Thiago Lucon

The Sociedade Excursionista e Espeleológica has done since 2005 work of prospecting, mapping and characterization of karst in the region of Serra do Iuiú-Iuiú-BA. The regions presents outcrop of carbonatic rocks that are more susceptible to dissolution and because of this provide an environment conducive to the formation of caves. This work presents in a summarized way the results the three stages of field made during the periods from 01/20-30/2005, 09/10-21/2007 and 01/12-28/2009. The results of a preliminary point to the emergence of a new speleological district.

The object of this paper is to increase the biological knowledge throught a macro-caracterization of the exokarstic sites, performed by a fast ecological valuation of the biota, including fauna and flora individuals ocurring in the region. The expedition happened between 13 and 24 ...

The intense population growth in the city of Ouro Preto, along with the lack of effective environmental policies, brings several consequences for its inhabitants. In an attempt to reverse this situation or, at least minimize these effects, urban environmentalists have developed several tools and strategies to help in the decision-making process of the planning of urban cities, such as the Percentage of Green Areas (PGA) and the Green Area Index (GAI), among others. This study calculated the Population Density (PD), PGA and GAI in the city of Ouro Preto based on IBGE censused from 2007, obtaining the following results: from 27.9 km 2 of urban perimeter, approximately 24% (6.69 km 2) consists of built-up areas, and 76% (21.09 km 2) of green areas. The study shows that the most populous neighborhoods are Padre Faria, Morro Santana, Morro São João, Nossa Senhora das Dores and Vila Aparecida. The areas with higher PD belong to the neighborhoods Vila Itacolomi, Alto da Cruz and São Cristo...

Grande parte da agua consumida pela humanidade e oriunda de reservas subterrâneas e, devido a ocupacao do solo sem planejamento, o risco de contaminacao de aquiferos pode gerar problemas no desenvolvimento economico e social de uma regiao. Estudos que visam a caracterizacao de areas vulneraveis a contaminacao de aquiferos podem auxiliar nesse planejamento do controle da qualidade da agua. Consequentemente, uma validacao do mapa e favoravel para sua confiabilidade. Nesse contexto, a pesquisa buscou validar o mapa de vulnerabilidade intrinseca da bacia do rio Sao Miguel (≈ 520 km²) por meio de estudos utilizando o mapeamento hidroquimico com os teores anomalos de nitrato acima dos valores permitidos pela Resolucao do CONAMA no 396. A bacia esta localizada no centro oeste de Minas Gerais, inserida no extremo meridional da bacia do rio Sao Francisco, com presenca de rochas carbonaticas neoproterozoicas do Grupo Bambui, pertencentes a Formacao Sete Lagoas. O metodo de vulnerabilidade EPI...

A pesquisa buscou analisar as concentracoes quimicas do elemento cadmio (Cd) das aguas subterrâneas da bacia do rio Sao Miguel, utilizando-se do mapeamento hidroquimico, visando o melhor conhecimento sobre a qualidade dessas aguas perante padroes estabelecidos pelas legislacoes vigentes, alem de verificar a influencia da sazonalidade e propor valores de background para este elemento. A bacia esta localizada no centro oeste de Minas Gerais, extremo meridional da bacia do rio Sao Francisco, inserida na Provincia Carstica de Arcos Pains, representada principalmente por rochas carbonaticas e peliticas da Formacao Sete Lagoas (Grupo Bambui), com exposicoes secundarias do embasamento granito-gnaissico pertencentes ao Complexo Campo Belo. A partir das analises quimicas, realizou-se um tratamento de dados pelo Microsoft Excel®, onde foram gerados graficos para uma melhor interpretacao dos resultados. Com o intuito de melhorar a visualizacao dos resultados, as concentracoes de Cd foram inser...

Valores de Fundo Natural, ou Natural Backgroung Levels (NBL) representam a faixa natural de concentracoes de um parâmetro hidroquimico. Caso se tenha uma amostra com concentracao acima do NBL, tem-se um indicativo de intervencao antropogenica ou de uma anomalia geogenica. A regiao investigada engloba a Area de Protecao Ambiental (APA) Carste Lagoa Santa, Minas Gerais. O NBL foi calculado para sete parâmetros, e o Nitrato e Solidos Totais Dissolvidos foram eleitos para exemplificacao. Foi feita a analise hidroquimica em 69 pocos perfurados no sistema aquifero carstico, 3 nos pelitos da Formacao Serra de Santa Helena e 7 no Complexo granito-gnaissico. Para calculo do NBL, determinou-se a melhor distribuicao estatistica para cada parâmetro por meio da ferramenta Individual Distribution Identification do software Minitab 17®. Em seguida, plotaram-se graficos de probabilidade, sendo o NBL o valor referente ao 90o percentil da distribuicao estatistica. Os resultados numericos foram entao ...

