Has monitoring failed the Olifants River, Mpumalanga?

Abstract

Water quality monitoring in the Olifants River catchment, Mpumalanga, is evaluated using river water dissolved sulphate levels, one of the best indicators of pollution related to acid mine drainage. Assessment of long-term water quality records shows that monitoring has not been carried out systematically. In that it fails one of the most fundamental criteria of good environmental monitoring practices. At some monitoring stations sampling frequency has been scaled down from approximately weekly to monthly intervals over time, despite evidence for increasing and problematic levels of pollution. At the Loskop Dam dissolved sulphate levels have increased more than 7-fold since the 1970s evidently due to increasing levels of pollution within the Little Olifants River catchment. At 4 of the 7 long-term monitoring stations river water sulphate levels exceed the 100 mg/ℓ threshold value for aquatic ecosystem health most of the time for the duration of the record, and all of the time since about 2001.

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