CAGNON, F. A.-D¡ssertaçao de lvlesìrado, 2OOc Tabela 6.1-Perceniuais de erros abaixo de 10% e média das condutividades elétricas para cada campanharesultados obtidos em laboratório e no campo Tabela 6.2-Sumário dos Parâmetros Hidrogeológicos para o Aqüífero Adamantina LISTA DE SUADROS LISTA ÞH TABELAS Quadro 3.1-Relaçáo entre as espécies de nitrogênio e seus respectivos estados de oxidação (STUMM & MORGAN,1996). Quadro 4.1-Populaçáo de Urânia desde 1970 a 2000 e projeção para 2010 Quadro 5.1-Faixas de leitura dos parâmetros medidos com ReFLËX-plus Quadro 5.2-Programa de amostragem das águas subterrâneas Quadro 5.3-Relaçáo dos parâmetros analisados em laboratór¡o e respectivos métodos analíticos Quadro 5.4timites de detecção obtidos para cada parâmetros Quadro 5.5-Sumário dos dados utilizados na confecçáo dos diagramas Quadro 6.1-Cadastro das fontes potenciais cle contam¡naçáo-fossas Quadro 6.2-Cadasiro das fontes potenciais de contaminaçãoárea agrícola 61

This study follows the geochemistry of nitrogen in a Cretaceous and unconfined sedimentary aquifer in the city of Urânia (Brazil) over 20 years. Although the sewer network was built in the 1970s, the nitrate contamination problem (>45 mg/L-NO3−) persists to this day. The oldest urbanization areas located in the north of the city initially used cesspits for wastewater and currently present the highest nitrate concentrations (>120 mg/L-NO3−), with the plume reaching the deeper aquifer portions (up to 100 m). The contamination is not as dramatic in the south part of the city, where urbanization including installation of the sewage network with PVC pipes that are more resistant to leak than the old ceramic networks occurred after 1985. Based on the constructive well profiles, three hydrogeochemical zones were established: shallow (<20 m deep), with average nitrate of 63 mg/L-NO3−; intermediate (20–60 m), with 30 mg/L-NO3−; and deep (>60 m), with 17 mg/L-NO3−. The current total nitrate mass in the aquifer exceeds 731 kg-NO3−. Numerical flow (Modflow) and transport (MT3D) model scenarios support the hypothesis that the nitrate contamination is caused by substantial infiltration of nitrogen through the cesspits until the 1970s, but after the 1990s, leaks from the sewer network should be responsible for the maintenance of the recently observed high concentrations of nitrate.

The investigation of contaminated areas in fractured aquifers represents a great technical challenge, due to the frequent conditions of heterogeneity and anisotropy of these environments, which often make it difficult to identify and predict pathways of subsurface contamination. This work aims to contribute to the development of this subject, through the presentation of the results of an investigation in which geophysical logging tools and straddle packers were used, which allowed the development of a more suitable hydrogeological conceptual model of the study area. Two boreholes were drilled and geophysical logging (gamma, caliper and high resolution acoustic televiewer) were used for the geological-structural characterization of the aquifer. Heatpulse flowmeter and straddle packers were then used to obtain data on hydraulic potentials and flows and for the collection of discrete water samples for chemical analysis. Two types of gneiss rocks were identified below the weathering zone (thickness >30 m), one with predominance of mafic bands, more weathered and with a higher fracture density, up to 65 m, and another deeper one, with the predominance of felsic bands. Seven groups of fractures were defined, being those of Group 1, with low dip angles, the most frequent and important for flow until 65 m, and Group 2 (N to NE-SW with high dips to W and NW) more frequent in deeper felsic gneisses. Downward hydraulic potentials were identified down to 65 m and upward potentials from the bottom up to 65 m. A hydraulic test allowed identifying the occurrence of hydraulic connection between the shallow weathering zone and the underlying fractured aquifer.

O objetivo deste trabalho é propor um método de gerenciamento ambiental de obras lineares, tal como ferrovias de alta velocidade, nos trechos em que o traçado intercepta áreas contaminadas (AC), potencialmente contaminadas (AP) ou suspeitas de contaminação (AS). O estudo de caso utilizou o método proposto durante avaliação ambiental preliminar para a futura implantação do trem de alta velocidade entre Rio de Janeiro e Campinas (TAV). O método consiste na execução das seguintes etapas de trabalho: (a) identificação e caracterização de AP, AC e AS ao longo do traçado; (b) classificação dos trechos de obra; (c) elaboração de modelos conceituais de contaminação; (d) identificação de cenários e respectivas implicações ambientais sobre as obras e (e) proposição de ações ambientais. As ações de gerenciamento ambiental propostas para a fase de obras tiveram como objetivos minimizar impactos ambientais e possibilitar a implementação da obra com segurança para os trabalhadores no que diz respeito ao tema "áreas contaminadas". Adicionalmente, a estratégia proposta deverá contribuir para evitar eventuais atrasos na emissão de licenças ambientais e aumento nos custos do empreendimento

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