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Materials Sciences and Applications 2012年第8期3卷 566-574页

作者： Lami A. Nnamonu rufus sha’ato Ikenna Onyido Department of Chemistry Nnamdi Azikiwe University Awka Nigeria Department of Chemistry University of Agriculture Makurdi Nigeria

In a bid to make slow release formulations of imazaquin, the herbicide was encapsulated in starch and chitosan beads reinforced with alginate. The beads were characterized using SEM, DSC and FTIR. Two types of formulations were made by extrusion into 0.25 M calcium chloride solution: chitosan/alginate (LNCI) and starch/alginate (LNSI) beads, and the third was by gelatinization of starch at 75?C (LNSI2). Findings showed highly porous spherical beads, the starch/alginate beads bigger and less porous than the chitosan/alginate beads with diameters of 2.53 ± 0.01 and 2.31 ± 0.01 mm;porosity of 57.58% ± 0.2% and 81.28% ± 0.2% and swelling of 34.91% ± 0.2% and 80.35% ± 0.2%, respectively. FTIR revealed a reduction in intensity of the carboxylate peaks of alginate and the peak at 1058 cm?1, present in the FTIR of the matrices, is shifted to lower wave-numbers in the formulations, signifying interactions between the formulation components that make for good slow release. The DSC thermograms of all formulations showed evidence of interaction of imazaquin carboxylate group with the N-atoms of the macromolecules, which is indicative of reduced crystallinity of imazaquin.

关键词： Alginate Chitosan Starch Encapsulation Imazaquin

Environmentally Friendly Formulations of Trifluralin Based on Alginate Modified Starch

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Journal of Environmental Protection 2012年第9期3卷 1085-1093页

作者： Ikenna Onyido rufus sha’ato Lami A. Nnamonu Department of Chemistry Nnamdi Azikiwe University Awka Nigeria Department of Chemistry University of Agriculture Makurdi Nigeria

In line with global efforts towards sustainable agriculture, the use of starch modified with alginate in the preparation of slow release formulations of the herbicide trifluralin was investigated. Trifluralin was encapsulated in starch-alginate beads, and the resulting slow release formulations (SRFs) characterized using scanning electron microscopy (SEM) and Fourier Transform infrared (FTIR) spectroscopy. Herbicide release from the SRFs was studied in water and compared to release of technical grade trifluralin. Three sets of formulations were made by extrusion into 0.25 M calcium chloride solution: starch/alginate (SSTRF), amylose starch/alginate (ASSTRF) and amylose starch/alginate/groundnut oil (ASTRGNO) beads, and the fourth was from gelatinized starch at 75?C (SSTRF2). The results showed highly porous spherical beads, the amylose/alginate beads bigger and less porous than the starch/alginate beads with diameters of 2.79 ± 0.01 and 2.37 ± 0.01 mm;porosity of 54.67 ± 0.2 and 60.59% ± 0.2% and swelling of 54.09 ± 0.2 and 61.22% ± 0.2%, respectively. All sets of beads exhibited reduced crystallinity of trifluralin. FTIR revealed a shift to lower wavelength of the carbonyl stretching vibrations from 1750 to 1725 cm–1 and a reduction in intensity of the carboxylate peaks of alginate, suggesting interactions between the formulation components that make for good slow release. 96% of technical grade trifluralin (TGTRF) was released into a 50:50 pH 6.5 Buffer/ Methanol aqueous medium in 24 hrs. However, for the starch/TRF formulation, SSTRF, only 9.33% herbicide was released after 24 hrs and 34.94% after 672 hrs (28 days). The amylose starch/TRF formulation released 13.61% herbicide in 24 hrs and 46.95% in 672 hrs, a 12% increase in release of TRF over the starch formulation. Encapsulation in starch produced 65% slow release of TRF and gelatinization achieved 84% retardation. Use of amylose starch as matrix caused 53.15% delay and addition of groundnut oil resulted in 8

关键词： Alginate Groundnut Oil Starch Slow Release Trifluralin

Analysis of Selenium Content in Root and Tuber Plants in Central Nigeria

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American Journal of Analytical Chemistry 2013年第12期4卷 739-743页

