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1.
谢明义 《四川环境》1998,17(4):32-35
本文介绍了成都市大气尘放射性水平的监测结果。发现除尘中除少量天然核素外,还尚存在以往大气层柱试验释放的裂变核素^90Sr和^137Cs。  相似文献   

2.
利用煤吸附处理含铬废水及生活污水的试验研究   总被引:4,自引:0,他引:4  
本文研究了四川白皎无烟煤用于生活污水、含铬废水和乐果生产废水的处理。在静态条件下,煤对生活污水中的COD去除率为12%;对乐果生产废水的脱色率大于638%;在含铬工业废水在浓度为3526×10-5mol·dm-3时Cr(VI)的去除率为90%左右。考察了固液比、温度、浓度和酸度等对煤吸附Cr(VI)的影响,并发现吸附量q与时间t之间遵从如下的定量关系:q=47685(1+21256t)-1或q=21351[1-exp(-05016t)]03838  相似文献   

3.
本文对U,K,^137Cs,^90Sr等几种核素在土壤-水稻,土壤-茶叶,土壤-蔬菜之间以及水-鱼间的转移情况进行了研究;并考虑到这些核素含量较高的食品(如茶叶、黄豆)不直接全部食入人体,因此,根据人们的饮茶习惯及豆制品(水豆腐)的加工过程进行模拟,对其向人体转移的参数进行了实验研究。由上述实验结果给出了转移参数及相关方程。  相似文献   

4.
中国工程物理研究院核 物理与化学研究所原工作地点(老点)存在两个放射性废物库537-1和537-2。年内分别在库周围取地下水(或土)6次,对537-1得到地下水和泥土中的铀含量大约为1.27μg/L和3.0μg/L,对537-2得到的地下水中的90Sr含量约为5.35×10-3Bq/L。上列数据与本底无明显差异。可见,537-1废物库周围地下水中铀含量与生活区河水中含量无明显差异,537-2废物库周围地下水中锶含量与生活区河水中含量也无明显差异。至今未监测到两个废物库中的放射性核素对周围地下水中的明显 影响。  相似文献   

5.
本文了用固体径迹法对四川省科学城地区297个监测点进行了为期一年的室内氡浓度调查,测得了生活区室内氧浓度的年平均值(495Bq·m-3)和工作区室内氡浓度的年平均值(554Bq·m-3)。  相似文献   

6.
无源累积氡法监测成都,自贡环境空气中的氡   总被引:1,自引:0,他引:1  
本文报道固体核径迹法测定成都、自贡市的环境氡水平。1991年在成都市布放探测器4个月,34个室内测点平均氡浓度36.6±17.4Bq·M ̄-3;2个室外点平均16.2±4.2BqM ̄-3。1992年在自贡市6个区域布放67个探测器,64个测点平均氡浓度49.2±24.5Bq·M ̄-3。有3个测点,探测器上出现局部高密集氡径迹,重要探索,未统计入内。若以上述室内氡平均值和环境氡平均植分别代表两市的全年氡平均水平,并以室内公众成员所受平均氡浓度与年有效剂量关系式计算。成都、自贡市公众成员各自受氡年有效剂量当量为1.10mSv和1.48mSv.  相似文献   

7.
本文报道了自贡市井矿盐开发所致的辐射水平。井矿盐开发的主要废弃物-卤泥中^238U,^226Ra,^232Th的天然放射性核素比活度比四川省土壤中相应核素平均值高1-2个数量级,且造成卤泥堆积场和局部生产环境陆地γ辐射剂量率高出自贡市环境陆地γ辐射平均值的2.0-48.3倍,最主超过165倍。部份卤泥和盐厂附近江河排放口底泥中天然放射性废物标准。  相似文献   

8.
小果蔷薇的开发利用   总被引:2,自引:0,他引:2  
1植物学特性及其生活环境与分布[1~2]小果蔷薇(RosacymosaTrat)属蔷薇科蔷薇属的野生植物,为攀援灌木,高2m~5m,小枝细,无毛或稍有毛,具钩状下弯的皮刺。小叶3~5,少数7,椭圆形至卵状披尖形,长25cm~6cm,宽08cm~2...  相似文献   

9.
工业燃煤锅炉大气污染物控制技术(续)POLLUIONCONTROLFORINDUSTRIALCOAL-FIREDBOILERS(cont.)三、so2排放控制煤中含硫量多少决定SO2的排放量,因为只有一小部分硫在燃烧后仍残留在煤灰中。目前工业锅炉SO...  相似文献   

10.
本文对UASB-Fe装置处理城市污水进行了中试研究,结果表明,当厌氧HRT3-4小时,进水浓度总CODcr为241.2-402.3mg/l,溶BOD5为80.6-136.8mg/l,SS为170.8-189.8mg/l时,其平均去除率依次为42.1-56.6%,64.0-39.8%和72.9-65.4%。讨论了厌氧HRT,进水浓度,温度等因子对厌氧处理效果的影响情况。浅析了铁填料层在城市污水处理中  相似文献   

11.
Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation.  相似文献   

12.
Urban ecological systems: scientific foundations and a decade of progress   总被引:9,自引:0,他引:9  
Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs.  相似文献   

