Submitted by LEANDRO GOMES DE FREITAS (legfreitas_br@yahoo.com.br) on 2017-05-16T03:49:19Z No. of bitstreams: 1 FREITAS,L.G._MESTRADO_HRSC_CH4.pdf: 28183033 bytes, checksum: 7752fe6e8f1336ebae2d7abc6db48c10 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-05-16T14:56:51Z (GMT) No. of bitstreams: 1 freitas_lg_me_rcla.pdf: 28183033 bytes, checksum: 7752fe6e8f1336ebae2d7abc6db48c10 (MD5) / Made available in DSpace on 2017-05-16T14:56:51Z (GMT). No. of bitstreams: 1 freitas_lg_me_rcla.pdf: 28183033 bytes, checksum: 7752fe6e8f1336ebae2d7abc6db48c10 (MD5) Previous issue date: 2017-03-24 / Os riscos associados à intrusão de gases e vapores do solo em edificações estão ganhando crescente interesse da sociedade, principalmente pelos possíveis danos à saúde humana ou até mesmo por explosões. Na região metropolitana de São Paulo, estudos ambientais vêm relatando com frequência a ocorrência de gás metano (CH4) no subsolo, gerando preocupações sociais, políticas e econômicas. Uma forma inovadora de otimizar o diagnóstico dessas áreas e gerar Modelos Conceituais mais consistentes, se dá com a utilização de técnicas de investigação de alta resolução, como o Membrane Interface Probe (MIP). Nesse contexto, foi conduzido um estudo para avaliar o potencial do MIP, associado a outras técnicas de investigação, para o diagnóstico geoambiental de uma área com a ocorrência de gás metano no subsolo. A área de estudo foi o campus da USP Leste, no município de São Paulo. O estudo foi realizado em três etapas. Na primeira, foram realizados testes de bancada para a obtenção de curvas de resposta do detector de ionização por chama (FID) do sistema MIP para diferentes misturas gasosas, com diferentes temperaturas de aquecimento da sonda. Na segunda etapa foram realizados os ensaios de campo com o MIP e com as seguintes técnicas auxiliares: Soil Color Optical Screening Tool (SCOST); amostragem de gases do solo com o sistema Post Run Tubbing (PRT); e, amostragem de solo por sondagens direct push. Na terceira etapa foram realizadas as análises laboratoriais das amostras de solo coletadas. Os resultados obtidos foram apresentados por meio de perfis e seções representativas da área de estudo. Nos ensaios de bancada, todas as curvas de resposta mostraram alta correlação entre as respostas do FID e as concentrações de CH4 das amostras. Os perfis obtidos em campo pelo sensor de condutividade elétrica do MIP, bem como os perfis de cores obtidos pelo SCOST, apresentaram boa correlação qualitativa com as descrições litológicas e com os perfis granulométricos, auxiliando na caracterização litoestratigráfica. Os ensaios MIP confirmaram a alta sensibilidade da ferramenta para a detecção de CH4, principalmente com a sonda aquecida, possibilitando o mapeamento de acumulações de biogás no subsolo. A amostragem com o PRT confirmou a existência de concentrações de até 77% v/v de CH4 nas camadas de depósitos tecnogênicos. Já as análises de teor de matéria orgânica e fração de carbono orgânico mostraram a presença de camadas com elevado teor orgânico e alto potencial metanogênico, principalmente nas camadas de argila orgânica em meio aos sedimentos quaternários. Conclui-se que o MIP demonstra um grande potencial para a caracterização em alta resolução de áreas com ocorrência de gás metano no subsolo e que as técnicas auxiliares forneceram informações importantes para apoiar a interpretação e a validação dos resultados obtidos. / The risks associated with soil gases and vapor intrusion in buildings are gaining increasing attention in our society, mainly because of possible harm to human health or even explosions. In São Paulo Metropolitan Area, environmental studies have frequently reported methane (CH4) in the subsoil, causing social, political and economic concerns. An innovative approach to optimize site assessment for these cases and generate more consistent conceptual site models (CSM), is through the application of high resolution site characterization (HRSC) tools, as the Membrane Interface Probe (MIP). In this context, a study was carried out to evaluate the potential of the MIP, associated with other subsurface investigation techniques, for the geoenvironmental diagnosis of an area with methane gas occurrence in the subsoil. The study area was the university campus of USP Leste, at São Paulo city. The study was performed in three stages, including laboratory and field procedures. On the first one, bench tests were performed to obtain response curves of the MIP’s Flame Ionization Detector (MIP/FID) for different gas mixtures, with variable probe heating temperatures. On the second stage, MIP tests were performed in the field, with the following auxiliary techniques: Soil Color Optical Screening Tool (SCOST); soil gas sampling with the Post Run Tubbing (PRT) system; and the direct push whole core soil sampling. The third and last stage consisted of laboratory analysis of the soil samples. The results of the bench tests showed very strong correlations between the FID’s response and the CH4 concentration of the samples. The profiles obtained on the field by the MIP’s electrical conductivity sensor and by the SCOST showed good qualitative correlation with the lithological descriptions and with the granulometric profiles, supporting the lithostratigraphic characterization. The MIP/FID results confirmed its high sensitivity to CH4 detection, especially with the heated probe, enabling the mapping of biogas accumulations in the subsurface. The PRT gas sampling confirmed methane’s concentrations as high as 77% v/v in the landfill layers. The organic matter analysis showed high organic content layers with great methanogenic potential, especially in the organic clay layers of the quaternary sediments. It was concluded that MIP has a great potential for the high resolution characterization of sites with methane gas occurrence and the auxiliary techniques also provided valuable information to support the interpretation and validation of the results.

