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1.
Data on content of (90)Sr, (137)Cs, (239,240)Pu and (3)H in water of the Tobol-Irtysh part of the Techa-Iset-Tobol-Irtysh-Ob river system (through which the "Mayak" PA radioactive wastes are transported) are presented and discussed. The data were received in 2004-2005 under the ISTC project on radioecological monitoring of the Tobol and Irtysh rivers. Monthly observations of (137)Cs, (90)Sr and (3)H content in water in the area of the Tobol and Irtysh confluence have been conducted starting from May 2004. To obtain information on the investigated river system as a whole, the radioecological survey of the Tobol and Irtysh rivers at the section from the mouth of the Iset River to the confluence with the Ob River was carried out in 2004. It is shown that the impact of "Mayak" PA waste transport by (90)Sr is distinctly traced as far as the area of the Irtysh and Ob confluence.  相似文献   

2.
The Royal Decree of 20th July has entrusted the Federal Agency for Nuclear Control (FANC) with the task of controlling the territorial radioactivity and the doses received by the population. Within this agenda, a monitoring programme has been developed over many years, in order to follow the main potential exposure pathways of the population. In practice, several potential vectors of contamination are controlled: air (and rain), surface water (including sediments and biota), soils around nuclear installations, food chain, drinking water etc. To carry out such work, the FANC has collaborated with public or private reputable organisations: The Centre of Nuclear Energy Studies of Mol, The National Institute of Radionuclides of Fleurus, and The Louis Pasteur Public Health Institute of Brussels. A synthesis of this monitoring programme will be presented and the most important deductions will be pointed out. For many years, the tendency has been for tighter control of artificial and natural radioactivity in the environment. This has been achieved by increasingly stringent regulations, regarding environmental monitoring efforts, from international organisations (EC, OSPAR, IAEA). In this context, the FANC in Belgium, is involved in a process that will lead to the adaptation of the Belgian monitoring programme. Different aspects of these adaptations and of their consequences will be presented for illustrative purposes.  相似文献   

3.
Four areas of the Venice lagoon, placed near the Malamocco mouth (Alberoni, st. A), in the Lido watershed (Sacca Sessola, st. B) and near the mainland under the influence of freshwater and urban (San Giuliano, st. C) or industrial (Fusina, st. D) effluents were monitored in two periods: 1989-92 and 1998-99 in order to quantify some environmental changes (macroalgal and phytoplankton biomass, nutrient concentrations, physico-chemical variables) occurred in both the water column and the surface sediment over the '90s. Stations B and C, two areas particularly affected by macroalgae exhibited a biomass of ca. 20 and 8 kg WW m(-2), respectively, during 1989-90. In 1998-99 maximum densities decreased to ca. 0.3 and 0.01 kg WW m(-2). During that period, phytoplankton also decreased significantly both in peaks (Chl a: from 58-86 to 4.0-3.5 microg dm(-3)) and mean values (Chl a: from 9.1-10.3 to 1.3-1.4 microg dm(-3)), especially at sts. C and D. As far as nutrient concentrations are concerned, a different trend was observed in the water column and in the surface sediment, mainly because of the reduction of the primary producers and the disappearance of anoxic crises. In 1998-99 reactive phosphorus (RP) in the water column was up to ca. 3 times as high as in 1989-92. Conversely, dissolved inorganic nitrogen (DIN) was not significantly changed. In 1998-99 the 5 cm sediment top layer at sts. B, C, displayed a significant total nitrogen (TN) and total phosphorus (TP) decrease (TN annual mean: from 1.29 and 2.79 mg DW g(-1) to 0.69 and 1.47 mg DW g(-1), respectively; TP: from 401 and 626 microg DW g(-1) to 360 and 455 microg DW g(-1)). A different result was found at st. A which in 1998-99 was colonised by the seagrass Zostera marina L. That station showed a TN sediment increase from 0.25 to 0.67 mg DW g(-1) and a TP decrease from 455 to 350 microg DW g(-1). Station D, which did not show any macrophyte biomass coverage either in 1992-93 or in 1998-99, exhibited negligible differences. Besides the monitoring of biomasses and nutrients, significant changes related to oxygen concentration, water transparency, pH and E(h) and sediment rates were also recorded.  相似文献   

