Water quality impacts on instream biota of the Shingwedzi River, South Africa

Abstract

Water quality, macroinvertebrate diversity (using SASS5) and fish diversity (using the fish response assessment index) of the Shingwedzi River system were monitored in 2007/2008 to determine the present status of the system. Possible water pollution sources were identified by aerial survey. Water quality parameters frequently exceeded the threshold of potential concern values set by SANParks. SASS scores were generally low, due mainly to organic pollution as a result of the lack of infrastructure in the catchment. Fish responses indicated a general ecological decline to a 'category C' river: moderately modified. Of concern was the absence of some fish species that historically occurred in this system. Sources of pollution such as acid mine drainage from abandoned mines, inadequate sewerage infrastructure and habitat destruction due to siltation and sand mining are discussed.

African Journal of Aquatic Science 2010, 35(1): 1–11