Evaluation of spatial distribution and health risk of pesticide residues in the environmental matrices of buffalo river estuary and their removal using nanosponges and modified cyclodextrins
- Authors: Mdeni, Nonkululeko Landy
- Date: 2023-03
- Subjects: Chemicals , Hazardous substances , Dangerous chemicals
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27629 , vital:69321
- Description: The contamination of lotic ecosystems caused by agricultural, industrial, and anthropogenic activities has attracted the attention of researchers, authorities, and scientists because these waterbodies are of social and economic importance to human livelihoods. Pesticides and insecticides are a group of compounds that are toxic to pests and insects, respectively. Organophosphate pesticides (OPs) can be released into different environmental matrices through several sources including agricultural and urban runoff. They are one of the three main classes of synthetic organic pesticides that are used in agricultural sector and very often end up in other destinations than their target sites. In this study, four OPs, namely, ronnel, malathion, parathion and Durban were investigated. The Buffalo River Estuary, located in East London, is one of most popular areas and the river is a major source of raw water abstraction for three municipalities in the Eastern Cape Province, South Africa. Sediment samples were collected from six points in the estuary and soil samples were taken from a nearby dumpsite in winter and spring seasons of 2021. The physicochemical parameters of the samples including particle size, moisture content, oil and grease and organic carbon were determined. The samples were then extracted by ultra-sonication, the final extracts were analyzed using GC-μECD and the risk quotient (RQ) method was used to evaluate the risk of OP exposure to aquatic organisms. Polymer modified cyclodextrin (β-CD) for the removal of parathion in sediment and soil was synthesized and the morphology of the modified β-CD and vibrations of the synthesized material were determined using scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy, respectively. The limit of detection (LOD) and the limit of quantification (LOQ) of the OPs investigated were in the range of 0.09 to 2.99 and 0.274 to 9.06 μg/L, respectively. OPs gave a good recovery except for malathion, which had a recovery percentage lower than 70%. Calibration curves were plotted for the four OPs and were linear with relative standard deviations (RSD) ranging from 1.02 to 3.50, and correlation coefficients (R2) ranging from 0.9935 to 0.9972. The mean concentrations for sediments and soil in both seasons varied from 0.00231 to 63.8 μg/g in winter and from 0.0017 to 36.6 μg/g in spring, with malathion being the predominant congener and dursban being the least dominant in both seasons. In winter, the particle size percentages of the sediment and soil samples ranged from 34.4 to 79.4 percentage, 15.4 to 23.9 percentage and from 7.77 to 38.3 percentage for coarse, medium, and fine fractions, respectively. While in spring, the particle size for the course, medium and fine mesh fractions ranged from 37.4 to 74.6 percentage, 14.1 to 25.1 percentage and 12.4 to 35.0 percentage respectively; the percentage moisture content varied from 43.0 to 73.1 in winter, and from 57.1 to 63.4 in spring. In the soil samples, the physicochemical properties were lower in winter except for the n- hexane extractable material (HEM), which significantly decreased in spring from 2.6 to 1.63 mg/kg; while for sediments, the oil and grease ranged from 1.77 to 10.3 mg/kg in winter and from 1.63 to 4.28 mg/kg in spring. The risk quotient method was used to determine the risk of OP exposure to sediment-dwelling organisms and the results obtained indicated that the levels of OPs in this study, especially dursban, can pose a high risk to the organisms in sediments, with RQs higher than ten (˃10) in both winter and summer. The Pearson product-moment correlation showed that parathion had a weak correlation with every other variable except for malathion in winter, whereas in spring, parathion correlated very weakly with malathion; suggesting that products containing parathion are mostly used to control pests found in crops, such as corn and mosquitos, which are most active in the spring season. There was a very strong correlation between dursban and ronnel in spring and winter, implying that an increase in dursban concentration resulted in an increase in the concentration of ronnel. To determine the efficiency of the synthesized adsorbent CD-chitosan-alginate for the removal of Parathion from soil and sediment, different parameters such as concentration, time, pH and dose were varied. The adsorption capacity was found to be highest at pH 2 (99.19 percentage), when 3 mL of the adsorbent was used for 30 minutes. , Thesis (Msci) -- Faculty of Science and Agriculture, 2023
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- Date Issued: 2023-03