作者： Saidu Zarmai Ishaq S. Eneji rufus sha’ato Department of Chemistry Centre for Agrochemical Technology University of Agriculture Makurdi Nigeria

Some common staple roots and tubers (cassava, yam, sweet potato and yellow yam) were analyzed for selenium content level using hydride generation—atomic absorption spectrophotometry (HG-ASS) technique. Results for duplicate analysis revealed that sweet potato has the highest mean selenium content (19.2 ± 5.20 μg/kg), followed by yellow yam (18.3 ± 6.97 μg/kg), then yam (13.6 ± 7.12 μg/kg) and cassava the least (13.0 ± 5.84 μg/kg). In comparing our results with the literature values, most of the results obtained in this work such as ato be popularized as a staple, much more than cassava as it is now the case in Central Nigeria.

关键词： Selenium Content Roots and Tubers Central Nigeria HG-AAS

Spatial and Temporal Variation in Water Quality of River Benue, Nigeria

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Journal of Environmental Protection 2012年第8期3卷 915-921页

作者： Ishaq S. Eneji Agada P. Onuche rufus sha’ato Department of Chemistry and Centre for Agrochemical Technology University of Agriculture P. M. B. 2373 Makurdi Benue State Nigeria Department of Mathematics/Statistics/ Computer Science University of Agriculture P. M. B. 2373 Makurdi Benue State Nigeria

The study investigates the spatial and temporal variation in water quality parameters at ten different locations along River Benue for twelve consecutive months. In order to explore the spatial variation among different stations and seasonal changes, multivariate analysis of variance (MANOVA) was used to group these on the basis of spatial similarities. MANOVA on season and station shows that there is no significant difference between the stations investigated while there is for the seasons. This could be viewed as a resulting from the narrow spatial sampling interval (12 km at 0.7% total length of River Benue). However, discriminate analysis identified all the parameters to discriminate between the three seasons with 99.2% correct assignations. Two discriminate functions were found and the total variance cumulative was 100% between seasons. The first function explained 64.8% of the total variance between the seasons while the second function explained 35.2%. Total solids (TS) were the highest contributor in discriminate functions 1 and 2. Therefore, discriminate function analysis would enable us to predict the likely season a water sample from metropolitan Makurdi was collected given the values of the water quality parameters. It also enables us to conclude that all the parameters were responsible for significant seasonal variations in River Benue water quality.

关键词： River Benue Water Quality and Variation

Concentration of Heavy Metals in Respirable Dust in Jos Metropolitan Area, Nigeria

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Open Journal of Air Pollution 2014年第1期3卷 10-19页

作者： Godwin M. Mafuyai Ishaq S. Eneji rufus sha’ato Department of Chemistry University of Agriculture Makurdi Nigeria

The concentration of respirable dust at seven sampling stations in Jos metropolitan area, was measured weekly for three consecutive months (October 2012 to December 2012). Characterization of the dust particles shows that the concentration of fine dust ( μm) ranged from 55.0 - 124.9 μg/m3 while the coarse dust (2.5 - 10 μm) varied from 20.0 - 124.4 μg/m3. FAAS analysis of the respirable dust shows that the concentrations of heavy metals ranged from 0.121 - 0.832 mg/kg Pb, 0.019 - 0.111 mg/kg Cr, 0.171 - 1.081 mg/kg Fe, 0.002 - 0.056 mg/kg Mn, 0.002 - 0.438 mg/kg Cd, 0.696 - 1.712 mg/kg Zn, 0.025 - 0.571 mg/kg Cu, and 0.021 - 0. 478 mg/kg Ni, across the sites studied. The main sources of these heavy metals in the sampled area could be attributed to anthropogenic activities like open incineration of waste and vehicular traffic. The concentrations of Cd, Mn and Ni were found to be far above the standard limits prescribed by the WHO for respirable dust. These results convey the health risk the inhabitants in the study area are exposed to. We therefore recommend that measures be taken to regulate these anthropogenic

