Browsing Environmental Science by Issue Date
Previous Page
Now showing items 41-51 of 51
-
Mbaiwa, J.E.; Sakuze, L. K. (Taylor and Francis http://dx.doi.org/10.1080/14766820902829551, NaN, 2009)[more][less]
Abstract: This paper uses the livelihoods framework to analyse how cultural tourism can diversify livelihoods at XaiXai village in the Okavango Delta, Botswana. Both primary and secondary data sources were used in this study. Primary data sources included household and key informant’s interviews conducted at XaiXai village and Gcwihaba Caves. Secondary data included both published and unpublished materials on cultural tourism, XaiXai village and Gcwihaba Caves. Results indicate that the San(Basarwa) of XaiXai’s traditional life of hunting and gathering has become a cultural tourism product in the Okavango Delta. Gcwihaba Caves’ geological formation particularly the stalagmites, stalactites and channels also attract tourists that visit the Okavango Delta. The caves also have a cultural history in that they were used as a hiding place by the Basarwa in times of wars, rainy season and cold winters. As such, the cultural values of the San of XaiXai and Gcwihaba Caves are cultural tourism products that can diversify livelihoods at XaiXai village. Therefore, policies and strategies that address cultural tourism and rural livelihoods in tourism destination areas need to be developed. The Gcwihaba Caves and Xaixai Village case study demonstrates that cultural tourism can be a tool for rural livelihoods diversification in tourism destination areas of developing countries. URI: http://hdl.handle.net/10311/482 Files in this item: 1
Mbaiwa_JTCC_2009.pdf (899.2Kb) -
Meck, M.; Atlhopheng, J.; Masamba, W.R.L. (Elsevier http://www.linkinghub.elsevier.com/retrieve/pii/S1464343X09000491, NaN, 2009)[more][less]
Abstract: Alkaline rocks (phosphate deposits in particular) of igneous origin are currently being mined in Zimbabwe. Exploitation of these deposits, which are associated with metals and non-metals, provides a potential for changing the river water quality in the surrounding areas by increasing metal and phosphates levels in the water, thereby endangering the beneficial use of the river. The aim and objectives of this paper are to enumerate the current impacts associated with mining alkaline rocks on Save River water quality in Zimbabwe using the Dorowa mine as a case study. Though there are several impacts associated with the mining of alkaline rocks, this paper deals only with impacts on water quality. A preliminary assessment of the water quality in the Save River downstream of the Dorowa phosphate mine showed an increase in conductivity, iron content, manganese content, nitrates and hardness when compared to those taken before mining activity began. However, there was no notable increase in phosphate and metals except for Fe and Mn. A plausible explanation for the low phosphate values in the water is that the phosphates are precipitating and settling as sediments. Phosphate is known to effectively remove metals from the surface water through the formation of metal–phosphate minerals. Thus, various pollutants may be adsorbed into sediments accumulated on the bottom of the river. These sediments may accumulate pollutants over long periods and act as new pollutant sources to the overlying water when phosphate desorbs from sediments due to changes in water conditions. Therefore, the sediments can act as a source of water pollution in the future URI: http://hdl.handle.net/10311/409 Files in this item: 1
Meck_JAES_2009.pdf (495.8Kb) -
Ntshwene, K.; Kashiwagi, J.; Kashiwagi, D. (Royal Institute of Chartered Surveyors http://www.rics.org/site/download_feed.aspx?fileID=5042&fileExtension=PDF, NaN, 2009)[more][less]
Abstract: The traditional contracting/delivery system in Botswana, introduced by the US, UK, and European educators, consultants, and practitioners, has not been working well in Botswana. The poor project delivery system results have forced the organization of a new group, the Government Implementation Coordination Group (GICO) to attempt to solve the problems. In the fall of 2008, the University of Botswana (UB), through the US State Department sponsored Fulbright program, brought professor Kashiwagi, and the best value Performance Information Procurement System (PIPS) technology, the Information Measurement Theory (IMT), and the Industry Structure Analysis to the UB project management section. This paper proposes that the client’s professional representative requires a new, more effective role. The role includes using performance information, transforming the client’s expectations into a design/construction intent by using expert vendors, ensuring the vendors manage and minimize the risk that they do not control, outsourcing the technical responsibilities, and doing quality assurance instead of quality control. This paradigm will minimize project risk, maximize project value, and increase the professionalism of project management, construction management, and quantity surveyors. These concepts will be tested on three test projects in Botswana. URI: http://hdl.handle.net/10311/473 Files in this item: 1
