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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.
1

Structure and functions of the ventral tube of the clover springtail Sminthurus viridis (Collembola Sminthuridae)

Chen, C-G., Chen, T., Hua, B-Z., Wan, Tao Ruan 29 January 2019 (has links)
Yes / Springtails (Collembola) are unique in Hexapoda for bearing a ventral tube (collophore) on the first abdominal segment. Although numerous studies have been conducted on the functions of the ventral tube, its fine structure has not been thoroughly elucidated to date. In this paper, we observed the jumping behavior of the clover springtail Sminthurus viridis (Linnaeus, 1758) and dissected the ventral tube using light microscopy to elucidate the fine structure and the possible function of the ventral tube. The results show that a pair of eversible vesicles can be extended from the apical opening of the ventral tube. The eversible vesicles are furnished with numerous small papillae, and can be divided into a basal part and a distal part. The eversible vesicles have a central lumen connected to the tiny papillae and leading to the body cavity. The eversible vesicles can reach any part of the body, and may serve as following functions: (a) absorbing moisture; (b) uptaking water; (c) cleaning the body surface; and (d) fastening the body on a smooth surface.
2

The effects of multi-walled carbon nanotube exposure on soil organisms

Martin, William J. January 2012 (has links)
With the rapid proliferation of carbon nanotube technologies and consumer products comes a need to research the toxicological and ecotoxicological effects of these materials. This research attempted to develop a baseline knowledge of the effects of bulk, unmodified multi-walled carbon nanotubes on commonly studied soil toxicology test organisms: earthworms, springtails, and agricultural plants. In order to minimize confounding factors in the study, a slurry composed of bulk multi-walled carbon nanotubes, silica sand, and water was used to amend test soil without the use of surfactants or functionalization. Analysis of data produced by these experiments showed no significant trends resulting from the exposure of the test organisms to artificial soil amended by the multi- walled carbon nanotube slurry. It was observed, however that carbon nanotubes accumulated in the gut of the earthworm Eisenia andrei and were expelled as castings in the test soil.
3

The effects of multi-walled carbon nanotube exposure on soil organisms

Martin, William J. January 2012 (has links)
With the rapid proliferation of carbon nanotube technologies and consumer products comes a need to research the toxicological and ecotoxicological effects of these materials. This research attempted to develop a baseline knowledge of the effects of bulk, unmodified multi-walled carbon nanotubes on commonly studied soil toxicology test organisms: earthworms, springtails, and agricultural plants. In order to minimize confounding factors in the study, a slurry composed of bulk multi-walled carbon nanotubes, silica sand, and water was used to amend test soil without the use of surfactants or functionalization. Analysis of data produced by these experiments showed no significant trends resulting from the exposure of the test organisms to artificial soil amended by the multi- walled carbon nanotube slurry. It was observed, however that carbon nanotubes accumulated in the gut of the earthworm Eisenia andrei and were expelled as castings in the test soil.
4

ATRIBUTOS BIOLÓGICOS E FÍSICOS DO SOLO COM O USO DE BIOFERTILIZANTE / ATTRIBUTES BIOLOGICAL AND SOIL PHYSICAL WITH THE USE BIOFERTILIZER

