Browsing by Author "Nkwoada, A. U."
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Item Open Access Ammonia variations in Owerri metropolis and ecological impact(Conscientia Beam, 2020-04-15) Nnadozie, C. F.; Nkwoada, A. U.; Akagha, C. I.Ammonia emissions inventory is rarely reported in Nigeria and when at high levels is toxic to animals including humans. It is instructive to evaluate the levels of ammonia in metropolitan area as a priority to promote a clearer understanding of its distribution and interaction. The study investigated the levels of ammonia in different parts of Owerri Metropolis and its ecological impact. Ambient atmospheric NH3 concentrations have been measured for Owerri metropolis, away from point sources, for a period of three consecutive months in 2018 calendar year. Measured lowest mean NH3 concentrations have been in August at 0.04633 mg/L, which exceeded the critical loads and occupation exposure limits. There has been no significant change in the spatial variation in NH3 concentrations between the months albeit different locations varied significantly. The ecosystems where lichens and bryophytes are key species within the studied area may be under threat from loss of biodiversity while levels of human exposure to NH3 are completely unacceptable and require reducing and controlling measures. Hence, excess ammonia will induce elevated nitrification and denitrification driving higher greenhouse gas emissionsItem Open Access Characterization of selected honey in SouthEast Nigeria: Theoretical translation(U. P., 2017) Nwoko, C. I. A.; Nkwoada, A. U.; Ubeh, E. O.; Njoku, A.With the vast honey bee species producing honey for international export and consumption in Nigeria, there is need for theoretical translation of quality assessment and characterization of honey for human consumption. The physicochemical and mineral contents of some selected honey in the five South east geopolitical states of Nigeria was performed for above mentioned application. The results were evaluated with 3D plot to identify the statistical significance of the parameters analyzed. The levels of glucose and fructose were accepted by codex alimentation standard and rejected samples B, C, and G. A correlation of similar botanical origin was demonstrated in sample B, C and G and similarly observed in their moisture content been > 21%. The pH and electrical conductivity showed no significant variation. The codex hydroxyl methyl furfural standard identified samples B, E and L to be “aged honey” or falsified honey in circulation. The 3D plot showed the significant variation of hydroxyl methyl furfural content of samples. A hypothesis was observed when the samples and previously analyzed Nigerian samples were compared; metal concentration levels of Group 1 elements > Group 2 > transition metals in Nigerian honey and formed an identification trend.Item Open Access Establishing risk assessment from reclaimed Nekede Mechanic Village Owerri, Nigeria(U. P., 2018-09-14) Nkwoada, A. U.; Alisa, C. O.; Amakom, C. M.; Enenebeaku, C. K.The current resettlement of Nekede Auto-Mechanic village by Imo State government of Nigeria created a sparse piece of land awaiting government utilization. Risk assessment was carried out on the land using existing boreholes and soil to determine land utilization potential. Analysis of the physicochemical water parameters showed that there was no contamination of boreholes. The high value of COD correlated with the high levels of Fe in soil and water samples. Heavy metals concentrations showed that Fe was very much present in the soil while Pb, Cd and Cu had reduced concentrations. Risk assessment for the soil samples showed that Fe had the highest mean and median value. The highest mean value for water was Cu metal. Highest variance value was Cu in soil while Pb had the lowest value in water. Hazard quotient of water samples showed that hazards existed for Cd, Cu and Pb but at a moderate level for Fe. Estimated daily/weekly water intake values were all below WHO/FAO standards. The soil enrichment factor showed no enrichment for Pb, minimal enrichment for Cd, moderate enrichment for Cu and significant contamination for Fe. Ecological risk assessments for the heavy metals were at low ecological risk. Potential ecological index depicts Fe and Cd at a considerable level of ecological risk. Likewise, contaminants existed at the nearby Otamiri river due to