Babajide Alo - Academia.edu (original) (raw)
Papers by Babajide Alo
Nigerian Journal of Environmental Sciences and Technology, Oct 1, 2020
Lagos is the largest producer of municipal solid waste in Nigeria, yet it is the smallest of Nige... more Lagos is the largest producer of municipal solid waste in Nigeria, yet it is the smallest of Nigeria's 36 states with the highest projected population, highest level of urbanization and it houses Nigeria's largest chief port, and principal economic and cultural centres. Out of the total waste generated, only about 73 percent actually got to the final disposal site. There is a possibility of inefficient and ineffective municipal solid waste management system in place which can damage the ecosystem services, contaminate ground and surface water, creates greenhouse gas emissions, increase disease transmission, damages ecosystem services and discourages tourism and other businesses. To this end, this study analysed the efficiency and effectiveness of solid waste services and; the efficiency and effectiveness of solid waste services in Lagos State using primary data and conducting statistical tests. The study found a general agreement on what constitutes efficient and effective solid waste services. However, the study concluded that the waste management system in Lagos State is inefficient, ineffective and therefore; unsustainable. The study therefore recommends among others the urgent need to reorganize the waste management institutions for effective and efficient performance. This requires substantial planning ability, appropriate equipment and continuous managerial optimization of vehicles and workers productivity, efficient vehicle routing, better designed vehicles, managerial incentives, faster vehicle repairs, vehicle standardization.
INTRODUCTION: Effective utility of mixed waste in the landfills lies before its complete degradat... more INTRODUCTION: Effective utility of mixed waste in the landfills lies before its complete degradation rather than after landfill closure. The elemental and chemical constituents of an active and a closed landfill composite were compared using Fourier transform - infrared (FTIR) spectroscopy, scanning electron microscope / energy-dispersive X-ray (SEM/EDX) spectroscopy, and proximate analysis in order to determine potential alternative uses. METHOD: Landfill sites were systematically gridded into seven cells according to RCRA USEPA guidelines. Three samples were obtained from each cell at upper (0-15cm), mid (16-35cm) and low- (36-50cm) depths, both during the dry and wet seasons. The dried samples were separated by size into composites of less degraded (S> 0.63mm) and more degraded (S<0.63mm) components and homogenised. Proximate parameters (ash, volatile and fixed carbon) of samples were determined by ASTM D3174-5 methods. An Alpha attenuated total reflectance -FTIR spectrometer (Bruker) and X-Max SEM/EDX Instruments were used to evaluate the functional and elemental properties. RESULTS: both landfills had similar major elemental constituents representing 96.5% and 98.4% of elemental composition for the closed (O > C > Si> Fe > Ca >Al) and active(C > O > Si > Al > Ca > Fe) landfill samples. Cluster analysis revealed that elemental similarities were more influenced by the level of composite degradation (more degraded / less degraded) than by depth or seasonal variations. FTIR absorption peaks of both landfill samples indicated mineralised waste constituent with some distinguishing peaks peculiar to each landfill. The average ash content (>51%) of the waste in both landfills was above the level considered suitable for energy recovery from waste. DISCUSSION: The absence of major organic peaks precludes use of the waste for soil enrichment and anaerobic digestion feeds, but not for landfill covering. These findings, from rapid and amenable spectroscopic techniques, inform strategic management decisions for landfills
