http://hdl.handle.net/11189/5117 2026-09-04T10:20:54Z 2026-09-04T10:20:54Z Daso, Adegbenro P Fatoki, Olalekan S Odendaal, James P Olujimi, O.O. http://hdl.handle.net/11189/4744 2020-11-05T12:14:59Z 2011-01-01T00:00:00Z

Title: Assessment of selected polybrominated diphenyl ethers and 2,2’, 4,4’, 5,5’- hexabromobiphenyl (BB-153) in bottom sediments of the Kuils River, Cape Town Authors: Daso, Adegbenro P; Fatoki, Olalekan S; Odendaal, James P; Olujimi, O.O. Abstract: An assessment of the concentrations of selected polybrominated diphenyl ether (PBDE) congeners as well as BB 153 in leachate samples collected from three landfill sites within the city of Cape Town was conducted. A liquid–liquid extraction technique was employed for the isolation of all the target compounds from the leachate samples. Extracts obtained were further subjected to multi-layer column chromatography employing different forms of silica gel. The prepared samples were analysed using a high capillary gas chromatograph equipped with a micro-electron capture detector (GC-μECD). The overall mean concentrations of the total PBDEs, including BDE 209 ranged between 5.65 and 2,240, 0.28–20.5 and 1.66–1,170 ng/l for Bellville, Coastal Park, and Vissershok landfill sites, respectively. The mean concentrations of BB 153, which were generally low in most of the samples analysed, were 70.4, 7.14 and 8.16 ng/l for Bellville, Coastal Park and Vissershok sites, respectively. The influence of precipitation on the characteristics and quantity of leachate produced from the landfill sites investigated was most pronounced during the August/September sampling regime.

2011-01-01T00:00:00Z Daso, Adegbenro P Fatoki, Olalekan S Odendaal, James P http://hdl.handle.net/11189/4739 2020-11-05T12:15:28Z 2011-01-01T00:00:00Z

Title: Development of analytical procedures for the simultaneous determination of tri- to heptabrominated diphenyl ethers and hexabrominated biphenyl (BB 153) in sediment samples Authors: Daso, Adegbenro P; Fatoki, Olalekan S; Odendaal, James P Abstract: A simple analytical procedure was developed for simultaneous determination of trace levels of tri- to hepta-BDEs as well as 2,2′,4,4′,5,5′-hexabromobiphenyl (BB 153). The mechanical shaking extraction technique for the isolation of target analytes was optimised. Different extraction solvent combinations were tested under different extraction time periods of 3, 6, 12 and 16 h. The n-hexane:acetone (2:1, v/v) combination gave the best recovery at the optimum extraction of 12 h. Target analytes were quantified using a high capillary gas chromatograph (GC) equipped with an electron capture detector. Under the optimum GC conditions, the resolution of the co-eluting BDE 154 and BB 153 was achieved. The overall recoveries of target analytes in the matrix spike experiment conducted ranged between 84.4 and 110% for BDE 183 and BDE 28, respectively. The method was applied to 19 field sediment samples collected from a control site and from 3 sampling locations (upstream, point of discharge and downstream) of the Black River, which receives effluent from a wastewater treatment plant (WWTP). The sum of the mean concentrations of all of the 7 PBDE congeners was 4.63, 0.35, 'not detectable' and 4.43 ng/g, for the control site, upstream, point of discharge and downstream samples, respectively. The concentrations of BB 153 were generally low in these samples and ranged between ND and 0.89 ng/g. The developed method allows for the simultaneous determination of PBDE congeners and BB 153. It is efficient, moderately rapid and cost-effective.

2011-01-01T00:00:00Z Olujimi, O.O. Fatoki, Olalekan S Odendaal, James P Okonkwo, OJ http://hdl.handle.net/11189/4698 2020-06-04T11:03:50Z 2011-01-01T00:00:00Z

Title: Solid-phase extraction method for the analysis of eleven phenolic pollutants in water samples Authors: Olujimi, O.O.; Fatoki, Olalekan S; Odendaal, James P; Okonkwo, OJ Abstract: An analytical protocol for the determination of priority phenolic compounds: phenol, 2-methyl 4,6-dinitrophenol, 2-chlorophenol, 2,4- dichlorophenol, 2,4,6-trichlorophenol, pentachloro-phenol, 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 4-chloro-3-methylphenol, 2,4,6-tribromophenol and 2,4-dimethylphenol, in water samples using strata C18 cartridge is presented. Different parameters affecting extraction and peak separation were optimized. Recoveries using spiking of the test compounds varied in the ranged between 69.43 ± 1.76 % and 101.87 ± 0.45 %. The high recoveries obtained validated the method. Detection limits obtained ranged from 4 µg L-1 for 2,4- dimethylphenol to 166 µg L-1 for 4-nitrophenol, using LC-UV. The results obtained by applying the developed method to real environmental water sample containing 2,4-dichlorophenol, 2-methyl, 4,6-dinitrophenol, pentachlorophenol and 2,4,6-tribromophenol indicated the following concentration levels: 5.129, 0.561, 4.788 and 0.868 ng µL-1 , respectively.

2011-01-01T00:00:00Z Olujimi, O.O. Fatoki, Olalekan S Odendaal, James P http://hdl.handle.net/11189/4697 2020-06-04T11:03:25Z 2011-01-01T00:00:00Z

Title: Method development for simultaneous determination of phthalate and eleven priority phenols as tert-butyldimethylsilyl derivatives in grab samples from wastewater treatment plants using GC-MS in Cape Town, South Africa Authors: Olujimi, O.O.; Fatoki, Olalekan S; Odendaal, James P Abstract: Method was developed for the simultaneous determination of 17 classified and suspected endocrine-disrupting compounds (EDCs). Phenol, 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 4-chlorophenol, 2,4-dimethylphenol, 2- methyl 4,6-dinitro-phenol, 2-chlorophenol, 2,4-dichlorophenol, 4-chloro-3-methylphenol, pentachlorophenol, dimethyl phthalate, diethyl phthalate, benzylbutyl phthalate, dioctyl phthalate, diethylhexylphthalate and dibutyl phthalate. Qualitative and quantitative analyses were performed by gas chromatography–mass spectrometry (GC–MS) using DB-5MS column. These compounds were evaluated using solid-phase extraction for raw and treated wastewater from a municipal treatment plant. Phenols were derivatized with N-(t-butyldimethylsilyl)-N-methyl-trifluoroacetamide (MTBSTFA) to form their respective t-butyldimethylsilyl derivatives. The extraction recovery range from 73.21 to 101.32% for 2,4,6-TCP and DEHP respectively. The occurrence pattern of phenol is in the order of PCP > 2CP > POH > 2NP > 2M- 4,6 DNP (old plant) and PCP > 2M- 4,6 DNP > POH ≥ 2CP ≥ 2NP for old and new plants respectively. Phthalates ranked as DEP > DBP > DEHP with corresponding values of 2473 ± 991; 2000 ± 236; and 192 ± 127 µgL-1 in the new plant. The average percent removal of analytes range from 54.77 to 89.34% in the two plants investigated.

2011-01-01T00:00:00Z