Water is the great cleaner,
and the great solvent.

Without water, homes and bodies and factories and hospitals would be filthy. But what cleans water?

Cape rivers and wetlands are extraordinary cleaners. Palmiet, the river plant, filters water. Rocks bounce water around in a stream infusing it with life-giving air, which sustains fish and aquatic plants. Wetlands clean water in soils. Sand is a great filter. Some swimming pools and even sewage systems use plants, sand and gravels as natural cleaning systems.

Water is used to clean cities with little thought as to what will clean it in turn. When rivers flow fast, they look like the perfect removal agent to take away solid waste. The result: wherever there is water, there are pollutants. In streams, rivers, and vleis, plastics are visible; so is tin and glass. All of these end up in the sea — whether they are in Johannesburg or Cape Town, Kinshasa or Luanda. The result is chips packets and coke cans in even the deepest ocean trench. Wind, storms, and littering—especially of plastic waste—can also send debris into waterways; over time, these break down into micro-plastics that are even found in rainwater.

Without water, homes and bodies and factories and hospitals would be filthy. But what cleans water?

Cape rivers and wetlands are extraordinary cleaners. Palmiet, the river plant, filters water. Rocks bounce water around in a stream infusing it with life-giving air, which sustains fish and aquatic plants. Wetlands clean water in soils. Sand is a great filter. Some swimming pools and even sewage systems use plants, sand and gravels as natural cleaning systems.

Water is used to clean cities with little thought as to what will clean it in turn. When rivers flow fast, they look like the perfect removal agent to take away solid waste. The result: wherever there is water, there are pollutants. In streams, rivers, and vleis, plastics are visible; so is tin and glass. All of these end up in the sea — whether they are in Johannesburg or Cape Town, Kinshasa or Luanda. The result is chips packets and coke cans in even the deepest ocean trench. Wind, storms, and littering—especially of plastic waste—can also send debris into waterways; over time, these break down into micro-plastics that are even found in rainwater.

Cleaning Up

A worldwide movement is growing to reduce plastic pollution. Kenya has banned plastic bags, even as the oil industry that sells raw materials for plastics, has lied to the public about how recyclable plastics are. Like the tobacco industry lied about smoking causing cancer, the oil industry has put millions into persuading the public that plastic recycling is viable. Plastics are typically used for seconds or minutes, but will endure from a few months to 600 years. Studies are finding plastic is being incorporated into rock, like sandstone, which could potentially last for millennia. That’s quite something when you consider that the last of the Neanderthals, a species of human, died out about 35 000 years ago, or that field-based agriculture only began about 10 000 years ago. What you choose to use for a few seconds, can last for a geological era.

Cleaning up the invisible pollutants in water is as important. Bacteria and viruses that cause diseases can accumulate in water that is not flowing. Sewage is one of the main sources of water-borne diseases in cities. Body waste is processed by water treatment plants, chemical toilets, and compost (humanure) toilets, which have become increasingly common. Over two centuries, Cape Town’s engineers and municipal officials have built pipes that take sewage to the ocean, where the idea is that it will be diluted to safe levels. None of these processes, however, are able to remove all the newly invented chemicals that have become part of daily life in the last three to four decades, that are in sewage and household wastewater and stormwater, and ultimately everything ends up in the ocean.

A worldwide movement is growing to reduce plastic pollution. Kenya has banned plastic bags, even as the oil industry that sells raw materials for plastics, has lied to the public about how recyclable plastics are. Like the tobacco industry lied about smoking causing cancer, the oil industry has put millions into persuading the public that plastic recycling is viable. Plastics are typically used for seconds or minutes, but will endure from a few months to 600 years. Studies are finding plastic is being incorporated into rock, like sandstone, which could potentially last for millennia. That’s quite something when you consider that the last of the Neanderthals, a species of human, died out about 35 000 years ago, or that field-based agriculture only began about 10 000 years ago. What you choose to use for a few seconds, can last for a geological era.

Cleaning up the invisible pollutants in water is as important. Bacteria and viruses that cause diseases can accumulate in water that is not flowing. Sewage is one of the main sources of water-borne diseases in cities. Body waste is processed by water treatment plants, chemical toilets, and compost (humanure) toilets, which have become increasingly common. Over two centuries, Cape Town’s engineers and municipal officials have built pipes that take sewage to the ocean, where the idea is that it will be diluted to safe levels. None of these processes, however, are able to remove all the newly invented chemicals that have become part of daily life in the last three to four decades, that are in sewage and household wastewater and stormwater, and ultimately everything ends up in the ocean.

How well are we
cleaning the water?

Waste Water Treatment Plants were typically designed decades ago, to remove microbial pollution and basic chemicals. New chemicals designed in more recent decades are not well removed unless an advanced treatment process is included. This means that they are not routinely broken down but are often just transferred from the liquid to the solid phase. Some may be removed, but not all.

Persistent chemical pollutants can pass through conventional wastewater treatment systems without adequate removal, ending up in the receiving environment, where they bioaccumulate (concentrate up) in orders of magnitude up the food chain. Moreover, they can react with one another in ways that are unknown to science because no laboratory is ever likely to experiment with all the possible combinations of molecules that come into a typical urban waste-water treatment plant. They can evaporate with water, and travel vast distances, and fall again as rain. For this reason it is more and more important that city dwellers learn how to look after our most precious city asset: water.

