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Open Access
A mathematical model for explosions with chain branching and chain breaking kinetics
(Department of Mathematical Obafemi Awolowo University, 1989) Samuel Segun OKOYA
A mathematical model for explosions with chain branching and chain breaking kinetics is presented in this thesis to give further insight into the theory of combustion reactions under physically reasonable assumptions.
Embargo
A study of distributed lag model using koyck and almon techniques
(Department of Mathematics, Falculty of Science, Obafemi Awolowo University, Ile-Ife., 2024) Toyin, Kayode Ajetunmobi.
This study evaluated the effects of the choice of optimal truncation lag-length, determined the effects of multicollinearity and choice of approximating polynomial, and compared the efficiency of Almon and Koyck estimators. These were with a view to providing information on the effects of multicollinearity, choice of optimal truncation lag-length and choice of approximating polynomial on parameter estimation of Koyck and Almon distributed lag models. The study conducted a comprehensive time series analysis using monthly exchange rates (Naira-Dollar, Naira-Pound and Naira-Euro) and Inflation rate data from Central Bank of Nigeria over the period of January 2004 and April 2021 for Koyck Distributed Lag Model and Almon Distributed Lag Model. R Software Package was used to analyze the data for both models, while varying the order of approximating polynomials (k) and lags (q) with the condition that, degree of polynomial is less that number of lags. The research work employed standard procedure such as statistical significance, information criteria to determine the op timal truncation lag-length required for the implementation of distributed lag models. For the measure of multicollinearity in distributed lag models, Variance inflation factor was also used to determine severity of multicollinearity in the distributed lag models. The efficiency of Koyck and Almon estimators were compared using standard error The results of the study showed that Koyck estimator is preferable to Almon estimator due to lower standard error of Koyck estimators which indicate better precision of estimates. However, Almon estimators are preferable to Koyck estimators given the higher values of variance inflation factors (VIF) of Koyck estimator. To avoid problem of multicollinearity, the Almon estimator is the better choice. The study concluded that polynomial of order 2 is the best approximating polynomial for Almon distributed lag model and that Koyck estimators have higher precision in parameter estimation than Almon estimators.
Open Access
A study of heavy metal speciation and free fatty acid levels of the Obafemi Awolowo University's sewage treatment oxidation pond and its receiving stream
(Department of Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria., 2015) Obisanya, Joshua Funminiyi
Levels of different metal species and free fatty acids (FFAs) of a sewage treatment oxidation pond (STOP) of the Obafemi Awolowo University and its receiving stream were assessed. This was with a view to appraising the effectiveness of the pond in removing heavy metals, establishing the quality of water at downstream, and the potential toxicity of water and sediment of the study area.
Open Access
A survey of ascaris lumbricodes infection among school age children in Ikirun , Osun State Nigeria.
(Department of Zoology, Faculty of Science Obafemi Awolowo University., 2022) FASANMI Oluwafunmilayo Blessing
This study determined the prevalence and intensity of infection of Ascaris lumbricoides and other soil transmitted helminths among school-age children, examined soil samples obtained from children environment for Ascaris eggs, surveyed on anthelminthic treatment and type of sanitation available to the school-age children in Ikirun, Osun State, Nigeria. These were with a view to providing information on the risk factors affecting the transmission of soil helminths among the school–age children in the study area. Stool samples were collected from 332 primary school pupils comprising 135 males (40.7%) and 197 females (59.3%), between the ages of 6 and 12 from July to October 2018. The stool samples were analysed using applicator stick and about 5 g faecal sample was collected from each pupil into clean and well-labelled universal sample bottle. The faecal samples were preserved with 2 ml of 10% formalin. Soil samples were also collected from around the school latrine, playground, classroom and residence of each pupil into a properly labelled polythene bag. The preserved faecal samples were later processed by modified Kato-katz techinique and the soil samples by centrifugal floatation techniques using sucrose solution at the Parasitology Laboratory of the Department of Zoology, Obafemi Awolowo University, Ile–Ife. This was to determine the presence and number of Ascaris and other helminths eggs. The helminth eggs were identified based on morphological parameters. Data were analyzed using chi square and multivariate logistic regression from Statistical Package for Social Sciences (SPSS) version 17. The results of the study showed that out of the 332 faecal samples examined, 152 (45.8%) were positive for helminth eggs. The various helminth eggs observed and their prevalences were Ascaris lumbricoides (40.1%), hookworms (8.7%) and Trichuristrichiura (3.3%). Multiple infections were observed among 17(5.1%) of the pupils. The sex related prevalence was higher among females (48.2%) than males (42.2%). The prevalence of A. lumbricoides was highest among the children of age group 6-8 years (50.0%) and lowest (27.5%) among the children over 12 years of age. There was no significant difference (p > 0.05) in prevalence rates of different STHs infections in relation to age groups and gender across schools. The intensity of A. lumbricoides, hookworms and T. trichiura determined as mean egg count/gram of faeces were 733.77 ± 81.85, 20.05 ± 4.65 and 1.23 ± 0.43 respectively. A total of 88 helminth eggs (58.7%) were collected out of the 150 soil samples collected. The helminth eggs identified were Ascaris lumbricoides, 41.3%; Toxocara canis, 24.0%; Trichuris trichiura 9.3% and hookworms 6.7%. The intensities of A. lumbricoides, T. canis, T. trichiura and hookworms per 30 g soil were 100.16 ±15.71, 18.24 ± 6.33, 2.08 ± 0.553and 16.05 ± 4.46 respectively. The rate of contamination of soil was higher near latrines (67.4%) and lower around the classrooms (48.6%). The study concluded that Ascaris lumbricoides remains a public health concern among children in the study area. Provision of potable water, toilet facilities and regular de-worming will enhance control measures.
