926 resultados para Recycling textiles
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This paper presents the results of a field experiment conducted in Kerala, South India, to test the effectiveness of coir geotextiles for embankment protection. The results reveal that treatment with geotextile in combination with grass is an effective eco-hydrological measure to protect steep slopes from erosion. In the context of sustainable watershed management, coir is a cheap and locally available material that can be used to strengthen traditional earthen bunds or protect the banks of village ponds from erosion. Particularly in developing countries, where coir is abundantly available and textiles can be produced by small-scale industry, this is an attractive alternative for conventional methods. The paper analyses the performance of different treatments with regard to soil moisture content, protection against erosion and biomass production
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High styrene rubber ionomers were prepared by sulfonating styrene–butadiene rubber of high styrene content (high styrene rubber) in 1,2-dichloroethane using acetyl sulfate reagent, followed by neutralization of the precursor acids using methanolic zinc acetate. The ionomers were characterized using X-ray fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), dynamic mechanical analysis (DMA), and also by the evaluation of mechanical properties. The FTIR studies of the ionomer reveal that the sulfonate groups are attached to the benzene ring. The NMR spectra give credence to this observation. Results of DMA show an ionic transition (Ti) in addition to glass–rubber transition (Tg). Incorporation of ionic groups results in improved mechanical properties as well as retention of properties after three cycles of processing
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Expanded polystyrene (EPS) constitutes a considerable part of thermoplastic waste in the environment in terms of volume. In this study, this waste material has been utilized for blending with silica-reinforced natural rubber (NR). The NR/EPS (35/5) blends were prepared by melt mixing in a Brabender Plasticorder. Since NR and EPS are incompatible and immiscible a method has been devised to improve compatibility. For this, EPS and NR were initially grafted with maleic anhydride (MA) using dicumyl peroxide (DCP) to give a graft copolymer. Grafting was confirmed by Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy. This grafted blend was subsequently blended with more of NR during mill compounding. Morphological studies using Scanning Electron Microscopy (SEM) showed better dispersion of EPS in the compatibilized blend compared to the noncompatibilized blend. By this technique, the tensile strength, elongation at break, modulus, tear strength, compression set and hardness of the blend were found to be either at par with or better than that of virgin silica filled NR compound. It is also noted that the thermal properties of the blends are equivalent with that of virgin NR. The study establishes the potential of this method for utilising waste EPS
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Among the decapod crustaceans, brachyuran crabs or the true crabs occupy a very significant position due to their ecological and economic value. Crabs support a sustenance fishery in India, even though their present status is not comparable to that of shrimps and lobsters. They are of great demand in the domestic market as well as in the foreign markets. In addition to this, brachyuran crabs are of great ecological importance. They form the conspicuous members of the mangrove ecosystems and play a significant role in detritus formation, nutrient recycling and dynamics of the ecosystem. Considering all these factors, crabs are often considered to be the keystone species of the mangrove ecosystem. Though several works have been undertaken on brachyuran crabs world –wide as well as within the country, reports on the brachyuran crabs of Kerala waters are very scanty. Most of the studies done on brachyuran fauna were from the east coast of India and a very few works from the west coast. Among the edible crabs, mud crabs belonging to genus Scylla forms the most important due to their large size and taste. They are being exported on a large scale to the foreign markets like Singapore, Malaysia and Hong Kong. Kerala is the biggest supplier of live mud crabs and Chennai is the major centre of live mud crab export. However, there exists considerable confusion regarding the identification of mud crabs because of the subtle morphological differences between the species.In this context, an extensive study was undertaken on the brachyuran fauna of Cochin Backwaters, Kerala, India, to have a basic knowledge on their diversity, habitat preference and systematics. The study provides an attempt to resolve the confusion pertaining in the species identification of mud crabs belonging to Genus Scylla. Diversity study revealed the occurrence of 23 species of brachyuran crabs belonging to 16 genera and 8 families in the study area Cochin Backwaters. Among the families, the highest number of species was recorded from Family Portunidae .Among the 23 crab species enlisted from the Cochin backwaters, 5 species are of commercial importance and contribute a major share to the crustacean fishery of the Cochin region. It was observed that, the Cochin backwaters are invaded by certain marine migrant species during the Post monsoon and Pre monsoon periods and they are found to disappear with the onset of monsoon. The study reports the occurrence of the ‘herring bow crab’ Varuna litterata in the Cochin backwaters for the first time. Ecological studies showed that the substratum characteristics influence the occurrence, distribution and abundance of crabs in the sampling stations rather than water quality parameters. The variables which affected the crab distribution the most were Salinity, moisture content in the sediment, organic carbon and the sediment texture. Besides the water and sediment quality parameters, the most important factor influencing the distribution of crabs is the presence of mangroves. The study also revealed that most of the crabs encountered from the study area preferred a muddy substratum, with high organic carbon content and high moisture content. In the present study, an identification key is presented for the brachyuran crabs occurring along the study area the Cochin backwaters and the associated mangrove patches, taking into account the morphological characters coupled with the structure of third maxillipeds, first pleopods of males and the shape of male abdomen. Morphological examination indicated the existence of a morphotype which is comparable with the morphological features of S. tranquebarica, the morphometric study and the molecular analyses confirmed the non existence of S. tranquebarica in the Cochin backwaters.
