Browsing by Author "Adomako, D."
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Item Biomonitoring of airborne heavy metals along a major road in Accra, Ghana(Environmental Monitoring and Assessment, 2008-02) Affum, H.A.; Oduro-Afriyie, K.; Nartey, V.K.; Adomako, D.; Nyarko, B.J.B.Lichens collected in an unpolluted forest (background) in November 2004, transplanted at 41 sampling sites along the Madina-Tetteh Quarshie road, retrieved in February 2005 and analysed were found to contain higher concentrations of Manganese (Mn), Vanadium (V), lead, Cadmium (Cd), Chromium (Cr) and Nickel (Ni) than in the background area. Observations showed that of all the heavy metals studied, Manganese concentrations were highest at all sampling points with maximum values around a traffic light, an intersection and car fitting/mechanic workshops. Significant correlations were found between Ni and Mn, Mn and Cr and Mn and V. Statistical analysis also revealed a relatively even dispersion of the studied elements on the eastern side of the road than on the western side. © Springer Science+Business Media B.V. 2007.Item Chemical and Isotopic Composition of Rainwater in the Coastal, Forest and Mountainous Areas of Volta Region of Ghana(University of Ghana, 2014-07) Kretchy, S. M.; Akiti, T. T.; Adomako, D.Harvesting rainwater for domestic use is one of the oldest technologies developed by man. In Ghana, groundwater utilization challenges posed by dry wells and high levels of contaminants such as iron, fluoride and other minerals in some geological formations makes harnessing of rainwater for household use inevitable. Whiles researchers are looking for efficient ways of dealing with contaminants associated with these water sources, focus is gradually shifting to the development of enhanced methods for rainwater harvesting. In this study, rainwater samples were collected from Akatsi ( a coastal zone), Amedzofe (high altitude zone) and Kpando ( a forest zone) in the Volta region of Ghana and analyzed for the physico-chemical parameters such as pH, electrical conductivity (EC), total dissolved solids (TDS), colour, turbidity, alkalinity, Ca2+, K+, Na+, Mg2+, NO3-, NH4+, pH, Cl-, and SO42-. The results showed that, pH values of the Akatsi, Amedzofe and Kpando rainfall ranges from 5.40 to 6.85, 4.3 to 6.3 and 4.76 to 6.00 respectively. Amedzofe showed a relatively low pH with 13.70% ranging from 4 to 5, 82.40% of the rainfall events fell within pH of 5 to 6 and 3.90% had pH less than 7 but greater than 6. About 96.10% of the total rainfall events had pH less than 6. EC, TDS, turbidity and colour were generally low with higher values recorded at Akatsi while Amedzofe recorded the lowest values. The concentration of major ions and element-to-sodium ratios showed clear variations with higher levels found in Akatsi (coastal zone) and lower levels found in Amedzofe. Anion order of dominance in Akatsi, Kpando and Amedzofe are HCO3- >SO42- >Cl->NO3-, HCO3- >SO42- >Cl->NO3-and HCO3- >Cl-> SO42- >NO3- respectively, while cation order of dominance are Na+>Mg2+>Ca2+, Ca2+> Na+>Mg2+and Na+> Ca2+>Mg2+ for Akatsi, Amedzofe and Kpando respectively. Isotopic composition of rainwater was also determined for the three areas. Akatsi (coastal zone) presents high values of δ18O and δ2H, whereas rainwater in Amedzofe was characterized by low values of δ18O and δ2H, Kpando on the other hand was intermediately high. The Local Meteoric Water Line for the study area using rainfall greater than 20mm was defined as δ2H =7.453 δ18O + 8.621 (n=45; R2=0.907, rain > 20mm). Isotope fractionation in precipitation, including depletion in both δ18O and δ2H is primarily due to the rainout and the altitude effects with temperature effect being insignificant. The calculated altitude effect shows a gradual lapse rate of δ18O and δ 2H of about -0.2‰/100 m and -1.5 ‰/100 m for Akatsi and Amezofe respectively. Amedzofe and Kpando showed an altitude effect of -0.15‰ /100 m. and -2 ‰/100 m for δ18O and δ2H respectively. The groundwater in the study area is mainly of meteoric origin with different months of recharge. The plot of δ18O and EC shows that, mineral dissolution is the main factor controlling the groundwater salinization in Akatsi while Amedzofe and Kpando groundwater chemistry are mainly controlled by evaporation.Item Estimating groundwater recharge from water isotope (δ2H, δ18) depth profiles in the Densu River basin, Ghana [Estimation de la recharge des eaux souterraines à partir des profils en profondeur des isotopes de l'eau (d2H, d18O) dans le bassin de la Rivière Densu, Ghana](Hydrological Sciences Journal, 