[pt] Esta dissertação apresenta os resultados de duas técnicas de investigação em alta resolução: investigação passiva de vapores do solo e investigação com o uso de Membrane Interface Probe (MIP), em uma área de interesse com contaminação por hidrocarbonetos, localizada no município de Duque de Caxias/RJ. O processo de gerenciamento ambiental iniciou-se em 2012 na área e contemplou as etapas do gerenciamento de áreas contaminadas preconizadas nas legislações vigentes. Os resultados obtidos a partir das investigações tradicionais foram insuficientes para a obtenção da compreensão dos aspectos físicos e geoquímicos necessária para o sucesso das fases de diagnóstico e, consequentemente, da remediação. Portanto, duas investigações em alta resolução foram conduzidas com o objetivo de refinar o modelo conceitual de forma a atender adequadamente a Resolução CONAMA número 420/09 e Resolução CONEMA número 44/12, permitindo ações futuras mais eficientes. A investigação passiva de vapores do solo utilizou amostradores compostos por materiais adsorventes granulares, encapsulados em uma membrana microporosa hidrofóbica e quimicamente inerte que permite a difusão dos vapores presentes no meio. Os resultados, fornecidos em massa, representam qualitativamente a presença de contaminação no subsolo. O MIP é uma ferramenta de direct push com medição em tempo real, que mapeia a presença da contaminação tanto em meios insaturados quanto saturados inconsolidados. A partir dos resultados integrados, foi possível constatar que a distribuição de VOCs em água subterrânea ocorre de forma descontínua ao longo da área, sendo possível identificar cinco hot-spots distintos e suas diferentes áreas fonte, incluindo uma região com presença de LNAPL. / [en] The sources of contaminated sites are related to several factors such as the lack of knowledge of safe procedures for handling hazardous and / or toxic substances, disrespect to these safe procedures and the occurrence of accidents or leaks during industrial processes, transportation or storage of unprocessed materials and products. In addition, contamination is usually associated with the exploration of natural resources and with the expansion of the industry and/or agrarian activities, which have happened, and are still happening, at the cost of high environmental and social risks. A contaminated site is considered a risk, since its existence can generate several problems such as damages to health, impairment of the quality of water resources, restrictions on land use and damage to public and private property, and damage to the environment. These situations, in general, involve complex risks with regard to the effects of exposure to contaminants on human health (CETESB, 2013), and may have short -, medium - or long-term effects.

[pt] A atual situação de inconformidade de grande parte do Brasil em relação às diretrizes ambientais estabelecidas através da Resolução CONAMA número 420/2009 deixa claro os muitos desafios ainda existentes no âmbito do gerenciamento de áreas contaminadas. A análise de um caso real de remediação de uma planta industrial localizada no estado do Rio de Janeiro mostra como técnicas tradicionais de investigação ambiental, hoje consideradas ferramentas limitadas, foram e ainda são a principal base utilizada para a coleta de dados e subsequente tomada de decisões acerca do gerenciamento da área. O site em questão teve sua investigação ambiental iniciada ao final dos anos 90, realizada principalmente através de múltiplas campanhas de amostragem de solo e instalação de poços de monitoramento, identificando NAPLs (Non-aqueous phase liquids) como contaminantes de interesse. A planta industrial permanece sob intervenção há mais de dez anos sem aplicação de novas ferramentas de caracterização ambiental para aprimoração do modelo conceitual da área (CSM). A recente perda de eficiência do sistema de extração bifásica utilizado no local levou à implementação de técnicas de biorremediação estimulada in situ. Relatórios de desempenho mostram eficácia mais lenta do que o previsto, o que pode indicar um CSM deficiente em informações essenciais sobre as características físicas do meio e distribuição dos contaminantes neste. Dessa forma, sugere-se a caracterização em alta-resolução das porções mais impactadas da área de estudo, permitindo um aprimoramento do modelo conceitual da área e a otimização dos processos de remediação utilizados. / [en] Contaminated sites are those in which chemical substances that are potentially harmful to humans or the environment are present in higher concentrations than human established limits or their naturally occurring amounts (Resolução CONAMA number 420, 2009). Issues related to contaminated areas are deeply related to the fast-growing population on urban centers and the historical expansion of industrial and commercial activities near those (Sánchez, 2004). The importance of managing contaminated sites became clear after events such as the Love Canal disaster exposed how damaging they could be if left unattended, causing huge, permanent impacts both on human health and the environment (IPT, 2004). The vast array of chemicals used in the many existing industrial, commercial and agricultural activities include many potential contaminants of different physical and chemical nature. One distinct group of contaminants of particular interest are the NAPL (non-aqueous phase liquids), which include substances that when in direct contact with water form a distinct, immiscible phase. Two NAPL subcategories also exist based on their density relatively to water s: LNAPLs (light non-aqueous phase liquids), for those whose density is lower than water s, and DNAPLs (dense non-aqueous phase liquids), for those whose density is higher than water s. Since contaminants are mostly released near surface levels and migrate downwards due to gravity, their density is of great importance since it dictates their behavior when in contact with groundwater. NAPLs can be present in the environment in different physical forms, called phases (Huling and Weaver, 1991). These substances can dynamically change between phases depending on