A field study conducted at Kidston Gold Mine, to evaluate the impact of arsenic and zinc from mine tailing to grazing cattle

The grazing trial at Kidston Gold Mine, North Queensland, was aimed specifically to assess the uptake of metals from the tailing and the potential for unacceptable contamination of saleable meat. Further aims included estimating metal dose rates and identifying potential exposure pathways including plant uptake of heavy metals, mine tailings adhered to plants and direct ingestion of mine tailing. It was found that of the 11 metals analysed (As, Zn, Co, Cd, Cr, Sn, Pb, Sb, Hg, Se and Ni) in the animal's liver, muscle and blood during the 8-month trial period, only accumulation of arsenic and zinc occurred. A risk assessment including these two metals was conducted to determine the potential for chronic metal toxicity and long-term contamination, using the estimates of metal dose rate. It was concluded that no toxicity or long-term contamination in cattle was likely at this site. Management procedures were therefore not required at this site; however, the results highlight percent ground cover and standing dry matter (DM) as important factors in decreasing metal exposure from direct ingestion of tailings and dust adhered to plants. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

A review on the role of duckweed in nutrient reclamation and as a source of animal feed

The family of lemnacae colloquially known as duckweed contains the world's smallest species of flowering plants (macrophytes). Aquatic and free-floating, their most striking qualities are a capacity for explosive reproduction and an almost complete lack of fibrous material. They are widely used for reducing chemical loading in facultative sewage lagoons, but their greatest potential lies in their ability to produce large quantities of protein rich biomass, suitable for feeding to a wide range of animals, including fish, poultry and cattle. Despite these qualities there are numerous impediments to these plants being incorporated into western farming systems. Large genetically determined variations in growth in response to nutrients and climate, apparent anti-nutritional factors, concerns about sequestration of heavy metals and possible transference of pathogens raise questions about the safety and usefulness of these plants. A clear understanding of how to address and overcome these impediments needs to be developed before duckweed is widely accepted for nutrient reclamation and as a source of animal feed.

A technique to assess small-scale heterogeneity of chemical properties in soil aggregates

A new method is presented which allows the separation of the soil aggregate exterior from the aggregate core. The method employs a combination of aggregate freezing with rapid separation of aggregate exteriors using ultrasonic energy. The factors influencing the thickness of the removed aggregate surface layer include water content of the aggregate prior to freezing, temperature difference between that of the frozen aggregate and that of the liquid it is submerged in during sonification, sonification time and energy, and the type of the immersion liquid. The success of the method and the thickness of the removed aggregate surface were examined using barium ( Ba2+) as a tracer. Barium ( as BaCl2) is rapidly absorbed by soil and is present at only very low levels in natural soils. Surface layers of 0.2 - 0.4 cm thickness were successfully removed from aggregates of 1 - 4 cm diameter. Two examples are given from soils in northern NSW to demonstrate the occurrence of small- scale heterogeneity in soil chemical properties. Compared with the surface fraction, a 4 - 7% higher calcium concentration was found in the core fraction of a clay loam soil ( Dermosol). Conversely, on a cracking clay soil ( Vertosol), atrazine concentration was around 15 times greater in the aggregate surface fractions compared with core fractions. Compared with the traditional estimation of soil chemical properties on homogenised bulk soil samples, it is suggested that separate analysis of aggregate surface and core fractions could provide useful additional information on the relationships between soil properties and environmental responses.