4.
Studies on the radiation level and the radionuclide distribution of some naturally occurring radioactive materials (NORM) in the soils of the coastal areas of Southern Nigeria were undertaken. The purpose of this study is to provide baseline data for the effective monitoring of unforeseeable radioactive fallout in these areas where a lot of oil exploration activities are going on. The radioactivity concentrations of these naturally occurring radionuclides (specifically (40)K, (238)U and (232)Th) in the soil samples were analyzed using a high-resolution, low-background, hyper-pure coaxial gamma-ray detector (EG&G ORTEC HPGe) coupled to an amplifier and multi-channel analyzer. The activity of (40)K ranges between 111.9 and 444.7 kBq kg(-1) with a median value of 283.28 kBq kg(-1); the activity of (226)Ra (a daughter of (238)U) varies from 23.24 to 43.66 kBq kg(-1) with a median value of 34.54 kBq kg(-1); and that of (232)Th ranges from 6.45 to 12.79 kBq kg(-1) with a median value of 9.17 kBq kg(-1). The mean absorbed dose rate in air due to these NORM is found to be (33.655+/-3.409) nGy h(-1). The correlation analyses showed a positive relationship between the three radionuclides in all the five coastal states.  相似文献   

5.
A river ecosystem in East Java, Indonesia, fed by a volcanic lake with high concentrations of dissolved metals and a low pH, was found to support only few macroinvertebrates. To unravel the causes of toxicity and to determine the level of dilution necessary to obtain non-toxic water, a bioassay was conducted with the fairy shrimp Thamnocephalus platyurus. A partial toxicity identification evaluation (TIE) approach was used with EDTA as a chelating agent to relate toxicity to pH and metal concentrations. Three water samples were tested, with pHs ranging from 0.72 to 4.5, and diluted with water from a neutral river to different degrees. The dilution factor necessary to achieve no more than 50% mortality in the Thamnotox test (Ldf(50)) varied from >300 at the most acidic site, to 7 for water of pH 2.6 and 1.5 for water of pH 4.5. Toxicity was best explained from both low pH and high concentrations of metals, especially Al and Fe. The key role of Al and Fe in the toxicity was confirmed by relating concentrations of the different compounds in the river water to toxicity data from the literature. EDTA addition did not significantly influence Ldf(50) or the lethal pH 50% (LpH(50)), suggesting a large effect, besides cationic components and pH, of anions (F, SO(4) and Cl).  相似文献   

6.
Five bivalve species--Mytilus galloprovinciallis (Mediterranean mussels), Venus gallina (stripped venus), Modiola barbatus L. (bearded horse mussels), Pecten jacobeus (scallops) and Callista chione (hard clams)--were collected from seven areas in Aegean Sea, Greece, between August 2001 and January 2003 and analyzed for organotins (OTs). The concentrations (as geometric means) found were 17.1 ng g-1 for tributyltin (TBT), 18.8 ng g-1 for dibutytltin (DBT), 7.8 ng g-1 for monobutyltin (MBT) and 13.0 ng g-1 for triphenyltin (TPhT) (wet weight), which are at similar or lower levels than those reported worldwide. Studying OTs distribution between different bivalve species, lower concentrations were observed in mediterranean mussels, possibly due to their growth in water column (grown on sea net pens in mussel farms), in contrast to the free-ranging species, collected from fishing grounds. Concentrations of the OTs in the examined bivalves varied seasonally.  相似文献   

7.
The regional environmental radiological effects were assessed for the past 25-year operation of the Tokai Reprocessing Plant (TRP). The assessment was basically performed with the environmental radiological monitoring data around the TRP. For the environmental monitoring, various kinds of terrestrial and marine samples including air dust, surface soil, polished rice grain, leafy vegetable, milk, seawater, seabed sediments, fish, shellfish and seaweed were collected in the surrounding environment of the TRP. Radionuclides such as (3)H, (14)C, (90)Sr, (137)Cs and (239,240)Pu in the environmental samples were determined by radiochemical methods. However, they showed no significant short-term increase or long-term accumulation of radionuclides discharged from the TRP. Therefore, the public dose was evaluated using the mathematical models and the discharge data of radionuclides. The estimated annual effective dose for the public was about 0.1% of the annual effective dose limit recommended by the ICRP. The assessment showed that there were no significant radiological effects on the environment and the public due to the 25-year operation of the TRP.  相似文献   