2010) Adomako, D.; Maloszewski, P.; Stumpp, C.; Osae, S.; Akiti, T.T.Accurate estimation of groundwater recharge is essential for the proper management of aquifers. A study of water isotope (δ2H, δ18O) depth profiles was carried out to estimate groundwater recharge in the Densu River basin in Ghana, at three chosen observation sites that differ in their altitude, geology, climate and vegetation. Water isotopes and water contents were analysed with depth to determine water flow in the unsaturated zone. The measured data showed isotope enrichment in the pore water near the soil surface due to evaporation. Seasonal variations in the isotope signal of the pore water were also observed to a depth of 2.75 m. Below that depth, the seasonal variation of the isotope signal was attenuated due to diffusion/dispersion and low water flow velocities. Groundwater recharge rates were determined by numerical modelling of the unsaturated water flow and water isotope transport. Different groundwater recharge rates were computed at the three observation sites and were found to vary between 94 and 182 mm/year (± max. 7%). Further, the approximate peak-shift method was applied to give information about groundwater recharge rates. Although this simple method neglects variations in flow conditions and only considers advective transport, it yielded mean ground water recharge rates of 110-250 mm/year (± max. 30%), which were in the same order of magnitude as computed numerical modelling values. Integrating these site-specific groundwater recharge rates to the whole catchment indicates that more water is potentially renewed than consumed nowadays. With increases in population and irrigation, more clean water is required, and knowledge about groundwater recharge rates essential for improving the groundwater management in the Densu River basin can be easily obtained by measuring water isotope depth profiles and applying a simple peak-shift approach. © 2010 IAHS Press.Item Geochemical and isotopic studies of groundwater conditions in the Densu River Basin of Ghana(Environmental Earth Sciences, 2011-03) Adomako, D.; Osae, S.; Akiti, T.T.; Faye, S.; Maloszewski, P.The Densu River Basin (DRB) is an important agricultural area in Ghana and has a high population density. Water shortages have occurred in the basin due to drying out of surface water, heavy pollution and low yield in most of the production wells, which are crucial factors restricting sustainable socioeconomic development. This study was carried out to investigate the geochemical characteristics and evolution, as well as recharge processes in the DRB system with regard to the tectonics, geomorphology, lithology and flow system. It mainly used hydrochemistry, environmental isotopes and a series of comprehensive data interpretation, e. g., statistics, ionic ratios and Piper diagram to obtain a better understanding of the functioning of the system. The following hydrochemical processes were identified as the main factors controlling the water quality of the groundwater system: weathering of silicate minerals, dissolution, ion exchange and, to a lesser extent, evaporation, which seems to be more pronounced downgradient of the flow system. As groundwater flows from the recharge to discharge areas, chemical patterns evolve in the order of Ca2+-HCO3 -, Ca2+/Mg2+-HCO3 - to Ca2+/Na+-Cl-, Ca2+-Na+-HCO3 - and Na+-Cl- according to lithology. The environmental isotope (δ18O, δ2H, 3H) measurements further revealed that groundwater in the DRB was a relatively well-mixed system as evidenced by the encoded narrow range of values. However, deviation from the rainwater signature indicates combined local processes such as direct percolation through preferential channels, evaporation, and probable surface water and anthropogenic contribution to the system. © 2010 Springer-Verlag.Item Hydrogeochemical and Isotopic Studies of Ground and Surface Waters in the Lower Anayari Catchment Area, Upper East Region of Ghana(University of Ghana, 2016-07) Abdul-Wahab, D.; Adomako, D.; Adotey, D.K.; University of Ghana, College of Basic and Applied Sciences, Department of Nuclear Sciences and ApplicationsThe Lower Anayari catchment (LAC) located in the Upper East Region of Ghana, is part of the transboundary (Ghana and Burkina Faso) Anayari catchment. The other transboundary catchments are Atankwidi and Yarigatanga. These catchments are noted for intense farming activities. The population within Lower Anayari catchment area is estimated to be about 19,445. An estimate of about 80% of the population depends on groundwater for domestic and agricultural