Marine life overdosing on what is flushed out to sea
CAPETONIANS may revel in their city’s being Africa’s coffee capital, but their addiction to the rich brew is giving sea urchins and starfish a potentially dangerous buzz.
Researchers at the University of the Western Cape have also discovered that these marine creatures living 40m under the surface of Table Bay are unwittingly being given a perpetual boost from the energy drink Red Bull.
These are among the findings of research led by Professor Leslie Petrik to deter mine whether 12 known chemical compounds are present in the sea and the extent to which they are bioaccumulating in marine life.
The results signal a “public health crisis second to none”, warns Petrik: “Imagine taking a dose of painkiller, epilepsy medication, beta blockers, diuretics and thyroid treatments and some caffeine all at once, every day, in every glass of water you drink.
“That is what we’re subjecting these organisms to, because our sewage systems are just not designed to remove the many chemicals we use or consume.
“In many of our coastal cities, the sewerage effluent is directly released into the ocean, untreated.”
The partially metabolised compounds Petrik’s team found in marine filter feeders included acetaminophen, found in painkillers such as Panado and Tylenol, other phar maceuticals, caf feine from coffee, tea and Red Bull, Bisphenol A, found in plastic packaging, as well as several compounds used in non-stick coatings and textile waterproofing.
“We are continually releasing these compounds into the environment without understanding their full effects. When you try to break Bisphenol A down, for example, it becomes 15 other chemical compounds.”
Of the levels of caffeine detected in the marine animals, Petrik says: “Studies have been done on caffeine, comparing it to different drugs. Scientists gave spiders a range of psychedelic drugs as well as caffeine, and it was found caffeine disrupted their spinning abilities the most. We just don’t know the effect on marine life.”
Consider that there are more than 87 000 persistent organic pollutants, or compounds that don’t break down in the environment. Chemicals found in shampoo, toothpaste, washing powder and flea powder, as well as medications and antiseptics, pass through water treatment systems and end up in rivers, dams – and the ocean.
The City of Cape Town has several marine outfalls that it says discharge wastewater “deep underwater, far into the sea where the effluent is safely dispersed”.
It adds: “While many people may feel uncomfortable about discharging largely untreated wastewater into the sea, it’s important to consider that marine outfalls are carefully designed to safely disperse wastewater deep underwater far from the shore.
“They are located in areas where ocean currents help to disperse and carry the effluent away from the coast. The enormous volume of the sea helps to dilute the waste to nearly undetectable concentrations, and bacteria and pathogens die off while mixing with the sea water.”
But Petrik is worried: “We want to expand our research to see what other parts of the coastline are being affected. There are 129 marine outfalls across South Africa, where many big cities on our coast are pumping sewage into the ocean and into marine reserves.
“Products that contain oestrogen, such as birth control pills, can stop the proper development of male fish in the embryonic stage, with the result that, with long-term exposure to high enough concentrations, an entire fish population can be wiped out within one generation.”
Not all of these chemical compounds end up in the sea.
“Instead they’re captured in the sludge from the sewage treatment plants that may be used as farm fertilisers, and it isn’t yet known whether these chemicals are making their way into our food.
“Antibiotic resistance is not just caused when you don’t complete a course of pills.
“The combination of antibiotics and antiseptics that end up in our water systems are knocking out the microbes that are susceptible to them, but are allowing other resistant microbes to proliferate.”
Inland, malfunctioning wastewater treatment works are also to blame.
Petrik’s unit is developing water treatment systems based on advanced oxidation, which generates free radicals that can break down hazardous molecules. “We can’t wait for the government to change the laws or councils to build better water treatment plants.”