Open Access
ADEBAYO E .B (2022) Comparative assessment of plant-based extracts and synthetic insecticides on the growth, yield and proximate composition of cowpea (vigna unguiculata l. walp) institute of ecology and environmental studies, Faculty of Science, Obafemi Awolowo University.
(Institute of ecology and environmental studies, Faculty of Science, Obafemi Awolowo University., 2022) FOYINSOLAMI Ebunoluwa Adebayo
This study assessed the effect of plant-based and synthetic insecticides application on the growth response and yield of cowpea. It also investigated the effects of the insecticides application on the biomass, grain yield and proximate composition of cowpea grains produced. These were with a view to providing information on the use of plant-based extracts on quantity and quality of cowpea grains. The experiment was conducted on a vacant land measuring 11.75 m x 7.50 m behind the Institute of Ecology and Environmental Studies, Obafemi Awolowo University, Ile-Ife. Viable seeds of Ife-brown cultivar of cowpea were purchased from the Institute of Agricultural Research and Training, Ibadan. The experimental location was cleared manually two times using a cutlass and hand-held hoe. The experiment consisted of four treatments which were: extracts of three plant-based (Azadirachta indica, Tithonia diversifolia, Chromolaena odorata) and cypermethrin that served as control. The extracts of fresh shoots of A. indica, T. diversifolia, and C. odorata were separately prepared using standard method. The experiment was made up of 12 plots, each measuring 1.5 m x 2.0 m and the plots were arranged in a randomized complete block design. Four seeds per stand were sown using 50 cm x 30 cm spacing and seedlings thinned to 2 stands per hole at 2 weeks after sowing (WAS). The plots were weeded at 3 and 6 WAS. The cowpea stands were sprayed with plant-based and cypermethrin using the rates 100 g/L/plot and 15 mL/L/plot respectively at 5, 6, 7 and 8 WAS. Growth parameters such as plant height, number of leaves and stem girth were measured bi-weekly from 2 to 8 WAS and extent of leaf damage at 7 and 8 WAS. Tagged cowpea stands were carefully uprooted at 10 WAS to determine the total biomass yield. Cowpea pods were harvested when the pods turned yellow at 10 WAS and threshed. Proximate composition of cowpea grains (crude protein, ash, fibre, carbohydrate, fat and dry matter), preand post-cropped soil analyses were carried out using standard methods. Data obtained were subjected to analysis of variance and their treatment means were separated using Tukey’s multiple comparison test at p < 0.05. The results showed that pH of the pre-cropped soil was 6.94 and soil texture was loamy sand. Organic carbon and total nitrogen were 0.64 and 5.82 g/kg, respectively and these values reduced to between 13 and 30% across the treatment plots for the post-cropped soil. The growth parameters; height (cm), number of leaves and stem girth (cm) at 6 WAS were: 23.06 ± 0.86, 55.29 ± 4.59 and 1.58 ± 0.05 for A. indica; 24.15 ± 0.75, 57.58 ± 3.94 and 1.69 ± 0.06 for T. diversifolia; 21.76 ± 0.68, 48.38 ± 2.15 and 1.55 ± 0.05 for C. odorata; and 21.99 ± 1.18, 45.26 ± 3.45 and 1.46 ± 0.07 for cypermethrin, respectively. Also, the grain yield of cowpea with cypermethrin, 1.08 t/ha was significantly (p < 0.05) higher than the best plant-based insecticide, T. diversifolia. Cowpea grains obtained with T. diversifolia and C. odorata had comparable and high values of crude protein (29.7%, 28.3%) and fibre (6.1%, 6.5%) respectively. The study concluded that T. diversifolia compared favourably with cypermethrin, in terms of grain yield of cowpea, whereas T. diversifolia and C. odorata gave higher proximate composition of cowpea.
Open Access
An evaluation of the Nigerian innovation system and technoloical capability building in the manufacturing sector.
(Department of Technology Management Obafemi Awolowo University, 2005) OKE, Joseph Sunday
This study evaluated the knowledge generation and utilization performance and the operational environment of the Nigerian innovation system with the aim of establishing the level of technological capability building in the manufacturing sector. In conclusion, the Nigerian innovation system was generally too weak to support sufficient technological capability building in the manufacturing sector due to factors such as low spending on R&D, low level of S&T human resources , poor state of research facilities and poor linkage between academic /research institution and firms.