The presence of persistent chemical pollutants in waste-water effluents, which are ultimately discharged into the ocean, is of critical concern because they have long-term health outcomes for all marine organisms and those who eat them, including fish, people, sharks, marine mammals, turtles — and even the chickens, where the poultry industry is heavily dependent on fish meal. Grey water and liquid sewage effluents should also not be used for irrigation because of the many different chemicals contained in them. Also, much of the solid waste from sewage plants is spread on agricultural lands despite being highly contaminated, and these compounds may then be taken up in crops or animal fodder growing on contaminated soil.

Pollution Hotspots Around Cape Town

A peninsula city on the corner of a continent, Cape Town has approximately 300 km of ocean coastline, touching two ocean currents: the Benguela in the Atlantic that flows towards the north, and the Mozambique current from the Indian Ocean, that flows toward the west and the south — in turn affecting a third ocean, the Southern Ocean. Yet Cape Town daily sends about ten Olympic-sized swimming pools of sewage to sea — sewage that has been macerated (broken up) but not treated.

Sewage plumes observed near Hout Bay. Image: Jean Tresfon

The history of one of the four Atlantic Ocean outfalls in Cape Town’s Table Bay and on the Atlantic Seaboard is published in a paper by Cape Town researcher Neil Overy, who is affiliated with Environmental Humanities South. He is one of many researchers and citizen activists who have been studying and documenting water contamination issues around Cape Town.

The struggles over the Camps Bay sewage outfall are the focus of a dissertation by Melissa Zackon. In addition to sewage from the marine outfall, the sea water quality at Hout Bay is also directly affected by the water quality of the Disa River, that is heavily polluted by surface runoff from the shack settlements with poor sanitation in Imizamo Yethu. Research on seawater quality is being undertaken by Amy Beukes, and on shack settlement sanitation by Faith Gara.

Zandvlei, which empties into False Bay at Muizenberg

Equally worrying is the overflow and sewage spills into rivers and vleis that reach False Bay, south of Cape Town, via the Kuils River, the Eerste River, the Diep River, the Keyser River, and the Lotus Rivers. The vleis at Marina da Gama (Zandvlei) and Zeekoevlei have been in the news many times for severe sewage spills.

A doctoral dissertation by Environmental Humanities graduate Nikiwe Solomon focuses on the communities living along the Kuils River, and the many struggles over the management of the Kuils River. And into Table Bay on the Milnerton side, a legal battle is brewing between residents and the City because the river flowing into the Milnerton Lagoon is so heavily polluted. Read more >

Dr Jack on the cover of Noseweek, June 2019.

The waters of Cape Town’s urban oceans are so polluted that desalination has been impossible, and during the 2017/18 water crisis, the City spent hundreds of millions of Rands to install three desalination plants for emergency water. However, the Waterfront desalination project is in a court battle to recover costs, after it found the water was up to 400% more polluted than the official city figures that were given with the desalination plant call for tenders in January 2018. Herman Smit, head of the desalination company QFS, declared that:

“If I had known how dirty the water was I would have installed a sewage plant, not a desalination plant.”  Read more >

The other two desalination plants, one at Monwabisi and the other at Strandfontein, could not operate for many months due to ocean algal blooms that clogged their operating systems (algal blooms are worsened when sewage and fertilisers run into the ocean, and when waters are warm, ie the summer months, during Cape Town’s dry season). Their contracts were terminated early.

“Water pollution—along with drought, inefficiency, and an exploding population—has contributed to a freshwater crisis, threatening the sources we rely on for drinking water and other critical needs.” Christina Nunez, National Geographic website

Chemical Pollution

Chemical companies have taught us that to be clean is to get rid of ‘germs’ — while introducing thousands of longer-lasting pollutants that don’t break down in the environment, and which are easily absorbed into our cells because they are so similar to chemicals that our bodies make. Their tiny differences, however, make them toxic: some cause cancers; some disrupt the body’s endocrine system; some cause genetic changes (that is, they have “epigenetic effects”); some have neurological effects.

Harmful substances used daily including pesticides, fertilisers, household detergents, industrial chemicals, pharmaceuticals in sewage are the main causes of chemical pollution. Collectively, these are called Chemicals of Emerging Concern — and they are of such concern that the same body responsible for global climate negotiations, the UN Environment Programme, drafted the Stockholm Convention to govern their use. One of the chemicals of concern is Teflon, manufactured by DuPont Chemicals, which is scheduled to be phased out of production by 2025 and was the focus of a reality-based film, Dark Waters.

Chemical pollution can come from a variety of sources. Pollution can enter water directly, from run off from chemical agriculture for example, or through both legal and illegal discharges from factories, or imperfect water treatment plants. Spills and leaks from oil pipelines or hydraulic fracking operations can degrade water supplies. Many of these compounds are not biodegradable and persist in the natural environment, where they are taken up by marine organisms and consequently, pose a risk to humans and the food chain as a whole.