Microwave acid digestion of solid samples combined with inductively coupled plasma – mass spectro... more Microwave acid digestion of solid samples combined with inductively coupled plasma – mass spectrometry (ICP-MS) provides a viable approach to quantification of heavy metals within landfill waste. The efficiency of Aqua regia and HNO3 in microwave digestion of both closed and active landfill composites was compared, with a view to relating heavy metals distribution to the particle size of the landfill composites. Landfill sites were systematically gridded into seven cells according to RCRA USEPA guidelines. Three samples were obtained from each cell at upper (0-15cm), mid (16-35cm) and low- (36-50cm) depths. The particle size was determined using the sieving method and grouped as less degraded (S> 0.63mm) and more degraded (S<0.63mm) components and homogenised. Microwave digestion of samples was carried according to the EPA3052 method using a CEM MARS Xpress digester. An Agilent 7500 ICP-MS was used to determined metal concentrations in digested samples. For 77% of the eleven USEPA toxic heavy metals investigated, microwave digestion with Aqua regia resulted in higher concentration of metals than with HNO3. Extraction precision for both acids was within acceptable limit for more degraded samples (RPD10%) a higher burden of heavy metals in closed landfill samples than active landfill samples, except for Ag and Zn. The more degraded component of both landfills had elevated concentrations of heavy metals (>4% for HNO3 and >6% for Aqua regia). Sample recoveries based on CRM analysis showed that both acids were within the same accuracy (between 88% and 95%
Waste Management & Research, Jul 30, 2018
Landfills' heterogeneous composites waste were evaluated as precursors for generation of activate... more Landfills' heterogeneous composites waste were evaluated as precursors for generation of activated carbon (AC). A single step chemical activation process was applied involving irradiation with microwave energy and impregnation with KOH. The average percentage yield of AC from active landfill precursor was higher than that from closed landfill for all depths sampled. Increase in impregnation ratio and irradiation power decreased the average percentage yield for both landfill precursors (Active: 38.1 to 33.1%) (Closed 42.1: to 33.3%). The optimum pH range for adsorption of methylene blue was pH 6-7, while adsorption increased with increase in temperature over the range 30 to 50 o C. Carbonyl and hydroxyl groups were the major functional groups on the surface of AC. The properties of the AC are potentially suitable for the removal of cationic dyes and pollutants. AC generated from the landfill composite were comparable to that from some other biomass being managed through AC generation. This is the first report to demonstrate the possible reuse of landfill composite as AC. The reuse option of landfill composite could provide a means of sustainable management of landfilled municipal waste.
Waste Management, Aug 1, 2018
Multivariate analysis of a heavy metal pollution survey of closed and active landfill precursors ... more Multivariate analysis of a heavy metal pollution survey of closed and active landfill precursors was carried out in order to compare environmental risk levels in relation to age, particle size and depth of the precursors. Landfill precursors (77) were collected and analyzed for 15 USEPA toxic heavy metals using ICP-MS. Heavy metals concentrations in closed landfill precursors were significantly higher than those in the active landfill for 11 of 15 heavy metals investigated (closed landfill order: Fe > Al > Mn > Cu > Pb > Ba> Co > Cr > Ni > Cd 15 > As > Se > Ti). Cluster analysis and correlation studies indicated the distribution of the metals was more influenced by landfill precursor size than by depth of the sample. Principal component analysis (PCA) showed that 10 of 15 of heavy metals of both landfill precursors were from similar anthropogenic sources. Heavy metals pollution indices (Igeo > 5, EF > 40 and CF > 7) of both active and closed landfill precursors exceeded limits in the order of Zn > Cd > Pb > Cu > Ag, indicating a major potential health risk influenced by age and particle size of precursor. Zn, Cd, Cu and Pb of both landfill precursors exceeded the USEPA set standard for assessment of human health risk for each of the metals (1×10-4 to 1× 10-3). This study highlights the need for the integration of a clean-up process for precursors from both 24 types of landfill to reduce possible environmental pollution during a reuse process.
