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The Buriganga River has dramatically been disrupted due to extreme reduction of its water flow and encroachment of the banks and rigorous pollution due to human waste, industrial garbage and solid waste dumping. Thus Buriganga poses serious environmental threats to the Dhaka city.s sustainable environment. Using GIS tools it is revealed that the first risk to be considered is the amount of decreasing water which is putting a threat on the life of the Buriganga River as well as the whole ecosystem of the surrounding region. The second hazard is considered as decreasing vegetation due to the growing up of built up area and river land conversion to agricultural field. The Buriganga River is now highly polluted and becoming more or less dead due to dumping clinical, industrial and household wastes, industrial effluents, and discharge of oil from river vehicles. Due to the severe pollution and loss of normal flow of water, the Buriganga River effects on the environment, social and economical impacts of the surrounding area. These are the great threat and health hazard risk for the inhabitants of the nearby area. Unfortunately there is no distinct river basin committee yet, even not for all other rivers. In the National Water Policy 1999, the first term river basin management came which only defines some common issues of river problems mainly focusing on the flood. No IWRM implementation policy is practiced in the country. This research work recommends promoting a sustainable environment in the Dhaka city area and healthier life for its inhabitants. It is essential to save the surrounding river system especially the Buriganga River. An integrated river basin organization is highly necessary to implement IWRM approach to save the river. The present study reveals that governmental weak institutional setup and lack of enforcement of existing laws and policy are the main obstruct to save the Buriganga River.

付記する学位プログラム名: グローバル生存学大学院連携プログラム / 京都大学 / 新制・課程博士 / 博士(工学) / 甲第23163号 / 工博第4807号 / 新制||工||1752(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 立川 康人, 教授 田中 茂信, 准教授 佐山 敬洋 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Aviation greenhouse gas (GHG) emissions have risen faster than any other transport sector to double between 1990 and 2005. Such emissions from aviation could increase another 700 percent globally, and at least 150 percent in the European Union (EU), by 2050 due to continuously increasing consumer demand. To reverse the trend of rising emissions writ large, the EU has set 2030 climate goals of reducing its GHG emissions by 40 percent (relative to 2005) and having 32 percent of gross final energy consumption from renewables. The EU’s recast Renewable Energy Directive (RED-II) calls for 14 percent of transport energy from renewables, gives multipliers to advanced biofuels, and restricts biomass that is from ecologically valuable lands or that causes land use change. Energy security and energy independence are also long-term EU goals. Many of these goals and targets have also been adopted by the European Free Trade Area (EFTA). Despite these efforts, options are limited to reduce aviation emissions compared to other transport sectors, leaving aviation biofuels, also known as renewable jet fuels (RJFs), as currently the only commercialized option. Against this backdrop, in this thesis scenario analyses were conducted to produce biomass from EU+EFTA lands, project RJF yields from this biomass, and estimate emissions savings of these RJFs compared to petroleum jet fuel. Particular effort was devoted to identifying biomass, biofuels, and EU+EFTA lands that comply with RED-II criteria. The two RJF pathways selected were hydroprocessed esters and fatty acid (HEFA) conversion of Camelina sativa vegetable oil and Fischer-Tropsch (FT) synthesis of forestry residue lignocellulosic biomass. Over 117 million hectares in the EU+EFTA was identified as available for Camelina sativa cultivation, which could yield over 64 Mt of RJF each year, or 113 percent of the total jet fuel consumed in the EU+EFTA in 2017. Conversely, if 50 percent of the forestry residues generated as by-products from EU+EFTA roundwood harvesting operations in 2017 were extracted from harvest sites, 40 Mt of forestry residues would be available as biomass, which would yield almost 7.6 Mt of RJF annually (13% of 2017 jet fuel consumption). If all 144 million hectares of EU+EFTA forest lands deemed available for wood supply were logged, 1,772 Mt of forestry residues would be produced in total (at 50 percent extraction), which could result in almost 337 Mt of RJF, or 590% of the jet fuel consumed in the region in 2017. Hence, RJF can be feasibly produced from biomass from EU+EFTA lands, in amounts that meet or exceed the annual jet fuel consumption of the EU+EFTA, and in ways that meet or exceed RED-II sustainability criteria. However, the proportion of these RJF yields to total annual EU+EFTA jet fuel consumption will decrease over time as the number of flights and their resulting emissions increase. The two RJFs also emit 67 percent and 91 percent fewer GHG emissions, respectively, than petroleum-based jet fuel, showing them to be important tools for the EU to meet its 2030 renewables and emissions reductions targets. Producing the biomass feedstocks and RJFs in these quantities will require the EU to make serious decisions on land use trade-offs, such as whether livestock production is more important than biofuel production.

