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Why are we still consuming drugs in our ‘clean’ tap water?

We’ve known for some time that our drinking water is seriously contaminated with an assortment of pharmaceuticals and chemicals.

Perhaps, as consumers, we have become inured to the fact that the national standard for drinking water (SANS 241: 2015) does not take into account the need to remove these contaminants and therefore we can do nothing about the problem.

Research dating back some years identified such pollutants in our tap water. The findings were reiterated in research published in 2017 (see Desalination and seawater quality at Green Point, Cape Town: A study on the effects of marine sewage outfalls), and more recently.

The report by the six researchers (Leslie Petrik, Lesley Green, Adeola P Abegunde, Melissa Zackon, Cecilia Y. Sanusi and Jo Barnes) states: “Pharmacological compounds, such as the analgesic and anti-inflammatory drugs acetaminophen (also known as paracetamol) and diclofenac, the anti-seizure medication phenytoin, the antibiotic sulfame thoxazole and the antiretroviral lamivudine are made to be stable and effective at low doses. They are polar, lipophilic, soluble and nonvolatile compounds.

“For these reasons, many pharmaceutical compounds or secondary metabolites do not decompose, but survive in the environment to become persistent organic pollutants.

“The full impact of constant, low-grade, chronic exposure to a plethora of pharmaceuticals, antibiotics and cleaning products on marine organisms, the marine food chain, and human health is not yet fully known, but their ubiquitous presence in trace levels in the desalination intake water poses a potential risk to human health. Although some pharmaceuticals are unlikely to constitute a risk to humans as they are found in low concentrations and have a low toxicity, such as iopromide, other pharmaceuticals such as natural and synthetic sex hormones pose considerable risks to the aquatic environment.”

Key conundrums posed by the researchersconundrum medical

“In terms of the ‘polluter pays principle’, the costs of the chemical and pharmaceutical compound clean-up ought to be borne by the companies producing the substances. Pharmaceutical and chemical companies are among the wealthiest multinational corporations globally. While air polluters are required to ensure emissions are cleaned from the commons that is the air breathed by all, pharmaceutical companies and the chemical industry have not been contributing to the clean-up of pollutants in water systems.”

The researchers go on to state that “retailers and consumers of pharmaceuticals and common household chemicals need to review their contribution to the growing pollution of ocean ecologies. Our individual decisions have a huge collective impact”.

Bringing it homezandvlei at sunrise

A few days ago, Prof Lesley Green, deputy director of Environmental Humanities South at the University of Cape Town, and four other local and international researchers, wrote in an opinion article published in Daily Maverick that residents of Cape Town’s Zandvlei community who live along the banks of the Kuils River and below the nearby sewage works discharge point “are suffering from an array of medical complaints so severe that they have resulted in surgical interventions”.

The City of Cape Town has stated in the past that the Zandvliet facility only discharges treated effluent, but researchers dispute the claim based on their on-site observations. The upgrade of the Zandvliet plant has been delayed as a result of  challenges with the tender.

Prof Leslie Petrik of the University of the Western Cape’s chemistry department says that most of Cape Town’s waste water treatment plants were designed 20 to 30 years ago incorporating treatment technology of that era.

“The Zandvliet plant was built before the introduction of many of the new drugs and chemicals which currently flood sewage systems. Because of this, it is incapable of adequately breaking them down so they wash out into the ocean and contaminate marine life too. Traces of pharmaceutical products, pesticides and coffee have been found in marine life.”

She says that treatment plants in Cape Town are in dire need of upgrading in order to deal properly with more modern types of effluent.

Petrik lays the blame for the current state of affairs on both the city and on consumers.  And, of course, pharmaceutical companies.

“We are all so in love with chemicals that we use far too much every day,” she says. “We also need to start asking pharmaceutical companies why they are manufacturing drugs which are so poorly metabolised. The way that we design drugs needs a lot of attention.”

The researchers state technology is available to solve the waste treatment problem. The introduction of advanced oxidation systems at the end of the treatment process in waste water treatment plants will result in the proper treatment of effluent. The technology is available locally and internationally, but to date only a limited number of cities and towns in South Africa have introduced the systems.

HomeTimes has canvassed the views of a number of suppliers of waste water treatment technologies. Their replies should be provided in due course.

Words: Blake Wilkins


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