Browsing by Author "Moodley, Brenda"

Now showing 1 - 11 of 11
  • Thumbnail Image
    Item
    Assessment of nonsteroidal anti-inflammatory drugs by ultrasonic-assisted extraction and GC-MS in Mgeni and Msunduzi river sediments, KwaZulu-Natal, South Africa
    (Environmental Science and Pollution Research, 2017) Gumbi, Bhekumuzi P.; Moodley, Brenda; Birungi, Grace; Ndungu, Patrick G.
    The occurrence of eight pharmaceuticals was monitored during four seasons (spring, summer, autumn, and winter) along a 250-km stretch of the Msunduzi and Mgeni rivers in KwaZulu-Natal, South Africa. This paper describes an optimized method for the determination of nonsteroidal antiinflammatory drugs (NSAIDs) in sediments. The method combines ultrasonic, centrifuge, and gas chromatographymass spectrometry for the detection of these drugs in solid samples. Most of the parameters that affect the extraction step were optimized. Solid samples were placed in a centrifuge tube and extracted with ethyl acetate:acetone (1:1, two cycles), followed by clean-up with Oasis HLB cartridge and derivatization with N, O-bis(trimethylsilyl) trifluoroacetamide (BSTFA). Satisfactory recoveries were obtained ranging from 66 to 130%, depending on the analyte. Precision expressed as RSD (%) (n = 3) was less than 20%for all analytes. The LODs and LOQs were in the range of 0.024 to 1.90 ng g−1 which allowed to be applied in the analysis solid samples in Msunduzi and Mgeni rivers. In the solid samples analyzed, NSAID concentration ranged from not detected to 221 ng g−1.
  • Thumbnail Image
    Item
    Detection and quantification of acidic drug residues in South African surface water using gas chromatography-mass spectrometry
    (Chemosphere, 2017) Gumbi, Bhekumuzi P.; Moodley, Brenda; Birungi, Grace; Ndungu, Patrick G.
    A method was optimized for derivatization, separation, detection and quantification of salicylic acid, acetylsalicylic acid, nalidixic acid, ibuprofen, phenacetin, naproxen, ketoprofen, meclofenamic acid and diclofenac in surface water using gas chromatography-mass spectrometry. For most of the acidic drugs, recovery was in the range 60e110% and the percent standard deviation was below 15% for the entire method, with limits of detection ranging from 0.041 to 1.614 mg L-1. The developed method was applied in the analysis of acidic drugs in Umgeni River system, KwaZulu-Natal South Africa. All of the selected acidic drugs were detected and quantified, their concentration in Umgeni River system ranged from 0.0200 to 68.14 mg L-1.
  • Thumbnail Image
    Item
    Evaluation of organochlorinated pesticide (OCP) residues in soil, sediment and water from the Msunduzi River in South Africa
    (Environmental earth sciences, 2019) Adeyinka, Gbadebo Clement; Moodley, Brenda; Birungi, Grace; Ndungu, Patrick
    Organochlorinated pesticide (OCP) concentrations were evaluated in sediment, soil and surface water of the Msunduzi River as well as the influent, effluent and biosolids from the Darvill wastewater treatment plant (WWTP) of Pietermaritzburg, South Africa. Samples were extracted with dichloromethane using an ultra-sonication method, and cleaned up using multilayered silica gel and analysed using gas chromatography-mass spectrometry. The results showed that all 13 selected OCPs were detected in all the environmental media as well as in the wastewater treatment plant samples. The results revealed that the OCP concentrations along the sites varied based on the anthropogenic activities of the area. The influent of the Darvill WWTP and Du Toit (DUT) site were found to be the most polluted sites. The results from the winter sampling showed highest concentrations of OCPs compared to the spring season. Sediment was found to contain significant amounts of all the selected OCPs with water samples containing the lowest concentrations for both winter and spring seasons. Among the OCPs evaluated, dichlorodiphenyltrichloroethane (DDT) and its metabolites were predominant in all.
