The Investigation of Emerging Contaminants along the Modder River Catchment, Free State, South Africa

Abstract

Today, human kind frequently employs a diverse range of synthetic organic compounds for household tasks, farming, industrial production, and the treatment of both human and animal health. The continuous manufacturing of new chemicals and their usages has now led to the type of pollutants recognised as emerging contaminants. Their accumulation in water sources has reduced water quality and made water risky for aquatic and human life. Consequently, this study was piloted with the aim of investigating emerging contaminants along the Modder River catchment in the Free State province. Samples were collected during the spring season using a grab sampling method from rivers (n = 5), dams (n = 5), tap water (n = 2), wastewater influent (n = 2) and wastewater effluent (n = 2). The samples were analysed using high-performance liquid chromatography connected to a hybrid triple quadrupole ion trap mass spectrometer. Sources of emerging contaminants in the Modder River catchment were determined by multivariate statistical techniques, namely Pearson correlation and hierarchical cluster analysis. Among the targeted compounds in this study., namely 17-alpha-ethinylestradiol, ampicillin, atrazine, estradiol, ibuprofen, imidacloprid, lamivudine, progesterone, simazine, terbuthylazine, testosterone, and triclosan, 17-alpha-ethinylestradiol had the utmost mean values in rivers, dams, and tap water while lamivudine had the highest average concentrations in wastewater influent and effluents. The results of multivariate statistical analysis revealed that the occurrence of emerging contaminants in water sources around the Modder River catchment is associated with wastewater effluent discharge, illegal dumping, domestic sewage overflow, stormwater runoff and agricultural runoff. This study has revealed that the Modder River catchment is vulnerable to pollution by emerging contaminants as a result of man-made activities, which may adversely affect the aquatic ecosystem. The outcomes of this study may be helpful in protecting the aquatic environment. It is recommended that wastewater treatment managers develop and implement advanced treatment technologies for the removal of emerging contaminants in their plants to avoid further impairment of the Modder River catchment.