Grabouw - High levels of pollution, including E. coli, have been found in the water in Grabouw in the Western Cape, a water management organisation said on Friday.
"This poses a serious threat to the fruit industry in the region, one of the pillars of the Western Cape economy," said Fabion Smith, an official from the Breede Gouritz Catchment Management Agency (BG-CMA).
The agency released a report detailing the findings of tests conducted on four key water sources in the area, including tributaries to the Palmiet River - a main water source for the fruit industry.
The report found "extremely high levels of E coli", which could be attributed to an overflow of sewage.
E coli is a type of bacteria that once ingested can cause certain, usually gastrointestinal, illnesses.
It is often used as a indicator of water safety.
BG-CMA began its investigations following complaints of a stench in the Swannies River and Klipdrift River as well as photographs taken of what appeared to be contaminated foam.
Smith said it was clear that there was insufficient treatment of industrial water in Grabouw, resulting in a high level of contaminants and a damaging decline in water quality."
"We have already identified two industrial plants as possible sources of the pollution. Fortunately, we have been alerted in time to take precautionary measures and prevent damage to vital exports," he said.
Smith said the plants had subsequently been inspected.
"[We] have been assured by the management and owners of their full co-operation to prevent any further contamination," said Smith.
Inspections of all other industrial plants in the area would follow.
Superintendent of water use at the Theewaterskloof Municipality (TWK), Rose Myburgh, said it was not clear what all the sources of the pollution were.
"At this stage no one specific source of the E coli pollution for example can be pinpointed," said Myburgh.
BG-CMA - an agency established according to the terms of water management legislation - was now planning to institute a permanent water monitoring programme in Grabouw.