  • Thumbnail Image
    Item
    Evaluation of persistent organochlorine pesticides and polychlorinated biphenyls in Umgeni River bank soil, KwaZulu- Natal, South Africa
    (Water SA, 2019) Gakuba, Emmanuel; Moodley, Brenda; Ndungu, Patrick; Birungi, Grace
    is study investigated the presence and distribution of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in soil collected along the banks of the Umgeni River, one of the largest rivers in the province of KwaZulu-Natal, South Africa. e analysis was performed using gas chromatography-mass spectrometry (GC-MS). e results showed that the levels of OCPs ranged from 3.58±0.09 ng/g for hexachlorobenzene (HCB) to 82.65±2.82 ng/g for HCH, with an individual mean concentration of 24.33±2.00 ng/g dry weight (dw). e levels of PCBs ranged from 10.46 ng/g for PCB105 to 89.46 ng/g for PCB180, with an average PCB value of 25.47±1.26 ng/g, dw. e highest levels of OCPs and PCBs were found at Northern Wastewater Treatment Plant (mean OCP: 32.39±3.97 ng/g and PCB: 67.87±1.67 ng/g). e two most abundant contaminants in the river were endrin and PCB180.
  • Thumbnail Image
    Item
    Occurrence and significance of polychlorinated biphenyls in water, sediment pore water and surface sediments of Umgeni River, KwaZulu-Natal, South Africa
    (Environmental monitoring and assessment, 2015) Gakuba, Emmanuel; Moodley, Brenda; Ndungu, Patrick; Birungi, Grace
    The Umgeni River is one of the main sources of water in KwaZulu-Natal, South Africa; however; there is currently a lack of information on the presence and distribution of polychlorinated biphenyls (PCBs) in its sediment, sediment pore water and surface water. This study aims to determine the occurrence and significance of selected PCBs in the surface water, sediment pore water and surface sediment samples from the Umgeni River. Liquid-liquid and soxhlet extractions were used for water or pore water, and sediments, respectively. Extracts were cleaned up using a florisil column and analysed by gas chromatography-mass spectrometry. The total concentrations of eight polychlorinated biphenyls were 6.91–21.69 ng/mL, 40.67–252.30 ng/mL and 102.60–427.80 ng/g (dry weight), in unfiltered surface water, unfiltered sediment pore water and surface sediments, respectively. The percentage contributions of various matrices were 4, 36 and 60% for unfiltered surface water, unfiltered pore water and sediment, respectively. The highest concentrations of PCBs were found in water, pore water and sediment collected from sampling sites close to the Northern Wastewater Treatment Works. The highest chlorinated biphenyl, PCB 180, was the most abundant at almost all sampling sites. To our knowledge, this is the first report on occurrence of polychlorinated biphenyls in the Umgeni River water, pore water and sediment system and our results provide valuable information regarding the partitioning of the PCBs between the water and sediment systems as well as the organic chemical quality of the water.
  • Thumbnail Image
    Item
    Occurrence of selected pharmaceuticals in water and sediment of Umgeni River, KwaZulu-Natal, South Africa
    (Environmental Science and Pollution Research, 2015) Matongo, Solomon; Birungi, Grace; Moodley, Brenda; Ndungu, Patrick
    Selected pharmaceuticals including antibiotics, antipyretics, a stimulant, an antiepileptic and an antipsychotic drug were determined in wastewater, surface water and sediment along the Umgeni River which is the main source of water to Durban City in KwaZulu-Natal, South Africa. Samples were analysed using high-performance liquid chromatography coupled to a mass spectrometer (HPLC-MS/MS) after clean up and pre-concentration by solid phase extraction (SPE). At the wastewater treatment plant outlet, the antipyretic ibuprofen was detected in concentrations up to 12.94 μg/L and 15.96 ng/g in wastewater and bio-solids, respectively. The antipsychotic clozapine was detected in concentrations up to 14.43 μg/L and 18.75 ng/g in wastewater and bio-solids, respectively. Other pharmaceuticals namely sulfamethazine, sulfamethoxazole, erythromycin, metronidazole, trimethoprim, acetaminophen, caffeine and carbamazepine were also detected but in lower concentration compared to clozapine and ibuprofen (<10 μg/L or 10 ng/g). Clozapine and ibuprofen were detected at high concentrations in the surface water and sediment of Umgeni River. The highest concentration of clozapine (78.33 μg/L) was detected at the business park, while that for ibuprofen (62.0 μg/L) was detected at the point where a tributary, Msunduzi, joins Umgeni. Metronidazole was only detected in sediment, and caffeine (2243.52 ng/g) was detected at the highest concentration in the sediment at the blue lagoon sampling site. The antibiotic sulfamethoxazole was also detected in appreciable amounts up to 507.34 ng/g in the sediment at the Msunduzi tributary sampling site. The data collected implies that while insufficiently treated wastewater contributes to surface water contamination, human activities also contribute appreciably to the pharmaceutical loading of River Umgeni.