13.
Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered.  相似文献   

14.
Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions.  相似文献   

15.
Water treatment residuals (WTR) can reduce runoff P loss and surface co-application of P-sources and WTR is a practical way of land applying the residuals. In a rainfall simulation study, we evaluated the effects of surface co-applied P-sources and an Al-WTR on runoff and leacheate bioavailable P (BAP) losses from a Florida sand. Four P-sources, namely poultry manure, Boca Raton biosolids (high water-soluble P), Pompano biosolids (moderate water-soluble P), and triple super phosphate (TSP) were surface applied at 56 and 224kgPha(-1) (by weight) to represent low and high soil P loads typical of P- and N-based amendments rates. The treatments further received surface applied WTR at 0 or 10gWTRkg(-1) soil. BAP loss masses were greater in leachate (16.4-536mg) than in runoff (0.91-46mg), but were reduced in runoff and leachate by surface applied WTR. Masses of total BAP lost in the presence of surface applied WTR were less than approximately 75% of BAP losses in the absence of WTR. Total BAP losses from each of the organic sources applied at N-based rates were not greater than P loss from TSP applied at a P-based rate. The BAP loss at the N-based rate of moderate water-soluble P-source (Pompano biosolids) was not greater than BAP losses at the P-based rates of other organic sources tested. The hazards of excess P from applying organic P-sources at N-based rates are not greater than observed at P-based rates of mineral fertilizer. Results suggest that management of the environmental P hazards associated with N-based rates of organic materials in Florida sands is possible by either applying P-sources with WTR or using a moderate water-soluble P-source.  相似文献   

16.
The interactions between humans, animals and the environment have shaped human values and ethics, not only the genes that we are made of. The animal rights movement challenges human beings to reconsider interactions between humans and other animals, and maybe connected to the environmental movement that begs us to recognize the fact that there are symbiotic relationships between humans and all other organisms. The first part of this paper looks at types of bioethics, the implications of autonomy and the value of being alive. Then the level of consciousness of these relationships are explored in survey results from Asia and the Pacific, especially in the 1993 International Bioethics Survey conducted in Australia, Hong Kong, India, Israel, Japan, New Zealand, The Philippines, Russia, Singapore and Thailand. Very few mentioned animal consciousness in the survey, but there were more biocentric comments in Australia and Japan; and more comments with the idea of harmony including humans in Thailand. Comparisons between questions and surveys will also be made, in an attempt to describe what people imagine animal consciousness to be, and whether this relates to human ethics of the relationships. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

17.
This study demonstrates the integration of rehabilitation and flood management planning in a steep, boulder-bedded stream in a coastal urban catchment on the South Island of New Zealand. The Water of Leith, the primary stream flowing through the city of Dunedin, is used as a case study. The catchment is steep, with a short time of concentration and rapid hydrologic response, and the lower stream reaches are highly channelized with floodplain encroachment, a high potential for debris flows, significant flood risks, and severely degraded aquatic habitat. Because the objectives for rehabilitation and flood management in urban catchments are often conflicting, a number of types of analyses at both the catchment and the reach scales and careful planning with stakeholder consultation were needed for successful rehabilitation efforts. This included modeling and analysis of catchment hydrology, fluvial geomorphologic assessment, analysis of water quality and aquatic ecology, hydraulic modeling and flood risk evaluation, detailed feasibility studies, and preliminary design to optimize multiple rehabilitation and flood management objectives. The study showed that all of these analyses were needed for integrated rehabilitation and flood management and that some incremental improvements in stream ecological health, aesthetics, and public recreational opportunities could be achieved in this challenging environment. These methods should be considered in a range of types of stream rehabilitation projects.  相似文献   

18.
ABSTRACT: This paper presents a statistically valid index for measuring the performance of irrigation systems. The index is applied to a sample of 39 farms on a watercourse under the warabandi system of irrigation management in India. It is found that while the farmers in fact irrigated almost exactly the total amount of irrigated area as designed, inter-farm variations were considerable. The index shows that the degree of error of managerial effectiveness of irrigation on this watercourse is 20 percent. Therefore it is concluded that the system is performing at 80 percent effectiveness.  相似文献   

19.
Infiltration models are based on physical characteristics of the soil and initial soil moisture. For a given soil it is based on the initial soil moisture distribution. A computer simulation model for flood runoff systems (FH-Model) was used to analyze 39 sets of rainfall-runoff data on four small watersheds ranging in size from 17 to 342 square kilometers located in the Yamaska River basin in Quebec. From these analyses, parameters and coefficients have been determined for a water loss (infiltration) equation. A method for determining the loss parameters, using a nonlinear least square curve fitting technique, is presented. Expressions were made to relate the loss parameters to antecedent precipitation. The equations were tested on 11 storm rainfall and runoff events on a watershed located in the same region and close agreements were found.  相似文献   

20.
Data are presented on the vegetation dynamics of two impounded marshes along the Indian River Lagoon, in east-central Florida, USA. Vegetation in one of the marshes (IRC 12) was totally eliminated by overflooding and by hypersaline conditions (salinities over 100 ppt) that developed there in 1979 after the culvert connecting the marsh with the lagoon was closed. Over 20% recovery of the herbaceous halophytesSalicornia virginica, S. bigelovii, andBatis maritima was observed at that site after the culvert was reopened in 1982, but total cover in the marsh remains well below the original 75%. No recovery of mangroves was observed at this site. The second site (SLC 24), while remaining isolated from the lagoon during much of the study, did not suffer the complete elimination of vegetation experienced at the first site. At this location, mangroves increased in cover and frequency with a concomitant decrease in herbaceous halophytes. Considerable damage to the vegetation was evident at IRC 12 when the impoundment was closed and flooded for mosquito control in 1986. Although the damage was temporary, its occurrence emphasizes the need of planning and constant monitoring and adjustment of management details as conditions within particular marshes change. Storms and hurricanes may be important in promoting a replacement of black mangroves by red mangroves in closed impoundments because the former cannot tolerate pneumatophore submergence for long periods of time. University of Florida-IFAS Journal Series R-00521.  相似文献   

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