Chemical companies have taught us that to be clean is to get rid of ‘germs’ — while introducing thousands of longer-lasting pollutants that don’t break down in the environment, and which are easily absorbed into our cells because they are so similar to chemicals that our bodies make. Their tiny differences, however, make them toxic: some cause cancers; some disrupt the body’s endocrine system; some cause genetic changes (that is, they have “epigenetic effects”); some have neurological effects.

Harmful substances used daily including pesticides, fertilisers, household detergents, industrial chemicals, pharmaceuticals in sewage are the main causes of chemical pollution. Collectively, these are called Chemicals of Emerging Concern — and they are of such concern that the same body responsible for global climate negotiations, the UN Environment Programme, drafted the Stockholm Convention to govern their use. One of the chemicals of concern is Teflon, manufactured by DuPont Chemicals, which is scheduled to be phased out of production by 2025 and was the focus of a reality-based film, Dark Waters.

Chemical pollution can come from a variety of sources. Pollution can enter water directly, from run off from chemical agriculture for example, or through both legal and illegal discharges from factories, or imperfect water treatment plants. Spills and leaks from oil pipelines or hydraulic fracking operations can degrade water supplies. Many of these compounds are not biodegradable and persist in the natural environment, where they are taken up by marine organisms and consequently, pose a risk to humans and the food chain as a whole.

What are CECs?

Many chemical compounds resist breaking down in the environment. These are called Contaminants of Emerging Concern (CECs), a group of which are the Persistent Organic Pollutants or POPs. These include some pharmaceutical and personal healthcare products such as over-the-counter and prescription drugs (antibiotics, analgesics, blood lipid regulators, natural and synthetic hormones, β‑blockers, antidiabetics, antihypertensives, etc.) and household products such as soaps, detergents, disinfectants, perfumes, dental care products, skin and hair products, and surfactants, as well as these compounds’ degradation products. There is growing evidence that certain emerging contaminants could affect human and environmental health.

In studies done in Cape Town on sewage and ocean water, a number of different chemical compounds were tested for, including:

  • Antibiotics and antiseptics: e.g. Sulphamethozasole, Triclosan
  • Industrial chemicals: e.g. Bisphenol A, 2‑nitrophenol
  • Perfluorinated chemicals: perfluorooctanoic acid (PFOA), perfluoroheptanoic acid (PFHpA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA)
  • Pesticides and herbicides: e.g. atrazine, alachlor, simazine, metolachlor and butachlor
  • Pharmaceuticals: acetaminophen (ACT), diclofenac(DCF), lamivudine (LA), phenytoin (PHE), carbamazepine (CAR),
  • Natural chemicals: e.g. caffeine

These chemicals are only indicative of a far larger problem entailing many thousands of different compounds. So if one finds some of them in the environment one can be sure there will be many more. A CSIR study done in 2017 tested for about 55 different compounds and found many of them in the sewage being discharged. In the studies done by the Environmental and Nano Sciences Group at the University of Western Cape on local Waste Water Treatment plants, tests for a larger range of compounds were done, and many of these compounds were found in the sewage effluent before and after treatment, so were not removed adequately. The above list of compounds were all also found in the environment.

Jo Barnes, a leading epidemiologist from the University of Stellenbosch, describes how chemicals are being discovered in water that previously had not been detected or are being detected at levels that may be significantly different than expected. These compounds have unknown effects on the marine environment, especially in ever increasing concentrations.

When these pollutants reach the oceans they contaminate or otherwise affect marine organisms. Excess nutrients from fertilizers and sewage trigger massive blooms of algae that rob the water of oxygen, leaving dead zones where few marine organisms can live.

Some chemical pollutants accumulate deep into food webs and affect several species across the food chain, bioaccumulating in apex species like sharks and humans. Pharmaceuticals that are not fully metabolized by human bodies may end up in marine organisms and circulate back to humans who eat marine products. They can also evaporate and be transported great distances — making management of POPs a global responsibility.

Chemical pollutants in water bodies are linked to modulating various endocrine system pathways in both invertebrates and vertebrates therefore causing a variety of health issues and altering ecosystems. Specific pollutants leach into the ocean from other materials and affect marine wildlife. Many different chemical compounds found in household products, medicines, personal care products, and herbicides, accumulate in human and marine mammal blood. Our environment is increasingly being polluted with a mixture of many toxic chemicals whose impact on biodiversity and human health is not yet known.

Bioaccumulation

Bioaccumulation is the slow gathering and retention of chemical substances or compounds such as pesticides or pharmaceuticals in an organism. It occurs when an organism absorbs foreign substances at a quicker rate than the rate at which they can be broken down and excreted. Even when the toxin is not present in large quantities in the environment, chances of chronic poisoning may be higher in an organism due to toxins accumulating in its tissues, and in that of the organisms it feeds on.

Contaminants which can accumulate may be natural substances such as zinc or manmade chemicals and metals. Bioaccumulation occurs in both marine and terrestrial ecosystems, however, it’s important to note that current global criteria on identifying bioaccumulative substances focuses on water-breathing organisms and therefore are inadequate for protecting air-breathing organisms such as humans, birds and mammals. In some species bioaccumulation may be a form of defence, used to deter predators and non-toxic compounds may also bioaccumulate to toxic levels. Learn more here and here.

