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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