Browsing by Author "Carboo, D."

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Application of the QuEChERS procedure and LC–MS/MS for the assessment of neonicotinoid insecticide residues in cocoa beans and shells Journal of Food Composition and Analysis
(Elsevier - Journal of Food Composition and Analysis, 2015-09) Dankyi, E.; Carboo, D.; Gordon, C.; Fomsgaard, I.S.
The Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) procedure was applied and validated for the analysis of neonicotinoid insecticide residues in cocoa bean matrix with high fat and high pigments. Samples employed in the study were fermented and dried beans obtained from major cocoa producing regions in Ghana where neonicotinoids are extensively used. Shells covering the beans were removed and analyzed separately to examine insecticide distribution. Analytes in both matrices were extracted in acetonitrile with sodium acetate and magnesium sulfate salts, cleaned up using a sorbent mixture of primary secondary amine (PSA), C18 and graphitized carbon black (GCB), and quantified using liquid chromatography tandem mass spectrometry (LC–MS/MS). Average recoveries at four levels of fortification ranged from 92 to 111% with relative standard deviation of 16% for all analytes. Limits of quantification ranged from 3 to 10 mg/kg for all neonicotinoids. Imidacloprid was the most frequently encountered neonicotinoid and was quantified in more than 10% of deshelled bean and 30% of cocoa shell samples, with concentrations ranging from 11.5 to 35.6 mg/kg and 11.8 to 214 mg/kg in cocoa beans and shells, respectively. The findings from this study suggest a need for greater efficiency in neonicotinoid application, to avoid the build-up of these insecticides to unsafe levels in cocoa beans.
Assessing municipal solid wastes (MSW) for composting programs in rapidly urbanizing area: a case study from Accra, Ghana
(International Journal of Environment & Waste Management (IJEWM)1/2(6): 25-40, 2009) Attuquayefio, D.K.; Fobil, J.N.; Carboo, D.; Rodrigues, F.K.; Sory, S.
A complete understanding of all physico-chemical and biochemical attributes of waster stream materials is necessary for successful implementation of waste management programmes in a given context because of their influence on the behaviour of these materials in the natural environment. This paper discusses these properties of Municipal Solid Waster (MSW) to guage its suitability compositing programmes in Accra, a rapidly urbanizing city. The results showed that the MSW was very wet at 60% moisture content by weight. Additionally, the proportion of the biological originated carbon was considerably high compared with nitrogen thus giving high values of carbon to nitrogen (C:N) ratios (i.e., roughly 27:1-100:1). The percentage composition of materials ranged between 55-65% and 40-45% for compostable and combustible materials, respectively. In conclusion, the MSW in the metropolis could be a good candidate for successful compositing programmes if social and economic factors were conductive.
Assessment of heavy metal contamination and macro-nutrient content of compose for environmental pollution control in Ghana.
(Global Journal of Environmental Research 2(3): 133-139., 2008) Hogard, J.N.; Fobil, J.N.; Ofosu-Budu, G.K.; Carboo, D.; Ankrah, N.A.; Nyarko, A.
This study examined macro-nutrient content of solid waste compost to determine the potential of the compost for soil fertility amelioration in Ghana. Heavy metal concentrations in the compost were also examined to assess the potential health implication of compost application in urban and peri-urban agriculture. It was observed that the overall NPK concentration was low in the different compost types, but generally total N and K were greater in agricultural waste compost compared to municipal solid waste (MSW) composts. The agricultural waste compost was also richer in organic carbon. In terms of toxicity concerns, heavy metals concentration (Ni, Zn, Cu and Cd) were generally low in the different types of composts and within permissible, Australia standards for compost products. However, lead (Pb) concentration in mixed MSW composts was significantly high in the dry season, exceeding the Australian limit of 150 mg/kg Pb, required for unrestricted compost use. There was considerable seasonal variation in the heavy metal levels in the composts made from open windows process, with reduced levels in the rainy season. It appeared that seasons affected mixed waster characteristics, which affected compost quality. It was therefore concluded that seasons and composting processes, to some extent, were important determinants of the levels of toxic metal concentrations in final compost products in Ghana.
