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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Heavy Metal Uptake by Burrowing Mayflies in Western Lake Erie

Opfer, Sarah E. 29 July 2008 (has links)
No description available.
12

Conservação e evolução : da ecologia populacional a políticas públicas /

Leles, Bruno Pereira January 2019 (has links)
Orientador: Marina Corrêa Côrtes / Resumo: A fragmentação dos ambientes naturais pode gerar consequências negativas para a diversidade genética, a evolução e a conservação da biodiversidade. Esses efeitos podem se tornar ameaças à relevância dos ecossistemas para conservação da biodiversidade ao longo prazo e podem impulsionar a ocorrência de fenômenos evolutivos como a adaptação local em populações isoladas. Consequências negativas resultantes da fragmentação podem ser amplificadas por outras pressões negativas comuns em ambientes isolados, incluindo a poluição por metais pesados. A primeira parte desta tese avalia importantes mecanismos evolutivos que promovem a adaptação de plantas a solos contaminados por metais pesados. Informações sobre ecologia populacional, genômica e identificação de genes importantes para adaptação à alta concentração de elementos tóxicos, incluindo Fe, Pb, Cu, Al e Zn, foram usadas para testar mecanismos evolutivos. O estudo revela estratégias ecológicas e genes importantes para o crescimento de Cattleya liliputana em solos contaminados. Melhores ferramentas para a gestão da paisagem e maior integração de áreas protegidas e paisagens produtivas são importantes para reverter a tendência global de fragmentação e uso insustentável dos recursos naturais. A segunda parte da tese fornece ferramentas e análises para promover a conectividade, a integração e o manejo efetivo da paisagem. No segundo capítulo, uma ferramenta de análise espacial de fácil utilização para apoiar projetos com objetivo de ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The fragmentation of natural environments has pervasive consequences to genetic diversity, evolution and the conservation of biodiversity. These effects are important threats to the long-term relevance of ecosystems, and may drive evolutionary responses such as the local adaptation of isolated populations. Negative consequences resulting from fragmentation can be amplified by other common negative pressures in isolated environments, including pollution by heavy metals. Species that survive after contamination play an important role for restoration but face strong selective pressure for adaptation to the contaminants within an isolated environment. The first part of the thesis shed light on important evolutionary mechanisms that drive plant adaptation to soils contaminated by heavy metals. Information regarding population ecology, genomics, and identification of important genes for adaptation to the high concentration of toxic elements, including Fe, Pb, Cu, Al and Zn were used to test major evolutionary mechanisms. The study revealed ecological strategies and genes important for Cattleya liliputana adaptation to contaminated soils. Better tools for landscape management and enhanced integration of protected areas and production landscapes are important strategies to counter the global trend on fragmentation and unsustainable use of natural resources. The second part of the thesis provides tools and analysis to promote connectivity, integration and effective landscape managemen... (Complete abstract click electronic access below) / Doutor
13

Assessment of heavy metal contamination and restoration of soil food web structural complexity in urban vacant lots in two post-industrial cities

Sharma, Kuhuk 04 November 2014 (has links)
No description available.
14

Removal of hexavalent chromium in wastewater using granular ferric hydroxides

Lovell, Jessica, Levin, Sandra January 2015 (has links)
This study took place in Malawi, south eastern Africa. Metal contamination of water and soil is a threat to the environment and human health and is a serious concern in many countries including Malawi. Blantyre is the city of commerce where most of the industry is located along the banks of the main rivers. Some of the industries produce wastewater, which due to poor access to wastewater treatment plants, is discharged without treatment into the environment. A match factory in Blantyre uses chromium as a colouring agent for match heads and very high concentrations of chromium(VI) have been measured downstream the factory with concentrations up to 56 mg/l, which is much higher than the WHO guidelines of 0.05 mg/l.  Chromium(VI) mainly occurs as chromate CrO42- and dichromate Cr2O72- ions. They are both toxic and carcinogenic and can cause mutations and chromosomal aberrations.   The aim of the study was to evaluate the efficiency of Granular Ferric Hydroxide (GFH) in adsorbing and removing chromium from an aqueous phase. Wastewater was collected from the match factory and by optimizing relevant parameters the removal efficiency was maximized. The parameters optimized were pH, dosage and contact time and the effect of initial concentration. After respective experiment, all samples were analysed for chromium using microwave plasma atomic emission spectroscopy (MP-AES).   The optimum pH was chosen to 8.0, the dosage to 17.4 g GFH/l and the contact time to 2 hours for a 95% removal of total chromium in undiluted wastewater. The removal efficiency of the GFH was 2.84 mg Cr/g GFH. To implement wastewater purification with GFH a number of practical issues have to be taken into consideration. Above all, a sufficient stirring method has to be devised as the removal efficiency is much affected by improper stirring. / Denna studie genomfördes i Malawi, sydöstra Afrika. Metallföroreningar i vatten och mark är ett stort problem i många länder, inklusive Malawi. Landets centrum för industri och handel ligger i Blantyre där de flesta av industrierna ligger längs med floderna. En del industrier genererar utsläppsvatten och på grund av dålig tillgång till vattenreningsteknik och vattenreningsanläggningar släpps mycket av det förorenade vattnet obehandlat ut i naturen. En tändsticksfabrik i Blantyre använder kromsalter för att färga tändstickshuvudena röda och höga koncentrationer av sexvärt krom har uppmätts nedströms fabriken. De uppmätta koncentrationerna var upp till 56 mg/l vilket är betydligt högre än WHO:s riktvärde på 0,05 mg/l. Sexvärt krom förekommer som kromat CrO42- och dikromat Cr2O72- joner vilka båda är mycket toxiska och cancerframkallande och därmed ett hot mot miljö och människor. Syftet med studien var att undersöka om granulära järnoxider (GFH) kunde användas som en adsorbent för att rena utsläppsvatten från kromater. Utsläppsvatten hämtades från tändsticksfabriken och genom att optimera relevanta parametrar kunde GFHns adsorbtionseffektivitet maximeras. Parametrarna som optimerades var pH, dos, kontakttid och initialkoncentration. Efter respektive experiment mättes kromkoncentrationen med mikrovågsplasma atomemissionsspektroskopi (MP-AES) Det optimala pH-värdet valdes till 8.0, dosen till 17.4 g GFH/l med en kontakttid på 2 timmar för en 95.3% reningsgrad på outspätt utsläppsvatten. Adsorptionseffektiviteten på GFHn var 2.84 mg Cr/g GFH. För att implementera vattenrening med GFH behöver flera praktiska aspekter tas med i beaktning. Framförallt är det viktigt med en bra omrörning för att GFHn ska kunna adsorbera effektivt.
15

