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71.
Environmental geochemistry and health of fluorine in Chinese coals   总被引:2,自引:0,他引:2  
Fluorine is one of the potential hazardous trace elements in coal. Fluorine may be released into atmosphere mostly during coal combustion process. When the coal is burning indoors without any controlling methods (chimney), the fluorine will pollute the room and is absorbed by food fired (dried) over stoves. Now many people have suffered from fluorosis due to coal burning indoors in Southwest China. In this paper, the concentration, distribution, mode of occurrences and impact factors of fluorine in Chinese coals are analyzed. The environmental impacts and typical features of fluorosis are studied. It is concluded that the value of fluorine in Chinese coals ranges from 20 to 300 mg/kg, and with average value of 122 mg/kg from 5,603 coal samples. It is higher than the average value of the world coals (80 mg/kg). In provincial coalfields of the SW China, the content of F is highest and many people have been affected due to coal combustion indoors.  相似文献   
72.
Peter Kraftl  John Horton 《Geoforum》2007,38(5):1012-1027
This paper is about a single event: a conference (A.K.A. ‘the health event’) held in the English East Midlands in July 2005, at which findings from a policy-led research project regarding young people’s health needs were fed back to research participants. The paper foregrounds some of the everyday work, happenings, emotions, conversations and materialities which were fundamentally constitutive of ‘the health event’ and, thus fundamentally constituted the moments of affirmative, politically-charged participation which could and did happen therein. Thus the paper bears witness to the sorts of practices, minutiae and highs and lows which are surely fundamentally constitutive of participation, policy and politics per se, but which (despite the growing visibility of nonrepresentational theories) are typically absent from salient accounts of participation, Children’s Geographies and Post-medical Geographies.  相似文献   
73.
This paper describes the spatiotemporal epistematics knowledge synthesis and graphical user interface (SEKS–GUI) framework and its application in medical geography problems. Based on sound theoretical reasoning, the interactive software library of SEKS–GUI explores heterogeneous (spatially non-homogeneous and temporally non-stationary) health attribute distributions (disease incidence, mortality, human exposure, epidemic propagation etc.); expresses the health system’s dependence structure using (ordinary and generalized) spatiotemporal covariance models; synthesizes core knowledge bases, empirical evidence and multi-sourced system uncertainty; and generates a meaningful picture of the real-world system using space–time dependent probability functions and associated maps of health attributes. The implementation stages of the SEKS–GUI library are described in considerable detail using appropriate screens. The wide applicability of SEKS–GUI is demonstrated by reviewing a selection of real-world case studies. An erratum to this article can be found at  相似文献   
74.
The extremely heterogeneous distribution of As in Bangladesh groundwater has hampered efforts to identify with certainty the mechanisms that lead to extensive mobilization of this metalloid in reducing aquifers. We show here on the basis of a high-resolution transect of soil and aquifer properties collected in Araihazar, Bangladesh, that revealing tractable associations between As concentrations in shallow (< 20 m) groundwater with other geological, hydrological, and geochemical features requires a lateral sampling resolution of 10–100 m. Variations in the electromagnetic conductivity of surface soils (5–40 mS/m) within a 500 m × 200 m area are documented with 560 EM31 measurements. The results are compared with a detailed section of groundwater As concentrations (5–150 μg/L) and other aquifer properties obtained with a simple sampling device, “the needle-sampler”, that builds on the local drilling technology. By invoking complementary observations obtained in the same area and in other regions of Bangladesh, we postulate that local groundwater recharge throughout permeable sandy soils plays a major role in regulating the As content of shallow aquifers by diluting the flux of As released from reducing sediments.  相似文献   
75.
Groundwater quality in parts of Central Ganga Basin, India   总被引:1,自引:0,他引:1  
 This paper deals with the drinking water quality of the Ganga-Kali sub-basin which occupies 1300 km2 over parts of Aligarh and Etah districts. Water samples were collected from shallow and deep aquifers and were analyzed for major ions and trace elements. The analytical data were interpreted according to published guidelines. Chemical analysis shows that the groundwater in the basin is alkali bicarbonate type. Trace element studies of water from the shallow aquifer show that the concentration of toxic metals Fe, Mn, Cd, Pb, and Cr+6 are above permissible limits which may present a health hazard. The water from the deep aquifer is comparatively free from contamination. The aquifers are subject to contamination due to sewage effluents and excessive use of fertilizers and pesticides in agriculture. Received: 7 December 1998 · Accepted: 2 March 1999  相似文献   
76.
Following the 2010 and 2011 earthquake and aftershocks in Canterbury, New Zealand, extensive research was carried out on the rockfall hazard to residential buildings on Christchurch's Port Hills. To determine which dwellings faced an unacceptable risk to life safety, the recommendation was made to adopt a tolerable threshold for individual risk of 1/10,000 p.a. (10?4 p.a.). The 10?4 p.a. threshold has subsequently been considered for application to other natural hazards. However, this threshold is far too high. It is about 35 times higher than the post-colonial historic average for natural hazards, it is 100 times greater than New Zealand's structural design standard for new buildings and it is 10–100 times greater than the risk tolerated by comparable jurisdictions for existing and new risks, respectively. A more appropriate threshold for the risk from natural hazards is within the range from 10?5 p.a. for existing exposure to 10?6 p.a. for new exposure. The reason for adopting this arbitrarily high threshold for rock roll hazard appeared to be to balance an overestimation of calculated risk given the large uncertainties inherent in the data. However, there are some concerns if this acceptance criterion is applied to other natural hazards where underlying risk might be more accurately estimated.  相似文献   
77.