purposes. Agriculture has direct or indirect effects on the chemical composition of groundwater and aquifer geochemistry. This study was carried out to investigate the dominant geochemical processes and anthropogenic activities that influence groundwater chemistry in LAC. The study employed hydrochemistry and isotopic techniques to assess the chemical quality of groundwater in the Lower Anayari catchment. A total of fifty-one (51) samples comprising of thirty-seven (37) boreholes, four (4) hand-dug well and ten (10) surface waters were sampled from six (6) principal communities (Kulwase, Manyoro, Mirigu, Nakolo, Paga and Pungu) for the study. The samples were analysed in-situ for pH, conductivity and salinity using a HACH potable meter; and bicarbonate using a titrimetry. Analytical methods employed for the determination of major and minor ions were: Na+ and K+ (Flame photometry), Ca2+ (complexometric titration), and F-, Cl-, NO3-, PO43-, and SO42- (ion chromatography). Atomic absorption spectrometry was used for the determination of Mg2+ and heavy metals (Fe, Co, Cd, As, Ni, and Pb). Stable isotope of 2H and 18O composition of the water samples were determined using Liquid-Water stable isotope analyser [Off-Axis Integrated Cavity Output Spectroscopy (off axis ICOS) via Laser Absorption]. The general trend of major cations and anions, and trace element concentration were Na+ > Ca2+ > K+ > Mg2+, HCO3- > Cl- > NO3- > SO42-, and Fe > Pb > As > Co > Cd > Ni respectively. The concentration of Ni [0.001 - 0.019], As [0.001 - 0.008], Co [0.005 - 0.010], and Fe [0.006 - 0.586] mg/L, were averagely below WHO standard values for drinking water. The concentration of Cd [0.002 - 0.006] and Pb [0.001 - 0.020] mg/L, were averagely above WHO standard values (0.003 and 0.01 mg/L respectively) for drinking water. The data was subjected to Principal Component Analysis (PCA) this help delineate principal physico-chemical processes (related to minerals dissolutions, organic and synthetic fertilizers influences) implicated in groundwater quality. Hierarchical Cluster Analysis (HCA) further classified the groundwaters of the study area into two groups. The groups show different degrees of water-rock interaction or mineralisation. Water Quality Index (WQI) estimations indicated that the groundwater in the study area is suitable for drinking with the exception of groundwater in Nakolo and Mirigu which showed deteriorating water quality. Piper Trilinear plot indicated three (3) hydrochemical facies Ca-Mg-HCO3, Na-Ca-HCO3 and Na-HCO3 and are consequence of silicate weathering and silicate mineral dissolution, cation exchange and to a lesser extent fertilizer application which is more evident in Nakolo and Mirigu communities. The Wilcox diagram, and the United States Salinity Laboratory diagram (USSL) method for assessment of the groundwater suitability for irrigation revealed that the groundwater from the LAC are suitable for irrigation. Stable isotopes composition measurements for groundwater River Anayari and irrigation dams were clustered closely along the global meteoric water line (GMWL) suggesting an integrative recharge from meteoric origin, with a few showing evaporation effects before recharge.Item Multi-element analysis of Ghanaian crude oils by instrumental neutron activation analysis(Journal of Radioanalytical and Nuclear Chemistry, 2012-06) Appenteng, M.K.; Adomako, D.; Saka, D.; Golow, A.A.; Hayford, M.S.; Sarfo, D.K.; Carboo, D.; Yamoah, A.K.K.Instrumental neutron activation analysis based on thermal neutrons from the Ghana Research Reactor-1 facility was utilized to analyze 18 trace elements namely Al, As, Br, Ca, Cd, Cl, Co, Cu, Fe, K, Mg, Mn, Na, Ni, S, Si, V, and Zn in two different crude oil samples from the Saltpond and Jubilee field in the Saltpond, Central region and Cape Three Points, Western region of Ghana, respectively. The sulfur concentration for both samples were low and within globally accepted range of 0.1-0.5%wt for sweet crude oil. The results of the elemental analysis showed that the two samples are relatively low in trace element concentrations compared to crude oils of other countries. Higher Fe concentration in the Jubilee crude oil indicates younger oil. The V/Ni ratios obtained for crude oils from both locations imply a possible marine organic origin and also suggest the Saltpond crude oil is more matured than the Jubilee crude oil. © 2011 Akadémiai Kiadó, Budapest, Hungary.Item Prevalence and Characterization of Pathogenic Escherichia Coli in Selected Indigenous Dairy Product(University of Ghana, 2020-10) Adomako, D.Diarrhoeagenic E. coli is a