ChemInform, Dec 15, 2009
ABSTRACT
International Journal of Environmental Research, Jul 1, 2011
Development and optimisation of fast, efficient, quantitative, economic and environmentally frien... more Development and optimisation of fast, efficient, quantitative, economic and environmentally friendly analytical extraction techniques for the extraction clean up, and pre-concentration in the quantification of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in contaminated soils have been carried out. Three different extraction methods (Soxhlet, ultra sonication and mechanical shaking) were investigated on a low-level PAH soil certified reference material (CRM131-100) and the results were compared to determine the technique with the highest extraction efficiency. The clean up and pre-concentration procedures were optimized using both the conventional method (i.e. column packing with silica gel) as well as the solid phase extraction (SPE). Chromatographic conditions for the separation of PAHs using High Performance Liquid Chromatography (HPLC) using UV-DAD and fluorimetric detection with programmed excitation and emission wavelengths were also optimized. Six different extraction solvents: acetone, cyclohexane, 2-propanol, methanol, acetonitrile and dichloromethane, were tested to select the most suitable solvent for the extraction of the 16 PAHs from the certified soil reference material. Acetonitrile, dichloromethane and tetrahydrofuran were also tested as eluants for the optimisation of SPE clean up. The optimized ultrasonic extraction procedure utilizing four 15 minutes extraction cycles at 50 ºC and SPE clean up with tetrahydrofuran: acetonitrile (1:1) and subsequent separation by gradient reversed phase HPLC with fluorimetric detection extracted the PAHs from the certified reference material with recoveries ranging from 63.6 % to over 100 % .
Chemischer Informationsdienst, Jul 10, 1984
ChemInform, Oct 25, 1988
ChemInform Abstract By means of 1H NOE in (II) it is shown that bromination of (IIa) yields (III)... more ChemInform Abstract By means of 1H NOE in (II) it is shown that bromination of (IIa) yields (III) but nitration yields (IV) (all yields in g).
Chemischer Informationsdienst, Jul 10, 1984
![Research paper thumbnail of ChemInform Abstract: Stereoselective Deprotonation of α,β-Unsaturated Amides. γ-Silylated α,β-Unsaturated Amides. Formation by [1,5]Silicon Migration from O-Silylated Vinyl Ketene Aminals and Fluoride- and Lewis Acid-Mediated Aldol Condensations](https://attachments.academia-assets.com/112261447/thumbnails/1.jpg)
](Chemischer Informationsdienst, Jun 10, 1986
Stereoselective Deprotonation of Chiral and Achiral 2-Aminoalkyl Carbamates: Synthesis of Optical... more Stereoselective Deprotonation of Chiral and Achiral 2-Aminoalkyl Carbamates: Synthesis of Optically Active β-Amino Alcohols via 1-Oxy-Substituted Alkyllithium Intermediates.-The reaction sequence to the title alcohols, consisting of the deprotonation of sterically demanding carbamates like (I), (IV), (VIII), and (XI), and introduction of an electrophile (MeI, silyl-and stannyl chlorides, CO 2 , alkoxycarbonyl chlorides, acid chlorides, esters, aldehydes, and ketones) permits the diastereoselective, general synthesis of more complex, optically active β-amino-α-hydroxy derivatives. The stereochemistry of the lithiation is greatly influenced by the complexing amine. The substrate-directed selection between the diastereotopic α-pro-R and proS protons in the TMEDA-assisted deprotonation is largely shifted towards proS -selectivity in the presence of (-)-sparteine. For the removal of the carbamoyl residue, three methods are developed: first, cleavage of the aminoacetal moiety and subsequent alkaline hydrolysis of the intermediate carbamic acid ester, second, reflux in 5 N aq.
Soil and Sediment Contamination: An International Journal, Jul 12, 2018
The aim of this study was to carry out a bio-accessibility based risk assessment of polycyclic ar... more The aim of this study was to carry out a bio-accessibility based risk assessment of polycyclic aromatic hydrocarbon (PAHs) in soils from sites of different anthropogenic activities in Lagos, Nigeria. Using an in vitro gastrointestinal model-Fed Organic Estimation Human Simulation Test method (FOREShT)), the concentration of bio-accessible 16 priority US Environmental Protection Agency (USEPA) PAHs in soils were determined. Total concentration of 16 priority USEPA PAHs was also determined. The concentration range was 702 to 253,922 ng g-1 and 92-760 ng g-1 for total and bio-accessible PAHs respectively. For persons involved with activities at these sites no health risk were observed, based on bio-accessibility values of PAHs. Mean daily intake of PAHs from these soils were below the oral mean daily intake threshold for PAHs in food. Also, overall estimated theoretical cancer risk (2.