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From the early stages of the twentieth century, polyaniline (PANI), a well-known and extensively studied conducting polymer has captured the attention of scientific community owing to its interesting electrical and optical properties. Starting from its structural properties, to the currently pursued optical, electrical and electrochemical properties, extensive investigations on pure PANI and its composites are still much relevant to explore its potentialities to the maximum extent. The synthesis of highly crystalline PANI films with ordered structure and high electrical conductivity has not been pursued in depth yet. Recently, nanostructured PANI and the nanocomposites of PANI have attracted a great deal of research attention owing to the possibilities of applications in optical switching devices, optoelectronics and energy storage devices. The work presented in the thesis is centered around the realization of highly conducting and structurally ordered PANI and its composites for applications mainly in the areas of nonlinear optics and electrochemical energy storage. Out of the vast variety of application fields of PANI, these two areas are specifically selected for the present studies, because of the following observations. The non-linear optical properties and the energy storing properties of PANI depend quite sensitively on the extent of conjugation of the polymer structure, the type and concentration of the dopants added and the type and size of the nano particles selected for making the nanocomposites. The first phase of the work is devoted to the synthesis of highly ordered and conducting films of PANI doped with various dopants and the structural, morphological and electrical characterization followed by the synthesis of metal nanoparticles incorporated PANI samples and the detailed optical characterization in the linear and nonlinear regimes. The second phase of the work comprises the investigations on the prospects of PANI in realizing polymer based rechargeable lithium ion cells with the inherent structural flexibility of polymer systems and environmental safety and stability. Secondary battery systems have become an inevitable part of daily life. They can be found in most of the portable electronic gadgets and recently they have started powering automobiles, although the power generated is low. The efficient storage of electrical energy generated from solar cells is achieved by using suitable secondary battery systems. The development of rechargeable battery systems having excellent charge storage capacity, cyclability, environmental friendliness and flexibility has yet to be realized in practice. Rechargeable Li-ion cells employing cathode active materials like LiCoO2, LiMn2O4, LiFePO4 have got remarkable charge storage capacity with least charge leakage when not in use. However, material toxicity, chance of cell explosion and lack of effective cell recycling mechanism pose significant risk factors which are to be addressed seriously. These cells also lack flexibility in their design due to the structural characteristics of the electrode materials. Global research is directed towards identifying new class of electrode materials with less risk factors and better structural stability and flexibility. Polymer based electrode materials with inherent flexibility, stability and eco-friendliness can be a suitable choice. One of the prime drawbacks of polymer based cathode materials is the low electronic conductivity. Hence the real task with this class of materials is to get better electronic conductivity with good electrical storage capability. Electronic conductivity can be enhanced by using proper dopants. In the designing of rechargeable Li-ion cells with polymer based cathode active materials, the key issue is to identify the optimum lithiation of the polymer cathode which can ensure the highest electronic conductivity and specific charge capacity possible The development of conducting polymer based rechargeable Li-ion cells with high specific capacity and excellent cycling characteristics is a highly competitive area among research and development groups, worldwide. Polymer based rechargeable batteries are specifically attractive due to the environmentally benign nature and the possible constructional flexibility they offer. Among polymers having electrical transport properties suitable for rechargeable battery applications, polyaniline is the most favoured one due to its tunable electrical conducting properties and the availability of cost effective precursor materials for its synthesis. The performance of a battery depends significantly on the characteristics of its integral parts, the cathode, anode and the electrolyte, which in turn depend on the materials used. Many research groups are involved in developing new electrode and electrolyte materials to enhance the overall performance efficiency of the battery. Currently explored electrolytes for Li