In an era when cities and towns are changing rapidly, public spaces are the key to reviving civic engagement. By re-introducing these public realms as ecological environments, we can re-structure the organic growth of civic tissue, re-define the city street into a park environment, and reveal the ecological landmarks that once beautified the landscape. These ecological landmarks will be used as corridors, nodes of circulation and storm water management to not only creates a regenerative landscape but to create a connection between ecology, suburbia and the city. The public realm in America has two roles: it is the dwelling place of our civilization and our city life, and our physical manifestation of the common good. When we degrade the public realm, we will automatically degrade the quality of our city and our city life, plus the character of all the enactments of our public life and communal life that takes place there. The public realm has to inform us not only where we are geographically, but has to inform us where we are in our culture, where we've come from, what kind of people we are, and it needs to afford us a glimpse as to where we are going. The past sixty years has engendered a decentralization of the city and a loss of our public realm. Suburbia was created and the absence of community development within cities increased. The lack of social economic interaction now challenges each city today. The inabilities to obtain a socially sustainable closed-loop system lifestyle are some of the challenges families continually battle. Transformation, succession and operation will help to emphasize and revitalize the downtown riverfront district in Nashville, Tennessee and create a living, dynamic entity that connects you to suburbia and an ecological dwelling environment. A naturalized mouth and iconic identity to the river will create a comprehensive plan for addressing urban design and the connection between the two sides of the river. Transportation, naturalization, sustainability and other ecological issues will be addressed in the development of a sustainable "green city," a new destination where city, river and suburbia interact in a dynamic and balanced relationship creating an urban estuary.

Extensive research conducted over the last decade has demonstrated the great potential of phytostabilization for the reclamation of abandoned mine tailing piles. The right combination of plant species and soil amendments can facilitate the growth of a permanent vegetative cover on the tailings that will help minimize the mobilization of metal-bearing particles by means of wind dispersion and water erosion. Despite previous research efforts, the diversity and potential role of microbial populations inhabiting the root zone of the plants on the stabilization of the metal(loid) contaminants remains mostly unresolved. The study presented in this dissertation represents one of the first comprehensive efforts aimed to understand the ecology and dynamics of microbial communities colonizing both bulk and rhizosphere tailings during phytostabilization as an initial step towards elucidating the role of microbes in the stabilization of metal(loid) contaminants during the remediation treatment. This study was divided into two main projects: (1) the first aimed to monitor the temporal variations in functional and taxonomic diversity of prokaryotic populations in acid-generating metalliferous mine tailings during phytostabilization to determine how they respond to and/or influence changes in environmental parameters and to identify key patterns in their composition that may serve as bioindicators of soil health and the success of the remediation treatment; and (2) the second aimed to expand our understanding of the dynamics of root-associated bacterial, fungal and archaeal communities during mine tailing phytostabilization and how the dynamic behavior of the communities correspond to the growth of plants, the addition of soil amendments, and fluctuations in environmental conditions. The results presented here demonstrate that different microbial groups respond differently to changes in environmental conditions during phytostabilization, suggesting that by monitoring the behavior of specific microbial groups in the systems (as bioindicators) we may be able to assess the effectiveness of the remediation treatment. Furthermore, the results from the taxonomic and functional analysis of the microbial communities served as the basis for the development of a model that explains the ecology and distribution of dominant microbial groups in the tailings that may significantly contribute to the oxidation of iron-sulfides, the production of acid mine drainage, and to facilitate plant establishment and survival during phytostabilization.