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Bevarandet av jordbruksmark i stadsnära lägen har under en längre tid, inom den fysiska planeringen, bortprioriteras. Omständigheter som pandemi, krig och klimatförändringar har gjort att frågor som berör jordbruksmark återigen har lyfts upp till ytan. Syftet med denna uppsats är därför att, utifrån en rådande samhällsutveckling, bidra med en ökad förståelse för vilka drivkrafter som ligger till grund för markanvändningsförändringar på jordbruksmark i Linköpings kommun. Detta eftersom jordbruksmark som tas i anspråk för bebyggelse och exploatering kan ses som problematisk ur både ett nationellt och internationellt livsmedelsförsörjningsperspektiv. Studiens empiri samlades in genom  kvalitativa intervjuer och analyserades sedan med hjälp av teori rörande drivkrafter och markanvändningsförändringar och tematisk analys. Resultatet av vår uppsats, med förankring i tidigare forskning, påvisar en problematik i hur jordbruksmark idag hanteras inom den fysiska planeringen. Detta eftersom ett flertal olika faktorer pekar på brister när det kommer till ansvar och förvaltande av jordbruksmark. / The preservation of agricultural land in locations close to the city has for a long time been de-prioritized in physical planning. Circumstances such as pandemic, war and climate change have meant that issues affecting agricultural land have once again been raised to the surface. The purpose of this study is therefore to, based on a contemporary context, contribute to an increased understanding of the driving forces underlying land use changes on agricultural land in Linköping municipality. This is because agricultural land that is used for development and exploitation can be seen as problematic from both a national and international food supply perspective. The study's empirical evidence was collected through qualitative interviews and then analyzed using theory regarding driving forces and land use changes and thematic analysis. The result of our essay, based on previous research, demonstrates a problem in how agricultural land is managed today within physical planning. This is because a number of different factors point to shortcomings when it comes to responsibility and management of agricultural land.

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Ziele der Arbeit sind die Bestimmung der dominanten Landnutzungsarten im Untersuchungsgebiet von Edd Al Fursan (Sudan) sowie die Kartierung und Analyse der Veränderungen der Landnutzung im Zeitraum 1972 bis 2008 mit Hilfe von multi-temporalen Satellitenbildern (Landsat MSS, TM und ETM sowie Terra ASTER). Des weiteren erfolgt eine Evaluierung des Einflusses von Veränderungen der Landnutzung auf die Lebensbedingungen der ländlichen Bevölkerung in Hinblick auf die Verfügbarkeit von Ressourcen mit Hilfe von quantitativen Untersuchungsmethoden. Um diese Aussagen treffen zu können, werden drei Methoden der Bestimmung von Veränderungen der Landnutzung angewandt, und zwar Post Classification Comparison (PCC), Change Vector Analysis (CVA) basierend auf Tasseled Cap Transformation (TCT) sowie Iteratively Reweighted Multivariate Alteration Detection (IR-MAD) mittels Maximum Autocorrelation Factor (MAF). Neben den fernerkundlichen