Johannesburg – We have a love affair with carbon in many of its forms, particularly diamonds and coal, but I believe that carbon is one of the world’s most problematic elements.
By now, we should be aware of the issue with carbon in the form of carbon dioxide, which drives climate change.
That carbon dioxide emissions are intimately tied to coal burning for our energy needs cannot have escaped the attention of South Africans.
Carbon-based organic chemicals are another form of carbon that we love, yet these “forever” chemicals and their impact are largely unrecognised.
Large tons of these chemicals are used in cleaning materials, medicines, personal care products, pesticides, herbicides and so on.
Everyday, we use such products to make our lives more comfortable, without understanding that the chemicals they contain are designed for stability, and are generally toxic, durable and persistent.
They do not simply disappear after use; they reappear in unexpected places.
We practise chemical warfare against mosquitoes, cockroaches, ants and flies without realising that these poisonous chemical sprays contaminate our food, linen, furniture and hard surfaces.
We somehow believe we are cleaner through using chemicals to bathe and wash clothing.
We brush our teeth with toothpastes containing synthetic chemicals and wash our plates and hands with compounds designed to kill bacteria. We certainly do not need to kill 99% of household germs with chemicals.
The carbon-based structures of these chemicals are robust.
Pharmaceuticals are designed to endure stomach acid and are mostly excreted in human waste.
When we dispose of them through our drains and toilets, they do not break up immediately, but travel via sewers and escape through wastewater treatment plants into rivers, vleis and dams.
Ultimately, these chemicals end up in the ocean, polluting it with a large diversity of synthetic compounds that take long periods to degrade.
Our studies have found that fish caught in False Bay and wild mussels harvested all around the Cape Peninsula are contaminated with numerous carbon-based chemicals.
We found pharmaceuticals that could only have come from our poorly treated faecal matter in seawater and sediments contaminating marine organisms living in every nook and cranny of the False Bay coastline.
We identified and quantified compounds such as acetaminophen, used in painkillers; diclofenac, used for relieving sore muscles; sulfamethoxazole, an antibiotic; triclosan, a disinfectant; and many other chemicals in fish and diverse marine species.
Marine organisms and fish have no choice but to live in the sea and every gill-full of seawater siphoned for oxygen leaves its chemical load behind in fish and other gill-breathing organisms and filter feeders.
Moreover, their food is also contaminated with these chemicals and, as a consequence, so is ours.
These compounds are metabolically active and useful in treating diseases, but can cause serious side effects in the form of cancer, endocrine disruption, birth defects and feminisation.
They certainly have no business in marine organisms, causing chronic toxicity, a slow death sentence for our coastal biodiversity.
One by one, these organisms are quietly dying out, gradually turning our coastal environment into an uninhabited desert.
We have already choked the ocean with plastics. Chemical pollution is far worse, as it is invisible and much more toxic than plastic.
Nevertheless, the scale of the carbon-based chemical pollution problem is growing.
To minimise our daily chemical footprint, we could make wiser choices, for instance, using biodegradable products as far as possible, collectively obliging supermarkets and other retail outlets to stock less toxic alternatives.
Our daily choices, when magnified by millions of people in our teeming cities, overwhelm the capacity of our natural systems to assimilate chemical pollution.
These carbon-based, synthetic chemicals found in sewage come back to us in our food and water, chronically damaging our food chain and health.
- Petrik, Emeritus Professor of Chemistry, University of the Western Cape, is a recognised award-winning scientist with expertise in the field of materials science, nanotechnology,
water science, water treatment, and environmental remediation.
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