Open Access
Analysis of batch arrivals with multiple service for unbalanced queueing systems
(Department of Mathematics, Faculty of Science ,Obafemi Awolowo University ,Ile -Ife, 0222) Babalola, Ajiboye Reginald
This study designed a prototype of an unbalanced Combined Input Crosspoint Queued (CICQ) queueing system, obtained the possible states at the moment just before a departure for some specific gridpoints and provided the system solution in terms of those grid points and analysed the performanceof the proposed system. These were with a view to establishing relevant flow balance equations and analysing the traffic at various levels of interactions of contending units for congestion, complexity and grid points. Considered is a two-stream toll gate system modified from the CICQ switch system of homogeneous and heterogeneous packets. The Markov Modulated Poisson Process (MMPP) were superimposed at the input port to obtain the defined states at (u, v,w)k for epoch or moments just after a departure of type k which identified admissible states and their transition probability matrix was obtained using various combinatorial reasonings. The work thereafter, formulated governing equations from relevant flow balance equations, which were of the form ΠP = Π and solved them for stationary probability vectors. Subsequently, the work obtained the mean recurrence times for each state and mean first passage times from one state to the other. Highlighted in particular, were the situations of the extreme cases of heavy traffic (HT) with 27 possible states when the system was saturated with contending units and two cases of restricted light traffic. The restricted traffic was such that traffic (u, v,w) at the moment just before a departure, was guided by the conditions u ≤ 2n, v ≤ 2n, w ≤ n and v+w ≤ 2n where u, v,w and n were integers connoting number of different units in the queues. The light traffic case I (LTS I) connoted n = 1 with 17 admissible states and the light traffic case II (LTS II) connoted n = 2 with 86 admissible states for a 27 grid point system. For a combination of service times τ1, τ2, τ3, the resulting combination were evaluated for cohersion, stability and efficiency using measures of the minimum mean first passage times Tmin(ijk), Concentration Index (C) and the Euclidean Distance Measure (dI/II ). The result from the mean first passage time for all three systems provided a measure of the sensitivity for the stationary probability vectors as defined in their respective underlying states. The mean first passage times tijk was found to be a stochastic process of its own with respect to each of the models, matrices and values, in correspondence to the gridpoints as defined by the parameters of the light traffic case I (LTSI), light traffic case II (LTSII) and the heavy traffic situations (HTS). Thetendency to concentrate (or dominate) on any state is lower for the heavy traffic, though steady, but cannot be sustained when compared with the light traffic cases. This tendency for concentration was found to be closer for both light traffic cases but the LTS II case was uniformly less concentrated than that of the LTS I case. The order, therefore, of the concentration Index C for the three systems is HTS < LTS II < LTS I by considering all the grid points. The value of the concentration index C for the heavy traffic ranges from 0.047 to 0.05, that of the LTS II ranges from 0.07 to 0.35 while the one for LTS I ranges from 0.08 to 0.37. The minimum Euclidean distance (dI/II ) compared to the restrictive light traffic cases, in relation to matching similar states, is wide. The width is in the multiple of 104. The least active destination states service type III has the lowest value of 4.34, while the most active destination state for service type III has a value of 6.42. It was noted that the minimum Euclidean distance dI/II appeared progressive as the destination states increases. However, the order of spryness for the three types of service is service type I > service type II > service type III. The study concluded that the Combined Input Crosspoint Queued switch model is able to predict relative performances of traffic systems based on the objective matrix for different levels of complexity and congestion.
Open Access
Analytic solutions of heat transfer problems with generalised arrhenius reaction rate in three symmetric geometries.
(Faculty of Science, Department of Mathematics, Obafemi Awolowo University., 2023) ADEBOWALE, Folasade Bolanle
This study formulated the one- dimensional thermal balance equation for a chemical substance at rest in three geometric under constant surface surface temperature and Newtonian cooling; Obtained analytical solution of the formulated thermal balance equation under realistic conditions; and examined the effects of constant surface temperature, the exponent of pre-exponential factor and biot number on criticality and transition. these were with a view to generalizing existing works in the literature on thermal explosion criticality and transition.
Open Access
Analytical solution of heat transfer problems with generalised Arrhenius reaction rate in three symmetric geometries
(Department of Mathematics, Faculty of Science, Obafemi Awolowo University., 2023) ADEBOWALE, Folashade Bolanle
This study formulated the one-dimensional thermal balance equation for a a chemical substance at rest in three geometries under constant surface temperature and newtonian cooling obtained analytical solution of the formulated thermal balance equation under realistic condition and examined the effects of constant surface temperature . the exponent of the pre exponential factor and biot number on criticality and transition .these were with a view to generalizing existing works in the literature on thermal explosion, criticality and transition
Open Access
Antibiotic susceptibility and molecular analysis of staphylicoccus aureus from nasal samples of west african dwarf goats (Capra hircus) in Osun State, Nigeria.
(Department of Microbiology, Faculty of Sciences, Obafemi Awolowo University., 2022) TAIWO, Fadekemi Funmilayo
This study isolated and identified Staphylococcus aureus from the anterior nares of West African Dwarf (WAD) goat in Osun State, Nigeria, determined the antibiotic susceptibility pattern of S. aureus isolates and identified methicillin-resistant S. aureus (MRSA) isolates and Panton Valentine Leukocidin gene. It also investigated the population structure of S. aureus from the nasal samples of the WAD goats. These were with a view to providing information on the prevalence, antibiotic susceptibility pattern, and clonal nature of S. aureus from the nasal samples of WAD goats.
