A study of the sea water quality in Cape Town, spanning a period of two years, has concluded that the City’s sea marine outfalls poses no significant risk to human health and do not measurably affect inshore water quality or the wider environment. And the better news is that bacteria from the outfalls is not reaching bathing areas so swimmers have nothing to worry about.
Over the years pictures have surfaced pointing out how sewage is negligently dumped into the ocean, close to some of the busiest swimming beaches. Angry Capetonians questioned how marine life and the quality of water was affected by the outfalls.
Commissioned by the City of Cape Town, the Council for Scientific and Industrial Research (CSIR) were appointed to undertake a detailed assessment. The study started in late 2015 and was concluded in mid-2017.
The findings confirmed the metro’s position that the outfalls are not outstripping the assimilative capacity of the ocean. It also found that there are no measurable risks to human health posed by the outfalls through either swimming at the beach or consumption of fish caught off our coastlines. In addition, near-shore pollution (when it occurs) is as a result of urban run-off. This is typical of all urban environments.
To ensure a comprehensive assessment the study was designed to assess and measure:
the quality of the sea water near the outfalls
the possible accumulation of substances in ocean floor sediment
the possible accumulation of synthetic chemicals in animal tissue
the characteristics and toxicity of the effluent
Councilor Xanthea Limberg, City’s Mayoral Committee Member for Informal Settlements, Water and Waste Services; and Energy said, “Our society produces a lot of waste and it is unavoidable that this waste eventually finds its way back to the environment in one form or another. There are over 84 000 synthetic chemicals that have been made by humans and no wastewater treatment plant is able to remove all of these components from effluent. This study confirms, however, that at current levels this waste can be safely assimilated by the ocean.”
The study also looked at whether bacteria from the outfalls was reaching the bathing areas, finding that this was nothing for bathers to worry about. Bacteria dissipated within 300 metres of the diffusers (the outfalls are 1,7km off-shore), which is echoed by the results of our coastal waters monitoring programme, and the continued status of Camps Bay and Clifton as Blue Flag beaches.
“Given the often negative and sensationalist coverage around these outfalls we are happy to have conclusive proof that disposing of waste in this way is not posing significant risks to bathers or the marine environment,” said Councillor Limberg.
Photography: Jean Tresfon and Pixabay