ion battery applications are in liquid or gel form, which makes well-defined sealing essential. The use of solid electrolytes eliminates the need for containment of liquid electrolytes, which will certainly simplify the cell design and improve the safety and durability. The other advantages of polymer electrolytes include dimensional stability, safety and the ability to prevent lithium dendrite formation. One of the ultimate aims of the present work is to realize all solid state, flexible and environment friendly Li-ion cells with high specific capacity and excellent cycling stability. Part of the present work is hence focused on identifying good polymer based solid electrolytes essential for realizing all solid state polymer based Li ion cells.The present work is an attempt to study the versatile roles of polyaniline in two different fields of technological applications like nonlinear optics and energy storage. Conducting form of doped PANI films with good extent of crystallinity have been realized using a level surface assisted casting method in addition to the generally employed technique of spin coating. Metal nanoparticles embedded PANI offers a rich source for nonlinear optical studies and hence gold and silver nanoparticles have been used for making the nanocomposites in bulk and thin film forms. These PANI nanocomposites are found to exhibit quite dominant third order optical non-linearity. The highlight of these studies is the observation of the interesting phenomenon of the switching between saturable absorption (SA) and reverse saturable absorption (RSA) in the films of Ag/PANI and Au/PANI nanocomposites, which offers prospects of applications in optical switching. The investigations on the energy storage prospects of PANI were carried out on Li enriched PANI which was used as the cathode active material for assembling rechargeable Li-ion cells. For Li enrichment or Li doping of PANI, n-Butyllithium (n-BuLi) in hexanes was used. The Li doping as well as the Li-ion cell assembling were carried out in an argon filled glove box. Coin cells were assembled with Li doped PANI with different doping concentrations, as the cathode, LiPF6 as the electrolyte and Li metal as the anode. These coin cells are found to show reasonably good specific capacity around 22mAh/g and excellent cycling stability and coulombic efficiency around 99%. To improve the specific capacity, composites of Li doped PANI with inorganic cathode active materials like LiFePO4 and LiMn2O4 were synthesized and coin cells were assembled as mentioned earlier to assess the electrochemical capability. The cells assembled using the composite cathodes are found to show significant enhancement in specific capacity to around 40mAh/g. One of the other interesting observations is the complete blocking of the adverse effects of Jahn-Teller distortion, when the composite cathode, PANI-LiMn2O4 is used for assembling the Li-ion cells. This distortion is generally observed, near room temperature, when LiMn2O4 is used as the cathode, which significantly reduces the cycling stability of the cells.
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As a result of the drive towards waste-poor world and reserving the non-renewable materials, recycling the construction and demolition materials become very essential. Now reuse of the recycled concrete aggregate more than 4 mm in producing new concrete is allowed but with natural sand a fine aggregate while. While the sand portion that represent about 30\% to 60\% of the crushed demolition materials is disposed off. To perform this research, recycled concrete sand was produced in the laboratory while nine recycled sands produced from construction and demolitions materials and two sands from natural crushed limestone were delivered from three plants. Ten concrete mix designs representing the concrete exposition classes XC1, XC2, XF3 and XF4 according to European standard EN 206 were produced with partial and full replacement of natural sand by the different recycled sands. Bituminous mixtures achieving the requirements of base courses according to Germany standards and both base and binder courses according to Egyptian standards were produced with the recycled sands as a substitution to the natural sands. The mechanical properties and durability of concrete produced with the different recycled sands were investigated and analyzed. Also the volumetric analysis and Marshall test were performed hot bituminous mixtures produced with the recycled sands. According to the effect of replacement the natural sand by the different recycled sands on the concrete compressive strength and durability, the recycled sands were classified into three groups. The maximum allowable recycled sand that can be used in the different concrete exposition class was determined for each group. For the asphalt concrete mixes all the investigated recycled sands can be used in mixes for base and binder courses up to 21\% of the total aggregate mass.
