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1.
Radon-222 was measured in groundwater sources of Extremadura (Spain), analyzing 350 samples from private and public springs, wells, and spas by liquid scintillation counting (LSC) and gamma spectrometry. The 222Rn activity concentrations ranged from 0.24 to 1168 Bq L−1. The statistical analysis showed a log-normal distribution with a mean of (111 ± 7) Bq L−1 and a median of (36 ± 3) Bq L−1. A hydrogeological study revealed correlations between the activity concentration and the aquifer material's characteristics. A map of 222Rn in groundwater was elaborated and compared with the natural gamma radiation map for this region. About 35% of the samples showed 222Rn activity concentrations above the Euratom recommended limit of 100 Bq L−1. Three uranium series radionuclides (238U, 234U, and 226Ra) were also assayed by alpha-particle spectrometry, estimating the annual effective dose due to the presence of these natural radionuclides in drinking water.  相似文献   

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3.
To study the Pu concentration and isotope ratio distributions present in China, the 239+240Pu total activities and 240Pu/239Pu atom ratios in core soil samples from Hubei Province in central China were investigated using Accelerator Mass Spectrometry (AMS). The activities ranged from 0.019 to 0.502 mBq g−1 and the 239+240Pu inventories of 45 and ∼55 Bq m−2 agree well with that expected from global fallout. The 240Pu/239Pu atom ratios in the soil ranged from 0.172 to 0.220. The ratios are similar to typical global fallout values. Hence, any close-in fallout contribution from the Chinese nuclear weapons tests, mainly conducted in the 1970s, must have either been negligible or had a similar 240Pu/239Pu ratio to that of global fallout. The top 10 cm layer of the soil contributes ∼90% of the total inventory and the maximum concentrations appeared in the 2-4 cm or 4-6 cm layers. It is suggested that climatic conditions and organic content are the two main factors that affect the vertical migration of plutonium in soil.  相似文献   

4.
Reuse of mining wastewater in agricultural activities in Jordan   总被引:1,自引:0,他引:1  
A pilot study was completed in the Al-Abyad area near phosphate mining activity in Jordan. Six plots of 50 m2 each were planted with two types of plant species (Zea mays spp. and Medicago lupulina spp.) and irrigated using three types of water (fresh groundwater, mine wastewater, and hydride water consisting of 50% fresh and 50% mine wastewater) to investigate the suitability of utilizing mine wastewater for food production in the area. Water, soil and plant sampling was completed for each plot over different time intervals and analyzed for heavy metal (Cr+6, Ni+2, Zn+2 and Pb+2) in addition to major ionic composition of the water used for irrigation. Crop yield was estimated at the end of the experiment. Plots irrigated with mine wastewater showed slightly higher heavy metals concentrations and soil salinity during the experiment period was higher for plots irrigated with mine wastewater compared to plots irrigated with fresh water, and it was uniform through the upper 45 cm of the soil profile due to the high amount of irrigation water used during the experiment. Crop yield was inversely proportional to salinity as an increase of salinity by 2-folds resulted in reducing yield by almost 50%. However, no risk of heavy metals contamination was found in plants and soil. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   

5.
In Latvia, the concept of sustainability is only slowly gaining recognition. An analysis of Development Plans prepared by the four largest cities of Latvia indicates that sustainability is presented as one of the guiding principles. However, a comparison of Development Plan policies against the urban sustainability issues reveals a great deal of ambiguity and contradiction.At the municipal level, planners and politicians lack indicators to gauge whether the long-term goals of Development Plans and the principles of sustainable development are being achieved. As a consequence, the broad public is deprived of the opportunity to assess for itself the process of development in relation to Development Plan policies, thus limiting accountability in development decision-making. Relevant statistical data collected on a regular basis are required to create sustainability indicators reflecting sustainability issues, to supplement and replace existing statistical compilations pertaining almost exclusively to economic growth and consumption. Development and utilisation of sustainability indicators can be an effective instrument for promoting the values of sustainable development amongst politicians, planners and the broad public and for enhancing accountability in decision-making.  相似文献   

