Aspects of the water quality, macro-invertebrate communities and fish health of the Klipspruit River, South Africa

The Klipspruit is a highly impacted river situated near the city of Johannesburg in the Gauteng Province of South Africa. It flows through the Soweto Township, a developing urban area with large informal settlements which... [ view full abstract ]

The Klipspruit is a highly impacted river situated near the city of Johannesburg in the Gauteng Province of South Africa. It flows through the Soweto Township, a developing urban area with large informal settlements which contribute greatly to the contamination of this freshwater ecosystem. The aim of this study was to assess the water quality, the macro-invertebrate community assemblages as well as fish health-related aspects of the Klipspruit. Sampling was done in 2013 and 2015. The water quality assessment included the analyses of selected physico-chemical parameters as well as organic and inorganic water quality components. The macro-invertebrate assessment was done using the South African Scoring System Version 5 (SASS5) and the fish health assessment included a standard necropsy and a histopathological assessment of the hepatic and gonadal tissues of the Sharptooth catfish Clarias gariepinus. The water quality results showed high levels of faecal coliform bacteria, especially during the 2015 survey, raising concerns regarding possible human health effects following exposure to the contaminated water. The inorganic chemical analyses of the water samples showed high levels of Aluminum, above the specified target water quality range for aquatic ecosystems. The macro-invertebrate assessment also indicated poor water quality as a low diversity of only pollution-tolerant taxa was identified. The fish health assessment showed macroscopic abnormalities of the urogenital papillae and the gonads of the sampled fish and the microscopic assessment confirmed intersex in 30% of male fish collected during the 2015 survey. The histopathological findings suggest that the pollutants contaminating the river may include endocrine disrupting chemicals. No macroscopic or microscopic abnormalities were identified in the livers of the sampled fish. Similar results were obtained for the 2013 and the 2015 surveys, indicating no improvement in the water quality, macro-invertebrate assemblages or fish health throughout the study period.