Assessment of Phthalates Migration in Polyethylene Food Packages: A Case Study in Ghana
(University of Ghana, 2015-07) Ayamba, A. A.; Carboo, D.; Kyeremeh, K.; University of Ghana, College of Basic and Applied Sciences, School of Physical and Mathematical Sciences, Department of Chemistry
The use of plastics such as polyethylene in the food industry in Ghana as opposed to traditional forms of packaging such as the use of leaves and paper is constantly growing with different designs and compositions. These plastics contain chemicals that are added during the manufacturing process. These chemicals, such as plasticizers, are used to make the plastics flexible but are not covalently bonded to the polymer, hence are able to migrate from the food packages into food when heated or stored for a long term. In this regard, plasticizers such as phthalates from food contact materials have raised many concerns due to suspected carcinogenic effects in humans. Other effects due to the exposure to phthalates include damage to liver, kidney, heart, and lungs as well as adverse effects on reproduction, development and blood clotting. Five different polyethylene packaging materials including: black polythene bags, plain polyethylene bags/films commonly called take away bags, polyethylene plastic bottles, thick plain polyethylene bags/films and polyethylene food containers were assessed. Total of four phthalates were soxhlet-extracted and identified by GC-MS. The extent of migration of the phthalates into food was assessed using food simulants (distilled water for aqueous food and olive oil for fatty foods) by varying exposure times and temperatures. The results indicated that the four phthalates under investigation were all detected in the polyethylene packaging materials. DBP was detected in all the polyethylene samples. DEHP was detected in 20 out of 25 polyethylene samples. The concentrations ranged from not detected to 14.30mg/kg for DEHP, 3.60mg/kg to 15.45mg/kg for DBP and not detected to 5.14mg/kg for DEP. BBP was detected in only one out of the 25 samples analysed with a concentration of 1.43mg/kg. The migrated phthalates from the polyethylene packaging materials into the aqueous food simulant were detected in trace concentrations with average values of 1.68μg/kg for DEHP, 0.60μg/kg for DBP and 0.01μg/kg for DEP. The migrations of these phthalates in the aqueous food simulant were all below the EU specification for phthalate migration in food contact materials. The migration of phthalates in the fatty food simulant however showed very high concentrations of phthalates migration from the polyethylene packaging materials into the olive oil. The migrated concentration of DEHP and DBP ranged from 0.69mg/kg to1.60mg/kg and not detected to 1.43mg/kg respectively. The rate of migration of phthalates from the polyethylene packaging materials into food simulant increased with increasing temperature in both food simulants. The results indicated that 28.13% and 34.38% of the migrated DEHP and DBP in the fatty food simulant exceeded the SML for food contact materials according to the EU regulation. Migrated BBP was however not detected in the fatty food simulant (olive oil).
Atmospheric burden of organochlorine pesticides in Ghana
(Chemosphere, 2014-05) Hogarh, J.N.; Seike, N.; Kobara, Y.; Ofosu-Budu, G.K.; Carboo, D.; Masunaga, S.
Organochlorine pesticides (OCPs) are subject to the Stockholm Convention on POPs and have been banned or restricted globally. In Ghana, concerns of illicit applications of some OCPs have been raised in recent times. Applying polyurethane foam (PUF) disk passive air samplers (PAS), the levels of OCPs in the atmosphere and their spatial resolution were investigated. It was the first nationwide coverage of OCPs monitoring in Ghana. ∑DDTs and endusulfans constituted the highest burden of atmospheric OCPs in Ghana, at average concentrations of 156±36 and 153±28pgm-3, respectively. Mirex had the lowest concentration (0.2±0.01pgm-3). From the chemical signatures of the various OCPs, we deduced that DDT, endosulfans and heptachlor were freshly applied at certain sites, which were all agricultural sites. The OCPs were spatially resolved as a function of the types of crops cultivated in different areas, legacy issues and recent applications. © 2013 Elsevier Ltd.
Characterization of Polycyclic Aromatic Hydrocarbons (PAHs) present in smoked fish from Ghana
(Advance Journal of Food Science and Technology, 2011-10) Palm, L.M.N.; Carboo, D.; Yeboah, O.P.; Quasie, W.J.; Gorleku, M.A.; Darko, A.
