Marine life chemical threat

Scientific evidence shows that pharmaceutical chemicals, by-products of prescription drugs used for everything from depression to diabetes, are among a chemical cocktail being flushed into oceans through sewage spills, and are causing damage to marine life.

The scientific paper says these chemical compounds could cause far more harm than the sewage itself, such as feminisation or sterility of fish populations, cancer, growth deformities, foetal abnormalities and hormonal disturbances.

“These compounds may bioaccumulate in marine organisms, and move up the food chain to humans who eat seafood, ultimately causing the same effects,” said authors of the scientific paper, “Desalination and Seawater Quality at Green Point, Cape Town: A study on the effects of marine sewage outfalls”, published by Leslie Petrik, Lesley Green, Adeola P Abegunde, Melissa Zackon, Cecilia Y Sanusi and Jo Barnes.

And your daily cup of coffee is part of the problem, says Professor Petrik, from the department of chemistry in the faculty of natural science at the University of the Western Cape.

Professor Petrik was awarded the National Science and Technology Forum Water Research Commission Award last year for her work towards achieving sustainable water management, knowledge generation and solutions – the award is termed a “Science Oscar”.

“If coffee gives some people the jitters imagine what it does to a crab?” she pointed out. “We don’t know, yet we carry on regardless. We should be applying the precautionary principle,” she said.

She said we are large creatures, whereas most marine organisms are much smaller, and their complexity and response to these chemicals is hardly understood yet.

“If we break the food chain by wiping out smaller organisms, we are in serious trouble. A recent report said we are exterminating insects at about 2.5% a year. If that is happening on land, it is happening in the ocean,” she said.

The seawater study found that once these compounds are in the environment it is very hard to destroy them, and natural degradation processes take weeks or many months, if ever.

“Many megalitres of chemically contaminated sewage and sewage effluents are released from our cities and towns on a daily basis all over the country, without proper treatment,” Professor Petrik said.

Compounds such as antibiotics, analgesics, blood lipid regulators, natural and synthetic hormones, beta-blockers, anti-diabetic and blood pressure drugs, as well as chemicals from toiletries, disinfectants and perfumes are washed out with the effluent into the coastal waters.

Professor Petrik says numerous persistent organic chemicals have been identified by the World Health Organisation (WHO) as being recalcitrant to biodegradation and persist in the environment.

“Our legislation is very out of date and almost none of these chemicals are being banned from products and usage by our Department of Environmental Affairs (DEA) and governmental regulations. South Africa is a signatory to the international conventions, and the DEA and Department of Water and Sanitation (DWA) have started banning a few compounds, but they do it one by one, and there are many thousands of chemical compounds out there that should not be used in our country,” she said.

She said there needs to be much more regulatory oversight and rapid action.

“Our water quality guidelines are very outdated as well and do not stipulate limits of discharge for these compounds; hence the water providers, such as the City, can say without blinking an eye that they comply with the legislation as Xanthea Limberg (mayoral committee member for water and waste services) persists in doing. Yet that hides a huge public health hazard as most municipalities are not checking for levels of these compounds in drinking water supplies,” she said.

Professor Petrik says the City’s wastewater treatment plants need to be overhauled if there’s any hope of removing the chemicals from our water.

“We would need to ensure that all our wastewater treatment plants had advanced oxidation systems such as UV, ozone, peroxide, combined with cavitation, etc, installed. These advanced oxidation systems work rapidly by generating free radicals that rip the compounds apart, but they need to be operated correctly and monitored for efficiency properly,” she said.

Professor Petrik said a lot of research had been done on different advanced oxidation treatment systems and what was needed is a combination of oxidation systems to eradicate these compounds from effluents or drinking water.

“These systems would be considerably cheaper than the very expensive membrane systems being sold to municipalities, and do not require expensive maintenance, high pressures nor disposal of toxic sludges,” she said.

She urged consumers to use biodegradable products as far as is possible.

“We each can make a huge difference by our daily choices and avoid being part of the problem,” she said.

Professor Petrik said suppliers should also be pressurised into finding safe, alternative compounds which do biodegrade and said any substitute should be exhaustively tested for impacts before it is sold to consumers.

“The producers should be subject to class-action as is being done in America, for example, for perfluorooctanesulfonic acid (PFOS) as these companies produce and sell such compounds knowing full well that these will persist and contaminate the environment.”

Ms Limberg said data on specific bodies of water was available to the public on request.

She said while the WHO had acknowledged in 2017 that the list of chemical hazards in wastewater could be broad, it said studies had shown that concentrations typically detected were well below those that would represent a risk to public (human) health.

Ms Limberg said the City was mandated to treat wastewater to the standards issued by the relevant national department, and the removal of what are known as chemicals of emerging concern (CECs) is not addressed.

“The City must stress, however, that the only way to stop these compounds from entering our environment would be for us as a society to stop using them. There is currently no technology which can remove all these emerging contaminants from wastewater,” she said.

She said no country in the world currently had discharge standards for CECs, although America and the European Union were busy promulgating legislation for a limited number of them.

“However, neither processes have been completed to date. Research into effective full scale treatment processes for the removal of CECs is still under way, and consensus regarding the most effective treatment for all 120 known CECs has not yet been reached. In short, this is a global problem and by no means unique to Cape Town or even South Africa,” she said.

Ms Limberg said that endocrine disruptors were found in hundreds of common plastic, household cleaning, pharmaceutical and cosmetic items, and entered the sewerage system through our homes.

She said research by the WHO in the last 10 years showed endocrine disruption to be far more extensive and complicated than realised a decade ago, but clarity was still needed on which chemicals were problematic and what level of exposure would constitute an unacceptable risk.

“At this stage the effects of long-term, low-level exposure to endocrine disruptors are not fully understood,” she said.

Ms Limberg said the City continually investigated and assessed new technologies with a view to improving wastewater treatment processes and was following developments in research around contaminants of emerging concern.