Journal of Emerging Trends in Engineering and Applied Sciences, Apr 1, 2012
March 2022
In this study, the levels of organochlorine pesticide (OCPs) in Ogun River, at Kara abattoir were... more In this study, the levels of organochlorine pesticide (OCPs) in Ogun River, at Kara abattoir were investigated to estimate the extent of pesticide pollution in the river. Two sets of water and sediment samples (A and B) were collected. Samples A were collected in April (during heavy downpour) and samples B in June (under dry weather condition). Most of the physico-chemical parameters in the water and sediment samples were within WHO limits, except the samples taken during heavy downpour. In the water samples, the DDT and metabolites (2.023±0.586 µg/L), endrin (0.671±0.256 µg/L) and aldrin and dieldrin (8.290±2.891 µg/L) exceeded 1 µg/L, 0.6 µg/L and 0.03 µg/L respectively in the WHO (2006) guideline, whereas lindane (0.046±0.034 µg/L) and methoxychlor (0.757±0.281 µg/L) were below 2 µg/L and 20 µg/L respectively in the guideline. OCP residual levels in samples A were much higher than in B. This could be attributed to the massive draining and heavy disturbance of the river during the...
Journal of Emerging Trends in Engineering and Applied Sciences, 2013
The Lagos lagoon is one of Africa's largest estuarine ecosystems. Its water receives organic ... more The Lagos lagoon is one of Africa's largest estuarine ecosystems. Its water receives organic input from a wide variety of sources; atmospheric, industrial, and municipal activities. Environmental impacts from PAHs continue to elicit global concern and attract attention especially in Lagos and its environs. Some PAH compounds which are toxic, mutagenic, or carcinogenic could be taken up and accumulated by aquatic organisms from polluted water, thereby resulting in the modern day diseases in humans. This research aims at assessing the decline of the water quality of Lagos lagoon due to land-based human activities in order to reveal the extent of exposure of humans to PAH risk. The research presents the need for control measures necessary for the minimization or prevention of PAH pollution to ensure a safe environment for our people. All the 16 USEPA priority PAHs were present across all twelve locations in high concentrations irrespective of the distance from the source point. The...
Food smoking belongs to one of the oldest technologies of food preservation which mankind has use... more Food smoking belongs to one of the oldest technologies of food preservation which mankind has used in fish processing. Potential health hazards associated with smoked foods may be caused by carcinogenic components of wood smoke – mainly polycyclic aromatic hydrocarbons (PAHs) and derivatives of PAH. Comparison of the concentration of PAHs in smoked fish samples processed by sawdust, charcoal and firewood were investigated with the aim of determining the process that contributed more concentration of the PAHs to the fish samples. For this study, three species of fishes were investigated: Arius heude loti (cat-fish), Cynoglossus senegalensis (sole) and Haake (fresh stock fish). The PAHs in the samples were extracted using solvents by ultrasonication and were analysed for the 16 US EPA polycyclic aromatic hydrocarbons using HPLC with a UV DAD detector. The results showed that smoked fish samples that were processed by charcoal gave the lowest level of total PAHs, followed by firewood m...
Research management review, 2018
While most universities in the developed world, by tradition, have research offices to handle res... more While most universities in the developed world, by tradition, have research offices to handle research management, structures for the efficient coordination and strong governance of research are nascent within many Sub-Saharan African universities. In this paper we look at the organizational structures, policies and functions of research offices for supporting faculty research as well as their management operations in 5 selected Nigerian universities. The authors interviewed 20 participants from 5 selected federal universities in Nigeria. Five directors of the research offices and 15 research administrators participated. Findings identified existing infrastructure for research management, the challenges facing newly created research offices in Nigerian universities, and strategies employed by research offices to tackle identified problems. Findings also showed how policies, practices, institutional structures and support models for research governance are shifting to align with inte...
