A new study that tracked the increase of marine pollution along the Cape Peninsula coastline found that medicines consumed by humans ended up contaminating marine life and cycled back through the food they consumed.
The project's findings, SanOcean, come as some organisations have appealed against the decision by the Department of Forestry, Fisheries and the Environment (DFFE) to approve the City's application for a permit to continue pumping raw sewage into the ocean for another five years.
Epidemiologist Professor Jo Barnes said the study, conducted over four years, would form part of studies in other parts of the world so that scientists can get an accurate picture of the possible damage that land-based pollution poses.
Environmental nano-chemist at UWC, Professor Leslie Petrik, 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.”
The study focused on chemical compounds found in muscle relaxants, antispasmodics, antibiotics, painkillers, pesticides and toxic industrial chemicals such as perfluorinated compounds, now being banned in the US.
According to the scientists, these were also found in the Cape’s marine environment due to the wastewater treatment plants not having the capacity to degrade such compounds found in sewage and remove them.
“We tracked and found not only those chemicals but many others in marine species such as mussels, limpets, sea urchins, starfish, seaweeds and fish, and most recently in penguins, all around our Peninsula, showing the extent of the sewage pollution.
“These sea creatures are thus in contact with a sewage-related chemical soup all the time in the sea around our Peninsula as shown by our studies,” said Petrik.
Although the concentration of each chemical in the seawater was “relatively low”, the concentration in the flesh of the fish and other marine biota was concentrated up to a thousand times higher than the seawater concentration, and many of these chemicals are present at the same time in the same seafood or fish, added Petrik.
Petrik called on the government to hold municipal wastewater treatment managers to account who do not meet discharge specifications.
“Authorities need to promulgate and enforce much more stringent regulations about effluent water quality and make it mandatory for all treatment plants to comply with much higher standards,” Petrik added.
She also said that the country’s water quality guidelines were “very lax” and there were few consequences if the quality guidelines were exceeded.
“Our wastewater treatment plants all over the country need to be upgraded and operated to specification.”
Petrik said the public also had to play a role and only use necessary medications and minimise usage of household or industrial chemicals and pesticides.
“We should not ever flush medications down the toilet. The toilet or drains should not be treated like a dustbin, because those discarded pharmaceuticals and other chemicals ultimately end up in the sea.”
As part of the study, a graduate from Environmental Humanities at UCT, Amy Beukes, sampled mussels more than a kilometre from the outfall discharge point in Hout Bay and found high levels of diverse pharmaceuticals in the mussels.
Some of the chemical compounds also impacted sexual development and fertility, the scientists warned.
“The studies on the effects of sperm included a number of species including oysters, fish and even humans. Fertility seems to be affected over time and there is also some indication that feminisation occurs in some of the sub-studies.
“While extinction will not happen over the short term, this is another indication that all the chemicals and disease-causing organisms that we release into the environment by disposing of sewage into the sea are having some unexpected harmful effects,” said Barnes.
Environmental researcher at UCT, Dr Neil Overy, also explained that despite protests, the City renewed its discharge licences to continue with “the outdated practice” at three sites, Green Point, Camps Bay and Hout Bay.
“The outfall pipe has resulted in significant faecal pollution of the Green Point coastline being reported for more than 100 years despite the engineers’ assurances that it would be the best solution. Nowadays, this cannot be so,” he added.
The City claimed that the report's findings were consistent with similar reports from worldwide showing that human pollution was evident “where you look for it”.
“Modern humans are massive consumers of resources, and as a result, we produce huge volumes of waste. None of this waste, especially chemicals, disappears. The findings in Cape Town are no different from anywhere else in the world,” said the City.
A scientist from the University of California, Professor Daniel Schlenk, warned that the use of excessive chlorine for disinfection could lead to highly toxic compounds formed during sewage treatment or desalination.
He said the toxic compounds were implicated in marine species dying out along the California coastline.
And in Norway, a sewage plant that served several towns treated all the sewage to secondary and tertiary levels before the effluent was discharged into the ocean via an outfall pipe, according to Professor Daniela Pampanin from the Norway’s University of Stavanger.