Understanding PFAS Behavior: Analysing Contamination Patterns in Surface Water and Sediment of the Apies River, South Africa
Open accessAbstract
Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants widely detected in water and sediment worldwide. Despite growing concerns about their ecological and health risks, their distribution in African aquatic environments remains understudied. This study addresses the knowledge gap in PFAS contamination by analysing the spatial and temporal distribution of 18 PFAS in Apies River water and sediment in Pretoria, South Africa. Surface water and sediment samples were collected upstream and downstream of the Apies River during dry seasons. The analysis of PFAS concentrations was conducted using liquid chromatography-tandem mass spectrometry. Statistical analysis, including paired t-tests, non-metric multidimensional scaling, and hierarchical cluster analysis, were applied to determine spatial and temporal trends. The study revealed significant spatial variations in PFAS contamination, with upstream locations consistently exhibiting higher concentrations than downstream. In surface water samples, L_PFBS, 4:2 FTS, 6:2 FTS, and L_PFHpS showed statistically significant differences ( p < 0.05) between sites. Perfluorocarboxylic acids were the dominant PFAS class in surface water (50.47–57.15%), whereas perfluorosulfonic acids were more prevalent in sediments. Upstream sediment had higher L_PFHpS (43.00 ng/g), L_PFDS (38.89 ng/g), and L_PFHxS (23.91 ng/g) than downstream (31.96, 27.84, and 18.02 ng/g, respectively). The findings reveal contamination sources and partitioning between surface water and sediments, aiding in water quality management and pollution mitigation strategies.
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
Recent studies on PFAS distribution across water-sediment compartments have mainly focused on either specific pollution sources or large watersheds, with limited attention to diffuse urban sources.
“Despite recent studies that have advanced the understanding of PFAS distribution across watersediment compartments in various settings, including in harbours [23], large river deltas [24], and urban waterways [25], these studies have mainly focused on either specific pollution sources or large watersheds, with limited attention to diffuse urban sources.”
From Land use and seasonal controls on Per- and Polyfluoroalkyl Substances (PFAS) distribution and partitioning from diffuse sources in subtropical urban waterways (2026) · cites this paper as [25]
The Materials and Methods (Sampling; page unavailable) identify the Apies River as flowing through Pretoria, and the Results and Discussion (Identifying PFAS Sources in Water and Sediment Samples; page unavailable) examine PFAS in both compartments. This supports citing the paper as an urban-waterway study. It does not establish that recent studies generally give limited attention to diffuse urban sources; the paper itself identifies urban runoff as a downstream influence. (LLM, conf=0.84)
Experimental — accuracy not yet measured
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Cites
Per- and polyfluoroalkyl substances in the environment
Evich, M. G., Davis, M. J. B., McCord, J. P., Acrey, B., Awkerman, J. A., Knappe, D. R. U., Lindstrom, A. B., Speth, T. F., Tebes-Stevens, C., Strynar, M. J., et al. (2022) · Science · doi:10.1126/science.abg9065 · Cited by 2,157 · cited 1× · see citing works
“…substances (PFAS), commonly referred to as forever chemicals, are a group of man-made synthetic chemicals that were developed in the mid-1900s (Evich et al., 2022) PFAS encompass a substantial group of fluorinated compounds that are present in certain commer - cial products and the…”
Nguyen, T. M. H., Bräunig, J., Thompson, K., Thompson, J., Kabiri, S., Navarro, D. A., Kookana, R. S., Grimison, C., Barnes, C. M., Higgins, C. P., et al. (2020) · Environmental Science & Technology · doi:10.1021/acs.est.0c05705 · Cited by 523 · see citing works
Biodegradation of Per- and Polyfluoroalkyl Substances (PFAS): A Review
Zhang, Z., Sarkar, D., Biswas, J. K., & Datta, R. (2022) · Bioresource Technology · doi:10.1016/j.biortech.2021.126223 · Cited by 353 · see citing works
Wang, D., Xiao, F., Xiao, F., Chen, J., Park, C. M., Park, C. M., Flury, M., & Flury, M. (2022) · Reviews of Geophysics · doi:10.1029/2021rg000765 · Cited by 274 · see citing works
Dalahmeh, S., Tirgani, S., Komakech, A. J., Niwagaba, C. B., & Ahrens, L. (2018) · Science of The Total Environment · doi:10.1016/j.scitotenv.2018.03.024 · Cited by 262 · see citing works
Sims, J. L., Stroski, K. M., Kim, S., Killeen, G., Ehalt, R., Simcik, M. F., & Brooks, B. W. (2022) · Science of The Total Environment · doi:10.1016/j.scitotenv.2021.151535 · Cited by 214 · see citing works
Legacy and emerging per-and polyfluoroalkyl substances (PFAS) in the Bohai Sea and its inflow rivers
Meng, L., Song, B., Zhong, H., Ma, X., Wang, Y., Ma, D., Lu, Y., Gao, W., Wang, Y., & Jiang, G. (2021) · Environment International · doi:10.1016/j.envint.2021.106735 · Cited by 164 · see citing works