Focus on PFAs

What makes PFAS dangerous?

PFAS, an abbreviation for Per- and Polyfluoroalkyl Substances, (also PFC’s) are typically used in the production of fire-retardant foams, household cleaning products (stain, oil and water-resistant chemical products), Teflon non-stick pans, cosmetics, adhesives, lubricant oil additives, insecticides, paints and ink as well as medical equipment. They are also used to protect fabrics and found in rainproof jackets due to their resistance to grease, dirt and flame.

PFAS are dangerous because they act as endocrine disruptors, which may disturb the natural hormone function of organisms. Unfortunately, their attractiveness in industrial and household uses is the reason why they remain persistent in the environment for long periods and accumulate in human tissue. These can cause a variety of health issues, with no known medical interventions to remove such toxins from human tissues. Read more >

These chemicals accumulate slowly in living organisms, disrupting essential functions gradually over time which makes them challenging to study due to the delayed effect. An example of the toxicity of PFAS is seen through a recent study done on women firefighters in San-Francisco conducted after the women raised concern over an increase in rates of breast cancer among the workforce. According to studies like this one, PFAS are detectable in both humans and animals and are linked to the following health complications: high cholesterol, thyroid disease, testicular cancer, kidney cancer, and pregnancy-induced hypertension.

Focus on Pharmaceuticals

Pharmaceuticals enter the environment in several ways, by incomplete metabolism of medicines in bodies which are excreted through human waste; leftover medication is thrown down toilets or sinks; hospital waste and sewage plants. In some areas where limited sanitation causes sewage leakages, pharmaceuticals may be in the streets and environment, contaminating soils and plants, then deposited in water bodies through rain runoffs. As they are designed to maintain their strength from the manufacturer to the user’s medicine cabinet, and sometimes in the human body, this stability may make them persistent in the environment.

The use of pharmaceuticals is expected to increase due to higher standards of living and higher life expectancy as people use more drugs with age. Diverse pharmaceuticals have been found in the environment, including antibiotics, antidepressants, antiretrovirals, contraceptives, sedatives, deworming drugs. Moreover, pharmaceuticals are found in the environment as complex mixtures, and several studies have revealed that they can be toxic to other organisms due to their combined synergistic effect. (Learn more here and here.)

Diagram showing the flow of Pharmaceuticals. Source — Al Granberg 

Studying Chemical Pollution Around Cape Town

Professor Leslie Petrik from the Environmental and Nano Sciences Group (ENS) at the University of the Western Cape, along with a number of students have been monitoring emerging contaminants (ECs) of concern at various locations along the Atlantic and False Bay coastlines, to ascertain the chemical pollution levels in marine ecosystems. These studies have been undertaken by the research group due to ever-increasing concerns over the toxicological effect of ECs on marine and human life.

These emerging contaminants are discarded into the sewage system and sewage effluents are discharged into the ocean (as treated or untreated effluent). Other sources of chemical marine pollutants include industrial wastewater effluents as well as aquacultural and horticultural effluents that are discharged into the ocean.

Along the Cape Peninsula coastline, the presence of emerging contaminants such as pharmaceutical and personal care products (PPCPs), endocrine disrupting compounds (EDCs) and perfluorinated compounds (PFCs) in ocean water samples and beach sediment samples has been reported at different sampling sites (Camps Bay, False Bay, Kalk Bay and Green Point).

Some of the pharmaceuticals found in marine water samples include chemical compounds such as antibiotics, anti-diabetics, anti-ulcer, anti-inflammatory, antihistamine, beta-blockers, lipid regulating drugs as well as stimulants, antipyretics, analgesics and pharmaceutically active compounds such as hormones. Some common EDCs include pesticides, plasticisers, fungicides, flame retardants, surfactants, contraceptive pills as well as other phenolic compounds.

POP Abbreviations

EDC
endocrine-
disrupting
compounds

PFC
perfluorinated
compounds

PPCP
pharmaceutical and personal care products

Study sites around the Cape Peninsula in Cape Town

Study Samples

Professor Leslie Petrik from the Environmental and Nano Sciences Group (ENS) at the University of the Western Cape, along with a number of students have been monitoring emerging contaminants (ECs) of concern at various locations along the Atlantic and False Bay coastlines, to ascertain the chemical pollution levels in marine ecosystems. These studies have been undertaken by the research group due to ever-increasing concerns over the toxicological effect of ECs on marine and human life.

These emerging contaminants are discarded into the sewage system and sewage effluents are discharged into the ocean (as treated or untreated effluent). Other sources of chemical marine pollutants include industrial wastewater effluents as well as aquacultural and horticultural effluents that are discharged into the ocean.

Along the Cape Peninsula coastline, the presence of emerging contaminants such as pharmaceutical and personal care products (PPCPs), endocrine disrupting compounds (EDCs) and perfluorinated compounds (PFCs) in ocean water samples and beach sediment samples has been reported at different sampling sites (Camps Bay, False Bay, Kalk Bay and Green Point).