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Judged by their negative nutrient balances, low soil cover and low productivity, the predominant agro-pastoral farming systems in the Sudano-Sahelian zone of West Africa are highly unsustainable for crop production intensification. With kaolinite as the main clay type, the cation exchange capacity of the soils in this region, often less than 1 cmol_c kg^-1 soil, depends heavily on the organic carbon (Corg) content. However, due to low carbon sequestration and to the microbe, termite and temperature-induced rapid turnover rates of organic material in the present land-use systems, Corg contents of the topsoil are very low, ranging between 1 and 8 g kg^-1 in most soils. For sustainable food production, the availability of phosphorus (P) and nitrogen (N) has to be increased considerably in combination with an improvement in soil physical properties. Therefore, the adoption of innovative management options that help to stop or even reverse the decline in Corg typically observed after cultivating bush or rangeland is of utmost importance. To maintain food production for a rapidly growing population, targeted applications of mineral fertilisers and the effective recycling of organic amendments as crop residues and manure are essential. Any increase in soil cover has large effects in reducing topsoil erosion by wind and water and favours the accumulation of wind-blown dust high in bases which in turn improves P availability. In the future decision support systems, based on GIS, modelling and simulation should be used to combine (i) available fertiliser response data from on-station and on-farm research, (ii) results on soil productivity restoration with the application of mineral and organic amendments and (iii) our present understanding of the cause-effect relationships governing the prevailing soil degradation processes. This will help to predict the effectiveness of regionally differentiated soil fertility management approaches to maintain or even increase soil Corg levels.
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Little is known about plant biodiversity, irrigation management and nutrient fluxes as criteria to assess the sustainability of traditional irrigation agriculture in eastern Arabia. Therefore interdisciplinary studies were conducted over 4 yrs on flood-irrigated fields dominated by wheat (Triticum spp.), alfalfa (Medicago sativa L.) and date palm (Phoenix dactylifera L.) in two mountain oases of northern Oman. In both oases wheat landraces consisted of varietal mixtures comprising T. aestivum and T. durum of which at least two botanical varieties were new to science. During irrigation cycles of 6-9 days on an alfalfa-planted soil, volumetric water contents ranged from 30-13%. For cropland, partial oasis balances (comprising inputs of manure, mineral fertilizers, N2-fixation and irrigation water, and outputs of harvested products) were similar for both oases, with per hectare annual surpluses of 131 kg N, 37 kg P and 84 kg K at Balad Seet and of 136 kg N, 16 kg P and 66 kg K at Maqta. Respective palm grove surpluses, in contrast were with 303 kg N, 38 kg P, and 173 kg K ha^-1 yr^-1 much higher at Balad Seet than with 84 kg N, 14 kg P and 91 kg K ha^-1 yr^-1 at Maqta. The results show that the sustainability of these irrigated landuse systems depends on a high quality of the irrigation water with low Na but high CaCO3, intensive recycling of manure and an elaborate terrace structure with a well tailored water management system that allows adequate drainage.
