Perceptions toward stewardship among residents living near U.S. Department of Energy Nuclear Facilities

Although stewardship has been widely defined and used in environmental management and planning, there is a dearth of studies that describe how the lay public perceives this concept. A national sample of residents in 14 states who live near DOE nuclear facilities were interviewed to delineate public understanding and awareness of the stewardship program of the U.S. Department of Energy (DOE). This study discusses the findings of the survey and discusses how institutional trust influences public participation and resident’s choices of potential stewards. Almost 40% of the respondents could not define stewardship; those who did, believed that ‘responsibility,’ ‘management,’ and ‘accountability’ are key elements of stewardship. In addition, about a third of the respondents identified Federal groups and the DOE as potential stewards. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue     

我国内陆流域各类水体中天然放射性核素浓度

1985年～1989年由新疆、甘肃、青海、西藏、内蒙古、陕西、宁夏等省、自治区环境监测站(研究所)对内陆流域各类水体中U、Th、~(226)Ra、~(40)K浓度进行调查,由调查的29条内陆河、23个湖泊、15座水库、55处井泉和34个自来水的统计结果表明,流域内各水体中U和~(40)K浓度的平均值与同期调查的黄河水系同类水体的浓度相近,明显高于长江水系,与全国同类水体相比亦属偏高。Th和~(226)Ra的平均浓度与全国同类水体的浓度相近,甘、新内陆区浓度较低。调查发现,一些咸水湖、井水和自来水中U、~(226)Ra,或~(40)K浓度异常偏高。     

沉淀物和生物中U,Th和226Ra的联合测定

用放射化学法对U,Th,~(226)Ra等核素进行联合测定,国外已有不少报道,只是所用的分离方法和所测的介质不同而已。我国学者也做过一些这方面的工作。本工作建立了用三正辛胺-二甲苯萃取分离法对沉积物和生物样中U,Th和~(226)Ra的联合测定方法。 二、主要仪器与试剂     

CUMULATIVE IMPACTS OF LANDUSE ON WATER QUALITY IN A SOUTHERN APPALACHIAN WATERSHED1

ABSTRACT: Water quality variables were sampled over 109 weeks along Coweeta Creek, a fifth-order stream located in the Appalachian mountains of western North Carolina. The purpose of this study was to observe any changes in water quality, over a range of flow conditions, with concomitant downstream changes in the mix of landuses. Variables sampled include pH, HCO₃^2?, conductivity, NO₃^?_?-N, NH₄⁺-N, PO₄^3?-P, C1^?-, Na, K, Ca²⁺, Mg²⁺, SO₄^2?, 5iO₂, turbidity, temperature, dissolved oxygen, total and fecal coliform, and focal streptococcus. Landcover/landuse was interpreted from 1:20,000 aerial photographs and entered in a GIS, along with information on total and paved road length, building location and density, catchment boundaries, hydrography, and slope. Linear regressions were performed to relate basin and near-stream landscape variables to water quality. Consistent, cumulative, downstream changes in water quality variables were observed along Coweeta Creek, concomitant with downstream, human-caused changes in landuse. Furthermore, larger downstream changes in water quality variables were observed during stormflow when compared to baseflow, suggesting cumulative impacts due to landscape alteration under study conditions were much greater during storm events. Although most water quality regulations, legislation, and sampling are promulgated for baseflow conditions, this work indicates they should also consider the cumulative impacts of physical, chemical, and biological water quality during stormflow.     

Fe/Al改性膨润土对铬酸根的吸附性能研究

利用膨润土原矿提取了粒径小于2μm的膨润土胶体,经过钠质化处理后分别用聚羟基铁和聚羟基铝进行改性,然后用一次平衡法研究了改性膨润土对水体中铬酸根的吸附性能.结果表明,与原矿相比,改性膨润土对铬酸根的吸附量有了不同程度的提高,铁改性膨润土对铬酸根的吸附量大于铝改性者.CrO42-的吸附平衡浓度为0.5 mmol·L-1时,Mt-1(Fe)、Mt-2(Fe)和Mt-3(Al)对铬酸根的吸附量分别为271.0 mmol·kg-1、114.0 mmol·kg-1和16.1 mmol·kg-1.改性膨润土对铬酸根的吸附量随离子强度的增加而增大,随体系pH值的增加而减小.铬酸根在改性膨润土表面的吸附以专性吸附机制为主,静电吸附所占比例很小,一般不超过30%.这些研究结果可为开发新型水处理剂提供理论指导.     

U and Th in some brown coals of Serbia and Montenegro and their environmental impact

