Made available in DSpace on 2014-06-11T19:23:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-12-11Bitstream added on 2014-06-13T20:10:44Z : No. of bitstreams: 1 badelmogollon_jej_me_jabo.pdf: 816174 bytes, checksum: 963bfca6b10bc3cd8911e28a30eae3c6 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Foi feita uma análise da variabilidade das propriedades químicas (pH-CaCl2, M.O., P em resina, K, Ca, SB, H+Al, T e V%) e físicas (Declividade, Densidade do solo) da camada orgânica superficial do solo, num fragmento de bosque tipo cerrado, localizado dentro de uma matriz de áreas de pastagem, na bacia média do rio Paraná. Os valores registrados indicaram uma deficiência geral dos nutrientes, tanto na área de pastagem, quanto do cerrado. Neste último, existe uma relação entre as propriedades físicas e químicas do solo e o relevo no terreno (p<0.05). Os valores das propriedades químicas apresentaram-se com menor dispersão nas áreas mais planas, com respeito às áreas côncavas ou convexas. Na área de pastagem não foi possível detectar padrão algum para a variabilidade nos valores encontrados. O maior risco de deterioro das propriedades estudadas, está, en teoria, na sua perda ao longo prazo por lixiviação, sobre tudo da fase trocável do K. A acidez do solo e troca de cátions são as variáveis mais afetadas pela atividade humana, e, por extenso, determinantes da vulnerabilidade ecológica no cerrado. / A variability analysis of the superficial soil organic layer chemical and physical properties in a fragment “cerrado” type, localized inside a matrix of pastures areas, in the Paraná River middle basin was done. Recorded values showed a general deficiency of nutrients in both pastures and “cerrado” areas. In the last one exists a relationship between the chemical and physical soil properties and the relief (p<0.05). Chemical properties showed values close to the expected for bed areas and smaller values from the expected in concave and convex areas. In the pasture areas there was no pattern of variability between the values. Ecologically, the “cerrado” area is under high vulnerable condition due to the antropic pressure that the pasture matrix exerts. In theory, the greater risk of the investigated properties is their lost in the long-term by lixiviation, especially in K (change fase). The soil acidity and the interchanging of cations are the more affected variables by the human activity and, therefore, they determinate the ecological vulnerability of the Cerrado.

O histórico de contaminação por metais no Vale do Rio Ribeira de Iguape é bem conhecido, com evidências de transporte destes contaminantes ao Complexo Estuarino Lagunar de Cananéia-Iguape (CELCI), adsorvidos ao material em suspensão. Assim, os metais podem alcançar o setor sul do CELCI, podendo acumular nos sedimentos e nos organismos filtradores. Neste estudo foi realizada uma avaliação de risco ecológico no CELCI associado à presença de metais oriundos das antigas áreas de mineração do Alto Ribeira, utilizando diferentes linhas de evidência. Os resultados foram avaliados de forma integrada, incluindo análises geoquímicas e biológicas (ensaios de toxicidade aguda, medidas de bioacumulação e biomarcadores bioquímicos em brânquias de bivalves). Os sedimentos apresentaram níveis moderados a altos de metais e toxicidade aguda, a qual foi associada, especialmente, com as concentrações de Cu, Pb e Zn. Da mesma forma estes metais foram encontrados em concentrações altas nos tecidos de bivalves. Os biomarcadores bioquímicos (MT, GSH, GST, GPx, GR, AChE, LPO e danos em DNA) indicaram a ocorrência de efeitos significativos nos bivalves. Portanto, os resultados mostram que os metais estão sendo carreados para a porção sul do estuário, causando bioacumulação e efeitos nos organismos aquáticos e, portanto, gerando riscos ecológicos para o CELCI. / The historic of contamination by metals in the Valley of Ribeira de Iguape River is well known, and there are evidences that these chemicals are carried to the Estuarine Complex of Cananeia-Iguape (ECCI), adsorbed on the suspended particles. Metals can thus reach the south of the ECCI, where they may accumulate in the sediments and filter feeding organisms. This study aimed to evaluate the ecological risks associated to the metals originated from the former mining areas of the upstream Ribeira de Iguape River, by using different lines of evidence, which included geochemical and biological analysis (acute toxicity tests, bioaccumulation and biochemical biomarkers in bivalves\' gills). The sediments presented moderate to high levels of metals and acute toxicity, which was correlated with the concentrations of metals (Cu, Pb and Zn). These elements were found in high concentrations in the bivalves soft tissues. The biochemical biomarkers (MT, GSH, GST, GPx, GR, AChE, LPO, and DNA damage) indicated the occurrence of significant effects in the bivalves. Therefore, the results showed that metals are carried into the South portion of the estuary, accumulating in the biota and causing negative effects to the aquatic organisms, producing thus ecological risks to the ECCI.