Open Access
Assesement of Heavy Metal Content and Health Impact of Classroom Dusts on Lower Level Primary School Children in Southwestern Nigeria
(Department of Chemistry, Falculty of science, Obafemi Awolowo University, ile-ife Niigeria., 2023) ASEPERI, Dare Joseph
This study determined the bioavailable concentration of heavy metals in deposited classroom dust, evaluated the potential sources of the heavy metals. It further estimated the possible health risk of exposure to heavy metals in classroom dust. These were with a view to providing information on the health issues that could be associated with exposure of school children to heavy metals. A total of 36 composite dust samples were collected from classrooms of nursery and lower-level primary schools in Ondo and Ile-Ife towns, and their environs in Southwestern part of Nigeria. The samples were subjected to a four-stage sequential extraction protocols in order to extract the bioavailable metals from the dust samples. All the samples were analyzed for total metals and bioavailable metals using Energy .Dispersive X-Ray Fluorescence (EDXRF) Spectrometer. The effectiveness of the sequential extraction procedure was determined by recovery analyses based on comparison of the sequential analysis results with the total metal concentration in the samples. The accuracy of the instrument was determined with analysis of a standard reference soil sample (SRM 1646a) while precision was assessed using replicate sample analysis. The average percentage recovery (%R) values were done by comparing the sum of the fractions (F1 – F4) to total metal concentrations. The results showed %R values that ranged from 85.77% Cd to 98.52% Cu. Also, the values of the reference soil material for the metals agreed well with the obtained values. The overall mean concentration of total metal was in the order Fe > Al > Co > Zn > Mn > Pb > Cu > Ni > As > Ag > V > Cr > Cd with Fe having the highest concentration (166,875.37 ± 43,550.60 mgkg-1) and Cd with the lowest concentration (3.34 ± 5.49 mgkg-1). The distribution of metals in the sequential extraction showed the prominence of Cd (32.61%) and Ag (25.29%) in the soluble exchangeable fraction (F1), Mn (44.28%), and Zn (30.19%) in the carbonates, oxides, and a reducible fraction (F2). Elements Cd, Ag, Zn, Mn, Cu, and Pb had better spread in the four fractions (F1-F4). The Bioavailability Index showed that Mn, Ni, Ag and Cd were potentially bioavailable from the three traffic volume categories while Al, V, Cr, Co, Fe, Cu, Zn, As and Pb were biounavailable (<0.2). The hazard index indicated possibility for non-cancer risk for elements Fe, Ni, Cu, Zn, As, Pb, Ag and Cd while Al would pose no threat. There was indication for the possibility of cancer risk for Ni, Pb and Cd. The contamination factor showed that the dust samples were highly contaminated. The geoaccumulation index showed intense pollution caused by Ni, Cu, Zn and Pb. The receptor model (PMF 5.0) identified two major possible sources which include the vehicular emissions and mixed sources to indicate high anthropogenic activities. This study concluded that there was a possibility of human health problems considering the contribution of bioavailable heavy metals in the polluted classroom environment, hence the need to minimize contact to heavy metals carried by dust.
Open Access
Assessement of level of radioactivity and potentially toxic elements in locally pulverized plantain (musa paradislacal.) obtained from osun east senatorial district, Nigeria
(The Institute of Ecology and Environmental Studies, Faculty of Science, Obafemi Awolowo University., 2022) ABE, Toluwase Patience
This study assessed the concentrations of potentially toxic elements in the locally produced plantain flour. It also determined the radioactivity levels in the locally produced flour and assessed the human health risk associated with the contaminants. These were with a view to providing information on the concentrations and health risks of the potentially toxic elements and radionuclides in locally produced plantain flour in the study area. Potentially toxic elements were identified by using Proton/Particle Induced X-ray Emission Spectrometry. Correlation, principal component and cluster analyses suggested probable natural and anthropogenic sources of the elements in the pulverized plantain. The Human Health-Risk Assessment of toxic elements was assessed on the basis of geo-Estimated Daily Intake (EDI), Hazard Index (HI), Hazard Quotient (HQ), Carcinogenic Health Effect (Cr) and Ingestion Cancer Slope Factors. Gamma Ray Spectrometer was used to profile 238U, 232Th, and 40K levels in the samples. Activity Concentrations, Radium equivalent activity concentration index (Raeq), Absorbed Gamma Dose Rate (ADR), External Hazard Index (Hex), Internal Hazard Index (Hin), Excess Lifetime Cancer Risk (ELCR) and Annual Effective Dose Equivalent (AEDE) were subsequently evaluated. Twenty-seven elements were detected in the pulverized plantain samples and their concentrations determined. The concentration of elements analyzed in the pulverized plantain samples is in the order K > Cl > Mg > P > Sr > Ca > S > Si > Cd > Rb > Mo > Fe > Al > Ba > Br > Ti > Pb > Bi > Mn > Na > Ni > Cu > Cr > Sc > Zn > As > Co. The analysis of HI revealed extremely health risk. HQ values are lower than the Recommended value > 1 except Cu, Co, Ba, Cd, Pb and As which are comparatively higher. In the test pulverized plantain sample, the mean xvii activity concentrations of 40K, 232Th and 238U are 117.73 ± 2.52 Bq/kg, 1.66 ± 1.85 Bq/kg and 17.85 ± 17.61 Bq/kg respectively. For the control pulverized plantain samples, the mean activity concentrations of 40K, 232Th and 238U are 11.05±0.43 Bq/kg, 0.37±0.01 Bq/kg and 3.89±0.25 Bq/kg respectively. Although the ELCR calculated shows higher values compared to acceptable value of 2.9 x 10-3 stipulated by UNSCEAR the values of ADR, Raeq, Hex and Hin were significantly lower than or matched well with the permissible values indicating consumption safety for those who do not rely heavily on the consumption of pulverized plantain. The study concluded that the samples from the open markets of the study areas were contaminated with toxic elements, and could at long last pose major health problems to the consumers. However, the results obtained from the radioactivity level of the plantain were below their standard permissible limits. These assessments confirmed that the test pulverized plantain samples exhibited low gamma radiation
Open Access
Assessment of ecosystem services of Ikogosi warm spring, Ikogosi and Olumirin waterfall, Erin- Ijesa, Southwest, Nigeria.
