An environmental risk assessment of the Klip river using water quality indices

The Klip River wetland is one of the most economically important ecological river system in South Africa as it plays two roles: water purification in the Vaal River system and is also a source of water. However, several studies have demonstrated that the wetland is extremely degraded and has lost capability to perform the two functions. The main objective of this study was to evaluate the Klip River water quality compliance with guidelines for its designated uses i.e. domestic, aquatic and agricultural uses. Furthermore, risks associated with these uses were established. Water samples were collected at 12 points along the Klip River, monthly from February 2016 to January 2017 and analysed for heavy metal pollution using Inductively Coupled Plasma Mass Spectrometry (ICPMS). The environmental risk assessment was done using the Heavy Metal Pollution Index (HPI), Potential Ecological Risk Index (PERI) and the Comprehensive Risk Index. Findings revealed that the HPI for aquatic, domestic and agricultural uses were far above the critical index rendering the Klip River unfit for domestic and agricultural uses; and sustaining aquatic life. Furthermore, at a majority of the sampling sites along the profile of the Klip River, the PERI was very high suggesting that there is a serious threat to ecological communities. It can be concluded that there is a significant threat to ecological communities in the Klip River from heavy metal pollution. Therefore, it is recommended that programs to rehabilitate and restore the Klip River wetland should be developed.