Recent research by Cape Town scientists Dr Joe Burns and Professor Leslie Petrick has sparked a dispute with the City of Cape Town over the quality of the city's coastal waters.
The debate revolves around the results of Project Blue, a citizen-led pilot study conducted in November and December 2024. The study suggests there is potential for sewage contamination on several beaches, including Camps Bay, Clifton and the Strand.
Project Blue reported the presence of E. coli and enterococci in water samples, raising concerns about public health risks for beachgoers.
The researchers claimed that their method complies with international scientific standards, including sterile sample collection, temperature-controlled transportation, and rapid laboratory analysis within four hours. They were intended to provide a snapshot of water safety to inform swimmers.
Dr Burns and Professor Petrick emphasized that their study was not intended to be a comprehensive study, but rather a pilot project to identify potential risks. However, their findings quickly faced pushback from the City of Cape Town.
Eddie Andrews, the city's deputy mayor and member of the Mayor's Committee for Spatial Planning and Environment, questioned the reliability of Project Blue's findings.
Mr Andrews said the city's analysis carried out by a laboratory accredited by the South African National Accreditation System showed consistently high water quality across 30 coastal recreation nodes during the holiday season.
Of the approximately 300 samples taken, 100% met the recreational use threshold based on enterococcus levels, a globally recognized standard for assessing sewage contamination in seawater.
Mr Andrews criticized Project Blue's inclusion of E. coli as a countermeasure, citing international guidelines that say it is unsuitable for marine environments.
The city also challenged the accreditation of the laboratory used by Project Blue, claiming it was not accredited to analyze enterococci and E. coli in seawater.
Mr Andrews said the report was “limited and misleading”, cited no solid scientific references and focused disproportionately on known pollution hotspots such as Milnerton Lagoon Beach. He suggested that he was guessing.
Dr Burns and Professor Petrick defended the findings, calling the city's response “pretty hysterical” and accusing authorities of diverting attention from the underlying problem. They point to systemic challenges such as malfunctioning sewage systems and ocean drainage, which they believe are contributing to the ongoing pollution.
“This was a citizen science effort aimed at supporting public health,” Petrick said. “Instead of engaging constructively, the city is trying to silence scientists.”
The researchers acknowledged that the scope of their study was limited, but argued that it highlights important issues that require further investigation.
The city has launched a summer dashboard that provides weekly updates on enterococcus levels at 30 popular beaches, with the aim of reassuring the public and encouraging informed decision-making.
Mr Andrews stressed that Cape Town's extensive sampling operation ensured a safe and enjoyable experience for beachgoers, while any pollution incidents were quickly addressed.