Fungos promotores do crescimento vegetal e da fitorremediação de metais pesados em combinação com biochar / Fungi promoting plant growth and phytoremediation of heavy metals in combination with biochar

Farias, Christyan Paiva 27 February 2018 (has links)
A busca por medidas sustentáveis para melhorar e suprir a demanda por alimentos que o crescimento populacional exige, aliado a escassez de terras produtivas, além do acúmulo excessivo de metais no ambiente devido a atividades como mineração e aplicação de fertilizantes no solo, foram as duas problemáticas que motivaram o presente estudo. O uso de fungos promotores do crescimento vegetal: Beauveria bassiana, Metarhizium anisopliae, Pochonia chlamydosporia, Purpureocillium lilacinum e Trichoderma asperella, pode tanto vir a influenciar o aumento da produtividade como potencializar a fitorremediação de metais pesados no solo. Esses fatos são explicados pela capacidade do consórcio fúngico de sintetizar e induzir as plantas a produzir fitohormônios direcionados para o melhor desenvolvimento das raízes do hospedeiro. O maior desenvolvimento de raízes pode estimular a fitoextração de metais do solo e conferir tolerância das plantas à contaminação. Na intenção de avaliar a influência dos fungos no desenvolvimento das plantas, foram realizados tratamentos das sementes de soja e milho e aplicação na parte aérea da cultura da cana-de-açúcar. Já para analisar a influência desses organismos no processo de fitorremediação de Cu, Zn e Mn em colunas de solos cultivados com Jacaranda mimosifolia D. Don, os fungos foram inoculados no solo e na parte aérea das plantas. Todos os tratamentos tiveram 6 repetições e suas médias foram submetidas à análise de variância e teste de média ao nível de 5% de probabilidade. O consórcio fúngico condicionou o crescimento de raízes de soja e milho, aumentou a colonização micorrízica arbuscular em soja e cana-de-açúcar. No jacarandá, os fungos melhoraram o desenvolvimento de raízes e parte aérea, maior acúmulo de Mn e Zn na planta, melhor translocação de Mn e Zn das raízes para a parte aérea, além de diminuir o estresse fisiológico. Além disso, a aplicação conjunta de fungos e biochar nas mudas proporciona proteção à sua atividade fotossintética e reduz o risco ambiental de contaminação por metais por diminuir o total de Cu, Mn e Zn lixiviado. O biochar foi adquirido por meio da pirólise lenta do resíduo do beneficiamento da madeira de eucalipto e aplicado superficialmente no solo. Com isso, esse estudo mostrou que os fungos utilizados apresentam potencial para colaborar com o aumento da produtividade de culturas comerciais e colaborar com a melhoria na remediação de solos contaminados com íons metálicos. / The search for sustainable measures to improve and meet the demand for food that population growth requires, combined with the scarcity of productive land, in addition to the excessive accumulation of metals in the environment due to activities such as mining and application of soil fertilizers, were the two problems that motivated the present study. The use of fungi plant growth promoters: Beauveria bassiana, Metarhizium anisopliae, Pochonia chlamydosporia, Purpureocillium lilacinum and Trichoderma asperella can both influence on increasing productivity as the phytoremediation of heavy metals in the soil. These facts are explained by the capacity of the fungal Consortium to synthesize and induce plants to produce phytohormone targeted for the better development of the roots of the host. The further development of roots can stimulate phytoextraction of metals from the soil and give plants tolerance to contamination. In order to evaluate the influence of fungi on the development of plants, were done seed treatments of soybeans and corn and application in aerial part of the culture of sugar cane. To analyze the influence of these organisms in the process of phytoremediation of Cu, Zn and Mn in soil columns cultivated with Jacaranda mimosifolia D. Don, fungi were inoculated in soil and aerial part of plants. All treatments had 6 reptitions and their averages were subjected to analysis of variance and average test at 5% probability. The fungal consortium has conditioned the growth of roots of soybeans and corn, mycorrhizal colonization increased in soybeans and sugar cane. In jacarandá, fungi have improved the development of roots and shoots, greater accumulation of Mn and Zn in plant, best of Mn and Zn translocation from roots to shoots, in addition to decrease physiological stress. In addition, the joint application of fungus and biochar in seedlings provides protection to photosynthetic activity and reduces the risk of environmental contamination by metals by decreasing the amount of Cu, Mn and Zn leached. The biochar was acquired through the slow pyrolysis of the eucalyptus wood processing residue and applied superficially to the soil. With that, this study showed that fungi used present potential to contribute to the increased productivity of commercial crops and contribute to the improvement in the remediation of soils contaminated with metal ions. / Dissertação (Mestrado)

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