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191.
A chemometrical study of waste water data is carried out in order to reveal some new information about the pollution events in Yantra river basin, Bulgaria. Cluster analysis shows that no substantial difference in the behaviour of various sites along the river could be found if all chemical pollutants are simultaneously considered as variables (both for direct and indirect inlet of pollutants). Further, the clustering of the variables indicates a separation between organic and nutrition polluting species. The principal components analysis offered information about the latent factors influencing the data structure. In principle, three to four such latent factors explain over 80% of the total variance of the system. These factors are conditionally named “organic pollution”;, “nutrition pollution”; or “natural”; and are slightly different for the cases of direct and indirect inlet.  相似文献   
192.
The present paper deals with the impact of pesticides on water quality in Austria. Results of different monitoring programmes and surveys concerning the contamination of groundwater and running waters are provided; various aspects of sediment analyses and bioindication are also discussed. The evaluation of the data reveals a rather serious situation particularly in the eastern parts of the country intensively used by agricultural activities. The substances most often detected are triazines and lindane. Legal measures and key figures on the Austrian agriculture are also presented.  相似文献   
193.
SUMMARY

With the aim of evaluating the biotic pressure on a protected area, Kuldiha Sanctuary in Orissa, India was taken as a case study. In the 19 villages lying within a 1 km radius of the Sanctuary, there are 9814 people with 19% literacy. Tribals constitute 73.3% of the population. Some 7507 head loaders collect firewood from the Sanctuary every day. In addition, 37 297 cattle enter the forest for grazing. Consequently alienating the people depending on the Sanctuary in the management and conservation of wild flora and fauna is not only futile but also detrimental to the socio-cultural-economic fabric of the ecosystem of the people. In this study, involvement of the local community in the protection and management of the Sanctuary and National Park is proposed and methods of implementation, funding and a legal framework are discussed.  相似文献   
194.
长江口及邻近海域溶解铋的分布变化特征及影响因素   总被引:1,自引:0,他引:1  
利用氢化物发生原子荧光光谱法测定了长江口及邻近海域水体中溶解铋的含量,探讨了海水中溶解铋的分布特征、可能来源及影响因素.结果表明,在表、底两层水体中溶解铋含量分别为0.007—0.086 nmol.L-1和0.007—0.025 nmol.L-1,平均值分别为0.033 nmol.L-1和0.014 nmol.L-1.在空间分布上,表层水体中的溶解铋具有明显的梯度变化,在长江冲淡水所及区域含量较低.而在杭州湾及其同纬度地区的高值区可能是由于钱塘江等河流的输入及海水的平流作用引起.温度和盐度分布特征可以反映研究区域水团输入特征,研究表明,溶解铋含量与盐度呈显著负相关,而与温度呈正相关关系,进一步印证了水团输入对溶解铋空间分布的影响,同时也说明河口地区溶解铋在一定盐度范围内的行为是保守的,在河口地区并未发生明显转移.溶解铋除了受沿岸水体输入影响外,吸附-解吸附过程也是影响其分布的重要因素.研究显示,溶解氧、温度和pH是控制铋在颗粒物中吸附-解吸过程的主要环境因素,它们通过控制溶解度和吸附作用来影响水体中溶解铋的分布和地球化学行为.  相似文献   
195.
山东半岛蓝色经济区海域生态环境综合评价   总被引:1,自引:0,他引:1  
海域生态环境评价作为承载力研究的基础,在近海生态管理中得到了广泛关注. 针对海洋生态环境研究中评价指标体系简单、标准相对单一及不利于实际应用等问题,以生态系统为研究视角构建了基于环境因子和生态响应的近海生态环境综合评价指标体系与指数计量方法,根据环境因子指数和生态响应指数在交叉判断矩阵中的位置,将近海生态环境状态分为优、良、中、差和劣5个等级,并将该方法应用于山东半岛蓝色经济区海域评价. 结果表明:研究海域整体环境因子指数为0.41~0.84(平均值为0.67),生态响应指数为0.17~0.75(平均值为0.45),综合评价等级为良,但已非常接近中等级别;其生态环境问题主要表现为溶解无机氮负荷较高、重金属和浮游动物密度负荷过低. 不同海域生态环境状态存在明显差异,25个近岸海域中等级优和良的共占60%,主要分布在山东半岛东部和西南部;海域等级为中和差的各占16%,另有8%海域等级为劣. 该评价模型与方法从生态环境整体性揭示海域存在问题,可为山东半岛蓝色经济区建设提供科学依据.   相似文献   
196.