The study was conducted to determine the levels of Polycyclic Aromatic Hydrocarbons (PAH) in smoked Scomba japonicus sampled from some Ghanaian markets. By way of preparation, smoked fish comes into contact with smoke or extremely high temperature which are potential sources of PAH generation. Levels of 20 individual PAHs including acenaphthene, acenaphtyelene, anthanthrene, anthracene, benz(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(e)pyrene, benzo(ghi)perylene, benzo(j)fluoranthene, benzo(k)fluoranthene, chrysene, cyclopenta(cd)pyrene, dibenzo(ah)anthracene, fluoranthene, fluorene, indeno(1, 2, 3-cd)pyrene, naphthalene, phenanthrene and pyrene were determined in 34 smoked fish samples using gas chromatographic techniques with flame ionization detector. Benzo(a)pyrene, which is one of the very few PAHs for which a legal limit exists in different types of food matrices inaddition to other high molecular weight PAHs suspected to be carcinogens, were detected in most samples. © Maxwell Scientific Organization, 2011.
Chemical and Biological Characteristics of Some Marketed Solid Waste Composts in Ghana
(University of Ghana, 2002-12) Hogarh, J. N.; Carboo, D.; University of Ghana, College of Basic and Applied Sciences, Institute for Environment and Sanitation Studies
The study assessed the chemical and biological characteristics of composts made from municipal solid waste in Accra and agricultural waste in Kade in Ghana. In Accra, compost samples were taken at residential level (Household composting), decentralised community level (Asiedu- Keteke composting facility) and at large-scale metropolis level (Teshie composting plant). The compost samples from Kade were produced at the University of Ghana Agricultural Research Station. Composting operations at Teshie and Asiedu-Keteke were from mixed feed stock of organic material, newspapers, bottles, plastics, etc. and represented composting of un-segregated solid waste. The Household compost was produced from kitchen waste, whilst the Kade compost was produced from agricultural wastes (a mixture of cocoa pod husk, poultry droppings and saw dust). The Household and Kade composts were, thus, from purely organic sources. Public interest in composting in general was also assessed by way of questionnaires. The results indicated that the nutrient value, mainly nitrogen, phosphorus and potassium in the Accra composts, which were from municipal solid waste (MSW) were low compared to the compost from Kade, which was from agricultural waste. The differences in nutrient value reflected differences in feed-stocks for the composting. The composts from the mixed waste stream (Teshie and Asiedu-Keteke) did contain higher concentrations of heavy metals such as * lead and cadmium compared to the composts from pure organic sources (Household and Kade). However, the concentrations of the heavy metals found in the mixed waste composts, were not of levels that would pose significant health risk. The Asiedu-Keteke composts were found not to be matured and thus, may have restrictions for its use, particularly, for crop cultivation. All the other composts studied were found to be matured. The social survey indicated that respondents were less familiar with MSW derived composts in comparison to their knowledge on animal manure or yard waste composts. However, there was a potential for a positive public response to solid waste composting.
Defining options for integrated management of municipal solid waste in large cities of low-income economies - the case of the Accra metropolis in Ghana.
(2002) Fobil, J.N.; Carboo, D.; Clement, C.
Waste management and planning authorities need to know and understand the materials they will be handling or disposing in order to be able to set up effective sustainable waste management programmes. Also, in setting up a waste management programme for a region or city, it is critical to have reliable data on waste stream characteristics such as the nature, types and quantities of waste components in the waste streams of that locality. This will allow them to choose with fair certainty the kind of management options to consider for the implementation of an integrated solid waste management programme. The objective of this study was to analyse household solid waste to determine the type, nature and quantities of materials in the waste as generated so as to provide useful information on the potentially available management choices in the Accra metropolis. Results of the study show that, domestic solid waste in the metropolis can be routed via three distinctly different stream types; namely the High-Income Low-Density Population Waste Zone (HILDWZ), Middle-Income Medium-Density Waste Zone (MIMDWZ), and Low-Income High-Density population Waste Zone (LIHDWZ). These waste streams were also shown to consist of entirely different proportions of the waste components, but with an average percentage composition of 60% organic or putrescible materials, 8% paper & card, 8% plastic & rubber materials, 3% metal & cans, 2% glass, 11% residue or inert materials, and 2% miscellaneous or other waste.
Determination of selected elements in red, brown and green seaweed species for monitoring pollution in the coastal environment of Ghana
(Journal of Radioanalytical and Nuclear Chemistry, 2006-09) Serfor-Armah, Y.; Carboo, D.; Akuamoah, R.K.; Chatt, A.
