A new scientific review has found that perfluorooctane sulfonate, a persistent chemical pollutant known as PFOS, is accumulating in soils and agricultural plants across Africa at levels that may pose ecological and public health risks. The study highlights contamination hotspots in Ghana, South Africa, Kenya, and Uganda, and calls for urgent investment in monitoring, regulation, and research capacity across the continent.
PFOS is a member of the larger family of per and polyfluoroalkyl substances, often referred to as forever chemicals due to their extreme resistance to environmental degradation. Although PFOS has been phased out in many parts of the world, the new review shows that legacy contamination, ongoing industrial activities, electronic waste processing, wastewater irrigation, and biosolid application continue to introduce PFOS into agricultural landscapes across Africa.
"Our goal was to bring attention to a silent environmental challenge that has largely gone unnoticed in Africa," said lead author Bonface Oginga. "The soil and plant systems that support food production are already under stress. The presence of PFOS adds another layer of pressure that countries are not adequately equipped to monitor or manage."
According to the analysis, PFOS concentrations in African soils reach as high as 275.3 ng per gram in Ghana and 248.14 ng per gram in South Africa. These levels exceed those reported in many regions of the world and indicate significant localized sources such as e waste dumpsites, industrial zones, and wastewater discharge areas. Sewage sludge from one facility in Ghana contained PFOS concentrations greater than 200 ng per gram, far higher than levels recommended by regulatory agencies in other countries. When such sludge is used as fertilizer, PFOS can enter cropland and eventually food crops.
The review also examined PFOS in agricultural plants and revealed that multiple staple crops grown across Africa contain detectable levels of the contaminant. Leafy vegetables show the highest accumulation, while crops like sugarcane, yams, and maize also take up PFOS from contaminated water or soils. In Kenya, one plant sample contained 29.33 ng per gram, marking the highest plant concentration reported to date on the continent. Because PFOS binds strongly to soil particles, uptake into plants depends on soil conditions such as organic matter content, acidity, and mineral composition. Many African soils are low in organic matter and slightly acidic, which increases the mobility and bioavailability of PFOS.
"Food crops are a direct pathway through which PFOS can reach human populations," said co author Fredrick Owino Gudda. "Understanding how PFOS enters and moves through the soil and plant system is essential for assessing the risks to communities that depend on local agriculture."
The study describes broader ecological impacts as well. PFOS exposure can disrupt soil microbial communities, alter enzyme activity, and interfere with plant nutrient transport systems. In regions where phosphorus and nitrogen deficiencies are already widespread, PFOS related stress may further reduce crop productivity. The authors warn that without coordinated action, PFOS contamination could undermine food security, soil health, and ecosystem stability in vulnerable regions.
The review urges African governments and environmental agencies to expand monitoring programs, adopt advanced analytical technologies, and develop continent specific regulations for PFAS chemicals. The authors also emphasize the importance of regional collaboration and the need for investment in scientific capacity, including training, laboratory infrastructure, and long term environmental datasets.
"This review is a call for action," said senior author Chao Qin. "By strengthening monitoring, regulation, and research, African countries can better protect their soils, crops, and communities from the long term risks posed by PFOS."
The authors conclude that addressing PFOS contamination will require both scientific innovation and policy leadership, especially in rapidly industrializing regions where chemical pollution is expected to increase in the coming decades.
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Journal reference: Oginga B, Gudda FO, Ibrahim A, Li Z, Minkina T, et al. 2025. Perflourooctane sulfonate in soil–plant systems in Africa: occurrence and ecological risks. New Contaminants 1: e015
https://www.maxapress.com/article/doi/10.48130/newcontam-0025-0015
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About the Journal:
New Contaminants is an open-access journal focusing on research related to emerging pollutants and their remediation.
