Kwasi Preko - Academia.edu (original) (raw)

Papers by Kwasi Preko

Heliyon

The Pra river catchment in Ghana is adversely affected by perennial flooding from high-intensity ... more The Pra river catchment in Ghana is adversely affected by perennial flooding from high-intensity rainfall events. To aid in flood management at the catchment, the Gumbel extreme value distribution has been used to estimate the return periods of maxima rainfall, flood, and consecutive dry and wet days (CDD and CWD) for a period of 5 to 100 years. The results revealed an expected increase in maxima rainfall, CDD and CWD. Maxima rainfall favours the south of the catchment while the CDD decreases northward. Furthermore, an increase in the magnitude of CWD observed at the centre of the catchment had a maximum of approximately 30 days for the 100 year return period, while lower flood volumes had a higher recurrence of 50% to 100% for 1 to 2 year return periods. The inclusion of a projected increase in anthropogenic activities and climate factors at the catchment will slightly affect the magnitude of these variables for the various return periods. Nonetheless, the findings in this study will be of essential input to policy implementation of the Integrated Water Resource Management Plan for river catchments in Ghana, West Africa.

This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge... more This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge data from the Ghana Meteorological Agency (GMet) over the period of 1970-2012. The onset and cessation dates were determined from cumulative curves using the number of rainy days and rainfall amount. In addition, the inter-annual variability of the onset and cessation dates for each climatic zone was assessed using wavelet analysis. A clear distinction between the rainfall characteristics and the length of the rainy season in the various climatic zones is discussed. The forest and coastal zones in the south had their rainfall onset from the second and third dekads of March. The onset dates of the transition zone were from the second dekad of March to the third dekad of April. Late onset, which starts from the second dekad of April to the first dekad of May, was associated with the savannah zone. The rainfall cessation dates in the forest zone were in the third dekad of October to the first dekad of November, and the length of the rainy season was within 225-240 days. The cessation dates of the coastal zone were within the second and third dekad of October, and the length of rainy season was within 210-220 days. Furthermore, the transition zone had cessation dates in the second to third dekad of October, and the length of the rainy season was within 170-225 days. Lastly, the savannah zone had cessation dates within the third dekad of September to the first dekad of October, and the length of rainy season was within 140-180 days. The bias in the rainfall onset, cessation and length of the rainy season was less than 10 days across the entire country, and the root mean square error (RMSE) was in the range of 5-25 days. These findings demonstrate that the onset derived from the cumulative rainfall amount and the rainy days are in consistent agreement. The wavelet power spectrum and its significant peaks showed evidence of variability in the rainfall onset and cessation dates across the country. The coastal and forest zones showed 2-8-and 2-4-year band variability in the onsets and cessations, whereas the onset and cessation variability of the transition and savannah zones were within 2-4 and 4-8 years. This result has adverse effects on rain-fed agricultural practices, disease control, water resource management, socioeconomic activities and food security in Ghana.

Magnetic susceptibility measurements and chemical analysis were performed on samples of water tak... more Magnetic susceptibility measurements and chemical analysis were performed on samples of water taken from the academic and residential areas of the Kwame Nkrumah University of Science and Technology (KNUST) campus, Kumasi. The aim of these measurements was to see if water delivered through metallic pipes was clean. Magnetic susceptibility measurements were performed using the Bartington MS2 magnetic susceptibility meter, with MS2G single frequency sensor and the chemical analysis was performed with the Varian SpectrAA 220FS Atomic Absorption Spectrometer. Results of the measurements showed that the water samples had negative magnetic susceptibility (χ) values of the order of 10 –5 and were thus diamagnetic. The χ values obtained for the samples were between –1.3  10 -6 SI and –1.23  10 -5 SI for the Academic Area (sampled colleges) and –3.0  10 -7 SI and –8.7 10 -6 SI for the Residential Area (sampled Halls of residence). Chemical analysis of the samples showed variation in the c...