Phytostabilization is an emerging technology for the remediation of mine tailings sites. In arid and semiarid environments, mine tailings disposal sites are a major source of environmental pollution as they are subject to eolian dispersion and water erosion. Mine tailings are acidic to neutral, high in metal content, and nutrient poor. Furthermore, these sites remain unvegetated even after decades of no additional mining activity. In arid and semiarid regions, climatic variables such as high winds, salinity, and drought exacerbate the problem. The Klondyke mine tailings site is a model site for studying plant establishment in mine tailings within semiarid regions. It was a lead and zinc ore- processing operation from 1948 to 1958 and is similar in physicochemical characteristics to other acidic pyritic mine tailings.In a greenhouse study, a native drought tolerant halophyte, Atriplex lentiformis (Torr.) S. Wats., was evaluated for its potential as a phytostabilization candidate in compost-amended tailings from the Klondyke site. Germination, plant growth, and metal uptake of A. lentiformis were examined, and the microbial community was monitored by enumeration of autotrophic iron- and sulfur-oxidizing bacteria as well as heterotrophic bacteria. Results demonstrated that with 10 to 15% compost addition, growth of A. lentiformis was not affected and shoot metal concentrations were generally not a concern for foraging animals. Furthermore, the heterotrophic bacterial community is severely stressed but recovers with compost addition and successful plant growth. Therefore, A. lentiformis is a good candidate for phytostabilization of mine tailings with compost amendments.Poor revegetation of mine tailings has been attributed to the microbial community involved in acidifying tailings; however, no thorough microbial studies have been conducted. The second study characterizes the bacterial community of the Klondyke site and compares it to an offsite control sample. Results demonstrate that the heterotrophic community is indicative of soil health as it has a positive relationship with pH, phylotype richness, and diversity. Also, the mine tailings contain an unexplored diversity of acidophiles that are important in maintaining acidity and thus, metal bioavailability. Therefore, the bacterial community in mine tailings should be monitored in phytostabilization studies to evaluate restoration.

Toxic elements are present in polluted water from mines, industrial outlets, storm water etc. Wetland plants take up toxic elements and increase the pH of the medium. In this thesis was investigated how the shoots of submerged plants and roots of emergent plants affected the pH of the surrounding water in the presence of free toxic ions. The aim was to clarify the mechanisms by which these plants change the surrounding water pH in the presence of toxic ions. The influence of Elodea canadensis shoots on the pH of the surrounding water was studied in the presence of cadmium (Cd) at low initial pH (4-5). The involvement of photosynthetic activity in the pH changes was investigated in the presence and absence of Cd. The cytosolic, vacuolar and apoplasmic pH changes as well as cytosolic Cd changes in E. canadensis were monitored. The influence of Eriophorum angustifolium roots on the pH of the surrounding water was investigated in the presence of a combination of Cd, copper, lead, zinc and arsenic at low initial pH (3.5). Eriophorum angustifolium root exudates were analyzed for organic acids. Elodea canadensis shoots increased the pH of the surrounding water, an effect more pronounced with increasing Cd levels and/or increasing plant biomass and increased plant Cd uptake. The pH increase in the presence of free Cd ions was not due to photosynthesis or proton uptake across the plasmalemma or tonoplast. Cadmium was initially sequestered in the apoplasm of E. canadensis and caused its acidosis. Eriophorum angustifolium roots increased the surrounding water pH and this effect was enhanced in the presence of arsenic and metals. This pH increase was found to depend partly on the release of oxalic acid, formic acid and succinic acid by the plants. In conclusion, E. canadensis shoots and E. angustifolium roots were found to increase the low initial pH of the surrounding water. The pH modulation by these species was enhanced by low levels of free toxic ions in the surrounding water. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Submitted. Paper 4: Manuscript.

Made available in DSpace on 2015-03-26T13:36:42Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1139190 bytes, checksum: 7d7600e51fc96aab96c671593415f23b (MD5) Previous issue date: 2011-07-29 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Arsenic is the more dangerous element to human health. Phytoremediation is an important technology to reduce the antropogenic effect in the environmental contamination, but it is necessary a detailed knowledge of tolerance mechanism, which is the goal of this work. We choose Brassica juncea, tolerant plant to several heavy metals, such as cadmium, and a plant of rapid growth. The arsenate was added to nutritive solution at final concentrations of 10, 50, 200 and 500 μM, and data was collected after 6, 10, 13, 14, 15 and 16 days of exposition. Higher the arsenic in the treatment, higher the level found in leaves, stalk and in roots reach