The negative effects of hazardous substances and possible measures that can be taken are evaluated in the environmental risk analysis process, consisting of risk assessment, risk communication and risk management. Uncertainty due to lack of knowledge and natural variability are always present in this process. The aim of this thesis is to evaluate some tools as well as discuss the management of uncertainty and variability, as it is necessary to treat them both in a reliable and transparent way to gain regulatory acceptance in decision making. The catalytic effects of various metals on the formation of chlorinated aromatic compounds during the heating of fly ash were investigated (paper I). Copper showed a positive catalytic effect, while cobalt, chromium and vanadium showed a catalytic effect for degradation. Knowledge of the catalytic effects may facilitate the choice and design of combustion processes to decrease emissions, but it also provides valuable information to identify and characterize the hazard. Exposure factors of importance in risk assessment (physiological parameters, time use factors and food consumption) were collected and evaluated (paper II). Interindividual variability was characterized by mean, standard deviation, skewness, kurtosis and multiple percentiles, while uncertainty in these parameters was estimated with confidence intervals. How these statistical parameters can be applied was shown in two exposure assessments (papers III and IV). Probability bounds analysis was used as a probabilistic approach, which enables separate propagation of uncertainty and variability even in cases where the availability of data is limited. In paper III it was determined that the exposure cannot be expected to cause any negative health effects for recreational users of a public bathing place. Paper IV concluded that the uncertainty interval in the estimated exposure increased when accounting for possible changes in climate-sensitive model variables. Risk managers often need to rely on precaution and an increased uncertainty may therefore have implications for risk management decisions. Paper V focuses on risk management and a questionnaire was sent to employees at all Swedish County Administrative Boards working with contaminated land. It was concluded that the gender, age and work experience of the employees, as well as the funding source of the risk assessment, all have an impact on the reviewing of risk assessments. Gender was the most significant factor, and it also affected the perception of knowledge. / Negativa effekter orsakade av skadliga ämnen och möjliga åtgärder bedöms och utvärderas i en miljöriskanalys, som kan delas i riskbedömning, riskkommunikation och riskhantering. Osäkerhet som beror på kunskapsbrist samt naturlig variabilitet finns alltid närvarande i denna process. Syftet med avhandlingen är att utvärdera några tillvägagångssätt samt diskutera hur osäkerhet och variabilitet hanteras då det är nödvändigt att båda hanteras trovärdigt och transparent för att riskbedömningen ska vara användbar för beslutsfattande. Metallers katalytiska effekt på bildning av klorerade aromatiska ämnen under upphettning av flygaska undersöktes (artikel I). Koppar visade en positiv katalytisk effekt medan kobolt, krom och vanadin istället katalyserade nedbrytningen. Kunskap om katalytisk potential för bildning av skadliga ämnen är viktigt vid val och design av förbränningsprocesser för att minska utsläppen, men det är också ett exempel på hur en fara kan identifieras och karaktäriseras. Information om exponeringsfaktorer som är viktiga i riskbedömning (fysiologiska parametrar, tidsanvändning och livsmedelskonsumtion) samlades in och analyserades (artikel II). Interindividuell variabilitet karaktäriserades av medel, standardavvikelse, skevhet, kurtosis (toppighet) och multipla percentiler medan osäkerhet i dessa parametrar skattades med konfidensintervall. Hur dessa statistiska parametrar kan tillämpas i exponeringsbedömningar visas i artikel III och IV. Probability bounds analysis användes som probabilistisk metod, vilket gör det möjligt att separera osäkerhet och variabilitet i bedömningen även när tillgången på data är begränsad. Exponeringsbedömningen i artikel III visade att vid nu rådande föroreningshalter i sediment i en badsjö så medför inte bad någon hälsofara. I artikel IV visades att osäkerhetsintervallet i den skattade exponeringen ökar när hänsyn tas till förändringar i klimatkänsliga modellvariabler. Riskhanterare måste ta hänsyn till försiktighetsprincipen och en ökad osäkerhet kan därmed få konsekvenser för riskhanteringsbesluten. Artikel V fokuserar på riskhantering och en enkät skickades till alla anställda som arbetar med förorenad mark på länsstyrelserna i Sverige. Det konstaterades att anställdas kön, ålder och erfarenhet har en inverkan på granskningsprocessen av riskbedömningar. Kön var den mest signifikanta variabeln, vilken också påverkade perceptionen av kunskap. Skillnader i de anställdas svar kunde också ses beroende på om riskbedömningen finansierades av statliga bidrag eller av en ansvarig verksamhetsutövare.