  • Thumbnail Image
    Item
    Pharmaceutical residues in water and sediment of Msunduzi River, KwaZulu-Natal, South Africa
    (Chemosphere, 2015) Matongo, Solomon; Birungi, Grace; Moodley, Brenda; Ndungu, Patrick
    The little data about pharmaceutical residue contamination in African water bodies motivated our study on the occurrence of pharmaceutical residues in the water and sediment of Msunduzi River in the KwaZulu-Natal province of South Africa; and in the Darvill wastewater treatment plant found in Msunduzi catchment. Samples collected along the River and wastewater treatment plant were extracted and analysed for pharmaceutical residues selected based on statistics of drug usage in South Africa i.e. antipyretics, antibiotics, caffeine, an antiepileptic and an antipsychotic drug were determined using HPLC–MS/MS. In all the matrices investigated, the antipyretic ibuprofen had the highest concentration of up to 117 lg L 1, 84.60 lg L 1 and 659 ng g 1 in wastewater, surface water and sediment respectively. Antibiotics were detected in generally low concentrations of <10 lg L 1 in surface water samples and up to 34.50 lg L 1 in wastewater; moreover they were not completely removed during wastewater treatment. The percentage removal efficiency of the studied group was 6.55–98.00% for antipyretics, 73.33– 98.90% for antibiotics, 48.80% for the anti-epileptic drug and 86.40% for Caffeine. Clozapine exhibited a negative removal. In surface water, Henley dam exhibited a high concentration of the pharmaceutical residues and the highest concentration of metronidazole in sediment (up to 1253.50 ng g 1) detected. Metronidazole was only detected in sediment and bio-solids.
  • Thumbnail Image
    Item
    Quantitative analyses of selected polychlorinated biphenyl (PCB) congeners in water, soil, and sediment during winter and spring seasons from Msunduzi River, South Africa
    (Environmental monitoring and assessment, 2018) Adeyinka, Gbadebo Clement; Moodley, Brenda; Birungi, Grace; Ndungu, Patrick
    The lack of information and the need for knowledge on the organic pollutants within the area of KwaZulu-Natal together with the global problem of water supply have prompted our investigation into the analyses of eight polychlorinated biphenyl (PCB) congeners in the Msunduzi River of KwaZulu-Natal, South Africa. Soil, sediment, and water sampleswere collected at ten different sites along the river during winter and spring seasons. Soil and sediment samples were extracted using ultra sonication with dichloromethane while water samples were liquid-liquid extracted using dichloromethane. All sample extracts were cleaned-up using a multi-layer silica gel column and analyzed with gas chromatography-mass spectrometry. Quality assurance measures were also determined. The percentage recoveries for water were 53–128 for all the PCBs analyzed, while sediment recoveries ranged between 69 and 105%. The highest total concentrations of the PCBs in sediment were 214.21–610.45 ng/g dw at the Du Toit sampling site and 30.86–444.43 ng/g dw basis at the wastewater treatment inlet for winter and spring, respectively. Soil PCB concentrationswere 76.53–397.75 ng/g dw at the Msunduzi Town sampling site and 20.84– 443.49 ng/g (dry weight) at the Du Toit sampling site for winter and spring, respectively. In addition, high PCB concentrations were found in effluent of the wastewater treatment inlet compared to other sampling sites, which ranged between 0.68–22.37 and 2.53–35.69 ng/ mL for winter and spring seasons, respectively. In all the sampling sites selected for this study, Du Toit afforded the highest PCB concentration levels and the lowest was after chlorination at the Darvill wastewater treatment plant. The results presented are new and it is the first study of organic pollutants such as PCBs that has been carried out on this river.
