Assessment of borehole water quality in different areas of the Musahari block, Muzaffarpur

Borehole water is the most precious natural resource on Earth. It is widely used for drinking and other anthropogenic activities. The deteriorating quality of borehole water is becoming an important concern. This study focuses on the quality of borehole water in the Musahari Block of Muzaffarpur. Fifteen water samples were collected during the pre-monsoon season and analyzed for physicochemical parameters, including pH, TDS, TA, turbidity, EC, TH, Ca²⁺, Mg²⁺, Cl⁻, SO₄²⁻, NO₃⁻, As, Fe²⁺, F⁻, and a microbial parameter, namely total coliform, measured using standard procedures to assess its current quality status. The results obtained from the sample analysis were compared with the drinking water quality standards set by BIS and WHO. The analysis revealed elevated levels of physicochemical parameters such as TDS, alkalinity, turbidity, and iron, while some parameters fell below the acceptable range, underscoring the need for improved water treatment. Therefore, suitable mitigation measures should be adopted to enhance the water quality in the polluted area. The health risks associated with these parameters were also assessed.

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Introduction

Water is the most crucial resource for multitudinous life on this planet and is necessary for maintaining life on Earth. Approximately 97% of the planet's total water is saline, leaving only 3% as freshwater. However, of this 3%, merely 0.01% is easily accessible for human use. Groundwater, which makes up 99% of available freshwater, is the primary source of drinking water, with boreholes being a standard means of access [Azizullah et al., 2011] [5] . It is one of the most valuable sources of drinking water, extensively used in many regions worldwide. It serves various purposes, including domestic, agricultural, and industrial activities. Groundwater meets 42% of farming and 27% of industrial demands worldwide. At the same time, nearly one-third of the global population relies on it for drinking and domestic use [Nickson et al., 2005; Verma et al., 2020] [19,25] . More than 85% of drinking water supplies typically come from groundwater resources, and many urban and rural residents in India rely solely on groundwater. Growing populations, rapid economic expansion, and higher living standards have resulted in an ever-increasing demand for fresh water (Moussa et al., 2020; Shi et al., 2018) [3,26] . Groundwater plays a critical role in India, meeting 85% of rural drinking water needs, 62% of agricultural irrigation, and 45% of urban water demand (Verma et al., 2020) [24] . India's water crisis has worsened since 2017, when contaminated water caused 569,679 deaths (47.5% of the global 1.2 million fatalities). Recent estimates suggest over 650,000 annual deaths in 2023-24, with groundwater contamination now linked to approximately 60% of cases-primarily due to arsenic, fluoride, and industrial pollutants in states like Bihar, West Bengal, and Punjab (Ritchie & Roser, 2019; [Latest WHO/UNICEF/WRI Report, 2024]). Bihar, an agrarian state in Eastern India, lies within the Ganga-Meghna-Brahmaputra (GMB) basin, where groundwater serves as the primary source of drinking water, fulfilling over 80% of rural water needs. Of the 38 districts, 22 are severely impacted by arsenic contamination, exposing over half of the state's population to this critical health hazard [Kumar et al., 2021; Richards LA, 2020] [12,22] . Bihar's water-related death rate (11.97%) towers 56% above the national average (7.65%), exposing critical failures in groundwater protection (The Times of India, 2018).

In this new era of rapid development, population growth, and urbanization, groundwater pollution is being exacerbated by the expansion of industrial sectors, excessive use of fertilizers in irrigation, inadequate sewage systems, urban construction, and the disposal of human and animal waste. [Gao et al., 2020; Lapworth et al., 2012; Zhang et al., 2020; Adimalla et al., 2020] [23,18,23,18] . The recently tabled Bihar Economic Survey (2024-25) revealed alarming groundwater contamination across the state, with arsenic detected in 4,709 wards, fluoride in 3,789 wards, and excessive iron in 21,709 wards. Thus, consistent monitoring and testing of water samples are crucial to verify the safety and purity of groundwater.

