Petrik’s study, conducted with colleagues from the University of Cape Town and Stellenbosch University, said city council tender documents for desalination plants “make the assumption that the tens of millions of litres a day of untreated effluent discharged into the ocean . are dispersed out to sea and that in-take sea water to the desalination plants will contain only inorganic salts, and not organic chemical pollutants or microorganisms”.
Sea water samples collected at 22 points near Granger Bay in June, July and August proved this assumption untrue, they said.
“The results are consistent with kayakers’ claims that on occasion the water is a health risk,” he said.
Petrik’s team also analysed limpets, mussels, sea urchins, starfish, sea snails and seaweed for evidence of pollutants, and said they found high levels of chemical compounds that provided evidence of long-term exposure.