The concentrations of 23 elements, namely Al, As, Br, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hf, Hg, I, K, La, Mg, Mn, Na, Ni, Sc, Sm, V, and Zn, in seven Rhodophyta (red), three Phaeophyta (brown) and five Chlorophyta (green) seaweed species from different areas along the coast of Ghana were determined using instrumental neutron activation analysis (INAA). These species can be potentially used as biomonitors. The INAA method involved irradiations using thermal and epithermal neutrons at the Dalhousie University SLOWPOKE-2 Reactor (DUSR) facility followed by conventional and anti-coincidence γ-ray spectrometry. The precision in terms of relative standard deviation was within ±4%. The accuracy of the methods was evaluated by analyzing four reference materials. Our results were within ±3% of the certified or information values in all cases. © 2006 Akadémiai Kiadó.
Distribution Of Heavy Metals In Cocoa Farm Soils In The Western Region Of Ghana
(University of Ghana, 2012-10) Ackah, J.E.; Carboo, D.; Nartey, E.K.; University of Ghana, College of Basic and Applied Sciences, School of Physical and Mathematical Sciences, Department of Chemistry
Western Region is the largest cocoa producer in Ghana. Cocoa farmlands have over the past decades received heavy doses of agrochemical application to boost cocoa production. These agrochemicals, however, may contain heavy metals and it is therefore likely that the metals may have accumulated in the soils. Evaluating the total concentrations and understanding the distribution characteristics of heavy metals in cocoa growing soils can aid environmental managers and even help regulate the rate of agrochemical application. A study was therefore, carried out on some selected soils of major cocoa growing areas in Western Region of Ghana to determine the levels of cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in the soils and also to determine some of the soil factors that control the distribution of the heavy metals in the soil. Eight soils (two Haplic Luvisols, three Ferric Acrisols, one Haplic Ferrasol and two Dystric Fluvisols) and their accompanying pristine soils as control were taken from adjacent natural forests sampled at depths of 0 – 10 cm, 10 – 30 cm, 30 – 50 cm, 50 – 80 cm and 80 – 100 cm. These soils were analysed for their particle size distribution, pH, organic carbon, cation exchange capacity, exchangeable bases, and total and bio-available Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. The study indicated that the ΔpH which is pHKCl – pHH2O were all negative indicating that the soils generally had net negative charges on their colloidal surface. For all soils, clay content and pH increased with depth indicating co-migration of the two soil parameters whilst total organic carbon content decreased with depth. Cation exchange capacity, however, did not show any clear pattern with depth in the soils. The average abundance of heavy metals determined in these soils decreased as follows: Fe > Mn > Cr > Zn > Cu > Cd > Pb > Ni. The soils had low metal contents, less than or within the range of concentration for non-polluted soils and for European norms. However, total concentrations of Cd, Cu, Cr and Pb in the surface soils (0 – 10 cm) exceeded the thresholds for atmospheric fallout concentrations in top soil to 20 cm depth indicative of anthropogenic contamination. The lowest heavy metal contents were observed in the Haplic Luvisols while the highest metal loadings were in the Haplic Ferrasols and the Dystric Fluvisols. Depth function plots, ANOVA and correlation analyses indicated that clay influenced the distribution of Cr, Cu, Fe, Ni and Zn in the soils. Clay and total organic carbon controlled Cd distribution while pH and clay were associated with the distribution of Mn. Thus, clay had the most pronounce effect on the distribution of the metals in the soils. Accumulation-depletion ratios, enrichment factors and principal component analysis indicated that the distribution of Cd, Cu, Mn and Pb in the soils highlighted an anthropogenic pollution, most probably, from agrochemical inputs and/or from atmospheric deposition. Iron and Ni distributions were associated with lithogenic origin whereas Zn and Cr distribution were related to both anthropogenic and lithogenic contributions.
Epithermal instrumental neutron activation analysis for the determination of gold and arsenic in Ghanaian gold tailings using conventional and anti-coincidence counting
(Journal of Radioanalytical and Nuclear Chemistry, 2003-01) Nyarko, B.J.B.; Serfor-Armah, Y.; Holzbecher, J.; Osae, E.K.; Akaho, E.H.K.; Carboo, D.; Chatt, A.
