Detection and quantification of emerging contaminants in Mgeni and Msunduzi rivers by gas chromatography-mass spectrometry in KwaZulu-Natal, South Africa.

Abstract

This work concerns the development, optimization and validation of simple and affordable analytical methods for determination of different classes of emerging contaminants in environmental waters and solids. Occurrence of emerging contaminants in the African environment has received much attention recently. However, there is paucity of detailed analytical methods for determination and regulation of emerging contaminants in the environment and wastewater effluents in South Africa today some parts of the world. The developed methods included, extraction with solid phase (clean-up), ultrasound-centrifuge assisted extraction (sediments), detection with gas chromatography-mass spectrometry (after derivatization of polar analytes) and ecological risk assessment technique associated with emerging contaminants. For all developed methods, recoveries (60% - 130%), R2 (> 0.99) and precisions (< 25%) within acceptable limits were achieved. This study was undertaken to determine the occurrence and concentration of major classes of emerging contaminants (pharmaceuticals, personal care products and stimulants) between 2014 and 2016 in Mgeni and Msunduzi Rivers, KwaZulu-Natal, South Africa. Surface water, wastewater (influent and effluent), sediment and biosolid samples were collected from these rivers and wastewater treatment plants along both rivers. The developed methods were combined and applied to qualitative and quantitative analysis of pharmaceuticals (acidic/ non-steroidal antiinflammatory drugs, antibiotic and hormones), stimulants (caffeine) and personal care products (paraben and triclosan). Approximately 50 emerging contaminants of different classes were detected and only 15 were quantified. Environmental concentration of contaminants were found to range from 0.02 μg L-1 to 68 μg L-1 and 0.12 to 220 ng g-1 in water and sediments respectively. Acidic drugs, antibiotic and hormones were detected in all samples analysed in both water and sediments, however, stimulant and PPC were not detected in some of the samples. Wastewater treatment plants were recognised as one of the main routes of emerging contaminants into the aquatic environment. The developed methods can be used to monitor emerging contaminants in the environment.