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61.
Non-point source water pollution is a major problem in most parts of the world, but is also very difficult to quantify and control since it is not easily separated from point sources and can theoretically originate from the whole watershed. In this article, we evaluate the relationship between land use and land cover and four water pollution parameters in a watershed in Southeast Brazil. The four parameters are nitrate, total ammonia nitrogen, total phosphorous, and dissolved oxygen. To help concentrate on non-point source pollution, only data from the wet seasons of the time period (2001–2013) were analysed, based on the fact that precipitation causes runoff which is the main cause of diffuse pollution. The parameters measured were transformed into loads, which were in turn associated with an exclusive contribution area, so that every measuring station could be considered independent. Analyses were also performed on riparian zones of different widths to verify if the effect of the land cover on the water quality of the stream decreases with the increased distance. Pearson correlation coefficients indicate that urban areas and agriculture/pasture tend to worsen water quality (source). Conversely, forest and riparian areas have a reducing effect on pollution (sink). The best results were obtained for total ammonia nitrogen and dissolved oxygen using the whole exclusive contribution areas with determination coefficients better than R2≈0.8. Nitrate and total phosphorous did not produce valid models. We suspect that the transformation delay from total ammonia nitrogen to nitrate might be an important factor for the poor result for this parameter. For phosphorous, we think that the phosphorous sink in the bottom sediment might be the most limiting factor explaining the failure of our models.  相似文献   
62.
This paper investigates coping and adaptation strategies and institutional perceptions of hydrological risk at the local scale in Santarém, an Amazonian city in the state of Pará, Brazil. Methods and tools of analysis encompassed secondary data, field observations, and qualitative techniques (focus-group discussions and in-depth interviews). Stakeholders from affected neighbourhoods describe their means of coping with and adapting to flooding, focusing on purposefulness, type of initiative and investment, risk timing, temporal and spatial scope, and performance. The results comprise an inventory of 16 mostly structural measures. The perceptions of six institutions of general responses to flooding are presented as opinions on actions that reduce the effects of such events, individual strategies and collective community endeavours in at-risk areas, and the activities of the public and private sectors to manage floods. Understanding of coping and adaptation strategies and knowledge of institutional flood risk perceptions can benefit the implementation of risk and disaster reduction policies and practices.  相似文献   
63.
The Coastwatch (CW) project is aimed at monitoring the coastline with the involvement of volunteers. Between 2003 and 2007 a beach profiling method was informally proposed to CW participants in Portugal as an extra activity to include in the surveys. Beach profiling contributes to a better understanding of coastal processes by providing quantitative information on the spatial/temporal evolution of beaches, which is crucial for coastal management. The profiling method proposed to the CW project is based on the physical principle of communicating vessels, and only requires a simple and inexpensive homemade ??profiler??. The simplicity of putting together and using the profiler, added to the arithmetic straightforwardness of data analysis, makes this method adequate for several kinds of users and for most levels of education. Eight workshops were held that included a classroom explanation of the method, the construction of a profiler, the actual profiling of a beach, and a final classroom session of data processing and graphing. About 140 participants received such training, and several among them independently undertook beach profiling. Surveyed participants found the workshop and the beach profiling method interesting and useful, and considered it a valuable tool for teaching and for management. External stakeholders (coastal managers) highlighted the importance of beach profiling data for management decisions and considered that this method produces robust data, even when carried out by volunteers. Further advantages of the application of the method, in the context of coastal management initiatives, for scientists, managers, and volunteers are discussed.  相似文献   
64.
Flow regulation causes various environmental impacts in the downstream reaches of impounded rivers. The S?o Francisco River (SF) basin is Brazil’s third most important watershed. Several dams have been built in its course in the last four decades, mostly for flow regulation and hydropower generation. This paper presents an evaluation of historical changes in the flood regime. Three regions of the SF River basin, which are under the influence of different levels of regulation, were studied: the lower, middle, and upper SF River. The components of magnitude, frequency, and duration of floods were quantified for each region from 1940 to 1960 (prior to the construction of the first dam) and from 1986 to 2006 (after the last dam). The results have shown the inexistence of big floods in the downstream areas, decreasing durations of small floods as well as significant changes in the annual seasonality of floods. Reductions in the flood frequency were verified in all stretches, even in non-regulated systems, such as the lower Velhas River. The climate variation, which occurred in both period, was not able to explain the changes in the flood regime of S?o Francisco River; therefore, dams and other anthropogenic activity are the main factors promoting the temporal variability of streamflows in the S?o Francisco basin.  相似文献   
65.
