| 摘要 | 汞污染是全球性的环境问题.从20世纪50年代日本水俣湾汞中毒事件,到最近十年来,在北美及欧洲偏远地区的湖泊中发现鱼体汞含量超标,汞污染的研究一直受到人们的重视,是世界环境污染研究的热点之一.随着对全球汞生物地球化学循环研究工作的不断加深,对其的研究难度逐渐增加,以往单一的研究方法已难见成效.越来越多的研究者认识到,只有将地学领域中采用不同研究方法(地质、地球物理和地球化学等方法)所得到的信息,进行综合分析研究,才能更清楚的了解全球汞的生物地球化学循环.近年来计算机技术的发展,特别是GIS技术的出现,使得这一设想成为现实.地理信息系统(GIS),在一个灵活的空间数据管理环境中,将从不同方面采集、存储和分析的数据提供给用户.用户利用GIS数据中的各种相关的空间或非空间信息,进行各种综合分析研究,从而对全球汞的生物地球化学循环提出新的认识和作出科学的论断.该文偿试将地理信息系统应用在汞的生物地球化学循环研究中.论文的主要内容包括以下两部分:1)地理信息系统的核心是空间数据库,该文建立了贵州省汞地球化学数据库.应用ArcGIS中的MapObjects控件和VB技术相结合开发的贵州省汞地球化学数据库,既能充分发挥管理的优势,又能快速产生友好用户界面,具有快捷、方便、高效等特点.该数据库为贵州省汞地球化学循环研究提供了空间数据管理功能,不仅可以存储大量的空间数据和属性数据,还可以进行空间数据输入、浏览、查询、删除和输出及属性表数据的查询、分析和输出.贵州省汞地球化学数据库为政府决策部门提供了环境监测数据和决策支持系统,也有利于世界范围内汞地球化学研究数据的交流.2)应用贵州省汞地球化学数据库中的贵阳市土壤汞含量数据图,结合贵阳市土壤一大气汞交换通量数据,用多元回归的方法对贵阳市土壤向大气年排汞量进行了估算,结果为:年释汞通量为652Kg,变化范围为463~919Kgyear<'-1>.单位面积的平均释汞量为193~382gKm<'-2>year<'-1>.对比全球背景值,贵阳市土壤年释汞通量的预测值总体偏高,主要是贵阳市的亚热带气候和土壤汞含量偏高的影响.与贵阳市燃煤年排汞量相比,贵阳市土壤释汞通量为0.652tyear<'-1>,仅为目前燃煤排汞量的1/3.说明贵阳市大气汞的来源还是以人为污染为主,但被污染的土壤对大气汞也有不可忽视的贡献. |
| 其他摘要 | Mercury is a global pollutant. From 1950s when Minamata disease occurred in Japan to the last two decades when mercury concentrations in fish from remote areas of northern America and northern Europe were discovered to be higher than the advisory limit recommended by WHO, mercury pollution in the environment has been an hotspot issue and tremendous efforts have been diverted to understand the global biogeochemical cycle of this metal. Recent advances have demonstrated that the mercury cycle is much more complicated than previously realized. A single way is difficult to research the global cycle of mercury. Many researchers know that we can distinctly understand the global cycle of mercury if using many kinds of methods together. With the advancement of computer technique, geographical information system (GIS) is developing rapidly, which can offer user the data which are collected, stored and analyzed from different aspects in a live environment of spatial data management. The user can put forward new cognition and gain scientific conclusions through analyzing all kinds of correlative or incorrelative spatial information. We research application of GIS to the biogeochemical cycle of mercury. There are two main research topics in this thesis, namely, Spatial database is the core of geographical information system(GIS). Using geographical information system (GIS), We establish the spatial database about the biogeochemical cycle of mercury in Guizhou Province. This spatial database which develop with MapObjects and VB can offer users neighbor client support, and it is excellent, such as rapidness, handling facility and optimum efficiency. This spatial database can provide a function to manage spatial data-a number of spatial data and attributes data can be stored, digitized, input, browsed, searched, deleted, output etc. It can offer governmental decision-making department many environmental data by which government can decide what they will do next. Meanwhile, the geochemical data of mercury in Guizhou Province can be used for the global pwple in this spatial database. We estimate the flux from soil to air every year in Guiyang. This study quantified the mercury emissions from Guiyang. Area emissions were calculated using . Geographic Information System technology, and in situ derived mercury fluxes and those parameters found to statistically be dominant in controlling emissions. The most important controls on emission strengths were found to be Hg concentration in the soils while environmental parameters such as light were found to drive the diel pattern typically observed for mercury emissions;. These emissions are an order of magnitude higher than values applied in global models for natural sources. This study, along with other recent work, demonstrates that natural sources may be an important atmospheric mercury source in Guiyang. |
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