Groffen, T., Wepener, V., Malherbe, W., & Bervoets, L. (2018) · The Science of The Total Environment · doi:10.1016/j.scitotenv.2018.02.023 · Cited by 162 · see citing works
Zhou, T., Li, X., Liu, H., Dong, S., Zhang, Z., Wang, Z., Li, J., Nghiem, L. D., Khan, S. J., & Wang, Q. (2024) · Journal of Hazardous Materials · doi:10.1016/j.jhazmat.2024.133637 · Cited by 154 · see citing works
Ahrens, L., Gashaw, H., Sjöholm, M., Gebrehiwot, S. G., Getahun, A., Derbe, E., Bishop, K., & Åkerblom, S. (2016) · Chemosphere · doi:10.1016/j.chemosphere.2016.09.007 · Cited by 121 · see citing works
Per- and polyfluoroalkyl substances in water and soil in wastewater-irrigated farmland in Jordan
Shigei, M., Ahrens, L., Hazaymeh, A., & Dalahmeh, S. S. (2020) · The Science of The Total Environment · doi:10.1016/j.scitotenv.2020.137057 · Cited by 102 · see citing works
Viticoski, R. L., Wang, D., Feltman, M. A., Mulabagal, V., Rogers, S. R., Blersch, D. M., & Hayworth, J. S. (2022) · Science of The Total Environment · doi:10.1016/j.scitotenv.2022.155524 · Cited by 89 · see citing works
Gao, L., Liu, J., Bao, K., Chen, N., & Meng, B. (2020) · Science of The Total Environment · doi:10.1016/j.scitotenv.2020.138753 · Cited by 77 · see citing works
Chirikona, F., Quinete, N., Gonzalez, J., Mutua, G. K., Kimosop, S. J., & Orata, F. (2022) · International Journal of Environmental Research and Public Health · doi:10.3390/ijerph19158980 · Cited by 52 · see citing works
Distribution characteristics of poly- and perfluoroalkyl substances in the Yangtze River Delta
Zheng, B., Liu, X., Guo, R., Fu, Q., Zhao, X., Wang, S., Chang, S., Wang, X., Geng, M., & Yang, G. (2017) · Journal of Environmental Sciences · doi:10.1016/j.jes.2017.09.015 · Cited by 51 · see citing works
Melake, B. A., Bervoets, L., Nkuba, B., & Groffen, T. (2021) · Environmental Research · doi:10.1016/j.envres.2021.112033 · Cited by 50 · see citing works
Ololade, I. A., Oladoja, N. A., Ololade, O. O., Oloye, F. F., Adeola, A. O., Alabi, A. B., Ademila, O., Adanigbo, P., & Bankole, O. M. (2018) · Journal of environmental chemical engineering · doi:10.1016/j.jece.2018.06.020 · Cited by 41 · see citing works
Arinaitwe, K., Keltsch, N., Taabu-Munyaho, A., Reemtsma, T., & Berger, U. (2021) · Science of the Total Environment · doi:10.1016/j.scitotenv.2021.146970 · Cited by 37 · see citing works
Novak, P. A., Hoeksema, S. D., Thompson, S. N., & Trayler, K. M. (2023) · Marine Pollution Bulletin · doi:10.1016/j.marpolbul.2023.115215 · Cited by 33 · cited 1× · see citing works
“Water bod - ies, including marine waters, estuaries, rivers, streams, and lakes, receive PFAS pollutants through various pathways such as atmospheric deposition, surface runoff, and direct discharge (Sims et al. 2022; Novak et al. 2023).”
Gerardu, T., Dijkstra, J., Beeltje, H., van Duivenbode, A. V. R., & Griffioen, J. (2022) · Environmental Advances · doi:10.1016/j.envadv.2022.100332 · Cited by 30 · see citing works
Adeogun, A. O., Chukwuka, A. V., Ibor, O. R., Asimakopoulos, A. G., Zhang, J., & Arukwe, A. (2024) · Environmental Pollution · doi:10.1016/j.envpol.2024.123575 · Cited by 29 · see citing works
Flagged first, then by citations
Cited by
Sorted by citations
Koongolla, J. B., Egodawatta, P., Goonetilleke, A., & Ayoko, G. A. (2026) · Journal of Hazardous Materials · doi:10.1016/j.jhazmat.2026.143434
- Authors
- Okwuosa, R., Nomngongo, P. N., Petrik, L., Olatunji, O. S., & Okonkwo, O. J.
- Affiliations
- Tshwane University of Technology (ZA)
- University of Johannesburg (ZA)
- University of the Western Cape (ZA)
- University of KwaZulu-Natal (ZA)
- Corresponding author
- Okwuosa, R.
- Venue
- Bulletin of Environmental Contamination and Toxicology
- Published
- 2025-03-27
- Volume
- 114
- Issue
- 4
- Pages
- 54-54
- ISSN
- 0007-4861 (ISSN-L)
- 1432-0800
- PMC
- PMC11950043
- OpenAlex
- W4408921991
- Cited by
- 10
- References
- 21
- Citations by year
- 2026: 8 · 2025: 2
- FWCI
- 2.99
- Type
- journal article
- Language
- en
- Open access
- hybrid
- doi.org
- Locations
- Bulletin of Environmental Contamination and Toxicology (publishedVersion, cc-by)
- Europe PMC (PubMed Central) (publishedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- Funders
- University of Johannesburg
- Topics
- Physical Sciences › Environmental Science › Environmental Chemistry › Per- and polyfluoroalkyl substances research
- Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Toxic Organic Pollutants Impact
- Physical Sciences › Environmental Science › Water Science and Technology › Fluoride Effects and Removal
- Keywords
- per- and polyfluoroalkyl substances, PFAS contamination, surface water, river sediments, spatiotemporal variation, perfluorocarboxylic acids, perfluorosulfonic acid, PFHxS, PFHpS, PFBS, sediment-water partitioning, pollution sources, water quality management
- MeSH terms
- Environmental Monitoring, Fluorocarbons, South Africa, Water Pollutants, Chemical, Geologic Sediments, Rivers, Tandem Mass Spectrometry
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