Cultivo in vitro de Crambe abyssinica Hochst. : germinação, micropropagação, estabilidade genética e anatomia foliar

Crambe (Crambe abyssinica) pertence à família Brassicaceae, originário da Etiópia e principalmente destinado à produção de forragem (30 a 32% de proteína bruta). Atualmente, tem sido bastante cultivado visando à extração de óleo vegetal. Com os atuais incentivos à busca de fontes de energias renováveis, o cultivo de crambe vem ganhando papel de destaque na produção de biodiesel por suas diversas vantagens, como: (a) rápido ciclo de vida (colhida em torno de 90 dias); (b) alta produção de biomassa; (c) alta produtividade de sementes (1000 e 1500 kg ha-1); (d) menor custo de produção em relação a outras fontes oleaginosas, como, canola, girassol e soja; (e) um percentual de óleo total na semente entre 32 e 38%, superando, por exemplo, a soja; (f) potencial de fitorremediação, eficiente na descontaminação de arsênio, cromo e outros metais pesados; e (g) elevado percentual de ácido erúcico (50 a 60%) sendo útil na indústria de plástico e lubrificante. Devido aos poucos trabalhos realizados com crambe, abre-se um vasto campo de investigações científicas que tenham como objetivo desenvolver as potencialidades dessa cultura e, consequentemente, melhorar os aspectos agronômicos e tecnológicos para seu emprego na indústria de biodiesel. Nesse contexto, as técnicas de cultivo in vitro foram importantes tanto para a propagação massal, quanto como ferramenta para uma possível aplicação de outras técnicas biotecnológicas, contribuindo para uma produção homogênea, fiel e em larga escala. Portanto, este trabalho teve como objetivo geral avaliar as condições mais favoráveis à germinação, estabelecimento in vitro e micropropagação de Crambe abyssinica Hochst., além de verificar possíveis alterações genéticas e anatômicas, possibilitando a regeneração e produção de plântulas viáveis. Para a germinação e estabecimento in vitro de crambe, as condições mais favoráveis foram em meio B5 ou WPM, na presença ou ausência de pericarpo e na presença de luz. Na micropropagação dessa espécie, uma frequência satisfatória de regeneração de brotos foi obtida a partir de segmentos apicais utilizados como explante em meio contendo 5 μM de BAP (6- benzilaminopurina), e o alongamento foi satisfatório com 1 μM de GA3 (ácido giberélico). Os marcadores moleculares ISSR (Inter-Simples Sequence Repeats) utilizados para a análise da estabilidade genética indicaram que o segmento apical de crambe é um explante confiável para a micropropagação de plantas geneticamente verdadeiras (true-to-tipe), ou seja, mantém a estabilidade genética. As diversas fontes de citocininas e concentrações utilizadas neste trabalho não promoveram mudanças, no sentido de alterar a organização e/ou a espessura em relação ao controle, e as alterações observadas na estrutura e espessura das folhas dos tratamentos de aclimatização prejudicaram o processo de estabelecimento da plântula ex vitro. Contudo, existe a necessidade de um enraizamento e aclimatização eficiente para completa propagação in vitro de crambe. Portanto, este protocolo de regeneração de plantas in vitro de crambe pode ser útil no processo de criação e desenvolvimento de novas cultivares em um tempo mais curto e no melhoramento genético usando explantes apicais.

Toxicological Assessment of Coated versus Uncoated Rubber Granulates Obtained from Used Tires for Use in Sport Facilities

Reuse of tire crumb in sport facilities is currently a very cost-effective waste management measure. Considering that incorporation of the waste materials in artificial turf would be facilitated if the rubber materials were already colored green, coatings were specifically developed for this purpose. This paper presents an experimental toxicological and environmental assessment aimed at comparing the obtained emissions to the environment in terms of polycyclic aromatic hydrocarbons (PAHs), heavy metals, and ecotoxicity for coated and noncoated rubber granulates. This study is a comprehensive evaluation of the major potential critical factors related with the release of all of these classes of pollutants because previous studies were not systematically performed. It was concluded that between the two types of coatings tested, one is particularly effective in reducing emissions to the environment, simultaneously meeting the requirements of adherence and color stability.

