Department Of Chemistry

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Browsing Department Of Chemistry by Author "Adebowale, K.O."

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    Open Access
    Chromolaena odorata, soil, waste disposal, contamination factor, metals pollution
    (2008) Agunbiade, F.O.; Olu-owolabi, B.I.; Adebowale, K.O.
    The ability of Chromolaena odorata to accumulate and serve as biomarker to lead and cadmium metals pollution load had been revealed by this study. Samples of soils and Siam weed were collected to assess impacts of solid waste disposal and traffic density on the environment. Composite sample were collected from a solid waste dumpsite, three traffic polluted areas with varying traffic density and a background site distant from traffic. Concentration of eight elements: cadmium, cobalt, chromium, copper, iron, nickel, lead and zinc were determined in soil and plant samples and correlated together. Accumulative factors like pollution load index, transfer factor, contamination factor, enrichment factor were calculated for the metals in both plants and soils and used as basis for interpreting the state of the environment and ability of C. odorata to accumulate metals. The accumulative factors of plants were generally greater than that of soil samples indicating increased accumulative capacity of the plant. The accumulations of lead and cadmium in C. odorata were remarkable with contamination factor 10.51 and 23.50, respectively and mean enrichment factors 3.52 and 6.93, respectively. Other metals had lower accumulative factors. The distribution of metals and calculated factors placed solid waste disposal site as the most polluted site while the trend observed in areas with traffic pollution depicts the ability of C. odorata to clean up metal pollution by accumulating them. It can therefore be suggested that solid waste disposal negatively affects the environment more than traffic pollution subject to the volume of traffic.
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    Open Access
    Comparative Assessment of Coastal Water Usage Supports Using Water Quality Indices and Fuzzy Synthetic Evaluation Methods: Ondo Estuary Case Study, Nigeria.
    (Terrestrial and Aquatic Environmental Toxicology, 2012) Agunbiade, F.O.; Olu-owolabi, B.I.; Adebowale, K.O.
    The ability of water quality indices and fuzzy synthetic evaluation methods to combine large and technical water quality data into a single value that could help understand and communicate the status of water bodies and their usage supports for policy formulation is revealed by this study. Three water quality indices and two fuzzy synthetic evaluation methods were used to assess the usage support of Ondo estuarine water and the results compared. The indices revealed that the sites distant to the estuarine discharge point improved in quality and support uses than the ones nearer. Desalination of such will further improve is usage support. Anthropogenic activities are negatively affecting the quality of the environment and need to be managed if good quality water will be made available for economic uses and the vast aquatic life resources in the estuary and the neighbouring Atlantic Ocean will not be adversely affected.
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    Open Access
    Empirical Modelling of Dissolved Oxygen against Pollution Parameters in Coastal Water in Different Seasons
    (Global Science Books, 2008) Agunbiade, F.O.; Olu-owolabi, B.I.; Adebowale, K.O.
    An empirical modelling study of dissolved oxygen (DO) against six pollution parameters: biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrate, total phosphate, total solids and temperature, analysed from field samples was carried out for wet and dry seasons of April 2006 – January 2007. Modelled equations were developed from each parameter using regression analysis to predict DO within the two seasons; the best fitted equation was reported in each case with their corresponding R2 values and the validity ranges evaluated for model calibration. The resulting DO values predicted from the modelled equations were validated by comparison with field data and found to correlate better in the dry season for data obtained based on BOD, COD, nitrate and phosphate. Also, the validity ranges of the models developed from these anthropogenic pollution parameters were wider during the dry season. However, total solids (TS) and temperature used to measure contributions from physical and natural conditions to DO modelling depicts a better simulation during the wet season for the TS prediction due to an increase in natural effects witnessed in the wet season than the dry one. Temperature had the lowest R2 values due to reduced natural temperature variations in the tropical region. Thus, the predictions of DO based on anthropogenic, abstracting pollution parameters are better done in the dry season.Keywords: anthropogenic activities, regression analysis, simulation, wet and dry seasons
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    Open Access
    Fate and Mobility of Copper in Soil of Cocoa Plantations in two South-Western States of Nigeria treated with Copper-Based Fungicides. Soil and Sediment Contamination
    (Taylor and Francis, 2012) Olu-owolabi, B.I.; Agunbiade, F.O.; Adebowale, K.O.; Ogunleye, I.O.