Nigerian Journal of Environmental Sciences and Technology, Oct 1, 2020
Lagos is the largest producer of municipal solid waste in Nigeria, yet it is the smallest of Nige... more Lagos is the largest producer of municipal solid waste in Nigeria, yet it is the smallest of Nigeria's 36 states with the highest projected population, highest level of urbanization and it houses Nigeria's largest chief port, and principal economic and cultural centres. Out of the total waste generated, only about 73 percent actually got to the final disposal site. There is a possibility of inefficient and ineffective municipal solid waste management system in place which can damage the ecosystem services, contaminate ground and surface water, creates greenhouse gas emissions, increase disease transmission, damages ecosystem services and discourages tourism and other businesses. To this end, this study analysed the efficiency and effectiveness of solid waste services and; the efficiency and effectiveness of solid waste services in Lagos State using primary data and conducting statistical tests. The study found a general agreement on what constitutes efficient and effective solid waste services. However, the study concluded that the waste management system in Lagos State is inefficient, ineffective and therefore; unsustainable. The study therefore recommends among others the urgent need to reorganize the waste management institutions for effective and efficient performance. This requires substantial planning ability, appropriate equipment and continuous managerial optimization of vehicles and workers productivity, efficient vehicle routing, better designed vehicles, managerial incentives, faster vehicle repairs, vehicle standardization.
INTRODUCTION: Effective utility of mixed waste in the landfills lies before its complete degradat... more INTRODUCTION: Effective utility of mixed waste in the landfills lies before its complete degradation rather than after landfill closure. The elemental and chemical constituents of an active and a closed landfill composite were compared using Fourier transform - infrared (FTIR) spectroscopy, scanning electron microscope / energy-dispersive X-ray (SEM/EDX) spectroscopy, and proximate analysis in order to determine potential alternative uses. METHOD: Landfill sites were systematically gridded into seven cells according to RCRA USEPA guidelines. Three samples were obtained from each cell at upper (0-15cm), mid (16-35cm) and low- (36-50cm) depths, both during the dry and wet seasons. The dried samples were separated by size into composites of less degraded (S> 0.63mm) and more degraded (S<0.63mm) components and homogenised. Proximate parameters (ash, volatile and fixed carbon) of samples were determined by ASTM D3174-5 methods. An Alpha attenuated total reflectance -FTIR spectrometer (Bruker) and X-Max SEM/EDX Instruments were used to evaluate the functional and elemental properties. RESULTS: both landfills had similar major elemental constituents representing 96.5% and 98.4% of elemental composition for the closed (O > C > Si> Fe > Ca >Al) and active(C > O > Si > Al > Ca > Fe) landfill samples. Cluster analysis revealed that elemental similarities were more influenced by the level of composite degradation (more degraded / less degraded) than by depth or seasonal variations. FTIR absorption peaks of both landfill samples indicated mineralised waste constituent with some distinguishing peaks peculiar to each landfill. The average ash content (>51%) of the waste in both landfills was above the level considered suitable for energy recovery from waste. DISCUSSION: The absence of major organic peaks precludes use of the waste for soil enrichment and anaerobic digestion feeds, but not for landfill covering. These findings, from rapid and amenable spectroscopic techniques, inform strategic management decisions for landfills