Some of the pharmaceuticals found in marine water samples include chemical compounds such as antibiotics, anti-diabetics, anti-ulcer, anti-inflammatory, antihistamine, beta-blockers, lipid regulating drugs as well as stimulants, antipyretics, analgesics and pharmaceutically active compounds such as hormones. Some common EDCs include pesticides, plasticisers, fungicides, flame retardants, surfactants, contraceptive pills as well as other phenolic compounds.

POP Abbreviations

EDC
endocrine-disrupting compounds

PFC
perfluorinated compounds

PPCP
pharmaceutical and personal care products

Study sites around the Cape Peninsula in Cape Town

Study Samples

Kalk Bay

Kalk Bay harbour is one of the last operational fishing harbours along the Cape Peninsula situated about 30 km from central Cape Town. Kalk Bay is located between the ocean and the mountain that is mostly sandstone.

In 2018, a study found that fish caught by small scale commercial fishers in the regions of False Bay and sold at Kalk Bay harbour is contaminated by antibiotics, pain killers, antiretrovirals, disinfectants, and industrial chemicals. In their peer-reviewed paper, Senior Professor Leslie Petrik 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, obtained from random daily commercial catches sold at Kalk Bay harbour in late 2017.

Results showed 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 were all present in various parts of the fish tested. Read more here.

Below are the study results of persistent organic pollutants (POPs) found in fish caught off Kalk Bay:

Kalk Bay harbour is one of the last operational fishing harbours along the Cape Peninsula situated about 30 km from central Cape Town. Kalk Bay is located between the ocean and the mountain that is mostly sandstone.

In 2018, a study found that fish caught by small scale commercial fishers in the regions of False Bay and sold at Kalk Bay harbour is contaminated by antibiotics, pain killers, antiretrovirals, disinfectants, and industrial chemicals. In their peer-reviewed paper, Senior Professor Leslie Petrik 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, obtained from random daily commercial catches sold at Kalk Bay harbour in late 2017.

Results showed 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 were all present in various parts of the fish tested. Read more here.

Below are the study results of persistent organic pollutants (POPs) found in fish caught off Kalk Bay:

False Bay

False Bay is a body of water defined by Cape Point (in the west) and Cape Hangklip (in the east). False Bay is ~30 km wide (at its widest section). The western and eastern shores of False Bay are characterised by mountainous terrain and rocky cliffs, while the northern shores are known for long and winding, sandy beaches. The low-lying, Cape Flats are located beyond the northern shores of False Bay. These northern shores are also home to the four wastewater treatment facilities located along False Bay (Cape Flats, Mitchell’s Plain, Zandvliet and Macassar wastewater treatment plants).

While there are no marine outfalls in False Bay, both the Strandfontein and Zandvliet Waste Water treatment works discharge poorly treated sewage effluents into the bay. Sewage undergoes primary and secondary treatment to remove nutrients and bacterial contamination and the treated water is supposed to meet minimum standards for the presence of microbial bacteria such as E.coli and Enterococcus, which are indicator organisms for the presence of other microbes. All these waste water treatment plants do not have tertiary treatment adequate to degrade or remove persistent organic pollutants and therefore discharge chemically laden effluents into the ocean. Water channelled from roads and gutters into stormwater drains, which then flow either directly to the sea, or into streams and rivers which discharge to the ocean, are also heavily polluted.

Current research by Cecilia Y. Ojemaye from Environmental and Nano Sciences Group (ENS) at the University of Western Cape, on the water quality in False Bay, reveals the impact of the chemical load being discharged together with sewage, upon the local marine environment. The study confirms that selected pollutants are bioaccumulating in organisms that are fixed in one place (such as limpets, mussels) and that the alleged high dilution of pollution by discharge of sewage into the oceanic environment is not operating effectively and poses high acute and chronic risk concerns.

The City of Cape Town has said that no testing or treatment for chemical compounds is undertaken when sampling treated waste water, such as those indicated in Ojemaye and Petrik’s study. They question that levels found in fish are harmful to humans. Read more here.

See the graphs alongside which indicate the chemical compounds found in seawater and marine sediments in False Bay.

Camps Bay

Camps Bay is an enclosed, shallow bay in Cape Town that is only 850 m wide. Camps Bay is a geographically isolated suburban area found between Table Mountain and the Atlantic Seaboard. Camps Bay beach runs along Camps Bay Drive, coming to an end at Maidens Cove and the seabed is composed of sand and exposed bedrock. Camps Bay is also the site of a marine sewage outfall (located approximately 1.5 km from the shore) that discharges 2.4 million litres of untreated sewage into the ocean on a daily basis; no industrial effluent is present in the discharge.

You can read more about a recent study done in Camps Bay on the high prevalence of herbicides in the sea water, sand and marine organisms. These studies have been widely reported on in the media herehere and here, and in the academic journals herehere and here

Microbial Pollution

What is microbial water pollution in an urban context?