Epithermal instrumental neutron activation analysis (EINAA) together with both conventional and anti-coincidence counting techniques were used to analyze six different gold tailing samples from Ghana for Au and As. The method involves the use of the epi-cadmium site of the Dalhousie University Slowpoke-2 reactor facility for the irradiation of the samples. After irradiation, the samples were counted directly on the detectors. The identification and quantification of the elements were done using 411 keV photopeak of 198Au and both 559 keV and 657 keV photopeaks of 76As. The precision and accuracy of the method were evaluated-Values for Au in the samples ranged from 2.48 ppm and 6.76 ppm and for As between 1,550 ppm and 3,460 ppm. The values obtained using the two counting systems were in good agreement while the anti-coincidence counting system gave values of higher precision and accuracy. The detection limit for Au were 20 and 10 ppb for the conventional and anti-coincidence spectrometric systems, respectively, and 50 ppb for As in both cases. Details of the method and results are presented.
Evaluation of municipal solid wastes (MSW) for utilisation in energy production in developing countries.
(2005) Fobil, J.N.; Carboo, D.; Armah, N.A.
In countries such as Ghana, which are still undergoing restructuring in their economies, low-cost energy s upplies are most vital for development initiatives and may not only be the main constraint to their economic growth, but a principal source of conflicts in th is century. But whether a meaningful and sustainable economic growth would be ach ieved or not rests exclusively on the removal of these energy constraints either by way of substitution for increasingly expensive conventional ener gy sources or new discoveries of cheaper alternatives that would power th eir industries. Such alternative sources should not only be cheap with great capability of promoting viable economies of scale, but also should be eco-efficient. Today, the traditional energy sources su ch as hydroelectric power, wood fuel, and oils are increasingly less attractive with a grown knowledge of their effects on the natural environment. This paper di scusses research experiences gathered during a study that was undertaken in Accra, Ghana, to explore the potential for utilising municipal solid waste (MSW) for energy generation in a low-income economy and at the same time, address worsening MSW problems in the major cities. The results show that MSW in a typical low-income country is wet with low calorific values between 14 MJ/kg and 20 MJ/kg and an average energy recovery efficiency of about 40%.
Exposure and Fate of Neonicotinoid Insecticides in Cocoa plantations in Ghana
(University of Ghana, 2015-07) Dankyi, E.; Carboo, D.; Gordon, C.; Fomsgaard, I. S; University Of Ghana, College of Basic and Applied Sciences ,School of Physical and Mathematical Sciences, Department of Chemistry
Neonicotinoids belong to the most important class of insecticides currently used in crop production and account for about a fourth of the insecticide market. They are considered highly effective against insect pests, safe to mammals, and possess multiple means of application for convenience and widespread usage in diverse crop protection. Neonicotinoids are systemic insecticides - they are absorbed into plants, travel through the vascular tissue, and help protect the plant from piercing and sucking insects. Their mode of action is through agonist activity at the postsynaptic nicotinic acetylcholine receptor (nAChRs) sites in the nervous system. In recent years, reports have emerged on possible harmful effects of neonicotinoid insecticides on bee health. Across Europe, America and Australia, there has been calls for ban and reevaluation of the use of neonicotinoid insecticides. In Europe, a ban has been in place for almost two years following a scientific report by the European Food Safety Authority (EFSA) which identified “high acute risks” for bees. However, the availability of conflicting reports on the effects of neonicotinoids on bees has prompted intense research on these class of insecticides. Quite clearly, understanding the effects of neonicotinoids on organisms in the ecosystem will rely on accurate knowledge of their exposure in the environment. In Ghana, neonicotinoids are one of the most widely used class of insecticides particularly in cocoa production, where they are important for the control of mirids. Insect pests are a major concern in crop production in tropical conditions, due to the prevailing conducive environment for their growth. In cocoa production, insect pests such as mirids contribute to significant loses in yield. To address this concern, the government of Ghana introduced a free mass application policy on insecticides in cocoa farming, which has contributed to substantial improvements in yields of cocoa beans. Under the program, neonicotinoids are the major class of insecticides used. In spite of the remarkable contribution of neonicotinoids to cocoa production, concerns about the environment and food safety have arisen due to widespread and intensive use of these chemicals in cocoa farms. Addressing these concerns requires accurate knowledge of the behavior and fate of these class of insecticides in the Ghanaian environment. The primary goal of this work was to assess the extent of exposure, behavior and fate of neonicotinoids in the Ghanaian environment, particularly in cocoa plantations where they are extensively used. To achieve this, concentrations of neonicotinoid residues in soils across all the cocoa producing regions of the country were studied to examine their environmental exposure. Their fate in soils was studied by investigating their dissipation and sorption behavior using established kinetic models and isotherms. Finally, the exposure to cocoa beans (food) was studied to ascertain concerns for food safety. Analytical methods and instrumentation was an important aspect of this work to ensure accurate and reliable data. To this end, the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) procedure was optimised and used for the diverse matrixes understudy. Quantification of analytes involved the use of liquid chromatography- tandem mass spectrometry (LC-MS/MS) for high sensitivity and low detection limits in the complex soil and cocoa matrixes used. The findings from the study suggest that, neonicotinoids are persistent in the Ghanaian soils studied and may be found in soils several months to years after application. Sorption studies revealed that, sorption coefficients of neonicotinoids are generally low, with a high potential for leaching into surface and underground water systems. Due perhaps to their systemic nature and high application rates, neonicotinoids may accumulate to high levels in cocoa beans, particularly in cocoa shells. The findings from this study has implications for pesticide application and current policy on pesticide usage, and reveal that, efficient application regimes are needed in cocoa production to ensure food and environmental safety.
