1 Introduction
2 Study Area
2.1 Arabian Shield
2.2 Arabian Shelf
3 Data and Methods
3.1 Groundwater Depletion from GRACE
3.2 Ionic Composition of Cations and Anions of Groundwater Samples
Measurement | Method | Quantification |
---|---|---|
Ca, Mg | Flam atomic absorption | 0.1 mg/l |
Na, K | Flam photometry | 0.1 mg/l |
HCO3 | Acid titration with colored indicator | 0.1 mg/l |
Cl | Specific electrode | 0.05 mg/l |
SO4 | Nephelometry | 0.05 mg/l |
NO3 | Colorimetry | 0.05 mg/l |
Trace elements | Furnace atomic absorption | 0.1–1 μg/l |
3.3 Radioactive Analysis
4 Results
4.1 GWS from GRACE
4.2 Ionic Composition of Arabian Shelf and Arabian Shield
Sample_ID | Province | long | Lat | Temp | Well use | Depth (meter) | PH | Conductivity (µs/cm) | T.D.S (mg/L) | Ca++ (mg/L) | Mg++ (mg/L) | Total alkalinity (mg/L) | Chlorides (mg/L) | Sulfate SO4− | NO3− (mg/L) | Gross α (Bq/L) | Gross β (Bq/L) |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
SQ1 | Tabuk | 36.5 | 28.4 | 32.0 | DW | 607.0 | 7.0 | 888.0 | 568.0 | 75.8 | 15.3 | 165.0 | 171.0 | 55.0 | 5.0 | 1.607 ± 0.12 | 2.56 ± 0.338 |
SQ2 | Tabuk | 36.6 | 28.4 | 34.0 | DW | 600.0 | 7.3 | 725.0 | 464.0 | 54.0 | 25.0 | 120.0 | 135.0 | 55.0 | 4.0 | 1.93 ± 0.13 | 4.392 ± 0.372 |
SQ3 | Tabuk | 36.6 | 28.4 | 31.4 | DW | 604.0 | 6.4 | 1100.0 | 660.0 | 82.0 | 23.4 | 180.0 | 163.0 | 97.0 | 10.0 | 1.521 ± 0.118 | 4.058 ± 0.364 |
SQ4 | Tabuk | 36.6 | 28.6 | 32.0 | DW | 600.0 | 7.4 | 764.0 | 489.0 | 56.7 | 17.9 | 125.0 | 142.0 | 60.0 | 5.0 | 1.091 ± 0.103 | 1.746 ± 0.324 |
SQ5 | Tabuk | 36.6 | 28.4 | 31.2 | DW | 605.0 | 7.4 | 746.0 | 489.0 | 56.7 | 22.4 | 125.0 | 142.0 | 60.0 | 5.0 | 2.454 ± 0.145 | 5 ± 0.382 |
SQ6 | Tabuk | 36.5 | 28.4 | 26.5 | DW | 607.0 | 7.3 | 833.0 | 533.0 | 69.0 | 13.0 | 125.0 | 149.0 | 70.0 | 4.0 | 2.066 ± 0.134 | 5.146 ± 0.385 |
SQ7 | Tabuk | 36.6 | 28.4 | 32.0 | DW | 603.0 | 7.0 | 730.0 | 467.2 | 56.7 | 17.9 | 120.0 | 138.0 | 58.0 | 6.5 | 2.001 ± 0.132 | 3.663 ± 0.358 |
SQ8 | Tabuk | 36.6 | 28.4 | 38.8 | DW | 606.0 | 6.8 | 839.0 | 537.0 | 69.9 | 18.1 | 160.0 | 142.0 | 82.0 | 7.0 | 1.298 ± 0.11 | 2.671 ± 0.34 |
SQ9 | Tabuk | 36.5 | 28.4 | 27.2 | DW | 605.0 | 6.6 | 861.0 | 551.0 | 63.8 | 20.6 | 135.0 | 162.0 | 60.0 | 6.0 | 1.435 ± 0.116 | 3.741 ± 0.359 |
SQ10 | Tabuk_Tymaa | 39.3 | 28.0 | 27.6 | Irrigation | 600.0 | 7.8 | 487.0 | 267.9 | 72.0 | 13.4 | 54.0 | 196.0 | 46.0 | 7.1 | 0.278 ± 0.068 | 0.915 ± 0.312 |
AS11 | Tabuk_wajh | 36.7 | 29.0 | 27.7 | DW | 144.0 | 7.8 | 8500.0 | 4675.0 | 1200.0 | 144.0 | 120.8 | 4520.0 | 490.0 | 36.5 | 0.394 ± 0.075 | 0.565 ± 0.307 |
SQ12 | Tabuk_Tymaa | 38.1 | 27.4 | 27.9 | Irrigation | 300.0 | 7.7 | 460.0 | 253.0 | 51.2 | 8.6 | 70.0 | 64.0 | 43.0 | 2.2 | 1.557 ± 0.12 | 2.92 ± 0.329 |
AS13 | Tabuk_wajh | 36.7 | 26.8 | 26.1 | DW | 45.0 | 7.6 | 2760.0 | 1518.0 | 240.0 | 57.6 | 166.0 | 540.0 | 100.0 | 20.3 | 0.415 ± 0.075 | 0.59 ± 0.307 |
