Cape Town's Sewage Issue: Science vs Politics

Urban water bodies – rivers, lakes and oceans – are in trouble globally. Large sewage volumes damage the open environment, and new chemicals and pharmaceutical compounds don’t break down on their own. When they are released into the open environment, they build up in living tissues all along the food chain, bringing with them multiple health risks.

The city of Cape Town, South Africa, is no exception. It has 300km of coastline along two bays and a peninsula, as well as multiple rivers and wetlands. The city discharges more than 40 megalitres of raw sewage directly into the Atlantic Ocean every day. In addition, large volumes of poorly treated sewage and runoff from shack settlements enter rivers and from there into both the Atlantic and the Indian Oceans.

Over almost a decade, our multi-disciplinary team, and others, have studied contamination risks in Cape Town’s oceans, rivers, aquifers and lakes. Our goal has been to bring evidence of contaminants to the attention of officials responsible for a clean environment.

Monitoring sewage levels in the city’s water bodies is essential because of the health risks posed by contaminated water to all citizens – farmers, surfers, and everybody eating fish and vegetables. Monitoring needs to be done scientifically and in a way that produces data that is trustworthy and not driven by vested interests. This is a challenge in cities where scientific findings are expected to support marketing of tourism or excellence of the political administration.

Our research findings have been published in multiple peer-reviewed journals. We have also communicated with the public through articles in the media, a website and a documentary.

Cape Town’s official municipal responses to independent studies and reports, however, have been hostile. Our work has been unjustifiably denounced by top city officials and politicians. We have been subject to attacks by fake social media avatars. Laboratory studies have even received a demand for an apology from the political party in charge of the city.

These extraordinary responses – and many others – reflect the extent to which independent scientific inquiry has been under attack.

We set about tracking the different kinds of denial and attacks on independent contaminant science in Cape Town over 11 years. Our recently published study describes 18 different types of science communication that have minimised or denied the problem of contamination. It builds on similar studies elsewhere.

Our findings show the extent to which contaminant science in Cape Town is at risk of producing not public knowledge but public ignorance, reflecting similar patterns internationally where science communication sometimes obfuscates more than it informs. To address this risk, we argue that institutionalised conflicts of interest should be removed. There should also be changes to how city-funded testing is done and when data is released to citizens. After all, it is citizens’ rates and taxes that have paid for that testing, and the South African constitution guarantees the right to information.

We also propose that the city’s political leaders take the courageous step of accepting that the current water treatment infrastructure is unworkable for a city of over 5 million people. Accepting this would open the door to an overhaul of the city’s approach to wastewater treatment.

The way forward

We divided our study of contaminant communication events into four sub-categories:

• non-disclosure of data
• misinformation that gives a partial or misleading account of a scientific finding
• using city-funded science to bolster political authority
• relying on point data collected fortnightly to prove “the truth” of bodies of water as if it never moves or changes, when in reality, water bodies move every second of every day.

We found evidence of multiple instances of miscommunication. On the basis of these, we make specific recommendations.

First: municipalities should address conflicts of interest that are built into their organisational structure. These arise when the people responsible for ensuring that water bodies are healthy are simultaneously contracting consultants to conduct research on water contaminants. This is particularly important because over the last two decades large consultancies have established themselves as providers of scientific certification. But they are profit-making ventures, which calls into question the independence of their findings.

Second: the issue of data release needs to be addressed. Two particular problems stand out:

• Real-time information. Water quality results for beaches are usually released a week or more after samples have been taken. But because water moves all the time every day, people living in the city need real-time information. Best-practice water contamination measures use water current models to predict where contaminated water will be, given each day’s different winds and temperatures.
• Poor and incomplete data. When ocean contaminant data is released as a 12-month rolling average, all the very high values are smoothed out. The end result is a figure that does not communicate the reality of risks under different conditions.

Third: Politicians should be accountable for their public statements on science. Independent and authoritative scientific bodies, such as the Academy of Science of South Africa, should be empowered to audit municipal science communications.

Fourth: Reputational harm to the science community must stop. Government officials claiming that they alone know a scientific truth and denouncing independent scientists with other data closes down the culture of scientific inquiry. And it silences others.

Fifth: The integrity of scientific findings needs to be protected. Many cities, including Cape Town, rely on corporate brand management and political reputation management. Nevertheless, cities, by their very nature, have to deal with sewage, wastes and runoff. Public science communication that is based on marketing strategies prioritises advancing a brand (whether of a political party or a tourist destination). The risk is that city-funded science is turned into advertising and is presented as unquestionable.

Finally, Cape Town needs political leaders who are courageous enough to confront two evident realities. Current science communications in the city are not serving the public well, and wastewater treatment systems that use rivers and oceans as open sewers are a solution designed a century ago. Both urgently need to be reconfigured.

Next steps

As a team of independent contaminant researchers we have worked alongside communities where health, ecology, livestock and recreation have been profoundly harmed by ongoing contamination. We have documented these effects, only to hear the evidence denied by officials.

We recognise and value the beginnings of some new steps to data transparency in Cape Town’s mayoral office, like rescinding the 2021 by-law that banned independent scientific testing of open water bodies, almost all of which are classified as nature reserves.

We would welcome a dialogue on building strong and credible public science communications.

This study is dedicated to the memory of Mpharu Hloyi, head of Scientific Services in the City of Cape Town, in acknowledgement of her dedication to the health of urban bodies of water. Her untimely passing was a loss for all.

This article also drew on Masters theses written by Melissa Zackon and Amy Beukes.