Evaluation of functionalized silver and silica nanoparticles for the removal of deoxyribonucleic acid conveying antibiotics resistance genes from water
- Authors: Ezeuko, Adaora Stella
- Date: 2022
- Subjects: DNA , Silica , Water
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27765 , vital:69414
- Description: Antibiotic resistance genes ARGs are recognized as a serious public health emergency linked to extensive use of antibiotics by humans and animals as a prophylactic agent that treats and prevents infections. The occurrence of high concentrations being identified in wastewater treatment plants, rivers, etc is due to untreated effluents being discharged from households, hospitals, agriculture, and pharmaceutical industries. The application of adequate treatment techniques and material for the removal of bacteria DNA conveying ARGs from the effluents before their release to the environment cannot be overemphasized. Adsorption techniques seem to be effective due to their easy design, operation, and ability to regenerate adsorbents for use without producing toxic by-products. This concept was employed for the removal of bacteria DNA conveying ARGs from simulated aqueous solution, effluents from hospital, river and WWTPs using silver and silica metallic nanoparticles. This thesis investigated the effectiveness of metallic nanoparticles containing silver AgNPs and mesoporous silica nanoparticles MSNPs as well as magnetite Fe3O4 functionalized with 4 4hydroxyphenyl 2 262-terpyridine onto their surface, for the removal of bacteria DNA conveying antibiotic resistance genes from water samples from hospitals, river, and wastewater treatment plants WWTPs. Silver nanoparticles AgNPs of different molar concentrations 0.1M, 0.5M and 1.0 M and mesoporous silica nanoparticles MSNPs adsorbents were successfully synthesized in their original states and surface functionalization achieved by incorporating magnetite Fe3O4 and 4 4 hydroxyphenyl 2 2 6 2 terpyridine on the silver AgNPs Fe3O4 and silica MSNPs TPPY surfaces respectively. Their effectiveness as adsorbent for the removal of bacteria DNA conveying ARGs from aqueous solutions and real water/wastewater samples were investigated. The DNA uptake by the as-synthesized AgNPs and MSNPs were compared to the functionalized AgNPs Fe3O4 and MSNPsTPPY by determining the adsorbents with the highest removal efficiencies. All as synthesized and functionalized adsorbents were characterized by SEM, EDX, FTIR, XRD, UV spectroscopy and PZC before the removal process. The extraction of genomic DNA from antibiotic-resistant Enterococcus faecium and Vibrio parahaemolyticus was successfully achieved via the boiling method. Antibiotic susceptibility test was conducted using the disk diffusion method before the commencement of genomic DNA extraction. Molecular characterization via gel electrophoresis confirmed the presence of resistance genes at different base pairs. Adsorption batch experiment were investigated, and the best optimum parameters were evaluated through the influence of pH, contact time, initial DNA concentration, adsorbent dose, and competitive ions for each sorption process. The rate determining step were determined by fitting kinetic models such as Natarajan and Khalaf first order, pseudo first order, pseudo second order, Elovich model to experimental data. Also, the adsorption mechanisms determining adsorption equilibrium were investigated by fitting Freundlich, Langmuir and Sips model into the experimental data. The application of AgNPsFe3O4 nanocomposite and MSNPsTPPY for the removal of bacteria DNA demonstrated much enhancement for DNA uptake than the as-synthesized AgNPs and MSNPs materials. The incorporation of magnetite and 4 4hydroxyphenyl 2 2 6 2-terpyridine onto AgNPs and MSNPs significantly enhanced the binding affinity towards the removal the bacteria DNA via strong electrostatic attraction between the active sites on the adsorbent and the negative DNA molecules. Finally, high adsorption capacities were recorded with AgNPsFe3O4 nanocomposite and MSNPsTPPY compared to AgNPs and MSNPs with chaotropic salts. The kinetic adsorption models were mostly best fitted by the pseudo-second order and Elovich models while the adsorption equilibrium was best described by Langmuir and Sips isotherm models. MSNPs with different chaotropic salts, AgNPsFe3O4 nanocomposite and MSNPsTPPY also proved its effectiveness in DNA removal not only in the simulated aqueous solution but in three different real life water samples obtained from Cofimvaba hospital, Ndevana river and Uitenhage WWTPs. High adsorption efficiencies above 90 percent were achieved during the removal of DNA in all the three real water samples. Therefore, application of these adsorbents for the removal of bacteria DNA conveying ARGs may be a promising option that would tackle the consequences of consuming ARGs infected water globally. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
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- Date Issued: 2022
