, CaSO₄ minerals, agricultural waste, and groundwater–geological interaction (Sidle et al. 2000; Laurent et al. 2010; Nosrati & Van Den Eeckhaut 2012; Annapoorna & Janardhana 2015).

The concentration of K ranges from 0.5 to 11.97 ppm and mean value of 3.7531. The major source of K in groundwater is due to rock minerals, atmospheric deposition, bacterial oxidation, and fertilizer (Sidle et al. 2000; Otero et al. 2007; Man et al. 2014). Ca concentration in the study area ranges from 0 to 9.8 ppm and the mean value is 3.1056 ppm. The main source of Ca is derived from the same source of as that for Mg. The concentration of Fe ranges from 0 to 0.06 ppm a mean value of 0.0175 ppm. The main source of Fe is magmatic rock, hematite, magnetite, ores, and anthropogenic source (Lasaga 1984; Yang 1998; Sidle et al. 2000; Otero et al. 2007). Hardness value ranges from 164 to 691 ppm and the mean value is 393.125 ppm. Hardness in groundwater is due to the presence of Ca and Mg ions. The concentration of F in a groundwater sample ranges from 0 to 2.6429 ppm, with a mean value of 1.5869 ppm at some sites, this amount exceeds the allowable limit. The main sources of F are weathered rock, fluoride-rich rock, irrigation processes, logged groundwater, minerals, and ores (Lasaga 1984; Datta et al. 1996; Yang 1998; Srinivasamoorthy et al. 2008). The concentration of Cl ranges from 13.98 to 298.03 ppm and the mean value is 117.6638 ppm. The higher level of Cl causes odor and, salty taste and may raise high blood pressure and heart problems. The higher value of Cl is due to the leaching of soil, and domestic waste (Srinivasamoorthy et al. 2008; Annapoorna & Janardhana 2015).

The concentration level of NO₂ ranges from 0 to 4.8124 ppm to a mean value of 1.6599 ppm. The concentration of NO₃ ranges from 0.32 to 342.96 ppm and the mean value is 124.4433 ppm. The main source of NO₃ is natural and anthropogenic activity, decomposition of organic matter, and fertilizer (Karnath 1987; Annapoorna & Janardhana 2015; Verma & Chaurasia 2023). The concentration of SO₄ ranges from 6.26 to 418.52 ppm and the mean value is 135.6921 ppm. The SO₄ in groundwater is due to sedimentary rocks, anthropogenic activity, agricultural waste, and ores (Kim et al. 2005; Laurent et al. 2010; Nosrati & Van Den Eeckhaut 2012; Verma & Chaurasia 2023).

The concentration of Br ranges from 0 to 2.7986 ppm and the mean value is 0.8407 ppm. HCO₃ is the dominant anion and its concentration ranges from 131 to 290 ppm with a mean value of 203.25 ppm. The main source of HCO₃ is due to rocks, groundwater-geological interaction, minerals, and agricultural waste (Sidle et al. 2000; Laurent et al. 2010; Nosrati & Van Den Eeckhaut 2012; García & Borgnino 2015). The concentration of CO₃ ranges from 0 to 18.9 ppm and the mean value is 4.9187 ppm. The main source of CO₃ is due to rocks and marine sources (Lasaga 1984; Yang 1998; Man et al. 2014; Rusydi et al. 2021; Verma & Chaurasia 2023).

The water quality index (WQI) is a measure used to assess the overall quality of water. It helps in evaluating the suitability of water for different purposes (Shankar & Sanjeev 2008). According to WQI, (Table 2), the groundwater quality of the Hanumanganj, Bansdih, Beruarwari, Maniyar, and Murlichhapra blocks of the Ballia district is ‘unsuitable for drinking’. The groundwater quality of Dubahar, Rasada, Chilkahar, Siar, and Sohaon blocks is ‘poor’, Belhari, Garwar, Bairia, Nagra and Navanagar block is ‘good’ and only Revati blocks show ‘excellent’.

According to Stufzand's classification, the water of Revati and Dubahar are classified with code ‘a’ which has values of Cl 0.3944 and 0.7845 meq/L having type oligohaline. Five other samples of Beruawari (4.90 meq/L), MurliChhapra (6.88 meq/L), Sohaon (8.10 meq/L), Hanumanganj (8.41 meq/L), Bansdih (8.31 meq/L) found in fresh brackish with code ‘b’ most of the groundwater samples of (nine blocks) fall in the freshwater category with code ‘B’ (Table 3). Based on the classification the dominating elements are Cl, Na, and HCO₃ of water subtype.

The classification levels according to the concentration of HCO₃ (meq/L), Sohaon (4.14 meq/L), Maniyar (4.52 meq/L), Beruawari (4.75 meq/L), and Hanumanganj (4.19 meq/L) moderately high are classified with code ‘5’ whereas 12 samples having values between 2.4 meq/L are classified with code ‘4’ which showing the alkalinity of water having moderate type. Based on the analysis, the result of the classification level of HCO₃ of a water sample is classified with code ‘5 to 4’ which shows moderately high to moderate type water.

The classes of most of the samples are found in the category of surplus of (Na + K + Mg). Only two samples Bansdih and Sohaon have the equilibrium of (Na + K + Mg) with code ‘0’.

A Gibbs plot showing the leading intervention developed from rock–water interaction and partial intervention from evaporation. Rock–water interaction and evaporation indicate the weathering of silicates, evaporate dissolution, carbonate dissolution, anthropogenic activities, etc., shown in other studies (Islam et al. 2017; Wang et al. 2023).

According to the analysis of the Durov, Gibbs, and Stiff plots, the quality of the groundwater sample is found calcareous. This study reveals that the mineralization of the aquifer, weathering of silicates, evaporate dissolution, carbonate dissolution, anthropogenic activities, etc. A study of the Durov plot shows that different ions in groundwater media have a geogenic origin in which sodium and chloride ions are found abundantly. The study of the Gibbs diagram shows that a high value of the concentration of ions in water leads to higher values of EC, TDS, hardness, etc. The results from the Gibbs diagram open a path for the Stiff plot's study which demonstrates the consensus between the findings of the Gibbs and Stiff plots eventually. Further statistical results like SAR, RSC, KI, PI, Na%, and EC reveal the moderately safe and comparatively good quality of water which illustrates that the groundwater of the study area could be found fair for irrigation purposes with minor precautions. In addition, the WQI results also reveal that the prominent groundwater pollution and the majority of groundwater samples are not fit for drinking purposes. This study shows that continuous monitoring might reduce the overexploitation of groundwater in the study area. Further studies about the chemical and biological mechanisms of the current findings will be a great source of interest to the researchers in the field of water quality and their possible effects on human and nature; the research paper offers information regarding the quality of the water to help local authorities supply communities with high-quality water. For many scholars studying hydrogeochemistry and hydrogeology, the current publication provides alternative ideas like the development of new hydrochemical indices, climate change impact on irrigation indices, urban agriculture, and comparative analysis of existing indices.

The authors acknowledge the assistance of STIC (Sophisticated Analytical Instruments Facility), Cochin India, and BSIP (Birbal Sahni Institute of Palaeosciences), Lucknow, India, in providing numerous chromatographic and analytical researches. The authors also acknowledge Dr Iffat Ameen of Deen Dayal Upadhyay Gorakhpur University for her suggestions and insightful comments. Additionally, we appreciate Madan Mohan Malaviya University of Technology in Gorakhpur, India, for providing the essential laboratory and library resources.

This research work is not supported by any funding agency.

Data cannot be made publicly available; readers should contact the corresponding author for details.

The authors declare there is no conflict.