Geofluids

Research Article

Chemical Evolution Process and Quality Assessment of Seepage Groundwater in Tunnel Crossing Gas-Bearing Coal Seams

Table 5

Statistics of groundwater water chemical parameters (mg/L).


	Group I			Group II			Group III			Group IV
	Mean	Min	Max	Mean	Min	Max	Mean	Min	Max	Mean	Min	Max

pH	8.32	7.98	8.61	8.45	8.27	8.60	8.69	8.56	8.95	8.38	8.08	8.62
EC	332.38	138.00	601.00	254.25	188.00	328.00	299.33	211.00	516.00	229.67	31.00	282.00
TDS	165.88	69.00	300.00	126.50	94.00	163.00	148.67	106.00	253.00	114.50	16.00	140.00
HCO₃^-	117.95	0.00	190.69	101.28	3.43	183.06	75.64	0.00	179.25	107.53	19.07	163.99
SO₄^2-	53.90	0.42	122.56	37.50	8.29	69.41	83.53	70.27	114.79	26.23	5.77	53.78
Cl^-	1.32	0.35	2.76	1.51	0.69	1.94	1.70	1.43	2.20	0.91	0.18	1.82
NO₃^-	6.26	1.15	30.20	3.50	0.28	6.67	4.33	3.00	5.26	2.84	0.68	5.07
F^-	0.41	0.22	0.74	0.65	0.24	1.53	0.47	0.20	0.60	0.21	0.11	0.33
Ca²⁺	34.31	1.56	69.31	21.64	0.00	46.81	28.32	2.90	64.27	38.12	0.19	57.55
Mg²⁺	22.18	0.00	69.20	5.21	3.36	7.07	3.55	0.00	5.82	8.89	0.00	23.86
Na⁺	18.58	1.15	40.20	27.62	6.55	38.74	25.12	14.80	32.59	6.53	0.23	11.69
K⁺	8.29	0.82	45.42	11.10	2.02	29.72	18.98	4.34	47.66	3.34	0.13	7.20
NH₄⁺	1.04	0.00	6.63	0.16	0.00	0.48	0.04	0.00	0.22	0.06	0.00	0.24
Fe	0.36	0.00	0.78	0.23	0.00	0.59	0.32	0.08	0.74	0.28	0.00	0.53
Al	0.03	0.00	0.11	0.07	0.00	0.23	0.17	0.02	0.76	0.03	0.00	0.08

Note: pH is dimensionless, conductivity unit is s-cm^-1, and other units are mg/L.