Bertollo, Gilvan Moisés 27 February 2015 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The use of biofertilizers has been effective alternative to proper disposal of waste. However, addition of organic waste culture systems can influence the soil biota, microorganisms, and the physical properties of the soil. The objective of this study was to determine the influence of biofertilizer application in fauna and soil physical properties. The study was conducted in four experiments. The first consisted of the evaluation of soil fauna with the use of biofertilizers bovine in a randomized design with factorial arrangement 5 x 12, five fertilization (0 (no biofertilizer control), 150, 300, 450 and 600 L ha-1 biofertilizer bovine), twelve months, with four replications. The second study was analyzed the multiplication of springtails in laboratory conditions under different crop residues and doses of bovine biofertilizer. Another experiment was conducted to evaluate the microbiological changes in soil submitted to fertilization with bovine biofertilizer with randomized block experimental design and, finally, we evaluated the physical properties of an Oxisol submitted to doses of bovine biofertilizer. It was observed that the bovine biofertilizer not interfere in the analyzed biological variables and for the orders, all varied over the time of collection except for Lepidoptera. In reproduction of Collembola laboratory, bovine biofertilizer favors until the estimated dose of 266 L ha-1 and crop residues tested without the use of yeast favors the proliferation of Collembola. The activity of soil organisms is greater on the surface and the estimated dose of 298 L ha-1 bovine biofertilizer and the application of bovine biofertilizer only enabled the rise of evidence macroporosity and microporosity decreased when used doses up to 268 and 293 L ha-1, respectively, necessitating further studies to confirm these results. / O uso de biofertilizantes tem sido alternativa eficiente para descarte correto dos dejetos. Contudo, a adição de resíduos orgânicos em sistemas de cultivo pode influenciar a biota do solo, microrganismos e as propriedades físicas do solo. O objetivo deste trabalho foi determinar a influencia da aplicação biofertilizante sobre os organismos e propriedades físicas do solo. O trabalho foi desenvolvido em quatro experimentos. O primeiro constou da avaliação da fauna edáfica com o uso de biofertilizante bovino em delineamento experimental de blocos casualizados em arranjo fatorial 5 x 12, sendo cinco adubações (0 (controle sem biofertilizante), 150, 300, 450 e 600 L ha-1 de biofertilizante bovino), doze meses, com 4 repetições. O segundo trabalho foi analisado a multiplicação de colêmbolos em condições de laboratório submetidos a diferentes resíduos vegetais e doses de biofertilizante bovino. Outro experimento foi realizado para avaliar as alterações microbiológicas em solo submetido à adubação com biofertilizante bovino com delineamento experimental de blocos ao acaso e, por fim, foi avaliado as propriedades físicas de um Latossolo submetido a doses de biofertilizante bovino. Observou-se que o biofertilizante bovino não interfere nas variáveis biológicas analisadas e em relação as ordens, todas variaram ao longo da época de coleta com exceção da Lepidóptera. Na reprodução dos colêmbolos em laboratório, o biofertilizante bovino favorece até a dose estimada de 266 L ha-1 e os resíduos vegetais testados sem o uso de fermento biológico favorecem a multiplicação de colêmbolos. A atividade dos organismos do solo é maior na superfície e na dose estimada de 298 L ha-1 de biofertilizante bovino e a aplicação de biofertilizante bovino apenas possibilitou indícios de aumento da macroporosidade e diminuição da microporosidade quando utilizado doses de até 268 e 293 L ha-1, respectivamente, necessitando-se de mais estudos para confirmação destes resultados.
5

DISTRIBUIÇÃO E DIVERSIDADE ESPAÇO- TEMPORAL DA CLASSE COLLEMBOLA NA REGIÃO CENTRAL DO RIO GRANDE DO SUL, BRASIL / DISTRIBUTION AND DIVERSITY SPACE-TIME OF COLLEMBOLA CLASS IN CENTRAL REGION OF RIO GRANDE DO SUL, BRAZIL

