期刊文献+
共找到11篇文章
< 1 >
每页显示 20 50 100
Analysis of Heavy Metals in Human Hair Using Atomic Absorption Spectrometry (AAS) 被引量:1
1
作者 Onuwa O. Peter Ishaq S. Eneji rufus sha’ato 《American Journal of Analytical Chemistry》 2012年第11期770-773,共4页
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 anal... 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. 展开更多
关键词 HEAVY METALS Human SCALP HAIR AAS Concentration
下载PDF
Ecological Risk Assessment of Heavy Metals Concentrations in Topsoil of Makurdi and Its Environs
2
作者 Ada Florence Ogli Adams Udoji Itodo +1 位作者 Raymond Ahulle Wuana rufus sha’ato 《Journal of Geoscience and Environment Protection》 2023年第8期49-64,共14页
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 infor... 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. 展开更多
关键词 POLLUTION CONTAMINATION Single Indices Integrated Indices Makurdi
下载PDF
GIS Mapping, Biomonitoring and Distribution of Heavy Metal Concentrations Using Neem (Azadirachta indica) Bark in Makurdi Town, Benue State, Nigeria
3
作者 Ada Florence Ogli Mohammed Ahmed +2 位作者 Adams Udoji Itodo Raymond Ahulle Wuana rufus sha’ato 《Journal of Geoscience and Environment Protection》 2023年第7期213-226,共14页
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 obje... 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. 展开更多
关键词 Heavy Metal Contamination Spatial Distribution Inverse Distance Weighting Folk Medicine Makurdi
下载PDF
Kinetics of Sorption of Pendimethalin on Soil Samples Obtained from the Banks of Rivers Katsina-Ala and Benue, Central Nigeria
4
作者 Justin Kpagh rufus sha’ato +1 位作者 Raymond A. Wuana Terrumun A. Tor-Anyiin 《Journal of Geoscience and Environment Protection》 2016年第1期37-42,共6页
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... 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<sup>-6</sup> 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. 展开更多
关键词 KINETICS SORPTION PENDIMETHALIN Soil NIGERIA
下载PDF
Analysis of Selenium Content in Root and Tuber Plants in Central Nigeria 被引量:1
5
作者 Saidu Zarmai Ishaq S. Eneji rufus sha’ato 《American Journal of Analytical Chemistry》 2013年第12期739-743,共5页
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 du... 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 <1.00, 1.09, 1.91, 2.35 and 11.0 μg/kg were lower while a few others like 52.6, 54.2, 72.3 and 81.8 μg/kg were higher than literature values. The variations could be due to the type of species/variety, geographical location, total selenium concentration in the soil and its bioavailability. In view of the importance of Se to human health and considering the levels found in the staples investigated, we recommend that sweet potato be popularized as a staple, much more than cassava as it is now the case in Central Nigeria. 展开更多
关键词 SELENIUM Content ROOTS and TUBERS CENTRAL NIGERIA HG-AAS
下载PDF
Environmentally Friendly Formulations of Trifluralin Based on Alginate Modified Starch 被引量:1
6
作者 Ikenna Onyido rufus sha’ato Lami A. Nnamonu 《Journal of Environmental Protection》 2012年第9期1085-1093,共9页
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 enca... 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 80.87% retardation of TRF release. Encapsulation of TRF in starch/alginate beads is a veritable way of reducing negative environmental effects. 展开更多
关键词 ALGINATE GROUNDNUT Oil STARCH SLOW RELEASE TRIFLURALIN
下载PDF
Spatial and Temporal Variation in Water Quality of River Benue, Nigeria 被引量:1
7
作者 Ishaq S. Eneji Agada P. Onuche rufus sha’ato 《Journal of Environmental Protection》 2012年第8期915-921,共7页
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 differe... 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. 展开更多
关键词 RIVER Benue WATER QUALITY and VARIATION
下载PDF
Analysis of Heavy Metals in Human Scalp Hair Using Energy Dispersive X-Ray Fluorescence Technique 被引量:1
8
作者 Peter O. Onuwa Lami A. Nnamonu +1 位作者 Ishaq S. Eneji rufus sha’ato 《Journal of Analytical Sciences, Methods and Instrumentation》 2012年第4期187-193,共7页
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 t... 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 ± 9.1.While 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. 展开更多
关键词 HUMAN HAIR HEAVY METALS X-Ray FLUORESCENCE Risk Assessment
下载PDF
Assessment of Potential Ecological Risk of Heavy Metals in Soils from Waste Dumpsites in Military Formations in Makurdi, Nigeria
9
作者 Raymond C. Nwankwo Sylvester M. Tongu +3 位作者 Ishaq S. Eneji Lami A. Nnamonu Raymond A. Wuana rufus sha’ato 《Journal of Environmental Protection》 2019年第4期514-531,共18页
Chemical fractionation of toxic metals (As, Cd and Zn) along the soil profile at waste dumpsites in military formations for dry and wet seasons using Tessier’s sequential extraction procedure was determined using AAS... Chemical fractionation of toxic metals (As, Cd and Zn) along the soil profile at waste dumpsites in military formations for dry and wet seasons using Tessier’s sequential extraction procedure was determined using AAS techniques. The order of yield across the fractions was mainly: exchangeable (F1) 2) 3) 4) 5). Statistical analysis (p < 0.05) indicated that there was no significant variation between the values of results obtained from dumpsites A and B of each sampling station. However, the variation between the dumpsites and control was significant (p > 0.05) in most stations. The pollution index was assessed using the degree of contamination (Cd), the modified degree of contamination (mCd), potential ecological risk and mobility factor. The Cd indicated that NFB top soil was considerably contaminated (16.3) while the soils (20 - 40 and 40 - 80 cm) recorded moderate (13.6) and low (5.60) contaminations respectively. Top soil of NSM was moderately contaminated while the contamination status of NPS, NFB and SFB waste dump soils across the depths was “low”. The mCd index for NFB dump soil was “moderate” (2.33) and subsoils (20 - 40 and 40 - 80 cm) were “low” (1.94) and “Nil to very low” (0.800) respectively. The mCd for the other three dumpsites was “Nil to very low” except the top soil of NSM which was “low”. The order of the toxic metals mobility in the studied soils using the Mobility factor (Mf) for dry and wet seasons was Cd > As > Zn and Zn > Cd > As respectively. 展开更多
关键词 TOXIC Metals POLLUTION Index MILITARY Formations Dumpsites Soil
下载PDF
Concentration of Heavy Metals in Respirable Dust in Jos Metropolitan Area, Nigeria
10
作者 Godwin M. Mafuyai Ishaq S. Eneji rufus sha’ato 《Open Journal of Air Pollution》 2014年第1期10-19,共10页
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 ... 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 展开更多
关键词 Mass CONCENTRATION Respirable DUST HEAVY METALS Jos Air Quality
下载PDF
Alginate Reinforced Chitosan and Starch Beads in Slow Release Formulation of Imazaquin Herbicide—Preparation and Characterization
11
作者 Lami A. Nnamonu rufus sha’ato Ikenna Onyido 《Materials Sciences and Applications》 2012年第8期566-574,共9页
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 formula... 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. 展开更多
关键词 ALGINATE CHITOSAN STARCH Encapsulation IMAZAQUIN
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部