为了建立适用于工程上运用的尾矿坝漫顶逐渐溃坝的尾砂出流计算模型,利用细颗粒泥沙的悬移质运动形式,及含沙浑水的流态变化,建立了理论泄流模型。同时,根据溃坝过程的不同时期,给出了适宜的溃坝水流的流量计算公式、尾砂颗粒的沉速计算方法、挟沙力的计算方法以及浑水容重的计算式。该计算模型有助于渐溃泄沙量的预测,是尾矿坝漫顶逐渐溃坝模型的重要组成部分。  相似文献   
197.
在压力容器设计换证审查时,对施工图中封头的名义厚度和最小成形厚度标注及计算书的输入提出了质疑。对此以实例从封头的名义厚度影响许用应力及技术条件和最小成形厚度影响有效厚度及计算结果的准确性进而关系容器建造的安全可靠性进行了讨论,认为施工图设计应限定封头的名义厚度,最小成形厚度以标注为宜,而SW6数据输入应增加“成形减薄量C3”项。建议GB150的术语符号引入C3,GB/T25798应完善封头威形厚度减薄率,《压力容器定期检验规则》应监督封头制造的成形厚度减薄率,以为容器设计提供支撑。  相似文献   
198.
鸭绿江口潮滩沉积物间隙水中的营养盐   总被引:13,自引:0,他引:13  
通过对鸭绿江口潮滩区2个采样点采集的柱状样分析、培养实验,测定了沉积物间隙水中的营养盐和沉积物中的S2-结果表明,鸭绿江口潮滩区沉积物间隙水中的NO3-含量平均值为3.0μmol/L,垂直分布变化不大.PO43-和SiO32-的含量范围分别为0.8~70.4μmol/L,111.6~1054.3μmol/L,且两者垂直变化类似,随沉积物深度的增加先增加后下降.沉积物中硫化物的分布是随深度增加,含量升高.鸭绿江口潮滩区沉积物Eh、pH的测定结果显示,在13cm以下,Eh降为负值,沉积物还原性逐渐增强.而pH自上而下变化不大.由分子扩散公式计算结果表明,鸭绿江口潮滩区营养盐均由沉积物向上覆水扩散.  相似文献   
199.
Sharing waters: Post-Rio international water management   总被引:4,自引:0,他引:4  
Transcending human-defined political and administrative boundaries, the world's transboundary freshwater resources pose particularly challenging management problems. Water resource users at all scales frequently find themselves in direct competition for this economic and life-sustaining resource, in turn creating tensions, and indeed conflict, over water supply, allocation, and quality. At the international scale, where the potential for conflict is of particular concern, significant efforts are underway to promote greater cooperation in the world's international river basins, with notable achievements in the past decade following the Dublin and Rio conferences. Over the past ten years, the international community has adopted conventions, declarations, and legal statements concerning the management of international waters, while basin communities have established numerous new basin institutions. Despite these developments, significant vulnerabilities remain. Many international basins still lack any type of joint management structure, and certain fundamental management components are noticeably absent from those that do. An understanding of these weaknesses, however, offers an opportunity for both the international and basin communities to better respond to the specific institution-building needs of basin communities and thereby foster broader cooperation over the world's international water resources.  相似文献   
200.
ABSTRACT: The vertical hydraulic conductivity for upward and downward flow conditions was investigated under controlled laboratory conditions for intact cores of organic sediments from two south Florida wetlands ‐ one cypress dome and one emergent marsh. A modified falling head permeameter apparatus was constructed for this effort; the methodology for analyzing the data from the apparatus was generalized and simplified from a previously published version. For the two study wetlands, the hydraulic conductivity in the downward flow direction varied from 77 to 89 percent of that in the upward flow direction.  相似文献   
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