the highest level (5457 mg Kg-1). This amount was 26 and 34 times higher than that found in stalk and leaves, respectively. No alteration in phosphorus level was found at any treatment . This absence of phosphate uptake inhibition seems to have a contribution to the tolerance found in this genotype. In contrast, arsenic concentrations equal or higher than 50 μM were associated with increase in sulphur content in roots in parallel with an increase in total phenol content in these organs, while it reduced sulfur levels in leaves. The two highest doses of arsenate led to the appearance of toxicity symptoms in leaves, characterized by marginal chlorosis and purple coloring in the abaxial faces of old leaves. Despite the highest levels of arsenic in roots, no change in root length and dry weight was detected. In shoot however, we observed reduction in leaf area, leng th and fresh weight in plants treated with 200 and 500 mM arsenate. Additionally, only the highest dose has produced a reduction in net photosynthesis (A) and stomatal conductance (gS) by the 13th day. On the 14th day it was possible to observe the reduction of these parameters in plants treated with 200 mM arsenate. Longer periods in the presence of hight doses allowed us to observe that, besides the reduction in stomatal opening, arsenic could also produce biochemical limitation to photosynthesis, which was associated to reduction in electron transport rate (ETR) and in the quantic efficiency of photosystem II [Y(II)], concomitantly with increase in the level of energy loss as heat [Y(NPQ)]. The second higher dose (200 μM) has not altered the A and other fluorescence parameters, by the 13th day and only negligible effects in leaf area and dry mass in parallel to no effect in roots was observed. Altogether these data support that the genotype of Brassica juncea under study is tolerant to arsenic. Despite of accumulation of high levels of arsenic in roots, no oxidative damage was observed, and no effects in root growth was noted. The fact that high levels of arsenic has occurred in roots, with minor effects in growth indicate the great potential of this plant to be used in phytoremediation as a phytostabilizer. / O arsênio é considerado o elemento mais perigoso para a saúde humana. Fitorremediação é uma importante tecnologia para amenizar o efeito antropogênico na contaminação ambiental, mas para o seu sucesso é necessário a compreensão detalhada dos mecanismos de tolerância de metais pesados, objetivo deste trabalho. A espécie escolhida foi a Brassica juncea, tolerante a vários metais, como cádmio e zinco, e que possui um crescimento rápido. O arsênio foi fornecido a solução nutritiva na forma de arsenato de sódio nas concentrações de 10, 50, 200 e 500 μM, sendo coletados dados aos 6, 10, 13, 14, 15 e 16 dias após a exposição. Quanto maiores os níveis de arsênio presentes no tratamento, maiores os níveis encontrados na planta, havendo um acúmulo de até 5457 mg Kg-1 de As nas raízes expostas a 500 μM de arsenato. Esta quantidade foi 26 e 34 vezes superior aquela observada em caules e folhas, respectivamente. Em nenhum dos tratamentos foram observadas alterações na concentração de fósforo. Esta ausência de inibição de acúmulo de fósforo pode significar a presença de um mecanismo de tolerância à toxidez do arsênio neste genótipo. Em contraste, doses de arsênio iguais ou superiores a 50 μM aumentaram os níveis enxofre nas raízes, em paralelo com um aumento no teor de fenóis, ao passo que reduziu os níveis de enxofre na folha. As duas maiores doses de arsenato levaram ao aparecimento de sintomas de toxidez nas folhas, caracterizados por clorose marginal e coloração arroxeada nas faces abaxiais de folhas velhas. Apesar dos altos níveis de arsênio em raízes, não houve redução no comprimento e na massa seca deste órgão. Na parte aérea por outro lado, foi observada a redução na área foliar, comprimento e massa fresca em plantas tratadas com 200 e 500 μM de arsenato. Adicionalmente observou-se que somente a maior dose reduziu a fotossíntese líquida (A) e condutância estomática (gS) até o 13º dia. A partir do 14º dia já foi possível observar a queda destes parâmetros em plantas tratadas com 200 μM de arsenato. Maiores períodos na presença altas doses de arsenato permitiram observar que alem da redução da abertura estomática, há uma limitação bioquímica contribuindo para a redução da fotossíntese. A diminuição em A esteve associada a limitações na etapa fotoquímica onde ocorreu uma redução na taxa linear de transporte de elétrons (ETR) e na eficiência quântica do fotossistema II [Y(II)], concomitante com o aumento da perda da energia luminosa na forma de calor [Y(NPQ)]. A segunda maior dose (200 μM) não provocou redução em A e nos parâmetros fotoquímicos até o 13º dia, com reduções negligíveis na área e massa foliar, com nenhum efeito no crescimento das raízes. Em conjunto, estes resultados permitem evidenciar que o genótipo de Brassica juncea em estudo possui tolerância aos níveis de arsênio. Apesar de acumular níveis altíssimos de arsênio nas raízes, estas plantas não apresentaram dano oxidativo, nem redução na acumulação de massa seca nas raízes. O fato de que altos níveis de As seja acumulado nas raízes, com efeitos reduzidos no seu crescimento, indica o grande potencial desta espécie para o seu uso na fitorremediação como uma espécie fitoestabilizadora.