Microbes are microscopic organisms that are ubiquitous in our environment. They are in us, on us and all around us, and can be beneficial or harmful. Various members of the vast array of microbiological organisms play their part in keeping nature in balance. For instance, some microbes are essential to break down food during digestion in humans and animals so that the nutrients can be released and absorbed by the body. These are the normal microbial flora of the digestive tract. Microbes are useful in ecosystems too: they assist with the breakdown of plant material so that the nutrients can be released back into the soil.

Microbes can also cause harm — particularly through their role in causing disease. When a microbiological organism can cause disease in humans or animals, it is referred to as a pathogen. Pathogenic organisms are normal components of all ecosystems, but contamination by faecal matter poses the single biggest health risk to most people, particularly those living in poorly serviced urban areas.

All of these can be carried by untreated or poorly treated sewage leaking or spilling from poor infrastructure, or passing through poorly functioning wastewater treatment works, before being released into rivers or the ocean. Poorly constructed or maintained landfill sites can also release pathogens into the environment. Disease-causing microorganisms released into the environment inevitably spread to plants, wildlife or human beings. Much of this spread happens via waterborne routes. Microorganisms such as intense algal blooms can also reduce the amount of oxygen in lakes or streams, and causing harm to animal and plant life.

Worldwide, microbial contamination of water is an ever-present problem. Environmental contamination by human and animal pathogens can be transmitted via polluted water to soil. Fresh produce irrigated by contaminated water can infect people, and contribute to person-to-person transmission once someone has been infected. These multiple pathways of transmission and infection make the identification of the original source of the pathogen difficult, especially since the vast majority of infections do not produce symptoms immediately. People are not always aware of all the contacts and exposures that they have had during the previous few days. A source of contamination may only be identified after a number of people acquired the infection. Thus control of waterborne infections depends heavily on the availability of properly designed and maintained systems to dispose of urban waste.

Buffalo River Sewage

Microbial pathogens found in wastewater

The most common human microbial pathogens found in wastewater are enteric in origin (relating to or occurring in the intestines). Enteric pathogens enter the environment in the faeces from the hosts — either animal or human — and flow into water either directly through defecation into water, contamination with sewage leaking directly into the water source or through run-off from soil and other land surfaces.

The types of enteric pathogens that can be found in water include viruses, bacteria, protozoa and helminths. Viruses do not replicate in the environment (outside their hosts) but can survive under certain conditions, until they are ingested by a host. Survival and multiplication or regrowth of bacteria in contaminated water depends mainly on the type of organism, the chemical and biological environmental conditions, the presence of competing microorganisms and the available nutrients. Thus, what may under one set of circumstances be a ‘safe’ concentration of pathogens can change into a risk when the circumstances change.

Pathogens released into water from skin or hair, wounds, pustules, urine, mucus, saliva and sputum and blood can also be transmitted. Infections are generally contracted by drinking contaminated water, recreational exposure to contaminated water, inhaling contaminated aerosols, ingesting seafood from contaminated water, or consuming raw food irrigated by contaminated water or organisms transmitted in the process of preparing food. The most common symptom of waterborne disease is diarrhoea. Diarrhoea is a symptom accompanying many diseases or other health conditions and is a health hazard in its own right.

Most of the diseases and deaths associated with water-related diseases — particularly in poorer parts of the urban space — infect people through:

  • Ingestion of pathogens in water polluted by human or animal waste (faeces). Diseases in this category include for example cholera (Vibrio cholerae), shigellosis (dysentery caused mainly by Shigella spp. or Entamoeba histolytica), typhoid (Samonella typhi), paratyphoid (Samonella paratyphi), diarrhoea (mainly Escherichia coli or viruses such as rotavirus or norovirus), or hepatitis (Hepatitis A, E).
  • Diseases associated with the lack of water to maintain personal hygiene, cleaning of clothes and cooking utensils, etc. or with contaminated water as the only water source available to the community. Diseases in this category include diarrhoea from various causes; skin and eye infections; scabies, etc.
  • Diseases associated with ingestion or penetration of the skin by infections acquired from snails, fish or other aquatic animals. These diseases include schistosomiasis and diseases that are called ‘neglected tropical diseases’. As the name implies, they occur mainly in tropical and subtropical climates.
  • Diseases that are transmitted by insects that breed in water (particularly in stagnant or contaminated water). Such diseases include malaria, dengue and yellow fever. These diseases are also climate-related: they occur mainly in tropical and subtropical climates.

The diseases listed under the last two bullet points do not occur in the City of Cape Town, but are given here for the sake of completeness as some of these diseases do occur in other parts of South Africa.

Challenges in handling urban waste streams

Urban wastewater streams can be divided by source into stormwater, sewage, domestic greywater and industrial wastewater. Each one of these sources of wastewater will contain a range of pathogens. This range depends on a large number of factors, which include:

  • the range of pathogens found in the inhabitants of the area (wastewater reflects the disease profile of the area),
  • average household composition,
  • housing infrastructure (particularly the sanitation arrangements),
  • the health status of the inhabitants,
  • the lifestyles and products used and
  • the willingness to adhere to safe household hygiene.

After wastewater leaves individual properties it enters the municipal sewage system. There is ample evidence that such systems in almost all South African towns and cities are in a dilapidated state due to years of poor maintenance, underfunding and lack of skilled supervision. Leaks and spills of sewage due to broken or blocked systems are a common sight in many streets.