chemical and physical conditions, making them potential sources of long-term contamination if not correctly addressed (ITRC, 2009a). DNAPLs demand particular attention since they are capable of penetrating further downward after contacting capillary zones and the water table, and will only stop vertical movement when it encounters a material with low enough permeability to block it or it reaches residual saturation levels. This behavior often generates really complex contaminant distribution patterns that are exceptionally hard to map or predict, making targeting them with investigation or remedial actions a difficult task. Identifying and analyzing a potentially contaminated area usually relies on three main investigation steps: the preliminary, confirmatory and detailed investigations. Each step focuses on obtaining information from distinct sources and of different detail levels. The preliminary investigation focuses on gathering all existing information about a given area, including historical data about previous activities developed on or near it. The confirmatory step takes place if the preliminary analysis suggests that contamination may have happened, and focuses on obtaining more specific signs of it, such as altered fauna or flora, unusual smells and leakage of liquids or gases. This step may already employ basic investigation and analytical tools to gather and analyze samples. Then, if contamination is confirmed, the detailed investigation takes place in order to obtain specific data about physical properties of the affected area and chemical profiles of the contaminants. This step usually employs a variety of tools and techniques to allow collection of samples on the subsurface, as well as modelling the results in maps and 3D schemes. All the information obtained throughout the investigation steps is used to construct what is called a conceptual site model (CSM). The CSM is a collection of data about a given site, organized in ways that help responsible parties to identify meaningful information about present contaminants and their distribution, the lateral and vertical extent of the affected area, possible pathways to human or animal exposure, underground water flow rates, and many other parameters and pieces of information that may be valuable when it comes to making decisions about the site. The CSM is the primary tool used by decision makers to support their actions. Building a CSM relies heavily on data collected by different investigation techniques, the most traditional ones being soil sampling and the installation of aquifer monitoring wells. A wide array of high-resolution site characterization (HRSC) techniques has been developed throughout the years in order to allow a more precise definition of parameters, thus helping the CSM be as representative as possible of the actual conditions of a site. It is known that traditional techniques do not offer the necessary means to obtain high levels of detail when gathering data. This, paired with the acknowledgment that contaminated media are mostly heterogeneous by nature, made it even clearer that multiple techniques should be employed and their data used collaboratively for successfully approaching contaminated sites (Ryis, 2012; Suthersan, 2015; Derrite, 2017; Milani, 2017). In many countries, high-resolution techniques have been used widely in many projects for years now, with proven ability to provide higher levels of detail that is essential to complement traditional techniques. The increased usage of these tools is seen as a cooperative effort between private contractors and public entities and agencies (EPA, 2003b). The development of clear guidelines and legal frameworks are necessary when it comes to shifting from traditional investigation methods to newer, higher-resolution ones. Even whole methodologies such as the Triad have emerged as a much more efficient way of addressing contaminated sites, given that responsible parties have the adequate training and tools available. Triad requires an extensive planning phase in order to identify key decision-making points and possible setbacks during the whole project. It also relies on the usage of HRSC techniques that allow real-time data managing in order to make investigation campaigns as efficient as possible, both cost- and time-wise. In Brazil, there is still a lot of ground to cover in this matter. Only by 2009 the federal government issued a resolution including basic guidelines and goals for regional agencies for dealing with contaminated areas. Some local agencies, though, such as the Companhia Ambiental do Estado de São Paulo (CETESB), have been developing technical guidelines and legal framework for contaminated areas since the 1990s. A survey undertaken in 2015 with data gathered from local environmental agencies of each one of the 26 brazilian states showed that most of them were still non-compliant to basic steps such as the creation of contaminated site registries. By 2017, only São Paulo state officially recognized and suggested the use of HRSC in cases with complexities related to the contaminants or physical media. Low levels of demand from local environmental agencies together with scarce technical guidelines and scientific publications ends up limiting the rate at which HRSC is implemented throughout the country. The result is that many complex sites are still mainly addressed by traditional investigation and remediation techniques, leading to long and costly remediation projects that often struggle or fail to meet their goals (IPT, 2014). This study s goal is to present an overview of the management process of a contaminated site in Resende, a small city in Rio de Janeiro state, Brazil, which has been under intervention for over 10 years now and is still facing difficulties to meet its cleanup goals. The site has complexities associated with both the porous media and contaminants present, and yet hasn t employed any HRSC technique to help refine its original conceptual model. Questions are raised about whether the struggle to meet the established goals is possibly related to a poorly detailed CSM that may need further refinement.