Groundwater chemistry: a case study of the Mesta River Basin

Article in Press
Pages: 
pp. 35-46
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
Laboratory of Telematics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 8, 1113 Sofia, Bulgaria
Abstract: 

The present study describes the hydrochemistry of ground waters found in the Mesta River Basin, located in the south-western part of Bulgaria. The groundwater’s composition can be expressed as follows: Ca2+ > Na+ > Mg2+ > K+; Ca2+ > Mg2+ > Na+ > K+ in equivalent units for the cations, and HCO3 > SO42– > Cl in equivalent units for the anions. The chemical composition of the studied groundwater can be described as calcium-bicarbonate. The calcium ions make up from 17.90% to 38.62% (30.18% on average), and the bicarbonate ions make up from 35.30% to 48.98% (43.70% on average) of all ions. Taken together, the calcium and bicarbonate ions make up from 61.44% to 87.60% (73.88% on average) of all ions. The groundwater itself is of slightly alkaline nature, having pH of 7.3 to 8.6, and TDS of 67 mg/l to 611 mg/l. One groundwater sample from the Mesta River catchment area was found to be of the low-mineralized type (TDS = 193 mg/l) alkaline water (pH = 9.8) in the Mesta Lowlands – the Banichan groundwater mineral source. The water can be described as sodium-bicarbonate, with sodium ions making up to 93.5% of the cations, and bicarbonate ions – 69.6% of the anions. Out of all ions, the sodium ions were found to be 48%, and the bicarbonate ions – 33.86%. The sequence of ions is in the following order: Na+ > Ca2+ > Mg2+ > K+, and HCO3 > Cl > SO42– > CO32–.

Keywords: 

groundwater, hydrogeochemistry, major ions, Mesta River Basin, south-western Bulgaria

DOI: 
https://doi.org/10.52321/GeolBalc.50.2.35

VOLUME 50 (2)/August 2021

Department of Geology, Palaeontology and Fossil Fuels, Faculty of Geology and Geography, Sofia University “St Kliment Ohridski”, 15 Tsar Osvoboditel Blvd, 1504 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Laboratory of Telematics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 8, 1113 Sofia, Bulgaria