Isolation and characterization of extracts of Rosmarinus officinalis l. And comparative evaluation of its antimicrobial activity and selected types of antibiotics against some bacteria species
- Authors: Gbede,Remi
- Date: 2019
- Subjects: Rosmarinus Essences and essential oils Lamiaceae Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/19142 , vital:39875
- Description: Rosmarinus officinalis L. is known extensively for its multifunctional purposes. The essential oil has been widely used in cosmeceuticals and several ethnopharmacological values. In vitro studies have demonstrated the antibacterial activity of essential oils (EOs) of Rosmarinus officinalis L. against Staphylococcus aureus ATCC 25923, Vibrio cholerae DSM 19283, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 27853 and Bacillus cereus. These different bacteria were screened against antibiotics such as Tetracycline, Ampicillin Sodium salt, Erythromycin and Amoxicillin, and some standards namely rosmarinic acid, carnosic acid and carnosol, and also against the methanol, acetone, chloroform and dichloromethane extracts of rosemary. The essential oils of Rosmarinus officinalis L. showed significant inhibitory properties compared to antibiotics with various degrees of growth inhibition. The standards exhibited some activities against the organisms. The GC/MS analysis of the essential oil revealed 34 compounds present with most components acting in synergy to bring about antibacterial activities. The antiplasmodial and cytotoxic activities of two leaf extracts of Rosmarinus officinalis (with hexane and dichloromethane as solvents) using standard procedure were studied. The findings justify the claims on the efficacy of plants for therapeutic uses for antifungal, antibacterial and anti-inflammatory properties. Antiplasmodial activity of Rosmarinus officinalis recorded IC50 values of 9.99 µg/ml and 9.76 µg/ml in hexane and dichloromethane respectively.
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- Date Issued: 2019
Evaluation of the physicochemical qualities and heavy metal regimes of the final effluents of some wastewater treatment facilties in Berlin, Alice and Bedford communities in the Eastern Cape, South Africa
- Authors: Agoro, Mojeed Adedoyin
- Date: 2017
- Subjects: Water -- Purification -- South Africa -- Eastern Cape Sewage -- Purification -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5003 , vital:28924
- Description: Wastewater treatment facilities have been identified as potential source of surface water pollution worldwide. In this study, the physicochemical qualities and heavy metal (including Zinc, Cadmium, Iron, Lead and Copper) concentrations in the final effluents, as well as the reduction efficiencies of three municipal wastewater plants in the Eastern Cape, South Africa were evaluated from September 2015 to February 2016 using standard methods. Wastewater effluent and sludge samples were collected from the selected plants on monthly basis over a period of six months from September 2015 to February 2016. Standard analytical method (Atomic absorption spectroscopy [AAS]) was used to assess the concentration levels of heavy metals. The physicochemical parameters assessed include pH, Temperature, Total Dissolved Solid, Turbidity, Biochemical Oxygen Demand, Chemical Oxygen Demand, Alkalinity, Dissolved Oxygen, Free chlorine, Chloride, Sulphate, Phosphate, Ammonium and Electrical Conductivity. The results of the evaluation showed that temperature ranges from 19 to 36 °C, Electrical Conductivity from 60-1095 mS/m, Alkalinity from 2.6-20.9 mg/L, Nitrate from 0.24-26.5 mg/L, Nitrite from 0.01-90 mg/L, Phosphate from 0.02-5.12 mg/L, Ammonium from 0.06-112 mg/L, Sulphate from 3-72 mg/L, Chloride from 3.25-224 mg/L, Chemical Oxygen Demand from 17-394 mg/L and Turbidity from 1.96-715 NTU. Free chlorine concentrations and dissolved oxygen were within the recommended limits for most part of the sampling period and ranged between 0.17-0.48 mg/L and 0.19-21.9 mg/L respectively. The pH, Phosphate, Sulphate and Free chlorine were within acceptable limits while Electrical Conductivity, Temperature, Total Dissolved Solid, Turbidity, Chemical Oxygen Demand, Chloride, Ammonium, Nitrate and Nitrite were not within specified limits. The reduction efficiencies observed generally ranged between 43.9 and 100 percent at all sampling points while zinc and lead were not detected throughout the sampling period. Cadmium showed low reduction rate ranging from 0 to 11.7 percent, while the rate of Copper reduction ranged from 0 to25 percent in January and February 2016. Zinc, lead and cadmium were generally not detected in the sludge samples except in January and February which could be due to the prevailing atmospheric conditions during the sampling period. Cu and Fe were detected through the sampling months of the study. We conclude that these municipal sewage plants are sources of pollution to their receiving watersheds and threats to public and environmental health.
