A B S T R A C TPlant cover plays an essential role in the maintenance and balance of the hydrological cycle, performing functions in the control of water availability, which guarantee flow permanence. The use of mathematical models is an alternative to represent the hydrological system and help in the understanding of phenomena involving the variables of the water cycle, in order to anticipate and predict impacts from potential changes in land use. In the present study, the hydrological model SWAT (Soil and Water Assessment Tool) was used to analyse the dynamics of flow and water flow in the Pará River Basin, Minas Gerais, Brazil, aiming to evaluate the impact caused by changes in land use in water availability. The adjusted model was assessed by the coefficient of efficiency of Nash-Sutcliffe (between -0.057 to -0.059), indicating high correlation and coefficient of residual mass (0.757 to 0.793) and therefore a satisfactory fit. An increase of about 10% in the basin flow was estimated, as a function of changes in land use, when simulating the removal of the original 'Cerrado' vegetation and of the seasonal semideciduous forest for pasture implementation in 38% of the basin.Impacto de alterações no uso do solo na vazão da Bacia do Rio Pará, MG R E S U M OA cobertura vegetal exerce papel fundamental na manutenção e no equilíbrio do ciclo hidrológico, desempenhando funções no controle da produção de água que garantem a permanência de vazões. O uso de modelos matemáticos é uma alternativa para representar o sistema hidrológico e auxiliar na compreensão dos fenômenos que envolvem as variáveis do ciclo da água para antecipar impactos decorrentes de eventuais mudanças no uso da terra. Neste trabalho é utilizado o modelo hidrológico SWAT (Soil and Water Assessment Tool) para analisar a dinâmica da vazão na bacia do Rio Pará, em Minas Gerais, Brasil, com o objetivo de avaliar o impacto provocado pelas alterações de uso do solo na disponibilidade de água da bacia do Rio Pará. O ajuste do modelo foi avaliado pelo coeficiente de eficiência de Nash-Sutcliffe (entre -0,057 a -0,059) indicando alta correlação e coeficiente de massa residual (0,757 a 0,793) e, portanto, um ajuste satisfatório. Estima-se que houve incremento de cerca de 10% na vazão da bacia em função das alterações no uso do solo, contemplando basicamente a supressão da vegetação original de Cerrado e de Floresta Estacional Semidecidual para implantação de pastagem em 38% do território da bacia.

IntroductionGenotoxic biomarkers have been studied largely in adult population, but few studies so far have investigated them in children exposed to air pollution. Children are a high-risk group as regards the health effects of air pollution and some studies suggest that early exposure during childhood can play an important role in the development of chronic diseases in adulthood. The objective of the project is to evaluate the associations between the concentration of urban air pollutants and biomarkers of early biological effect in children, and to propose a model for estimating the global risk of early biological effects due to air pollutants and other factors in children.Methods and analysisTwo biomarkers of early biological effects, DNA damage by the comet assay and the micronuclei (MN) test, will be investigated in oral mucosa cells of 6–8-year-old children. Concurrently, some toxic airborne pollutants (polycyclic aromatic hydrocarbon (PAH) and nitro-PAH) and in vitro air mutagenicity and toxicity in ultra-fine air particulates (PM0.5) will be evaluated. Furthermore, demographic and socioeconomic variables, other sources of exposures to air pollutants and lifestyle variables will be assessed by a structured questionnaire. The associations between sociodemographic, environmental and other exposure variables and biomarkers of early biological effect using univariate and multivariate models will be analysed. A tentative model for calculating the global absolute risk of having early biological effects caused by air pollution and other variables will be proposed.Ethics and disseminationThe project has been approved by the Ethics Committees of the local Health Authorities. The results will be communicated to local Public Health Agencies, for supporting educational programmes and health policy strategies. LIFE+2012 Environment Policy and Governance. LIFE12 ENV/IT/000614.

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Artigo recebido para publicação em 07/04/2011 e aceito para publicação em 02/08/2011. RESUMO:A

Planted forests have been increasingly highlighted in the Brazilian scenario, maintaining status regarding their environmental effects, among them those related with soils. The objectives of this work were to evaluate and to compare the physical attributes of a typic distroferric Red Latosol under Eucalyptus cloeziana, E. grandis, E. Pilularis and Corymbia maculata coverage, 37 years after being planted at the Federal University of Lavras campus. The soil profiles were sampled down to 1 m depth in order to analyze their particle-size distribution, porosity, structure and water retention. The results were submitted to analysis of variance, Scott-Knott multiple means comparison test, correlations and linear regression. The profiles presented appropriated soil physical conditions to provide good plant development. The bulk density and microporosity increased in depth while the total pore volume, macroporosity and aggregates stability decreased in depth. The soil profiles under E. cloeziana and C. maculata coverage presented lower density, more pores, are more structured, present lower water retention capability and lower water availability than the soil profiles under E. grandis and E. pilularis.Index terms: Soil porosity, soil structure, water retention in soil. RESUMOAs florestas plantadas ocupam destaque crescente no cenário nacional, permanecendo a questão sobre os seus efeitos ambientais, dentre eles àqueles relacionados ao solo. No presente trabalho, objetivou-se avaliar e comparar atributos físicos de Latossolo Vermelho distroférrico típico sob cobertura de Eucalyptus cloeziana, E. grandis, E. Pilularis e Corymbia maculata, 37 anos após plantio, no campus da Universidade Federal de Lavras. Os perfis foram amostrados até um metro de profundidade, sendo analisadas textura, porosidade, estrutura e retenção de água. Os resultados foram submetidos a análises de variância, testes de comparação múltipla de médias Scott-Knott, correlação e regressão linear. Os perfis apresentaram condições físicas consideradas adequadas ao bom crescimento das plantas. A densidade e a microporosidade aumentaram em profundidade; o volume total de poros, macroporosidade e a estabilidade de agregados decresceram no perfil. Os perfis sob E. cloeziana e C. maculata apresentaram-se menos densos, mais porosos e estruturados, e com menor capacidade de retenção e disponibilidade de água em relação aos perfis sob E. grandis e E. pilularis. Termos para indexação:Porosidade do solo, estrutura do solo, retenção de água no solo.