Orientador: Mara Akie Iritani, Sueli Yoshinaga Pereira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociencias / Made available in DSpace on 2018-08-06T16:31:54Z (GMT). No. of bitstreams: 1 Couto_MariaLuizaTeixeira_M.pdf: 3706543 bytes, checksum: f150990d169a1b1034d761a8027c8f53 (MD5) Previous issue date: 2006 / Resumo: A metodologia de Avaliação do Risco é uma das ferramentas de gestão que possibilita encontrar uma solução sustentável considerando a proteção da saúde humana e a remediação de áreas contaminadas. A metodologia de Avaliação do Risco foi desenvolvida pela agência ambiental americana (U.S.EPA) e tem sido a base para aplicação em diversos outros países. Esta metodologia tem como princípio a determinação da probabilidade de ocorrência de efeitos adversos à saúde humana em função do cenário ao qual um receptor está exposto. Estabelece uma seqüência lógica de etapas a serem cumpridas e entre elas temos a quantificação dos riscos potenciais associados às características da população potencialmente exposta, denominadas de fatores de exposição. CETESB utilizou a metodologia de Avaliação do Risco para a determinação dos Valores de Intervenção para solos, que são valores de referência que orientam a classificação de uma área como contaminada. A CETESB, na ausência de dados característicos da população paulista e mesmo brasileira, utilizou fatores de exposição de fontes reconhecidas internacionalmente. Tendo como referência essas considerações, este trabalho foi idealizado em torno de três objetivos principais: (a) realizar uma revisão abrangente das informações recentes no campo de estudos geográficos nacionais e dados internacionais com a perspectiva de consolidar os fatores de exposição para a população paulista e, secundariamente, para a brasileira, (b) analisar a sensibilidade desses novos fatores de exposição frente aos Valores de Intervenção consolidados pela CETESB em 2001 para o Benzeno, Endrin e Níquel considerando os cenários de exposição agrícola, residencial e industrial, e (c) propor valores de fatores de exposição para utilização seja no calculo de novos Valores Orientadores do Estado de São Paulo como no processo de Avaliação do Risco à saúde humana aplicada as áreas contaminadas. Os fatores de exposição foram atualizados através da pesquisa em bancos de dados e literaturas e estimados com base em equações matemáticas especificas, quando pertinentes. A análise de sensibilidade foi realizada calculando-se as doses de ingresso e os valores de risco para as substâncias selecionadas, utilizando o modelo CSOIL e o mesmo procedimentos utilizado pela CETESB para derivação dos Valores de Intervenção. Os resultados mostraram que dentre os parâmetros de exposição avaliados, o peso corpóreo, a taxa de inalação e as taxas de ingestão de solo e água mostraram maior influência nos valores de risco final calculado. A magnitude da influência de cada fator depende das características físico-químicas e o compartimento alvo do contaminante. A avaliação do impacto destes fatores de exposição nos Valores de Intervenção mostra que não haveria alteração para o Benzeno e para o Níquel no cenário residencial. O maior impacto seria no cenário industrial. cujas concentrações aumentariam cerca de 50%. causado principalmente pela exclusão da criança como receptor. No cenário agrícola haveria um aumento de aproximadamente 10% em relação aos valores atuais de intervenção. Este estudo mostra que, apesar de não haver um impacto numérico nos valores de risco calculados, a variação dos fatores de exposição pode afetar de forma significativa os Valores de Intervenção, que foi o exemplo usado neste estudo, mas também nos estudos caso a caso e em outros valores de referência utilizados no gerenciamento de áreas contaminadas no Estado de São Paulo. Há a necessidade de reavaliação constante dos fatores de exposição sempre que forem publicados novos dados e, mais especificamente, para a população paulista, que possui comportamento e características distintas do restante do país / Abstract: The Risk Assessment methodology is a management toei which allows the finding of a sustainable solution considering human health and remediation of contaminated areas. The Risk Assessment methodology was developed by the Environment Protection Agency (EPA) of USA and has been the base for application in many other countries. This methodology is based on adverse effect occurrence probability's determination, given the scenario the that the receptor is exposed. It establishes a logical sequence of steps to be followed, among those, the potential risk quantification associated to the exposed population characteristics, called Exposure Factors. CETESB has used the Risk Assessment methodology to determine Intervention Values for soils, which are reference values to classify an area as contaminated. CETESB, faced a lack of data for São Paulo's and also Brazilian population characteristics, therefore