Coghetto, Franciele 04 March 2015 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As long as the agricultural expansion progresses over the Pampa biome, the simplification and contamination of environments have become the main causing agents of loses of diversity of several soil organisms, among them the springtails. The Collembola class is one of the most plentiful groups present in the soil fauna; being responsible for the fragmentation of plant detritus, fungi dispersion, decomposition, nutrient mineralization and others; developing this way an elementary function at the dynamic of ecosystem operation. Springtails have a cosmopolitan distribution and can be found in almost all ecosystems, from the flooded areas until the higher elevations. Besides performing fundamental role at the ecosystem operation and be present in all zoogeographic regions, studies about Collembola class are overlooked and incipient at many areas, which is the case of Rio Grande do Sul. To that end, this study had as objective to schedule the distribution of springtails in different soil uses at the Central Depression Area of Rio Grande do Sul, allying taxonomic study to ecological parameters, aiming to contribute for the knowledge about dynamics of Collembola population in different soil uses at this region. Collects were performed with the aid of PROVID traps between November of 2013 and June of 2014, covering the annual seasonality. At all, were identified nineteen species and eighteen genders belonging to seven different families. The results showed indications of seasonality on the springtails distribution, and a preference for protected forest area, with eleven species belonging to six families collected. The area with less richness of species was the impacted one, with seven species belonging to four families, and the tillage with eight species belonging to four families collected. These data suggest to the loses of diversity caused, mainly, by ecosystem fragmentation and indiscriminate use of agrochemicals. / A medida que a expansão agrícola avança sobre os ecótopos do Bioma Pampa, a simplificação e a contaminação de ambientes tem se tornado os principais agentes causadores da perda de diversidade de vários organismos do solo entre eles os colêmbolos. A Classe Collembola é um dos grupos mais abundantes na fauna do solo, sendo responsável pela fragmentação de detritos vegetais, dispersão de fungos, decomposição, mineralização de nutrientes, entre outros, desempenhando assim papel fundamental na dinâmica do funcionamento dos ecossistemas. Os colêmbolos possuem distribuição cosmopolita e estão presentes em quase todos os ecossistemas, desde áreas alagadas até altitudes mais altas. Apesar de desempenhar papel fundamental no funcionamento dos ecossistemas e estarem presentes em todas as regiões zoogeográficas, estudos da Classe Collembola, são negligenciados e incipientes em várias regiões, como é o caso do Rio Grande do Sul. Neste intuito, o presente estudo teve como objetivo inventariar a distribuição dos colêmbolos em diferentes usos de solos na Depressão Central do Rio Grande do Sul, aliando o estudo taxonômico à parâmetros ecológicos, com fins de contribuir para o conhecimento da dinâmica populacional da Classe Collembola em diferentes usos de solo nesta região. Foram realizadas coletas com auxílio de armadilhas do tipo PROVID no período de novembro de 2013 à junho de 2014, de modo a cobrir a sazonalidade anual. Ao todo foram identificadas dezenove espécies, dezoito gêneros, pertencentes a sete famílias. Os resultados demostraram indícios de sazonalidade na distribuição dos colêmbolos e uma preferência pela área de floresta conservada, com onze espécies pertencentes a seis famílias, coletadas. Sendo que as áreas com menores riquezas de espécies foram a floresta impactada, com sete espécies pertencentes a quatro famílias e a lavoura com oito espécies, pertencentes a quatro famílias, coletadas. Esses dados sugerem para as perdas de diversidade causadas principalmente pela fragmentação de ecossistemas e pelo uso indiscriminado de agrotóxicos.
6

Diversidade morfológica de Collembola em sistemas de uso do solo no leste de Santa Catarina / Collembola morphological diversity in land-use systems in the Eastern region of Santa Catarina

