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City disputes experts claims over chemicals in ocean

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The City of Cape Town and scientists at the University of the Western Cape (UWC) are at loggerheads over whether the chemicals detected in ocean water along the Cape Coast are a risk to the health of human and marine life. The findings of a recent study conducted by UWC’s chemistry department has grabbed the attention of the public, after it found that pharmaceutical and industrial chemical compounds are accumulating in the flesh of fish caught by small scale commercial fishers.

Initially, the study was conducted on mussels, but the tests were upped to accommodate the top of the marine food chain. The study used a sample set of randomly selected fish from Kalk Bay which showed contamination of antibiotics, pain killers, antiretrovirals, disinfectants, and industrial chemicals.

The University’s Chemistry Departments senior professor Leslie Petrick and Cecilia Y. Ojemaye tested for 15 different chemical compounds in the fish fillets, gills, liver, and intestines. Species tested include Snoek, Bonita, Hottentot (Cape bream) and Panga.

Chemicals and compounds uncovered include the analgesic/anti-inflammatories Diclofenac and Acetaminophen, the antiepileptic drug Carbamazepine, the antibiotic Sulfamethoxazole, the disinfectant Triclosan, as well as various industrial chemicals found in pesticides, flame retardants, and personal care products.

“We’ve been studying marine organisms for a while, to understand the impact of sewerage on our coastline. As you know we’ve got several marine outfalls, the pipes going into the sea from the pump stations, in Green Point, Camps Bay and Kalk Bay. Then there are several partial streams that are entering False Bay from the big wastewater treatment plants,” said Petrick.

The professor explained that the chemical compound does not completely metabolise in the body, as is evident through the presence in our excrement.

She explained that they wanted to determine its impact on the marine environment. Although the contamination levels found were fairly low, it does not mean that it was not a problem.

“There were some that were concerning, such as that which was considerably higher in snoek. Calculations indicated that there was an acute risk with eating a lot of (that) fish. If you eat one or two pieces nothing will happen to you but if you eat it regularly it may start affecting you.”

The study also threw the spotlight onto sewage infrastructure.

“We know that a lot of sewage infrastructure is aging and falling apart because we’re finding sewage in our storm water drains as well. That means that the City is not maintaining the infrastructure,” said Petrick.

The professor also pointed to desalination plants treating water for human consumption.

“I’ve spoken to the City about this and I’ve provided solutions in terms of the way they should treat the water if they want to reuse it. Also, from the desalination plants, we have to make sure that the sea water that’s being taken in is actually safe for consumption.”

Petrick said that the City denies that there are any concerns.

“The City keeps on saying it doesn’t discharge untreated or partially treated effluent into the ocean and there’s a big move afoot to reuse our sewage as drinking water. And if this is happening to the fish- where effluence is being diluted a thousand times – it shows that it is extremely important- that if you’re going to use sewage that you do an extremely good job of cleaning it up.”

The City’s Councillor for Water and Waste Services Xanthea Limberg said there is no risk to public health.

“The World Health Organisation states that, while further research is needed, concentration of chemicals typically detected in wastewater are well below levels that will represent a risk to public health,” said Limberg.

Limberg accused the media of making a mountain out of a molehill.

“Current media coverage is seriously exaggerating the concentrations detected in the environment, and scientific findings this far have not pointed to risk to public health or marine health.”

Petrick, however, accused the City of not providing access to its own tests.

“They (City) keeps on saying that I’m exaggerating that the findings are false. They keep completely quiet about their results and they won’t release the results to any of the rates-payers’ associations,” he added.

The professor questioned whether the City will wait until it’s too late.

“This study (shows) the warning signs. The City keeps saying there’s no acute problem but if there is an acute problem it means that 50% of the fish population will die. Is the City going to wait until (then) before they will act?”

Concerns have also been raised about the commercial fishing industry.

“As it is, our fish stock has collapsed tremendously over the past few years. Everyone says it’s because of over-fishing but a lot of these drugs cause feminization. In other words, they turn fish into (female) and if that happens you lose your fish stock.”

Petrick urged commercial fishermen to head the warning, or face losing their livelihoods.

“I hope (small-scale fishermen) are taking notice and that they start putting pressure on the city to start treating the effluence properly, or else we’re going to lose our fish stock.”

VOC


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