used Exposure Factors of known international sources. Taking into account the mentioned considerations, this project was developed having 3 mains goals: (a) to make a broad revision of recent information in national geographic studies and international data, aiming to consolidate data for São Paulo's population, and secondarily for brazilian population; (b) to analyze these new factors' sensibility to Intervention Values consolidated by CETESB in 2001, to Benzene, Endrin and Nickel, considering agricultura!, residential and industrial scenarios, and (c) to propose Exposure Factors to be used in the new Orientation Values in the State of São Paulo as well as in the human health Risk Assessment process applied in contaminated areas. The Exposure Factors were updated through research in databases and literature sources, and were estimated based on specific mathematic equations, when appropriate. The sensibility analysis was carried out calculating intake doses and Risk values for the selected substances, using the CSOIL model and the same procedures used by CETESB to derivate Intervention Values. The results show that among the assessed parameters, body weight, air intake rate, and water and soil intake rate have the greater influence at the values of the calculated final risk. The magnitude of each factor depends on physical-chemical characteristics and contaminant's target compartment. The impact assessment of these Exposure Factors shows that there would not be changes for Benzene and Nickel in residential scenarios. The greater impact would be in the Industrial scenario, which concentrations would raise around 50%, caused mainly by the exclusion of children as receptors. In the agricultural scenario, there would be a raise of approximately 10%, related to the current intervention values. This study shows that, despite there is no numeric impact on the calculated risk values, the Exposure Factors variation may affect in a significant way the Intervention Values, that was the example used in this study, and also in studies of specific cases and in other reference values used in the management of contamínated areas in the State of São Paulo. A constant reassessment for the exposure factors is needed, whenever new data are published, and more specific, for São Paulo's population, which has different characteristics and behaviors from the rest of Brazil / Mestrado / Administração e Politica de Recursos Minerais / Mestre em Geociências

Syfte: Syftet med detta projekt var att utvärdera kvaliteten på de digitala röntgenbilder som genereras med en On-Board imager® (OBI), monterad på en medicinsk linjäraccelerator på radioterapiavdelningen på Karolinska Universitetssjukhuset. Dessa kilovoltbilder används för att verifiera patientens position på behandlingsbordet, inför behandling, för att reducera risken att friskvävnad bestrålas i onödan. Detta utförs genom en online ortogonal 2D-2D matchningsteknik innan strålningen leveras. Material och metoder: OBI-system, utvecklad av Varian Medical System, erbjuder en protokoll med exponeringsparametrar för att hjälpa användaren att välja lämpliga inställningar för exempelvis lämplig rörström och spänning under bildtagningen de digitala kilovoltbilderna. Under detta projekt skapades flera testbilder tagna med ändrade exponeringsparametrarna i de befintliga protokollen. Dessa testbilders kontrast bedömdes sedan och jämfördes med bilder tagna med de förinställda parametrar från Varians protokoll. Resultat och slutsats: En utvärdering av de experimentella testbilderna, i jämförelse med bilder skapade med det befintliga protokollet, visade att en justering av exponeringsfaktorer inte leder till något signifikant förbättring av bildernas kontrast. / Purpose: The purpose of this project was to evaluate the quality of kilo Voltage- digital radiography images that are provided by an On-Board imager® (OBI) mounted on a medical linear accelerator at the Radiotherapy department of Karolinska University Hospital. The digital kV-images are used to verify patient position on the treatment table, in order to reduce healthy tissue irradiation, using an online orthogonal set of 2D-2D matching technique, before the treatment delivery. Material and methods: The OBI- system elaborated by Varian Medical System offers an exposure factor protocol in order to help users to choice proper exposure factors, as proper tube current and tube voltage, during acquisition of kV-images. In this project several test images were performed by changing the exposure factors. Further the test images quality regarding, quality index contrast, was assessed and compared with the image performed by the existent Varian protocol. Result and Conclusion: Evaluation of the tests images shows that changing of the exposure factors doesn’t result in any significant improvement of kV-images contrast as compared to images created with the existent protocols parameters.