    Soils from cocoa plantations treated with Boudreaux mixture in two southwestern states of Nigeria were collected at different depths, 0–15 cm and 15–30 cm, and subjected to five-stage sequential extraction to obtain the speciation forms of copper: exchangeable, carbonate, manganese and iron oxides, organic and residual fractions. The Cu content in the extracts from the sequential extraction was read with an Atomic Absorption Spectrophotometer (AAS). The total Cu content of the soil and the physicochemical parameters of the soils were also determined. The results from the study showed that the soils had high organic matter and copper is mostly bounded to the more mobile exogenic phase much more than the stable lithogenic phase, indicating higher mobility. Within the exogenic species, carbonate fraction was the highest followed by the organic bound and the exchangeable fraction in decreasing order. Cu was not detected in the Fe/Mn bound fraction. The implication is that the fate of the administered Cu-based pesticide is more in the relatively stable carbonate bound species than the other, more mobile phase. The results showed variation in the distribution of the copper species from one depth to another. The most transported metal from the surface to the lower layer is the exchangeable fraction. The carbonate bound species is less mobile and is not readily transported into the bottom soil layer. The organic bound Cu has nearly equal distribution between the top and bottom soils and there was little or no transport of the residual metal specie from the top to the bottom. The existence of copper in the soil largely in the anthropogenic (exogenous) phase is not the most desirable for the ecosystem. This may increase the availability of Cu in the cocoa plant and bean and may lead to potential exposure risk.
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    Open Access
    Fuzzy comprehensive assessment of metal contamination of water and sediments in Ondo Estuary, Nigeria
    (Taylor and Francis, 2008) Adebowale, K.O.; Agunbiade, F.O.; Olu-owolabi, B.I.
    A more reliable methodology for evaluating metal contamination of coastal water and sediments using fuzzy comprehensive assessment (FCA) is presented by this study. Ten metals (As, Cd, Cu, Cr, Fe, Mn, Ni, Pb, V and Zn) were investigated in water and sediments from ten sampling sites and formulated into fuzzy matrix based on three contamination classifications of pristine, moderately enriched and extremely impacted categories using regulatory limits as criteria. The products of the matrices from membership function of the observed data and the weight matrices generate indices that classify the degree of metal impact on the sites. The results of the FCA show that the estuary is negatively impacted by metals in a range of 45.5–75.1% membership in the extremely impacted category with potential adverse effects on the ecosystem of the neighbouring Atlantic Ocean. The crude oil exploration activity at site 1 is the major source input of the metals beside Fe and Mn which are natural to the geological structure of the area while domestic waste discharges contribute notably to metal contamination in some sites.
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    Open Access
    Fuzzy logic modeling of bioaccumulation pattern of metals in coastal biota of Ondo State, Nigeria
    (2012) Agunbiade, F.O.; Olu-owolabi, B.I.; Adebowale, K.O.
    The accumulation patterns of ten metals in tissues of plant, Eichornia crassipes, and fishes, Hydrocynus forskahlii and Oreochromis mossambicus, were modeled with simple fuzzy classification (SFC) to assess toxic effects of anthropogenic activities on the coastal biota. The plant sample was separated into root, stem, and leaves and the fishes into bones, internal tissues, and muscles. They were analyzed for As,Cd, Cr, Cu, Ni, Pb, V, Fe, Mn, and Zn after wet oxidation of their dried samples. The results were converted into membership functions of five accumulation classes and aggregated with SFC. The classification results showed that there was no metal accumulation in the plant parts while the fishes were classified into low accumulation category. The internal tissues of the fishes had higher metal accumulation than the other parts. Generally, Fe and Mn had highest concentrations in the biota but are natural to the area and may not constitute significant risk. Cr had the highest transfer and accumulation from the coastal water into the aquatic lives and may be indicative of risk prone system being a toxic metal. Metal contaminations in the zone had not significantly accumulated in the biota making them less prone to risk associated with metal accumulation.