6.
The EU directives on e-waste management (WEEE and RoHS) have drawn the attention of electronics producers around the world to the environmental benign technologies in recent years. One of the technological challenges to the electronics manufacturers is the adoption of the lead-free soldering system. This article studies the diffusion of lead-free soldering technology among the electronics producers in China, and finds out the relevance of clusters for the diffusion of environmental benign technological innovation among firms. Four agents, as key promoters, were identified within the production network –leading global brand-name companies, the OEM companies who provide integrated manufacturing service, the suppliers of lead-free components, and specialized consultant companies. The conclusion is that industrial cluster facilitates communications among all agents for the diffusion of innovation, whereas, the incentives for firms within the cluster, to collaborate for innovation, comes from outside.  相似文献   

7.
Long-term observations on needle transpiration in pine and spruce, the main forest-forming tree species in the North, made it possible to estimate the rate of this process depending on different ecological factors in years with different weather conditions. Using a large amount of data, an attempt was made to compare transpiration rates in pine and spruce and reveal some specific features of this process under conditions of the North.  相似文献   

8.
It was shown that along the Eastern Ural Radioactive Trace central axis, about 100 km in length, decrease of the 90Sr and 137Cs deposition densities in soil samples may be described as an exponential function. At the western and eastern periphery of the trace, 90Sr contents in soils approached to the background level due to global fallout. 90Sr and 137Cs concentrations in seeds of some herbaceous plants have been determined. The radionuclide concentrations and the resulting dose loads upon plant seeds showed an excess over the background level of about two or three orders of magnitude.  相似文献   

9.
流域土地利用变化的水质响应研究进展   总被引:2,自引:0,他引:2  
探讨流域土地利用变化的水质响应,有利于从源头上控制水污染。不同学者在多种边界条件下研究了流域土地利用变化的水质响应,发现流域土地利用变化是造成河流水质发生变化的重要原因。根据是否可以将土地利用活动概化为点状,流域土地利用变化的水质响应研究可分为点状土地利用的水质响应和非点状土地利用的水质响应。准确边界土地利用的水质响应一般是研究流域土地利用空间特征和土地利用结构与水质变化的关系。对于用全流域尺度还是用缓冲区的尺度分析土地利用的水质响应更准确仍存在争论。水域边缘几何形状影响了土地利用与水质的关系。  相似文献   

10.
The dynamics of habitat distribution in two bird species differing in the level of site tenacity—willow warbler (relatively tenacious) and little bunting (more flexible)—were studied at the boundary of the northern taiga and forest–tundra zones over ten years. The distribution pattern proved to be more uniform in the willow warbler than in the little bunting. Both species occupied their habitats according to a well-known scheme: initially, the birds settled in their favorable floodplain habitats and later; when their abundance increased, in less preferable habitats (terraces above the floodplain, moss bogs, and the tundra). In the case of willow warbler, the process of occupying the floodplain was stepwise: bird density increased sharply, remained at the same level in the next year, then increased again, etc. In the case of little bunting, the degree of floodplain occupation by birds remained high, except for the years when high spring floods interfered with bird settling.  相似文献   

11.
In order to understand the short-term response of private car owners to changes in the price of oil, a survey was conducted in Beijing after the gasoline price in China rose in June 2008. It showed that private car drivers in Beijing reduced their trips in the one month period following the price adjustment. Certain trip characteristics and drivers' demographics significantly influenced price elasticity in the short term, including the purpose of the trip, the distance covered and the income of the car driver.  相似文献   

12.
This paper presents the results of the monitoring programme on the urines of people living in an area of Central Italy (near the Republic of S. Marino) to evaluate the background level of the 210Po excretion rate (mBq day−1) in this region. The volunteers were subdivided in five age classes and in every age class groups of males and females, cigarette smokers and non-smokers were taken into account. The results indicated that the 210Po excretion rate was widely distributed within each group of volunteers. The 210Po excretion rate was <30 mBq day−1 for 93.2% of people. The obtained results are discussed and some conclusion, based upon the average values, was drawn.  相似文献   

13.
中国实施生态旅游认证的机遇与挑战   总被引:18,自引:0,他引:18  
在界定生态旅游认证、分析建立生态旅游认证体系意义的基础上.对绿色环球21、澳大利亚的NEAP、厄瓜多尔的Smart Voyager等目前国际知名的认证体系进行了介绍.重点分析了中国实施生态旅游认证的机遇和面临的挑战,并对我国建立生态旅游认证体系的必要性及相关问题提出了建议。  相似文献   

