Water, human beings and risks – a case of chemicals of emerging concern – Fellows’ seminar by Faith Kandie

23 February 2024

“Extensive research on the occurrence and risk posed by these contaminants has been done in developed countries with limited information especially from the African continent,” said Faith Kandie of the Department of Biological Science at Moi University, Kenya. “Evidence-based data are essential for regulators and policy makers to formulate and implement policies that lead to responsible production and consumption with the aim of protecting human and ecological integrity especially in developing countries.”

And this is a situation Kandie is determined to tackle – focusing her research on gathering as much data as possible from her own country – Kenya – on chemicals of emerging concern in freshwater systems.

“This is not a local but a global problem. There is a need for a global response.”

And good data is the starting point.

Iso Lomso Fellow Faith Kandie during her seminar on 20 February 2024

Of course, none of this is new. Kandie pointed out that pollution of the planet started in earnest with the First Industrial Revolution in the 18th century – “Some more well-known incidents include the Great Smog in London in 1952 in which 4000 were killed” – but the extent and increase in the potential contaminants have hugely exacerbated the problem.

She also pointed to the work of environmental activists like Rachel Carson who was specifically concerned about the use of DDT in the post-World War II period. “Her legacy was that then President Kennedy banned the use of DDT in the US,” explained Kandie.

“The saying ‘Water is Life’ has been used to show the importance of water in sustaining wildlife, plants and human life. With increased industrialisation and the need to feed the growing global population, water resources and services have been threatened because of indiscriminate use and disposal of a wide array of contaminants into water systems. I am focusing on a specific group of contaminants known as chemicals of emerging concern (CECs) and their potential risk to aquatic organisms and human health.”

Kandie pointed out that the United Nation’s predicts that the global population will reach 9.7 billion by 2050. This means increases in resource extraction and pollution, coupled with the increased production and consumption of chemicals. “There are 350 000 chemicals currently registered for use and production,” she explained. “There is a risk that they get into the ecosystem, atmosphere, water and soil with potential risk to all organisms including humans.”

She explained that CECs comprise a vast array of chemicals that have recently appeared in environmental matrices, have been detected at concentrations significantly higher than expected, or their risk to human and environmental health may not be fully understood. These include pharmaceuticals, industrial and household chemicals, personal-care products, pesticides and biocides, manufactured nanomaterials, microplastics and microbeads from cosmetic and cleaning products. They are usually found in very small quantities in water sources – a few nanograms per litre – but their long-term effects are not known.

CECs are introduced into the environment via production processes, human consumption and excretion, agricultural activities including application of manure, dumping of waste, and aquaculture activities.

“These chemicals are ubiquitous and persistent,” said Kandie. “They are found even in remote areas like the Arctic and Antarctic.”

And often something that’s added to improve an existing product turns out to have an unexpected impact. Kandie pointed out that chemicals added to rubber tyres to make them last longer react with ozone and have been found to cause lethality in trout and salmon. Other ecological concerns from toxic compounds include cytological changes, altered sex ratios, antimicrobial resistance and photosynthesis inhibition in organisms.

What about Africa?

“Such pollution is rarely mentioned,” said Kandie. “Most of the studies are in the US and Europe, and there is scarce or no information from Africa with countries such as South Africa, Kenya and Nigeria leading in monitoring of these contaminants.”

Kandie’s study area is the Lake Victoria Basin. She has worked in 48 sites in this area which comprises different land use including rice fields, sugarcane, maize and tea as well as different water systems including rivers, reservoirs and drainage canals.

Samples Kandie has taken from the water, biota (specifically snails) and sediment have indicated the presence of 75 components in the water with the highest in number and concentration being a locally available antibiotic. An additional 68 compounds were found in snails and sediment.

Contaminants also found included human drugs such as anti-cancer drugs and antiretrovirals used to treat HIV (HIV and breast cancer are found at a high incidence in the area), anti-inflammatories and analgesics; pesticides; as well as neonicotinoid insecticides which are banned in the European Union. Kandie has found that these compounds were potentially toxic to fish, crustaceans and algae.

“A few contaminants are driving the risk,” she said.

And the effects of all of this on other local organisms and human health are unknown. But Kandie explained the vicious circle that can develop using the example of Schistosomiasis. “Infected humans excrete eggs into a water source, they hatch and attach to a snail which then becomes an infectious agent attaching to another human host. Some pesticides pave the way for increased transmission because snail predators and competitors are affected by the pesticides, but the snails are not so there is a shift in the community composition. There has been an increase in concern globally on schistosomiasis prevalence as it has also been found in Corsica and Spain.”

Kandie is an Iso Lomso fellow and her STIAS project over the next three years is to go beyond taking samples to look at wastewater-based epidemiology. She explained that this concept was used during the COVID-19 pandemic to detect infection peaks and has also been used to determine illicit drug use in the population. Kandie’s focus is pesticides, and her aim is to monitor pesticides and pesticide metabolites in waste and surface water as an indicator of human exposure. The study will be carried out in four counties in western Kenya covering the major crop types (tea, maize, rice, wheat and flowers). Solid-phase extraction will be performed on the samples followed by liquid chromatography coupled to high-resolution mass spectrometry for identification and quantification.

Kandie concluded by emphasising the urgent need for more infrastructure development – especially water-treatment plants and sanitation facilities; for increased public awareness and training (especially for subsistence farmers); for more policy and regulation as well as their implementation in Africa; and, for multisectoral collaboration and engagement.

“There are major knowledge gaps,” she said. “You also must be very careful whose foot you are stepping on – local farmers, for example, didn’t want us to sample their water for fear of being prohibited to use their only water source. I have also met with local government officials and written blogs to try and attract attention to the issue, but we are talking about micro-pollution in levels of a nanograms per litre – there are too many other bigger problems.”

But she is hopeful. “Kenya has a strong history of environmental activism and there is growing awareness especially around hazardous pesticides and the double standards – where things banned in the EU are still sold in Africa.”

“The start is good evidence and education. Empowering one person, empowers a community.”


Michelle Galloway: Part-time media officer at STIAS
Photograph:  Noloyiso Mtembu


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