This thesis reviews literature relating both to the treatment of metal rich wastewaters by the use of constructed wetlands and the use of slurry analytical procedures for the determination of heavy metals in environmental micro-samples. A survey of metal contaminated wetland sites showed that aquatic plants maintain low levels of metals in aerial parts despite some very elevated sediment metal concentrations and extreme acidity. A series of greenhouse trials investigated the uptake of metals into aerial sections of Typha, Phragmites and Equisetum in long term hydroponic experiments. Phragmites was shown to accumulate zinc to a higher level than Typha. The toxicity of zinc supplied in the nutrient solution at 5 mg.dm-3 over long periods was found to limit the viability of such non-sediment based systems. A reliable routine analytical procedure was developed along with a program of quality control for the study of metal uptake into aquatic plants. A micro sampling technique, eminently suited for the analysis of small plant sections was developed. This technique uses ozone to ash the plant samples at a low temperature and following suspension in a liquid medium provides a sample ready for slurry determinations by a variety of analytical instrumentation. It is proposed that this method may also be suitable for the determination of metals in individual invertebrates and other zoological micro-samples as well as potential applications in the medical field.

Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-09-05T18:52:30Z No. of bitstreams: 1 LucianaAlves.pdf: 955999 bytes, checksum: 6c7aeb0334f4a832a4ef4f5804f697cc (MD5) / Made available in DSpace on 2017-09-05T18:52:30Z (GMT). No. of bitstreams: 1 LucianaAlves.pdf: 955999 bytes, checksum: 6c7aeb0334f4a832a4ef4f5804f697cc (MD5) Previous issue date: 2013-04-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Schistosomiasis is a parasitic disease caused by Schistosoma mansoni Sambon, that needs freshwater snails to complete their cycle. In Brazil, this disease affects thousands of people each year, being the Maranhão one of the states of higher occurrence. According to the World Health Organization, one of the measures need to reduce this disease is the control snails hosts through of the use of products known as molluscicides. Despite of the effectiveness of the use of niclosamide in this control, the high cost and environmental problems arising of this use has stimulated the search for new molluscicides safer, especially those of plant origin. Thus, this study aimed to perform a review of the plants and of the compounds of plant origin tested for the molluscicidal activity in Biomphalaria glabrata Say and analyze the chemical composition, the molluscicidal activity and toxicity of the latex of Euphorbia umbellata (Pax) Bruyns in adult fish species Danio rerio Hamilton-Buchanan. This dissertation was divided into two chapters. The chapter 1 consists of a review of the scientific studies which showed that extracts, fractions and compounds obtained of 200 plant species have already been tested by their molluscicidal activity and that 60, 75 and 95% of these, respectively, were actives according with the criteria established in this work. The chapter 2 aimed to perform a phytochemical screening and tests of toxicity in B. glabrata and D. rerio with the latex of E. umbellata. Phytochemical screening and evaluation of molluscicidal activity of the latex E. umbellata, cultivated plant in the state of Maranhão, revealed the presence of triterpenes and coumarins and high toxicity to B. glabrata. Experiments with D. rerio showed low toxicity of the latex. The results obtained showed the potential of natural products from plants, mainly the latex of E. umbellata, to produce molluscicidal agents that could be used to control of the schistosomiasis. It is expected that this work will contribute to the reduction in the number of cases of this disease in the state of Maranhão and for the preservation of plant studied. / A esquistossomose mansônica é uma doença parasitária causada pelo Schistosoma mansoni Sambon, que necessita de caramujos de águas doces para completar o seu ciclo. No Brasil, esta doença acomete milhares de pessoas anualmente, sendo o Maranhão um dos estados de maior ocorrência. Segundo a Organização Mundial de Saúde, uma das medidas necessárias para reduzir esta parasitose é o controle dos moluscos hospedeiros através do uso de produtos conhecidos como moluscicidas. Apesar do reconhecimento da eficácia do uso do produto químico niclosamida nesse controle, o alto custo e problemas ambientais decorrentes desta utilização vêm estimulando a pesquisa de novos moluscicidas mais seguros, destacando-se os de origem vegetal. Dessa forma, o presente trabalho objetivou realizar um levantamento das plantas e dos compostos de origem vegetal com estudos de atividade moluscicida em Biomphalaria glabrata Say bem como analisar a composição química, a atividade moluscicida e a toxicidade do látex de Euphorbia umbellata (Pax) Bruyns em peixes adultos da espécie Danio rerio Hamilton-Buchanan. Esta dissertação foi dividida em dois capítulos. O capítulo 1 consiste no artigo de revisão de literatura, onde foi possível verificar que extratos, frações e substâncias químicas de 200 espécies vegetais já foram avaliados quanto a esta atividade e que, 60, 75 e 95% destes, respectivamente, mostraram-se ativos segundo os critérios estabelecidos no trabalho. O capítulo 2 objetivou realizar uma triagem fitoquímica e testes de toxicidade em B. glabrata e D. rerio com o látex de E. umbellata. Prospecção fitoquímica e avaliação da atividade moluscicida do látex E. umbellata, planta cultivada no estado do Maranhão, revelaram a presença de triterpenos e cumarinas e a alta toxicidade contra B. glabrata. Os experimentos com D. rerio demonstraram baixa ictiotoxicidade do látex em estudo. Os resultados obtidos evidenciam o potencial dos produtos naturais de plantas, em especial do látex de E. umbellata, para a obtenção de agentes moluscicidas que possam ser empregados no controle da esquistossomose mansônica. Além do declínio no número de casos desta doença no estado do Maranhão, pretende-se que este trabalho contribua para a conservação da espécie vegetal estudada.