O avanço industrial e urbano associado ao aumento da produção dos bens de consumo resultou na geração de resíduos que, por muito tempo, foram descartados indiscriminadamente no ambiente, provocando danos quase sempre irreversíveis e de difícil recuperação. Dois experimentos foram conduzidos em solos contaminados por metais pesados, o primeiro devido ao descarte de produtos inorgânicos contendo grande carga de poluentes no solo; no segundo estudo a contaminação deve-se ao uso sucessivo de fungicidas contendo cobre em pomares cítricos do sul da Flórida. O primeiro estudo objetivou avaliar o uso de amenizantes orgânicos como mitigadores da toxicidade de bário, boro, cádmio, chumbo, cobre, níquel e zinco presentes no solo contaminado decorrente da adição de resíduo de sucata automobilística e avaliar o potencial fitoextrator do pinhão-manso (Jatropha curcas L.). Observou-se que o fornecimento da matéria orgânica na forma de turfas não amenizou a contaminação por metais pesados (Ba, Cd, Cu, Ni, Pb,Zn) e B; tal efeito pode ter ocorrido devido ao elevado pH deste solo mantido pelas práticas constantes de calagem. Os elementos apresentaram maior disponibilidade no solo ao longo das avaliações, exceto o boro que não apresentou significância. As plantas apresentaram sintomas de fitotoxicidade causados pelo elevado teor de boro e metais pesados no solo. A maior parte dos elementos metálicos se acumulou nos colmos e o boro nas folhas do pinhão manso, ou seja, a planta foi eficiente em translocar tais elementos para a parte aérea, situação desejável em uma fitoextratora. Ao final do experimento, os teores de Ba, Cd, Cu, Ni, Pb e Zn estavam mais disponíveis às plantas. O que indica que a matéria orgânica presente nas turfas mineralizou e tornou mais disponível estes metais pesados às plantas ao longo das avaliações. Pelos índices de transferência, de translocação e de remoção o pinhão manso foi viável somente para fitoextração de boro da área contaminada; estes índices também apontaram que o pinhão manso apresentou potencial para acumular B, Ba e Cd. O segundo experimento foi desenvolvido em casa de vegetacão com um argissolo coletado em uma área que tem recebido sucessivas aplicações de fungicidas a base de cobre, o que tem promovido o acúmulo significativo deste elemento nos solos sob produção de citros. O objetivo foi avaliar o potencial de fitoextração de cobre pelas plantas chinesas Splendens elsholtzia e Argyi elsholtzia para remover o excesso de cobre em solos contaminados devido a aplicação sucessiva de fungicidas cúpricos em pomares cítricos do sul da Flórida. A produção de massa seca de folhas, colmos e raízes e a concentração de cobre nos tecidos da Splendens elsholtzia foram superiores ao da espécie Argyi elsholtzia, o que indica que a Splendens elsholtzia é mais tolerante aos elevados níveis de cobre no solo. Assim, esta espécie pode ser indicada para programas de fitoextração em solos contaminados com cobre; entretanto, o índice de translocação do cobre indicou que as duas espécies não foram eficientes em translocar o cobre da raíz para parte aérea. / The industrial and urban progress associated with increased production of consumer goods has resulted in the generation of waste, which, for a long time, was indiscriminately discarded in the environment, causing damage usually irreversible to recover. Two experiments were conducted in soils contaminated with heavy metals: the first aimed at the disposal of products containing high loads of inorganic pollutants in the soil and the second focused on contamination due to the successive uses of fungicides containing copper in citrus groves of South Florida. The first study aimed to evaluate the use of organic soothers as mitigators of toxicity caused by barium, boron, cadmium, lead, copper, nickel and zinc in soil contaminated with waste resulting from the disposal of automobile scrap and to evaluate the phytoextraction potential of Jatropha (Jatropha curcas L.). It was observed that the supply of organic matter in the form of peat did not alleviate the contamination with heavy metals (Ba, Cd, Cu, Ni, Pb, Zn) and B, which may be attributed to the high pH of the soil due to constant practices of liming. The items showed higher availability in the soil during the evaluations, except for boron which showed no significance. The plants showed symptoms of phytotoxicity caused by high levels of boron and heavy metals in the soil. Most metallic elements are accumulated in the stems and boron in the leaves of Jatropha curcas, thus, the plant was efficient in the translocation of these elements to the shoot, a situation is desirable in phytoextraction. At the end of the experiment, the concentrations of Ba, Cd, Cu, Ni, Pb and Zn were more available to plants. This indicates that the organic matter present in the peat mineralized and made these heavy metals more available to plants. Considering the transfer rates of translocation and removal, the Jatropha was feasible only for phytoextraction of boron in the contaminated area, which shows that Jatropha has the potential to accumulate B, Ba and Cd. The second experiment was conducted in a greenhouse in an alfisol collected in an area that received repeated applications of copper-based fungicides, which promoted significant accumulation of this element in soils under citrus production. The objective was to evaluate the potential for phytoextraction of copper by the Chinese plants Splendens elsholtzia and Argyi elsholtzia to remove excess of copper in contaminated soils due to repeated application of copper-based fungicides in citrus groves of South Florida. The dry weight of leaves, stems and roots and the concentration of copper in the tissues of Splendens elsholtzia were higher than in Argyi elsholtzia, which indicates that the Splendens elsholtzia is more tolerant to high copper levels in the soil. Thus, this species may be indicated for phytoextraction of soils contaminated with copper; however, the rate of copper translocation indicated that the two species were not efficient to translocate copper from root to shoot.

