False Bay fish, snoek and hottentot, are full of contaminants - UWC study
A study conducted by the UWC chemistry department has shown that fish caught by small-scale commercial fishers in Kalk Bay are also contaminated by pesticides, herbicides and industrial chemicals, among others. In their peer-reviewed paper, senior Professor Leslie Petrik at the UWC’s chemistry department and Cecilia Y Ojemaye tested for 15 different chemical compounds in the fish fillets, gills, livers and intestines.
“We did this because we found all of these chemical compounds in the sewage effluents from various wastewater treatment plants in Cape Town.
These effluents are being released into local rivers and estuaries, as well as into the surf zone in False Bay,” Petrik said. She said the chemicals were found in the effluents because people in the city bought and used products containing them.
“We take medicines and use chemicals in our households. Hospitals, industry and businesses are also using these chemicals and not treating their contaminated effluents. The chemical compounds don’t get broken down by the sewage treatment process as the sewage treatment process is mainly aimed at removing the solids using microbes, flocculation and settling,” Petrik said.
The report stated that in fish such as snoek and hottentot, the anti- inflammatory drug diclofenac and antibiotics were found in all the fish parts, with the fillet having the highest concentration, while anti-epileptic medication was also found in all parts but with the liver having the highest concentration. Petrik said big pharmaceutical companies were to blame for this, as they made and sold drugs that didn’t break down.
“We reported mainly on the pharmaceuticals in the article we published. These were not the only compounds we found in the fish. We also found pesticides, herbicides, industrial chemicals, etc in the same fish. These chemicals were also found in the city sewage effluents, highlighting the need for more effective sewage treatment.
“This is not due to dumping - it is due to our love affair with chemicals.
“But big pharmaceuticals and the industrial producers of these chemicals are also at fault, as they should not be designing or selling compounds that persist into the environment,” she said.
Petrik added that the City could not afford to do proper tests on the seawater, but that chronic and acute risk quotient values were very high and could not be ignored by consumers.
“The City does not have the capability for testing for these chemical compounds. They have to send samples overseas for the analyses and this is very expensive so is not done routinely. The City tests according to the national guidelines, which also don’t mandate testing for these compounds, so we have a huge legislative gap which needs urgent attention,” she said.
Pavitray Pillay, manager of the WWF-Sassi programme, said: “The information in relation to pollutants detected in local seafood is of concern and underscores our view at WWF that we should be paying far more attention to the waste we are putting into natural systems - from plastics to E-coli, to pharmaceuticals. WWF-Sassi urges consumers to eat off our ‘green’ list based on sustainability criteria, but this does not encompass health guidelines. This is something that local health authorities should look into. WWF-Sassi will also contact the University of the Western Cape to fully understand the results and implications of this research.”
Mayco member for water and waste services Xanthea Limberg said: “Chemicals of emerging concern are accumulating in the environment all over the world, even in places far from human settlement. The fact that these are detectable in Cape Town is not unusual. This is due to the pervasiveness of these chemicals in modern society, rather than sub-standard wastewater management.”
Limberg said the World Health Organisation also states that although chemicals being discharged in wastewater was an area where further research was needed, concentrations of possibly hazardous chemicals typically detected in wastewater were well below those that would represent a risk to public health.
“Current media coverage of the issue we believe is seriously exaggerating the concentrations detected in the environment, and scientific findings thus far have not pointed to risks to public health or that of marine life.
“Municipal wastewater treatment, even in the most highly developed countries in the world, is not yet advanced enough to effectively remove chemicals,” Limberg said. Petrik said she did not agree with the City’s view.@MarvinCharles17