A contribuição deste trabalho é apresentar uma metodologia de avaliação de risco ecológico do ambiente aquático utilizando-se dados provenientes de programas de monitoramento ambiental. O estudo tem como cenário um trecho do Rio Jacuí, município de São Jerônimo – RS, Brasil, que foi avaliado através da aplicação de um programa de monitoramento ambiental. Consideraram-se como variável explicativa deste estudo, as evidências registradas nos compartimentos abióticos, água superficial e sedimento. As evidências químicas foram decorrentes da presença dos metais Hg, Pb e Zn e as evidências ecotoxicológicas de ensaios de toxicidade aquática com Ceriodaphinia dubia para água superficial e Hyalella azteca para sedimento. Consideraram-se como variáveis respostas as evidências biológicas compostas pelos dados de riqueza, índice de Shannon-Weaver, equitatividade e densidade numérica das espécies das comunidades zooplantônica e bentônica. O risco ecológico (Baixo, Médio e Alto) foi caracterizado pela associação à qualidade ambiental (Ótima, Alerta e Crítica), respectivamente, estabelecida pelas evidências registradas. Os resultados permitem considerar que é possível o uso de programas de monitoramento ambiental para avaliação de risco ecológico, se contiverem, além dos dados químicos e ecotoxicológicos exigidos pela legislação ambiental, dados do monitoramento da biota residente. / The contribution of this work is to present a methodology for ecological risk assessment in an aquatic environment using data derived from environmental monitoring programs. The location focused by this study was a segment of the Jacuí River, in the town of São Jerônimo – RS, Brazil, which was assessed by applying an environmental monitoring program. The evidence recorded from the abiotic compartments surface water and sediments was considered an explanatory variable. The chemical evidence stemmed from the presence of Hg, Pb and Zn, while the ecotoxicological evidence resulted from aquatic toxicity tests using Ceriodaphinia dubia for surface water and Hyalella azteca for sediments. The biological evidence from the Shannon-Weaver index, species richness, equitability and numerical density data in zooplanktonic and benthonic communities was considered the response variable. The ecological risk (Low, Medium, and High) was characterized by the association with environmental quality (Great, Warning, and Critical), established by the evidence recorded. The results have shown that it is possible to use environmental monitoring programs to evaluate of ecological risk assessment, if they have chemical and ecotoxicological data required by environmental laws, and monitoring data of resident biota.