Le phytomanagement est un mode de gestion de sites et sols pollués émergent qui inclut la valorisation de la biomasse produite. Pour alimenter les retours d’expérience en conditions réelles et sur le long terme, deux essais de phytomanagement de 1 ha chacun (sites A et B) ont été mis en place à Fresnes-sur-Escaut (Hauts-de-France) en 2011/2012 sur un terrain de gestion de sédiments de curage contaminés par des éléments potentiellement toxiques ou EPT (Cd, Cu, Pb et Zn). Dans ce contexte, les travaux de thèse réalisés sur ces sites avaient pour objectifs d’étudier : (1) la dynamique et la performance des espèces végétales sélectionnées (Deschampsia cespitosa, peupliers Skado et I-214, saule Tordis et Inger), des plantes colonisatrices et envahissantes, (2) l’effet des amendements (inoculum de champignons mycorhiziens, amendement minéral basique) sur la mobilité des EPT dans le sol, sur l’accumulation des EPT dans les parties aériennes des plantes et impact sur la diversité microbienne des sols et des racines ligneuses.L’efficacité de l’espèce herbacée D. cespitosa pour le phytomanagement du site B a été démontrée. Tolérante aux conditions du site, cette plante a présenté de faibles concentrations en Cd, Cu et Pb dans ses parties aériennes et a formé un couvert dense et pérenne. La végétalisation du site A par des plantes colonisatrices était hétérogène avec une dominance de l’espèce Urtica dioïca.Sur les parcelles amendées et non amendées, les concentrations mesurées chez U. dioïca étaient plus élevées en Cd, Pb, Cu et Zn comparées aux mêmes plantes issues de sols non contaminés. Selon les calculs préliminaires de risques basés sur les concentrations mesurées dans les plantes herbacées enrichies en Cd et Zn, les risques liés à leur ingestion par les herbivores se sont avérés négligeables.Concernant les saules et les peupliers dédiés à la production d’énergie, de fortes concentrations en Cd et en Zn ont été mesurées dans les feuilles quels que soient les amendements. Ces feuilles peuvent représenter un risque pour les herbivores. Contrairement aux peupliers très tolérants aux conditions du milieu, une réduction de la croissance et du taux de survie des saules a été mesurée sur les parcelles amendées et non amendées en présence de D. cespitosa, liée à une forte compétition souterraine avec D. cespitosa. L’utilisation de tests écotoxicologiques a permis d’identifier d’autres facteurs dont la phytotoxicité du sol. Par ailleurs, aucun effet des amendements biologiques et chimiques n’a été observé sur la mobilité et la spéciation des EPT après 4 ou 5 années de phytomanagement. Leur effet sur le transfert des EPT était très variable en fonction des espèces, des niveaux de pollution et du temps. L’étude des communautés microbiennes dans les racines ligneuses a révélé un impact de la végétation herbacée et de la pollution mais aucun effet lié aux amendements n’a été observé. / Phytomanagement is an emerging approach that includes plant biomass valorization for the management of polluted soils and sites. To evaluate the long-term performance of this strategy at field scale, two phytomanaged sites of 1 ha each (sites A and B) were implanted in Fresnes-sur-Escaut (Hauts-de-France) in 2011/2012 at a dredged-sediment disposal site contaminated with potentially toxic elements or PTE (Cd, Cu, Pb et Zn). The thesis work is based on the study of the two sites with the following objectives: (1) study the dynamics of selected plants (Deschampsia cespitosa, Skado and I-214 poplars, Tordis and Inger willows), colonizing plants and invaders, (2) study the efficiency of amendments (mycorrhizal fungi inoculum, basic mineral amendment) on sediment PTE mobility, on aerial plant parts PTE accumulation and on the microbial diversity in soils and tree roots.The efficiency of the grass D. cespitosa for phytomanagement at the site B has been highlighted. The plant was tolerant to the site conditions, had low concentrations of Cd, Cu and Pb in shoots and formed a dense and perennial plant cover. At the site A, the herbaceous plant cover formed by plant colonists was heterogenous with a dominance of the species Urtica dioïca.In amended and non-amended plots, U. dioïca showed higher concentrations of Cd, Cu, Pb and Zn than the same plants from uncontaminated soils. According to risk calculations based on Cd and Zn concentrations, there was no risk related to the ingestion of these herbaceous plants by herbivorous animals. Concerning poplars and willows dedicated to energy production, high Cd and Zn concentrations were found in their leaves