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亚马孙河流域汞的生物地球化学研究 被引量:2
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作者 julio cesar wasserman Sandra Hacon +1 位作者 MariaAngélicawasserman 菅小东 《AMBIO-人类环境杂志》 2003年第5期336-342,共7页
本文阐述和评论了影响亚马孙河流域汞循环的途径,并提出了新的研究方向。对于汞污染源的讨论,无论是天然的还是人为的,都缺乏基本的论据。毫无疑问,黄金矿山释放的汞已经局部地提高了环境中汞的浓度,但在整个亚马孙河流域,与一些学者在... 本文阐述和评论了影响亚马孙河流域汞循环的途径,并提出了新的研究方向。对于汞污染源的讨论,无论是天然的还是人为的,都缺乏基本的论据。毫无疑问,黄金矿山释放的汞已经局部地提高了环境中汞的浓度,但在整个亚马孙河流域,与一些学者在远离金矿的土壤中测出的高浓度数值相比,这种负荷并不显著。土壤中汞的高浓度现象有一个合理的解释,即B层(淀积层)是在地质时期蓄积了汞的'海绵体',当发生侵蚀和森林火灾时,汞又被释放回循环体系。源于人类活动导致的亚马孙河流域森林的环境退化,很可能会加速汞的释放。汞在还原性的缺氧环境——沉积物和水中——的转换也是理解汞的环境甲基化的一个关键性问题。在亚马孙河流域环境所做的这项研究非常有限,研究结果只能得出受限的结论,进一步的工作应注重结合时间和空间变化的监测计划。 展开更多
关键词 亚马孙河流域 汞循环 地球化学 生物化学 环境污染 污染源 环境甲基化
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Remote Sensing Applied to the Evaluation of Spatial and Temporal Variation of Water Quality in a Coastal Environment, Southeast Brazil
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作者 Pedro Bettencourt julio cesar wasserman +5 位作者 Fábio Ferreira Dias Paulo Roberto Alves Dandara Bernardino Bezerra Camila Américo Santos Luis Perez Zotes Sérgio Ricardo Barros 《Journal of Geographic Information System》 2019年第5期500-521,共22页
The monitoring of water quality in large coastal regions demands great analytical efforts through the collection of many samples, over long periods. Remote sensing is a reliable tool that can provide valuable informat... The monitoring of water quality in large coastal regions demands great analytical efforts through the collection of many samples, over long periods. Remote sensing is a reliable tool that can provide valuable information on the spatial and temporal variations of environmental parameters, particularly turbidity and chlorophyll a. The aim of the present research was to evaluate the spatial and temporal distribution of water quality from 2005 to 2017 along the north coast of S&#227;o Paulo and its responses to the implementation of industrial developments and to variations in rainfall. Fifty-two MODIS images were used, showing concentrations of chlorophyll a and turbidity, in the dry season and wet season, from 2005 to 2017. The results showed that dilution processes (due to rainfall) control chlorophyll a concentrations. However, a notable increase in concentrations could be identified after the installation of some of the developments in the region, particularly roads and ports. Turbidity was also shown to be affected by dilution processes, and during the wet season this parameter presented lower values. No effect in the results of turbidity could be identified from the installation of roads or ports, showing that vegetation cover exerts an important control on the erosional processes. 展开更多
关键词 Water Quality CHLOROPHYLL a TURBIDITY MODIS REMOTE Sensing
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