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Assessment of microbiological and physicochemical quality of wastewater used for vegetable irrigation along the old waterworks stream in Tamale metropolis of Ghana
(KNUST, 2018-06) Bashiru Nuhu, Rabi
Worldwide, several million hectares of farmland in estimated 50 countries are used to cultivate agricultural produce by farmers who have adopted the application of untreated and or partially treated wastewater from various sources. The application of untreated wastewater which are contaminated with microbes and chemicals including heavy metals poses serious public health threat on the vegetable farmers, vendors and consumers of vegetables cultivated using such untreated wastewater. This study assessed the microbiological, physical and chemical qualities of wastewater used for vegetable irrigation along the Tamale old waterworks stream in the Tamale Metropolis of Ghana. Two wastewater samples each were collected from the four sampling sites: Waterworks upstream (WWU), Gumbihini midstream (GMS), Nyanshagu midstream Gardens (NMS) and Tunayili Kulbong Downstream Gradens (TKDS) along the stream monthly for six consecutive months for microbial and physicochemical parameters for dry and rainy seasons. A total of forty-eight water samples were collected and analysed for their microbiological, chemical and physical qualities using standard protocols adopted by the American Public Health Association (APHA, 1998). The results obtained showed consistent increase in the bacterial and physicochemical load for both irrigation seasons. The bacterial parameters studied include total coliform, faecal coliform, E. coli, Staphylococci, Enterococci, Pseudomonas and total heterotrophic bacteria. The statistical analysis on the microbials gave a weak correlation (r=0.24) among the individual sampling sites for microbial statistics. More so, there is a significant difference between the wastewater samples for dry and rainy season irrigation of microbial parameters with (p = 0.005) from the pairwise sample test. Results obtained showed consistent increase in the bacteria load for both seasons with the rainy season recording higher loads than the dry season except for total heterotrophic bacteria which was rather higher in the dry season as compared to rainy season. Overall, bacterial count recorded was lowest at GMS1 and highest at NMS2 for both seasons. The physicochemical parameters include, pH, conductivity, total alkalinity, total hardness, calcium hardness, magnesium hardness, carbonate hardness, bicarbonate hardness, calcium, magnesium, chloride, fluoride, sulphate, sulphide, phosphate, ammonia-nitrogen, nitrate-nitrogen, nitrite-nitrogen, aluminium, total iron, manganese, copper, zinc, cyanide, total chromium and potassium. There is strong correlation (r=0.99) among the individual sampling sites for physicochemical parameter analysis of wastewater samples during dry and rainy season irrigation schemes. More so, pairwise analysis indicates that there is no significant difference (p= 0.41) among the sampling sites for physicochemical wastewater samples for dry and rainy season irrigation of physicochemical parameters. Overall, physicochemical values recorded were lowest at GMS1 and highest at NMS2 for both the dry and rainy season samples. More so, bacterial counts recorded for all the microbial parameters exceeded the WHO (2006b) guideline of 1x103cfu/100ml for unrestricted irrigation of crops likely to be eaten raw whilst the physicochemical parameters determined were found to be within FAO/WHO guidelines for irrigation water except for colour, total alkalinity, chloride, zinc and cyanide. Most of the chemicals had levels above WHO guidelines and are potential health threat especially high nitrate concentration in irrigation water causes blue baby syndrome. The application of untreated wastewater poses serious public health threat on the vegetable farmers, vendors and consumers of vegetables cultivated using such untreated wastewater. It is therefore recommended that wastewater for irrigation of ready-to-eat vegetables be treated using biological nutrient removal system and wastewater stabilisation ponds to reduce and or eliminate contaminants before irrigating vegetables.
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The scalability metric, based on cost-effectiveness in distributed systems using fundamental laws
(KNUST, 2018) Gyasi Emmanuel Kwabena
Today’s computer systems are more complex, more rapidly evolving, and more essential to the conduct of business than those of recent past. The complexity becomes more rigid in the case of distributed systems. A distributed system is a collection of independent computers that appear to its users as a single coherent system. A distributed system should be deployable in a wide range of scales, in terms of numbers of users and services, quantities of data stored and manipulated, rates of processing, numbers of nodes, geographical coverage, and sizes of networks and storage devices. The derived scalability metric of this thesis is based on cost effectiveness, in which the effectiveness is a function of the system's throughput and its Quality of Service. It is a strategy based scalability metric that generalizes the well -known metrics for scalability of parallel computations to describe heterogeneous distributed systems. Scalability is measured by the range of scale factors that gives a satisfactory value of the metric, since a good scalability is a joint property of the initial design and the scaling strategy. What makes this derived metric unique is the fact that, it separates the impact of throughput and response time on the metric, formalizing the notation of a scaling strategy, introducing QoS evaluation and more also, introducing formal scalability enablers which are optimized at each scale factor. Throughput curves for all systems with bottleneck demand 𝐷𝑚𝑎𝑥 are constrained to lie below the line 1𝐷𝑚𝑎𝑥⁄. If one needs to improve the performance further than this limit, then it is necessary to reduce the demand at the bottleneck center somehow.
