Browsing by Author "Affum, H.A."
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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 Evaluation of Heavy Metals Contamination of Soil and Vegetation in the Vicinity of a Cement Factory in the Volta Region, Ghana(International Journal of Science and Technology, 2012) Addo, M.A.; Darko, E.O.; Gordon, C.; Nyarko, B.J.B.; Gbadago, J.K.; Nyarko, E.; Affum, H.A.; Botwe, B.O.Heavy metal mobilization in the biosphere by human activities has become an important process in the geochemical recycling of these metals. In this work, 34 soil samples and 29 Tephrosia elegans plants collected in the vicinity of the Diamond Cement Factory, Aflao, Ghana were analyzed for As, Co, Cr, Cu, Mn, Ni, Pb and Zn using energy dispersive XRF. The results of the metal analysis indicated that some metallic levels were in excess of natural background and critical limits for the soil and plants respectively. The results further revealed that the metal distribution were in a fluctuating manner considering various distances and directions from the cement facility. However, it was observed that the mean metal concentrations of the soil and plants decrease as distance from the cement facility increased for most metals. This indicated that the facility which is the only industrial source in the area is the major cause of the pollutants contamination in its vicinity. In an attempt to understand the pattern of metal contamination in the area, useful tools including enrichment factor, geoaccumulation index and pollution load index were employed to indicate the sources of soil contamination were anthropogenic in character. Recommendations for the need for other studies on environmental and human health around the cement and similar facilities to protect human life and the environment are suggested.Item Performance of AERMOD and CALPUFF models on SO2 and NO2 emissions for future health risk assessment in Tema Metropolis(Human and Ecological Risk Assessment, 2018-03) Amoatey, P.; Omidvarborna, H.; Affum, H.A.; Baawain, M.AERMOD results were compared with the reported CALPUFF results to estimate the concentrations and temporal distributions of SO2 and NO2 from Tema Oil Refinery with particlar attention to heavy rainy season (HRS), minor rainy season (MRS), and dry season (DS). Statistical indices, including the fractional bias (FB), geometric mean variance (VG), normalized mean square error (NMSE), index of agreement (IOA), and geometric mean bias (MG), were used to assess the reliability of the models. Overall, AERMOD better predicted ambient SO2 and NO2 levels than the reported CALPUFF model. For SO2, AERMOD showed a good agreement with FB, IOA, and MG while CALPUFF showed a good prediction in NMSE and VG. Also, AERMOD predicted NO2 well with NMSE, IOA, MG, and VG compared with FB for CALPUFF. The MRS results showed higher hourly maximum concentrations (107.4 µg/m3 for SO2 and 31.7 µg/m3 for NO2). Maximum daily concentrations were slightly higher in HRS (37.7 µg/m3 for SO2 and 9.6 µg/m3 for NO2) compared to MRS and DS. The performace of the models may provide a better understanding for future epidemiological studies.Item Radiotracer investigation in an aerobic digester of a wastewater treatment plant(Applied Radiation and Isotopes, 2020-01-18) Dagadu, C.P.K.; Luabanya, J.S.M.; Affum, H.A.Radiotracer residence time distribution (RTD) methodology was used to determine the hydrodynamic parameters of the aerobic digester of an effluent treatment plant. Technicium-99m was used as a radiotracer. The concentration of radiotracer in the exit stream of the digester was determined using an on-line tracer monitoring method. The experimental mean residence time (MRT) of the digester was found to be 4 h, far less than the theoretical MRT calculated with respect to nominal flow parameters (volume and flow rate of material into the digester). The experimental MRT corresponds to a percentage effective volume of 11% translating into approximately 89% dead volume in the digester leading to the conclusion that the hydrodynamic performance of the aerobic digester of the effluent treatment plant was not efficient. A radioactive tracer (Tc-99m) was used to determine the flow type in the digester; an RTD Software was used to model the flow by curve fitting the experimental RTD with various non ideal flow models. It was observed from the radiotracer experiment that the perfect mixers in series with exchange model best described the flow type existing in the digester.