D.Phil. / South Africa is the highest produce-producing and therefore the highest pesticide consumer on the African continent. Although greatly beneficial to the industry, indiscriminate and over usage of these agrochemicals pose a risk to the aquatic ecosystems through non-point source pollution. Data on these risks are limited in the developing countries such as Africa since limited environmental monitoring of pesticides is undertaken. This is due to technical, logistical and economical constraints in determining the links between exposure and effect on non-target organisms. Methods that are able to screen for and monitor pesticides that could pose a risk according to site-specific scenarios are therefore necessary. Economical and easy-to-use predictive models incorporated into Preliminary Risk Assessments (PRA’s) are useful in this regard and have been developed and applied globally to assist in estimating the probability of risks of pesticides associated with aquatic ecosystems. Currently no such risk assessment model is applied in South Africa for this purpose. The main aim of the present study was to present and assess the suitability of selected PRA models as preliminary screening tools for estimating potential pesticide exposure and associated effects within aquatic ecosystems. To achieve this, the primary objectives were to apply and validate these models for assessing predicted risks and to relate these to actual ecological hazards by monitoring the exposure and effects of selected pesticides that were identified as potentially posing a risk. It was hypothesised that the data determined by these models would elucidate the association between potential risks of pesticides and actual environmental impacts and could therefore be applied and validated for South African conditions. A framework was thus developed using multidisciplinary approaches to predict the risks of agricultural pesticides to non-target aquatic organisms and to validate these risks in an area known to have a high pesticide usage, namely the Crocodile (west) Marico catchment. This area is representative of a typical farming community in the subtropical central area of South Africa. It is a catchment area that exhibits high urban and agricultural usage, which has compromised the overall ecological integrity of the aquatic systems. The focus of the study was on the Crocodile (west) and Magalies Rivers and the associated irrigation canal network systems. The present study was based on integrating multidisciplinary techniques following the implementation of a tiered approach for assessing the ecological risks of selected pesticides known to be used within the Crocodile (west) Marico catchment. Tier 1 starts with the PRA SUMMARY xx assuming a relatively worst-case scenario by identifying pesticides most commonly used (through surveys) and estimating exposures posing a potential risk to the aquatic environment using the PRIMET (Pesticide Risks In the tropics to Man, Environment and Trade) model. The second tier can establish a more realistic characterisation of risk for the pesticide application scenarios of interest by using models such as PERPEST (Predicting the Ecological Risks of PESTicides), PEARL (Pesticide Emission Assessment of Regional and Local Scales), TOXSWA (TOXic substances in Surface Waters), or SSDs (Species Sensitivity Distributions). Higher tiers then include comparing the results from the PRA model predictions to the actual hazards of pesticides and can determine if these risk models are valid under South Africa conditions. This can be achieved using a combination of laboratory- and field-based monitoring assessments in the form of a triad approach (using chemical, toxicological and ecological assessments) to construct several lines-of-evidence (LoEs). The risk assessment process ends with a summary and integration of the data based on the multiple LoEs gathered during monitoring using a weight-of-evidence (WoE) approach.

M.Sc. (Geography) / Maputoland is one of the few remaining wilderness areas along the South African coast on which to base a progressive tourist industry. The area between Dog Point and Sodwana Bay was selected as the study area, as the area calls for responsible development. The area lends itself to various nature-orientated activities and therefore the development of a hiking trail will be investigated. Compliance with the following two principles is necessary in order to ensure the success of a hiking route: (a) the environment must be protected and (b) the environment must satisfy the needs of a hiker. Both the principles mentioned are taken into account in the application of Hugo and Bewsher's (1993) comprehensive trail development model. It is for this reason that the model is applied to designate the most suitable location for a hiking corridor. In order to identify a hiking corridor the five planning phases of the comprehensive trail development model must be applied. Identification of primary parameters that in conjunction form ecological units: When vegetation and geomorphological units, which can be represented spatially, are laid over one another, new units known as ecological units, are formed. These units are placed in order to suitability and divided into functional planning zones...