dredging and nearby waste dumps. The anthropogenic activity at the Otamiri river posed a serious environmental concern if not controlled and reclaimed. Hence, the reclamation of Nekede auto mechanic village will not be suitable for agricultural or recreational purposes.Item Open Access Evaluation of organic and inorganic pollution indicators in a homeland river(International Science Community Association, 2020) Akagha, C. I.; Nkwoada, A. U.; Nnadozie, C. F.The objective of this study was to develop a biannual database for selected organic and inorganic river pollution indicators. The DO, BOD and COD levels alongside TSS and TDS concentrations were determined using standard protocols. The compiled database consisted of 5 aforementionedduring the biannual study generating over 60 data per specific parameter with 60 data per variable, per season per annum. April/May recorded highest values of TSS at "UT" sampling pointvalues of TSS at 60.38 mg/L exceeding the APHA, EU, EPA and FME discharge limits, except WHO standards. Highest TDS (68.20 mg/L) was in 2014 (Oct/NOV) at "DS" sampling point which exceeded FME and EPA pebelow WHO, EU and APHA standards. Observation shows that 2015 was an active DO year much more than 2014 and DO decreased significantly as water flows downstream. Moreover, the highest COD concentration was 290 mg/L at "NB" sampling point during Oct/Nov that was high but below APHA standard. However, the BOD levels between the seasons showed no seasonal variation within each year, which might be due to active and regular discharge of organic pollutants from abattoir source throughout the biannual study. ANOVA analyses showed that BOD and TSS data were statistically more accurate than other parameters. In conclusion, the river is unsafe, unclean and unacceptable for public consumption, recreation, sensitive fish habitation, requires pollution and preventive measures.Item Open Access Fluorescence lifetime investigation and characterization of dysprosium and terbium doped taggants(JACS Directory, 2016) Nkwoada, A. U.; Officer, SimonAn investigation was made into the use of fluorescent materials called taggants that would give a better discrimination against the background interference arising from hydrocarbons and having a longer lifetime than other sources of interference. Borosilicate and tellurite glass host were doped with dysprosium and terbium rare earth elements. Their absorptions and fluorescence lifetime characterisation was used to determine their interaction and compatibility with cyclohexane and crude oil. The fluorescence lifetime test established Dysprosium doped glasses as the optimum taggants for cyclohexane and terbium doped tellurite glass as the ideal taggants in crude oil and both achieving better lifetime discriminations respectively.Item Open Access GIS and MATLAB modeling of criteria pollutants: A study of Lower Onitsha Basin during rains(Journal BiNET Scientifc Publishing, 2018-10-14) Anyika, L. C.; Alisa, C. O.; Nkwoada, A. U.; Opara, A. I.; Ejike, E. N.; Onuoha, G. N.The study of air pollutants SO2, NO2 and PM10 in lower Onitsha basin, a densely populated city was performed using GPS and Matlab modeling. The pollutants were studied in nine specific locations for 3 months of rains over 3 consecutive years with each georeferenced. The Matlab pollution model was generated by integrating the spatial database and measured pollution attributes database using a polynomial expression. SO2 highest concentration (141 µg/m3) peaked in Upper Iweka at sampling point 1 before dispersing to lower concentrated regions in Awada and Resthouse. NO2 peaked at 207 µg/m3 in Upper Iweka at sampling point 3 and driven by wind towards Borromeo area to very low concentration of 38 ug/m3. The PM10 peaked in Upper Iweka (180 µg/m3) and driven by rains towards Borromeo before increasing again in concentration levels at Awada. The AQI showed that SO2 pollutants had acceptable air quality at all sampling points while NO2 and PM10 air quality affected sensitive groups. SO2 concentration levels exceeded the National air quality standard in Nigeria (NAQS) while NO2 and PM10 were below the NAQS standard. The GIS plot showed that 3 metrological forces were driving pollutants from Upper Iweka and Awada to other sampling areas in the order of SO2> NO2> PM10. The Matlab wind speed plot showed that there was an upward wind in upper Iweka driving the pollutants towards dispersal