regardless of the amendments. These leaves may pose a risk for herbivorous animals. Unlike poplars which were very tolerant to the site conditions, willows showed a reduction of growth and survival rate in the amended and non-amended plots sown with D. cespitosa, because of belowground competition with D. cespitosa. Ecotoxicological tests revealed that soil phytotoxicity was also responsible of the willow growth reduction. Besides, the biological and chemical amendments had no significant effect on PTE mobility and speciation in soils after 4 or 5 years of phytomanagement. Their effects on PTE transfers in plants varied depending on the species, levels of pollution and time. The study of microbial communities in tree roots revealed that the herbaceous cover and soil pollution had a significant impact on microbial composition whereas the amendments did not affect the microbial communities.

O avanço industrial e urbano associado ao aumento da produção dos bens de consumo resultou na geração de resíduos que, por muito tempo, foram descartados indiscriminadamente no ambiente, provocando danos quase sempre irreversíveis e de difícil recuperação. Dois experimentos foram conduzidos em solos contaminados por metais pesados, o primeiro devido ao descarte de produtos inorgânicos contendo grande carga de poluentes no solo; no segundo estudo a contaminação deve-se ao uso sucessivo de fungicidas contendo cobre em pomares cítricos do sul da Flórida. O primeiro estudo objetivou avaliar o uso de amenizantes orgânicos como mitigadores da toxicidade de bário, boro, cádmio, chumbo, cobre, níquel e zinco presentes no solo contaminado decorrente da adição de resíduo de sucata automobilística e avaliar o potencial fitoextrator do pinhão-manso (Jatropha curcas L.). Observou-se que o fornecimento da matéria orgânica na forma de turfas não amenizou a contaminação por metais pesados (Ba, Cd, Cu, Ni, Pb,Zn) e B; tal efeito pode ter ocorrido devido ao elevado pH deste solo mantido pelas práticas constantes de calagem. Os elementos apresentaram maior disponibilidade no solo ao longo das avaliações, exceto o boro que não apresentou significância. As plantas apresentaram sintomas de fitotoxicidade causados pelo elevado teor de boro e metais pesados no solo. A maior parte dos elementos metálicos se acumulou nos colmos e o boro nas folhas do pinhão manso, ou seja, a planta foi eficiente em translocar tais elementos para a parte aérea, situação desejável em uma fitoextratora. Ao final do experimento, os teores de Ba, Cd, Cu, Ni, Pb e Zn estavam mais disponíveis às plantas. O que indica que a matéria orgânica presente nas turfas mineralizou e tornou mais disponível estes metais pesados às plantas ao longo das avaliações. Pelos índices de transferência, de translocação e de remoção o pinhão manso foi viável somente para fitoextração de boro da área contaminada; estes índices também apontaram que o pinhão manso apresentou potencial para acumular B, Ba e Cd. O segundo experimento foi desenvolvido em casa de vegetacão com um argissolo coletado em uma área que tem recebido sucessivas aplicações de fungicidas a base de cobre, o que tem promovido o acúmulo significativo deste elemento nos solos sob produção de citros. O objetivo foi avaliar o potencial de fitoextração de cobre pelas plantas chinesas Splendens elsholtzia e Argyi elsholtzia para remover o excesso de cobre em solos contaminados devido a aplicação sucessiva de fungicidas cúpricos em pomares cítricos do sul da Flórida. A produção de massa seca de folhas, colmos e raízes e a concentração de cobre nos tecidos da Splendens elsholtzia foram superiores ao da espécie Argyi elsholtzia, o que indica que a Splendens elsholtzia é mais tolerante aos elevados níveis de cobre no solo. Assim, esta espécie pode ser indicada para programas de fitoextração em solos contaminados com cobre; entretanto, o índice de translocação do cobre indicou que as duas espécies não foram eficientes em translocar o cobre da raíz para parte aérea. / The industrial and urban progress associated with increased production of consumer goods has resulted in the generation of waste, which, for a long time, was indiscriminately discarded in the environment, causing damage usually irreversible to recover. Two experiments were conducted in soils contaminated with heavy metals: the first aimed at the disposal of products containing high loads of inorganic pollutants in the soil and the second focused on contamination due to the successive uses of fungicides containing copper in citrus groves of South Florida. The first study