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Ibadan, Nigeria

Adeogun A.O.,University of Ibadan | Ibor O.R.,University of Ibadan | Omogbemi E.D.,University of Ibadan | Chukwuka A.V.,University of Ibadan | And 3 more authors.
Marine Environmental Research | Year: 2015

The high global occurrence of phthalates in different environmental matrixes has resulted in the detection of their metabolites in human urine, blood, and breast milk, indicating a widespread human exposure. In addition, the notorious endocrine disrupting effects of phthalates have shown that they mimic or antagonize the action of endogenous hormones, consequently producing adverse effects on reproduction, growth and development. Herein, we have studied the occurrence of phthalate esters (PEs) in water, sediment and biota of two lagoons (Epe and Lagos) in Nigeria. Two fish species (Tilapia guineensis, and Chrysichthys nigrodigitatus) and a crustacean (the African river prawn - Macrobrachium vollenhovenii) were analyzed for PEs levels using a HPLC method and the derived values were used for calculating bioconcentration factor (BCF), biota-sediment accumulation factor (BSAF) and phthalate pollution index (PPI) in the biota and environment. We observed that the growth and health condition of the fish species were normal with a k-factor of >1. Sediment PE levels were compared with water, at both lagoons showing concentration pattern that is characterized as DEHP=DEP>DBP. We observed that DBP was the predominant compound in T.guineensis, C.nigrodigitatus and African prawn, at both lagoons, showing organ-specific differences in bioconcentration (BCF and BSAF) patterns in the fish species. While there were no observed consistency in the pattern of PE concentration in fish organs, elevated DBP levels in different fish organs may be related to fish habitat and degradation level of phthalates. Low concentration of DEHP, compared with DBP and DEP, was measured in fish organs and whole prawn body. The BSAF values for DEHP were lowest, and highest for DBP for all species at both lagoons, and DEHP easily accumulated more in the sediment (sediment PPI=0.28 and 0.16 for Epe and Lagos lagoon, respectively). Overall, our findings suggest a broader environmental and human health implication of the high PE levels in these lagoons since they represent significant sources of aquatic food resources for the neighboring communities. © 2015 Elsevier Ltd.

Olaniran O.,Tshwane University of Technology | Olaniran O.,Federal University of Technology Akurre | Adewuyi B.O.,Tshwane University of Technology | Omotoyinbo J.A.,Tshwane University of Technology | And 4 more authors.
Leonardo Electronic Journal of Practices and Technologies | Year: 2015

Duplex stainless steels have a wide range of engineering applications, mainly in automotive, energy, chemical, mining as well as medical industries. The need for advanced researches to improve on the properties is therefore, very important and urgent. This work aims at developing composites of duplex stainless steel by oxide dispersion strengthening method using hot press sintering technique. Powder of ceramic oxide (partially stabilized Zirconia PSZ, 3% yttria, mole fraction) were dispersed in 2205 duplex stainless steel powders. The ceramic oxide (PSZ) was added as reinforcement, while chromium (Cr) and Nickel (Ni) were incorporated to maintain the austenitic/ferritic phase balance of the duplex stainless steel. The powders and sintered were characterized in detail using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The microstructural evolution and phase formation during oxide dispersion strengthening of duplex stainless steels composites were investigated. The influences of composition variation of the reinforcements on the microstructural and corrosion behavior of the composites in simulated mine water were investigated. In this work, it was established that composition has great influence on the structure/properties relationship of the developed composites. © 2015, AcademicDirect. All rights reserved.