at some other region. Thus, Upper Iweka is an active point source pollution area and dispersed to Borromeo and Awada by scavenging rains under prevailing wind speed, wind direction and humidity. Hence calls for improved monitoring and regulation to address poll.Item Open Access Investigation of Aba river contamination using Eichhornia crassipes as bio-indicator(U. P., 2017-06-05) Akagha, C. I.; Ajiwe, V. I. E.; Okoye, P. A. C.; Alisa, C. O.; Nkwoada, A. U.The seasonal variation of heavy metal contamination levels in Aba River of Abia State in Nigeria was investigated using Eichhornia crassipies. Routine sampling was performed on bi-monthly bases to cover the Nigerian Rainy season and Harmattan season. Iron (Fe) showed more abundance with maximum concentration (69.5 mg/kg) mainly in Dec/Jan at UST, PZA, ABT and DST sampling points. The lowest concentration of iron was obtained in Apr/May for UST and DST and in Oct/Nov for PZA and ABT. Manganese showed maximum concentration (7 mg/kg) in the dry season at PZA and NBL during Oct/Nov months. The lowest concentration was in Dec/Jan at UST, PZA and ABT which were Harmattan seasons. The varied concentrations of zinc (Zn) demonstrated no pattern or trend except at Oct/Nov of ABT at value of 9.7 mg/kg, while lead (Pb) metal was significantly identified during the months of Feb/March (end of Harmattan) and April/May (beginning of Rains) during the seasonal study. Chromium metal (Cr) was uniformly distributed but significant at NBL during months of Jun/Jul. Nickel (Ni) metal was detected mainly at UST, PZA and NBL at trace levels. Copper was mainly detected during rainy seasons of Apr/May and Jun/July but remained at low concentrations when compared to other metals. Hence, UST and PZA sampling points contained the most active level of heavy metals, while Harmattan season showed the highest phytochemical activity of the heavy metals. Therefore Eichhornia crassipes showed metal removal in the following order Fe > Mn> Cr > Ni > Pb > Zn > Cd.Item Open Access Mineralogical and physicochemical assessment of Ihioma coal in Imo State of Nigeria(2016-12) Nwoko, C. I. A.; Onyedika, G. O.; Nkwoada, A. U.; Anyanwu, G. C.The physicochemical characterization of coal samples from deposits provides mineral distribution and composition data for utilization by scientists and policy makers. The characterization of coal samples of Ihioma coal deposits in Imo state, Nigeria was performed using proximate and ultimate analyses. XRD and ICP-AES were used to characterize the coal samples for potential energy utilization. Proximate analyze determined fixed carbon content and volatile matter to be 51.5% and 38.5% respectively, an indication of a good coking material. The carbon % in the ultimate analyses was at 64.6% while O2, H2, N2 and S were all below 5% which showed the coal potential to emit lower emissions. ICP-AES chemical composition determined SiO2 to be the most abundant followed by Na2O. The XRD peaks classified Ihioma coal as having Quartz, Albite and Haematite. Material mapping by XRD showed that Al and Si were evenly distributed while S, Co and Fe were unevenly distributed. Thus Ihioma coal has features of ignition and can undergo spontaneous combustion, hence a good source of thermal energy. Results also confirmed Ihioma coal as a potential material for pigments and can be utilized for ceramics, pottery and ornamentals.Item Open Access Novel non-parametric assessment of heavy metals in coated card wastes(U. P., 2017-11-09) Nwoko, C. I. A.; Nkwoada, A. U.; Njoku, P. C.; Obichini, A.Non-parametric tests were applied for the first time to coated mobile card waste in order to determine the correlation within risk assessment and instrumentation. The AAS concentrations of all the metals were higher than their XRF concentrations except in Al and Ag metals. Cr had the highest distribution pattern while Ag metal had the lowest respectively. The target hazard quotient (THQ) for all metals were below minor hazard level. On the contrary, only Fe and Zn were below the Oral reference dose (RfD) value and the daily metal intake (DMI) respectively. The WilcoxonMann-Whitney test showed no significant difference between the concentration of the metals in XRF and AAS analysis results but identified the unusual behavior of Ag and Al metals; hence it depicted that both AAS and XRF analysis results were not sensitive to detect the different metal concentrations