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Understanding PFAS behavior: analysing contamination patterns in surface water and sediment of the apies river, South Africa
(Springer, 2025) Petrik, Leslie Felicia; Okwuosa, Raissa; Nomngongo, Philiswa Nosizo
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.
Functionalized polyethylene terephthalate nanofiber adsorbents for prospective metal recovery from spent lithium-ion batteries
(Springer, 2025) Tshisano, Kamogelo; Mukaba, Jean-Luc; Pereao, Omoniyi Kolawole; Mouele, Emile Salomon Massima; Petrik, Leslie Felicia
The lack of economically viable and environmentally friendly recycling processes to recover valuable metals from spent lithium-ion batteries (LIBs) has resulted in an environmental pollution and a high risk of metal resource shortage. Among various approaches, adsorption using electrospun nanofiber adsorbents has attracted research interest due to several distinctive properties. This study synthesized electrospun polyethylene terephthalate (PET) nanofiber adsorbent which was functionalized with Di-2-ethylhexyl phosphoric acid (DEHPA) to recover Ni, Co, or Mn metal ions. The pristine and modified electrospun nanofibers were characterized using Fourier Transform Infrared spectroscopy (FTIR)-Attenuated Total Reflection (ATR), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Thermogravimetric Analysis (TGA), and X-ray Diffraction (XRD). The adsorption kinetics and capacity of the modified PET-DEHPA nanofibers were obtained at optimum pH 4; 60 min of contact time and 100 mg/L initial metal concentration. The adsorption capacity of PET-DEHPA nanofibers for Ni, Co and Mn metal ions was 80 mg/g, 98 mg/g, and 118 mg/g, respectively. The selectivity of Mn over Ni and Co metal ions was also examined at pH 4 and showed that the recovery efficiencies were 5%; 11% and 58% for Ni, Co and Mn, respectively. Thus, indicating that the modified PET-DEHPA nanofiber was selective for Mn ions. The desorption and regeneration were also studied in solutions of nitric acid and Ni, Co and Mn ions, and results showed that PET-DEHPA nanofiber was able to withstand over 5 cycles, highlighting its potential in economic viability and sustainability. Overall, this study presents a new and promising approach for recycling Mn ions from solutions of spent LIBs.
A novel hp-growth model for enhancing community policing in South Africa
(Springer, 2025) Macingwane, Apiwe; Isafiade, Omowunmi Elizabeth
South Africa (SA) grapples with a rising crime rate, which poses challenges to the safety and economic growth of the country. Despite the limited literature on pattern-based models in SA, frequent pattern-based models, particularly Frequent Pattern Growth (FP-Growth) and Hyper Structure Mining (Hmine), have demonstrated utility in various research fields. This paper introduces a novel model, Hybrid Pattern-Growth (HP-Growth), which combines the strengths of FP-Growth and Hmine. A comparative analysis of the South African crime statistics (Stats SA crime) dataset’s computational time complexity, scalability, and memory usage revealed that HP-Growth and Hmine outperform FP-Growth. This study establishes association rule thresholds and emphasizes the importance of selecting the most appropriate pattern-based model for generating crime patterns. According to the study, HP-Growth outperformed the other two models on sparse datasets, whereas Hmine excelled on dense datasets. FP-Growth uses more memory and has a greater time complexity than HP-Growth and Hmine. The most suitable model was then integrated into the developed crime support system. The research outcome has practical implications for law enforcement in aiding strategic resource allocation and proactive policing for crime reduction and control.
Early pregnancy and motherhood among young women in Sub-Saharan African countries: analysis of trends and associated factors
(Elsevier, 2025) Mpilambo, Jacques Elengemoke; Abduraghiem, Latief; Susuman, Appunni Sathiya
This study examined the trends and factors associated with early pregnancies and motherhood among young women in three sub-Saharan African countries: Malawi, Mali, and Niger. Descriptive and multivariate analyses showed that the prevalence of early childbearing declined significantly in all three countries between 2006 and 2016. Moreover, the determinants of age at first childbearing varied across these nations. It is crucial to implement programmes that encourage delaying the age of the first sexual debut. In addition, providing adolescent women with comprehensive knowledge about responsible and safer sex practices and motherhood is paramount in addressing this challenge.
Healthcare-associated bloodstream infections caused by bacterial and fungal contamination of intravenous fluids and medicines in healthcare facilities in low- and middle-income countries: a scoping review
(Elsevier, 2025) Ravinetto, Raffaella; Nyandwaro, Jemima Nyaboke; Hyland, Peter
Introduction: We reviewed culture-confirmed healthcare-associated outbreaks linked to bacterial and fungal contamination of intravenous fluids and medicines (further “infusates”) in low-income countries and lower and upper middle-income countries (LIC, Lower-MIC and Upper-MIC). We assessed the scope, impact, risks, and gaps in knowledge. Methodology: Literature search including PubMed, Web of Science, Worldwide Database for Nosocomial Outbreaks, Global Health, and Google Scholar. National essential medicine lists (NEMLs) of sub-Saharan countries were searched for listing of pediatric infusates. Results: Between 1975 and 2023, 50 articles were retrieved. Median (range) number of patients affected was 12 (3–185); 74.2% (761/1025) of all patients affected were children. All patients presented with bloodstream infections; median case fatality ratio was 21.1% (0.0–87.5%). Upper-MIC, Lower-MIC and LIC accounted for 21, 25 and 4 articles, respectively. Most frequently affected wards were neonatal and adult intensive care units (19 and 6 articles). The 50 articles revealed 59 contaminated infusates: IV fluids (n = 37), including TPN (n = 10, of which 8 were from Upper-MIC), and IV medicines (n = 22), comprising amongst others propofol (n = 4) and Water for Injection (n = 3). The 63 isolates included Enterobacterales (46.0% (29/63) of isolates), non-fermentative Gram-negative bacteria (NFGNB, 47.6% (30/63)), fungi (4.8%, 3/63)) and Bacillus circulans (1.6% (1/63)). Among the Enterobacterales, the genera Serratia, Klebsiella, and Enterobacter represented 82.8% (24/29) of isolates. Burkholderia cepacia was the most frequent NFGNB (53.3% (16/30) isolates). Excluding TPN, 18 IV fluids and 7 IV medicines (representing half (51.0%, (25/49) of these infusates) were incorrectly used as multidose vial. A third (33.9%, 20/59) of infusates in 40.0% (20/50) of articles was intrinsically contaminated. In LIC and LMIC, staff in neonatology units turned to in-ward preparation of infusates because of lack of access to pediatric IV formulations and sizes. Less than a third (31.8%, 18/44) of the NEMLs listed neonatal IV premixtures. Conclusion: Infusate contamination is a serious, underreported risk especially for children in LICs and Lower-MIC. Outstanding issues are access to pediatric infusates and preventing in-ward preparation of IV medicines in LIC and Lower-MIC, and safe preparation and administration of TPN in Upper-MIC.