Coastline contaminated by chemicals from inadequately treated sewage, researchers say

An apparently pristine picture as viewed from Chapman's Peak, Hout Bay, Cape Town. Picture supplied

An apparently pristine picture as viewed from Chapman's Peak, Hout Bay, Cape Town. Picture supplied

Published Mar 28, 2023

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Cape Town - Experts and environmental activists waging war against ocean sewage pollution from the City of Cape Town’s marine outfalls are finding international support for their cause.

Their fight was reinforced by fresh support from Norwegian and other international academics at a stakeholder engagement last week on the impact of outfalls on Cape Town’s marine environment.

Numerous groups have challenged the Department of Forestry, Fisheries and the Environment’s decision to grant the City a five-year permit to pump sewage into the ocean via marine outflows at Green Point, Camps Bay and Hout Bay.

Local and international academics gave alarming input relating to the effects of this discharge into the ocean at a stakeholder engagement meeting in Durbanville at the weekend as part of a project funded by Sanocean, a bilateral research co-operation programme between the Research Council of Norway and South Africa’s National Research Foundation.

Chemistry professor Leslie Petrik from UWC said: “Our coastline, from Green Point all the way around the Peninsula and including False Bay from Miller’s Point to Rooi Els, is contaminated by chemicals from inadequately treated sewage.”

Petrik said the rapid growth in the city’s population was not matched by adequate sanitation service provision over the past two decades, resulting in numerous sewage spills and sewage-related contamination of rivers and the coastline with bacteria and toxic chemicals.

Amy Beukes, a graduate in environmental humanities at UCT, also described her study in Hout Bay, where sanitation problems were experienced due to inadequate service provision, and where there has been a history of community protests against the installation of the marine outfall.

A paper by UWC chemistry researcher Cecilia Ojemaye and others, titled The burden of emerging contaminants upon an Atlantic Ocean marine protected reserve adjacent to Camps Bay, Cape Town, South Africa, was published in December last year.

It found gross chemical contamination from inadequately treated sewage.

The researchers said: “Data revealed that this Atlantic Ocean marine protected environment is affected by the presence of numerous and diverse emerging contaminants that could only have originated from sewage discharges. The complex mixture of persistent chemicals found in marine organisms could bode ill for the propagation and survival of marine protected species, since many of these compounds are known toxicants.”

Alex Lansdowne, chairperson of the mayoral advisory committee on water quality in wetlands and waterways, said the City fully supported data transparency and appreciated the work of the various scientists advocating for cleaner ocean and river water quality in Cape Town.

However, Lansdowne said the biggest source of these pollutants was Cape Town’s ageing wastewater treatment plant infrastructure, like Potsdam, which will soon be receiving a R5 billion upgrade, and not the marine outfalls.

“I do not dispute any of their data and value the growing body of data being built around water quality that will in time help the City better manage water quality together with residents and academia,” Lansdowne said..

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