Santos, Marcielli Aparecida Borges dos 23 February 2017 (has links)
Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-03-08T14:49:04Z No. of bitstreams: 1 PGCS17MA163.pdf: 2398294 bytes, checksum: 7b3bc412b8dffb1fe76e721e42fd8595 (MD5) / Made available in DSpace on 2018-03-08T14:49:04Z (GMT). No. of bitstreams: 1 PGCS17MA163.pdf: 2398294 bytes, checksum: 7b3bc412b8dffb1fe76e721e42fd8595 (MD5) Previous issue date: 2017-02-23 / Capes / The springtails (Collembola) are edaphic organisms with enormous morphological diversity and are affected by physical, chemical and biological soil properties. The aim of this study was to evaluate if the land-use influences the morphological diversity of springtails and to relate with the occurrence of these physical, chemical and microbiological soil attributes. Samples were collected in the eastern region of Santa Catarina, Brazil, involving three municipalities: Joinville, Blumenau and Timbó in the land-use systems (LUS) of native forest (NF), Eucalyptus plantation (EP), pasture (PA), integrated crop-livestock (ICL) and no-tillage crops (NT). The soil samples for determination of the edaphic attributes and the installation of Pitfall traps were carried in winter and summer, in the same points, from a sample grid of 3×3 points. The springtails captured were counted and morphotyped, observing characteristics such as: presence or absence of ocelli and fur, pigmentation, antenna length and furcula. For each one of these characteristics a score was assigned and by summing these values the morphotype and its adaptation to the soil were defined. The data were analyzed using abundance, Shannon-Wiener diversity index (H'), Pielou uniformity index (J), morphotypes richness and Margalef index, and modified Soil Biological Quality Index (QBS). Abundance was submitted to principal component analysis (PCA) to verify the relationship between morphotypes and LUS, using edaphic attributes as explicative environmental variables. The richness of springtails morphotypes was higher in NF and ICL, while the abundance was higher in ICL and PA in winter. The H' e Margalef indexes were higher in winter in the LUS where the intensity of use is lower (NF). In the summer, only H' differed significantly between LUS and was higher in NF. In all systems, the QBS index was higher in the summer season, with the exception of PA. The PCA showed a distinction between the seasons and the LUS, in which the occurrence of morphotypes was more related to microbiological attributes in the winter: microbial biomass carbon, microbial respiration and metabolic quotient; and chemical: potential acidity, organic matter and magnesium/potassium ratio. While in the summer, the morphotypes were explained by physical attributes: total porosity, biopores, soil moisture and macroporosity; and soil chemistry: organic matter and carbon/nitrogen ratio. The morphological diversity of springtails was influenced by conditions found in each LUS, showing sensitivity to changes in land-use, and thus can be considered a good tool for evaluation the biological quality of soil / Os colêmbolos (Collembola) são organismos edáficos com enorme diversidade morfológica e são influenciados pelas propriedades físicas, químicas e biológicas do solo. O objetivo deste estudo foi avaliar se o uso do solo influencia na diversidade morfológica de colêmbolos e relacionar a ocorrência destes com atributos físicos, químicos e microbiológicos do solo. Foram coletadas amostras na região do Leste Catarinense, envolvendo três municípios: Joinville, Blumenau e Timbó nos sistemas de usos do solo (SUS) de floresta nativa (FN), reflorestamento de eucalipto (RE), pastagem perene (PA), integração lavoura-pecuária (ILP) e plantio direto (PD). As coletas de solo para determinação dos atributos edáficos e a instalação de armadilhas de solo (Pitfall traps) foram realizadas no inverno e verão, nos mesmos pontos, em grade amostral de 3×3 pontos. Os colêmbolos capturados foram contados e morfotipados, observando características como: presença ou ausência de ocelos e pelos, pigmentação, comprimento de antenas e tamanho de fúrcula. Para cada uma destas características se atribuiu uma pontuação e por meio da soma desses valores definiu-se o morfotipo e a sua adaptação ao solo. Os dados foram analisados por meio da abundância, diversidade de Shannon-Wiener (H’), uniformidade de Pielou (J), riqueza de morfotipos e de Margalef, e Índice de Qualidade Biológica do Solo (QBS) modificado. A abundância foi submetida à análise de componentes principais (ACP) para verificar a relação entre os morfotipos e os SUS, usando os atributos edáficos como variáveis ambientais explicativas. A riqueza de morfotipos de colêmbolos foi mais elevada em FN e ILP, enquanto a abundância de colêmbolos foi maior em ILP e PA, no inverno. Os índices H’ e Margalef foram maiores no inverno no SUS em que a intensidade de uso é menor (FN). No verão, somente H’ diferiu significativamente entre os SUS e foi maior em FN. Em todos os SUS estudados o índice QBS foi mais elevado na época do verão, com exceção da PA. A ACP mostrou distinção entre as épocas e os SUS. No inverno a ocorrência de morfotipos esteve mais relacionada aos atributos microbiológicos: carbono da biomassa microbiana, respiração microbiana e quociente metabólico; e químicos: acidez potencial, matéria orgânica e relação magnésio/potássio. Enquanto no verão, a ocorrência dos morfotipos foi mais explicada pelos atributos físicos: porosidade total, bioporos, umidade e macroporosidade; e químicos do solo: matéria orgânica e relação carbono/nitrogênio. A diversidade morfológica de colêmbolos foi influenciada pelas condições encontradas em cada SUS, mostrando sensibilidade às alterações no uso do solo, e desta forma, pode ser considerada uma boa ferramenta para avaliação da qualidade biológica do solo
7

Varia??o temporal e descri??o de novas esp?cies de collembola (arthropoda, hexapoda) em uma ?rea de caatinga do nordeste do Brasil

