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The pathway by which "Co and 137C3 got into Area, and the type of uptake in animal were studied. The results showed that 60Co was taken up by gill and was transferred quickly to other organs through blood. There are more uptake pathways for 137Cs. The uptake of 60Co by Arca was mainly active transfer and the energy comes mainly from the process of biotic oxidation. On the contrary, the uptake of 137C3 by Arca was mainly a passive transfer, and for most organs the exchange through body-wall was a significant factor. 相似文献
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The transfer of 137C3, 60Co along Platymonas sp., Brachionus plieatilis Muller and Tilapia mos-sambica Peters was studied by using the tracer methods of both 137C3 and 60Co with Ge (Li) Gamma ray detector and S-80 type multichannel-analyser for measuring the radioactivity of the sample. The experiment was carried out in four groups and the period of the experiment was fifteen days. It was found that 60Co could be transferred along seawater→Platymonas→Brackionus→Tilapia, and that 137C3 could only be transferred from seawater to Platymonas. 137C3 was not accumulated by Brachionus in any group of the experiment. Brachionus ingested 60Co mainly from Platymonas, when 60Co was ingested by Tilapia; Brachionus played an important role in the transfer and the Tilapia ingested 137C3 mainly from seawater. 相似文献
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As part of a broad research program on the behavior of critical radionuclides to be discharged into the sea by the first Brazilian nuclear powerplant, the uptake accumulation and loss of 137Cs, 60Co and 125I by locally abundant seaweed species was studiedUptake in static 12 liter aquarium experiments reached apparent steady-state in 2–7 days (60Co and 125I) or 2–3 weeks (137Cs). Elimination followed a reverse pattern, being comparatively fast for 137Cs and slow for 60Co and 125I. Dry weight bioaccumulation factors (BFs) were variable, falling in the 101 range for 137Cs, 103 for 125I and 103–104 for 60Co. Various short-term experiments performed over a 16 month period, showed marked temporal variations of 60Co BFs for all species.The results demonstrated that the studied species may play an important role in the transfer of the critical radionuclides through local food webs and can be employed as useful monitors for routine or accidental radionuclide releases. 相似文献
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The effects of three photoperiods (24 hr illumination, 12 hr illumination + 12 hr darkness and 24 hr darkness) and three salinities (20‰, 30‰ and 35‰) on the uptake of 60Co and 137Cs for Chlorella sp. and on the growth of its algae are studied. The uptake of 60Co for the algae is two orders of magnitude higher than that of 137Cs. Of factorial effects, the effect of photoperiod is most significant either on the uptake of the radionuclides or on the growth of the algae; the effect of salinity comes next in order and that of their interaction remains with the last. The uptake of the two radionuclides increases with extended photoperiod while the uptake of 137Cs declines with increasing of salinity. The growth of the algae appears to be the best under the conditions of 24 hr illumination and 30‰ salinity. 相似文献
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历次核试验进入海洋的~(137)Cs对中国近海影响的模拟研究 总被引：1，自引：0，他引：1
1945年以来,世界各主要核国家进行了数千次核试验,这些核试验产生的绝大部分放射性物质通过多种途径进入海洋,对海洋环境造成放射性污染。本文建立了一个准全球海洋的放射性物质输运和扩散数值模式,通过数值模拟手段评估了历史核试验释放的放射性物质137 Cs对中国近海海洋环境的影响。本文借助前人工作评估了核试验释放137Cs进入海洋的途径和总量;通过比较模拟结果与观测资料,表明本文建立的放射性物质模式能够较好地模拟出137Cs在中国近海及其邻近海域的分布情况和随时间演变特征;模拟结果表明中国近海里的137Cs浓度在20世纪50年代中期达到最大,其中吕宋海峡海域137Cs浓度最高,达80.99Bq/m3;进一步分析了2011年3月份日本福岛核事故前中国近海137Cs浓度分布状况,2011年整个中国近海137Cs浓度介于1.0~1.6Bq/m3间,且其浓度垂向分布较均匀,相对封闭的南海浓度略高于其他海域。 相似文献
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D.S. Swan M.S. Baxter I.G. McKinley W. Jack 《Estuarine, Coastal and Shelf Science》1982,15(5):515-536