aimed to evaluate the use of organic soothers as mitigators of toxicity caused by barium, boron, cadmium, lead, copper, nickel and zinc in soil contaminated with waste resulting from the disposal of automobile scrap and to evaluate the phytoextraction potential of Jatropha (Jatropha curcas L.). It was observed that the supply of organic matter in the form of peat did not alleviate the contamination with heavy metals (Ba, Cd, Cu, Ni, Pb, Zn) and B, which may be attributed to the high pH of the soil due to constant practices of liming. The items showed higher availability in the soil during the evaluations, except for boron which showed no significance. The plants showed symptoms of phytotoxicity caused by high levels of boron and heavy metals in the soil. Most metallic elements are accumulated in the stems and boron in the leaves of Jatropha curcas, thus, the plant was efficient in the translocation of these elements to the shoot, a situation is desirable in phytoextraction. At the end of the experiment, the concentrations of Ba, Cd, Cu, Ni, Pb and Zn were more available to plants. This indicates that the organic matter present in the peat mineralized and made these heavy metals more available to plants. Considering the transfer rates of translocation and removal, the Jatropha was feasible only for phytoextraction of boron in the contaminated area, which shows that Jatropha has the potential to accumulate B, Ba and Cd. The second experiment was conducted in a greenhouse in an alfisol collected in an area that received repeated applications of copper-based fungicides, which promoted significant accumulation of this element in soils under citrus production. The objective was to evaluate the potential for phytoextraction of copper by the Chinese plants Splendens elsholtzia and Argyi elsholtzia to remove excess of copper in contaminated soils due to repeated application of copper-based fungicides in citrus groves of South Florida. The dry weight of leaves, stems and roots and the concentration of copper in the tissues of Splendens elsholtzia were higher than in Argyi elsholtzia, which indicates that the Splendens elsholtzia is more tolerant to high copper levels in the soil. Thus, this species may be indicated for phytoextraction of soils contaminated with copper; however, the rate of copper translocation indicated that the two species were not efficient to translocate copper from root to shoot.

Le développement de l’industrie et de l’agriculture a entraîné l’accumulation d’éléments métalliques dans les sols. Dans ces écosystèmes, la fraction vivante intervient de façon importante dans la modification de la rétention des contaminants. Parmi les techniques de décontamination, la phytoremédiation apparaît comme un outil de choix. Si un des inconvénients majeurs de cette technique réside dans des durées de traitement pouvant atteindre plusieurs années, l’ajout de micro-organismes couplé aux plantes améliorerait les prélèvements et réduirait les temps de décontamination. Cette étude s’est intéressée aux possibilités de développer des procédés de phytoremédiation associés à des bactéries productrices de sidérophores, molécules ayant une forte affinité pour le fer mais également pour d’autres métaux. Dans ce contexte, un système de complexité croissante, jusqu’au modèle complet comprenant les constituants du sol, les bactéries, les métaux contaminants et les plantes, a été étudié avec pour objectif la compréhension des processus intervenant dans ces différentes interactions. Ces travaux ont conduit, dans un premier temps, à la compréhension, notamment par une approche de biologie moléculaire, des interactions intervenant entre des minéraux du sol, des argiles et des oxy-hydroxydes de fer, et une bactérie productrice de sidérophores, Pseudomonas aeruginosa. Les résultats ont mis en évidence le rôle majeur de l’un de ces sidérophores, la pyoverdine, ainsi que du biofilm, dans la dissolution des minéraux par cette bactérie. Une étude en fluorimétrie et dosages des métaux a, quant à elle, montré que la pyoverdine était capable de complexer des métaux contaminants adsorbés sur les argiles ou présents dans la structure cristalline des oxy-hydroxydes de fer. Enfin, ces travaux ont abouti à la mise en place du système d’étude dans sa globalité. Si la pyoverdine ou les bactéries productrices de sidérophores n’ont pas amélioré le prélèvement par les plantes du cadmium et du nickel, des résultats prometteurs ont cependant été obtenus pour le cuivre. De plus, les bactéries productrices de sidérophores s’avèrent être des