Ferreira, Aila Soares 25 March 2013 (has links)
Made available in DSpace on 2014-12-17T15:37:17Z (GMT). No. of bitstreams: 1 AilaSF_DISSERT.pdf: 2602874 bytes, checksum: 17786cedd4c6cf455a1bade82e0156e9 (MD5) Previous issue date: 2013-03-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Collembola is one of the most abundant and diverse group of terrestrial arthropods, being at the base of the food chain operating in the decomposition process. They have a wide distribution in the world and can be found in practically all habitats. The knowledge of this distinctive fauna is still deficient in brazilian territory, especially in semi-arid region. The aim of this study was to investigate which climatic variables may act as predictors of species richness, abundance of individuals and compositional structure of the taxocenose of Collembola over 12 months in an area dominated by semi-arid Caatinga vegetation, northeastern Brazil and describe new species of the genus Seira found, more diverse taxon of Collembola in Brazil. Samples were collected in Jo?o C?mara, Rio Grande do Norte. Ten plots of 20 x 20 meters were established and the specimens were collected with collection effort of one hour/people using entomological aspirator. The identification and description of the species was carried out by studying the morphology and chaetotaxy. Was performed a multiple regression analysis between species richness and abundance of individuals with climatic variables. A total of 1231 individuals belonging to 15 species, 12 genera and nine families. The greatest richness and abundance of Collembola were found during the rainy season. The genus Seira was the most abundant. Rainfall explained the temporal variation in species richness and abundance of Collembola in the semi-arid region, which is consistent with the biology of these animals. The populations of Collembola showed grouped distribution. Three new species of Seira were described and illustrated and all show similarities with species already registered in the national territory / Collembola constitui um dos grupos mais abundantes e diversos de artr?podes terrestres, estando na base da cadeia alimentar e atuando no processo de decomposi??o. Possuem ampla distribui??o no mundo e podem ser encontrados em praticamente todos os habitats. O conhecimento desta distinta fauna ainda ? deficiente em territ?rio brasileiro, especialmente no semi?rido. O objetivo desse estudo foi investigar quais as vari?veis clim?ticas podem atuar como preditoras da riqueza de esp?cies, abund?ncia de indiv?duos e da estrutura composicional da taxocenose de Collembola ao longo de 12 meses em uma ?rea semi?rido dominada por vegeta??o de Caatinga, Nordeste brasileiro; e descrever novas esp?cies encontradas do g?nero Seira, t?xon mais diverso de Collembola no Brasil. As coletas foram realizadas em Jo?o C?mara, Rio Grande do Norte. Dez parcelas de 20 x 20 metros foram estabelecidas e os esp?cimes foram coletados com esfor?o de coleta de uma hora por pessoa utilizando um aspirador entomol?gico. A identifica??o e descri??o das esp?cies foram realizadas atrav?s do estudo da morfologia e quetotaxia dos exemplares. Foi realizada uma an?lise de regress?o m?ltipla entre a riqueza de esp?cies e a abund?ncia de indiv?duos com as vari?veis clim?ticas. Foi coletado um total de 1231 indiv?duos, distribu?dos em 15 esp?cies, 12 g?neros e nove fam?lias. As maiores riqueza e abund?ncia de Collembola foram encontradas durante a esta??o chuvosa. O g?nero Seira foi o mais abundante. A precipita??o explicou varia??o temporal da riqueza de esp?cies e abund?ncia de Collembola no semi?rido, o que condiz com a biologia desses animais. As popula??es de Collembola apresentaram distribui??o agrupada. Tr?s esp?cies novas de Seira foram descritas e ilustradas e todas apresentam semelhan?as com esp?cies j? registradas em territ?rio nacional
8

Teores de elementos potencialmente tóxicos em solos de uma bacia hidrográfica e avaliação de risco à saúde humana / Watershed soils contents of potentially toxics elements in soils from an watershed and human health risk assessment

