Geochemistry and assessment of groundwater resource in coastal arid region aquifer (Dahab delta, South Sinai, Egypt)

Samy, Amira; Eissa, Mustafa; Shahen, Seham; Said, Moustafa M.; Abou Shahaba, Rabab M.

doi:10.1186/s43088-023-00393-6

Beni-Suef University Journal of Basic and Applied Sciences

Table 1 Chemical analyses of salinity, major ions, and minor elements (mg/L) of the Quaternary aquifer at Dahab Area

From: Geochemistry and assessment of groundwater resource in coastal arid region aquifer (Dahab delta, South Sinai, Egypt)

Variables	Mean	Median	Min	Q1	Q3	Max
Upstream watershed groundwater (8 samples: 1, 31–37 and 44)
pH	7.4	7.40	7.10	7.30	7.58	7.80
EC µmhos/cm	1764	1314	641	654	1873	5790
Salinity (TDS) (mg/l)	1065	684	339	362	1138	3842
Ca²⁺	112	87	47	50	114	47
Mg²⁺	39	21	5	11	48	152
Na⁺	178	113	52	61	181	660
K⁺	6	7	3	3	8	10
Alkalinity	100	107	49	69	122	140
SO₄²⁻	464	253	101	116	549	1809
Cl⁻	217	150	58	62	208	833
Si	10.1	9.52	7.69	8.69	10.58	15.59
Sr	2.2	1.18	0.58	0.81	1.68	9.57
B	0.6	0.58	0.16	0.42	0.69	1.27
Br	56.9	32	8.80	21	68	150
Downstream delta groundwater (31 samples)
pH	7.8	7.70	7.00	7.50	8.00	8.60
EC µmhos/cm	17,287	7290	1793	5820	9190	78,100
Salinity (TDS) (mg/l)	10,757	3846	895	3221	4793	53,216
Ca²⁺	420	416	67	297	520	874
Mg²⁺	264	63	5	38	81	1453
Na⁺	3156	840	250	680	1300	17,600
K⁺	107	21	9	14	45	600
Alkalinity	100	85	49	67	128	201
SO₄²⁻	1689	645	179	515	1040	7266
Cl⁻	5062	1812	333	1333	2207	25,906
Si	17.3	7.34	7.77	13.45	21.04	34.82
Sr	7.5	7.46	0.89	5.08	9.54	16.79
B	2.8	1.98	1.09	1.43	3.19	9.14
Br	46.8	31	8.80	21	48	144
Reverse osmosis reject brine water (4 samples: R1 to R4)
pH	8.2	8.00	7.50	7.65	8.90	9.40
EC µmhos/cm	57,068	67,000	742	30,271	78,900	82,800
Salinity (TDS) (mg/l)	38,524	44,253	341	20,178	54,006	58,442
Ca²⁺	567	562	8	264	874	8
Mg²⁺	1289	1681	0	632	1750	1820
Na⁺	11,863	12,800	116	6358	16,900	18,400
K⁺	441	600	6	203	600	600
Alkalinity	74	76	0	31	120	140
SO₄²⁻	3479	1356	20	47	6428	9486
Cl⁻	10,298.7	439.80	46.30	174.93	24,823.40	27,489.00
Si	9.7	7.34	3.17	3.25	15.53	24.33
Sr	5.5	1.56	0.03	0.12	12.29	13.14
B	6.3	7.75	1.40	2.97	8.21	8.34
Br	80.7	13	1.67	5	156	240
Water extract (10 samples: Ex1–Ex10)
pH	8.3	8.25	7.30	7.98	8.75	9.10
EC µmhos/cm	1190	673	311	359	2027	3750
Salinity (TDS)	816	412	187	219	1456	2676
Ca²⁺	134	24	11	13	34	11
Mg²⁺	11	6	3	3	16	45
Na⁺	95	65	16	33	106	400
K⁺	25	18	8	13	40	52
Alkalinity	51	49	31	31	56	104
SO₄²⁻	404	177	47	66	822	1356
Cl⁻	122	86	37	44	139	440
Si	3.6	3.51	1.52	2.75	4.72	5.95
Sr	0.6	0.38	0.10	0.17	1.25	1.56
B	< 0.0004	< 0.0004	< 0.0004	< 0.0004	< 0.0004	< 0.0004
Br	4.9	3.75	1.33	1.79	8.63	9.50

Q1, the lower quartile, or first quartile is the value under which 25% of data points are found when they are arranged in increasing order; Q3, the upper quartile, or third quartile is the value under which 75% of data points are found when arranged in increasing order

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