Materials and Methods

Materials and Methods

Study site

Muzaffarpur is a major urban center in Bihar, serving as both the district headquarters of Muzaffarpur and the administrative seat of Tirhut Division. Situated along the Budhi Gandak River in northern Bihar, it ranks as the state's fourth most populous city. Muzaffarpur is located at a latitude of 26°07′North 85°24′E. This study primarily focuses on the drinking water quality index of Muzaffarpur, a district in Bihar. With approximately 473,000 urban and 4.33 million rural residents, the district's population depends largely on borehole water for drinking purposes. The present study focuses on the borehole water quality of Muzaffarpur. The study was conducted at 15 locations, encompassing residential, industrial, and slum areas. This study examined water quality in 15 boreholes across various locations: Bela (S1), Sadpura (S2), Mithanpura (S3), Motijheel (S4), Brahampura Daudpur (S5), Bela Industrial Area (S6), Bajrang Enterprises Bela Industrial Area (S7), Bela Cold Storage Phase 2 (S8), D3 Phase 2 (S9), B33 Phase 2 (S10), Sikandarpur (S11), Ganipur (S12), Brahampura (S13), Dadar Zero Mile (S14), and Daudpur Kothi (S15).

For the present study, borehole water samples were collected at one-month intervals during the pre-monsoon period (April to June 2024) from 15 different sampling sites, encompassing residential, industrial, and slum areas. Each borehole was pumped 5-10 minutes before collection to remove stagnant water and ensure representative sampling. The samples were then collected in pre-cleaned 1-liter polyethylene containers. Following standard protocols, the samples were immediately preserved in an icebox and transported to the laboratory within three hours of collection. Upon arrival, they were properly labelled, sealed, and stored at a constant temperature of 4 °C to maintain their integrity until analysis. The collected borehole water samples were analyzed for various Physico-chemical parameters, including pH, electrical conductivity (EC), total dissolved solids (TDS), turbidity, total hardness (TH), total alkalinity (TA), calcium (Ca²⁺), magnesium (Mg²⁺), chloride (Cl⁻), sulphate (SO₄²⁻), nitrate (NO₃⁻), arsenic (As), iron (Fe²⁺), and fluoride (F⁻), following standard methods (APHA). The borehole nozzle was sterilized for microbial analysis using cotton wool soaked in 70% ethanol. Before sampling, each borehole was pumped for 5-10 minutes to remove stagnant water. A 250 mL screw-capped sterile plastic bottle was then carefully uncapped, filled with the sample, and promptly recapped to prevent contamination.

Results and Discussion

The collected samples were analyzed to assess their compliance with drinking water standards set by the Bureau of Indian Standards (BIS) and the World Health Organization (WHO), evaluating both physicochemical and microbial parameters (Table 1) and the result is mentioned in table 2. Notably, total and fecal coliforms were absent in all tested samples, indicating no fecal contamination. [10] .

Area	pH	Turb.	EC	TDS	TH	Ca	Mg	Cl	Alk	Fe	SO4	NO3	F
S1	7.79	8.9	1265	820	496	146	32	137	522	2	40	10	0.2
S2	7.56	3.6	920	602	544	162	23	125	510	0.2	30	8	0.2
S3	7.62	4.2	1148	714	552	86	81	199	579	0.3	30	10	0.2
S4	7.81	9.2	1043	696	496	78	71	141	428	1.8	25	6	0.3
S5	7.79	4.1	1070	680	416	130	22	133	473	0.2	26	8	0.2
S6	7.52	2.7	887	576	456	40	85	87	468	0.2	20	5	0.3
S7	7.49	0.8	799	519	424	62	64	46	457	0.2	20	8	0.3
S8	6.98	0.9	1216	789	584	104	78	131	490	0.2	25	10	0.2
S9	7.13	0.5	633	412	352	54	52	50	372	0.3	18	15	0.4
S10	7.42	1.5	640	415	360	54	54	77	428	0.3	18	10	0.4
S11	7.4	4.9	874	568	400	99	37	185	408	1	20	5	0.3
S12	7.28	1.2	1110	720	260	62	25	115	567	0.3	30	5	0.2
S13	7.19	0.4	1346	875	432	128	27	187	563	0.3	25	10	0.3
S14	7.34	0.3	1139	740	428	75	58	81	547	0.2	20	5	0.2
S15	7.58	4.5	773	503	452	45	82	75	481	0.8	20	5	0.2