Microwave acid digestion of solid samples combined with inductively coupled plasma – mass spectro... more Microwave acid digestion of solid samples combined with inductively coupled plasma – mass spectrometry (ICP-MS) provides a viable approach to quantification of heavy metals within landfill waste. The efficiency of Aqua regia and HNO3 in microwave digestion of both closed and active landfill composites was compared, with a view to relating heavy metals distribution to the particle size of the landfill composites. Landfill sites were systematically gridded into seven cells according to RCRA USEPA guidelines. Three samples were obtained from each cell at upper (0-15cm), mid (16-35cm) and low- (36-50cm) depths. The particle size was determined using the sieving method and grouped as less degraded (S> 0.63mm) and more degraded (S<0.63mm) components and homogenised. Microwave digestion of samples was carried according to the EPA3052 method using a CEM MARS Xpress digester. An Agilent 7500 ICP-MS was used to determined metal concentrations in digested samples. For 77% of the eleven USEPA toxic heavy metals investigated, microwave digestion with Aqua regia resulted in higher concentration of metals than with HNO3. Extraction precision for both acids was within acceptable limit for more degraded samples (RPD10%) a higher burden of heavy metals in closed landfill samples than active landfill samples, except for Ag and Zn. The more degraded component of both landfills had elevated concentrations of heavy metals (>4% for HNO3 and >6% for Aqua regia). Sample recoveries based on CRM analysis showed that both acids were within the same accuracy (between 88% and 95%
Waste Management & Research, Jul 30, 2018
Landfills' heterogeneous composites waste were evaluated as precursors for generation of activate... more Landfills' heterogeneous composites waste were evaluated as precursors for generation of activated carbon (AC). A single step chemical activation process was applied involving irradiation with microwave energy and impregnation with KOH. The average percentage yield of AC from active landfill precursor was higher than that from closed landfill for all depths sampled. Increase in impregnation ratio and irradiation power decreased the average percentage yield for both landfill precursors (Active: 38.1 to 33.1%) (Closed 42.1: to 33.3%). The optimum pH range for adsorption of methylene blue was pH 6-7, while adsorption increased with increase in temperature over the range 30 to 50 o C. Carbonyl and hydroxyl groups were the major functional groups on the surface of AC. The properties of the AC are potentially suitable for the removal of cationic dyes and pollutants. AC generated from the landfill composite were comparable to that from some other biomass being managed through AC generation. This is the first report to demonstrate the possible reuse of landfill composite as AC. The reuse option of landfill composite could provide a means of sustainable management of landfilled municipal waste.
Waste Management, Aug 1, 2018
Multivariate analysis of a heavy metal pollution survey of closed and active landfill precursors ... more Multivariate analysis of a heavy metal pollution survey of closed and active landfill precursors was carried out in order to compare environmental risk levels in relation to age, particle size and depth of the precursors. Landfill precursors (77) were collected and analyzed for 15 USEPA toxic heavy metals using ICP-MS. Heavy metals concentrations in closed landfill precursors were significantly higher than those in the active landfill for 11 of 15 heavy metals investigated (closed landfill order: Fe > Al > Mn > Cu > Pb > Ba> Co > Cr > Ni > Cd 15 > As > Se > Ti). Cluster analysis and correlation studies indicated the distribution of the metals was more influenced by landfill precursor size than by depth of the sample. Principal component analysis (PCA) showed that 10 of 15 of heavy metals of both landfill precursors were from similar anthropogenic sources. Heavy metals pollution indices (Igeo > 5, EF > 40 and CF > 7) of both active and closed landfill precursors exceeded limits in the order of Zn > Cd > Pb > Cu > Ag, indicating a major potential health risk influenced by age and particle size of precursor. Zn, Cd, Cu and Pb of both landfill precursors exceeded the USEPA set standard for assessment of human health risk for each of the metals (1×10-4 to 1× 10-3). This study highlights the need for the integration of a clean-up process for precursors from both 24 types of landfill to reduce possible environmental pollution during a reuse process.
