Partition distribution of selected organochlorine pesticides in water, sediment pore water and surface sediment from uMngeni River, KwaZulu-Natal, South Africa

• Published in: Water S. A. 2018-04, Vol.44 (2), p.232-249
• Main Authors: Birungi, G., Moodley, B., Gakuba, E., Ndungu, P.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chlorine compounds; Chromatography; Climate change; DDE; Distribution; Dry weight; Endrin; Environmental aspects; Gas chromatography; Gas chromatography-mass spectrometry; Influents; Liquid-liquid extraction; Mass spectrometry; Mass spectroscopy; Nitrous oxide; Organic compounds; Organochlorine pesticides; PCB; Pesticides; Polychlorinated biphenyls; Pore water; Rivers; Scientific imaging; Sediment; Sediment samplers; Sediment samples; Sediments; Solvent extraction; Sulfuric acid; Surface water; uMngeni River; Wastewater; Wastewater treatment; Water analysis; Water pollution; Water sampling; Water treatment
• ISSN: 0378-4738
• DOI: 10.4314/wsa.v44i2.09

Organochlorine pesticides (OCPs) were analysed in surface water, pore water and surface sediment samples collected from the uMngeni River, which is one of the largest rivers in the province of KwaZulu-Natal, South Africa. Liquid-liquid extraction was used to extract the analytes from water and pore water samples and soxhlet extraction was used to extract sediment samples with subsequent florisil clean-up and gas chromatography-mass spectrometry (GC-MS) analysis. Twelve selected OCPs were analysed and their total concentrations were found to range from 8.04–21.06 ng/mL, 36.06–188.43 ng/mL and 148.17–554.73 ng/g in unfiltered surface water, unfiltered pore water and surface sediment (dry weight (dw)), respectively. The results indicated that the concentrations of these selected pesticides were far higher in sediment (72%) than in pore water (25%) and water (3%). The most polluted sites were Northern Wastewater Treatment influent (NWTI) for water (Σ12OCP = 19.41 ± 1.43 ng/mL) and Northern Wastewater Treatment effluent (NWTE) for pore water (Σ12 OCP = 166.23 ± 7.16 ng/mL) and sediment (Σ12 OCP = 495.21 ± 32.38 ng/g). The most abundant individual OCPs and their average concentrations in general in the river were p,p′-DDE in unfiltered water (1.62 ±0.22 ng/mL) and unfiltered sediment pore water (17.09 ±7.96 ng/mL), and endrin in surface sediment (55.57 ± 19.01 ng/g, dw).