title: Determination and Distribution of Polycyclic Aromatic Hydrocarbons in Rivers, Sediments and Wastewater Effluents in Vhembe District, South Africa.
abstract: Polycyclic aromatic hydrocarbons are very toxic and persistent environmental contaminants. This study was undertaken to assess the concentrations and possible sources of 16 PAHs (Polycyclic aromatic hydrocarbons) classified by the United State Environmental Protection Agency as priority pollutants in water and sediments of the Mvudi and Nzhelele Rivers. Effluents from Thohoyandou wastewater treatment plant and Siloam waste stabilization ponds were also investigated. Diagnostic ratios were used to evaluate the possible sources of PAHs. PAHs in the water samples were extracted using 1:1 dichloromethane and n-hexane mixtures, while those in the sediment samples were extracted with 1:1 acetone and dichloromethane using an ultrasonication method. The extracts were purified using an SPE technique and reconstituted in n-hexane before analyses with a gas chromatograph time of flight-mass spectrometer. The results obtained indicate the prevalence of high molecular weight PAHs in all the samples. PAHs concentrations in water and sediment samples from all the sampling sites were in the range of 13.174-26.382 mg/L and 27.10-55.93 mg/kg, respectively. Combustion of biomass was identified as the major possible source of PAHs. Effluents from wastewater treatment facilities were also considered as major anthropogenic contributions to the levels of PAHs found in both river water and sediments. Mvudi and Nzhelele Rivers show moderate to high contamination level of PAHs.
authors.affiliation: Department of Hydrology and Water Resources, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa. joshua.edokpayi@univen.ac.za.
authors.forename: Joshua N
authors.initials: JN
authors.lastname: Edokpayi
authors.affiliation: Department of Hydrology and Water Resources, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa. john.odiyo@univen.ac.za.
authors.forename: John O
authors.initials: JO
authors.lastname: Odiyo
authors.affiliation: Department of Chemical Sciences, Yaba College of Technology, P.M.B. 2011 Yaba, Lagos 101212, Nigeria. seunliz27@yahoo.com.
authors.forename: Oluwaseun E
authors.initials: OE
authors.lastname: Popoola
authors.affiliation: College of Science, Engineering and Technology, Nanotechnology and Water Sustainability Research Unit, Florida Science Campus, University of South Africa, 1710 Roodepoort, Johannesburg 2000, South Africa. msagatam@unisa.ac.za.
authors.forename: Titus A M
authors.initials: TA
authors.lastname: Msagati
mesh_terms: D004784:Environmental Monitoring / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry; D019015:Geologic Sediments / Q000032:analysis; D006586:Hexanes; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D045483:Rivers / Q000737:chemistry*; D013019:South Africa; D062065:Wastewater / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D006586:Hexanes; D011084:Polycyclic Aromatic Hydrocarbons; D062065:Wastewater; D014874:Water Pollutants, Chemical; C026385:n-hexane
keywords: contamination; polycyclic aromatic hydrocarbons; river; sediments; wastewater