8.
Since the reform and opening-up, the difference between the development of the west region and the other regions in China is increasing. In addition, the condition of the development of cities in west China needs amelioration. Developing conditions of the west provinces and its cities using economic barometers (e.g. gross domestic product (GDP) and per capita GDP) and urban population datum (e.g. urbanization level and city primary degree) have been analyzed in this article. Five indexes have been chosen to work on the development of the provinces, for example, the contribution degree of the increment in GDP, the contribution degree of the increment of per capita GDP, urbanization level, city primary degree, city primacy ratio. Conclusions are as follows. (1) The growth of the GDP and per capita GDP of the western provinces is in a poor way; moreover, it is not steady going. (2) The comparability among the characteristics of the urbanization level growth of the provinces is at a low level. (3) The urbanization levels of Inner Mongolia province and Sinkiang province are more-sensitive responders to the growth of per capita GDP, whereas those of Guangxi province and Tibet province are less-sensitive responders. (4) The urban population in most of the provinces are highly concentrated, which can be shown by city primary degrees and city primacy ratios. While working on these cities in west China, some earlier zone-organic cities are chosen as sample cities, and these cities are also analyzed using economic barometers and population datum. By analyzing the difference among the cities and comparing the research findings of Professor Zhou and the author, the following conclusions are made: (1) the growth of the GDP and per capita GDP of the cities are mostly not steady going; (2) the middle and big cities are more-sensitive responders to the growth of economy, whereas the small and mega cities are less-sensitive responders; (3) the sizes of southwest cities have a higher speed than those of northwest ones, and furthermore, the differences between them are still increasing.  相似文献   

9.
长江中游城市群城市土地利用效率空间溢出效应研究   总被引:2,自引:0,他引:2  
城市群城市土地利用效率是城市群城市土地要素有效配置、合理利用以及城市经营管理水平的综合体现。在使用DEA方法得到2003~2015年长江中游城市群28个城市土地利用效率并且分析其变化趋势以及空间关联性的基础上,构建SDM模型对长江中游城市群的城市土地利用效率空间溢出效应进行分析。研究结果表明:(1)2003~2015年长江中游城市群城市土地利用效率总体呈波动变化趋势。长江中游城市群城市土地利用效率存在空间负相关关系,城市土地利用效率具有空间异质性;(2)通过构建SDM模型分析表明,外商直接投资额以及人均地区生产总值是长江中游城市群城市土地利用效率的主要驱动因素;(3)长江中游城市群城市土地利用效率的空间溢出效应较弱,在一定程度上反映了长江中游城市群城市之间的空间相互作用较弱,经济联系还不够紧密。因此,长江中游城市群需要进一步构建城市合作机制,提高城市土地利用系统的整体性和联动性,推进区域经济协同发展。  相似文献   

10.
Removal of NOM in the different stages of the water treatment process   总被引:5,自引:0,他引:5  
Natural organic matter (NOM) is abundant in natural waters in Finland and in many ways affects the unit operations in water purification. In this study, the organic matter content in water in different stages of a full-scale treatment process over 1 year was measured. The full-scale treatment sequence, studied at the Rusko water treatment plant in Tampere, Finland, consisted of coagulation, flocculation, clarification by sedimentation or flotation, activated carbon (AC) filtration, and disinfection. High-performance size exclusion chromatography (HPSEC) was used for separation to determine changes in the humic substances content during the purification process. In addition, total organic carbon (TOC), KMnO4-number, and UV-absorbance at wavelength 254 nm (UV254) were measured. High molecular weight (HMW) matter was clearly easier to remove in coagulation and clarification than low molecular weight (LMW) matter. Furthermore, depending on the regeneration of the activated carbon filters, activated carbon filtration was effective to a degree but did not remove most of the lowest molecular weight compounds. Significant correlation was established among HPSEC, KMnO4, UV254 absorbance, and TOC. HPSEC proved to be a fast and relatively easy method to estimate NOM content in water and, in fact, gave more information than traditional methods on the type of NOM in a water sample. It also helped the process performance follow-up.  相似文献   