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    Open Access
    Fuzzy logic modeling of bioaccumulation pattern of metals in coastal biota of Ondo State, Nigeria
    (Springer, 2012) Agunbiade, F.O.; Olu-owolabi, B.I.; Adebowale, K.O.
    A more reliable methodology for evaluating metal contamination of coastal water and sediments using fuzzy comprehensive assessment (FCA) is presented by this study. Ten metals (As, Cd, Cu, Cr, Fe, Mn, Ni, Pb, V and Zn) were investigated in water and sediments from ten sampling sites and formulated into fuzzy matrix based on three contamination classifications of pristine, moderately enriched and extremely impacted categories using regulatory limits as criteria. The products of the matrices from membership function of the observed data and the weight matrices generate indices that classify the degree of metal impact on the sites. The results of the FCA show that the estuary is negatively impacted by metals in a range of 45.5–75.1% membership in the extremely impacted category with potential adverse effects on the ecosystem of the neighbouring Atlantic Ocean. The crude oil exploration activity at site 1 is the major source input of the metals beside Fe and Mn which are natural to the geological structure of the area while vdomestic waste discharges contribute notably to metal contamination in some sites.
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    Open Access
    Fuzzy Logic Modeling of Contamination Degree of Ni and V Metal Species in Sediments from the Crude Oil Prospecting Area of the Ondo Coast, Nigeria
    (Taylor and Francis, 2012) Olu-owolabi, B.I.; Agunbiade, F.O.; Osegbe, E.O.; Adebowale, K.O.
    There are numerous statistical models for evaluating the degree of pollution in an environment. This study presents a fuzzy logic–based model—simple fuzzy classification (SFC)—for evaluating contamination of Ni and V species in the sediments of Nigeria’s Ondo coastal area. Concentrations of five species of these metals were obtained from 10 sampling sites following sequential extractions from sediments. The results were formulated into a fuzzy membership function matrix based on three classifications relative to regulatory standards and sediments’ degree of contamination. The results of the SFC show that the estuary is moderately enriched by Ni species in a range of 61–84% and further introduction of Ni may shift its contamination level into the highly polluted category. The SFC results also show that the estuary is clean of V species contamination in a range of 77–99%. The Ni and V were associated with the organic specie notably at the crude oil exploration site and at the coastal discharge point. Crude oil exploration and domestic wastes discharges are notable sources of metal contaminations into the estuary. However, the salinity incursion from the coastal ocean and prevailing biogeochemistry affect the species in which the metals exist.
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    Open Access
    Fuzzy logic-based modeling of the impact of industrial activities on the environmental status of an industrial estate in Nigeria
    (Taylor and Francis, 2011-12) Agunbiade, F.O.; Awe, A.A.; Adebowale, K.O.
    Industrial growth is being attributed with adverse environmental effects and has necessitated stricter environmental management policies. Formulating such policies is limited by the difficulty in understanding the trends of monitoring data. This study is aimed at the application of fuzzy comprehensive assessment (FCA) to integrate environmental contaminants in Agbara industrial estate, Nigeria, to measure the extent of impact of industrial activities on the host community. Samples of water, plants (Pteridium aquilinum, Sacciolepis africana, and Panicum maximum), soil, and sediments were collected within the estate. Water samples were analyzed for quality parameters using standard methods. Metals (Co, Cr, Cd, Cu, and Mn) were investigated in all the samples using an atomic absorption spectrophotometer. The data were modeled with FCA. The results showed Cr as the major contaminant (34–252 mgL1 ). High phosphate contributed to large plant growth in the area. FCA results showed that water samples were in the pristine classification; sediment samples were extremely impacted. The vegetation growth and the sediment precipitation were responsible for the cleaning-up of the pollutants discharged downstream. The FCA of the plants indicated high metal bioaccumulation and not only showed the plants’ phyto-remediation potential but also that the metals may pose threats to human health through the food web. The activities in the estate are contributing contaminants to the environment with potential negative effects.
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    Open Access
    Impacts of natural and anthropogenic multiple sources of pollution on the environmental conditions of Ondo State coastal water, Nigeria
    (Electronic Journal of Agricultural and Food Chemistry, 2008) Adebowale, K.O.; Agunbiade, F.O.; Olu-owolabi, B.I.