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Pricing critical illness insurance using the dash and grimshaw model
(KNUST, 2018-06) Asabre, Ebenezer
Critical Illness Insurance is a new product and its now gaining grounds on the Ghanaian insurance industry market. This research is aimed at developing a fair pricing system for a critical illness insurance using the Dash and Grimshaw model which has embedded multi-state(decrement) model. Due to the uncertainty in the future and the possibility of an individual being diagnosed of some critical illness, it is important to cover oneself against this possible adverse financial trauma. This research considered five critical illnesses thus cancer, heart attack, stroke, kidney failure and Coronary Artery Bypass Graft. Data on the incidence rates for all the critical illnesses was used to compute the stand alone rates, acceleration rider benefit rates and premium rate from ages 20 to 80 inclusive using the Dash and Grimshaw model. Results from my computations showed that incidence rates and its corresponding premium rates are directly proportional to one’s age. Also the difference in stand-alone and accelerated rates was directly proportional to one’s age.
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Dilemmas in model selection in time series analysis
(KNUST, 2018-06) Arthur, Doris
This study seeks to resolve two important dilemmas in model selection in time series analysis. These are to compare the performance of the graphical and the information criterion methods in selecting the true model. In addition, Yu et al. (2005) relative precision performance stability was modi_ed. For the graphical and information criterion comparison, dataset from ARIMA models were simulated. Also the cocoa production and rainfall datasets in Ghana were used to validate the modified relative precision performance stability of Yu et al. (2005). It was observed from the study that, in comparison to the performance of the graphical method and the Akaike information criterion (AIC) in selecting the ARIMA models, the information criterion performs better than the graphical method. Also, in verifying for the size of the evaluation sets in forecasting, whether to select a single model or combine the models of di_erent models, our findings showed that the size of the evaluation sets may not influence the decision of selecting or combining since 97% of the decisions were to combine the models. In addition to that, though there was a modification on the computations of the relative prediction performance stability formerly utilized by [Yu et al., 2005], the decision rule still remains the same. Hence, whether the use of the mean or median on different the size of evaluation sets and interval, the combining strategy still outperforms.
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Analysis of metal content of seized cocaine in Ghana
(KNUST, 2018-11) Bentil, Edward
The trafficking of cocaine has become a global challenge now and Ghana is no exception. Cocaine is a whitish powder, which is, produced both from natural and synthetic means. The aim of the project was to study the metal content of seized cocaine in Ghana and the data used for batch identification. Ten metals namely Pb, Cu, Mg, Mn, Cr, As, Ni, Fe, Co and Ca were analyzed in 37 cocaine samples which were sampled from seizures made from 2010 to 2014 and samples selected based on within-seizure and between-seizure classifications. Seized cocaine samples were obtained from Ghana Standards Authority by the help of Narcotic Control Board of Ghana. All seized illicit cocaine samples used were classified under natural cocaine. Analyses of the metals were done using ICP-MS and data analysis done using ANOVA at 95% confidence level. The results showed that, Calcium recorded the highest amount in all the samples with a mean ppm value of 64.94±54.60 with Magnesium, Zinc and Iron recording moderate amounts. All the samples analyzed contained Calcium since lime is known to be used as one of the additives in the production of cocaine. All the cocaine samples, which were sampled, based on within-seizure classification under class A showed no significant differences between each pair. With three sample pairs under class B in the within-seizure classification, one of the pairs, 103A and 105B showed no significant differences between them even though they were sampled from two different packages from the same seizure. Five samples from five different seizures also showed significant difference among them showing that they came from different batches or origin. It could be confirmed that seized cocaine contained some poisonous heavy metals like Lead, Arsenic and Chromium, which had amount that could affect the user. Based on the data gathered from the within-seizure class A group, it could be proposed that a missing cocaine could be identified by its metal content if no adulterants were added during the time it could not be found. With the information on the metal content of cocaine, the identity of seized cocaine can be achieved with the purity during forensic screening in order to protect the cocaine during investigations.