M.Sc. (Zoology) / Viticulture is an important agricultural practice in many countries. The long term use of pesticides in vineyards has resulted in increased concentrations of such pollutants in sediments, water and other environmental compartments. Mitigation measures in agriculture, especially vineyard agriculture, are a prerequisite to the sustained integrity of the natural environment, and specifically the aquatic environment. Mitigation presents itself in the form of water bodies, riparian buffer strips, ground vegetation cover, grassed field paths, natural or artificial wetlands and modification of pesticide application rate. However, to our knowledge no studies exist which highlight the state of dams related to viticulture or the use of mitigation measures, in South Africa. The study aimed to quantify the cumulative risk posed to dams on wine farms and the effect of pesticides (fungicides, herbicides and insecticides) on aquatic ecosystems while evaluating the use of mitigation measures in South African viticulture. Epilithic diatom community structure assessment and frustule abnormalities; zooplankton and macroinvertebrate community structure assessment, and characterization of mitigation measures were carried out at nine representative study sites on wine farms in the Western Cape, South Africa. Pesticide risk assessment models PRIMET and PERPEST were employed to assess the risk that pesticides pose at each site from available data. The Relative Risk Model was used to assess the risk posed to identified Risk Regions. Different risk categories were observed across the sites from PRIMET and PERPEST, ranging from no risk to high risk for specific pesticides and relative risk among the risk regions was assessed. Diatom community structure displayed spatial and temporal variability between sites as well as observable diatom frustule abnormalities due to pesticide input. Zooplankton and macroinvertebrate communities displayed variability spatially as well as temporally and this was linked to the presence of pesticides confirming the predictions from PRIMET, PERPEST and the RRM.

D.Phil (Aquatic Health) / Pesticides have been used to control and eliminate agricultural pests for many years thereby increasing crop yield in agriculture; however, the increasing human population worldwide has put increased pressure on agriculture to produce food. This is especially true in developing countries where the population growth has exceeded the predicted growth. Agriculture has therefore become more reliant on pesticides to increase the crop yield to meet the food demand. Many of the pesticides that are used in developing countries are not well studied in these countries and only limited information on their effects on the local environment is known. The information that is available is often from temperate regions and the effects of the pesticides in more arid, subtropical areas are not known. This is especially true in South Africa where a limited amount of studies on pesticides and their effects on the environment have been completed. The problem developing countries (including South Africa) face is the lack of funding which limit the studies on pesticides. Thus, a method was developed in Sri Lanka and Thailand whereby the risk and effects of pesticides to the environment, specifically non-target organisms, can be estimated using an international database which contains predominantly temperate data of pesticides. The first time this model was tested in South Africa was on the Crocodile River (West) Irrigation Scheme in the North West province. This model is initially dependant on the input of information from local farmers on the usage of pesticides. The data were then combined with secondary data on the pesticide characteristics to establish a preliminary risk posed by the pesticides. This risk could then be validated through biological monitoring and the actual pesticide values measured in the environment. This current study was initiated to test these probabilistic models in another part of South Africa with a more arid climate. The Vaalharts Irrigation Scheme (VHIS) comprises an area of 40 000ha where intensive agriculture activities take place and pesticide use is evident. The water for the irrigation scheme is transferred from a weir in the Vaal River to various irrigation canals and dams downstream. Water is then pumped out of the dams to irrigate the various crops. The runoff and drainage water is routed to drainage canals that return to the Harts River. The main crops in the area are wheat, maize and groundnuts, and a wide range of pesticides are used from the time the crops are planted until they are ready to be harvested. The current study was based on the Crocodile (West) River study in terms of the methodology followed, to further validate the use of the risk assessment methodology in southern Africa. Based on a situation analysis of the study area the following two hypotheses were formulated: the predictive and integrated risk models can be used to assess the ecological risk of pesticides when applied on the VHIS; and the risk information generated with these models can be communicated in an effective manner by using a Decision Support System (DSS).