ChemInform, Dec 15, 2009
ABSTRACT
International Journal of Environmental Research, Jul 1, 2011
Development and optimisation of fast, efficient, quantitative, economic and environmentally frien... more Development and optimisation of fast, efficient, quantitative, economic and environmentally friendly analytical extraction techniques for the extraction clean up, and pre-concentration in the quantification of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in contaminated soils have been carried out. Three different extraction methods (Soxhlet, ultra sonication and mechanical shaking) were investigated on a low-level PAH soil certified reference material (CRM131-100) and the results were compared to determine the technique with the highest extraction efficiency. The clean up and pre-concentration procedures were optimized using both the conventional method (i.e. column packing with silica gel) as well as the solid phase extraction (SPE). Chromatographic conditions for the separation of PAHs using High Performance Liquid Chromatography (HPLC) using UV-DAD and fluorimetric detection with programmed excitation and emission wavelengths were also optimized. Six different extraction solvents: acetone, cyclohexane, 2-propanol, methanol, acetonitrile and dichloromethane, were tested to select the most suitable solvent for the extraction of the 16 PAHs from the certified soil reference material. Acetonitrile, dichloromethane and tetrahydrofuran were also tested as eluants for the optimisation of SPE clean up. The optimized ultrasonic extraction procedure utilizing four 15 minutes extraction cycles at 50 ºC and SPE clean up with tetrahydrofuran: acetonitrile (1:1) and subsequent separation by gradient reversed phase HPLC with fluorimetric detection extracted the PAHs from the certified reference material with recoveries ranging from 63.6 % to over 100 % .
Chemischer Informationsdienst, Jul 10, 1984
ChemInform, Oct 25, 1988
ChemInform Abstract By means of 1H NOE in (II) it is shown that bromination of (IIa) yields (III)... more ChemInform Abstract By means of 1H NOE in (II) it is shown that bromination of (IIa) yields (III) but nitration yields (IV) (all yields in g).
Chemischer Informationsdienst, Jul 10, 1984
Chemischer Informationsdienst, Jun 10, 1986
Stereoselective Deprotonation of Chiral and Achiral 2-Aminoalkyl Carbamates: Synthesis of Optical... more Stereoselective Deprotonation of Chiral and Achiral 2-Aminoalkyl Carbamates: Synthesis of Optically Active β-Amino Alcohols via 1-Oxy-Substituted Alkyllithium Intermediates.-The reaction sequence to the title alcohols, consisting of the deprotonation of sterically demanding carbamates like (I), (IV), (VIII), and (XI), and introduction of an electrophile (MeI, silyl-and stannyl chlorides, CO 2 , alkoxycarbonyl chlorides, acid chlorides, esters, aldehydes, and ketones) permits the diastereoselective, general synthesis of more complex, optically active β-amino-α-hydroxy derivatives. The stereochemistry of the lithiation is greatly influenced by the complexing amine. The substrate-directed selection between the diastereotopic α-pro-R and proS protons in the TMEDA-assisted deprotonation is largely shifted towards proS -selectivity in the presence of (-)-sparteine. For the removal of the carbamoyl residue, three methods are developed: first, cleavage of the aminoacetal moiety and subsequent alkaline hydrolysis of the intermediate carbamic acid ester, second, reflux in 5 N aq.
Soil and Sediment Contamination: An International Journal, Jul 12, 2018
The aim of this study was to carry out a bio-accessibility based risk assessment of polycyclic ar... more The aim of this study was to carry out a bio-accessibility based risk assessment of polycyclic aromatic hydrocarbon (PAHs) in soils from sites of different anthropogenic activities in Lagos, Nigeria. Using an in vitro gastrointestinal model-Fed Organic Estimation Human Simulation Test method (FOREShT)), the concentration of bio-accessible 16 priority US Environmental Protection Agency (USEPA) PAHs in soils were determined. Total concentration of 16 priority USEPA PAHs was also determined. The concentration range was 702 to 253,922 ng g-1 and 92-760 ng g-1 for total and bio-accessible PAHs respectively. For persons involved with activities at these sites no health risk were observed, based on bio-accessibility values of PAHs. Mean daily intake of PAHs from these soils were below the oral mean daily intake threshold for PAHs in food. Also, overall estimated theoretical cancer risk (2.