It is likely that there will be a substantial increase in the number of tidal stream turbines within the UK over the next decade. However, the ecological impacts upon marine top-predators, including seabirds, remain largely unknown. Although tidal stream turbines could have many direct and indirect impacts upon seabird populations, it is the risk of direct collisions between individuals and moving components that currently causes the most concern. Species such as Auks Alcidae sp., Cormorants Phalacrocorax sp. and Divers Gavia sp. almost certainly face higher risks than others. However, it is likely that they are not equally vulnerable. Part of predicting which are most vulnerable involves the estimation of spatial overlap between their foraging distributions and the location of tidal stream turbines. This paper reviews potential methods and approaches that should help to predict whether a population would: (1) exploit areas suitable for tidal stream turbines, (2) dive near tidal stream turbines within these areas, or (3) dive to depths where moving components are found? Answering these questions in a hierarchical manner (from 1 to 3) could help to predict the extent of spatial overlap for vulnerable populations. These approaches require a fundamental understanding of the mechanistic links between physical conditions, prey characteristics and foraging opportunities. Therefore, multi-disciplinary approaches incorporating methods usually associated with oceanographic and fisheries studies are needed to document physical conditions and prey characteristics over large and small spatial scales. Answering these questions also requires collaborative efforts and a strategic governance approach to collating the wide range of distributional, prey and physical datasets currently being collected.  相似文献   
78.
近几年来"无人机"逐渐成为热门话题,汉川地震和玉树地震中的出色表现,又让"无人机航拍"这一话题深入人心,吸引了越来越多的人去学习研究,各地测绘部门和国家领导人的支持更促进了国内无人机技术的迅速发展.从当前无人机应用过程中存在的问题入手,针对几个关键问题进行了简要论述,并提供了一些相应对策.  相似文献   
79.
Structural monitoring is essential for ensuring the structural safety performance during the service life. The process is of paramount importance in case of the offshore jacket-type platforms due to the underwater structural parts subjected to the marine environmental conditions. This work is an experimental investigation on a laboratory model of a jacket platform with the objective of establishing a baseline finite element (FE) model for long-term structural health monitoring for this type of structures. A robust damage diagnosis system is also developed which is less sensitive to both the measurements and the modeling uncertainties. Experimental vibration tests are conducted on a physical platform model to obtain dynamic characteristics and then, the initial FE-model of the intact structure is developed to determine them numerically. Some differences between numerically and experimentally identified characteristics emerge due to various uncertainties in the FE-model and measured vibration data. To minimize these differences, initial FE-model is updated according to the experimental results. The updated FE-model is employed to predict the changes in the dynamic characteristics under variety of damage scenarios which are imposed by reducing the stiffness at the components of the model. Fuzzy logic system (FLS) and probabilistic analysis is developed for linguistic classification of damage and global damage diagnosis. Incorporation of the FLS fault isolation technique into FE-model updating method are proposed and evaluated for two different FLS methods to develop a vigorous damage diagnosis method. The efficiency of the technique is validated by different damage scenarios foreseen on the physical model. This technique is shown to be effective for diagnosing the presence of degradation and quantify it.  相似文献   
80.
Karst groundwater is a vital resource for drinking, living and irrigation purposes in karst agricultural areas of the world. Due to the vulnerability of karst aquifers, surface pollutants are easily transferred to the subsurface and make karst groundwater be deteriorated, thereby restricting the rational exploitation of karst groundwater resource. In view of this, 49 karst groundwater samples were collected from spring (SW) and underground river (URW) sites in the suburban area of Chongqing City and analyzed for various hydrochemical components. Particularly, the karst groundwater quality was comprehensively uncovered by combining characteristics of hydrogeochemical evolution and health risks caused by nitrate and fluoride. The results revealed that the karst groundwater was slightly alkaline in nature and the water types were mainly characterized by Ca-HCO3 accounting for 93.88% of the total samples due to the heavy dissolution of carbonate rock. The relatively high concentrations of Na+, SO42? and NO3? up to 271.88 mg/L, 277.94 mg/L and 56.94 mg/L were over the corresponding maximum acceptable limits for drinking water, which can be predominately attributed to the emissions of industrial park, dissolution of gypsum and pyrite and excessive application of chemical fertilizers. Although agricultural activities were stopped and chemical fertilizers were no longer applied during the sampling period, long-term application of fertilizers have a persistent adverse effect on the karst groundwater NO3?. The pollution index of the karst groundwater (PIG) revealed that the low pollution and potential pollution zones were noticed in the northwestern parts of the study area. With respect of the SW, all the total hazard index (HI) values were below 1 suggesting no significant health risk. On the contrary, HI values of 0.11–1.16 for adults, 0.15–1.61 for children and 0.17–1.83 for infants in the URW indicated significant noncarcinogenic health risks. Particularly, infants and children were more vulnerable to karst groundwater NO3? than adults. Furthermore, the noncarcinogenic health risks of karst groundwater can be mainly attributed to NO3?, confirmed by the higher contribution ratio (66.55%) to the HI values. Therefore, special and targeted measures need to be taken to decrease the NO3? concentration in agricultural area.  相似文献   
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