WRC studies CECs like microplastics and ARVs in SA water to guide safety standards and improve treatment strategies.
The Water Research Commission (WRC), an entity of the Department of Water and Sanitation (DWS), along with local and international partner research organisations, has since early 2000 commissioned several studies on the presence of contaminants of emerging concern (CEC) in water resources and drinking water. The WRC’s research has focused on CECs such as microplastics, chemicals, and pharmaceuticals that could potentially pose risks to human health and the environment. These studies inform the water quality guidelines and regulations issued by DWS.
One of the studies related to anti-retrovirals (ARVs) and was undertaken by the University of North West. As reported in the media, the study found traces of ARVs in water samples taken from rivers and potable water sources.
South Africa has rolled out a massive programme to curb HIV and AIDS, including access to ARVs to reduce the risk of the onset of AIDS. As a result, traces of ARVs are entering municipal sewage systems and passing through these systems into rivers. This can be attributed to the pharmacological process where the active part of the medication is absorbed by the body, leaving the residual to be discharged from the body, subsequently finding its way into the sewage system. These traces of ARVs can then also be present in water that has been extracted from the rivers by municipalities to be treated and supplied as potable water.
Globally, CECs are increasingly recognised as a concern for water quality, especially in wastewater and reclaimed wastewater for potable reuse, as well as agricultural water uses. However, CECs are a relatively new area of research globally, particularly relating to the causes and effects of CEC, the human health risks, treatment methods to remove CECs, and potential regulatory measures that can be taken to address the problem.
The WRC research has focused on increasing understanding of the sources, pathways, and potential impacts of CECs on water resources, including:
- Identifying CECs: Determining which CECs are present in water sources.
- Understanding pathways: Investigating how CECs enter water ecosystems.
- Assessing risks: Evaluating the potential health and environmental risks associated with CECs.
- Developing treatment strategies: Exploring innovative treatment methods to remove or mitigate CECs.
The key water quality risks to human health of a biological and microbiological nature are well understood and regulated in South Africa. The South African National Standard SANS241 for water quality is based on World Health Organisation standards, ensuring that the human health risks are mitigated. This has enabled DWS to implement monitoring programmes such as the blue and green drop programmes to provide information to the public on the
performance of municipal water and wastewater systems relative to SANS241.
The traces of pharmaceuticals, microplastics and other such CECs that have been found in water resources in South Africa are very small quantities, measured in nanograms (one billionth of a gram). Conventional water and wastewater treatment technologies are designed to remove much larger contaminants such as particles of faeces and bacteria.
The study commissioned by the WRC and carried out by North West University found that:
- Almost all the concentrations in drinking water samples at the test sites were below limits of quantification. The most frequently detected compound was fluconazole (28 detections from 72 samples), with concentrations ranging between 0.06-1.8 μg/L (nanograms per litre)
- Nevirapine and efavirenz were the second most detected compounds, both with 22 detections out of 72 samples
- However, on average, lopinavir and efavirenz had the highest concentrations of the compounds analysed, while Didanosine and zidovudine were the least detected compounds (2 and 6 detections out of 72 samples).
Higher concentrations of traces of ARVs were found downstream of wastewater treatment plants. This means that the municipal wastewater treatment works are not removing them, because most existing wastewater treatment works have not been designed to remove CECs.
Low concentrations of ARVs were found in some of the drinking water samples. There is a possibility that high concentrations of ARVs in sewage or municipal wastewater might reduce the effectiveness of the wastewater treatment works in removing bacteria from the wastewater. Further research is required in this regard.
The presence of ARV residues in drinking water is harmless, although prolonged exposure to the broader population may lead to antimicrobial resistance, a subject of ongoing research. Pharmaceuticals such as ARVs are drugs used to treat diseases – they do not cause diseases. Therefore, the presence of traces of ARVs in the water will
not result in people contracting HIV.
At present, there is limited knowledge of environmental toxicity, potential adverse effects on ecosystems and viral resistance of these compounds. The study did not find any ARVs in fish. CECs in water is a growing global problem and area of attention around the world. Globally, the level of CEC compounds in water is generally not yet regulated.
This is partly due to their presence often being below water quality detection limits. However, due to their continuous production, lack of appropriate disposal, constant input into the environment and presence in water resources, albeit in small concentrations, there is now increasing global research into the issue.
Development of methods and techniques to trace these elements accurately in water is one of the key focus areas of global research. Research is also being carried out into effective methods of treatment of the problem, including advanced membrane systems.
To access the report, Quantification, fate, and hazard assessment of HIV-ARVs in water resources (WRC report no. 2594/1/19), visit: https://www.wrc.org.za/wpcontent/uploads/mdocs/2594%20-%20Volume%201.pdf
https://www.wrc.org.za/wp-content/uploads/mdocs/2594%20-%20Volume%202.pdf
Evaluating the removal of contaminants of emerging concern in drinking water and wastewater treatment systems : Link: https://wrcwebsite.azurewebsites.net/wpcontent/uploads/mdocs/31661.pdf