Untersuchungen wurde eine sozio-ökonomische Feldstudie durchgeführt, die vorstrukturierte Fragenkataloge, Interviews und Gruppendiskussionen mit Personen in regionalen und lokalen Schlüsselpositionen und mit älteren Menschen durchgeführt. Fünf Klassen der Landnutzung und Landbedeckung ergeben sich aus einer Klassifikation der Satellitenbilder mit der Methode der größten Wahrscheinlichkeit (Maximum Likelihood), explizit die Klassen Grasland, Waldland, Brachland, bebautes und landwirtschaftlich nicht genutztes Land. Die Klassifikation schafft eine genaue Grundlage für die Kartierung, Quantifizierung und Analyse der Änderungen. Die Gesamtgenauigkeit der Flächenermittlung beträgt 83% für die Jahre 1972 und 1984, 85% für 1989, 87% für 1999 und 92% für 2008. Die Untersuchungen zeigen, dass die Post Classification Comparison (PCC) eine vollinhaltlich geeignete und leicht anzuwendende Methode der Flächenanalyse darstellt. Change Vector Analysis (CVA) beruhend auf Tasseled Cap Transformation (TCT) wird ebenfalls für die Kartierung und Bestimmung von Landnutzungsänderungen verwendet. Durch TCT wird der spektrale Bildinhalt in die Komponenten Greeness und Brightness transformiert sowie in dem dadurch neu definierten Koordinatensystem die CVA durchgeführt. Die Ergebnisse in Form von Vektoren der Veränderung mit messbarer Richtung und messbarem Ausmass der Flächendynamik beweisen, dass die Methode für die Kartierung von Vegetationsbedeckung und insbesondere von Entwaldung und Wiederbewaldung geeignet ist. Durch die Anwendung der Multivariate Alteration Detection (MAD) in Kombination mit dem Maximum Autocorrelation Factor (MAF) werden Veränderungen der Landnutzungsklassen während des betrachteten Zeitraumes visualisiert. Die Ergebnisse beweisen, dass die MAD für die Veränderungsanalyse in multi-spektralen Satellitenbildern sehr gut geeignet ist. Darüber hinaus wird nachgewiesen, dass die Kombination mit dem MAF die Ergebnisse der MAD entscheidend verbessern kann, da Rauschen und geringfügige Änderungen unterdrückt und signifikante Änderungen klarer herausgestellt und damit besser interpretierbar werden. Um die Ursachen für die Veränderungen der Landnutzung und den Einfluss dieser Änderungen auf die Lebensbedingungen der ländlichen Bevölkerung im Projektgebiet zu identifizieren, wurde eine Befragung mittels vorstrukturiertem Fragenkatalog, Interviews und Gruppengesprächen mit 100 GesprächspartnerInnen im Alter zwischen 42 und 65 Jahren in vier nach dem Zufallsprinizip ausgewählten Dörfern ausgeführt. Die Auswertung der sozio-ökonomischen Daten erlaubt die Extraktion der Faktoren, die Landnutzung und deren Änderung beeinflussen, und die zu bestimmten Auswirkungen dieser Änderungen auf die Lebensbedingungen in den Dörfern in Hinsicht auf die Verfügbarkeit von Natur-Ressourcen führen. Die Ergebnisse der Forschungsarbeiten zeigen, dass Fernerkundung und sozio-ökonomische Datenanalyse effizient verknüpft werden können, um anthropogene Einflüsse auf Art und Dynamik von Landnutzung sichtbar zu machen. In bezug auf die gegenständliche Zeitreihe wird durch die Untersuchungen bewiesen, dass zunehmende Bevölkerungszahlen im Gebiet von Edd Al-Fursan in direktem Wirkungszusammenhang mit Veränderungen der Landnutzung stehen.