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Der Endocytoseweg in Dictyostelium verläuft über definierte endosomale Reifestadien. Dabei werden die reifenden Endosomen im letzten Stadium durch eine Schicht aus filamentösem Aktin umhüllt. Über die biologische Funktion dieser Aktin-Hülle ist derzeit wenig bekannt. Zum weiteren Erkenntnisgewinn sollten daher unterschiedliche Aktin-interagierende Proteine an die endosomale Aktin-Hülle dirigiert und die sich daraus ergebenden Folgen untersucht werden. Dabei wurde der in Drengk et al., 2003 beschriebene Ansatz aufgegriffen, in dem Proteine durch die Fusion an Vacuolin an die späte endosomale Membran transportiert wurden. Die endosomale Lokalisation von DAip1 bewirkte den vollständigen Verlust der endosomalen Aktin-Hülle, ohne dabei das restliche zelluläre Cytoskelett zu beeinträchtigen. Dabei wird die Depolymerisation vermutlich über die nachgewiesene Interaktion von DAip1 mit dem Aktin-depolymerisierenden Protein Cofilin bewirkt. Einhergehend damit trat eine Aggregation der betroffenen Kompartimente, eine Verzögerung des endocytotischen Transits, sowie eine verstärkte Retention lysosomaler Enzyme auf. Diese Ergebnisse ließen auf eine Funktion der endosomalen Aktin-Hülle als Fusionsinhibitor oder in der Regulation von Recycling-Prozessen an späten Endosomen schließen. Die Verlängerung der endosomalen Verweilzeit des den Arp2/3-Komplex negativ regulierenden Proteins Coronin bewirkte dagegen keine offensichtlichen Veränderungen in den betroffenen Zellen. Diese Beoachtung könnte ein Indiz dafür sein, dass nach der Ausbildung der Aktin-Hülle keine weiteren essentiellen Arp2/3-abhängigen mehr an der endosomalen Membran auftreten. Die endosomale Lokalisation des Aktin-Crosslinkers ABP34 induzierte ebenfalls keine Abweichungen vom Wildtyp-Verhalten. Hierbei besteht allerdings die Möglichkeit, dass die Aktivität des Proteins durch die bereits zuvor beschriebene Calcium-Sensitivität beeintächtigt vorliegt. Eine Verstärkung der endosomalen Hülle konnte trotz der Verwendung unterschiedlicher Ansätze nicht hervorgerufen werden. Offensichtlich wirkt die zusätzliche Expression zentraler Regulatoren der Aktin-Polymerisation in der Zelle cytotoxisch. Die Bindung von VASP an die endosomale Membran bewirkte in den Zellen die Ausbildung voluminöser, cytoplasmatischer „Aktin-Bälle“. Diese riefen in den betroffenen Zellen Defekte in unterschiedlichen Aktin-abhängigen Prozessen, wie der Phago- und Pinocytose, sowie der Cytokinese hervor. Dabei gehen die beobachteten Veränderungen vermutlich auf die nachgewiesene Störung im Gleichgewicht zwischen G- und F-Aktin zurück. Obwohl die Aktin-Bälle an der endosomalen Membran entstehen, weisen sie nach vollendeter Entstehung keine inneren oder äußeren Membranen mehr auf und nehmen nicht mehr aktiv am endocytotischen Geschehen teil. Die nähere Charakterisierung offenbarte große Ähnlichkeit zu den mit unterschiedlichen neurodegenerativen Erkrankungen assoziierten Hirano-Bodies. Über das beobachtbare Lokalisationsverhalten der unterschiedlichen im ersten Teil der Arbeit eingesetzten Vacuolin-Hybridproteine ließ sich die Stärke der Lokalisationsinformationen der fusionierten Aktin-interagierenden Proteine miteinander vergleichen. Dies wurde verwendet, um die einzelnen Proteine gemäß ihres Targeting-Potenzials hierarchisch anzuordnen. Im zweiten Teil der Arbeit wurden dieser Hierarchie die beiden cytoplasmatischen Targeting-Signale für Peroxisomen (PTS1) und den Zellkern (SV40-NLS) hinzugefügt. Der vorgenommene Vergleich dieser in vivo gewonnen Daten aus Dictyostelium mit unterschiedlichen in vitro-Bindungsstudien mit homologen Proteinen anderer Organismen zeigte eine erstaunlich gute Übereinstimmung. Diese Beobachtung lässt auf vergleichbare Targeting-Affinitäten innerhalb der Eukaryoten schließen und belegt, dass die zelluläre Lokalisation eines Proteins relativ sicher anhand der in ihm vorhandenen Bindungs-Affinitäten vorhergesagt werden kann. Durch die Kombination der in vivo- und in vitro-Daten war es auch ohne Kenntnis des Oligomerisierungsgrades und des Interaktionspartners erstmals möglich, die Bindungsstärke von Vacuolin an der endosomalen Membran auf einen definierten Bereich einzugrenzen.
