Political interference? Denial? Researchers vs city over extent of water contamination in Cape Town

A clash is brewing between independent researchers and city managers over claims of “political interference and denial” about long-standing water pollution posing public health risks in Cape Town's rivers, wetlands and coastal waters.

Cape Town has denied claims that it misrepresented scientific evidence about long-standing water pollution. 

This follows a peer-reviewed study led by University of Cape Town (UCT) researchers that accused the city of ignoring, or undermining, evidence of serious contamination in rivers, wetlands and coastal waters.

Lead author Prof Lesley Green said the study, conducted by local and international researchers, found “evidence of repeated denial, interference and misrepresentation of science by the city.

“Based on more than a decade of multidisciplinary work, the research highlights how [City of Cape Town] officials have ignored or undermined independent scientific findings about serious public health risks, despite extensive evidence of raw and poorly treated sewage entering urban water bodies and coastal zones,” said Green, who is director of Environmental Humanities South at UCT. 

But the city told TimesLIVE Premium on Wednesday that it was widely regarded as a leading city for transparency on coastal water quality and would respond formally through academic channels.

Green said the city discharged more than 40 megalitres of raw sewage into the Atlantic Ocean daily. Runoff from informal settlements and failing wastewater plants also polluted the Indian Ocean and inland waters. 

“This contamination carries significant risks for human health, ecosystems and the economy,” she said. 

Green said that despite efforts to share research findings with the public and the city through various platforms, including a dedicated website and documentary, researchers were met with resistance, online abuse and public denouncements.

The team tracked 11 years of city reports, political statements and media commentary, identifying 18 forms of what they called “science miscommunication” — including withholding test results, misinterpreting findings and using commissioned science to drive political narratives. 

“Instead of engaging with evidence, city officials have appropriated the authority of science for brand and political reputation management. Science is only authoritative to the extent that it is open to counter-evidence,” said Green.

The researchers called for structural reforms, including ending conflicts of interest where the same departments oversaw environmental quality and funded research, releasing real-time pollution data, improving data quality and protecting the independence of scientists. 

Both the volume of waste from a large city, and new chemical compounds that do not break down in the open environment, makes that approach unworkable.

—  Prof Lesley Green, lead author 

Green also criticised the city’s wastewater management model, describing it as outdated and incapable of handling the volumes of a modern city. 

“Both the volume of waste from a large city, and new chemical compounds that do not break down in the open environment, makes that approach unworkable,” she said. 

The team worked with communities to build what Green called “an evidence-based record of contamination and its social and ecological effects”, despite “denial and resistance”. 

“We acknowledge some recent steps by the mayoral office, including reversing the 2021 bylaw that prohibited independent water testing and releasing summer beach water quality data. This is a start, but much more needs to be done to restore public trust in science and secure clean, safe water for all Cape Town residents,” she said. 

Responding on Wednesday, the city said it would review the study, then respond via academic channels. 

“In general, Cape Town is widely recognised as South Africa’s leading city for transparency on coastal water quality data,” said a spokesperson.  

The city operated the country’s most comprehensive coastal water quality monitoring programme, sampling more than 100 locations, including weekly testing at 45 sites and daily testing at high-use beaches such as Camps Bay and Strand. 

“All data is published online for the public and academics to study and draw their own conclusions. The data is produced by independent experts and laboratories and is not open to manipulation by the city.” 

It added the public could check updated water quality data on the city website, and that wastewater treatment upgrades were being heavily invested in. 

“It’s unfortunate that the study seemed to not recognise Cape Town’s standout transparency efforts,” the city said.

“The city was not contacted for input prior to publication, which could have helped the study present a more balanced picture.” 

The city said it had made 10 years of independent monitoring and analysis on marine outfalls publicly available, including water sampling data from 18 stations. The work was done by external marine science experts and presented quarterly at the city’s permit advisory forum, open to the public.