Bveledzani Pertunia Makhado

South Africa is faced with many social development challenges such as safe water, clean energy and delivery of health services. With the increase in population, comes an increase in the demand for clean water. Currently, researchers are considering the application of nanostructured materials for water purification processes. Nanomaterials have gained significant attention in water treatment applications because of the benefits they offer. They can transform the filtration process towards cleaner and safer drinking water by removing numerous impurities. 

Nanomaterials are tiny particles, often smaller than the width of a human hair. Their size is measured in nanometers—a billionth of a meter. This minute size gives them unique properties, making them incredibly effective in water treatment. For instance, their large surface area relative to their volume allows them to capture and neutralize harmful contaminants in water, including heavy metals, bacteria, and viruses with greater efficiency than traditional methods such as chlorination, Ozonation, UV radiation. These nanomaterials can adsorb and eliminate contaminants from water, resulting in cleaner and safer water. In addition, nanotechnology can be used to construct improved filtration systems capable of removing even microscopic particles and germs from wastewater. 

Despite their impressive benefits, nanomaterials come with significant safety concerns. One of the primary concerns is that these tiny particles might be released from the filtration membranes and enter the water supply, which could be dangerous if the materials are toxic. The possibility of these nanomaterials being released during the filtration process poses a health concern due to the knowledge gap regarding the toxicity of nanomaterials to humans and other organisms. 

Reports have shown that some nanomaterials are hazardous, while others are not. The toxicity of nanomaterials is influenced by their chemical composition. Understanding the toxic effects of these nanomaterials is crucial for understanding associated risks and formulating appropriate regulations and guidelines for their safe application and monitoring in wastewater treatment.

Scientists often overlook the side effects of the use of nanomaterials in water filtration processes, but it is essential to avoid secondary pollution. There has been a lack of research in this area, possibly due to the focus on short-term experiments performed on membranes that have not yet been applied at a commercial scale. Therefore, the research focus may need to shift to studying the release of nanoparticles from water filtration membranes, as well as the resulting environmental effects and risks to human health once these membranes are commercialized. 

To address these concerns, scientists and regulatory agencies are working to develop guidelines for the safe use of nanomaterials in water treatment. They use advanced techniques such as mass spectroscopy, UV-Vis spectrometry, and electron microscopy to study how these nanomaterials interact with pollutants and detect any potential leakage of nanoparticles into the filtered water and their toxic effect on human health and the environment. Organizations such as the Organization for Economic Co-operation and Development (OECD) and the International Organization for Standardization (ISO) are involved in setting safety standards. These standards help ensure that any exposure to nanoparticles remains within safe limits, protecting public health. 

Understanding the toxicological effects of nanomaterials is important for implementing and monitoring their use in various industries. This helps ensure their safe utilization and minimizes potential adverse effects. Understanding these effects also plays a key role in developing safer and more efficient methods for incorporating these materials into wastewater treatment processes. Continued research and regulation are crucial in ensuring the safe and responsible use of nanomaterials. As our understanding of the potential risks and benefits of these materials deepens, we can develop more effective and safer water treatment solutions. Through responsible research and regulation, we can fully exploit the potential of nanotechnology, creating a safer and healthier future for everyone. My research examines the release of nanomaterials from water filtration membranes during membrane fabrication, cleaning, and water filtration and how they can be optimized for safer and more efficient water treatment. We also investigate the toxicological effects of these nanomaterials on human health using in vitro studies. This work aims to contribute to the development of safer and more effective water treatment technologies that harness the benefits of nanomaterials while mitigating their risks. 

Cassia Holtz

If you are anything like me, and you read, watch, or listen to the news, you will have heard a lot about climate change in the past few years. This is one of the most pressing topics of our time. However, much of this news is international and far away: bushfires in Australia, ice sheets melting in the Arctic, droughts, flooding, and sea level rise. But what does climate change look like in South Africa? And how do we know this? 

For context, I am a Master of Science student in Geography at the University of the Witwatersrand, Johannesburg. My field of research is exploring the health effects of climate change. Broadly, I work in biometeorology, which examines the intersections between biology and climate science. 

The largest measurable effect of climate change in South Africa is how much warmer our country is getting. Many studies have analysed data from weather stations and found that our beautiful country is getting both warmer and drier. Both the total number of warm days and the maximum daily temperature have been increasing since the 1960s. In fact, globally, the last twelve months have all broken previous high temperature records. This is concerning. 

This warming trend is also causing seasonal events to occur differently than they have been. For example: 

1. In Gauteng, Jacaranda trees have been flowering earlier in the spring, at a rate of 2.1 days per decade since 1927. 
2. The Namaqualand daisies are also reaching their first flowering earlier, by about 2.6 days earlier per decade since 1935. 
3. And in the animal kingdom, brown-veined white butterflies are migrating 2.9 days earlier per decade since 1914. 
4. South African apple and pear orchards are also advancing in blooming by 1-4 days per decade. 
5. Conversely, the Sardine Run along the east coast of South Africa has seen delays of 1.3 days per decade since 1946. 

So, what? Why does it matter that seasonal events like these happen at different times? The main reason is that these are a direct result of a warming climate. It affects the tourism sector like tours of the Namaqualand daisies, which must be organised months in advance. This also drastically affects our agricultural sector, which relies on rainfall. If trees grow and flower earlier in the spring season before the necessary rainfall has come, fruit may never grow or ripen. 

But how do we know that these things are changing? Who knows on which day the Jacaranda flowers started blooming in 1976? Well, in the absence of official records on these phenomena, we use proxies. One way that we do this is by exploring newspaper archives. South Africa has several long-running newspapers that have reported daily across the country like the discontinued Rand Daily Mail or more currently, The Star. Through some incredible digitised archives, we can look through all the old editions of these newspapers and find when they reported on Jacarandas in bloom, butterflies arriving in Johannesburg, or the great sardine run event. For example, during my Honours research last year I used newspaper archives to reconstruct the historical timing of the influenza season in South Africa between 1904 and 2019 so we can better understand the flu season. I have carried this method of research through into my Master’s where I am looking at heat waves. 

While I am describing climate change in South Africa, it is important to know that this research is also being done all over the world for other local climates and their changes. This research from across the globe is collected by the Intergovernmental Panel on Climate Change or IPCC. This United Nations panel’s main work is to compile climate change research into reports for scientists and policy makers to share both the risks of climate change as well as adaptation strategies. If you want to read more about climate change and future projections for different places in the world, the IPCC’s Sixth Assessment Report was published last year and is available online for free. The South African climate is changing and it will affect all of us. 

This post is not aimed at spelling out doom and gloom, but rather to share with you the scientific observations of what has already changed so that each of us can have a better understanding of what climate change in South Africa already looks like. We can measure the increasing heat, the drier rainfall seasons, changes in the migration of butterflies, and earlier flowering of both Jacaranda trees, Namaqualand daisies, apple and pear orchards and the timing of the Sardine Run. So next time someone makes an off-hand comment about how climate change is not a problem for today, you can point them to the fact that our country has already seen a lot of changes.