Groundwater Contamination with Toxic Metals through Small Scale Mining within the Lower Pra Basin
(University of Ghana, 2013-06) Dorleku, M.; Carboo, D.; Nukpezah, D.
Small-scale gold mining in Ghana is mainly an informal industry employing thousands of people. The generally undeveloped nature of the industry has resulted in lack of proper monitoring and supervision by relevant authorities. As a result, there is wanton destruction of farm lands and indiscriminate pollution of water bodies. These water bodies serve us recharge zones for groundwater, thereby polluting them. This study assessed the effects of small-scale gold mining on quality of groundwater in the Lower Pra Basin in terms of heavy metal and other physico-chemical pollution. The analysis shows that pH values are generally low in the Basin. More than 95 % of dry season and almost all the wet season values are acidic or slightly acidic. Approximately 35 % of boreholes in the wet season recorded values for Cadmium above W.H.O guideline value of 3.0 μg/l. Only two boreholes recorded values above W.H.O guideline value for the dry season. The higher wet season pollution suggests anthropogenic origin for Cd. Generally, high values were recorded for Iron, Manganese, Lead, Aluminium and Hg. Approximately 15% and 18 % of dry and wet season values respectively for Fe were above W.H.O recommended limit of 300 μg/l for drinking water with a mean of 218 μg/l and a median of 166 μg/l. Manganese concentration was in the range 2.5 - 1544 μg/l with a mean of 142 μg/l. Roughly 5 % and 11 % of the dry and wet season values respectively, were above the W.H.O recommended value of 500 μg/l. The concentration of Lead was higher than 10 μg/l (W.H.O guideline value) in 43% and 41% of the dry and wet season values respectively with a mean of 15.8 μg/l and 20.1 μg/l for dry and wet seasons respectively. About, 88% and 42% of the dry and wet season values, respectively, were above the W.H.O limit of 1.0μg/l for mercury. Dry season values ranged between 0.005 and 10.1μg/l with the wet season recording values between 0.005 to 16.4 μg/l. Approximately 17 % and 11 % of dry and wet seasons respectively recorded values above the W.H.O recommended limit of 200 μg/l for Aluminium. Other heavy metals present but were generally below W.H.O guideline values or were in insignificant concentrations include Copper, Arsenic, selenium and Zinc. Values recorded for Phosphate, Sulphate and Nitrate are within acceptable limits. In general, Lead, Copper, Cadmium, and Manganese showed higher wet season values than dry season suggesting anthropogenic influence .
Harmonizing procedures for the evaluation of compost maturity in two compost types in Ghana
(Resources, Conservation and Recycling, 2010-01) Ofosu-Budu, G.K.; Hogarh, J.N.; Fobil, J.N.; Quaye, A.; Danso, S.K.A.; Carboo, D.
