Pesticides are an important tool for maintaining and improving the global population’s standard of living. However, their presence in water resources is concerning due to their potential consequences. Twelve water samples from rivers, dams/reservoirs, and treated drinking water were collected from Mangaung Metropolitan Municipality in South Africa. The collected samples were analysed using high-performance liquid chromatography linked to a QTRAP hybrid triple quadrupole ion trap mass spectrometer. The ecological and human health risks were assessed by risk quotient and human health risk assessment methods, respectively. Herbicides, such as atrazine, metolachlor, simazine and terbuthylazine, were analysed in water sources. The average concentrations of simazine in rivers (1.82 mg/L), dams/reservoirs (0.12 mg/L), and treated drinking water (0.03 mg/L) were remarkable among all four herbicides detected. Simazine, atrazine, and terbuthylazine posed high ecological risks for both acute and chronic toxicity in all water sources. Moreover, simazine is the only contaminant in the river water that poses a medium carcinogenic risk to adult. It can be concluded that the level of herbicide detected in water sources may affect aquatic life and human beings negatively. This study may aid in the development of pesticide pollution management and risk reduction strategies within the municipality.

The overpopulation of urban centres accelerates land use patterns, slum creation and generation of contaminants. As such, this study seeks to investigate the impact of rapid urbanisation on climate variability and surface water quality around Mangaung metropolis. Remote sensing was employed to analyse land use land cover (LULC), normalized differential vegetation index (NDVI) and normalized differential water index (NDWI) changes for a period of 30 years in the Mangaung metropolis. Furthermore, the historical water quality of important rivers and dams were studied in respect of urban contamination. LULC revealed that the urban areas increased exponentially which led to increased loss of vegetation cover and shortage of water availability. The rainfall and water type evolution suggests the influence of urbanisation. This suggests urbanisation accelerates the loss of vegetation cover, thus causing an increase in temperature and reduction in the amount of rainfall, thereby reducing the surface water quantity in the study area.

Introduction: Emerging contaminants are present in the water and need to be monitored and managed as they are of major environmental and health concern universally. Exposure to emerging contaminants in water sources can pose a significant risk to both aquatic species and human health. This study assessed the risks of emerging contaminants in urban and natural water sources. Methods: A high-performance liquid chromatography connected to a hybrid triple quadrupole ion trap mass spectrometer was used to analyse the targeted emerging contaminants. The ecological and human health risk assessment methods were used to assess the possible risks of contaminants. Results: Emerging contaminants such as 17-ethinyl-estradiol, simazine, ibuprofen, atrazine, carbamazepine, terbuthylazine, and metolachlor showed the possibility of high ecological risks to aquatic species. Risk mixture values in all water sources showed that the aquatic species are at high risk in all seasons. The non-carcinogenic risk of all selected herbicides in all water sources showed risk quotient values below 1 for the entire population, signifying that the population is safe. Atrazine is the only contaminant that showed high carcinogenic risk to the adult group in river water during the summer season. Conclusion: It can be concluded that aquatic species and public health are at risk. The outcomes of the study may aid in the development of environmental quality standards for regulatory and environmental sustainability purposes