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Prinzipien und Strategien der Nachhaltigkeit spielen auch in der zeitgenössischen Landschaftsarchitektur eine immer bedeutendere Rolle. Vor dem Hintergrund der ansteigenden Zahl an postindustriellen Flächen in Deutschland und der gleichzeitigen Zielsetzung, im Sinne einer nachhaltigen gesellschaftlichen Entwicklung die Flächeninanspruchnahme zu reduzieren, entsteht die Forderung, die Altindustrie-Areale in eine nachhaltige neue Nutzung zu überführen und damit auch den Außenraum nachhaltig zu entwickeln. Dabei spielt die Integration der vorhandenen Strukturen wie Baukonstruktionen, Materialien und Vegetation eine bedeutende Rolle. Für den nachhaltigen Umgang mit den vorhandenen Elementen im Außenraum gibt es bisher keine systematisierten Anweisungen oder Handlungsrichtlinien. Die Arbeit schließt diese Lücke , indem sowohl grundsätzliche Nachhaltigkeitspotenziale in der Landschaftsarchitektur untersucht und definiert werden als auch die Anwendung der erarbeiteten Prinzipien auf den Umgang mit den besonderen Orten der Altindustrieflächen erfolgt. Ein Vorgehen im Sinne einer nachhaltigen Entwicklung des Außenraumes unter Einbeziehung der vorhandenen Elemente und Strukturen wird systematisiert und in Handlungsrichtlinien formuliert. Praxisnähe und Anwendbarkeit sind dabei wichtige Zielsetzungen. Um nicht nur die Relevanz der vorhandenen Strukturen für die ökonomische Dimension der Nachhaltigkeit zu untersuchen, wird im zweiten Teil der Arbeit die Frage nach der Bedeutung der vorhandenen Elemente für den ökonomischen Aspekt der Nachhaltigkeit gestellt und beantwortet. Dazu wird ein Beispielstandort einer ehemaligen Zeche im Ruhrgebiet ausgewählt. Für ein charakteristisches Teilareal mit zahlreichen vorhandenen Strukturen im Außenraum wie befestigten Flächen aus unterschiedlichen Materialien, Baukonstruktionen sowie Vegetation werden die Baukosten detailliert für verschiedene Szenarien - je nach Anteil von Wiederverwendung bzw. Neubau - kalkuliert und verglichen. In einem zweiten Schritt erfolgt die Kalkulation der Baukosten für die Szenarien bei Verwendung vorhandener recycelter Materialien. Im Ergebnis zeigt die Arbeit die Nachhaltigkeitspotenziale innovativer Landschaftsarchitektur systematisch und praxisbezogen auf - generell, wie auch für den speziellen Fall der postindustriellen Flächen. Die ökonomische Bedeutung der vorhandenen Substanz im Außenraum wird anhand eines konkreten Fallbeispiels untersucht, und es werden Aussagen zu Einsparungsmöglichkeiten durch die Integration der vorhandenen Strukturen sowie durch den Einsatz der recycelten vorhandenen Materialien getroffen. So können z.B. für bestimmte Kostengruppen Baukosten in einem Rahmen von bis zu 40 % bei Verwendung/Recycling der vorhandenen Bausubstanz eingespart werden. Die Ergebnisse der Untersuchungen sind in praxisnaher Form präsentiert und stellen eine wichtige Entscheidungsgrundlage im Planungsprozess postindustrieller Nutzungen auf Altindustrieflächen dar.
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Recycling nutrients form sanitary wastes back into agricultural ecosystems offers an option to alleviate soil depletion in regions where the use of mineral fertiliser is limited. Exemplary nutrient and water cycling approaches, including collection, treatment and use of human urine, are established at Valley View University (VVU) in Greater Accra, Ghana. Concerns have been recently raised in regard to fate and impact of pharmaceutical residues in soils and interlinked environment. To evaluate in how far emerging knowledge can be transposed onto VVU, urban and rural environments in Greater Accra, spatial disease occurrence and drug consumption patterns were studied. Malaria has been found to represent the most severe health burden in Ghana, but there is also a high prevalence of infectious diseases. Drugs consumed in great quantities and in respect to their residual loads potentially problematic in the environment belong to therapeutic groups of: antibiotics, analgesics, drugs for diabetes, antimalarials, cardiovascular drugs and anthelmintics. Drug consumption revealed to be highest in urban and lowest in rural areas. At VVU the range of consumed drugs is comparable to urban areas except for the negligible use of diabetes and cardiovascular medication as well as contraceptives.