  • Thumbnail Image
    Item
    Spectrophotometric Determination of Low Levels of the Orthophosphate Anion as Molybdenum Blue using Sodium Thiosulphate Reducing agent
    (Oriental Journal of Chemistry, 2020) Nalumansi, Irene; Birungi, Grace; Moodley, Brenda; Tebandeke, Emmanuel
    A simple spectrophotometric method for the determination of low levels of the orthophosphate (PO4 3-) in environmental water systems is reported. The method is based the formation of the phosphomolybdate from the condensation of molybdate and orthophosphate in aqueous acid medium followed by reduction with sodium thiosulphate to form phosphomolybdenum blue. The system obeys Beer’s law at 880 nm (λmax) in the 0.005–0.06 mg P mL-1 phosphate concentration range. Molar absorptivity, Sandell’s sensitivity and correlation coefficient values for the determination were 57526 L mol-1 cm-1, 0.2835 μg cm-2 and 0.9948 respectively. The limit of detection was 2.213 x 10-3 mg P mL-1. The results of PO4 3- determination in water samples obtained using the spectrophotometric method developed in this study, compare favourably with those generated using the Murphy and Riley method which is commonly used for this analysis. Therefore, the study ably demonstrates the suitability of the present spectrophotometric method for analysis of the orthophosphate in environmental water samples.
  • Thumbnail Image
    Item
    Synthesis and characterization of hematite biocomposite using cassava starch template for aqueous phase removal of fluoride
    (Carbohydrate Polymer Technologies and Applications, 2022) Ojok, Walter; Ntambi, Emmanuel; Bolender, James; Wasswa, John; Wanasolo, William; Moodley, Brenda
    In this study, facile synthesis of α-Fe2O3 biocomposite was mediated by cassava starch as a soft template. Batch mode evaluated its sorption behavior for fluoride removal from aqueous media. Characterization studies using analytical techniques confirmed the existence of porous α- Fe2O3 biocomposite with heterogeneous surfaces having a varied affinity for fluoride. The sorption process was optimized using central composite design (CCD) in response surface methodology (RSM) with a good model prediction (R2 = 0.9066). A study of the interaction effect showed the synergy of process variables on fluoride removal with the result’s intensity indicated by the nature of contour plot curvature. Based on the RSM optimization, an optimum fluoride removal efficiency of 85.26 % can be achieved at an initial fluoride concentration of 55 mg/L, α- Fe2O3 biocomposite dose of 0.55 g, pH of 7.5, and contact time of 95 min. Sorption equilibrium data were well modeled by Freundlich isotherm (0.9916), indicating multilayer sorption on a heterogeneous surface of the sorbent with a varied affinity for fluoride. Presence of co-existing anions reduced fluoride removal efficiency in the order PO43􀀀 > HCO3􀀀 > SO4 2 􀀀 > NO3􀀀 > CƖ􀀀 . At the same time, its kinetics was better modeled by pseudo-second-order kinetics (R2 = 0.9764), showing that the sorption process is rate-limiting. The sorption thermodynamics study showed that the process was spontaneous, exothermic, and entropy-driven physisorption. Hence, the results signify that the green synthesized α- Fe2O3 biocomposite could be a potential sorbent for sustainable defluoridation.
  • Thumbnail Image
    Item
    Target, Suspect and Non-Target Screening of Silylated Derivatives of Polar Compounds Based on Single Ion Monitoring GC-MS
    (International journal of environmental research and public health, 2019) Bhekumuzi, Prince Gumbi; Moodley, Brenda; Birungi, Grace; Gathura Ndungu, Patrick
    There is growing interest in determining the unidentified peaks within a sample spectra besides the analytes of interest. Availability of reference standards and hyphenated instruments has been a key and limiting factor in the rapid determination of emerging pollutants in the environment. In this work, polar compounds were silylated and analyzed with gas chromatography mass spectrometry (GC-MS) to determine the abundant fragments within the single ion monitoring (SIM) mode and methodology. Detection limits and recoveries of the compounds were established in river water, wastewater, biosolid and sediment matrices. Then, specific types of polar compounds that are classified as emerging contaminants, pharmaceuticals and personal care products, in the environment were targeted in the Mgeni and Msunduzi Rivers. We also performed suspect and non-target analysis screening to identify several other polar compounds in these rivers. A total of 12 compounds were quantified out of approximately 50 detected emerging contaminants in the Mgeni and Msunduzi Rivers. This study is significant for Africa, where the studies of emerging contaminants are limited and not usually prioritized.