Composting is one of the most favoured options for municipal solid waste recycling for waste streams with high content of biodegradable materials. Compost has many uses including its use in agriculture for soil structure and fertility improvement. However, non-mature composts when applied to soils could present inimical phytotoxic problems to crops. Despite this reality, many developing countries including Ghana, lack simple and reliable compost maturity tests, and run the risk of producing and/or using composts that have not reached maturation stage. This study was conducted to validate some chemical and biological procedures for testing the maturity of composts prepared from agricultural residues (AR) and municipal solid wastes (MSW) in Ghana. Three maturity indices - humus colour, CO2 respirometry, and germination index - were considered for this validation study. For composts produced from crop residues, the optimal values for humus colour test, CO2 evolution test, and germination index were 0.36-0.59, 1.24-1.80 gCO2 kg-1 day-1, 159.5-259.4, respectively. Similarly for the MSW composts the optimal maturity index ranges were 0.41-0.51 for humus colour test, 0.43-0.56 g CO2 kg-1 day-1 for CO2 evolution test and 0-59.1 for germination index. The MSW composts appeared mature under humus colour and CO2 evolution tests, but inhibited germination. Agricultural residue composts on the other hand were found to be mature when subjected to all three maturity tests. This is indicative that composts may pass certain maturity parameters, yet fail germination test. It is therefore concluded that the germination test index is able to discriminate better between mature and non-mature composts. © 2009 Elsevier B.V. All rights reserved.
The influence of institutions and organizations on urban waste collection systems: An analysis of waste collection system in Accra, Ghana (1985-2000).
(2008-01) Fobil, J.N.; Armah, N.A.; Hogarh, J.N.; Carboo, D.
Urban waste collection system is a pivotal component of all waste management schemes around the world. Therefore, the efficient performance and the success of these schemes in urban pollution control rest on the ability of the collection systems to fully adapt to the prevailing cultural and social contexts within which they operate. Conceptually, institutions being the rules guiding the conduct of public service provision and routine social interactions, waste collection systems embedded in institutions can only realize their potentials if they fully evolve continuously to reflect evolving social and technical matrices underlying the cultures, organizations, institutions and social conditions they are designed to address. This paper is a product of an analysis of waste collection performance in Ghana under two different institutional and/or organizational regimes; from an initial entirely public sector dependence to a current mix of public-private sector participation drawing on actual planning data from 1985 to 2000. The analysis found that the overall performance of waste collection services in Ghana increased under the coupled system, with efficiency (in terms of total waste clearance and coverage of service provision) increasing rapidly with increased private-sector controls and levels of involvement, e.g. for solid waste, collection rate and disposal improved from 51% in 1998 to about 91% in the year 2000. However, such an increase in performance could not be sustained beyond 10 years of public-private partnerships. This analysis argues that the sustainability of improved waste collection efficiency is a function of the franchise and lease arrangements between private sector group on the one hand and public sector group (local authorities) on the other hand. The analysis therefore concludes that if such franchise and lease arrangements are not conceived out of an initial transparent process, such a provision could undermine the overall sustainability of private sector initiatives in collection services delivery in the long term, as in the case of the Accra example.
Instrumental neutron activation analysis of iodine levels in fourteen seaweed species from the coastal belt of Ghana.
(2000-08-01) Serfor-Armah, Y.; Nyarko, B.J.B.; Carboo, D.; Osae, E.K.; Anim-Sarpong, S.; Akaho, E.H.K.
Fourteen seaweed species were sampled from October 1997 to May 1999 along the rocky shores of Ghana, which is being washed by the Gulf of Guinea (part of the Atlantic Ocean). Instrumental neutron activation analysis (INAA) was used to measure the iodine levels in the species, with the basic aim of selecting seaweed species that are rich in iodine and hence can be used as supplement in the diet of humans. This is to help solve the problems associated with iodine deficiency disorders (IDD). The levels of iodine found in the seaweed species ranged between 55 to 804 ppm. The precision, expressed in terms of relative standard deviation, and accuracy of measurements are within ±5–10%. The results show high variability in and between species and among sampling sites. The high values of iodine concentrations in the macroalgae suggest that these marine organisms can be used as supplement in the diet of humans.
Isolation and identification of some plant growth promoting substances in compost and co-compost.
(International Journal of Virology 4(2): 30-40., 2008) Hogard, J.N.; Fobil, J.N.; Carboo, D.; Ofosu-Budu, G.K.; Ankrah, N.A.; Nyarko, A.