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Table 2Close ×

Value of different water quality parameter observed from

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Parameters	Acceptable /Desirable Limit (IS 10500-2012)	Permissible Limit in absence of alternate source IS	WHO Standard limit
pH	6.5-8.5	NR	no health based guideline value
Turbidity	1NTU	5NTU
Electrical Conductivity	750	2500
Total Dissolved Solid	500 mg/l	2000 mg/l	no health based guideline value
Total Hardness	200 mg/l	600 mg/l
Calcium	75 mg/l	200 mg/l
Magnesium	30 mg/l	100 mg/l
Chloride	250 mg/l	1000 mg/l
Alkalinity	200 mg/l	600 mg/l
Iron	0.3 mg/l	NR	no health based guideline value
Sulphate	200 mg/l	400 mg/l	no health based guideline value
Nitrate	45 mg/l	NR	50
Fluoride	1.0 mg/l	1.5 mg/l	1.5s
Arsenic	0.01 mg/l	NR	0.01
Total Coliform, CFU/100 ml	0	5

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Table 1Close ×

Standard values of different water parameters according to Bureau of Indian Standards (BIS) and the World Health Organization

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Electrical Conductivity

The study recorded electrical conductivity (EC) levels between 640-1346 μS/cm across all water samples, exceeding the BIS permissible limit of 1000 μS/cm at

Total dissolved solids

The study found TDS levels ranging from 503-875 mg/L in water samples, exceeding the BIS desirable limit of 500 mg/L at three sites (S1:820, S8:789, S13:875 mg/L). While most samples remained within acceptable/desirable limits, elevated TDS can affect water taste, promote pipe corrosion, and disrupt aquatic ecosystems. These results underscore the importance of regular monitoring to maintain water quality standards (Prasad et al., 2019) (Table 1).

Turbidity

Several sampling locations showed elevated turbidity levels (S1:8.9, S4:9.2), nearing the BIS permissible limit (1 NTU to 5 NTU). This indicates potential contamination from suspended particles, organic matter, or soil runoff, which can reduce water clarity, hinder disinfection, and promote bacterial growth (Table 2).

Total alkalinity

The water samples showed total alkalinity levels ranging from 372 to 579 mg/L, within the BIS limit of 600 mg/L but significantly above the desirable 200 mg/L limit. While not a health risk, such elevated alkalinity may impair water taste, promote scaling in plumbing systems, and reduce disinfection efficiency.

Total Hardness: The groundwater samples showed total hardness ranging from 260-584 mg/L, classified as 'acceptable' (<300 mg/L) to 'permissible' (300-600 mg/L) under BIS standards. These variations result from the natural dissolution of calcium/magnesium minerals during groundwater percolation. While posing no health risks, higher values near 600 mg/L may cause scaling, reduce soap efficiency, and affect water taste.

Table 3: Area with turbidity, TDS, Ca, Mg, Cl above the permissible limit and below the desirable limit

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Area with turbidity, TDS, Ca, Mg, Cl above the permissible limit and below the desirable limit

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Area

Turbidity NTU above the permissible/below the desirable limit TDS mg/l above the permissible limit, below the desirable limit Ca mg/l above the permissible limit/below the desirable limit Mg mg/l above the permissible limit/below the desirable limit Cl mg/l above the permissible limit /below the desirable limit S1 8.

Calcium

The groundwater samples showed calcium concentrations of 40-162 mg/L, which, while having no explicit BIS (IS 10500:2012) limit, translate to 100-405 mg/L as CaCO₃ hardness. Levels between 40-80 mg/L are nutritionally optimal, but higher concentrations (>100 mg/L) may cause scaling, reduce soap efficiency, and potentially increase kidney stone risk. These levels typically originate from natural sources like limestone dissolution and dolomite weathering (Table 1).

Iron

The study found iron concentrations of 0.2-2.0 mg/L in groundwater, with three sites (S1: 2.0 mg/L, S4: 1.8 mg/L, S11: 1.0 mg/L) exceeding the BIS limit (0.3 mg/L) by 3-6 times. While not acutely toxic, chronic exposure may cause hemochromatosis, digestive issues, and nutrient absorption problems. Excessive iron also promotes bacterial growth, reduces disinfection efficiency, and causes staining/clogging of infrastructure. The reddish-brown discoloration confirms iron contamination, requiring remedial measures at affected sites (Ansari & Hemke, 2013, Table 2).

