RESUMOPalavras-chave: balanço hidrológico -água subterrânea -recurso

The present paper examines the relationship between hydrochemical characteristics and endemic dental fluorosis, controlling for variables with information on an individual level. An epidemiological survey was carried out in seven rural communities in two municipalities in the state of Minas Gerais, Brazil. The Thystrup & Fejerskov index was employed by a single examiner for the diagnosis of dental fluorosis. A sampling campaign of deep groundwater in the rural communities of interest was carried out concomitantly to the epidemiological survey for the determination of physiochemical parameters. Multilevel modeling of 276 individuals from seven rural communities was achieved using the non-linear logit link function. Parameters were estimated using the restricted maximum likelihood method. Analysis was carried out considering two response variables: presence (TF 1 to 9) or absence (TF = 0) of any degree of dental fluorosis; and presence (TF ≥ 5—with loss of enamel structure) or absence of severe dental fluorosis (TF ≤ 4—with no loss of enamel structure). Hydrogeological analyses revealed that dental fluorosis is influenced by the concentration of fluoride (OR = 2.59 CI95% 1.07–6.27; p = 0.073) and bicarbonate (OR = 1.02 CI95% 1.01–1.03; p = 0.060) in the water of deep wells. No other variable was associated with this prevalence (p > 0.05). More severe dental fluorosis (TF ≥ 5) was only associated with age group (p < 0.05). No other variable was associated to the severe dental fluorosis (p > 0.05). Dental fluorosis was found to be highly prevalent and severe. A chemical element besides fluoride was found to be associated (p > 0.05) to the prevalence of dental fluorosis, although this last finding should be interpreted with caution due to its p value.

Article available from www.scielo.br/rsp Beliefs and attitudes about endemic dental fluorosis among adolescents in rural BrazilCrenças e atitudes em relação à fluorose dentária de jovens em região rural do Brasil ABSTRACT OBJECTIVE: To understand beliefs and attitudes about fluorosis among young people living in a rural area. METHODOLOGICAL PROCEDURES:Qualitative study consisting of semistructured interviews with 23 adolescents with dental fluorosis, 14 teachers and three health authorities in the city of São Francisco, Southeastern Brazil, in 2002. Content analysis and social representation theory were applied. ANALYSIS OF RESULTS:The organoleptic characteristics of carbonates that affect groundwater (salty flavor, whitish coloration, and turbidity) associated with negative aspects of household use of this water are considered a cause of mottled enamel. Even after contact with researchers who investigated this phenomenon and helped find a solution for this condition, the local population is still unwilling to accept fluoride as the cause of the problem and does not fully agree to use water from other sources because they are afraid of the quality of water. CONCLUSIONS:Misperceptions of the causes of dental fluorosis and water treatment costs compromise the implementation of uncontaminated surface water supplies. Health education strategies are required in parallel with solutions for securing water supply in drought-ravaged areas. DESCRIPTORS: 262Endemic dental fluorosis in Brazil Castilho LS et al Fluoride is added to drinking water in low concentrations (0.7-1.2 mg/L in the US) to inhibit the occurrence and slow progression of dental caries. 13 However, chronic excessive exposure to high levels of fluorine can result in dental or skeletal fluorosis. In severe dental fluorosis, the tooth enamel becomes opaque, more porous and friable with a mottled appearance ranging from white to brown and black. There is loss of enamel substance and anatomic dental deformities may occur, at times evolving toward tooth loss. 4 In Brazil, severe forms of endemic dental fluorosis have been described in the states of São Paulo, Santa Catarina 3 and Minas Gerais. CONCLUSÕES:Percepções equivocadas em relação às causas da fluorose dentária e a dificuldade em custear o tratamento da água comprometem a implantação de suprimento de água de superfície não contaminada. Estratégias de educação em saúde devem ser implementadas paralelamente a soluções para captação de água de fontes alternativas não contaminadas em localidades afetadas pela seca.