Silva, Evandro Barbosa da 23 April 2013 (has links)
A contaminação dos solos por elementos potencialmente tóxicos (EPTs) provoca alterações na estrutura e no funcionamento dos ecossistemas, além de oferecer riscos à saúde pública. Os EPTs estão presentes naturalmente no ambiente, sendo constituintes de rochas e sedimentos. Entretanto, atividades antropogênicas como emissões industriais, uso de efluentes urbanos, dejetos de animais, biossólidos, fertilizantes e defensivos agrícolas podem contribuir para aumento da concentração dos EPTs. O solo é um dos principais meios de exposição dos EPTs aos seres humanos. Logo, é importante quantificar os teores dos EPTs nos solos e sua distribuição na microbacia para poder avaliar o risco a saúde humana. Os efeitos dos elementos tóxicos que chegam ao solo sobre a diversidade e funcionalidade da biota podem ser avaliados por meio de testes ecotoxicológicos. Alguns organismos são bons indicadores ambientais por participarem de processos biológicos importantes do solo. Os principais organismos utilizados são os colêmbolos, artrópodes terrestres com alta diversidade e abundância, sendo encontrado em todos os biomas. Nesse estudo, quantificaram-se os teores de Arsênio (As), Cádmio (Cd), Cobalto (Co), Cobre (Cu), Cromo (Cr), Chumbo (Pb), Níquel (Ni) e Zinco (Zn) em amostras de 15 solos da microbacia do Rio Guamium, localizada em Piracicaba, São Paulo. Foi realizado experimento em casa de vegetação com alface (Lactuca sativa L.), pepino (Cucumis sativus L.), beterraba (Beta vulgaris L.) e rúcula (Eruca sativus Mill.) para avaliar o risco a saúde humana. Foi avaliado também o efeito da aplicação de doses de As na reprodução dos colêmbolos. Para tanto, foram coletadas amostras de solos nas profundidades 0 - 0,1; 0,1 - 0,2; 0,2 - 0,3; 0,3 - 0,4; 0,4 - 0,6; 0,6 - 0,9 e 0,9 - 1,2 m. Foi realizada a extração dos EPTs pelo método EPA 3051a (0,5 g de solo + 9 ml HNO3 + 3 ml HCl com digestão assistida por forno microondas). Os EPTs que apresentaram as maiores concentrações foram o As (3 pontos) e Cu (1 ponto), sendo as concentrações superiores ou iguais ao valor de prevenção estabelecido pelo órgão ambiental paulista (Cetesb). O As apresentou elevado risco carcinogênico, enquanto o Cu apresentou risco à saúde humana apenas quando 100 % dos vegetais consumidos eram provenientes da área com elevado teor de Cu, sendo este o cenário mais restritivo. Houve diferença na disponibilidade de As entre o solo natural e o solo artificial tropical (SAT), composto por areia, caulinita e pó de fibra de coco. O SAT apresentou alta disponibilidade de As o que reduziu a taxa de reprodução dos colêmbolos. No SAT a LOEC (Lowest Observed Effect Concentration) foi 0,25 mg kg-1 e a NOEC (No Observed Effect Concentration) < 0,25 mg kg-1. No solo natural não foi possível determinar a NOEC, enquanto a LOEC foi 8,41 mg kg-1. / Soil contamination by potential toxics elements (PTEs) can change the ecosystem structure, its function and can cause risk to human health. PTEs occur naturally in the environment; however human activities such as industrial emissions, urban sewage, animal waste, biosolids, fertilizers and pesticides can increase their concentration. Soil is one of the main pathways to human exposure, so it is important to evaluate the contents of PTEs in soils and their distribution in the watershed in order to assess the human health risk. The effects of PTEs that reach the soil on the diversity and functionality of microorganisms can be evaluated by ecotoxicological tests. Organisms that take part of the biological process can be used as environment quality indicators. One of them is the springtails (Collembola) that are wide spread and have high diversity, being found in all ecosystems. In this study, we evaluated the Arsenic (As), Cadmium (Cd), Cobalt (Co), Copper (Cu), Chromium (Cr), Lead (Pb), Nickel (Ni) and Zinc (Zn) contents in 15 soil from Guamium watershed, located in Piracicaba, state of Sao Paulo, Brazil. To assess the human health risk lettuce (Lactuca sativa L.), cucumber (Cucumis sativus L.), sugar beet (Beta vulgaris L.) and rocket (Eruca sativus Mill.) were cultivated under greenhouse conditions. The effect of As rates on collembola reproduction was also evaluated. Soil samples were collected in the following depths: 0 - 0.1; 0.1 - 0.2; 0.2 - 0.3; 0.3 - 0.4; 0.4 - 0.6; 0.6 - 0.9 e 0.9 - 1.2 m. Contents of PTEs were obtained after microwave extraction by EPA 3051a method (0.5 g soil + 9 mL HNO3 + 3 mL HCl). As and Cu had the highest contents, and their concentration were close or higher than prevention value established by Sao Paulo state environmental agency (Cetesb). As showed high carcinogenic risk, otherwise Cu only represented risk to human health in the most restrictive scenario, when 100% of the vegetables consumed were taken from the contaminated area. There was difference in the As availability between natural soil and artificial soil (ArtS) which was composed by sand, Kaolinite and powdered coconut fiber. As availability was high in the ArtS and it decreased the collembola reproduction. The Lowest Observed Effect Concentration (LOEC) on SAT were 0.25 mg kg-1, while and the No Observed Effect Concentration (LOEC) were less than 0.25 mg kg-1. Otherwise, the LOEC were 8.41 mg kg-1 in the natural soil, but it was not possible to define the NOEC.
9

Teores de elementos potencialmente tóxicos em solos de uma bacia hidrográfica e avaliação de risco à saúde humana / Watershed soils contents of potentially toxics elements in soils from an watershed and human health risk assessment