11.
Consideration is given to three mechanisms of the topography-modulated influence of solar radiation and terrain anisotropy on the vegetation. Variables in the equations describing these mechanisms take into account (1) doses of photosynthetically active radiation, (2) the thermal regime of slopes, and (3) anisotropy resulting from wind impact and interspecific competition. Approaches (1) and (2) single out southern and southwestern slopes, respectively, whereas in approach (3) slopes of any aspect can be found distinguished. Statistical analysis of correlations between the total coverage of vegetation layers and the topography of the terrain has shown that mechanisms (2) and (3) play a leading role in the study area.  相似文献   

12.
Studies on paleosols under an archaeological landmark of a rare type (a complex of kurgans with “whiskers”) dating from the Early Iron Age (the fourth century AD) have been performed in the steppe zone of the Transural Plateau. The size and shape of third-order soil polygons under stony ridges (“whiskers”) between the kurgans have been described in detail. The results have shown that the paleosol under the kurgans erected at the turn of the Late Sarmatian and Hun times (1600 years ago) is characterized by a higher humus content and deeper location of the carbonate horizon, compared to the recent soil. This indicates that an increase in atmospheric humidity took place in the fourth century AD.  相似文献   

13.
Being persistent, toxic, and bio-accumulative, Mercury (Hg) seriously affects the environment and human health. Due to Hg's attribute of long-range environmental transport across national borders, especially through atmospheric transport, no country can fully protect its environment and human health with its own efforts, without global cooperation. The Minamata Convention on Mercury, which was formally adopted and opened for signature in October 2013, is the only global environmental regime on the control of Hg pollution. Its main substantive control measures are source-specific: its phasing-out, phasing-down, and other main substantive requirements all direct to specific categories of pollution sources through the regulation of specific sectors of the economy and social life. This Convention does not take a national quota approach to quantify the Parties' nationwide total allowable consumption or discharge of Hg or Hg compounds, nor does it quantify their nationwide total reduction requirements. This paper attempts to find the underlying reasons for this source-specific approach and offers two interpretations. One possible interpretation is that Hg might be a non-threshold pollutant, i.e., a pollutant without a risk-free value of concentration. The existence of a reference dose (RfD), reference concentration (RfC), provisional tolerable weekly intake (PTWI), minimal risk level (MRL) or other similar reference values of Hg does not necessarily mean that Hg cannot be regarded as non-threshold because such reference values have scientific uncertainties and may also involve policy considerations. Another interpretation is that Hg lacks a feasibly determinable total allowable quantity. There is evidence that negotiators might have treated Hg as non-threshold, or at least accepted that Hg lacks a feasibly determinable total allowable quantity: (1) The negotiators were informed about the serious situations of the current emissions, releases, and legacy deposition; (2) the UNEP Secretariat took the position that Hg is non-threshold and should be eliminated to the maximum; (3) European countries, the USA and other western countries were in a better position to regard Hg as non-threshold and push forward a global reduction of Hg emissions and releases to the minimum; (4) the negotiators took the Stockholm Convention on Persistent Organic Pollutants (POPs) as a model; and (5) a fairly large number of non-governmental organizations (NGOs) were organized under umbrella NGO networks such as the Zero Mercury Working Group (ZMWG) and the International POPs Elimination Network (IPEN) and made a significant contribution to the negotiation process. The interpretations for the Minamata Convention might similarly be used to interpret the source-specific approach of the Stockholm Convention on POPs and the national quota approach of global environmental regimes on stratospheric ozone and climate mitigation. These two interpretations focus on the features of the pollutants and for this reason may be useful for future negotiators of other international environmental treaties to select appropriate models. They also suggest that the source-specific approach may be adopted in the future for pollutants with similar features of being possibly non-threshold and without a feasibly determinable total allowable quantity.  相似文献   

14.
The Holocene evolution of vegetation in the high-plain territory of the northwestern Volga Upland has been shown to have certain specific features. Based on analysis of spore–pollen assemblages from peat deposits, the onset of bog formation has been dated to the late Boreal period (about 8500 yr BP); the pine–birch phase in the development of forests, to the early Atlantic period (8000?6000 yr BP); the appearance and peak development of the zonal broadleaf species complex, to the late Atlantic period (6000?4500 yr BP); and early anthropogenic changes in the vegetation, to about 3000 yr BP.  相似文献   