International Journal of Scientific & Technology Research, 2016

Electromagnetic and electrical resistivity geophysical methods, were used to map out potential gr... more Electromagnetic and electrical resistivity geophysical methods, were used to map out potential groundwater sites for boreholes drilling in the Adoe community in the Sunyani west district of Ghana. The electromagnetic data was taken with the Geonics EM-34 conductivity meter while the electrical resistivity data was taken with the ABEM SAS 1000 C Terrameter using the Schlumberger electrode configuration. Results from the measurements revealed four subsurface geological layers of the following resistivity and thickness ranges: quartzitic sandstone with clay (42-118 Ωm, 12.2 m); sandy clay with silt (27-487 Ωm, 9-12 m); lateritic sandstone (13-728 Ωm, 6-14 m); and clayey shale (20-29 Ωm, 6-14 m), The overburden ranged in thickness from 14 m to 24 m. Sites selected for borehole drilling had a groundwater yield range of 0.94 -12 m 3 /h.

Remote Sensing Letters, 2016

ABSTRACT The study estimates planetary boundary layer height (PBLH) using temperature and humidit... more ABSTRACT The study estimates planetary boundary layer height (PBLH) using temperature and humidity profiles from Cross-Track Infrared Sounder (CrIS) onboard Suomi National Polar-Orbiting Operational Environmental Satellite System Preparatory Project (SNPP). PBLH is estimated using six different methods and also using an integrated approach. PBLH estimated from SNNP-CrIS soundings by the integrated approach is compared with the PBLH values estimated using atmospheric profiles from radiosonde ascents and Constellation Observing System for Meteorology Ionosphere and Climate-radio occultation (COSMIC-RO) measurements. Analysis shows reasonable agreement of PBLH values from SNPP-CrIS soundings with those from radiosonde measurements and COSMIC-RO retrievals, thus revealing the capability of atmospheric profiles from SNNP-CrIS for the characterization of planetary boundary layer (PBL) with excellent spatial resolution and coverage. PBLH from SNNP-CrIS soundings are observed to be overestimated by around 336 m compared to the estimates from radiosonde ascends and is partly attributed to the difference in time of observations and coarse vertical resolution of the SNPP-CrIS-derived profiles. Compared to the estimates from SNPP-CrIS soundings, PBLH values from COSMIC-RO profiles are overestimated by around 596 m. Estimates from SNPP-CrIS soundings, through the integrated approach, are further used to examine the spatial and seasonal variations of PBLH over the Indian landmass. PBLH is observed highest in pre-monsoon and lowest in winter over most of the regions. Due to rainfall and associated changes in lower atmosphere and surface characteristics, PBLH is observed shallow during monsoon.

African Journal of Environmental Science and Technology, 2016

This research work presents a study on the application of magnetic susceptibility measurements an... more This research work presents a study on the application of magnetic susceptibility measurements and geochemical analysis for mapping or assessing heavy metal pollution in the agricultural soil in road proximity. The research work was also done to check any runoff of heavy metals pollution to the Owabi dam which serves as the main water sources to catchment areas and the whole of Kumasi Metropolis. This research work was conducted along the asphalt road closed to Amamfrom Community in the southern part of Ghana. The study revealed that magnetic susceptibility measurements can be used as a proxy and fastest method of determining heavy metal pollution in agricultural soils. The results showed three most important trends: 1) the samples collected near the road have higher values of magnetic susceptibility and mean heavy metals content than those collected far from the road exhaust; 2) some of the sample areas undisturbed by erosion and weathering have significant magnetic susceptibility and heavy metals contents; 3) some of the sample areas washed away by erosion are believed to be deposited in Owabi Dam due to their low ground reliefs. Therefore, future research should concentrate on Owabi Dam which may be polluted by the runoff from these heavy metals.

This paper documents the extent of trace metal pollution in surface soils at the “Suame-Magazine”... more This paper documents the extent of trace metal pollution in surface soils at the “Suame-Magazine” industrial area of Kumasi, and evaluates potential for associated industrial impacts. Concentrations of Pb, Cu, Ni, Hg, and As were estimated by ED-X-ray Fluorescence (XRF) analysis. Sampling sites were selected from areas reflecting a gradient of industrial activity. Surface soils (0-15cm) were collected and analysed. Mean concentration values of Pb, Cu, Ni, Hg, and As respectively ranged from, 133.7- 571.3 mgkg-1, 62.9 - 334.6 mgkg-1, 12.4 - 30.9 mgkg-1, 5.5 - 10.4 mgkg-1 and 2.3 - 18.6 mgkg-1. Apart from Ni and As, all the trace metals exceeded respective threshold limit values (TLVs). Spatially, the distribution of metals demonstrates significant correlations along a gradient of industrial activity. Findings are of sufficient concern to warrant additional investigation and risk assessment.