Adesokan I.A.,UK Defence Science and Technology Laboratory | Ekanola Y.A.,The Polytechnic | Okanlawon B.M.,Ladoke Akintola University of Technology
African Journal of Microbiology Research | Year: 2010

In this study, influence of cultural conditions on hydrogen peroxide production by lactic acid bacteria was investigated. Leuconostoc mesenteroides produced the highest quantity (0.024 L) of hydrogen peroxide while Lactobacillus plantarum produced the lowest amount (0.016 g/L) in normal MRS. The effect of temperature on hydrogen peroxide production was determined and the result showed that Leuc. mesenteroides produced the highest quantity (0.024 g/L) at 30°C while L. brevis produced the lowest amount (0.012 g/L) of hydrogen peroxide at 45°C. Leuc. mesenteroides produced the highest amount of hydrogen peroxide (0.032 g/L) when mannitol was used as the carbon source while Lactobacillus delbrueckii and Lactobacillus fermentum produced the lowest amount (0.020 g/L) when glucose was used as the carbon source. Furthermore, Leuc. mesenteroides produced the highest amount of hydrogen peroxide (0.033 g/L) when potassium nitrate was used as the nitrogen source while L. fermentum and L. delbrueckii produced the lowest amount (0.020 g/L) when yeast extract was used as the nitrogen source. Hydrogen peroxide produced by Leuc. mesenteroides has the highest zone of inhibition against Pseudomonas aeruginosa while hydrogen peroxide produced by L. plantarum had the lowest zone of inhibition against Staphylococcus aureus. © 2010 Academic Journals.

Oluwafemi F.,Abeokuta Federal University of Agriculture | Badmos A.O.,Abeokuta Federal University of Agriculture | Badmos A.O.,National Agency for Food | Kareem S.O.,Abeokuta Federal University of Agriculture | And 2 more authors.
Mycotoxin Research | Year: 2014

Aflatoxin M1 (AFM1) in milk from 100 different herds of free-grazing cows in Abeokuta, Nigeria, was analysed by immunoaffinity column cleanup and HPLC with fluorescence detection. AFM1was found in 75 % of the samples, the toxin levels in positive samples ranged from 9.0 to 456.0 ng/l. The mean AFM1level in positive samples was 108.15 ng/l, exceeding, for example, the European Union maximum level by a factor of two. These results indicated that there is an urgent need to more closely control the milk of free-grazing cows for AFM1in order to protect the health of humans consuming milk and milk products. © 2014, Society for Mycotoxin Research and Springer-Verlag Berlin Heidelberg.

Oyero O.G.,The Polytechnic | Oyefolu A.B.,Lagos State University
Pan African Medical Journal | Year: 2010

Introduction: In recent times, food safety and security have generally remained basic human needs, therefore because of the largely unregulated nature of the Nigerian markets, coupled with the poor housing and feeding conditions to which animals are subjected in the abattoirs, a survey for assessing potential mycotoxin exposure through meat consumption was undertaken. Methods: Eighty Samples of meat bought randomly from 5 major markets distributed in 5 local government areas of Oyo state, Nigeria were analysed for contaminating mycoflora using the plate count and micromorphological methods, while aflatoxin detection and quantification was by Thin Layer Chromatography (TLC). Results: Mycological analysis of samples revealed a higher contamination level in the sun-dried samples. Eighteen fungi species belonging to 8 genera, namely, Aspergillus, Penicilliu, Alternaria, Cladosporium, Fusarium, Neurospora, Rhizopus and yeast were identified. The predominant genus Aspergillus yielded 7 species while the potential toxicogenic fungi represented 38% of the isolated mycoflora. The genera requiring higher water activity for growth (Alternaria, Fusarium and yeast) were not obtained from the dried meat. Aflatoxins B1, B2, G1 and G2 were detected in all the samples analysed. The fresh samples with the exception of the total aflatoxin G (AFG) in kidney gave the highest mean concentrations for all aflatoxins, also an exceptionally high aflatoxin content was found in all the kidney samples. Conclusion: Aflatoxin detection in meat should be addressed urgently to avert the possible adverse health effects like aflatoxicosis, exacerbated malnutrition, suppression of growth and immune functions on consumers. Also the animal health inspectors should pay more attention to the feeding conditions of the animals on farm and the abattoirs.

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