Cape Town - Exposure to toxic chemical compounds found in polluted seawater have the potential to cause the sperm of both humans and sea creatures to become incapable of fertilising an egg, say academics in a University of Western Cape (UWC) comparative spermatology group.
Local and international scientists met in Durbanville last Friday where they presented their studies on health conditions of the marine environment in Cape Town as part of the SANOcean project.
The release of sewage into a marine protected area has been a subject of controversy for years, with experts and activists slamming the Department of Forestry, Fisheries and the Environment’s decision to grant the City a 5-year permit to pump sewage into the ocean via marine outflows at Green Point, Camps Bay and Hout Bay.
According to the academics, gross chemical contamination from poorly treated sewage was evident, and even reached Robben Island.
Studies showed that Atrazine, a banned pesticide, was detected in most of the samples analysed at all sampling points around the Cape Peninsula.
Norway’s professor Magne Sydnes from the University of Stavanger said antibiotics, perfluorinated compounds used in fire extinguisher foams or as waterproofing and in non-stick coatings as well as in paints, were also seen as compounds that were severely polluting the marine environment.
Professor Liana Maree, Dr Shannen Keyser and Dr Monique Bennet from the comparative spermatology group said: “Sperm from both humans and sea creatures such as oysters, which broadcast their sperm, as well as penguin sperm, could be affected by the presence of these toxic chemical compounds even at very low levels of exposure, making the sperm swim more slowly and become incapable of fertilising an egg.
This would impact on the survival of these species, and even human sperm was found to be highly susceptible to being incapacitated by exposure to these chemicals.”
PHD candidate Stephanie Dreyer also revealed in her results that not only does the chemical mixture from the faeces reach Robben Island but was also found in fish bought from Kalk Bay Harbour, penguin carcasses, eggs sampled from Boulders Beach and Robben Island colonies.
UWC chemistry professor Leslie Petrik said the coastline from Green Point all the way around the Peninsula, including False Bay from Miller’s Point to Rooi Els, was contaminated by chemicals from inadequately treated sewage.
“The practice of discharging untreated sewage through the three marine outfalls has added to the extensive chemical pollution of seawater, sediments and marine biota,” she said.
Petrik said the rapid growth in the city’s population was not matched by adequate sanitation service provision over the last two decades, resulting in numerous sewage spills and contamination.
UCT’s Dr Neil Overy of Environmental Humanities South said the city still argued that proper treatment was too costly.
“The outfall pipe has resulted in significant faecal pollution of the Green Point coastline being reported for more than 100 years despite the engineers’ assurances that it would be the best solution. It may have been possible to argue in bygone days that this practice was not harmful, despite plentiful evidence to the contrary, but nowadays this cannot be so, given the plethora of modern chemicals we all use for various purposes such as to address illnesses, fight infections, soothe pain, chase away insects, kill weeds, dye our hair, wash our clothes and dishes, to name a few,” said Overy.
The City said its three marine outfalls had preliminary treatment in the form of screenings removal.
“The preliminary treatment includes the removal of wastewater constituents such as rags, sticks, floatables, grit and grease that may cause maintenance or operational problems with the treatment operations, processes and ancillary systems. The current operation at the outfalls also includes two stages of screening, namely coarse and fine screens, as part of the preliminary treatment of the raw wastewater.”
It said a study was commissioned that would determine the feasibility of various higher level pre-treatment interventions and the report on this would be complete by June 2023.
According to the City, seven specialist marine science studies were conducted over the last six years.
“The pollution is concentrated in the allowable mixing zone located close to the diffuser, and does not yet show evidence of significant or deleterious environmental impacts.
Their overall key conclusion is that the marine outfalls are meeting their design objectives in reducing potential deleterious ecological and/or human health effects.”
Cape Times