    The pollution status of the coastal water of Ondo State, Nigeria was investigated and found to be stressed by pollutants from both anthropogenic and natural sources. Solids (total solids, total dissolved solids, and total suspended solids), alkalinity, hardness, dissolved oxygen (DO), biochemical and chemical oxygen demand were evaluated as measures of environmental pollution of the area. Also, some ionic and metal components were analysed. Principal component analysis and linear correlation model of the data revealed that the coastal water was negatively impacted by pollutants from related anthropogenic sources and natural sources and that atmospheric precipitation and tidal activities ensure the perfect mix of the pollutants across the site. Seawater intrusion and erosion of the soil into the coastal water are natural activities stressing the water that it may not support uses. The observed DO of the water system was high (mean value – 7.85mgO2/L) due to tidal agitation while the BOD also were lower than 3mgO2/L in most sites. However, the concentrations of chloride and sulphate in the water system were on the high side ranging from 13,074– 17,366mg/L and 2,119 – 3,143mg/L respectively. The metal components investigated were beneficial to human health but exist in concentration too high for human consumption. Fe, Mn, Cu, and Zn were found to be anthropogenic metals from related sources in this coastal area having correlated positively and significantly with measures of organic matter and each other. There were also indications of natural contributions of Fe, Mn & Cu from the soil of the coastal area. Therefore, there is a growing need to monitor and control the release of pollutant into the coastal water system of developing countries having been overlooked.
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    Open Access
    Monitoring Cu bioaccumulation in cocoa from Cu-based pesticides treated cocoa farms using Fuzzy Similarity Method
    (Taylor and Francis, 2013) Olu-owolabi, B.I.; Agunbiade, F.O.; Bamidele, O.; Fagbayigbo; Adebowale, K.O.
    Cocoa production has been hindered by pests, leading to application of pesticides. These pesticide applications have raised health concerns. This study is therefore aimed at developing accumulation classifications for copper (Cu) in cocoa from plantations where Cu-based pesticides have been applied using fuzzy similarity method (FSM). Cocoa pods, seeds, leaves, and soil samples were collected from five different plantations from three states in Nigeria. The plant samples were digested using standard methods, whereas the Cu in soil samples was extracted with 1 M ammonium acetate. The products were analyzed for Cu using flame atomic absorption spectrophotometer. The Cu concentrations obtained were used to model the accumulation degree using FSM. The Cu concentrations were higher in the leaves than the seeds and the pods. The persistency of Cu was displayed by high concentrations (11.5–375 mg/kg) and enrichment factor in CRIN sites where this pesticide application has been stopped for over a decade. The leaves from Ondo sites had the highest Cu concentration, which indicates impact of recent applications. The FSM membership function and algorithm indicated that the plant parts had low degrees of accumulation for fresh leaves, pods, and seeds, the valued part applied in beverages, but for the dry leaves, the accumulation degree is high. It may be concluded that the applied Cu-based pesticide had more impact and accumulation on the leaves than the commercial valued seeds, but the Cu concentration in the seeds is above the recommended value.
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    Open Access
    Phytoremediation potential of Eichornia crassipes in metal-contaminated coastal water
    (Elsevier, 2009) Agunbiade, F.O.; Olu-owolabi, B.I.; Adebowale, K.O.
    The potential of Eichornia crassipes to serve as a phytoremediation plant in the cleaning up of metals from contaminated coastal areas was evaluated in this study. Ten metals, As, Cd, Cu, Cr, Fe, Mn, Ni, Pb, V and Zn were assessed in water and the plant roots and shoots from the coastal area of Ondo State, Nigeria and the values were used to evaluate the enrichment factor (EF) and translocation factor (TF) in the plant. The critical concentrations of the metals were lower than those specified for hyperaccumulators thus classifying the plant as an accumulator but the EF and TF revealed that the plant accumulated toxic metals such as Cr, Cd, Pb and As both at the root and at the shoot in high degree, which indicates that the plant that forms a large biomass on the water surface and is not fed upon by animals can serve as a plant for both phytoextraction and rhizofiltration in phytoremediation technology.