cibles intéressantes en phytostabilisation. / The industrial and agricultural development caused a metallic element accumulation in the soils. In these ecosystems, the living fraction significantly operates in the changes of contaminants retention. Among the decontamination techniques, the phytoremediation appears as a tool of choice. If one of major disadvantages of this technique is the long-term remediation process, the addition of microorganisms with the plants could enhance the uptakes and decrease the time to remediate. This work focused on the possibility to develop processes for siderophore-producing bacteria-assisted phytoremediation, siderophores being molecules with a high affinity for iron and also able to chelate other metals. In this context, a system with an increasing complexity until a complete model including the soil constituents, the bacteria, the contaminant metals and the plants, has been studied to understand the processes involved in these different interactions. The understanding of the interactions between the soil minerals, clays and iron oxydydroxides, and a siderophore-producing bacteria, Pseudomonas aeruginosa, have been first performed with, in particular, a molecular biology approach. These results have highlighted the major role of the one of siderophores, the pyoverdine, and also the biofilm in the mineral dissolution by this bacteria. Fluorimetry and metal quantification assays showed that the pyoverdine was able to chelate the contaminant metals adsorbed on the clays or present in the crystal structure of the iron oxyhydroxides. Lastly, the global system has demonstrated that if the pyoverdine or the siderophore-producing bacteria do not enhance the cadmium and nickel uptake by plants, promising results were obtained for copper. Moreover, siderophore-producing bacteria turn out to be interesting asset for the phytostabilization.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Introduction and objectives: Arbuscular mycorrhizal fungi and vermicompost may decrease the deleterious effects of copper on plants. The goal of the present study was to evaluate the effect of inoculation with the fungus Rhizophagus clarus and the addition of grape bagasse vermicompost on phytoremediation by Canavalia ensiformis of a sandy soil with high Cu concentration. Methods: Soil was contaminated with 100 mg Cu kg-1, fertilized with five levels of vermicompost, and cultivated with C. ensiformis with and without inoculation with Rhizophagus clarus. Availability of Cu and other nutrients in the soil and in the soil solution, shoot and root accumulation of Cu and other nutrients, plant growth, and Cu phytotoxicity using photochemical efficiency, concentration of photosynthetic pigments, and oxidative stress enzyme activities as indicators of Cu phytotoxicity were evaluated. Results: Phytostabilization showed better performance with the addition of the vermicompost level equivalent to 20 mg P kg-1 and in the presence of R. clarus. Phytoextraction was higher with the addition of the vermicompost level equivalent to 40 mg P kg-1 and without R. clarus inoculation. However, C. ensiformis was not a good phytoextractor. Conclusions: The system C. ensiformis vermicompost R. clarus exhibited potential for Cu phytostabilization in sandy soils. / Introdução e objetivos: Fungo micorrízico arbuscular e vermicomposto podem reduzir os efeitos deletéricos do cobre às plantas. O objetivo do trabalho foi avaliar o efeito da inoculação do fungo Rhizophagus clarus e da adição do vermicomposto de bagaço de uva na fitorremediação por Canavalia ensiformis de um solo arenoso com alto teor de Cu. Métodos: Solo foi contaminado com 100 mg Cu kg-1 e adubado com cinco doses de vermicomposto para o cultivo de C. ensiformis, com e sem a inoculação com Rhizophagus clarus. Foram avaliados a disponibilidade de Cu e outros nutrientes no solo e em solução, o acúmulo de Cu e dos outros nutrientes na parte aérea e nas raízes, o crescimento vegetal e a fitotoxicidade do Cu, através da eficiência fotoquímica, da concentração de pigmentos fotossintéticos e da atividade de enzimas do estresse oxidativo. Resultados: A fitoestabilização ocorre melhor na dose de vermicomposto equivalente a 20 mg P kg-1 e na presença do R. clarus. A fitoextração é maior na dose de vermicomposto equivalente a 40 mg P kg-1 e sem a inoculação do R. clarus, mas C. ensiformis não se apresenta como uma boa planta fitoextratora. Conclusões: O sistema C. ensiformis- vermicomposto- R.clarus tem potencial de aplicação na fitoestabilização de Cu em solos arenosos.