关键词： Mass Concentration Respirable Dust Heavy Metals Jos Air Quality

Ecological Risk Assessment of Heavy Metals Concentrations in Topsoil of Makurdi and Its Environs

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Journal of Geoscience and Environment Protection 2023年第8期11卷 49-64页

作者： Ada Florence Ogli Adams Udoji Itodo Raymond Ahulle Wuana rufus sha’ato Department of Chemistry Akawe Torkula Polytechnic Makurdi Benue State Nigeria Department of Chemistry/Centre for Agrochemical Technology Joseph Sarwuan Tarka University Makurdi Benue State Nigeria

This work examined the concentrations of As, Cd, Cr, Hg and Pb pollution in soil and estimated the potential ecological risks of these metals in Makurdi and its environs, using established pollution indices. The information derived from pollution indices will help to assess the extent, and intensity of anthropogenic contaminant deposition on surface soil in the study area. The soil samples were collected from sixteen (16) locations across the investigated sites, sampled as appropriate and treated using established methods and analyzed using atomic absorption spectrometry (AAS). The findings have revealed that the concentrations of the metals in the topsoil samples were arranged in the sequence from increasing to decreasing order thus: Cr > Pb > Cd > Hg > As. It was observed that the pollution levels of As and Hg were insignificant, while, the level of pollution caused by Cd, Cr and Pb ranged from low level of contamination to high level of contamination across the investigated sites, except, for the control site (BZ) whose pollution level was insignificant with respect to the heavy metals studied. The results could be used as preliminary baseline data for heavy metal concentrations for future assessment and monitoring. Therefore, there is an urgent need to effect mitigation measures to reduce the ecological environmental risks, taking into consideration that human activities which are the main source of pollutants are still ongoing in the study area.

关键词： Pollution Contamination Single Indices Integrated Indices Makurdi

Kinetics of Sorption of Pendimethalin on Soil Samples Obtained from the Banks of Rivers Katsina-Ala and Benue, Central Nigeria

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Journal of Geoscience and Environment Protection 2016年第1期4卷 37-42页

作者： Justin Kpagh rufus sha’ato Raymond A. Wuana Terrumun A. Tor-Anyiin Department of Chemistry University of Agriculture Makurdi Nigeria

Kinetics of the sorption of the herbicide, pendimethalin (3,4-Dimethyl-2,6-dinitro-N-pentan-3-yl-aniline) on four soil samples obtained from the banks of Rivers Benue and Katsina-Ala, in Central Nigeria was studied by contacting 5.0 g soil samples with 100 mL 7 × 10-6 M herbicide solution. The sorption was monitored by following the herbicide concentration in the aqueous phase spectrophotometrically at one hour intervals for 5 hours (at 25°C, 35°C, 45°C, 55°C and 65°C, respectively). Pseudo-first order kinetics treatment of the data showed that sorption rates as well as the accompanying activation energies were low, indicating that physical adsorption is the operative mechanism for its retention in the soils and that the herbicide tended to reside more in the aqueous phase, which raised its potential to contaminate natural water systems, when applied on the field.

关键词： Kinetics Sorption Pendimethalin Soil Nigeria

Analysis of Heavy Metals in Human Hair Using atomic Absorption Spectrometry (AAS)

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American Journal of Analytical Chemistry 2012年第11期3卷 770-773页

作者： Onuwa O. Peter Ishaq S. Eneji rufus sha’ato Department of Chemistry and Centre for Agrochemical Technology University of Agriculture Makurdi Nigeria

Hair samples of individual were analysed for heavy metals (Cd, Cr, Pb and As) across gender and various occupational distributions by atomic Absorption Spectrophotometric technique (AAS). The results of replicate analysis shows the following mean concentrations (mg/kg): Cd = 27.8 ± 8.0, Cr = 2.70 ± 0.7, Pb = 73.8 ± 42.3 and As = 222 ± 34.1. The coefficients of variation for the total distribution is;Cd = 28%, Cr = 26%, Pb = 57% and As = 15%. The distribution of the metals follows the series in decreasing order of As > Pb > Cd > Cr, while their coefficients of variation is in the order of Pb > Cd >Cr > As. The result shows the presence of all the metals in relatively large amounts with As having the highest concentration between the two genders. The difference between male and female concentration could be due to individual differences in exposure to heavy metal load as a result of habitual or environmental factors.

