AN ANALYSIS OF THE GROUNDWATER CHEMISTRY OF THERMAL SPRINGS IN THE SOUTPANSBERG BASIN IN SOUTH AFRICA: RECENT DATA

摘要

Investigations were carried out in order to assess the groundwater chemistry of aquifers in the Soutpansberg Basin. Water samples were collected from Sago le, Tshipise, Mphephu, Dopeni and Siloam thermal springs during the winter and summer seasons of May 2013 and October 2013, respectively. Water temperature, pH, electrical conductivity, dissolved oxygen and total dissolved solids were determined on-site, using a multiparameter meter. The concentrations of major anions (Cl-, NO3-, SO42- and PO4-3,) were determined using ion chromatography. Cations (Na+, Ca2+, Mg2+, K+ and Fe2+) were analysed using optical emission spectrometry. The highest water temperatures during both the summer and winter seasons were recorded at Siloam (59.4 degrees C and 59.0 degrees C), Tshipise (51.2 degrees C and 51.2 degrees C) and Dopeni (46.0 degrees C and 46.5 degrees C), respectively. The thermal spring water samples were found to be rich in sodium, bicarbonate and chlorine with very low concentrations of other element species. The chemical composition of Sago le and Siloam thermal springs indicates the same origin of Na-Cl-HCO3 waters, typical of deep circulating groundwater. None of the thermal springs exhibited any evidence of groundwater pollution. The seasonal variations in the chemical composition of winter and summer samples were found to be negligible and consequently show that the source of the hot water was deep and therefore not affected by seasonal rainfall recharge.