Evandro Barbosa da Silva 23 April 2013 (has links)
A contaminação dos solos por elementos potencialmente tóxicos (EPTs) provoca alterações na estrutura e no funcionamento dos ecossistemas, além de oferecer riscos à saúde pública. Os EPTs estão presentes naturalmente no ambiente, sendo constituintes de rochas e sedimentos. Entretanto, atividades antropogênicas como emissões industriais, uso de efluentes urbanos, dejetos de animais, biossólidos, fertilizantes e defensivos agrícolas podem contribuir para aumento da concentração dos EPTs. O solo é um dos principais meios de exposição dos EPTs aos seres humanos. Logo, é importante quantificar os teores dos EPTs nos solos e sua distribuição na microbacia para poder avaliar o risco a saúde humana. Os efeitos dos elementos tóxicos que chegam ao solo sobre a diversidade e funcionalidade da biota podem ser avaliados por meio de testes ecotoxicológicos. Alguns organismos são bons indicadores ambientais por participarem de processos biológicos importantes do solo. Os principais organismos utilizados são os colêmbolos, artrópodes terrestres com alta diversidade e abundância, sendo encontrado em todos os biomas. Nesse estudo, quantificaram-se os teores de Arsênio (As), Cádmio (Cd), Cobalto (Co), Cobre (Cu), Cromo (Cr), Chumbo (Pb), Níquel (Ni) e Zinco (Zn) em amostras de 15 solos da microbacia do Rio Guamium, localizada em Piracicaba, São Paulo. Foi realizado experimento em casa de vegetação com alface (Lactuca sativa L.), pepino (Cucumis sativus L.), beterraba (Beta vulgaris L.) e rúcula (Eruca sativus Mill.) para avaliar o risco a saúde humana. Foi avaliado também o efeito da aplicação de doses de As na reprodução dos colêmbolos. Para tanto, foram coletadas amostras de solos nas profundidades 0 - 0,1; 0,1 - 0,2; 0,2 - 0,3; 0,3 - 0,4; 0,4 - 0,6; 0,6 - 0,9 e 0,9 - 1,2 m. Foi realizada a extração dos EPTs pelo método EPA 3051a (0,5 g de solo + 9 ml HNO3 + 3 ml HCl com digestão assistida por forno microondas). Os EPTs que apresentaram as maiores concentrações foram o As (3 pontos) e Cu (1 ponto), sendo as concentrações superiores ou iguais ao valor de prevenção estabelecido pelo órgão ambiental paulista (Cetesb). O As apresentou elevado risco carcinogênico, enquanto o Cu apresentou risco à saúde humana apenas quando 100 % dos vegetais consumidos eram provenientes da área com elevado teor de Cu, sendo este o cenário mais restritivo. Houve diferença na disponibilidade de As entre o solo natural e o solo artificial tropical (SAT), composto por areia, caulinita e pó de fibra de coco. O SAT apresentou alta disponibilidade de As o que reduziu a taxa de reprodução dos colêmbolos. No SAT a LOEC (Lowest Observed Effect Concentration) foi 0,25 mg kg-1 e a NOEC (No Observed Effect Concentration) < 0,25 mg kg-1. No solo natural não foi possível determinar a NOEC, enquanto a LOEC foi 8,41 mg kg-1. / Soil contamination by potential toxics elements (PTEs) can change the ecosystem structure, its function and can cause risk to human health. PTEs occur naturally in the environment; however human activities such as industrial emissions, urban sewage, animal waste, biosolids, fertilizers and pesticides can increase their concentration. Soil is one of the main pathways to human exposure, so it is important to evaluate the contents of PTEs in soils and their distribution in the watershed in order to assess the human health risk. The effects of PTEs that reach the soil on the diversity and functionality of microorganisms can be evaluated by ecotoxicological tests. Organisms that take part of the biological process can be used as environment quality indicators. One of them is the springtails (Collembola) that are wide spread and have high diversity, being found in all ecosystems. In this study, we evaluated the Arsenic (As), Cadmium (Cd), Cobalt (Co), Copper (Cu), Chromium (Cr), Lead (Pb), Nickel (Ni) and Zinc (Zn) contents in 15 soil from Guamium watershed, located in Piracicaba, state of Sao Paulo, Brazil. To assess the human health risk lettuce (Lactuca sativa L.), cucumber (Cucumis sativus L.), sugar beet (Beta vulgaris L.) and rocket (Eruca sativus Mill.) were cultivated under greenhouse conditions. The effect of As rates on collembola reproduction was also evaluated. Soil samples were collected in the following depths: 0 - 0.1; 0.1 - 0.2; 0.2 - 0.3; 0.3 - 0.4; 0.4 - 0.6; 0.6 - 0.9 e 0.9 - 1.2 m. Contents of PTEs were obtained after microwave extraction by EPA 3051a method (0.5 g soil + 9 mL HNO3 + 3 mL HCl). As and Cu had the highest contents, and their concentration were close or higher than prevention value established by Sao Paulo state environmental agency (Cetesb). As showed high carcinogenic risk, otherwise Cu only represented risk to human health in the most restrictive scenario, when 100% of the vegetables consumed were taken from the contaminated area. There was difference in the As availability between natural soil and artificial soil (ArtS) which was composed by sand, Kaolinite and powdered coconut fiber. As availability was high in the ArtS and it decreased the collembola reproduction. The Lowest Observed Effect Concentration (LOEC) on SAT were 0.25 mg kg-1, while and the No Observed Effect Concentration (LOEC) were less than 0.25 mg kg-1. Otherwise, the LOEC were 8.41 mg kg-1 in the natural soil, but it was not possible to define the NOEC.
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Sylviculture intensive en région boréale : impact de la mixité des essences sur le processus de décomposition des litières et le stockage de carbone / Intensive silvicultural system in the boreal region : impact of mixing tree species on litter decomposition process and carbon storage