Ntshwene_COBRA_2009.pdf (1.344Mb) -
Meck, M.L.; Atlhopheng, J.; Masamba, W.R.L.; Ringrose, S. (Elsevier Science Ltd, http://www.elsevier.com/locate/pce, NaN, 2010)[more][less]
Abstract: The study set out to determine the weathering and dissolution of metal hosting minerals at Dorowa for purposes of deducing pollution potential to the nearby Save River. Phosphate rock is mined at Dorowa for the production of phosphate fertilizer. The major minerals found in the ring complex are feldspars, pyroxenes, apatite, magnetite and calcite. Chemical analysis established that the rocks are associated with metals that include copper, lead, zinc, cobalt, nickel, tin and cadmium. Among the many minerals present apatite and calcite host metals more than the other minerals due to their crystal structure. This study investigated the weathering and dissolution of these two minerals. Both apatite and calcite dissolve in natural environmental conditions prevalent at Dorowa. From the analysis the study concludes that the potential availability of metals trapped in the calcite and apatite structures is high. The understanding of weathering and dissolution of metal hosting minerals is important in predicting quality of water around the study area, because most villagers use the Save River as their primary drinking water source. URI: http://hdl.handle.net/10311/1021 Files in this item: 1
Atlhopheng_PCE_2010.pdf (758.1Kb) -
Dikinya, O.; Areola, O. (Springer, http://link.springer.com/, March NaN, 2010)[more][less]
Abstract: The use of treated urban wastewater for irrigation is a relatively recent innovation in Botswana and knowledge is still limited on its impact on soil heavy metal levels. The aim of this study is to analyze and compare heavy metal concentration in secondary wastewater irrigated soils being cultivated to different crops: olive, maize, spinach and tomato in the Glen Valley near Gaborone City, Botswana. The studied crop plots have been cultivated continuously under treated wastewater irrigation for at least 3 years. Most crop farms have sandy loam, loamy sand soils. Based on food and agriculture organization, heavy metal threshold values for crop production have been studied. Results showed that the wastewater irrigated soils in the Glen Valley have higher cadmium, nickel and copper than desirable levels, while the levels of mercury, lead and zinc are lower than the maximum threshold values recommended for crop production. The control sites show that the soils are naturally high in some of these heavy metals (e.g copper, zinc, nickel) and that crop cultivation under wastewater irrigation has actually lowered the heavy metal content. Comparing between the crops, mercury and cadmium levels are highest in soils under maize and decline linearly from maize to spinach to olive to tomato and control site. By contrast, concentrations of the other metals are at their lowest in maize and then increase from maize to spinach to olive to tomato and to control site. URI: http://hdl.handle.net/10311/1105 Files in this item: 1
ijest 2010 dikinya and areola.pdf (685.3Kb) -
Dikinya, O.; Mufwanzala, N. (Academic Journals, http://www.academicjournals.org/JSSEM, May NaN, 2010)[more][less]
Abstract: The utilization of chicken manure as an organic fertilizer is essential in improving soil productivity and crop production. We carried out the study to assess the effects of chicken manure on soil chemical properties and the response of application rate on the yield of spinach (Spinacia oleracea) as well as the uptake of nitrogen and phosphorus nutrients. To quantify these effects, we added chicken manure to samples of Calcisols, Arenosols and Luvisols at application rates: 5, 10, 20 and 40% chicken manure. The addition of chicken manure irrespective of application rate did not change the acidity or pH of Calcisol, suggesting its hypo-buffering capacity. While the results reveal increases of EC with increasing rate, at rate above 40%, the ECs were above the critical salinity level of 4 mS/cm indicating potential threat to soil productivity. The exchangeable bases increased with application rate, suggesting the positive effects of chicken manure in enhancing soil fertility. Similarly significant increase of nitrogen and phosphorus were observed following the addition of chicken manure. Initially the spinach yield increases up to optimum rate of 0.06, 0.07 and 0.16 g/plant for Luvisol, Arenosol and Calcisol, respectively and subsequently drops after critical threshold values; 15, 5 and 1% for Calcisol, Arenosol and Luvisol, respectively. Interestingly above the rate of 40%, the yield was almost zero for all soils, suggesting the ineffectiveness of chicken manure in enhancing soil productivity. URI: http://hdl.handle.net/10311/1003 Files in this item: 1
Dikinya_JSSEM_2010.pdf (514.6Kb) -
Kizza, S; Areola, O (Academic Journals, November NaN, 2010)[more][less]