major health concern. It causes mortality and morbidity especially in children of age five years and below in countries that are developing. Research has revealed that out of the six categories of diarrhoeagenic E. coli, Enterohaemorragic E. coli (EHEC) and Enteropathogenic E. coli (EPEC) are the most widespread cause of diarrhea. This work identified the existence of some E. coli that causes diarrhea in informal dairy products from selected traditional open markets and streets of Greater Accra and characterized the survival of E. coli O157:H7 in Mueller Hinton broth and wagashi, a soft unripened indigenous cheese. A total of 85 local dairy products, specifically raw milk, boiled milk, brukina, nunu and wagashi were examined. These were purchased from cow rearing locations and markets within Accra. E. coli was detected by enrichment in Brain Heart Infusion broth followed by plating on MacConkey agar. E. coli O157:H7 was determined on Sorbitol MacConkey agar which appeared colorless. Survival of E. coli O157:H7 to sub-lethal stresses of low pH, high salt and heat was determined in broth and at multiple processing stages of traditional wagashi. Out of the 85 milk samples, 60 (70.6%) tested positive for E. coli. Prevalence of 6 categories of diarrhoeagenic E. coli was determined by Multiplex Polymerase Chain Reaction (mPCR) using standard primers for their virulence genes. The multiplex RT PCR assay also detected 45 samples that tested positive for diarrheaogenic E. coli. Out of the 45 positive samples, 14 samples (26.7 %) were positive for Enterohemorrhagic E. coli (EHEC), 3 (6.7 %) were positive for Enteroinvasive E. coli (EIEC), 2 (4.4 %) were positive for Enteropathogenic E. coli (EPEC), 3 (6.7 %) were positive for Enterotoxigenic E. coli (ETEC) and 4 (8.9 %) were positive for Enteroagreggasive E. coli (EAEC). The remaining 19 (42.2 %) samples contained a mixture of two or more diarrheaogenic E. coli virulence genes. The presence of diarrhoeagenic E. coli in informal diary suggests that the consumption of the informal dairy products tested in this study could be a public health risk. Since E. coli is an indicator of poor hygiene in foods the study recommends food hygiene training for stakeholders and development of hygienic standard operating procedures for use by all stakeholders in the informal milk value chain to prevent or reduce consumer exposure to diarrhoeagenic E. coli through consumption of informal dairy products.Item Simulation of Groundwater Flow in the Voltaian (Around Tamale) Using Carbon-14(University of Ghana, 2013-07) Nti-Agyemang, I.; Akiti, T.T.; Adomako, D.; University of Ghana, College of Basic and Applied Sciences, School of Engineering, Department of Computer EngineeringStudying the process of groundwater flow in subsurface systems using numerical simulation has been widely practiced. The purpose of this study was to establish a 2D groundwater flow model for evaluating groundwater resources of the Voltaian Basin (around Tamale) in the Northern Region of Ghana. To understand the rate of abstraction of groundwater in the study area, a finite-element, steady-state groundwater flow model was used to simulate groundwater flow in the aquifer. COMSOL Multiphysics’ (FEMLAB) Earth Science Module (ESM) package which is finite element analysis and solver software was used. The radioisotope used in the study was Carbon-14. Three wells were sampled for Carbon-14 concentration and used for the model verification, based on elevation. From the results, groundwater in the study area moves generally from higher to lower hydraulic head along paths perpendicular to the equipotential lines. The groundwater flow paths in the aquifer in the study area indicated that flow is predominantly regional. There was a regional groundwater flow from Kanshegu to Nawuni. Kanshegu appears to be recharge area and Nawuni as discharge area. The flow rate obtained using Carbon-14 date was 2.86×10-7 m/s. The overall flow rate obtained from the model simulations was 2.66×10-7 m/s with an error margin of 6%.Item Total coliforms, arsenic and cadmium exposure through drinking water in the Western Region of Ghana: application of multivariate statistical technique to groundwater quality(Environmental Monitoring and Assessment, 2015-02) Affum, A.O.; Osae, S.D.; Nyarko, B.J.B.; Afful, S.; Fianko, J.R.; Akiti, T.T.; Adomako, D.; Acquaah, S.O.; Dorleku, M.; Antoh, E.; Barnes, F.; Affum, E.A.In recent times, surface water resource in the Western Region of Ghana has been found to be inadequate in supply and polluted by various anthropogenic activities. As a result of these problems, the