(Department of Ecology and Enivronmental studies, Faculty of science,Obafemi Awolowo University., 2023) Olusola, Johnson Adedeji
This study profiled the ecosystem services offered by Ikogosi Warm Spring and Olumirin Waterfall, valued the ecosystem services and benefits offered by Ikogosi Warm Spring and Olumirin Waterfall and compared ecosystem services offered between and within the study areas. The study also developed support tools for the management and sustenance of Ikogosi Warm Spring and Olumirin Waterfall. These were with a view to providing a database on the services and benefits offered by these ecosystems and give information on the drivers of ecosystem degradation that have been eroding these values The study was conducted in two phases: field survey and laboratory investigation. Soil and water samples were collected using standard methods to determine their physicochemical parameters. Ecosystem services were evaluated using the carbon tax and industrial oxygen price methods for carbon sequestration and oxygen regulatory services. The market valuation method was used to determine water provisioning services. Travel cost methods were used to estimate cultural benefits. The total ecosystem services of the study areas in monetary terms were calculated by adding carbon sequestration and oxygen potential, water storage capacity, water purification, nutrient cycling, erosion prevention, water consumption, and recreational values. The ecosystem service values of the two sites were then compared. A participatory framework approach was used to develop support tools for managing and sustaining resources of the study areas. Pearson correlation was used to find relationship between the variables while qualitative data was analysed using a thematic approach. The study identified four ecosystem services in the study areas. The total ecosystem services estimated in 2022 was US$132.19 million. Ikogosi Warm Spring contributedUS$ 78.37 million, while the contribution of Olumirin Waterfall was US$ 53.82 million. The contributions of individual ecosystem services at Ikogosi Warm Spring were carbon sequestration (43.8%) >water regulation (29.93%)> water purification (15.96%) > oxygen potential (6.93%), >nutrient recycling (3.23%) > erosion prevention (0.09%). For Olumirin waterfall, the level of contributions of individual ecosystem services was carbon sequestration (39.94%) >water regulation (39.01%) >oxygen potential (13.98%) >water purification (2.75%) > erosion prevention (0.11%). Soil chemical characteristics of the study areas were total nitrogen 8.40 g/kg (Ikogosi Warm Spring), 7.00 g/kg (Olumirin Waterfalls); organic matter 58.00 g/kg (Ikogosi Warm Spring), 26.00 g/kg (Olumirin Waterfalls); available phosphorus 0.80 mg/kg (Ikogosi Warm Spring) and 0.54 m/kg (Olumirin Waterfalls). The water alkalinity was 0.15 mg /l (Ikogosi Warm Spring), 2.40 mg/l (Olumirin Waterfalls); total dissolved solids 0.03 mg/l (Ikogosi Warm Spring), 171.60 mg /l (Olumirin Waterfalls); total hardness 1.13 mg/l (Ikogosi Warm Spring), 0.95 mg/l (Olumirin Waterfalls); turbidity 10.81 (NTU) (Ikogosi Warm Spring), 0.80 NTU (Olumirin Waterfalls) and electrical conductivity 12.06 (μS/cm) (Ikogosi Warm Spring), 1.10 (μS/cm) (Olumirin Waterfalls), Ca2+ (3.44) (mg/l) (Ikogosi Warm Spring), 0.10 (mg/l) (Olumirin Waterfalls); Mg2+ (1.23) (mg/l) (Ikogosi Warm Spring), 0.25 (mg/l) (Olumirin Waterfalls) and dissolved oxygen, 0.25 (mg/l) (Ikogosi Warm Spring), 0.05 (mg/l) (Olumirin Waterfalls) . All the water samples results were below the permissible limits. Focus Group Discussion (FGD) and in-depth interviews from the study showed the negligence of local communities in the sustenance and management of tourist destinations. This study concluded that land use and deforestation were the drivers of ecosystem degradation in the study areas.
Open Access
ASSESSMENT OF LEVELS OF RADIOACTIVITY AND POTENTIALLY TOXIC ELEMENTS IN LOCALLY PULVERIZED PLANTAIN (MUSA PARADISIACA L.) OBTAINED FROM OSUN EAST SENATORIAL DISTRICT, NIGERIA
(INSTITUTE OF ECOLOGY AND ENVIRONMENTAL STUDIES, FACULTY OF SCIENCE, OBAFEMI AWOLOWO UNIVERSITY., 2022) TOLUWASE PATIENCE ABE
This study assessed the concentrations of potentially toxic elements in the locally produced plantain flour. It also determined the radioactivity levels in the locally produced flour and assessed the human health risk associated with the contaminants. These were with a view to providing information on the concentrations and health risks of the potentially toxic elements and radionuclides in locally produced plantain flour in the study area. Potentially toxic elements were identified by using Proton/Particle Induced X-ray Emission Spectrometry. Correlation, principal component and cluster analyses suggested probable natural and anthropogenic sources of the elements in the pulverized plantain. The Human Health-Risk Assessment of toxic elements was assessed on the basis of geo-Estimated Daily Intake (EDI), Hazard Index (HI), Hazard Quotient (HQ), Carcinogenic Health Effect (Cr) and Ingestion Cancer Slope Factors. Gamma Ray Spectrometer was used to profile 238U, 232Th, and 40K levels in the samples. Activity Concentrations, Radium equivalent activity concentration index (Raeq), Absorbed Gamma Dose Rate (ADR), External Hazard Index (Hex), Internal Hazard Index (Hin), Excess Lifetime Cancer Risk (ELCR) and Annual Effective Dose Equivalent (AEDE) were subsequently evaluated.
Open Access
Assessment of levels of radiocavity and potentily toxic elements pulverizd plantain (Musa Paradisiaca L ) obtained from osun east sentorial destrict, Nigeria
(Institute of ecology and envirinmental studies, faculty of science, OAU, 2022) ABE, Toluwase Patience
This study assessed the concentrations of potentially toxic elements in the locally produced plantain flour. It also determined the radioactivity levels in the locally produced flour and assessed the human health risk associated with the contaminants. These were with a view to providing information on the concentrations and health risks of the potentially toxic elements and radionuclides in locally produced plantain flour in the study area.
