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Table 2 Statistical summary of the physicochemical parameters of groundwater samples collected from the study area

From: Investigating aquifer contamination and groundwater quality in eastern Terai region of Nepal

Parameters

Range

Mean

Standard deviation

Median

WHO guidelines

NDWQS guidelines

Samples not within limit

Number

%

Groundwater (N = 175)

 pH

5.00–8.59

6.953

0.595

6.99

6.5–8.5

6.5–8.5

34

19.43

 Temp (°C)

17.0–35.9

27.721

4.606

28.5

–

–

–

–

 EC (µS/cm)

14.8–1898.0

445.500

264.949

436

–

1500

(1)

(0.57)

 Turbidity (NTU)

0.00–149.00

12.729

21.756

3.29

5

5

78

44.57

 Color (Hazen)

0.01–4.10

0.219

0.461

0.11

15

5

0

0

 TDS (mg/L)

7.50–949.00

231.034

128.581

224

1000

1000

0

0

 F− (mg/L)

0.02–1.10

0.235

0.216

0.16

1.5

0.5–1.5

0 (152)

0 (86.86)

 NH3 (mg/L)

0.05–3.36

0.477

0.440

0.38

1.5

1.5

6

3.43

 NO3 (mg/L)

0.05–3.38

0.266

0.569

0.05

50

50

0

0

 Cl− (mg/L)

0.50–161.8

17.011

29.464

3.5

250

250

0

0

 TH (mg/L)

1.11–510.00

191.644

87.865

205.35

–

500

(1)

(0.57)

 CH (mg/L)

1.00–412.62

118.856

66.097

116.23

–

–

–

–

 TA (mg/L)

2.36–512.40

197.678

89.929

213.06

500

–

1

0.57

 Fe (mg/L)

0.05–23.10

1.836

3.642

0.46

0.3

0.3

107

61.14

 Mn (mg/L)

0.05–3.10

0.367

0.486

0.21

–

0.2

(88)

(50.28)

 As (mg/L)

0.005–.050

0.005

0.003

0.005

0.01

0.05

1 (0)

0.57 (0)

 Ca2+ (mg/L)

0.00–165.05

45.137

26.218

41.281

–

200

0

0

 Mg2+ (mg/L)

0.00–61.49

18.523

12.632

16.28

–

–

–

–

  1. Numeric values within bracket represent samples number and percentage of samples not within limit as per NDWQS guidelines while those outside are as per WHO
  2. EC electrical conductivity, TDS total dissolved solutes, TH total hardness, CH calcium hardness, TA total alkalinity, WHO World Health Organization, NDWQS Nepal Drinking Water Quality Standard