Clay minerals and pedogenic metal (oxyhydr)oxides (hereafter termed ‛oxides’) significantly affect organic carbon (OC) storage and persistence in soils. Although it is known from laboratory experiments that minerals have a high variability in their reactivity, there is still a lack of fundamental knowledge how changing mineral composition under natural soil conditions works. The frequently used clay content (soil particles < 2-μm) or the dithionite-citrate-bicarbonate extractable Fe (Fed) content do not allow a mechanistic explanation of the function of clay minerals and pedogenic metal oxides. This is due to the fact that a similar relative mineral composition cannot necessarily be derived from the clay content. Therefore, the overall objective of the thesis was to identify the influence of defined mineralogical combinations on OC content, stock, and persistence under forest and cropland. The study examined highly weathered acidic soils (mainly Acrisols) from the East Usambara Mountains in NE Tanzania. The long-term weathering of geologically similar crystalline material under a humid tropical climate has produced a uniform spectrum of pedogenic minerals. Nonetheless, differences in the relative compositions of kaolinite (Al2Si2O5(OH)4), gibbsite (γ-Al(OH)3), goethite (α-FeOOH) and hematite (α-Fe2O3) were identified for the investigated soils. The soils were classified according to their mineralogical composition, based on the content of aluminous clay (kaolinite and gibbsite) and pedogenic Fe oxides (goethite and hematite). The applied approach generated a range of 149–434 g kg–1 for aluminous clay, and a range of 21–101 g kg–1 for Fed. A significant loss of 1.3 kg C m–2 was observed for the top 0–10 cm under cropland in comparison to the near-natural forests. Both the OC content and its persistence were significantly affected by the mineralogical composition in the soils. The ‛low clay‒high Fe’ combination had a similar or significantly higher OC content under both land uses, whereas significantly lower OC contents were measured for the other combinations under cropland. A more distinct effect of the mineral composition was measured for the mineral-associated OC (MAOC) content, which was determined by density fractionation and defined as OC associated with the heavy fraction (HF). A MAOC content of 37.4 g C kg–1 was measured for the ‛low clay‒high Fe’ combination, while only 19.4 g C kg–1 was found for the ‛high clay‒high Fe’ combination under cropland in the 0–10 cm depth. The lower OC and MAOC contents were accompanied by a significantly higher content of soil particles < 2-μm for the latter combination. This clearly reveals that no causal relationship between the OC and MAOC contents with the clay content can be established unless the dominant mineral phases and their composition for the soil sample are known. Analysis of the soils in the mineralogical combinations showed that with similar mineralogy, the Fed / aluminous clay ratio can be used as a metric to evaluate OC and MAOC contents and the persistence against land-use change. No significant changes were measured in the investigated soils under land-use change from forest to cropland for ratio values between 0.44 and 0.56. Results from a conducted incubation experiment and chemical oxidation of mineral-bound OC supported this result. The separation of the HF material in defined grain-size fractions along the respective mineralogical combinations revealed that the siltHF and clayHF fractions make an almost identical contribution to the total MAOC storage under undisturbed soil conditions. Thus, the MAOC content of the entire HF is mainly explained by the different mass of the grain-sizes fractions. Of particular note is the variable effect of land-use change on MAOC contents in the siltHF and clayHF fractions. While the MAOC content of the clayHF fraction showed little variation between land uses, the MAOC content of the siltHF fraction tracked the contents of the entire HF fraction along the mineralogical combinations. This result implies that small microaggregates / mineral-clusters (< 63-μm) are modified in their properties by changing mineral composition, which has a direct impact on the persistence of MAOC. Soil structure analysis revealed a high amount of very stable macroaggregates of the soils along the mineralogical combinations with small, but significant differences under both land uses. The results showed that an aluminous clay content of > 250 g kg–1 combined with Fed content of < 