Open Access
Assessment of polyethylene Terephthalate Waste Carbon and periwinkle Shells-based Chitosan as Adsorbent for Trichloroacetic Acid Removal from Water
(Department of Institute of Ecology and environmental Studies, Faculty of Science, Obafemi Awolowo University., 2022) BABASANMI, Oluwole Abioye
The study determined the physicochemical parameters and trichloroacetic acid concentrations of the water samples before and after conventional treatment at the Obafemi Awolowo University, Ile-Ife water treatment plant. It also investigated the adsorption efficiencies of chitosan modified and unmodified adsorbent prepared from polyethylene terephthalate waste and periwinkle shells for the removal of trichloroacetic acids in the water samples. The study further compared the adsorption efficiencies of commercially available activated carbon with the chitosan modified and unmodified adsorbents. These were with a view to providing information on the adsorption efficiencies of polyethylene terephthalate waste carbon and periwinkle shells-based chitosan with commercially available activated carbon for the removal of trichloroacetic acid from water. Polyethylene terephthalate was obtained from the Obafemi Awolowo University Campus, while the periwinkle shell utilized for chitosan extraction was obtained from the Eket Main Market in AkwaIbom State. Caustic alkali produced from cocoa pod husk was used to activate the PET. The activated carbon was made by carbonizing the caustic alkali impregnated Polyethylene Terephthalate (PET) in a furnace at 500 °C for 1 hour. For elemental and surface morphology determinations, the activated carbon was evaluated using Energy Dispersive X-ray (EDX) and Scanning Electron Microscope (SEM). The Fourier Transform-Infrared (FT-IR) spectroscopic technique was used to determine the structural chemical functional groups in activated carbon. Chitosan was made by deproteinizing, demineralizing, decolourizing, and deacetylating the periwinkle shell. Using a UVvis Spectrophotometer, the level of trichloroacetic acid (TCA) in water samples was detected at 530 nm. Batch adsorption tests were conducted to investigate the removal of TCA under a variety of conditions, including the effect of concentration, adsorbent dosage, pH, and agitation time. Adsorption isotherms were calculated using experimental data from various initial TCA xxii concentrations. The adsorption kinetics were also used to identify a potential rate-limiting phase during the adsorption process. The results showed that the TCA levels were 0.9900 mg/L in raw water and 2.8900 mg/L in conventionally treated water. The PETAC, PETMAC, and commercial activated carbon (CAC) gave mean TCA concentrations of 0.1900±0.0000, 0.0900±0.0000 and 0.0900±0.0000 mg/L before adsorption and 0.1400±0.0707, 0.0900±0.0000 and 0.0000±0.0000 mg/L after adsorption on raw water and conventionally treated water, respectively. There was significant (p < 0.05) difference when raw and conventional treated water were subjected to the three adsorbents. The TCA removed by the two adsorbents (PETAC and PETMAC) required 4 minutes, 1.2 g/L adsorbent dose, and a pH of 9. At 4 minutes of contact time, the highest adsorption efficiencies were 80.286 and 98.286% for PETAC and PETMAC, respectively. The reusability efficiencies of PETAC and PETMAC were 78.4 and 82.4%, respectively. The PETAC with R2 = 0.9377, showed that Langmuir model best fit the TCA adsorption in the isotherm models. The PETMAC with R2 = 0.9986 indicated that the pseudo-second order fitted the kinetic data. This study concluded that activated PET carbon was effective to remove TCA from water supply and could be improved by adding chitosan.
Open Access
Assessment of vehicular emission contributions to ambient air quality along high and low density traffic routes in Lagos and Ile-Ife, southwestern Nigeria.
(Department of Chemistry, Faculty of Science. Obafemi Awolowo University., 2021) JOSHUA, Oluwasesan Hezekiah
The study characterized air emissions from vehicles in Lagos and Ile-Ife, determined theground-level concentrations of associated pollutants along with the ambient air quality levels of selected air pollutants and evaluated the vehicular emissions using the results obtained above. These were with a view to assessing the vehicular emission contributions to ambient air quality along low- and high-density routes in Ile-Ife and Lagos. Four sampling points were established during dry and wet season periods over an averaging period of 24-hour, while traffic count, meteorology, and ambient measurements were carried out simultaneously at each of the sampling points. The vehicle emission measurement which is one of the inputs for predicting ground level concentrations using the BREEZE ROAD Model was carried out using Infra-Red gas analysers for CO, NO2, and SO2 concentrations and handheld aerosol real-time particulate matter (PM2.5) sampler for PM2.5 concentration. Ambient PM2.5 concentrations were measured using Air metric particulate matter sampler, while ambient gaseous concentrations of CO, NO2, SO2, O3, and volatile organic compounds (VOC) were measured using CO data logger, Ogawa sampler, and 3 M air monitor badge. The samples collected using the Ogawa sampler and 3 M air monitor badge were analysed using Gas Chromatography Flame Ionization Detector. The measured ambient mean PM2.5 concentration in Lagos was 152.58± 61.65 µg/m3 while that of Ile-Ife was 93.13±2.24 µg/m3. The measured concentrations of NO2 in Lagos ranged from 21.98 to 64.95 µg/m3and that for Ile-Ife ranged from 10.00 to 55.04 µg/m3. Sulphur dioxide concentration ranged from 20.56 to 58.09 µg/m3 in Lagos and 16.35 to 60.69 µg/m3 in Ile Ife. Carbon monoxide concentrations in Ile-Ife sampling points ranged from 1,030.68 to 3,000.42 µg/m3 while that of Lagos sampling points ranged from 1,030.68 to 3,664.64 µg/m3.Comparative high average level (40.02± 8.5 µg/m3) of VOC was recorded in Lagos than Ile-Ife with an average value of 17.33± 5.46 µg/m3. However, all ambient pollutant values were below Federal Ministry of Environment (FMEnv) and World Health Organization (WHO) limits except PM2.5 and SO2. The predicted mean ground level vehicular concentrations of PM2.5, NO2, SO2, and CO for Lagos were 117.00 ± 25.46, 33.87 ± 5.32, 16.78 ± 13 and 1885.7 ± 565.69 µg/m3respectively while that of Ile-Ife were 86.50 ± 3.54, 13.17 ± 7.98, 15.61 ± 10.97 and 1028.60 ± 969.73 µg/m3respectively. Generally, the average percentile contribution of major vehicle criteria pollutants on the airshed along low and high-density traffic routes were 31 and 42% respectively. The study concluded that the pollutant concentration values obtained, apart from those of PM2.5 and SO2 which were below FMEnv and WHO limits, could cause adverse health by those having regular impacts of the parameters investigated.
