Abstract:
In this study, three sampling sites (Tshipise thermal spring, Mphephu thermal spring
and Siloam borehole) in Limpopo Province South Africa were considered for an
investigation into the mineral composition of their water and soil samples. Tshipise
and Mphephu thermal springs are well developed and located within tourist resorts.
On the other hand, Siloam is a borehole on the grounds of a private household. The
water is used for various domestic purposes such as laundry, general cleaning of the
household and bathing. Water and soil samples from the three sites were collected
once per week every week in February 2018. The sampling bottles were spiked with
1M HNO3 before sampling to keep any metal ions present in the water samples in
solution. The soil and water samples were analysed for their chemical composition
using X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry
(ICP-MS) respectively. XRF analysis of the soil samples found many major oxides of
which SiO2 made up 63.67%, 85.37% and 46.28% by mass of Tshipise, Mphephu
and Siloam soil samples respectively. XRF analysis also showed the presence of
dangerous levels of heavy metals such as As, Tl, Pb and V. The analysis of the
water samples by ICP-MS found that Tshipise, Mphephu and Siloam mineral water
were soft, soft-moderately hard and soft-hard respectively with regards to the water
hardness scale according to the United States Geological Survey (USGS) and the
Water Quality Association (WQA). Analysis of water samples also found the
presence of As, Cd, Cr and V. Arsenic was found to occur at concentrations above
the Maximum Allowable Concentration (MAC) set by the World Health Organisation
(WHO) (10 μg L-1) for Tshipise, Mphephu and Siloam mineral water (13.63 μg L-1,
15.83 μg L-1 and 20.97 μg L-1 respectively). Water temperatures for the three sites
ranged from 38°C (Siloam borehole) to 64°C (Tshipise thermal spring). The pH
values were 7.25 (Siloam borehole), 7.40 (Mphephu thermal spring) and 8.67
(Tshipise thermal spring). Due to the presence of As, Tl, Pb, V, Cd and Cr, the
mineral water from all three thermal springs is unsafe to consume as it would lead to
serious negative health effects some of which are outlined in this study.