No abstract

Using closed mines as natUral laboratories to teach geosciences: the examPle of diamantina (MG). The irresponsible closing of mining operations is a current topic of environmental and social concern, which has led to increased discussion of the "future uses of mined areas". In this paper, we present the great educational potential of some closed mines, proposing their use as natural laboratories to teach Geosciences. We use the example of Diamantina (MG), where long disabled old diamond mines are abundant. Inside the mines, it is quite common for dynamic sedimentary systems to develop, where several processes take place simultaneously. In these systems, it is possible to observe sedimentary processes and products in different environments and contexts, which provides an ideal situation for basic and advanced teaching of topics related to sedimentology, stratigraphy and geomorphology. The features that may be observed allow a thorough scalar analysis, as well as a discussion of differences and similarities with real-size sedimentary environments. In addition, the simultaneous occurrence of processes, products and ancient sedimentary structures provides an excellent opportunity to discuss the principle of Actualism. IntroduçãoQualquer processo de mineração, seja ele artesanal ou mecanizado, acarreta em alterações no meio físico que, dependendo de seu grau de importância, podem constituir impactos ambientais negativos. Este fato, inerente à atividade mineradora, é hoje levado em consideração pela legislação, que exige diversos níveis de licenciamento ambiental e também um detalhado planejamento do fechamento da lavra, de modo a garantir míni-mo impacto ambiental e posterior recuperação da área lavrada. Este cenário, entretanto, é recente, remontando apenas às últimas décadas.No Brasil, ao longo de séculos, diversas localidades surgiram e se desenvolveram em íntima ligação com a mineração. Em vários destes locais ainda são visíveis as cicatrizes de dezenas ou centenas de anos de explotação predatória e impensada, que hoje representam um passivo ambiental de proporções imensas. É o caso, por exemplo, das jazidas diamantíferas do sudeste brasileiro, descobertas entre os séculos XVIII e XIX e, desde então, continuamente lavradas por meio de garimpos artesanais e dragas mecanizadas. Na Chapada Diamantina (BA), Matta (2006) e Santos et al. (2010) diagnosticaram diversos impactos ambientais negativos relacionados à atividade garimpeira. Merecem destaque o assoreamento da rede hidrográfica, drenagem de aqüíferos e nascentes, perda de vegetação, processos erosivos acelerados e um grande impacto visual. Na região de Diamantina (MG) os mesmos processos são observados, associados às abundantes lavras de diamante abandonadas que ocorrem em seu entorno.Em virtude deste panorama, tem sido conside-

O VI Encontro do Fórum Nacional de Cursos de Geologia foi promovido entre os dias 30 de maio e 2 de junho de 2006, pelas seguintes universidades: Federal do Rio de Janeiro (UFRJ), Univ. Federal Rural do Rio de Janeiro (UFRRJ) e do Estado do Rio de Janeiro (UERJ) e pela Sociedade Brasileira de Geologia (SBGeo), nos institutos aos quais estão vinculados os cursos de Geologia das três instituições.

RESUMOAs rochas carbonáticas e pelíticas neoproterozóicas do Grupo Bambuí formam um sistema aquífero importante em Jaíba, Verdelândia e Varzelândia, região semiárida de Minas Gerais. Os autores têm realizado estudos geológicos e hidrogeológicos naqueles municípios para consolidar um modelo de funcionamento do aquífero que ofereça subsídios à implantação de uma rede de monitoramento eficiente da qualidade das águas subterrâneas e que contribua para o entendimento das ocorrências de altas concentrações naturais de fluoreto registradas na região. Os objetivos deste trabalho são identificar e caracterizar as unidades hidrogeológicas, por meio da pesquisa de campo e análise das características das captações por poços tubulares, e propor um modelo conceitual de circulação das águas subterrâneas com base no estudo de lineamentos, fraturas, feições cársticas, potenciometria e de isótopos de trítio natural nas águas subterrâneas. Os resultados evidenciam o controle estrutural nos fluxos subterrâneos raso e profundo, este de caráter regional, e a influência das formas de recarga e circulação das águas na produtividade dos poços, na salinização e nas ocorrências de concentrações elevadas de fluoreto.Palavras chave: aquífero cárstico-fissural, Grupo Bambuí, fluoreto na água subterrânea ABSTRACTThe neoprotherozoic limestones and siltstones of Bambui Group constitutes an important aquifer system in Jaiba, Verdelândia e Varzelândia, in the semi-arid region of Minas Gerais. The authors have realized geological and hydrogeological studies in those municipalities in order to consolidate an aquifer model that supports the construction of an efficient network to monitor the groundwater quality and helps to understand the occurrence of high concentrations of natural fluoride in groundwater in the region. This article aims to identify and characterize the hydrogeological units, with field research and analyses of boreholes characteristics, and propose a conceptual model of groundwater circulation, using the lineaments, fractures and karstification studies, potentiometric map, isotopic analysis (natural tritium) in groundwater samples. The results shows structural control on shallow and deep regional flows, and the influence of recharge types and water circulation on production of boreholes, salinity and the occurrence of high fluoride concentrations.

-