Analysis of 210Pb, 226Ra, 137Cs and 134Cs in short sediment cores provide first estimates of deposition rates in some Clyde sea lochs. The radio-caesium nuclides originate mainly in the liquid effluent released at distance from the Clyde by the Windscale nuclear fuel reprocessing plant and their concentrations in Clyde sediments provide information on (a) enrichment factors onto particulate matter, (b) surficial mixing coefficients and (c) sedimentation rates. A radiocaesium residence time in coastal waters of ca. 103 years reflects the importance of scavenging by the high nearshore particulate flux. 210Pb levels in sediments are controlled, in the unsupported fraction, by a major input sorbed on catchment particulates and, in the supported component, by 226Ra activities occasionally perturbed by unusually high surface values probably of planktonic origin. In one loch, detectable levels of 134Cs and 60Co are attributed to their discharge by nuclear submarines. 相似文献
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A novel approach to in situ extraction of Cs radionuclides from seawater is described which offers many advantages over previous methods. Cesium (stable and radioactive) is partially stripped from seawater as it passes in series through a tandem cartridge consisting of twin beds of ion exchange resin impregnated with cupric ferrocyanide. It is demonstrated that, when seawater passes through this cartridge at a constant flow-rate, collection efficiencies of each bed are the same, allowing the calculation of the seawater Cs nuclide concentration. The cartridge is made of inexpensive, readily available, PVC pipe fittings and is easily deployed under various field conditions. Procedures are described for resin preparation and desorption and radiochemical purification of the collected Cs. Thousands of liters of seawater can be stripped of Cs in this way, permitting substantial improvement in the sensitivity of measurement of 134Cs and 137Cs. 相似文献
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本文报道2015年9月和2016年5月期间天然放射性核素224Ra和223Ra在吕宋海峡及周边海域表层和垂向水体的分布特征。为理解日本福岛核事故的影响，本文亦分析研究区域内人工放射性核素137Cs的分布特征。结果表明，224，223Ra和137Cs比活度水平均处于我国南海海洋天然放射性本底变化范围之内。224Ra在吕宋海峡以西南海北部海域比活度较高，在吕宋海峡以东菲律宾海域比活度较低。137Cs没有明显的分布趋势。基于三站位（LS3，LS5和LS8）224Ra、137Cs以及温盐的垂向分布特征，本文揭示224Ra和137Cs在热带表层水、次表层水和中-深层水中比活度水平和梯度变化的差异特征。彩虹台风事件扭转了整个吕宋海峡及周边海域的海流循环过程。大量以低水平224Ra为特征的西太平洋海水涌入南海，降低水体224Ra比活度水平。但是，西太平洋和南海北部海域水体137Cs比活度水平没有明显差异，台风导致的海流变化对水体137Cs比活度没有明显影响。 相似文献
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几种近海沉积物吸附137Cs的初步研究 总被引：1，自引：0，他引：1
在对青岛近海放射性污染调查研究中发现,该海区与对照海区(石岛海区和连云港海区)海水中~(137)Cs的含量处于同一水平,而所取沉积物中~(l37)Cs的含量却存在明显差异。同 相似文献
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Contents of90Sr,137Cs and60Co in surface sediments were investigated in and around Urazoko Bay, Fukui Prefecture, where a nuclear power plant has been operating since 1969 and the waste effluent has been released into the sea. The main source of90Sr and137Cs was recognized to be radioactive fallout, whereas60Co was considered to originate from the nuclear power plant. Using the137Cs concentration as an indicator of sorption capacity of the sediment, the behaviour of60Co was investigated. No seasonal variation was observed in the distribution pattern of60Co/137Cs ratio and the retention of the heavy initial discharge in 1969 was considered to dominate the radionuclide level in the sediment. Correlation of60Co/137Cs ratio in the sediment and the distance from the discharge outlet was expressed by a simple exponential function of the distance. It was suggested that the contamination is spreading out gradually to the outer region of Urazoko Bay. 相似文献