Magnesium

The groundwater contained magnesium concentrations of 22-85 mg/L (equivalent to 91-350 mg/L as CaCO₃ hardness), within BIS limits. While nutritionally beneficial at 24-60 mg/L, higher levels (>60 mg/L) may cause temporary laxative effects and a bitter taste. These concentrations originate from the natural dissolution of dolomite and magnesium-rich minerals. Though compliant, values exceeding 70 mg/L warrant monitoring for potential scaling issues in water systems (Table 1).

Chloride

The study recorded chloride concentrations of 46-199 mg/L across all sampling sites, well below the permissible limit of 250-1000 mg/L (BIS standards). While anthropogenic sources like sewage leakage and waste dumping typically elevate chloride levels, the measured values indicate minimal contamination risk. Natural factors like soil porosity also contribute to chloride accumulation in groundwater, but current concentrations remain within safe drinking water parameters (Table 1).

Nitrate:

The analyzed groundwater samples exhibited nitrate concentrations ranging from 5 mg/L to 15 mg/L. According to the Bureau of Indian Standards (BIS IS 10500:2012) for drinking water quality, the permissible limit for nitrate (as NO₃) is set at 45 mg/L, with no relaxation allowed. All measured values in this study were well below this threshold, indicating compliance with national drinking water standards (Table 2).

Sulphate

Groundwater sulphates (18-40 mg/L) in all samples were well below BIS limits (200-400 originating from natural mineral dissolution and potential industrial infiltration. While low levels indicate minimal hardnesscontributing minerals, higher concentrations can affect water taste. The observed values reflect safe, naturally occurring sulphate levels per IS (Table 2).

Fluoride

The study found fluoride concentrations of 0.2-0.4 mg/L across all sites, below both BIS desirable (1.0 mg/L) and permissible (1.5 mg/L) limits. While optimal fluoride levels (1.0 mg/L) benefit dental health, the observed sub-optimal concentrations may increase fluorosis risk with long-term consumption as the primary intake source. Notably, excessive fluoride (>1. 2).

Table 4: Area with Fe, NO3, SO4, F, As, E. coli above the permissible limit and below the desirable limit

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Area with Fe, NO3, SO4, F, As, E. coli above the permissible limit and below the desirable limit

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Area

Fe mg/l above the permissible limit /below the desirable limit No3 mg/l above the permissible limit/below the desirable limit So4 mg/l above the permissible limit/below the desirable limit F mg/l above the permissible limit/below the desirable limit As above the permissible limit/below the desirable limit E coli above the permissible limit/below the

Acknowledgement

AcknowledgementsThe authors extend heartfelt thanks to the Regional Water Testing Laboratory, Muzaffarpur, for providing the necessary facilities and support to carry out this research. Financial supportThis research was self-funded.

Figures and tables from the paper

—	pH	Turb.NTU	E C	TDS mg/l	TH mg/l	Ca mg/l	Mg mg/l	Cl mg/l	Alkalinity mg/l	Fe mg/l	SO4 mg/l	NO3 mg/l	F mg/l
pH	1
Turb. NTU	0.79	1
EC	0.01	0.17	1
TDS mg/l	0.01	0.18	1.00	1
T H mg/l	0.21	0.36	0.37	0.36	1
Ca mg/l	0.21	0.31	0.57	0.57	0.45	1
Mg mg/l	-0.04	0.00	-0.23	-0.24	0.39	-0.65	1
Cl mg/l	0.14	0.37	0.66	0.64	0.36	0.58	-0.25	1
Alk	0.01	-0.11	0.75	0.73	0.20	0.32	-0.15	0.42	1
Fe	0.54	0.88	0.19	0.22	0.17	0.20	-0.03	0.25	-0.17	1
SO4	0.38	0.52	0.67	0.66	0.33	0.68	-0.40	0.50	0.58	0.44	1
NO3	-0.30	-0.20	-0.09	-0.10	0.10	0.19	-0.10	-0.05	-0.20	-0.12	0.09	1
F	-0.25	-0.22	-0.62	-0.61	-0.41	-0.43	0.09	-0.32	-0.71	-0.05	-0.61	0.40	1

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Correlation matrix of thirteen parameters of water quality

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