Application of GIS-based multi-criteria analysis for site selection of aquifer recharge with reclaimed water

Reclaimed water from small wastewater treatment facilities in the rural areas of the Beira Interior region (Portugal) may constitute an alternative water source for aquifer recharge. A 21-month monitoring period in a constructed wetland treatment system has shown that 21,500 m(3) year(-1) of treated wastewater (reclaimed water) could be used for aquifer recharge. A GIS-based multi-criteria analysis was performed, combining ten thematic maps and economic, environmental and technical criteria, in order to produce a suitability map for the location of sites for reclaimed water infiltration. The areas chosen for aquifer recharge with infiltration basins are mainly composed of anthrosol with more than 1 m deep and fine sand texture, which allows an average infiltration velocity of up to 1 m d(-1). These characteristics will provide a final polishing treatment of the reclaimed water after infiltration (soil aquifer treatment (SAT)), suitable for the removal of the residual load (trace organics, nutrients, heavy metals and pathogens). The risk of groundwater contamination is low since the water table in the anthrosol areas ranges from 10 m to 50 m. Oil the other hand, these depths allow a guaranteed unsaturated area suitable for SAT. An area of 13,944 ha was selected for study, but only 1607 ha are suitable for reclaimed water infiltration. Approximately 1280 m(2) were considered enough to set up 4 infiltration basins to work in flooding and drying cycles.

Comportamento materno e câncer de bexiga urinária: implicações da modulação de eixos hormonais e receptores de esteroides na fisiopatologia de lesões neoplásicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Remoção de metais usando casca de amendoim

Mestrado em Engenharia Química

Determinação preliminar de parâmetros construtivos de barreiras reactivas permeáveis com recurso a colunas para remediação de crómio com ferro zerovalente

Um dos principais problemas com que se deparam as sociedades actuais, e que é consequência da sua forma de se organizar prende-se com a mudança das características originais dos locais onde habitam e dos seus componentes como resultado das actividades humanas que transformam solos e águas em depósitos de resíduos. Entre as substâncias que são depositadas no meio físico, que requerem especial atenção, encontra-se o grupo dos metais pesados, uma vez que são considerados como perigosos pela sua toxicidade e potencial cancerígeno quando em contacto com populações ou ecossistemas. Destes metais, o crómio é um dos metais que requer especial atenção devido a sua relativa abundância como contaminante, e à periculosidade dos seus iões, em especial o Cr6+. Este trabalho pretende contribuir para o conhecimento dos fenómenos geoambientais associados à remediação de águas contaminadas com Cr6+ recorrendo ao ferro monovalente de forma a estabelecer parâmetros de aplicabilidade através de estudos laboratoriais baseados em ensaios em colunas.

Investigação em ambientes marinhos naturalmente acidificados

Jornadas "Ciência nos Açores – que futuro?", Ponta Delgada, 7-8 de Junho de 2013.