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- Date Issued: 2017
Physiochemical and heavy metals fingerprints of the final effluents of Adelaide and Seymour wastewater treatment facilities in the Eastern Cape, South Africa
- Authors: Mutukwa, Dorcas
- Date: 2017
- Subjects: Water -- Purification Effluent quality -- Testing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8089 , vital:31520
- Description: Wastewater contains pathogens, heavy metals, nutrients, organic matter and other toxic chemicals and when discharged into the environment without proper treatment, it may cause adverse health problems and environment degradation. There have been reports in the Eastern Cape Province, South Africa of inadequate treated wastewater effluents being discharged into freshwater environments. This study reports on the physicochemical and heavy metals qualities for two wastewater treatment facilities in the Eastern Cape, South Africa over a six-month sampling period (September 2015 to February 2016). Wastewater effluent samples were collected from the influents, final effluents and receiving waterbodies as well as sludge samples in replicates. The physicochemical parameters were analysed using standard methods (APHA, 2012). The acid digested heavy metals samples were analysed using Atomic Absorption Spectrophotometer (iCE 3500 Thermo Fisher Spectrometer). The concentrations were compared to recommended limits used in South Africa and World Health Organisation (WHO). Physicochemical qualities assessed at Adelaide wastewater treatment plant ranged as follows: temperature (21.6 - 30.5 oC), turbidity (2.1 – 71.3 NTU), electrical conductivity (EC) (743.0 – 898.3 μ/Scm) and dissolved oxygen (DO) (2.11 – 3.50 mg/L) while the ranges of the parameter assessed at Seymour wastewater treatment plant ranged as follows: chemical dissolved oxygen (COD) (41.7 – 115.3 mg/L), EC (628 and 797.7 μ/Scm) and nitrates (4.6 – 11.0 mg/L. The heavy metals concentration for the final effluents at Adelaide wastewater treatment plant ranged as follows: Cd (0 – 0.002 mg/L), Cu (0 – 0.096 mg/L) and Fe (0 – 0.498 mg/L). Cu concentrations in sludge at Seymour wastewater treatment plant ranged between 83.82 and 132.07 mg/L. Reduction efficiencies of Adelaide in removing chlorides and sulphates were 33 and 36 percent respectively. Findings of study revealed negative impacts of inadequately treated effluents on receiving waterbodies and this puts communities which rely on the water as immediate source of fresh water for domestic purposes at health risk.
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- Date Issued: 2017
Spatial and seasonal distribution of selected persistent organic pollutants and phenolic derivatives along the course of the Buffalo River in the Eastern Cape Province of South Africa
- Authors: Yahaya, Abdulrazaq
- Date: 2017
- Subjects: Organic water pollutants Water -- Purification -- Organic compounds removal
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5939 , vital:29448
- Description:
Persistent organic pollutants (POPs) fall under a group of synthetic chemicals known for their persistence in environmental matrices such as soil and water, and are used in industrial, domestic and agricultural applications. Because of their volatility and lipophilicity, POPs can be transported far away from their point sources and bio-accumulate in food and in fatty tissues of humans and animals. In view of their toxicity and carcinogenicity some organic pollutants such as polychlorinated biphenyl (PCBs), organochlorine pesticides (OCPs) and phenolic derivatives (chlorophenol and nitrophenol) have been classified by United State Environmental Protection Agency (USEPA) and World Health Organization (WHO) as priority pollutants. The present work evaluated the distribution patterns of 19 polychlorinated biphenyls congeners, 17 organochlorine pesticides and selected phenolic derivatives (USEPA 11-priority pollutants) in the Buffalo River, in the Eastern Cape Province, South Africa between December 2015 and May 2016. The Liquid-liquid extraction technique was used for PCBs, OCPs and phenolic derivatives in the river water samples. Silica gel and florisil clean up were carried out for PCBs and OCPs samples respectively and analyzed with gas chromatography electron capture detector (GC/ECD). Phenolic compounds were derivatized and analyzed by gas chromatography mass spectrometer (GC/MS). Limits of detection (LOD), limit of quantitation (LOQ) and relative standard deviation (RSD) for the PCBs were 10 to 330 ng/L, 20 to 1,060 ng/L and 1.18 to 14.1 percent respectively. The LOD, LOQ and RSD for the OCPs were from 20 - 60 ng/L, 110 - 530 ng/L and 0.02 - 0.06 percent, while the corresponding values for the phenolic derivatives were 10 to 70 ng/L, 33 to 222 ng/L and 1.99 - 10.86 percent. In summer, the concentrations of PCBs, OCPs and phenolic derivatives ranged from
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- Date Issued: 2017