Abstract: This study investigated the influence of the accumulation of animal wastes on the soils of active kraal sites through time. This investigation involved the sampling and analysis of the soils of kraals that had been in use for periods ranging from 2 to over 45 years. Soil sampling and analysis were done both in the dry and wet seasons for comparative purposes. The properties of the kraal soils were compared with those of control sites. Samples were taken from 25 kraals categorized into 5 age (length of use) groups: < 5years; 6 - 10; 11 - 20; 21 - 40; > 40 years. The soils were sampled at two depths, 0 – 15 and 15 – 35 cm. Soil parameters analyzed included particle size distribution (%), bulk density (g/cm3), pore space (%), moisture content (%), pH in water and in potassium chloride solution, EC (μS/cm), organic matter (%), CEC (meq/100g), exchangeable bases: Ca++(cmolc/kg), Mg++(cmolc/kg), K+(cmolc/kg), Na+(cmolc/kg); nitrogen: NH4-N (mg/kg), NO3-N (mg/kg), TKN (%), and Olsen P (mg/kg). Results showed a direct correlation between length of active kraal utilization and impact of animal waste concentration on the soil with correlation coefficients as high as r = 0.99 and r = 0.95 for pH and OM respectively. Nutrient levels in kraal soils of all ages were significantly higher (P = 0.05) than those of the control site soils. Most nutrient elements showed increases ranging from about 2 - 30 times greater than in the control site soils. Soil nutrient levels were higher in the dry season than in the wet season. The nutrient enrichment in the kraals extended deep into the soil, at least, to the 35 cm depth. The organic and nutrient enrichments of the soils also had very positive effects on soil moisture and structural characteristics. However, this highly localized nutrient enrichment of kraal soils is detrimental to the long term sustainability of arid ecosystems and soil productivity. The nutrients concentrated in kraals have been harvested from the surrounding areas by grazing animals and transferred to the kraal sites. In a situation of sedentary kraaling that exists in semi arid lands of Botswana where rotation of kraal sites or the harvesting of animal manure from kraals for use as soil manure is not commonly practiced, the concentration of soil nutrients at scattered kraal spots causes an imbalance in the spatial pattern of soil and plant productivity in the arid land ecosystem. The entire ecosystem is made poorer by this phenomenon. Description: Full Length Research Paper URI: http://hdl.handle.net/10311/1095 Files in this item: 1
Kizza and 0Areola.pdf (293.8Kb) -
Meck, M.L.; Atlhopheng, J.; Masamba, W.R.L.; Ringrose, S.; Diskin, S. (Bentham Open, http://www.benthamscience.com/open/tomj/index.htm, NaN, 2011)[more][less]
Abstract: This study set out to establish the major minerals at Dorowa and determine which of those are likely to host metals that may leach into surface and groundwater. This study comes after a preliminary assessment of the water quality in the Save River downstream of the Dorowa phosphate mine in Zimbabwe showed an increase in conductivity, iron content, manganese content, nitrates and hardness when compared to those taken before the mining area. X-Ray Diffractometry (XRD) was used to establish the major minerals at Dorowa whilst Inductively Coupled Plasma Mass Spectrometry (ICP- MS) was used to establish the chemistry of the rocks. The results from this study show that the major minerals in the rocks around Dorowa are feldspars, pyroxenes, apatite, magnetite and calcite. The metals hosted by the rocks include Ag, As, Be, Cd, Co, Cu, Pb, Hg, Ni, Sb, Se and Zn. The study concludes that the minerals likely to host metals are calcite and apatite. Metal hosting is higher in apatite minerals than in calcite. Metal hosting by the other minerals observed in the study area is low. URI: http://hdl.handle.net/10311/1109 Files in this item: 1
Atlhopheng_OMJ_2011.pdf (848.6Kb) -
Areola, O.; Dikinya, O.; Mosime, L. (Global Science Books, http://www.globalsciencebooks.info/Journals/AJPSB.html, NaN, 2011)[more][less]
Abstract: This study compares soil quality parameters, and salinity and heavy metal levels in soils cultivated with different crops under secondary treated wastewater irrigation in the Glen Valley, near Gaborone City, Botswana. The hypothesis being tested is that the impact of wastewater on soil quality varies with soils and crop types. The study covers 4 selected crops, maize (Zea mays L.), spinach (Spinacia oleracea), olive (Olea europaea), and tomato (Solanum lycopersicum), most widely cultivated by the farmers. Three farm plots per crop type were sampled at 5 sampling points and at two soil depths, 0-15 and 15-30 cm. Samples were also collected at 5 sampling points from two control sites. Irrigation water samples were collected from microbiological analysis from 2 farms per crop type. The most significant differences and relationships are between those crop farms, such as maize and two of the spinach plots, with predominantly sandy soils (loamy sands – sand loams) on the one hand, and