In this study, plant growth hormones in compost or co-compost prepared from human excreta and/or municipal solid waste were extracted and identified. Water (deionized) or 80% methanol (chilled) extracts were prepared from the composts for the isolation and identification of plant growth substances. The methanolic extracts of plant growth hormones fraction was further partitioned into cytokinin (fraction) using ethyl acetate and n-butanol; auxins (fraction) using diethyl ether and gibberellins (fraction) using sodium hydrogen carbonate and n-butanol. Five different concentrations of standard plant growth hormones; Benzyl Amino Purine (BAP), Gibberellic Acid (GA3) and Indole-3-Acetic Acid (IAA) were prepared and used in a bioassay test to compare the effects and concentration of the extracted plant growth hormones from the compost and co-compost. The presence of some plant growth hormones in the extracted samples from compost or co-compost was confirmed using the relative fluidity, (Rf) values of the co-chromatography using a standard hormone and the extracted plant growth hormones. The results indicated the presence of plant growth substances such as IAA, GA3 and cytokinins. In co-compost, the concentration of hormone were found to be 68.3 to 345.1 mg kg-1, 61.9 to 185.8 mg kg-1 and 250.4 to 312.7 mg kg-1 for auxins, cytokinins and gibberellins, respectively. Whereas in compost 42.0 to 248.8 mg kg-1, 33.1 to 198.3 mg kg-1 and 10.1 to 200.2 mg kg-1 of auxins, cytokinins and gibberellins, respectively were found.
Levels and seasonal variations of organochlorine pesticides in urban and rural background air of southern Ghana
(Environmental Science and Pollution Research, 2012-06) Adu-Kumi, S.; Kareš, R.; Literák, J.; Borůvková, J.; Yeboah, P.O.; Carboo, D.; Akoto, O.; Darko, G.; Osae, S.; Klánová, J.
Urban, suburban and rural background air samples were collected in southern Ghana in 2008 employing polyurethane foam disc passive air samplers (PAS). PAS were analysed for organochlorine pesticides (OCPs), namely hexachlorocyclohexanes (α-, β-, γ- and δ-hexachlorocyclohexane), dichlorodiphenyltrichloroethane including metabolites (o,p′- and p,p′-DDT, DDE and DDD), hexachlorobenzene, pentachlorobenzene, aldrin, dieldrin, endrins (endrin, endrin aldehyde and endrin ketone), isodrin, heptachlors (heptachlor, heptachlor epoxide A and heptachlor epoxide B), chlordanes (α-, β-chlordane, oxychlordane and trans-nonachlor), endosulfans (α- and β-endosulfan and endosulfan sulphate), methoxychlor and mirex using a gas chromatograph coupled to a mass spectrometer. The levels of OCPs ranged for the individual pesticides from below limit of quantification to 750 pg m-3 (for α-endosulfan), and current agricultural application seemed to be the main primary source of most abundant pesticides. Re-volatilization of previously used pesticides from contaminated soils could not be ruled out either as potential secondary source of contamination, especially in warm and dry seasons and periods of intensive agricultural activities. Higher atmospheric concentrations were observed in November and December during the dry season compared to lower concentrations observed in June, July and August when the country experiences heavy rains. The highest seasonal variation was observed for currently used pesticides as α-endosulfan. A p,p′-DDT/p,p′-DDE ratio suggested recent inputs of fresh technical DDT. © 2012 Springer-Verlag.
Micelle-mediated extraction and neutron activation determination of nanogram levels of vanadium in seaweeds
(Journal of Radioanalytical and Nuclear Chemistry, 2018-12) Serfor-Armah, Y.; Carboo, D.; Akuamoah, R.K.; Chatt, A.
A simple one-step micelle-mediated extraction, commonly called cloud point extraction, method was developed for the preconcentration of vanadium in red, brown and green seaweeds. The recovery of vanadium under the optimized conditions of pH 3.7, [PAN/TAN] = 1×10−4 M, [PONPE-20] = 0.1% (m/v), ionic strength = 0.05 M KNO3, and a temperature of 41 °C was > 99%. Vanadium was assayed by neutron activation analysis using the Dalhousie University SLOWPOKE-2 reactor facility. The detection limits for vanadium varied from 0.6 to 3.9 µg kg−1 depending on the sample. The method was validated using certified reference materials. Mass fractions of vanadium in seaweeds ranged from 0.009 to 55.4 mg kg−1. © 2018, Akadémiai Kiadó, Budapest, Hungary.