AS14 | Tabuk_wajh | 36.7 | 26.8 | 28.6 | DW | 50.0 | 7.8 | 3160.0 | 1738.0 | 302.4 | 37.4 | 136.0 | 720.0 | 290.0 | 16.0 | 0.617 ± 0.084 | 0.829 ± 0.31 |
AS15 | Tabuk_Duba | 35.3 | 28.0 | 26.4 | DW | 49.0 | 7.6 | 7650.0 | 4208.0 | 704.0 | 86.4 | 152.0 | 2200.0 | 372.0 | 12.3 | 0.581 ± 0.082 | 0.907 ± 0.312 |
AS16 | Tabuk_Duba | 36.1 | 27.1 | 25.8 | DW | 0.0 | 7.9 | 5480.0 | 3014.0 | 403.2 | 103.7 | 88.0 | 1928.0 | 560.0 | 18.6 | 0.158 ± 0.061 | 0.54 ± 0.307 |
AS17 | Tabuk_Bad | 34.7 | 28.4 | 28.6 | DW | 12.0 | 8.0 | 3540.0 | 1947.0 | 320.0 | 170.9 | 84.0 | 744.0 | 378.0 | 12.8 | 1.27 ± 0.131 | 0.178 ± 0.331 |
AS18 | Tabuk_Umluj | 37.6 | 25.1 | 29.1 | DW | 50.0 | 7.6 | 3790.0 | 2085.0 | 110.4 | 112.3 | 930.0 | 672.0 | 550.0 | 10.6 | 0.472 ± 0.075 | 0.025 ± 0.298 |
AS19 | Tabuk_Duba | 36.3 | 27.4 | 27.9 | DW | 42.0 | 7.7 | 5040.0 | 2772.0 | 592.0 | 43.2 | 780.0 | 1320.0 | 570.0 | 33.2 | 0.179 ± 0.063 | 1.198 ± 0.316 |
AS20 | Tabuk_Duba | 36.3 | 27.1 | 26.6 | DW | 0.0 | 7.8 | 3400.0 | 1870.0 | 272.0 | 32.6 | 388.0 | 816.0 | 335.0 | 19.5 | 0.221 ± 0.066 | 0.668 ± 0.308 |
AS21 | Tabuk_wajh | 37.3 | 26.3 | 38.6 | DW | 23.0 | 7.4 | 5110.0 | 2810.5 | 384.0 | 34.6 | 1344.0 | 1248.0 | 450.0 | 31.2 | 0.257 ± 0.068 | 0.992 ± 0.312 |
AS22 | Tabuk_wajh | 37.2 | 26.0 | 30.0 | DW | 30.0 | 7.1 | 3870.0 | 2128.5 | 220.8 | 57.6 | 132.0 | 360.0 | 430.0 | 44.6 | 0.265 ± 0.068 | 0.206 ± 0.301 |
AS23 | Tabuk | 36.1 | 27.4 | 31.0 | DW | 34.0 | 8.0 | 1714.0 | 942.7 | 214.4 | 16.3 | 138.0 | 524.0 | 110.0 | 19.3 | 0.215 ± 0.075 | 0.563 ± 0.338 |
AS24 | Tabuk_wajh | 36.9 | 26.6 | 31.2 | DW | 150.0 | 7.7 | 9850.0 | 5417.5 | 1008.0 | 38.4 | 960.0 | 3200.0 | 320.0 | 20.5 | 0.257 ± 0.068 | 0.445 ± 0.305 |
Min | 12.0 | 6.4 | 460.0 | 253.0 | 51.2 | 8.6 | 54.0 | 64.0 | 43.0 | 2.2 | 0.158 ± 0.061 | 0.025 ± 0.298 | |||||
Max | 607.0 | 8.0 | 9850.0 | 5417.5 | 1200.0 | 170.9 | 1344.0 | 4520.0 | 570.0 | 44.6 | 2.454 ± 0.145 | 5.146 ± 0.385 | |||||
Average | 316.6 | 7.4 | 3012.4 | 1683.6 | 278.3 | 47.1 | 283.2 | 849.8 | 235.0 | 14.9 | 0.939 ± 0.095 | 1.855 ± 0.330 | |||||
std | 274.8 | 0.4 | 2737.1 | 1483.5 | 311.5 | 44.3 | 345.7 | 1109.7 | 196.7 | 11.6 | 0.735 ± 0.028 | 1.670 ± 0.027 | |||||
SASO | 1400.0 | 1000.0 | 200.0 | 150.0 | 200.0 | 250.0 | 250.0 | 50.0 | – | – | |||||||
WHO | 6.5–8.5 | 1600.0 | 1200.0 | 200.0 | 150.0 | 200.0 | 250.0 | 250.0 | 45.0 | 0.1 | 1.0 |
4.3 Hydrochemical Classification
4.4 Radioactivity Analytical Results
- Granite basement exhibits an average content of 3 mg/kg of uranium: 1–190 Bq/kg of radium (226Ra).
- Sandstone is not known for its high radionuclide concentration; it shows about 1 mg/kg of uranium and activity of less than 60 Bq/kg of 226Ra.
- Shale with an average content of 3.7 mg/kg of uranium has 10–2300 Bq/kg of 226Ra. Therefore, the origin of radioactivity in the Saq aquifer water seems more likely related to leakage of radioactive materials from adjacent layers into the Saq, rather than being intrinsic to Saq waters.