in the cards. Hence, similar coating specifications are utilized. The Kruskal Wallis test and Spearman correlation coefficient showed that the results from AAS and XRF were significantly different. Hence it showed that instrumentation showed sensitivity of metal concentrations from the recharge cards. This correlated with THQ, DMI, health risk index (HRI) risk assessment parameters that different coating specifications were used causing different values at same sampling points. Therefore, the results established that non-parametric tests are good analytical tools.Item Open Access Phytoextraction and risk assessment synergy of three edible plants in mining area(U. P., 2018-08-11) Nwoko, C. I. A.; Nkwoada, A. U.; Onu, L. U.; Njoku, P. C.; Ogbonnaya, D. O.The phytoextraction and risk assessment synergy of Arachis hypogea (groundnut), Zea maize (Corn) and Citrullus colocynthis L. (Melon) was investigated at a mining area contaminated with Cd, Cu, Pb and Zn heavy metals. The metal concentrations in plant matter and soil were determined using AAS. The average pH at 5.2 showed a slightly acidic soil while the total organic content and electrical conductivity were low. The studied metals exceeded the Nigerian FEPA guidelines as well as EU threshold values at the sites. Increase in Cd concentration in the North and South caused a corresponding decrease in plant yield. The maize appreciably accumulated more Pb than melon and groundnut. The phytoplants at the West sampling point accumulated more Zinc and melon grown at the west accumulated highest zinc concentrations of up to 1100 mg/kg. The Presence of Cu metal at low concentrations favoured an equivalent increase in weight of harvested groundnut seed. The Coefficient of Variation (CV) showed a correlation that hyperaccumulators had equivalent higher CV distribution. The values of Cd, Cu and Pb exceeded the Health Risk Index value of 1 in all the three edible phytoplants. The Cd demonstrated the lowest Bioconcentration Factor of (0.03) within the sampling area, among studied metals and the three edible plants. Thus Target Hazard Quotient (THQ) results agreed with the Daily Intake of Metals (DIM) results, that consumption of any of the three edible plants are unsafe and poses a health risk to locals; hence, the synergy of THQ and DIM in evaluating experimental data is detected in this study.Item Open Access Pollution in Nigerian auto-mechanic villages: A review(U. P., 2018) Nkwoada, A. U.; Alisa, C. O.; Amakom, C. M.The increasing number of malfunctioning automobiles with subsequent increase in emission levels and waste handling is an environmental concern in Nigeria. The spills from lubricants, gasoline, diesel and byproducts of used and spent engine oil constitute the major pollutants in auto mechanic villages in Nigeria. Its environmental pollution has been predominant through soil and groundwater contamination and also poses a major anthropogenic threat. The studied heavy metals on contaminated soil showed that studies had focused on common metals of Cu, Cd, Pb and Zn in the east and west regions, while trace metals were studied in the south and radioactive elements in the north. Statistical evaluation showed high occurrences of Cu, Cd, Pb and Zn in the four geo-political zones of Nigeria. The detrimental effects of auto-mechanic village activities were on humans and also disrupted growth and flowering of arable plants. The remediation application showed that soil type and contaminant characteristics play a major role in determining the type of remediation procedure to be applied. Hence, Nigeria should provide standard repairs and services to automobiles in-line with emerging technology and best environmental practices.Item Open Access Radionuclide depth profile baseline and radiation hazard indices of the reclaimed old Nekede Mechanic Village, Owerri, Imo State, Nigeria(U. P., 2021-02-06) Amakom, Chijioke M.; Nkwoada, A. U.; Nwaogbo, Chidiebere I.; Iheonu, Nneka O.Radionuclide concentration in soil samples collected at the old Nekede auto-mechanic village in Owerri were determined using gamma spectroscopy. A total of 15 soil samples were collected at depths of 10-cm, 20-cm and 30-cm at 5 different sites respectively. From the results, the mean activity concentrations of 40K, 226Ra, and 232Th were 132.66±5.61 Bq/Kg, 26.38±3.88 Bq/Kg, and 73.24±4.91 Bq/Kg respectively for samples collected at 10cm depth. At 20cm depth the