Application of wetland systems in the treatment of acid rock mine drainage

The presented work was conducted within the Dissertation / Internship, branch of Environmental Protection Technology, associated to the Master thesis in Chemical Engineering by the Instituto Superior de Engenharia do Porto and it was developed in the Aquatest a.s, headquartered in Prague, in Czech Republic. The ore mining exploitation in the Czech Republic began in the thirteenth century, and has been extended until the twentieth century, being now evident the consequences of the intensive extraction which includes contamination of soil and sub-soil by high concentrations of heavy metals. The mountain region of Zlaté Hory was chosen for the implementation of the remediation project, which consisted in the construction of three cells (tanks), the first to raise the pH, the second for the sedimentation of the formed precipitates and a third to increase the process efficiency in order to reduce high concentrations of metals, with special emphasis on iron, manganese and sulfates. This project was initiated in 2005, being pioneer in this country and is still ongoing due to the complex chemical and biological phenomenon’s inherent to the system. At the site where the project was implemented, there is a natural lagoon, thereby enabling a comparative study of the two systems (natural and artificial) regarding the efficiency of both in the reduction/ removal of the referred pollutants. The study aimed to assist and cooperate in the ongoing investigation at the company Aquatest, in terms of field work conducted in Zlaté Hory and in terms of research methodologies used in it. Thereby, it was carried out a survey and analysis of available data from 2005 to 2008, being complemented by the treatment of new data from 2009 to 2010. Moreover, a theoretical study of the chemical and biological processes that occurs in both systems was performed. Regarding the field work, an active participation in the collection and in situ sample analyzing of water and soil from the natural pond has been attained, with the supervision of Engineer, Irena Šupiková. Laboratory analysis of water and soil were carried out by laboratory technicians. It was found that the natural lagoon is more efficient in reducing iron and manganese, being obtained removal percentages of 100%. The artificial lagoon had a removal percentage of 90% and 33% for iron and manganese respectively. Despite the minor efficiency of the constructed wetland, it must be pointed out that this system was designed for the treatment and consequent reduction of iron. In this context, it can conclude that the main goal has been achieved. In the case of sulphates, the removal optimization is yet a goal to be achieved not only in the Czech Republic but also in other places where this type of contamination persists. In fact, in the natural lagoon and in the constructed wetland, removal efficiencies of 45% and 7% were obtained respectively. It has been speculated that the water at the entrance of both systems has different sources. The analysis of the collected data shows at the entrance of the natural pond, a concentration of 4.6 mg/L of total iron, 14.6 mg/L of manganese and 951 mg/L of sulphates. In the artificial pond, the concentrations are 27.7 mg/L, 8.1 mg/L and 382 mg/L respectively for iron, manganese and sulphates. During 2010 the investigation has been expanded. The study of soil samples has started in order to observe and evaluate the contribution of bacteria in the removal of heavy metals being in its early phase. Summarizing, this technology has revealed to be an interesting solution, since in addition to substantially reduce the mentioned contaminants, mostly iron, it combines the low cost of implementation with an reduced maintenance, and it can also be installed in recreation parks, providing habitats for plants and birds.

Análise de metais em infusões de chás e ervas aromáticas por espectrofotometria de absorção atómica de alta resolução com fonte contínua

Actualmente tem-se verificado um grande aumento na procura e a utilização de produtos naturais contendo extractos de algas, com fins medicinais, sendo cada vez maior a diversidade de oferta desses produtos, vendidos em ervanária e afins. A bibliografia tem mostrado que as algas têm capacidade de acumulação de metais pesados. As algas, sendo organismos aquáticos, estão sujeitas a contaminações dos locais (não identificados) de onde provêm. O controlo e fiscalização para estes produtos é praticamente inexistente. O objectivo deste projecto foi o desenvolvimento de metodologias analíticas com vista à quantificação de metais em infusões de chás e ervas aromáticas. Foram analisadas 9 amostras: uma de chá verde, uma de chá preto, uma infusão de lima, uma de camomila, uma mistura de chá com ervas e quatro misturas contendo algas. A espectrofotometria de absorção atómica é o método de referência para a análise de metais. Neste trabalho foi utilizado um espectrofotómetro de absorção atómica com fonte de radiação contínua e monocromador de alta resolução. Sendo esta uma tecnologia inovadora foi necessário desenvolver metodologias para os métodos de análise. A atomização em chama foi a técnica utilizada para a quantificação do cálcio, potássio, magnésio, manganês e sódio. A atomização electrotérmica foi usada para o cádmio, cobalto, crómio, cobre, níquel e chumbo. Tendo em conta os limites legislados (Decreto-Lei Nº306/2007 de 27 de Agosto) obtiveram-se teores preocupantes para o níquel (iguais ou superiores ao limite legislado) em todas as amostras analisadas e para o manganês em duas das amostras (chá verde e chá preto). Todas as amostras contendo algas apresentaram teores de Ca, Mg e Na superiores aos das restantes. Para os restantes elementos não foi possível relacionar as concentrações com a composição das infusões, em particular a presença de algas.