66.
This paper discusses the recent retreat of glaciers and the changes in supraglacial lakes in the Bhutan Himalaya during the last two decades. We calculated the changes in clean and debris-covered glaciers and the formation, disappearance, and expansion of glacial lakes during the beginning of 1990s, 2000s, and 2010 using Landsat TM and ETM+ images. For this purpose, eight river sub-basins namely Wang Chu, Chamkar Chu, Dangme Chu, Kuri Chu, Mangde Chu, Mo Chu, Pho Chu and Northern Basin were considered. A retreating trend was found in the case of clean glaciers. Debris-covered glaciers in this region were found to have undergone an increase of about 29 %, and this increase was partially contributed by those expanded upstream. This increase in the debris-covered area is higher on the southern side of the Bhutan Himalaya. It is found that a number of moraine-dammed glacial lakes were formed during this period and can be potentially dangerous depending on the size, distance from the glacier and altitude. Most of the glacial lake formation and expansion occurred on the southern side of the Bhutan Himalaya.  相似文献   
67.
In this paper we analyse how risk factors in highly industrialised agriculture are connected to animal neglect. With Danish agriculture as a case study, we use two types of data. First, we use register data from Statistics Denmark to map how risk factors such as farmers’ financial and social troubles are connected to convictions of neglect. Second, we analyse narratives where interviewed farmers, involved in cases of neglect, describe how they themselves experienced the incidents. We find that while livestock farmers in general have a low risk of animal neglect problems, a small percentage of them face severe financial difficulties, divorce and psychiatric problems, which are connected to an increased risk of being convicted for the neglect of farm animals. The narratives bring forward themes of pressure related to financial trouble, technological break down, family problems, stress and a growing concern among the farmers towards the governmental control in farm animal production. We discuss how these factors can be used to identify and help farmers with a high risk of being convicted of livestock neglect.  相似文献   
68.
Understanding the evolutionary processes from recent demographic history is especially difficult for interstitial organisms due to their poorly known natural history. In this study, the genetic variation and population history of the four Ototyphlonemertes (Diesing in Sitz ber Math Nat Kl Akad Wiss Wien 46:413–416, 1863) species were evaluated from samples collected along the Brazilian coast (between 27°31′S and 13°00′W) in 2006. The mitochondrial region cytochrome c oxidase subunit 3 (COX3) is analyzed to assess the genetic variation of these dioecious species. Although these species have a sympatric distribution along the coast, our data suggest that their levels of differentiation and their demographic histories differ sharply. There is strong evidence of gene flow among demes in O. erneba and O. evelinae, and their level of structuring is much lower than for the other two species. Indeed, the COX3 fragment reveals cryptic lineages in O. lactea and O. parmula. The results seem to contradict the high genetic structuring and low intrapopulational variability expected with the ecological constriction and habitat discontinuity faced by these organisms, meaning that there might be gene flow among populations or their dispersal capability has been underestimated.  相似文献   
69.
Environmental Science and Pollution Research - As well as a lead-related environmental factor, genetic factors could also corroborate important changes in intelligence quotient (IQ) through...  相似文献   
70.
The increase in energy demand due to economic and population growth necessitates the expansion of the Brazilian energy supply. Hydropower energy, a renewable energy source, arguably clean, presents an energy solution for many countries such as Brazil, with large hydric reservoirs, which help them reduce energy dependence on fossil and imported fuel sources. However, it must be emphasized that without careful planning, the creation of hydropower plants will cause severe social and environmental damage due to the large areas that need to be flooded for the implementation of these plants. The installation of hydropower plants floods vast forest areas, causing loss of biodiversity, displacement of native Brazilian people and riverside populations, and changes to the water acid levels and the natural course of rivers. To mitigate these effects, authorities must first conduct a study on installation possibilities and potential socio‐environmental consequences, to be interpreted and used by the agents involved. Aiming to analyze the social‐environmental impacts of the hydropower plants, this research seeks to investigate the capacity of mitigation of the negative effects of the implementation of the hydropower plants, specifically with regard to the Belo Monte plant, Brazil.  相似文献   
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