Soil and Sediment Contamination: An International Journal, 2012

Knowledge of soil heavy metal concentration is very important for assessing the purity and qualit... more Knowledge of soil heavy metal concentration is very important for assessing the purity and quality of the soil in an environment. The concentrations of nine heavy metals (NHM), Zn, Pb, Cr, Cu, Co, Ni, Cd, Hg, and As from the near-surface soils (∼ 0–15 cm) from an industrial cluster in Kumasi, Ghana were qualitatively and quantitatively measured and analyzed using X-ray

European Journal of Physical Sciences

Objective: To explore the implementation of an incident learning system for quality management of... more Objective: To explore the implementation of an incident learning system for quality management of radiotherapy in a low-income radiotherapy setting. Materials and Methods: An incident learning system was specifically designed using the human-centred design, the waterfall model was implemented for error identification and learning of individual incidents. The incidents that occurred in external beam radiotherapy for 8 years, were reported. Results and Discussion: A total of 122 incidents, 49 Near-misses and 28 non-conformance were identified with 4465 patients treated within the 8 years. The total average percentage of 2.73, 1.10, 0.63 and 4.46 were detected for incidents, near miss and non-conformance respectively. The average incident, near miss and non-conformance rate per 100 patients treated were 2.73, 1.10 and 0.63 respectively over the 8-years review period. The highest wrong total dose error of 79 occurred in the eighth year. Trend analysis identifies major improvements in cl...

Applied and Environmental Soil Science

Soil infiltration at a watershed scale is important for understanding and predicting the hydrolog... more Soil infiltration at a watershed scale is important for understanding and predicting the hydrological process in soil-water-plant systems. This study investigated the effects of land use (LU) conversion on the infiltration rate in the Ouriyori watershed. To that end, in situ infiltration was carried out over the watershed under thirty-six pairs of adjacent cropland-fallow plots using the hood infiltrometer. Saturated hydraulic conductivity (Ks), soil properties, and soil classes were further compared. Results showed a high variability of Ks following the LU classes with a coefficient of variation greater than 60%. After data log transformation, the mean values of Ks showed high infiltration and ranged between 2.59 and 2.42 cm d−1, respectively, for fallow land and cropland. Thus, Ks was relatively lower in cropland compared to fallow land. Hence, the low infiltration recorded in croplands indicated the degradative impacts of unceasing tillage operations for crop production without c...

This study employs the GIS-Based DRASTIC model to evaluate vulnerability of groundwater to contam... more This study employs the GIS-Based DRASTIC model to evaluate vulnerability of groundwater to contamination of the Greater-Accra Region of Ghana. It therefore synthesizes both a computer-based GIS and the DRASTIC to demonstrate an effective method for groundwater contamination and aquifer vulnerability assessment. In Ghana, groundwater is predominantly used as a domestic water-supply (including drinking), irrigation and purposes of industrial consumption. Therefore, assessing the vulnerability to delineate aquifers that are more susceptible to contamination is very significant. The model is considered to have a significant control and potential of affecting groundwater contamination in general, and it consists of seven (7) major hydrogeological parameters (Depth to groundwater-D, net Recharge-R, Aquifer media-A, Soil media-S, Topography-T, Impact of vadose zone-I, and hydraulic Conductivity-C) combined to form its acronym "DRASTIC". A vulnerability map was therefore obtained ...

Free Radical Biology and Medicine, 2021

Gamma irradiation, mimicking oxidative stress, triggers neutrophil priming  In the absence of an... more Gamma irradiation, mimicking oxidative stress, triggers neutrophil priming  In the absence of any other stimulation, irradiated neutrophils generate moderate amount of ROS through the activation of NADPH oxidase  ROS production is due to incomplete assembly of the NADPH oxidase complex at the plasma membrane of irradiated neutrophils  A priming marker was identified on p47 (phosphorylation of Ser345)  Pre-stimulated neutrophils by irradiation respond with increased oxidative burst

Abstract- Magnetic susceptibility measurements and chemical analysis were performed on samples of... more Abstract- Magnetic susceptibility measurements and chemical analysis were performed on samples of water taken from the academic and residential areas of the Kwame Nkrumah University of Science and Technology (KNUST) campus, Kumasi. The aim of these measurements was to see if water delivered through metallic pipes was clean. Magnetic susceptibility measurements were performed using the Bartington MS2 magnetic susceptibility meter, with MS2G single frequency sensor and the chemical analysis was performed with the Varian SpectrAA 220FS Atomic Absorption Spectrometer. Results of the measurements showed that the water samples had negative magnetic susceptibility (χ) values of the order of 10 –5 and were thus diamagnetic. The χ values obtained for the samples were between –1.3 � 10-6 SI and –1.23 � 10-5 SI for the Academic Area (sampled colleges) and –3.0 � 10-7 SI and –8.7 � 10-6 SI for the Residential Area (sampled Halls of residence). Chemical analysis of the samples showed variation i...