Journal of Emerging Trends in Engineering and Applied Sciences, Apr 1, 2012
March 2022
In this study, the levels of organochlorine pesticide (OCPs) in Ogun River, at Kara abattoir were... more In this study, the levels of organochlorine pesticide (OCPs) in Ogun River, at Kara abattoir were investigated to estimate the extent of pesticide pollution in the river. Two sets of water and sediment samples (A and B) were collected. Samples A were collected in April (during heavy downpour) and samples B in June (under dry weather condition). Most of the physico-chemical parameters in the water and sediment samples were within WHO limits, except the samples taken during heavy downpour. In the water samples, the DDT and metabolites (2.023±0.586 µg/L), endrin (0.671±0.256 µg/L) and aldrin and dieldrin (8.290±2.891 µg/L) exceeded 1 µg/L, 0.6 µg/L and 0.03 µg/L respectively in the WHO (2006) guideline, whereas lindane (0.046±0.034 µg/L) and methoxychlor (0.757±0.281 µg/L) were below 2 µg/L and 20 µg/L respectively in the guideline. OCP residual levels in samples A were much higher than in B. This could be attributed to the massive draining and heavy disturbance of the river during the...
Journal of Emerging Trends in Engineering and Applied Sciences, 2013
The Lagos lagoon is one of Africa's largest estuarine ecosystems. Its water receives organic ... more The Lagos lagoon is one of Africa's largest estuarine ecosystems. Its water receives organic input from a wide variety of sources; atmospheric, industrial, and municipal activities. Environmental impacts from PAHs continue to elicit global concern and attract attention especially in Lagos and its environs. Some PAH compounds which are toxic, mutagenic, or carcinogenic could be taken up and accumulated by aquatic organisms from polluted water, thereby resulting in the modern day diseases in humans. This research aims at assessing the decline of the water quality of Lagos lagoon due to land-based human activities in order to reveal the extent of exposure of humans to PAH risk. The research presents the need for control measures necessary for the minimization or prevention of PAH pollution to ensure a safe environment for our people. All the 16 USEPA priority PAHs were present across all twelve locations in high concentrations irrespective of the distance from the source point. The...
Food smoking belongs to one of the oldest technologies of food preservation which mankind has use... more Food smoking belongs to one of the oldest technologies of food preservation which mankind has used in fish processing. Potential health hazards associated with smoked foods may be caused by carcinogenic components of wood smoke – mainly polycyclic aromatic hydrocarbons (PAHs) and derivatives of PAH. Comparison of the concentration of PAHs in smoked fish samples processed by sawdust, charcoal and firewood were investigated with the aim of determining the process that contributed more concentration of the PAHs to the fish samples. For this study, three species of fishes were investigated: Arius heude loti (cat-fish), Cynoglossus senegalensis (sole) and Haake (fresh stock fish). The PAHs in the samples were extracted using solvents by ultrasonication and were analysed for the 16 US EPA polycyclic aromatic hydrocarbons using HPLC with a UV DAD detector. The results showed that smoked fish samples that were processed by charcoal gave the lowest level of total PAHs, followed by firewood m...
Research management review, 2018
While most universities in the developed world, by tradition, have research offices to handle res... more While most universities in the developed world, by tradition, have research offices to handle research management, structures for the efficient coordination and strong governance of research are nascent within many Sub-Saharan African universities. In this paper we look at the organizational structures, policies and functions of research offices for supporting faculty research as well as their management operations in 5 selected Nigerian universities. The authors interviewed 20 participants from 5 selected federal universities in Nigeria. Five directors of the research offices and 15 research administrators participated. Findings identified existing infrastructure for research management, the challenges facing newly created research offices in Nigerian universities, and strategies employed by research offices to tackle identified problems. Findings also showed how policies, practices, institutional structures and support models for research governance are shifting to align with inte...