Piped sewage systems should deliver the wastewater to a proper wastewater treatment works, where the water is treated to reduce microbes to safe levels. The most recent information regarding the state of wastewater treatment works in South Africa was published in 2013, when it was found that less than 10% of the 824 formal wastewater treatment works were delivering treated effluent of an acceptable standard into the environment. Most wastewater treatment works receive more wastewater than they are designed to treat, and many are poorly maintained and underfunded. All these spills and poorly treated effluent eventually make their way into the ocean.

Apart from the poorly functioning sewage systems, a large part of the City of Cape Town does not have any formal wastewater treatment facility at all. The sewage is subjected to superficial pre-treatment and then released directly into the ocean via marine sewage outfall pipes. Nearly 50 million litres of raw sewage is released into the ocean in this way every day. Read more about marine outfalls here.

“Every sewage treatment works is built close to a river because the effluent – which is meant to be clean – is returned to nature. That, by definition, is how they work all over the world. But, what is happening in many of these treatment works is that the poorly treated, contaminated effluent is being pumped into the rivers” Jo Barnes, epidemiologist

Algal Blooms and risks

When high levels of microbial pollution exists in water, phytoplankton or blue-green algae grow quickly, feeding on the nutrients from the pollution. Blue-green algae are cyanobacteria, a type of bacteria with attributes of both bacteria and algae. These cyanobacteria can be found in almost all water systems such as dams, rivers and oceans, and can appear individually or in groups.

In the right conditions, blue-green algae can grow rapidly and form visible blooms, or scums. Blooms are usually somewhere between dark green and yellowish brown, and can turn the surrounding water green. These blooms occur when there are large amounts of nutrients to support the development of huge numbers of the algae. This occurs in waters that are contaminated with untreated or poorly treated human sewage, animal manure or fertiliser runoff. It is referred to as eutrophication, or more accurately hypertrophication. This is the ecosystem response to the addition of artificial or natural substances, such as nitrates and phosphates, through fertilisers or sewage to an aquatic system.

Blooms generally occur during summer and autumn, when nutrient levels are high, temperatures are warm, and the water is relatively still. Weather conditions, nutrient levels and water flow will affect how long a bloom lasts. These blooms often surround the Cape Peninsula and are visible from space, due to their extent.

Satellite imagery indicating high chlorophyll values (in red) in False Bay around Cape Town. (Silvia Inés Romero, SHN-UBA-UNDEF Argentina)

Satellite Images of phytoplankton / algal bloom in False Bay in 2018 (Silvia Inés Romero, SHN-UBA-UNDEF Argentina)

Water affected by blue-green algae may not be suitable for drinking, recreation or agricultural use. Human contact with these blooms can cause illness such as hay fever-like symptoms, skin rashes, eye irritations, vomiting, gastroenteritis, diarrhoea, fever and pains in muscles and joints. Effects of algal blooms on water bodies can include hypoxia (the depletion of oxygen in the water), which when severe, will cause die-off of specific fish and other animal populations.

Some species of blue-green algae produce harmful toxins which can have serious health effects, when eaten, inhaled or skin contact is made. Ingesting toxins by eating contaminated species can also cause gastroenteritis symptoms, such as vomiting, diarrhoea, fever and headaches. Toxins can also have a damaging effect on the liver and the nervous system. In extreme cases death can result.

Avoid contact with algae-affected water and organisms, particularly in areas with visible scums or discoloured water. Follow the advice on any nearby signs and keep out of the water until authorities advise that the risk has passed.

If you come into contact with contaminated water, you should remove any affected clothing and wash yourself thoroughly with clean water. Always wash any contaminated clothes thoroughly with clean water before wearing it again. Affected wetsuits should be rinsed in fresh water to remove any trace of algae. If you feel sick, see a doctor.

Plastic Pollution

Marine plastic pollution is generally accepted as one of the biggest environmental problems that we are facing today. Each year, an estimated 8 million tonnes of plastic end up in the ocean. Plastic gets into the ocean through run-off and dumping. The Great Pacific Garbage Patch — between Hawaii and California is the most well researched, but there are many more in different parts of the oceans. These oceanic garbage patches are areas where debris accumulates and our seas contain large patches of clearly visible plastic junk, which breaks down into tiny microplastics.

Apart from being a terrible sight, plastics in the ocean are also a danger to marine life, sea birds and some terrestrial organisms. Plastics can cause the death of many organisms through starvation, suffocation and entanglements. Single-use plastic mainly made to last a few hours is the major culprit, causing general litter on land which is washed into the seas by rivers — cruise ships and other activities such as fishing are also main causes of plastic pollution. These single-use items are often accidentally consumed by many marine mammals. Underwater, plastic bags resemble jellyfish, a common food for sea turtles, while some seabirds eat plastic because it releases a chemical that makes it smell like its natural food. Discarded fishing nets drift for years, ensnaring fish and mammals. Shiny chips packets may look like delicious shiny fish, to a dolphin or an orca.