14.
我国南方地区50 a冬季降水和相对湿度特征分析   总被引:1,自引:0,他引:1  
根据中国地面气候日值数据集资料,利用气候趋势系数、气候倾向率等方法,研究了我国南方地区冬季50 a降水和湿度的时空变化特征,并运用基尼系数对降水均匀性的空间分布进行了分析。结果表明:降水和相对湿度分布皆自西北向东南递增,最大中心位于长江以南附近内陆区域,最小值基本位于高原。降水强度整体呈现增加趋势,在沿长江附近区域以及云南部分地区增强明显,最大气候倾向率为1.0 mm/d/10 a左右,有明显的突变时间,为1979年;降水量呈微弱的增加趋势,其中云贵和川渝局部区域降水量呈减少趋势,为-3 mm/10 a左右,没有明显的突变时间;降水日数在长江以南局部区域及云贵区域显著减少,其中云南的西南地区为最小气候倾向率-10 d/10 a,明显突变时间为1980年;相对湿度表现出一定的局地增减趋势,长江以北(南)主要呈微弱增加(减少)趋势,云南南部减小趋势显著;相对湿度和降水呈明显的正相关,其中与降水量和降水日数相关系数高达0.784、0.753。降水量基尼系数的空间分布与降水分布相似,只是降水分布的大(小)值中心为基尼系数小(大)值中心,不同年代及冬季不同月份的降水量基尼系数大(小)值区域范围有所增减。总的来看,我国南方冬季中部和东部大部分区域为降水均匀区,西南高原区域为不均匀区。 关键词: 南方地区;冬季;降水;相对湿度  相似文献   

15.
The objective of this article is to address the environmental costs of pig farms in the La Piedad region Mexico, through an analysis of the standard on wastewater discharges to national water bodies. Field work was carried out from April to September 1999; a survey was conducted on 23 farms and samples of wastewater were taken on 11 farms. Pig production is the third most important system in Mexican livestock production. Heterogeneity in production systems, dependence on imported inputs (genetics and feed grains), and weak internalization of environmental costs are the main characteristics of pig production in Mexico. With no specific environmental regulations on intensive livestock activities at the municipal or state levels, Mexican Official Standard 001 on wastewater discharges is the only environmental obligation that pig farms must meet. Standard 001 on wastewater contains the maximum permissible limits for 20 contaminant parameters, and is based on a cost-benefit analysis that points to secondary treatment for the regulation’s economic viability. Investment in treatment systems and the fees that pig producers must pay when they fail to comply with the limits stipulated in the regulation, are estimated assessed as an approach to environmental costs. In order to remain within the limits in the standard, pig farms must invest in tertiary treatment, and that makes meeting the standard unaffordable for this sector.  相似文献   

16.
Kinetic of fuel particles dissolution under natural environmental conditions has been investigated using the data on (90)Sr speciation in soils collected from 1995 to 1997 within the Chernobyl nuclear power plant 50 km zone. The dependency of fuel particles dissolution constants on the soil acidity (pH = 4-7) has been obtained on the basis of large and statistically reliable experimental data. Results show that between 2 and 21% of (90)Sr activity is associated with weathering resistant fuel particles. Therefore, these particles would not influence the radiological situation in the near future. The map of the main agrochemical characteristics and the map of the fuel particles dissolution constants have been created for the 30-km zone territory. According to the prognosis of dynamics of fuel particles dissolution in the investigated zone, a radiological situation along the fuel paths of radioactive fallout in present time reached a stable state. An increasing in absolute contents of (90)Sr mobile forms in neutral soils will be observed in the next 10-20 yr. However, the difference between the maximum level of mobile forms contents and their existing contents will not exceed 20%.  相似文献   

17.
The contamination of groundwater in Bangladesh by arsenic is a widespread and serious environmental problem, affecting mainly the rural population who rely extensively on groundwater for drinking and cooking. The study conducted survey work in a few affected villages of the Northwest region in Bangladesh. The household survey gathered information on the respondents (affected by arsenic) water usage and sources, knowledge of the arsenic problem, changes in the source of water for drinking and cooking, arsenic mitigation technologies and socio-economic information on the households. The survey work shows that percentage of male patient is higher than female patient among the same level of household income in each study villages. Prevalence of arsenicosis is more among poorer sections and it is directly related to the poverty situation of the community. People know more about the health problems caused by arsenicosis but lack knowledge about mitigation aspects. In one of the study areas, every year an extra 4% tubewell is getting contaminated by arsenic. Arsenic contamination in groundwater also affects the environment and the ecology negatively. The NGOs have been found contributing to a knowledge creation process in the village community as the villagers are showing marked behavioral changes in water-use practice.
Nurun NaharEmail:
  相似文献   