GOAL, SCOPE AND BACKGROUND: The objective of this paper is to determine and compare the concentrations of U and Th in soft to hard brown (lignite to sub-bituminous) coals of Serbia and Montenegro. It also presents comparison of the obtained data on U and Th concentrations with the published data on coals located in some other countries of the world. Almost the whole coal production of Serbia and Montenegro is used as feed coals for combustion in thermal power plants. METHODS: Channel samples from open pit and underground mines and core samples were collected for hard and soft brown coals. For the analysis the samples were decomposed using microwave technique. Obtained solutions containing U and Th were analyzed by inductively coupled plasma mass spectroscopy (ICP-MS) using NIST standards. RESULTS: Concentration of U from the investigated basins and the corresponding mine fields ranges within 0.60-70.10 mg/kg, 0.65-3.20 mg/kg, 0.95-6.59 mg/kg, 1.20-6.05 mg/kg, 0.80-6.66 mg/kg, 0.18-89.90 mg/kg, 0.19-4.14 mg/kg, and 0.28-3.52 mg/kg for the Kostolac, Kolubara, Krepoljin, Sjenica, Soko Banja, Bogovina East field, Senje-Resavica and Pljevlja basins, respectively. Concentration of Th ranges within 0.20-2.60 mg/kg, 0.84-6.57 mg/kg, 1.48-6.48 mg/kg, 0.12-2.71 mg/kg, 0.13-4.95 mg/kg, 0.14-3.48 mg/kg, 0.29-3.56 mg/kg, and 0.17-1.89 mg/kg for the Kostolac, Kolubara, Krepoljin, Sjenica, Soko Banja, Bogovina East field, Senje-Resavica and Pljevlja basins, respectively. DISCUSSION: Brown coal from Senje-Resavica, Kolubara, Kostolac and Pljevlja is characterized by low U concentration. Coals form the Krepoljin, Soko Banja and Sjenica basins have slightly higher U concentrations than the mentioned group. The highest concentration of U is characteristic for the coal from the Bogovina East field. Concentration of Th in coals from Serbia and Montenegro has proved to be low. Out of all investigated coal basins, only the coal from the Krepoljin and Kolubara basins has high concentration of Th. The hydrothermally altered rocks of the Timok dacite-andesite complex, representing the basement of the Bogovina basin, could be a potential source of U, especially at the bottom part of the Lower seam of the Bogovina East field. CONCLUSIONS: This study shows that brown coals in Serbia and Montenegro (soft to hard brown coals or lignite to sub-bituminous) contain low levels of U (5.30 mg/kg, average value and 2.10 mg/kg geometric mean value) and Th (1.80 mg/kg, average value and 1.12 mg/kg geometric mean value). There are some obvious differences in concentration of U and Th in coals from different basins in Serbia and Montenegro. The approximate value for U and Th release mainly from power plants was 644.33 t and 983.46 t, respectively within the period 1965-2000 for the studied mines in Serbia, and 23.76 t and 15.05 t for the Potrlica mine (Montenegro) within the period 1965-1997. RECOMMENDATIONS: The coals in Serbia and Montenegro show no identifiable unfavourable impact on the surrounding environment, due to low natural radioactive concentration of U and Th, but further investigations concerning human health should be performed. PERSPECTIVES: Preliminary research revealed that in some Serbian coals (and, particularly, parts of the coal seam) U and Th content are rather high. Such coals should be carefully studied, as well as U and Th concentrations in ash, fly ash, waste disposals, nearby soil and ground water. Further studies should include determination of the radioactivity of all these products, and estimation of possible health impact.     

腐殖酸修饰凹凸棒对U(Ⅵ)的吸附性能及机理

采用腐殖酸(HA)修饰凹凸棒(ATP)制备得到腐殖酸/凹凸棒(HA/ATP),用于去除废水中的U(Ⅵ).通过静态吸附实验,研究了溶液初始pH、投加量、吸附时间和初始浓度对吸附的影响,并用扫描电镜(SEM),X射线能谱图(EDS),傅里叶红外光谱仪(FITR)分析吸附机理.实验结果表明,去除率随时间的增大而增大,在120 min内可以达到平衡;吸附剂投加量越大,溶液pH =6左右时越有利于U(Ⅵ)的去除;HA/ATP能多次重复使用,且经过5次吸附解吸后对U(Ⅵ)的去除率仍能达到96％.吸附过程均符合Langmuir和Frendlich等温方程.较之准一级动力学,准二级动力学模型能更好地拟合实验数据.SEM-EDS、FITR分析结果表明,U(Ⅵ)被成功地吸附到了HA/ATP的表面,吸附机理为络合作用.     

Depth profile of ²³⁶U/²³⁸U in soil samples in La Palma, Canary Islands

The vertical distribution of the ²³⁶U/²³⁸U isotopic ratio was investigated in soil samples from three different locations on La Palma (one of the seven Canary Islands, Spain). Additionally the ²⁴⁰Pu/²³⁹Pu atomic ratio, as it is a well establish tool for the source identification, was determined. The radiochemical procedure consisted of a U separation step by extraction chromatography using UTEVA^® Resin (Eichrom Technologies, Inc.). Afterwards Pu was separated from Th and Np by anion exchange using Dowex 1x2 (Dow Chemical Co.). Furthermore a new chemical procedure with tandem columns to separate Pu and U from the matrix was tested. For the determination of the uranium and plutonium isotopes by alpha spectrometry thin sources were prepared by microprecipitation techniques. Additionally these fractions separated from the soil samples were measured by Accelerator Mass Spectrometry (AMS) to get information on the isotopic ratios ²³⁶U/²³⁸U, ²⁴⁰Pu/²³⁹Pu and ²³⁶U/²³⁹Pu, respectively. The ²³⁶U concentrations [atoms/g] in each surface layer (∼2 cm) were surprisingly high compared to deeper layers where values around two orders of magnitude smaller were found. Since the isotopic ratio ²⁴⁰Pu/²³⁹Pu indicated a global fallout signature we assume the same origin as the probable source for ²³⁶U. Our measured ²³⁶U/²³⁹Pu value of around 0.2 is within the expected range for this contamination source.     

碱激发胶凝材料及其固化Pb^2＋的试验研究

对碱激胶凝材料（碱-偏高岭土、碱-矿渣和碱-粉煤灰）与水-水泥体系固化Ph^2＋进行了试验研究,其中水-水泥体系为对比样。结果表明：对于相同稠度的碱激发胶凝材料,即使Pb^2＋含量达到2．4％,除了碱-粉煤灰的抗压强度略低外,其他都达到30MPa以上,满足填埋或做建筑基材的使用要求;与水泥相比,碱激发胶凝材料能显著降低重金属离子（Ph^2＋）浸出浓度,其规律性与其NH4交换容量大小的规律性一致,与其固化体的抗压强度的大小没有相关性。