Marine plastic pollution is generally accepted as one of the biggest environmental problems that we are facing today. Each year, an estimated 8 million tonnes of plastic end up in the ocean. Plastic gets into the ocean through run-off and dumping. The Great Pacific Garbage Patch — between Hawaii and California is the most well researched, but there are many more in different parts of the oceans. These oceanic garbage patches are areas where debris accumulates and our seas contain large patches of clearly visible plastic junk, which breaks down into tiny microplastics.

Apart from being a terrible sight, plastics in the ocean are also a danger to marine life, sea birds and some terrestrial organisms. Plastics can cause the death of many organisms through starvation, suffocation and entanglements. Single-use plastic mainly made to last a few hours is the major culprit, causing general litter on land which is washed into the seas by rivers — cruise ships and other activities such as fishing are also main causes of plastic pollution. These single-use items are often accidentally consumed by many marine mammals. Underwater, plastic bags resemble jellyfish, a common food for sea turtles, while some seabirds eat plastic because it releases a chemical that makes it smell like its natural food. Discarded fishing nets drift for years, ensnaring fish and mammals. Shiny chips packets may look like delicious shiny fish, to a dolphin or an orca.

“There are many different kinds of plastics out in the ocean and they come from a number of different sources. So, there are teeny, tiny microplastics out there that were either manufactured to be small — for example, the microbeads in face wash can be plastic; there are also little, tiny plastic pellets that we sometimes call ‘‘nurdles’ that are used to make larger items but then there are also tiny plastics that are shards of larger items. Plastics never really go away. They just break down over and over and over again until they become smaller and smaller from sunlight and other environmental factors [like] waves, big storms, those kinds of things”. Dianna Parker, NOAA’s National Ocean Service

Source: National Oceanic and Atmospheric Administration (NOAA), US and Woods Hole Sea Grant

Scientists found plastic fibres in corals in the Atlantic Ocean—and more concerning, they found that the corals readily ate plastic over food. Dying marine mammals and birds and turtles, washing up on shore, also contain plastic inside their stomachs, and ocean plastic is estimated to kill millions of marine animals every year. Nearly 700 species, including endangered ones, are known to have been affected by it. Some are harmed visibly—strangled by abandoned fishing nets or discarded six-pack rings. Many more are probably harmed invisibly. Marine species of all sizes, from zooplankton to whales, now eat microplastics, the bits smaller than one-fifth of an inch across. Read more here.

Plastic – A Toxic Combination

Plastic is a word used to describe a variety of diverse chemical mixtures, including some additives that are used to give them certain characteristics such as colour, reduced flammability or increased flexibility. Other chemicals might end up in the plastic unintentionally during production such as per- or poly-fluorinated alkyl substances (PFAS). Read more here.

Plastics are also dangerous because they may be difficult to recycle and may contain toxic chemicals like PVC used in construction, or are likely to absorb other pollutants. Furthermore, efforts to recycle plastics may cause other problems since recycling involves burning and use of energy which can generate other pollutants and greenhouse gases.

A study on possible effects of microplastics noted that the transfer rate of pollutants in the environment increases in an organism that swallowed plastic particles, thus microplastics may raise the bioavailability of other pollutants in the food chain. Plastic debris in the ocean incorporates a cocktail of chemicals, including those added during manufacturing and those present in the marine environment. This causes several concerns such as how the complex mixture of substances may affect different species which ingest them and the fate of the environment which has these toxins.

A study on the toxic effects of plastics, found that materials commonly known as BPA – a monomeric building block produced by plastic and accelerated by repeated washing or heating released from the food or beverage containers into our food. BPA acts as a hormone through mimicking oestrogen leading to many health problems.

Plastic in our Bodies

There is loads of evidence that exposure to plastics damages health. Plastics include endocrine disrupting chemicals, often used to make plastic clear and durable, that are associated with a disruption in fertility cycles, delayed neurodevelopment in children, immune disorders, and a higher risk of hormone-related cancers. Endocrine disrupting chemicals also affect thyroid function and metabolism, and are found widely in human breast milk.

Microplastics enter foods; plastic microfibers are present in the air we breathe, the clothes we wear, and even the water we drink. We must work together for a clean environment.

Recognising how much plastic is in your life is the first step. How much plastic have you come into contact with today? Your clothes, toothbrush, and razor are probably plastic. So are most keyboards. Are your glasses plastic? If you’re wearing makeup, it probably contains plastic ingredients, especially if it’s waterproof. What do you store food in? What are your carpets made of? Is the paint in your home plastic-based?

  • The Plastic Health Coalition aims to help consumers reduce plastic consumption
  • This interactive UN website helps you identify what’s in your personal care products and cosmetics

The most important thing is to train yourself to see the plastic around you and take action: pick it up; put it somewhere else; choose not to accept it. We have all learned, all our lives, that plastic will disappear. It doesn’t.

The best way to learn to see plastic? Join a beach clean up, or a river clean up. Environmental Humanities South researcher Ingrid Sinclair, who works for the Two Oceans Aquarium, found in her dissertation that joining a beach clean up was the most effective way to help consumers reduce plastics in everyday life.

What else can be done?
Find out here >