Open Access
Assesssment of the effectiveness of lead removal from helianthus annuus L. remediated soil using amaranthus hybridusL .
(The Institute Of Ecology And Environmental Studies, Faculty Of Sciences, Obafemi Awolowo University., 2023) AREGBESOLA Joshua Akin
This study determined the Physical and chemical properties of a Pb remediated soil and assessed the growth response of Amaranthus hybridus cultivated on this soil. It also determined the nutrients and Pb uptake by A. hybridus from the remediated soil. These were with a view to providing information on the effectiveness of Pb removal by Helianthus annuus from a Pb polluted soil. The study was carried out in the screenhouse of the Faculty of Pharmacy, Obafemi Awolowo University (OAU), Ile-Ife. The study was a follow-up on a previous study in which the topsoil was polluted to four levels of Lead concentrations. A total of 72 polythene bags, each containing 10 kilograms of Pb remediated soil obtained after this study showed the presence of Pb. The polythene pots had also received three rates of organic fertilizer; 0, 5 and 10 t ha-1, and two rates; 0 and 2 t ha-1 of Urea fertilizer, and four levels of Pb: 0, 400, 800, 1200 mg Pb kg-1 arranged in a complete randomized design. The seeds of A. hybridus earlier obtained from the Faculty of Agriculture, OAU, Ile-Ife were sown at six seeds per pot, and thereafter watered with distilled water to field moisture capacity. Growth parameters such as number of leaves, plant height and stem girths were collected at 3, 4, 5 and 6 weeks after sowing (WAS) using standard methods, and thereafter terminated. The harvested aboveground biomass of the plant was weighed and oven-dried to constant weight. The pre- and post-cropped remediated soils, and dried plant samples were analyzed to determine their properties, including Pb and Zn using standard methods. Data collected were subjected to descriptive and inferential statistics and the significance in their mean values of growth parameters and soil properties were separated at 95% confidence limit using Tukey‘s Multiple Range Test. The pH of the pre-cropped remediated soil ranged from 5.57 ± 0.02 to 7.43 ± 0.04. The soil organic Carbon and total Nitrogen values ranged from 3.90 ± 0.20 to 33.90 ± 0.30, and 0.30 ± 0.10 to 2.90 ± 0.10 g kg-1, respectively. The initial concentrations of Pb and Zn ranged; 75.16 ± 0.02 to 170.50 ± 8.04 and 3.81 ± 0.02 to 9.54 ± 0.03 mg kg-1, respectively. At harvest, the stem girth of A. hybridus ranged from 0.39 ± 0.06 to 2.81 ± 0.55 cm, while the aboveground biomass yield ranged from 0.11 ± 0.06 to 36.41 ± 9.47 and 0.06 ± 0.03 to 3.70 ± 1.28 g pot-1 for the wet and dry weight, respectively from the pot without Pb contamination, but with 2 t ha-1 of Urea and 5 t ha-1 of organic fertilizer. These growth parameters were significantly (p < 0.05) higher than the values obtained during the repeat experiment. The highest values obtained for Pb and Zn concentrations in the shoots of A. hybridus were 0.50 ± 0.01 and 3.05 ± 0.05 mg kg-1, respectively; which were higher than WHO/FAO permissible limits of 0.005 and 0.60 mg kg-1 for Pb and Zn respectively. The study concluded that Amaranthus hybridus cultivated on Lead remediated soil removed and transported Lead to aboveground biomass of the plant which could eventually enter into the food chain of humans, if ingested.