Aeromagnetic and radiometric methods were used to investigate the Konongo area located at the nor... more Aeromagnetic and radiometric methods were used to investigate the Konongo area located at the northeastern boundary of the prospective Ashanti Gold Belt in south-eastern Ghana. Datasets from these aerogeophysical methods proved vital for mapping geology and structure. The application of magnetic image enhancing techniques such as reduction to pole, analytical signal and first vertical derivative in processing the datasets helped in the delineation of folds, fractures, lithological boundaries and the two main Birimian tectonic structural deformation events D1 (NE-SW) / D2 (NNW-SSE) which are potential hydrothermal gold mineralization zones within the area. The contacts between Birimian metasedimentary and meta-volcanic rocks noted to host gold mineralization in the belt were also delineated. The radiometric datasets retrieving geochemical information on potassium (K), thorium (Th) and uranium (U) concentrations within the study area were used to delineate bedrock lithology of the Ban...

Monitoring of soil water content (volumetric water content, VWC) is an important process in agric... more Monitoring of soil water content (volumetric water content, VWC) is an important process in agricultural and ecological programs, and a vital process in flood and water resource management. There are several methods in estimating VWC but often these are time consuming, invasive and expensive. This paper investigates the applicability of a surface based geophysical technique, Ground-Penetrating Radar (GPR), for estimating the VWC in shallow soil (top 0.30 m of soil subsurface). The guided wave sounding, GWS, technique (an invasive application of the GPR technique) was used on a vegetable garden located at latitude 6.67 and longitude -1.56, south of the College of Engineering, KNUST, Kumasi, Ghana. The MALA ProEx GPR equipment using shielded antennae with a central frequency of 800 MHz was used for the measurements. The result showed that, on the average, the VWC at the top soil (0.065 m) containing humus was high (0.12 m 3 m -3 ) as compared to depth 0.295 m (0.10 m 3 m -3 ). Thus, t...

Article published in Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS),2012.

Atmosphere, 2020

In regions of sparse gauge networks, satellite rainfall products are mostly used as surrogate mea... more In regions of sparse gauge networks, satellite rainfall products are mostly used as surrogate measurements for various rainfall impact studies. Their potential to complement rain gauge measurements is influenced by the uncertainties associated with them. This study evaluates the performance of satellites and merged rainfall products over Ghana in order to provide information on the consistency and reliability of such products. Satellite products were validated with gridded rain gauge data from the Ghana Meteorological Agency (GMet) on various time scales. It was observed that the performance of the products in the country are mostly scale and location dependent. In addition, most of the products showed relatively good skills on the seasonal scale (r > 0.90) rather than the annual, and, after removal of seasonality from the datasets, except ARC2 that had larger biases in most cases. Again, all products captured the onsets, cessations, and spells countrywide and in the four agro-ec...

Hydrological Sciences Journal, 2020

ABSTRACT Freshwater supply remains limited in West Africa due to lack of operational governance f... more ABSTRACT Freshwater supply remains limited in West Africa due to lack of operational governance frameworks. In this study, the Water flow and balance Simulation Model (WaSiM) and the Soil and Water Assessment Tool (SWAT) were applied in the Ouriyori catchment (14.5 km2, Benin) to assess hydrological ecosystem services (HES) in terms of service flow and service capacity using the ecosystem accounting framework. The modelling exercises indicated satisfactory goodness-of-fit coefficients greater than 75% with an absolute bias of less than 25%. The HES capacity was in general higher than the HES flow for crop and household (surface/groundwater) water supplies, indicating that the catchment can potentially supply more water under optimal storage and management conditions. Positive and negative shifts in service capacities of crop water and household supplies were observed over the simulation period. These significant results can support sustainable interventions in securing water and food productions through increasing HES flow and capacity.