关键词： Heavy Metals Human Scalp Hair AAS Concentration

GIS Mapping, Biomonitoring and Distribution of Heavy Metal Concentrations Using Neem (Azadirachta indica) Bark in Makurdi Town, Benue State, Nigeria

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Journal of Geoscience and Environment Protection 2023年第7期11卷 213-226页

作者： Ada Florence Ogli Mohammed Ahmed Adams Udoji Itodo Raymond Ahulle Wuana rufus sha’ato Department of Chemistry Akawe Torkula Polytechnic Makurdi Nigeria Department of Geography Bayero University Kano Nigeria Department of Chemistry/Centre for Agrochemical Technology Joseph Sarwuan Tarka University Makurdi Nigeria

The present work determined the concentration and spatial distribution of heavy metals (As, Hg, Cr, Cd and Pb) in soil samples from Makurdi and its environs using geographic information system (GIS). The specific objective is to produce the spatial distribution maps showing the spatial distribution of toxic heavy metals in the study area. Inverse Distance Weighting (IDW), a GIS technique was used to produce dotted maps showing the spatial distribution of heavy metals in neem bark for better visualization of contamination zones and non-contamination zones. The map reveals few hotspot areas showing areas of high concentrations of the heavy metals investigated which were identified in red colours, the following concentration ranges were obtained;As (4.71 - 6.43 mg/kg), Cd (13.9 - 16.84 mg/kg), Cr (46.3 - 60.84 mg/kg), Hg (3.70 - 5.05 mg/kg) and Pb (24.02 - 31.34 mg/kg). These hotspot areas were found close to business outlets, fuel filling and service stations, farm sites where the application of fertilizers and pesticides were persistent coupled with heavy traffic of vehicles and other machinery which was associated with As, Hg, Cd, Pb and Cr been released into the environment thus, suggesting anthropogenic activities controlling the concentration of these heavy metals in the study areas. The cumulative effect of these heavy metals into the barks of neem could pose as danger, because this plant is used as herbs in folk medicine.

关键词： Heavy Metal Contamination Spatial Distribution Inverse Distance Weighting Folk Medicine Makurdi

Analysis of Heavy Metals in Human Scalp Hair Using Energy Dispersive X-Ray Fluorescence Technique

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Journal of Analytical Sciences, Methods and Instrumentation 2012年第4期2卷 187-193页

作者： Peter O. Onuwa Lami A. Nnamonu Ishaq S. Eneji rufus sha’ato Department of Chemistry and Centre for Agrochemical Technology University of Agriculture Makurdi Benue State Nigeria

Analysis of six heavy metals (Cr, Mn, Ni, Cu, Zn and Mo) in human scalp hair was carried out among various occupational distributions to ascertain their heavy metal burden, using energy dispersive x-ray fluorescence technique (ED-XRF). The result of the analysis shows that mean concentrations (mg/kg) of heavy metals obtained were as follows: Cr = 17.1 ± 12.7;Mn = 3.11 ± 0.50;Ni = 11.3 ± 9.3;Zn = 451 ± 128;Cu = 83.3 ± 35.8 and Mo is 9.16 ± *** the mean concentrations of Cr, Cu, and Mo were higher in the females, that of Mn, Ni and Zn were more in the males. Statistical analysis of the results for both genders at 0.05 probably shows significant difference for Ni, Zn and Mo while Cr, Mn and Cu showed no significant difference. The relationships between age, body mass, height, and heavy metal concentrations were also investigated. Statistical analysis of the results indicates that there was no correlation between the body mass (R2 ≤ 0.048), height (R2 ≤ 0.002) and heavy metal concentration in hair. Zn showed the highest deviation among other elements in the individual samples for both genders which reflect the individual variation in the concentration of Zn.

关键词： Human Hair Heavy Metals X-Ray Fluorescence Risk Assessment