Chomel, Mathilde 24 November 2014 (has links)
Depuis quelques années la sylviculture intensive prend une grande ampleur afin de rapprocher la source de fibres des usines, d'accroître la productivité des plantations, et de diminuer la pression de coupe sur les forêts naturelles. Toutefois un débat sur le type d'aménagement optimal des plantations oppose l'aménagement mono- et pluri-spécifique. Il est important de mieux comprendre le fonctionnement de ces écosystèmes pour en effectuer une bonne gestion et d'optimiser les services écosystémiques que ces plantations fournissent. La décomposition des litières et le recyclage des nutriments sont des processus complexes essentiels au fonctionnement des écosystèmes. Ainsi mon projet de thèse visait à mieux comprendre l'influence de la mixité de deux essences forestières, à savoir l'épinette blanche et le peuplier hybride, en comparaison à des plantations pures sur le processus de décomposition des litières et le stockage de carbone. Les résultats de cette étude ne montrent pas d'amélioration du processus de décomposition avec le mélange du peuplier et de l'épinette ou de leurs litières. En revanche, le mélange de ces deux espèces en plantation tamponne les effets contrastés du peuplier et de l'épinette observés dans les plantations monospécifiques. De plus, le stockage de carbone et la productivité du peuplier sont améliorés dans les plantations mixtes par rapport aux plantations monospécifiques. Les herbacées semblent être bénéfiques pour la diversité d'organismes et favorisent la libération d'azote des litières d'arbres. Cet aspect pourrait contrebalancer l'effet négatif de la présence d'herbacées qui entrent en compétition avec les arbres pour les ressources. / The use of trees under intensive management is particularly important for rapid fibre production and for reduce cutting pressure on natural forests in boreal regions. However, a debate on the best type of plantation management opposes the mono-and pluri-specific management. Despite the possible antagonistic effects on productivity, it seems that mixed plantations would have benefits on soil properties, environmental stability, but also to maintain biodiversity and aesthetic value. It is important to better understand the functioning of these ecosystems to make good management in order to optimize ecosystem services of these plantations. Litter decomposition and nutrient cycling are essential process for the ecosystems functioning. My thesis project was to better understand the influence of the mixing of two tree species planted in comparison to monospecific plantations, namely white spruce and hybrid poplar, on the litter decomposition process and carbon storage. The results of this study showed no improvement in the decomposition process with the mixture of poplar and spruce in plantation or by their litters mixture. However, the mixture of the two species in plantation buffers the contrasting effects of poplar and spruce observed in monospecific plantations. In addition, carbon storage and productivity of poplars are improved in mixed plantations compared to monospecific plantations. Herbaceous litter appears to be beneficial for the abundance of organisms and promote the release of nitrogen from tree litter. This could offset the negative effect of the presence of grasses that compete with trees for resources.

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