Open Access
Bioaccumulation and oxidative stress impact of toxic heavy metals and polycyclic aromatic hydrocarbons on selected mosses in Nigeria
(Department of Botany, Faculty of Science, Obafemi Awolowo University., 2023) Olasoji, Kehide Olayemi
This study investigated the bioaccumulation of heavy metals and polycyclic aromatic hydrocarbons in Philonotis hastata (Duby) Wijk & Margad and Barbula lambarenensis P. de la Varde, and also determined the impact of oxidative stress on chlorophyll content and anatomical features of the mosses. These were with a view to providing detailed information on the bioaccumulation potential of the selected mosses as well as the antioxidant response of these mosses to oxidative stress. The moss species were collected in industrial areas in Ile-Ife, Ibadan and Ikeja while the control samples were collected at Obafemi Awolowo University, Ile-Ife. The concentrations of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in moss samples were determined using standard method. Estimation of chlorophyll content (chlorophyll a, chlorophyll b and total chlorophyll) were determined using standard procedure. Stress biomarkers (hydrogen peroxide (H2O2) and proline contents), non enzymatic antioxidant activity (ascorbate, total glutathione, lipid peroxidation and carotenoids) and enzymatic antioxidant activity (superoxide dismutase, catalase and ascorbate peroxidase) were determined following standard procedures. General anatomical features of the stem and leaves of the mosses were studied and photomicrographs of the slides were taken. Data were analyzed using one-way Analysis of Variance (ANOVA) and Duncan Multiple Range Test (DMRT) were used for separation of mean using SAS software, 2001. The concentrations of heavy metals in moss samples in the study locations ranged from: Cu (1.200 – 2.330 µg/g), Zn (0.855 – 1.370 µg/g), Fe (0.525 – 1.050 µg/g), Mn (0.027 – 0.052 µg/g), Cr (0.016 – 0.057 µg/g), Cd (0.018 – 0.045 µg/g), Pb (0.007 – 0.020 µg/g), As (0.010 – 0.018 µg/g). The results revealed that the heavy metal concentrations in the studied moss samples followed the trend: Cu>Zn>Fe>Mn>Cr>Cd>Pb>As. The study showed that copper, zinc and iron were the most accumulated heavy metals while lead and arsenic were the least accumulated heavy metals in all the sampling locations. Moss samples from control sites have the lowest concentration of metals in all the sampling locations. There is significant difference in the accumulation of heavy metals in the mosses with respect to the different locations in the study area. The concentrations of 19 PAHs varied from 0.02 to 3.81 mg/L in P. hastata and from 0.02 to 5.92 mg/L in B. lambarenensis in all the locations. The PAHs were not detected in the moss samples from control sites. Naphthalene and 3-methylcholanthrene were detected in all the study areas except for control sites. There was a significant decrease in chlorophyll a, chlorophyll b and total chlorophyll contents of the selected mosses when compared to chlorophyll contents of mosses from control sites. The selected mosses exhibited significant variations in the antioxidant response to oxidative stress in polluted sites and control sites. The anatomical studies of the stem and leaves of the selected mosses showed there is no feasible effect of pollutants bioaccumulation on micromorphological features of the moss species obtained from polluted sites when compared to moss species from the control sites. The study concluded that accumulation of heavy metals and polycyclic aromatic hydrocarbons in the selected mosses from industrial areas induces oxidative stress and causes reduction in their chlorophyll contents. The antioxidant response of these mosses indicated that the selected moss species were tolerant to oxidative stress.
Open Access
Bioaccumulation and Oxidatives stress impact of toxic heavy metala and polycyclic aromatic hydrocarbons on selected mosses in Nigeria
(Department of Botany, Faculty of Science, Obafemi Awolowo University., 2023) OLASOJI Kehinde Olayemi
This study investigated the bioaccumulation of heavy metals and polycyclic aromatic hydrocarbons in Philonotis hastata (Duby) Wijk & Margad and Barbula lambarenensis P. de la Varde, and also determined the impact of oxidative stress on chlorophyll content and anatomical features of the mosses. These were with a view to providing detailed information on the bioaccumulation potential of the selected mosses as well as the antioxidant response of these mosses to oxidative stress. The moss species were collected in industrial areas in Ile-Ife, Ibadan and Ikeja while the control samples were collected at Obafemi Awolowo University, Ile-Ife. The concentrations of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in moss samples were determined using standard method. Estimation of chlorophyll content (chlorophyll a, chlorophyll b and total chlorophyll) were determined using standard procedure. Stress biomarkers (hydrogen peroxide (H2O2) and proline contents), nonenzymatic antioxidant activity (ascorbate, total glutathione, lipid peroxidation and carotenoids) and enzymatic antioxidant activity (superoxide dismutase, catalase and ascorbate peroxidase) were determined following standard procedures. General anatomical features of the stem and leaves of the mosses were studied and photomicrographs of the slides were taken. Data were analyzed using one-way Analysis of Variance (ANOVA) and Duncan Multiple Range Test (DMRT) were used for separation of mean using SAS software, 2001. The concentrations of heavy metals in moss samples in the study locations ranged from: Cu (1.200 – 2.330 μg/g), Zn (0.855 – 1.370 μg/g), Fe (0.525 – 1.050 μg/g), Mn (0.027 – 0.052 μg/g), Cr (0.016 – 0.057 μg/g), Cd (0.018 – 0.045 μg/g), Pb (0.007 – 0.020μg/g), As (0.010 – 0.018 μg/g). The results revealed that the heavy metal concentrations in the studied moss samples followed the trend: Cu>Zn>Fe>Mn>Cr>Cd>Pb>As. The study showed that copper, zinc and iron were the most accumulated heavy metals while lead and arsenic were the least accumulated heavy metals in all the sampling locations. Moss samples from control sites have the lowest concentration of metals in all the sampling locations. There is significant difference in the accumulation of heavy metals in the mosses with respect to the different locations in the study area. The concentrations of 19 PAHs varied from 0.02 to 3.81 mg/L in P. hastata and from 0.02 to 5.92 mg/L in B. lambarenensis in all the locations. The PAHs were not detected in the moss samples from control sites. Naphthalene and 3-methylcholanthrene were detected in all the study areas except for control sites. There was a significant decrease in chlorophyll a, chlorophyll b and total chlorophyll contents of the selected mosses when compared to chlorophyll contents of mosses from control sites. The selected mosses exhibited significant variations in the antioxidant response to oxidative stress in polluted sites and control sites. The anatomical studies of the stem and leaves of the selected mosses showed there is no feasible effect of pollutants bioaccumulation on micromorphological features of the moss species obtained from polluted sites when compared to moss species from the control sites. The study concluded that accumulation of heavy metals and polycyclic aromatic hydrocarbons in the selected mosses from industrial areas induces oxidative stress and causes reduction in their chlorophyll contents. The antioxidant response of these mosses indicated that the selected moss species were tolerant to oxidative stress.

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