15.
Changes in the altitudinal position of the timberline in high mountain areas of the Nether-Polar Urals and basic factors that influence such changes have been revealed on the basis of comparison of the age structure of Siberian larch (Larix sibirica) and arctic birch (Betula tortuosa) tree stands and photographs made in different years. On the mountain slopes studied, an upward shift of the timberline took place in areas covered in winter with thick snow (in the late 18th century), with Siberian larch being the pioneer species. Larch began colonizing areas with a thin snow cover in the 20th century. Birch appeared later and has since strengthened its positions. The increase in winter temperatures and precipitation facilitated the expansion of the forest.  相似文献   

16.
长江中游地区贫困村空间分异研究   总被引:1,自引:0,他引:1  
以长江中游地区的湖北省、湖南省以及江西省在十三五规划当中所涉及的贫困村为研究对象,采用核密度分析、最近邻指数以及空间自相关等空间统计法,对贫困村的数量、空间分布密度及模式、垂直梯度分异等特征进行了分析。结果表明:(1)长江中游地区贫困村省际分布有所不同。数量上湖南省>湖北省>江西省,并且同时存在典型的“平原型”贫困村和“山区型”贫困村,且在省域、国贫县、省贫县、非贫县、城市圈等多级尺度下的数量特征不同;(2)在城市群或者城市圈内,贫困村分布呈现低值集聚,而省域交界处的山区多为贫困村分布的高值集聚区;在巫山、雪峰山和武陵山的贫困连片分布区,贫困村多呈均匀型分布;在江汉平原地区,出现显著的集聚型分布;(3)贫困村的垂直空间分异显著。贫困村主要分布在海拔<200 m的平原地区,随着海拔的升高,数量不断减少。研究有利于更好地认知和理解长江中游地区的贫困村空间格局,实施更为科学的“精准扶贫”战略。  相似文献   

17.
Sea-level rise is a major threat facing the Coral Triangle countries in the twenty-first century. Assessments of vulnerability and adaptation that consider the interactions among natural and social systems are critical to identifying habitats and communities vulnerable to sea-level rise and for supporting the development of adaptation strategies. This paper presents such an assessment using the DIVA model and identifies vulnerable coastal regions and habitats in Coral Triangle countries at national and sub-national levels (administrative provinces). The following four main sea-level rise impacts are assessed in ecological, social and economic terms over the twenty-first century: (1) coastal wetland change, (2) increased coastal flooding, (3) increased coastal erosion, and (4) saltwater intrusion into estuaries and deltas. The results suggest that sea-level rise will significantly affect coastal regions and habitats in the Coral Triangle countries, but the impacts will differ across the region in terms of people flooded annually, coastal wetland change and loss, and damage and adaptation costs. Indonesia is projected to be most affected by coastal flooding, with nearly 5.9 million people expected to experience flooding annually in 2100 assuming no adaptation. However, if adaptation is considered, this number is significantly reduced. By the end of the century, coastal wetland loss is most significant for Indonesia in terms of total area lost, but the Solomon Islands are projected to experience the greatest relative loss of coastal wetlands. Damage costs associated with sea-level rise are highest in the Philippines (US $6.5 billion/year) and lowest in the Solomon Islands (US $70,000/year). Adaptation is estimated to reduce damage costs significantly, in particular for the Philippines, Indonesia, and Malaysia (between 68 and 99%). These results suggest that the impacts of sea-level rise are likely to be widespread in the region and adaptation measures must be broadly applied.  相似文献   

18.
A field study was carried out along the Golfe du Lion, that focussed on the beaches of the Camargue, to locate the main areas where enriched U and Th are found, and to better understand the processes that concentrate radioactivity on beaches. Indeed enriched areas are observed on some Camargue beaches, where high-dose rates are recorded due to excess U and Th activity (>1000 Bq kg(-1)). The coastline was mapped by means of an aerial gamma survey and the results indicated that the main actinides deposits occurred in the Camargue area. This concentrating effect is possibly due to a greater sedimentary contribution from the River Rhone relative to other minor Mediterranean rivers. Across the along-shore profile, the variability in actinides observed at the eastern part of Beauduc spit is mainly explained by variations in heavy and light mineral contents. Such variability can be accounted for by redistribution of the sand caused by erosion/deposition processes occurring in the eastern part of the spit. Further parameters such as grain size and heavy minerals content were studied in connection with the distribution of U, Th and (40)K in the field at a more localised level (i.e. across-shore beach profile). The <200-micro m fraction contains more than 50% of the radioactivity and heavy minerals (especially zircon) are the main contributors to the high levels of external radiation. Therefore the enriched areas, where U and Th exceed 1000 Bq kg(-1), presumably result from the sorting of sand grains according to their size and density.  相似文献   