18.
提高水资源使用效率是落实最严格水资源管理制度和水生态文明建设的重要内容。长江经济带是我国重要经济和生态走廊,也是我国正大力打造的经济新支撑带,分析各省会城市用水效率对缓解人水矛盾,促进水生态文明城市建设,推动长江经济带发展具有重大意义。基于2011-2013年长江经济带11个省会城市面板数据,利用超效率DEA模型和Malmquist指数测度各城市用水效率,并用Tobit模型检验其影响因素。①超效率DEA分析结果显示,长江经济带11个省会城市的水资源利用效率总体情况较好。分城市看,武汉、昆明、杭州、贵阳和成都水资源利用效率相对较高,上海和重庆水资源利用效率相对较低。2012年最严格水资源管理制度的实行,证明水资源利用效率受政策因素驱动迹象明显。②Malmquist指数分析结果显示,长江经济带11个省会城市整体水资源利用效率呈衰退趋势;而较低的技术效率变化和纯技术效率是制约长江经济带整体水资源利用效率的关键因素。省会城市中,杭州、合肥、长沙和贵阳TFP值排名靠前,长沙、上海、南昌和杭州技术进步最快;武汉用水效率衰退趋势最为明显和严重,合肥、长沙、杭州的用水效率提升较快。③Tobit回归结果表明,人均GDP、人均水资源量和第三产业比重对水资源利用效率影响较大且呈正相关关系。因此,从以上研究结果可以得出提升水资源利用效率的关键是在切实落实最严格水资源管理制度基础上,积极改进生产技术,普及节水工艺,大力发展第三产业,优化产业结构,最终形成制度、技术和结构的综合节水模式。  相似文献   

19.
Fluxes of dissolved organic matter (DOM) in larch biogeocenoses and its export from the drainage basin have been studied in the zone of continuous permafrost. A comparative assessment of DOM input into the soil has been made on slopes of northern and southern exposures (as variants reflecting the current state and warming). The dynamics of DOM export in a creek depending on the increasing depth of the active soil horizon in the drainage area have been revealed. It is concluded that an increase in the depth of the seasonally thawing layer induced by global warming will not have any significant effect on the amount of annual DOM export. Reduction of DOM export may be expected upon a decrease in litter stocks under the effect of their mineralization and forest fires.  相似文献   

20.
Previous work has demonstrated that plant uptake of radiocaesium (RCs) is related to the activity concentration of RCs in soil solution, which is linked to the soil/soil solution distribution coefficient, K(D). The solid-liquid distribution of RCs is generally studied in soil suspensions in the laboratory and there are few reported measurements for in situ soil solutions. From a data set of 53 different soils (contaminated with either 134CsCl or 137CsCl) used in pot trials to investigate grass uptake of RCs, we analysed the variation of in situ K(D) with measured soil properties. The soils differed widely in % clay (0.5-58%), organic matter content (1.9-96%) and pH (2.4-7.0, CaCl2). The K(D) varied between 29 and 375,000 L kg-' (median 1460 L kg(-1)). Stepwise multiple regression analysis showed a significant correlation between the log K(D) and pH (p < 0.001), log %clay (p < 0.01) and log exchangeable K (p < 0.001) (overall R2 = 0.70). The in situ K(D) values were further compared to K(D)S predicted using an existing model, which assumes that RCs sorption occurs on specific sites and regular ion-exchange sites on the soil solid phase. Sorption of RCs on specific sites was quantified from the radiocaesium interception potential (RIP) measured for each soil and the soil solution concentrations of K+ and NH4+. The in situ log K(D) correlated well with the predicted K(D) (R2 = 0.85 before plant growth, R2 = 0.83 after plant growth). However, the observations were fivefold to eightfold higher than the predictions, particularly for the mineral soils. We attribute the under-prediction to the long contact times (minimum 4 weeks) between the RCs tracers and our experimental soils relative to the short (24 h) contact times used in RIP measurements. We conclude that our data confirmed the model but that ageing of RCs in soil is a factor that needs to be considered to better predict in situ KD values.  相似文献   

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