A number of land and water use activities that take place in the upper Olifants River system are of strategic importance to South Africa (for example, mining, agriculture, industry and power generation) (Basson 2010). These activities rely heavily on a variety of goods and services that they derive from the aquatic ecosystems in the area to sustain their processes. Unfortunately, there have been consequences, and the Olifants River has been described as one of the most polluted rivers in southern Africa due to the number of human-induced stressors that are present in the catchment.
Although the upper Olifants River is affected by many variables, such a system is usually driven by a few key controlling variables (for example, heavy metals from acid mine drainage and high total phosphate concentrations from inflows of untreated or partially treated sewage). Associated with these key variables are threshold concentrations that contribute to the resilience of the system and hence its ability to withstand and recover from various stressors (Basson 2010).
TRIBUTARY OF THE UPPER OLIFANTS CATCHMENT - HEAVILY IMPACTED BY INDUSTRIAL EFFLUENT. SOURCE: CSIR 2010
CSIR Risk Assessment of Pollution in Surface Waters of the Upper Olifants River System: Implications for Aquatic Ecosystem Health and the Health of Human Users of Water
The purpose of the CSIR study is to identify the critical variables in the upper Olifants River and its tributaries, and to determine their thresholds by making use of a novel set of ecological indicators at different trophic levels (the position that an organism occupies in a food chain), as well as a comprehensive set of molecular techniques that provide accurate estimates of the ecosystem health in the study area. These data will be used to clearly identify the sources of different stressors and will be particularly useful to develop and refine appropriate water quality management responses, decision making processes, or remediation measures for the rivers in the upper Olifants River catchment (Basson 2010).
The study is undertaken by an experienced group of scientists representing several scientific disciplines. This is a highly complex catchment and aquatic ecosystem, with many factors involved in creating the current situation. Rigorous research is needed to understand the drivers of change and the multiple ecological processes and responses arising from the change (Basson 2010).
The CSIR is also conducting a study in the Waterberg area to determine the ecological status of the rivers.