19.
三峡水库蓄水后长江中游宜昌江段鱼类早期资源群聚动态   总被引:1,自引:0,他引:1  
基于2007~2018年葛洲坝下宜昌江段鱼类早期资源调查资料的整理分析,采用群落生态学方法对12年来长江中游鱼类早期资源群聚特性和年际变化趋势进行了研究,探讨了三峡水库蓄水后鱼类早期资源的优势种更替过程和群落结构变异.结果显示:12年间共采集到鱼卵5目9科49种,其中产漂流性卵鱼类28种.鱼卵物种数的年际变化趋势不显著,但年间变幅较大(18~30种/a).鱼卵丰度的年际变化表现出明显的趋势性上升,其中"四大家鱼"采集数量和密度呈先下降后上升的"U"型变化趋势.群落结构分析显示,12年间宜昌江段鱼卵物种多样性指数均呈缓慢下降趋势,并在2007~2008、2009~2013和2014~2018年形成三组不同的时间聚类,组间差异显著.SIMPER分析表明,各时期鱼卵群落差异主要受优势种和重要种所决定.2013年前,贝氏(鳖)(Hemiculter.bleekeri)、银鮑(Squalidus argentatus)、银鲴(Xerocypris macrolepis)、草鱼(Ctenopha-ryngodonidellus)等交替出现成为主要优势物种;2013年后,贝氏(鳖)成为主要优势物种,优势种和重要种的鱼卵数量占比进一步上升(大于90%).研究结果指出,2003年三峡水库蓄水后,葛洲坝下宜昌江段鱼类早期资源优势种更替现象逐渐消失,群落结构趋于稳定,繁殖鱼类群落结构正向"单一化"发展.  相似文献   

20.
浮游植物群落特征是水域生态系统的一个基础信息,三峡水库作为长江经济带环境保护的重要区域,而关于三峡水库全水域浮游植物群落特征及其影响因素的研究报道仍不多见。为了解三峡水库浮游植物群落特征差异及影响因素等一系列基础信息,于2015年4月对三峡水库进行了大范围的调查,调查范围包括17个长江断面(共51个样点)及22条支流库湾(共122个样点)。结果显示:共采集到浮游植物7门39属61种,以绿藻门、硅藻门、甲藻门为主,其中绿藻门有26种,占据总种数的42.62%;硅藻门有16种,占据总种数的26.23%;甲藻门有7种,占据总种数的11.48%。丰度方面,硅藻门占绝对优势,比例为34.26%,其次是隐藻门(23.72%)、蓝藻门(20.96%)。生物量方面,则是甲藻门占绝对优势,其比例达到了44.18%,随后是隐藻门(29.92%)、硅藻门(14.32%)。丰度和生物量分别变化在2.22×10~4~5.12×10~(7 )cells/L和0.001 8~120.99 mg/L之间,且存在一致的趋势,从三峡大坝往长江上游,丰度值和生物量值逐渐增加。支流库湾浮游植物Shannon-Wiener多样性指数显著高于长江干流(Mann-Whitney U检验,P0.001)。冗余分析(Redundancy Analysis,RDA)表明,在长江干流中,水温(WT)、可溶性硅酸盐(DSi)是影响浮游植物群落结构的主要环境因子(P0.001);在支流库湾中,硝态氮(NO~-_3-N)、水温(WT)是影响浮游植物群落结构的主要环境因子(P=0.002)。该研究的成果有助于全面认识了解三峡水库长江干流和支流库湾春季浮游植物种类组成和影响因子,同时对三峡水库水资源管理和水生态保护具有一定参考价值。  相似文献   

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