Efeito de metais pesados na alga Pseudokirchneriella subcapitata

O impacto dos metais pesados em ambientes aquáticos, incluindo águas residuais, é vulgarmente determinado através de testes de toxicidade. A microalga Pseudokirchneriella subcapitata é usada nos métodos de toxicidade recomendados por organismos Internacionais como a EPA (Environmental Protection Agency) e a OCDE (Organização para a Cooperação e Desenvolvimento Económico). O presente trabalho teve como objectivo avaliar o impacto do cádmio e do zinco no crescimento, na autofluorescência e na actividade metabólica da alga P. subcapitata. Para tal, a alga, em fase exponencial de crescimento, foi inoculada no meio de cultura contendo Cd (150, 500 ou 700 nmol/l) ou Zn (300, 1800 ou 6000 nmol/l). A concentração mais baixa de Cd e Zn não provocou qualquer efeito inibitório. Para uma concentração intermédia de Cd e Zn, observou-se uma redução do crescimento, ao fim de 72 h, de 63 e 50 %, respectivamente. No caso da concentração mais elevada de Cd e de Zn, observou-se uma redução do crescimento, ao fim de 72 h, de 83 e 97 %, respectivamente. A perda de autofluorescência da alga, devido à presença de Cd e de Zn, seguiu um padrão similar ao efeito sobre o crescimento. Resultados preliminares mostraram que a exposição das células de P. subcapitata a 700 nmol/ de Cd, durante 1h, induziu uma inibição da actividade esterásica de 52 %, enquanto que a incubação com 6000 nmol/l de Zn, durante 6 h, provocou uma redução da actividade esterásica de ~ 50 %. Em conclusão, os resultados obtidos mostram que o Cd é mais tóxico que o Zn para a alga P. subcapitata. A perda de autofluorescência, devido à exposição aos metais pesados em estudo, ocorreu segundo um padrão similar ao efeito inibitório sobre o crescimento. O Cd e Zn provocaram uma rápida perda (no espaço de 6 h) da actividade esterásica. Estes resultados sugerem que a avaliação da actividade esterásica da alga P. subcapitata poderá constituir um indicador sensível na avaliação da toxicidade.

Toxicological Assessment of Coated versus Uncoated Rubber Granulates Obtained from Used Tires for Use in Sport Facilities

Reuse of tire crumb in sport facilities is currently a very cost-effective waste management measure. Considering that incorporation of the waste materials in artificial turf would be facilitated if the rubber materials were already colored green, coatings were specifically developed for this purpose. This paper presents an experimental toxicological and environmental assessment aimed at comparing the obtained emissions to the environment in terms of polycyclic aromatic hydrocarbons (PAHs), heavy metals, and ecotoxicity for coated and noncoated rubber granulates. This study is a comprehensive evaluation of the major potential critical factors related with the release of all of these classes of pollutants because previous studies were not systematically performed. It was concluded that between the two types of coatings tested, one is particularly effective in reducing emissions to the environment, simultaneously meeting the requirements of adherence and color stability.

Survey of trace elements (Al, As, Cd, Cr, Co, Hg, Mn, Ni, Pb, Se, and Si) in retail samples of flavoured and bottled waters

Concentrations of eleven trace elements (Al, As, Cd, Cr, Co, Hg, Mn, Ni, Pb, Se, and Si) were measured in 39 (natural and flavoured) water samples. Determinations were performed using graphite furnace electrothermetry for almost all elements (Al, As, Cd, Cr, Co, Mn, Ni, Pb, and Si). For Se determination hydride generation was used, and cold vapour generation for Hg. These techniques were coupled to atomic absorption spectrophotometry. The trace element content of still or sparkling natural waters changed from brand to brand. Significant differences between natural still and natural sparkling waters (p<0.001) were only apparent for Mn. The Mann–Whitney U-test was used to search for significant differences between flavoured and natural waters. The concentration of each element was compared with the presence of flavours, preservatives, acidifying agents, fruit juice and/or sweeteners, according to the labelled composition. It was shown that flavoured waters generally increase the trace element content. The addition of preservatives and acidifying regulators had a significant influence on Mn, Co, As and Si contents (p<0.05). Fruit juice can also be correlated to the increase of Co and As. Sweeteners did not provide any significant difference in Mn, Co, Se and Si content.