60 g kg–1 (‛high clay‒low Fe’) had a significantly positive effect on macroaggregation. The opposite combination (‛low clay‒high Fe’) caused a significant decrease in aggregates > 4 mm under cropland, which, however, was not associated with a significant decrease of the aggregate related OC content. Thus, the macroaggregation was influenced by the mineralogical combinations, but this had no significant effect on the related OC content. Rather, it becomes clear that interactions between minerals were particularly important in mineral clusters > 2-μm and < 63-μm, which determined the significant impact on the total (MA)OC content along the mineralogical combinations. Further studies can follow this trajectory to extend the mechanistic understanding of OC and MAOC content and persistence for highly weathered soils in the humid tropics.:1. General introduction 1.1 Soils of the humid tropics and their dominant mineral phases 1.2 Influence of mineralogy on the formation of mineral-associated OM in highly weathered soils of the humid tropics 1.3 Aggregation in weathered soils of the humid tropics: formation and associated organic carbon content 1.5 Scientific goals, main objectives, and hypotheses 2. Methodology 2.1 Characterization of the study area and the sampling strategy 2.2 Analyses to characterize mineral phases, MAOC and aggregation of the selected mineralogical combinations 2.3 Data set and applied statistical methods 3. General results and discussion 3.1 Soil mineralogical properties of the selected aluminous clay and pedogenic Fe oxide combinations 3.2 Basic considerations on bulk OC stocks and effect of mineralogical combinations on bulk OC and MAOC content and persistence 3.3 Effect of mineralogy on aggregation and aggregate-related OC contents 4. Conclusion 5. References Part II – Scientific publications 1. Impact of land use on soil organic carbon stocks in the humid tropics of NE Tanzania 1.0 Abstract 1.1 Introduction 1.2 Material and Methods 1.2.1 Study area 1.2.2 Description of the investigated land uses 1.2.3 Sampling, processing and analysis of soil 1.3 Results 1.3.1 Soil characterization 1.3.2 Content and stocks of SOC to 100 cm depth (soil profile approach) 1.3.3 SOC stocks of diagnostic soil horizons compared to fixed depth increments (satellite approach) 1.3.4 Content of clay, dithionite- and oxalate-extractable Fe and Al, and relationships to SOC content 1.4. Discussion 1.4.1 Impacts of land use on SOC stocks and potential controls of SOC stabilization 1.4.2 Effects of sampling schemes on the analysis of SOC stocks 1.5 Conclusions 1.6 References 2. Iron oxides and aluminous clays selectively control soil carbon contents and stability in the humid tropics 2.0 Abstract 2.1 Introduction 2.2 Results and Discussion 2.2.1 Mineralogical and geochemical properties of soil mineralogical combinations 2.2.2 Dependence of bulk soil carbon on aluminous clay and pedogenic Fe oxides 2.2.3 Effects of aluminous clay and pedogenic Fe oxides on mineral-associated carbon 2.2.5 Chemical and biological resistance of bulk and mineral-associated carbon 2.3 Implications 2.4. Methods 2.4.1 Study area and soil sampling 2.4.2 Basic soil properties 2.4.3 Density fractionation 2.4.4 Aluminous clay and pedogenic Fe oxide contents 2.4.5 Total element contents and weathering indicators 2.4.6 X-ray diffraction (XRD) 2.4.7 Mössbauer spectroscopy 2.4.8 Specific surface area (SSA) 2.4.9 13C Nuclear Magnetic Resonance Spectroscopy 2.4.10 Wet chemical oxidation and soil respiration 2.4.11 Statistics and calculations 2.5 References 2.6 Supplementary material 3. Aluminous clay and pedogenic Fe oxides modulate aggregation and related carbon contents in soils of the humid tropics 3.0 Abstract 3.1 Introduction 3.2 Material and methods 3.2.1 Study area and soil sampling 3.2.2 Soil analyses 3.2.2.1 Basic soil properties and terminology of selected mineralogical combinations 3.2.2.2 Aggregate size distribution and aggregate stability 3.2.2.3 Statistics and calculations 3.3 Results 3.3.1 Mineralogical composition and general soil properties 3.3.2 Aggregate size distribution 3.3.3 Aggregate stability 3.3.4 Organic carbon in soils and aggregate size fractions 3.4 Discussion 3.4.1 Aggregation and aggregate stability as controlled by aluminous clay and pedogenic Fe oxides 3.4.2 Importance of aggregation for OC persistence – effects of aluminous clay and pedogenic Fe oxides 3.5 Conclusions 3.6 References 3.7 Supplementary material 4. Appendix Erklärung zur Eröffnung des Promotionsverfahrens