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Changes in land use and land cover and cocoa production in relation to gold mining in the Amansie West district, Ghana
(KNUST, 2018-11) Blankson, Anastasia Comfort
Artisanal and small-scale gold mining can greatly impact cocoa production by reducing land cover, labour force and the quantity of cocoa produced, yet these effects have been scarcely studied. This study examined the effects of land use/land cover change as a result of artisanal and small-scale gold mining on cocoa production from 1997 to 2016 in the Amansie West District, Ghana, using both quantitative and qualitative methods. Google Earth, Landsat images and Geographical Information System (GIS) were used to estimate and map land use/land cover changes over the period. Purposive and double-staged cluster sampling methods were used to obtain information on the subject matter from three relevant institutions and 434 cocoa farmers, respectively, in the district. The t-test was used to evaluate the differences in cocoa production between the periods 1997 to 2006 and 2007 to 2016, whereas the Pearson correlation was used to assess the relationship between the farm size and cocoa harvested over the same period. Change matrices for the periods 1986 to 2007 and 2007 to 2016 were used to ascertain the extent to which artisanal gold mining had taken over cocoa land cover. Results indicated a significant decrease in cocoa production over the period 2007 to 2016 compared to the period 1997 to 2006. There was also a statistically significant positive correlation between the extent of farms size and cocoa produced over both. The extent of land cover of cocoa farms accounted for 10 % variance in cocoa production. Subsequently the maps showed that the land cover of cocoa increased by 13% from 1986 to 2007 while in 2016 there was a 1.8 % increase in land cover. Artisanal and small-scale gold mining on the other hand experienced an increase of 124% in land cover from 1986 to 2007, and again, a dramatic increase of 12442% increase in 2016. The change matrices for both 1986 to 2007 and 2007 to 2016 showed that land converted to artisanal mining sites were covered mostly by cocoa farms. These outcomes reflected a direct linkage between the extent of land use and land cover changes due to artisanal and small-scale gold mining and cocoa production which can be effectively addressed if the plight of the cocoa farmer is made the prime focus.
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Assessment of formaldehyde levels in some selected offices, Residential homes and mortuaries in Ashanti region
(KNUST, 2018-05) Boakye-Agyemang, Desmond
Formaldehyde is the main ingredient in embalming liquids used in mortuaries for preserving bodies. Pressed wood products, carpets, cleaning products such as detergents and disinfectants, and furniture are significant sources of formaldehyde in residential homes and offices. Due to formaldehyde’s carcinogenicity, it has brought into question the impact of indoor air pollutants and indoor air quality. This poses health risk to the workers and residents in these facilities. This study measures the formaldehyde levels both indoor and outdoor at some selected offices, homes and mortuaries. Air samples were taken from the various offices and rooms in mortuaries and homes and analysed using the MBTH method. Temperature and relative humidity were also measured and a survey on the potential formaldehyde sources in these areas and health effects were administered to respondents at the same time. Formaldehyde levels recorded for homes ranged between 20 and 430 μg/m3. At a significant level of 0.05 (5%), no significant difference were found between the mean concentrations of formaldehyde in bedrooms and halls. Significant positive correlations (p<0.05) were found between temperatures and the formaldehyde concentrations in the kitchens, bedrooms, and living rooms. The type of fuel used in these kitchens for cooking showed a positive correlation of 0.011 (p< 0.05) with the level of formaldehyde concentration. Indoor formaldehyde concentration recorded for homes ranged between 60 and 430 μg/m3 which exceeds the World Health Organization’s recommended permissible limit of 100 μg/m3 for homes. The concentrations of formaldehyde recorded for the sampled air from offices ranged between 45 and 399 μg/m3. Similarly a positive correlation (p<0.05) between relative humidity, temperature and concentrations of formaldehyde was observed. The levels of formaldehyde level recorded for mortuaries in this study ranged between 14 and 710 μg/m3. This level is higher than the limit set by American Conference of Governmental Industrial Hygienists’ (ACGIH) Time Weighted Average (TWA). Temperature and relative humidity was positively correlated with the level of formaldehyde concentration (p=0.003). Analysis of the survey showed that the health effect that was complained frequently by residents was headache. Similarly, some workers in offices complained of headaches. Workers in the mortuaries complained of symptoms such as eye irritations, skin irritation, nose and throat irritation, headaches and sometimes vomiting. These symptoms are related to specific place of activity within the facility and how frequent a particular worker visits or comes to work weekly. The health effect that was complained frequently in homes from the questionnaire was headache. The correlation matrix analysis conducted in this study indicates that homes and offices that use cleaning products such as detergents and disinfectants recorded high levels of formaldehyde. The hazard quotient (HQ) values calculated ranged from 0.1 - 5.2. About 50.68 % of the calculated HQ values were above the safety limit (HQ=1).