mean values obtained were 111.95±6.51 Bq/Kg, 32.63±3.48 Bq/Kg, and 89.76±5.20 Bq/Kg for 40K, 226Ra, and 232Th respectively, while 102.88±4.62 Bq/Kg, 30.03±2.77 Bq/Kg, and 76.08±6.65 Bq/Kg were obtained at the 30 cm depth for 40K, 226Ra, and 232Th respectively. The calculated absorbed dose rate and annual effective dose have an average value of 66.6687 nGyh-1 and 0.0912 mSv.y-1 . The 10cm depth presented the lowest dose rate and annual effective dose rate with values of 61.9564 nGyh-1 and 0.0847 mSv.y-1 respectively. While the highest values were obtained at 30cm depth with values of 64.0913 nGyh-1 and 0.0876 mSv.y-1 respectively. The value of the annual effective dose lies within the world average value of 1.0 mSvy-1annual effective dose equivalent rate. The hazard indices corresponding to the collected samples was also estimated to have a mean value of 0.142, which is below the ecommended world average.Item Open Access Spatio-temporal study of criteria pollutants in Nigerian city(U. P., 2020-06-29) Anyika, L. C.; Alisa, C. O.; Nkwoada, A. U.; Opara, A. I.; Ejike, E. N.Aims: An investigation of characteristic long term air pollutants known for temporal and spatial behaviors was conducted due to increased pollution scenarios in Nigerian cities as a result of deprived environmental enforcement of statutory obligations. Study Design: One of the worlds’ most polluted cities (Onitsha lower basin) in Nigeria was selected for spatio-temporal study of three criteria pollutants combined with GIS and MATLAB alongside associated meteorological conditions during harmattan. Methodology: 72-hourly analyses of the nine different locations having 4 sampling sites and 500 meters apart were done from December to February which generated over 19, 440 experimental data per quarter of each annual study. Results: Upper Iweka/Nitel area recorded the highest concentration of SO2 pollutant at (94.2 µg/m3) due to longer residence times and low wind mixing height. Borromeo hospital showed the least active NO2 region but converges at points 1 due to North-east wind dissimilar to sampling points 1 having the lowest PM10 distribution. Measured temperature parameter correlates inversely with relative humidity and precipitation. The GIS spatial representation corresponded to temporal variability of gaseous and particulate pollutants. Conclusion: All sampled areas had AQI above 50; hence the study identified SO2, NO2, and PM10 as Primary pollutants of Onitsha lower basin.Item Open Access Studies on adsorptive behavior of Cd2+ on graphene oxide: Alternative novel approach(U. P., 2018-03-03) Nkwoada, A. U.; Alisa, C. O.; Enenebeaku, C. K.; Oguzie, E, E.Certain adsorptive mechanisms and interactions often exist within linearized kinetic functions which are largely unreported. A novel inverse saturation modeling was applied to evaluate the adsorptive behavior of super-saturation, saturation, and desorptive processes on linear kinetic function plots using pseudo 1st order, pseudo 2nd order, Elovich and Intra-particle diffusion. Graphene oxide was prepared by room temperature synthesis and used as adsorbent over Cd2+ adsorbate. Batch adsorption process was conducted and four error functions were utilized. The sum of squares of the errors and Sum of absolute errors identified pseudo 2nd order as having the least deviation at 0.113 and 0.337 respectively. The modelled pseudo 1st order reaction had R2 = 0.985 while the inverse saturation model had R2 value of 0.998, both been a better data fit than non-modelled pseudo 1st order R2 at 0.917. The slower reaction kinetics in pseudo 1st order was due to supersaturation during adsorption as shown by inverse saturation point. The correlation coefficient of modeled kinetic plot of pseudo 2nd order, Intra particle diffusion and Elovich had R2 = 1. The Elovich inverse saturation plot showed that the graph was an L-isotherm type indicating progressive saturation. The rate determining step experienced by Intra-particle diffusion was accommodated by wide range of inverse saturation plots showing adsorption, supersaturation and desorption as points of greatest influence. The inverse saturation plot of pseudo 2nd order plot had absolute slope of 2.656 and large intercept of 24.815 driving it's faster reaction kinetics. Hence, the inverse saturation point modelling provided a much better interpretation of adsorptive behavior of graphene oxide adsorbent over Cd2+ adsorbate.