the olive, tomato and one of the spinach plots with sandy clay loams on the other. The importance of soil texture was confirmed by the strong correlations between the sand and silt contents, several soil quality parameters, heavy metals and other elements. With the exception of Cd and Hg, most soil heavy metal contents were lower on the irrigated plots than on the control plot. The EC values also show that soil salinity levels were still low on the irrigated fields, but SAR and ESP values were high. The secondary treated wastewater being used in the Glen Valley is biologically clean, but one recorded case of E. coli emphasizes the importance of avoiding sprinkler irrigation at all costs to protect human health. URI: http://hdl.handle.net/10311/1002 Files in this item: 1
Dikinya_AJPSB_2011.pdf (249.7Kb) -
Meck, M.L.; Masamba, W.R.L.; Atlhopheng, J.; Ringrose, S. (Elsevier Science Ltd, http://www.elsevier.com/locate/pce, NaN, 2011)[more][less]
Abstract: The objective of the study was to investigate the role played by the natural environment in protecting the transboundary Save River from the impacts of metals derived from phosphate mining at Dorowa. The study is a follow up study from a previous one that noted that there is natural attenuation at Dorowa. Water and sediment samples were collected in the Save River and the streams that drain the Dorowa dumps. Inductively coupled plasma mass spectrometry (ICP–MS) was used to analyze the cations (Na+, K+, Ca2+, Mg2+, Cu2+, Co2+, Fe2+, Ni2+, Zn2+, Pb2+, Sn2+, Mn2+, Cd2+) in the samples. Major anions Cl , SO2 4 and NO 3 were analyzed by standard chromatography whilst CO2 3 and HCO 3 were determined by titration. pH was measured on site. Geochemical modeling of the water composition was conducted with Visual Minteq. The results show that natural attenuation is being achieved through precipitation of solids from the water and subsequent deposition onto the sediments. Six of the metals are almost completely precipitated (Cu 99.99%, Fe 99.39%, Ni 91.24%, Pb 99.87%, Sn 99.99% and Zn 88.66%). However Mn, Co and Cd remain in solution. Thus the natural environment is protecting the Save River which is a transboundary river from the impacts of mining through precipitation of the metals. Users downstream of Dorowa mine are therefore not being affected by mining pollution. This study demonstrates that besides being a legitimate and important user of water, the natural environment can also play a significant role in protecting water quality by attenuating metals naturally. By analyzing costs incurred in several places where alternative methods are employed to remediate metal related pollution the study concludes that natural remediation at Dorowa is saving the nation in environmental costs. Therefore the paper advocates for appreciation of the role that the natural environment plays in protecting ecosystems from the impact of human developments and environmental costs. Subsequently, this calls for recognition of natural environment’s role in water resources management for the sustenance of ecosystems and peoples livelihoods. URI: http://hdl.handle.net/10311/963 Files in this item: 1
Atlhopheng_PCE_2011.pdf (630.3Kb) -
Kizza, Sarah; Totolo, Otlogetswe; Perkins, Jeremy; Areola, Olusegun (Academic Journals, http://www.academicjournals.org, December 4, 2011)[more][less]
Abstract: The aim of this study was to analyze the depletion of soil nutrients with time on abandoned kraals in a peri-urban area of Botswana. Active kraals are enriched with nutrients through the accumulation of animal droppings and this study was aimed at assessing how long the impact of this soil nutrient enrichment persists after kraal abandonment. A total of 25 disused kraals, that had been abandoned for periods ranging from 1 to 45 years were sampled. The soil parameters analyzed included particle size distribution (%), bulk density (g/cm3), pore space (%), moisture content (%), pH in water and KCl solution, EC (μS/cm), organic matter (%), CEC (meq/100g), exchangeable Ca++(cmolc/kg), Mg++(cmolc/kg), K+(cmolc/kg), Na+ (cmolc/kg), nitrogen [NH4-N (mg/kg), NO3-N (mg/kg), TKN (%), and Olsen P (mg/kg). Results showed that soil nutrient concentrations on abandoned kraals generally were significantly higher than at the control sites. Soil nutrient concentrations decreased with time as abandoned kraals retrogressed towards their pre-kraal conditions. However, the effects of soil nutrient enrichment from animal wastes persist long after kraal abandonment. For example, soil Olsen P, Ca++ and Mg++ levels in kraal sites that had been abandoned for over 45 years were still significantly higher than in the control sites. In a pastoral system such as is practiced in Botswana where kraal manure is not used as soil amendment, the whole ecosystem suffers as soil nutrients are transferred and concentrated at isolated spots (kraals). Description: Full Length Research Paper URI: http://hdl.handle.net/10311/1016 Files in this item: 1
Kizza et al.pdf (696.1Kb)
Previous Page
Now showing items 41-51 of 51