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The Fukushima nuclear accident in 2011 released large amounts of radionuclides, including ~(137)Cs, into the Pacific Ocean. A quasi-global ocean radioactive transport model with horizontal grid spacing of 0.5°×0.5° and 21 vertical layers was thereafter established to study the long-term transport of the Fukushima-derived ~(137)Cs in the ocean.The simulation shows that the plume of ~(137)Cs would be rapidly transported eastward alongside the Kuroshio Current and its extensions. Contaminated waters with concentrations lower than 2 Bq/m3 would reach the west coast of North America 4 or 5 years after the accident. The ~(137)Cs tends to be carried, despite its very low concentration, into the Indian and South Pacific Oceans by 2016 via various branches of ocean currents.Meanwhile, the ~(137)Cs concentrations in the western part of the North Pacific Ocean decrease rapidly with time. Up to now the highly contaminated waters have remained in the upper 400 m, showing no evidence of significant penetration to deeper layers. 相似文献
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对赣北黄茅潭近代湖泊沉积岩芯进行了~(137)Cs、~(210)Pb测试和SCP(球状碳粒)计数分析,阐述了~(137)Cs蓄积特征,结合SCP计数、粒度指标及降水记录厘定了一些事件性沉积层位。研究表明,1986年前后是沉积环境中~(137)Cs行为的转折点;在这之前,~(137)Cs以大气散落为主,其蓄积行为大致与降水存在正相关关系,在这之后,~(137)Cs以流域侵蚀为主,其蓄积行为与降水呈负相关关系。1953—1954年、1974—1975年、1998—1999年,流域降水丰沛,相应沉积层位~(137)Cs比活度低,这与流域强烈侵蚀稀释了进入湖泊的~(137)Cs有关。1963—1964年沉积层位~(137)Cs蓄积峰稳定而显著,与高通量的大气散落有关,也与当时降水量低,大雨、暴雨次数少,流域侵蚀强度低造成较低的沉积速率等密切相关,是可靠的定年时标。1986年存在同样的气候环境特点,其蓄积峰可能也是存在的,但需要进一步确认。基于~(210)Pb方法,利用多种计年模式计算了沉积岩芯的年代,发现与这些事件性沉积层位具有较大差异。研究认为,在长江中游这种降水高、流域侵蚀强度高的较为复杂的沉积环境中,~(210)Pb计年存在较大误差。复杂沉积环境中近代沉积的定年,有必要深度挖掘~(137)Cs环境行为,在全面阐述其蓄积特点的基础上,辅以SCP计数、粒度指标及降水等识别事件性沉积层位,矫正~(210)Pb计年,是精确建立近代沉积时标的必要方法。 相似文献
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采用超低本底液闪β计数的方法,测定了春季黄海、东海海水中溶解态、悬浮物、筛绢颗粒物和雨水中天然32P和33P的比活度.结果显示,上层海水各相33P,32P的比活度相当低,其中TDP的32P,33P比活度的浓度最高,悬浮物次之,筛绢颗粒物最低.海水各相中33P与32P活度比值从TDP到悬浮物、筛绢颗粒物逐渐增大,反映出食物链传递过程中磷的年龄逐渐增加.根据稳态模式的估算结果,海水各相中磷的停留时间具有明显的区域变化特征,其中近岸和内陆架溶解磷的停留时间比外陆架短,仅为3~4 d,意味着近岸和内陆架海区低浓度的磷也可能维持高生物生产力的运转.利用稳态模式还估算出浮游植物的碳同化通量为189~814 mg/(m2·d),浮游动物的碳摄食通量为10~161 mg/(m2·d).此外,通过比较雨水32P,33P的输入通量和海水32P,33P积存量,利用质量平衡方法估算出上层海水POC输出通量为102~972 mg/(m2·d). 相似文献
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According to the principle of photosythesis with sunlight and CO2 by phytoplankton supplying food for marine organisms, while the nitrogenous compounds excreted by marine animals are transferred by bacteria into the nitrate for the use of phytoplankton, an artificial microhabitat is built to investigate comprehensively distributive relationship of 127Cs, 134Cs, 65Zn, 60Co, 50Fe, 54Mn In the parts of the microhabitat. The results show that 78% of the 134Cs and 137Cs in ion state are present in sea water, with 28 % of them nearly homogenous envolved in the exchanging processes of the suspensates and organisms, and that 80% of 59Fe, 54Mn, 65Zn, 60Co were concentrated by solid substance, whose motion was mainly controlled by biological processes. The factors affecting the distribution of nuclides in each composition are discussed. As another type of research on the controlled ecological system which is a subject currently studied in the world, the present paper is of reference value for studying quantitativ 相似文献
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本文从地球化学和环境保护的角度,用8180—4Kγ谱仪直接测定方法确定了天然放射性元素U,Ra,Th,~(40)K,及人工核素~(137)Cs的含量,讨论了它们的分布特点及其影响因素,指出了河口区与下游段元素变化的差异及其制约条件。 相似文献
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Arrigo A. Cigna 《Ocean Science Journal》2006,41(4):261-290
The concentrations of man made radionuclides in surface seawater since early ′60s are here reported as measured in Italy and
Japan. Most of the data refers to90Sr and137Cs, but occasionally the concentrations of89Sr and134Cs in some Italian samples are also given. The main sources of man made radionuclides were the global fallout produced by
the nuclear weapon tests and the Chernobyl accident. The respective contributions to the contamination of surface seawater
around both countries are discussed. 相似文献