Water quality of the Bloemspruit stream on the outskirts of Bloemfontein, Free State, South Africa.

Abstract

Introduction: The streams in the Free State play a crucial role in providing water for agricultural, industrial and recreational activities as well as in domestic households for sanitation purposes. These streams also provide a healthy home for numerous aquatic animals and plants. However, in recent years, there has been an upsurge in stream water pollution by anthropogenic activities. These include domestic, agricultural and industrial activities, such as waste water treatment plant (WWTP) that dispose of effluent containing high concentrations of emerging contaminants into the streams. The polluted water may cause illness in and deaths of humans and animals as well as kill less tolerant aquatic organisms resulting in a declined biological diversity of the stream. Therefore, water quality of the Bloemspruit and its tributaries, the Fonteinspruit and the Renosterspruit was assessed to determine the health and deterioration of the stream. Methodology: For water quality assessment, water samples were collected from 11 sampling sites in Bloemspruit stream and its tributaries during four sampling rounds. These water samples were assessed for four physical, seven chemical and two microbiological properties as well as eight emerging contaminants. The impact of pollution on the macroinvertebrate population and the macroinvertebrate habitat was conducted. The calculations of the Water Quality Index (WQI), the South African Scoring System score (SASS), the Average Score per Taxon (ASPT) and the Index of Habitat Integrity (IHI) score were used to determine the health of the Bloemspruit and its tributaries. Results and discussion: The results revealed that of the twenty-one properties of water measured, only five properties, i.e. temperature, pH, sulphate, total hardness and estradiol, were compliant in all the sampling rounds. The measurements of dissolved oxygen were relatively low. However, turbidity, nitrates, phosphates, E. coli, total coliforms, atrazine, metolachlor, terbuthylazine, carbamazepine, estrone, 17a-ethinylestradiol and bisphenol A all demonstrated relatively high measurements when compared with the proposed water quality limits for the protection of aquatic ecosystems. The WQI revealed that none of the sampling sites were of good quality. However, 45% demonstrated a fair condition, 45% were marginal and 10% poor. The SASS and ASPT scores revealed that 44% of the sampling sites were severely impaired with only a few tolerant macroinvertebrate taxa present, while the remaining 56% of the sampling sites were critically impaired. The IHI score demonstrated that 89% of the macroinvertebrates sampling sites had a moderately modified habitat, however, the remaining sampling site, S9, revealed a largely modified macroinvertebrate habitat. Conclusion: This study revealed that the water quality of the Bloemspruit and its tributaries is poor. Several anthropogenic activities along the stream may have attributed to the poor status of the Bloemspruit water quality. These include the waste water treatment plant (WWTP), agricultural farming of animals and pastures as well as formal and informal settlements. Therefore, humans that use the water are at risk of being exposed to water-borne pathogens caused by high levels of E. coli and coliforms in the water. These pathogens can cause gastrointestinal diseases, such as diarrhoea, typhoid fever, cholera and other conditions including ear and eye infections. Additionally, the animals are also in danger of contracting diseases transmitted by this polluted water.