Quantitative soil ingestion studies employing a mass balance tracer approach have been used to determine soil ingestion rate for use in human health risk assessments (HHRAs). Past studies have focused on soil ingestion in populations living in urban/suburban environments and the results have been highly variable. Moreover, there is a paucity of reliable quantitative soil ingestion data to support human health risk assessments of other lifestyles that may be predisposed to ingesting soil, such as indigenous populations following traditional lifestyles. Thus, the primary objective of the research was to determine if populations following lifestyles typical of traditional land use practices in rural or wilderness areas ingest more soil than populations living in urban or suburban environments. Further, the research investigated the use of alternative mass balance tracers, specifically isotopes of the 238U and 232Th decay series, to reduce soil ingestion estimate variability. Mass balance tracer methods were developed and validated in a pilot canine study, and methods using isotope tracers were adapted to permit quantification of sediment ingestion in the benthic fish Moxostoma macrolepidotum (Shorthead Redhorse Sucker). A pilot human soil ingestion study of 7 subjects from an Aboriginal community in British Columbia was conducted over a 3-week period. The mean soil ingestion rate calculated using the daily means of the 4 elemental tracers with the lowest food-to-soil ratios (i.e., Al, Ce, La, Si) was observed to be approximately 74 mg d-1 (standard deviation 91 mg d-1), The median soil ingestion rate was 60 mg d-1, and the 90th percentile was 196 mg d-1. These soil ingestion rate estimates are higher than those currently recommended for HHRAs of adults, and higher than those obtained in most previous studies of adults. However, the estimates are much lower than the earlier qualitative assessments for subsistence lifestyles (i.e., 330-400 mg d-1). The study results also demonstrated that isotopes of the 238U and 232Th decay series radionuclide are not reliable mass balance tracers for estimating soil ingestion in humans; however, they may be useful for quantifying soil and sediment ingestion in wildlife.

Este estudo teve como objetivo avaliar a interação entre substâncias húmicas e xenobióticos através de estudos ecotoxicológicos. O principal foco foi avaliar a resposta entre diferentes níveis tróficos em organismos aquáticos (fitoplanctônicos, zooplanctônicos, peixes e macroinvertebrados bentônicos) e terrestres (vegetais superiores, insetos e anelídeos) avaliando os efeitos diretos e indiretos das SH e de sua mistura com xenobióticos sobre os organismos. O reconhecido efeito das SH aumentarem ou reduzirem o efeito tóxico de algumas substâncias foi estudado. Os principais pontos para discussão são: a) SH podem reduzir ou estimular o crescimento algal (P. subcapitata); b) A presença de SH podem proteger os organismos contra efeitos tóxicos de metais, no entanto, a presença de Cd/Cu afeta negativamente o crescimento de C. xanthus. d) Em uma análise integrada de processos de remediação solo/água, a presença de SH afetou negativamente ou positivamente os efeitos tóxicos da atrazina em alguns organismos. A significância das SH como tecnologia é discutida. / This study focuses the interaction of humic substances and xenonbiotics, throw ecotixicological studies. The main point was quantify and qualify the ecotoxicological responses of several throphic levels of freshwater (algae, zooplankton, fishes and benthic organisms) and soil organisms (higth plants, insects and annelids) analyzing the direct and indirect effects of humic substances (HS) and their mixture on organisms. The recognized ability of HS on improve or reduce the toxic effect of same substances has been studied. The main points of discussion are: a) humic can be both reduce or stimulate the algal growth (P. subcapitata); b) The presence of HS can be protect aquatic organisms to negative effects of metals. However, the presence of mixture of Cd/Cu affect negatively the growth of C. xanthus; d) In a integrated analysis of remediation process in soil/water microcosm, the presence of HS displayed negative or positive effects on atrazine toxicity for some organisms. The value of humic technology was discussed.

Philosophiae Doctor - PhD / The increasing evidence of chemicals of emerging concern (CECs) in water bodies is causing major concern around the world because of their toxicological effects upon humans and aquatic organisms. The release of wastewater to the aquatic environment is most likely to introduce some trace levels of organic contaminants, some of which may be toxic, carcinogenic, or endocrine disruptors, as well as, persistent in the environment. These compounds are often persistent but not regularly monitored because they are mostly still excluded from environmental legislation. Their fate and persistence in the environment are not well understood