demand for groundwater by the human populations in the peri-urban communities for domestic, municipal and irrigation purposes has increased without prior knowledge of its water quality. Water samples were collected from 14 public hand-dug wells during the rainy season in 2013 and investigated for total coliforms, Escherichia coli, mercury (Hg), arsenic (As), cadmium (Cd) and physicochemical parameters. Multivariate statistical analysis of the dataset and a linear stoichiometric plot of major ions were applied to group the water samples and to identify the main factors and sources of contamination. Hierarchal cluster analysis revealed four clusters from the hydrochemical variables (R-mode) and three clusters in the case of water samples (Q-mode) after z score standardization. Principal component analysis after a varimax rotation of the dataset indicated that the four factors extracted explained 93.3 % of the total variance, which highlighted salinity, toxic elements and hardness pollution as the dominant factors affecting groundwater quality. Cation exchange, mineral dissolution and silicate weathering influenced groundwater quality. The ranking order of major ions was Na+ > Ca2+ > K+ > Mg2+ and Cl− > SO4 2− > HCO3 −. Based on piper plot and the hydrogeology of the study area, sodium chloride (86 %), sodium hydrogen carbonate and sodium carbonate (14 %) water types were identified. Although E. coli were absent in the water samples, 36 % of the wells contained total coliforms (Enterobacter species) which exceeded the WHO guidelines limit of zero colony-forming unit (CFU)/100 mL of drinking water. With the exception of Hg, the concentration of As and Cd in 79 and 43 % of the water samples exceeded the WHO guideline limits of 10 and 3 μg/L for drinking water, respectively. Reported values in some areas in Nigeria, Malaysia and USA indicated that the maximum concentration of Cd was low and As was high in this study. Health risk assessment of Cd, As and Hg based on average daily dose, hazard quotient and cancer risk was determined. In conclusion, multiple natural processes and anthropogenic activities from non-point sources contributed significantly to groundwater salinization, hardness, toxic element and microbiological contamination of the study area. The outcome of this study can be used as a baseline data to prioritize areas for future sustainable development of public wells. © 2015, Springer International Publishing Switzerland.Item Tracking nitrate sources in groundwater and associated health risk for rural communities in the White Volta River basin of Ghana using isotopic approach (δ 15 N, δ 18 O[sbnd]NO 3 and 3 H)(Science of the Total Environment, 2017-12) Anornu, G.; Gibrilla, A.; Adomako, D.In this study, we present a first attempt on the use of integrated hydro-chemical and isotopic technique to trace the sources of groundwater nitrate contamination in the Upper East Region of Ghana to aid the sustainable management of this vital resource. The objectives of the study are (1) assess the present status and spatial distribution of the nitrate contamination (2) identify and distinguish the most likely sources of nitrate , (3) identify the relationship between 3H and NO3- and F-, and (4) ascertain the potential human risk from exposure to nitrate contamination. The results showed that, nitrate concentrations varied from 0.42 to 431.17, 0.83 to 143.94, 0.03 to 28.94mg/l with mean values of 36.09, 21.54 and 5.01mg/l for boreholes, hand dug wells and the surface water respectively. These values showed that, about 95% of boreholes and hand dug wells and 45% of the surface water have nitrate concentration above the baseline value in the area. The NO3-/Cl- ratio showed that, 98.4%, 95% and 64% of the NO3- in the borehole, hand dug wells and the surface water are from anthropogenic activities. The δ15NNO3 and δ18ONO3- data confirmed that NO3- in the samples was predominantly derived from manure (human and animal waste) and denitrification occurring in some areas. The isotopic data further affirms the hydro-chemical interpretation that, chemical fertilizer and atmospheric deposition are unlikely sources of NO3- in the area. The relationship between 3H and NO3- concentrations showed that, higher NO3- values are associated with younger waters. Non carcinogenic health risk for adults and children posed by oral ingestion of the NO3- contaminated water revealed some degree of health risk, especially to children whose risk is about 72% higher. The study provides a conceptual model of the NO3- dynamics and some recommendation for groundwater management in the area.