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    Open Access
    Seasonal and spatial variations analysis of pollution status of Ondo coastal environment Nigeria using principal component analysis
    (Geochemical Journal, 2010) Agunbiade, F.O.; Olu-owolabi, B.I.; Adebowale, K.O.
    The variation in environmental quality of Ondo coast between seasons and sites were evaluated using principal component analysis (PCA). Seventeen metals were analysed in water and sediments with five anionic components further evaluated in water samples. The dry season concentrations of parameter and their degree of variation are higher than that of wet season. PCA of sediments revealed four parameter clusters and five clusters for water based on related sources of input, biogeochemical reactions or effects of physical conditions which are useful means of managing pollution when understood. The concentrations of sediment parameters were higher while their variations are narrower than for water parameters making sediment a veritable tool in coastal pollution monitoring. Mg is the most abundant metal in the sediment while Na and chloride are the most prominent in water. The incursion of saline water therefore plays a major role in the dispersion of pollutants and the water-sediment chemistry of the coast. The spatial variation based on the sediment parameters are much conservative than the water-based. Overall, site 9 and 10 were distinct from the others while sites 1,2, 3 related perfectly playing important roles in the sourcing and chemistry of pollutants in the coast.
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    Open Access
    Speciation of metals in sediments from crude oil prospecting coastal area of Ondo State, Nigeria. Earth Sciences Research Journal
    (Earth Sciences Research Journal, 2013) Olu-owolabi, B.I.; Agunbiade, F.O.; Adebowale, K.O.
    Information obtainable from metal speciation is far more valuable regarding the bioavailability, toxicity and fate of metals than information from total metal data. Metal speciation on sediment was thus carried out in this study to assess the bioavailability, fate and mobility of As, Cd, Cr, Fe, Mn, Ni, Pb, and V in the crude oil prospecting area of Ondo State in Nigeria. Five operationally-defined metal species were obtained using the sequential extraction method: exchangeable species, carbonate-bound species, iron/manganese-bound species, organic-bound species and residual species. Species’ concentration, spread and relative abundance were used to assess their fate, mobility and potential toxicity. The crude oil exploration site and the mouth of the estuary had the highest concentrations of these metals compared to other sites. The exchangeable and the organic-bound high risk species were most predominant in the crude oil exploration sites but their concentration became reduced downstream away from these sites. The residual fraction (the least in the crude oil prospecting site) was the most predominant in the most distant sites downstream. There were indications of self-management of the metals in the coastal system through favourable biogeochemical reactions partitioning metals from high risk species from low risk ones and the non-toxic residual fraction. It could, however, be concluded that sediment from the crude oil prospecting area may serve as non-point sources for metals contaminating the coastal system, they have higher metal bioavailability and higher toxicity risk potential than other sites (which should be curtailed).
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    Open Access
    Trace Metal Concentrations, Site Variations and Partitioning Pattern in Water and Bottom Sediments from Coastal Area: A Case Study of Ondo Coast, Nigeria
    (Medwell journals, 2009) Adebowale, K.O.; Agunbiade, F.O.; Olu-owolabi, B.I.
    The observed trend in the investigation of the fate of trace metals in the water and bottom sediments of the Ondo coastal area revealed how domestic waste disposal, oil exploration and agricultural activities can create potential hazard to the ecosystem. Samples of water and bottom sediments collected and analysed for 12 metals: As, Cd, Cr, Co, Fe, Ni, Mn, Mo, Pb, V, Sn and Zn, showed elevated concentration of these metals in the environment while, the enrichment factors calculated showed Fe as the most enriched metal. There were significant relationship between these metals and organic matter concentration in sediment samples. Site SW01 , SW02 and SW06 had the highest enrichment of metals indicating pollution from anthropogenic sources and trans-boundary movement. The Principal Component Analysis (PCA) showed that Mn and Fe found to be abundant in both water and sediment were clearly from the geological structure of the area with minimal anthropogenic contributions. The partitioning and the Pollution Load Index (PLI) of the metals favour the accumulation of metals in the sediment phase. The observed relationships of the metals with organic carbon caused the association of the metals concentration with the sediment column but increased salinity and storm action are aiding increas ing concentration of bioavailable metals in the water column creating potential hazard for the coast.