The intense population growth in the city of Ouro Preto, along with the lack of effective environmental policies, brings several consequences for its inhabitants. In an attempt to reverse this situation or, at least minimize these effects, urban environmentalists have developed several tools and strategies to help in the decision-making process of the planning of urban cities, such as the Percentage of Green Areas (PGA) and the Green Area Index (GAI), among others. This study calculated the Population Density (PD), PGA and GAI in the city of Ouro Preto based on IBGE censused from 2007, obtaining the following results: from 27.9 km2 of urban perimeter, approximately 24% (6.69 km2) consists of built-up areas, and 76% (21.09 km2) of green areas. The study shows that the most populous neighborhoods are Padre Faria, Morro Santana, Morro Sao Joao, Nossa Senhora das Dores and Vila Aparecida. The areas with higher PD belong to the neighborhoods Vila Itacolomi, Alto da Cruz and Sao Cristovao...

The contamination of karst aquifers by anthropogenic activities causes a major issue regarding environmental policies, since they present high sensitivity, influenced by unique features such as dolines, swallow holes, and conduits. This paper is focused on the Carste Lagoa Santa Protection Unit, MG, Brazil, and presents three main objectives: to determine the natural background levels of chloride, nitrate, sulfate, and phosphate; to indicate the locations where the concentrations of those parameters exceed the natural background levels in the existing vulnerability map and, finally, to determine the proportion of the areas (in percentage) where this surpassing occurs, according to the vulnerability classes (high, moderate and low). Results have shown values (90th percentile) of 2.4 mg/L, 1.0 mg/L, 5.3 mg/L, and 0.1 mg/L, for Cl−, NO3−, SO4−2, and PO4−3, respectively, indicating that for all four parameters, there were areas (mainly distributed within moderate vulnerability portions) where the values were surpassed, which suggests anthropogenic activity due to the presence of urban settlements and agricultural activities. Therefore, the proposal of natural background levels was essential to understand the hydrochemistry of the studied region.

Resumo:A área em estudo contempla a bacia do rio São Miguel (≈520 km2), afluente do rio São Francisco, situada na província cárstica de Arcos-Pains e inserida na Bacia Hidrográfica do Alto São Francisco (235.635 km2). Com o objetivo de avaliar preliminarmente a utilização do mapeamento hidroquímico para verificar espacialmente a qualidade das águas superficiais, foram realizadas análises hidroquímicas em 34 pontos da bacia em apreço durante uma estação seca e uma chuvosa. As análises incluíram a determinação de parâmetros físico-químicos (temperatura, pH, Eh, CE, STD, oxigênio dissolvido e turbidez), assim como a concentração de ânions (NO3-, PO43-, HCO3-, SO42- e Cl-), cátions maiores e elementos traço. Os dados foram tratados e comparados com os valores estabelecidos pela legislação Conama nº 357 (2005) para aguas da classe 1 os quais balizaram os valores plotados nos mapas hidroquímicos, facilitando, desta maneira, a visualização dos locais que violaram o limite. Foram observados...

Abstract Karst aquifers are, besides important strategic reservoirs of good quality water, heterogeneous and anisotropic, where highly permeable karst networks result in insufficient time for contaminant degradations, and hence the quasi-immediate contamination of the aquifer. The EPIK method is a low-cost technique and was developed to map karst regions based on four main feature indexes: 1) epikarst; 2) protective cover; 3) infiltration conditions; and 4) karst network development. However, the method was developed according to European hydrogeologic and temperate climatic contexts, where its application without adaptations in regions in different contexts may result in possible misunderstandings, such as overlook, underestimate or overestimate significances of some parameters (e.g. soil covers, rainfall regimes, morphological domains). The Brazilian Sao Miguel watershed, a tropical karst region where the city of Pains is located (southwestern Minas Gerais), is characterized by high levels of thermotolerant coliforms, phosphorus, nitrate, and cadmium in surface water and groundwater. These contaminants come from, agriculture, livestock, and urban areas. Due to these issues and to provide a tool of water resource management and land use planning, the EPIK method was adapted to the hydrogeologic reality of the Sao Miguel watershed, considering both local vegetation and the current Brazilian speleological heritage protection legislation. Results revealed that 52% of the area has moderate vulnerability and 7% high vulnerability, this latter one concentrated in areas close to mining activities and urban areas. The study provided a reliable map and adapted technique which can be used in other Brazilian karst regions and other tropical karst regions.