No abstract

Freshwater resources are increasingly scarce due to human activities, and the understanding of water quality variations at different spatial and temporal scales is necessary for adequate management. Here, we analyze the hypotheses that (1) the presence of a wastewater treatment plant (WWTP) and (2) a polluted tributary that drains downstream from the WWTP change the spatial patterns of physicochemical variables (pH, turbidity, dissolved oxygen, and electrical conductivity) and nutrient concentrations (reactive soluble phosphorus, total phosphorus, nitrogen series, total nitrogen, and total dissolved carbon) along a mid-order river in SE Brazil and that these effects depend on rainfall regime. Six study sites were sampled along almost 4 years to evaluate the impacts of human activities, including sites upstream (1-3) and downstream (5-6) from the WWTP. The impacts were observed presenting an increasing trend from the source (site 1) towards Água Quente stream (site 4, the polluted tributary), with signs of attenuation at site 5 (downstream from both WWTP and site 4) and the river mouth (site 6). Input of nutrients by rural and urban runoff was observed mainly at sites 2 and 3, respectively. At sites 4 and 5, the inputs of both untreated and treated wastewaters increased nutrient concentrations and changed physicochemical variables, with significant impacts to Monjolinho River. Seasonal variations in the measured values were also observed, in agreement with the pluviometric indexes of the region. Univariate analyses suggested no effect of the WWTP for most variables, with continued impacts at sites downstream, but non-parametric multivariate analysis indicated that these sites were recovering to chemical characteristics similar to upstream sites, apparently due to autodepuration. Therefore, multivariate methods that allow rigorous tests of multifactor hypotheses can greatly contribute to determine effects of both point and non-point sources in river systems, thus contributing to freshwater monitoring and management.

No abstract

No abstract

O objetivo do presente ensaio conceitual é propor reflexões sobre a efetividade da participação dos representantes nos Comitês de Bacias Hidrográficas e questões relativas à representação e representatividade no processo de tomada de decisão sobre a gestão de Bacias Hidrográficas. Comitês de Bacia Hidrográfica são espaços que promovem a gestão participativa dos recursos hídricos. Nesses espaços estão representantes do poder público, da sociedade civil e de usuários de água. Contudo, infere-se que a efetividade e a qualidade da representação exercida pelos representantes estão comprometidas, em razão de diversos motivos. A pesquisa pautou-se na revisão da literatura sobre a temática e na análise de distintas configurações de participação social. Foi possível identificar que os Comitês de Bacia são espaços legítimos de participação, e que a qualidade da representação envolve fatores referentes à atuação dos representantes nesses colegiados, como: atuação cidadã, consciência individual sobre o espaço coletivo e compartilhamento de interesses.