华东部分铀矿区内大气和饮用水体放射性水平调查研究

通过对华东地区２１个铀矿区内居民居住环境大气中氡与其子体α潜能浓度的调查,居民居室外氡浓度均值范围为６．７３～１３２．Ｂｑ／ｍ＾３,氡子体α潜能浓度均值范围为１１．０～７８．８ｈＪ／ｍ＾３。居室内的平均氡浓度范围为１４．５～１８５．８Ｂｑ／ｍ＾３,氡子体α潜能浓度均值范围为１３．８～１０４．２ｎＪ／ｍ＾３;对居民饮用水源的取样分析表明,铀的均值范围为０．１２～１．６８μｇ／Ｌ,钍的均值范围为０．０２～０．４２μｇ／Ｌ,镭－－２２６的均值范围为０．９０～１２．１ｍＢｑ／Ｌ,与全国和当地的放射性天然本底水平比较接近,均属正常本底水平。     

某铀矿山退役分矿环境放射性现状调查

文章介绍了对我国南方某铀矿山退役分矿环境放射性现状的调查与研究。结果表明：在所有监测项目中,完全退役的1号分矿治理完全达标;而属于政策性停产的2号分矿,某些监测点空气中氡浓度、γ辐射和水体放射性水平均超过国家限值。此外,两个分矿土壤中天然放射性核索的含量都比对照点高。     

大连市区地表天然放射性水平调查

利用ARD型γ能谱仪对辽宁省大连市区地表天然放射性核素238U、232Th、40K含量进行了现场测量.调查结果显示,大连市区238U、232Th、40K比活度平均值分别为23.09 Bq/kg（范围值1.24~151.91 Bq/kg）、18.99 Bq/kg（范围值0.41~92.57 Bq/kg）、386.39 Bq/kg（范围值31.30~1095.50 Bq/kg）,均显著低于全国和世界的平均值.在测得的238U、232Th、40K含量基础上,计算了距地面1 m高处空气中γ辐射吸收剂量率、外照射指数、内照射指数和年有效剂量等参数,并据此对大连市区天然放射性水平进行了评价.空气中γ辐射吸收剂量率（Dr）平均值为39.04 nGy/h,远低于全国（81.5 nGy/h）和世界（80 nGy/h）平均水平.外照射指数、内照射指数平均值分别为0.23、0.12,均远小于国家对建筑材料外照射指数的限值1.年有效剂量为0.048 mSv,远低于世界年平均有效剂量（0.46 mSv）以及公众外照射年有效剂量（1.0 mSv）的限值.评价结果表明,大连市区地表天然放射性辐射处于安全的水平.     

上海地区饮用天然矿泉水放射性水平的调查与卫生学评价

利用上海地区80余口饮用天然矿泉水井的总α、总β和²²⁶镭等放射性指标的检出数据,分析了不同含水层矿泉水放射性水平分布特征,估算了各含水层矿泉水作为纯饮水饮用对居民身体的内照射影响。评价结果表明,上海地区矿泉水放射性水平处于正常环境本底范围,放射性指标检出值均低于《饮用天然矿泉水》国家标准的限值,长期饮用不会对人体健康造成危害。     

大渡河下游地区地下水放射性环境水平现状调查

通过对大渡河下游地区地下水放射性环境水平状况的调查,得出大渡河下游地区地下水环境放射性水平处于国家限值范围内,U含量在0．16μg·L^-1．74μgL^-1,Th含量水平极低,IKa在（1．016Bq-L^-10．031Bq·L^-1之间。通过分析,地下水水位的变化受河流水位变化影响较大。     

翡翠原石的放射性水平研究

为了准确掌握翡翠原石的放射性水平,消除公众对珠宝玉石存在放射性的疑虑,本文选取了3种翡翠原石的10件样品,利用高纯锗型(HPGe)低本底多道γ能谱仪测量了样品中天然放射性核素²²⁶Ra、²³²Th和⁴⁰K的比活度值.结果表明,样品中有关核素的比活度值低于或仅略高于仪器检测限,样品的内照指数(I_Ra)和外照指数(I_γ)均远远低于国家对建筑材料中放射性核素的限量规定,说明翡翠原石的放射性水平很低,与环境的天然本底相当,不存在所谓的放射性危害.     

白龙江下游涉核地区水的放射性环境水平现状调查

通过白龙江下游涉核地区水的放射性环境水平调查,得出白龙江下游涉核地区的区域内水中铀、镭浓度普遍较低。U含量在0.35～5.42μg/L,Th含量水平极低,Ra在0.36～1.32Bq/L之间。通过分析,水中铀、镭浓度的相关性不一致,可知道在某些河段的铀、镭平衡已经被破坏,成为偏镭系的铀、镭平衡。     

白龙江下游涉核地区的放射性环境水平现状调查

通过对白龙江下游涉核地区及周边地区的汽车能谱测量和地面伽玛能谱测量以及空气中的氡浓度的监测,得出区内各地层中的U、Th、K含量均符合当地各地层的特性,与当地本底基本一致,空气氡浓度范围为183.9~305.8 Bq/m3,均属正常,符合当地的天然放射性环境情况,对环境无任何影响。     

基于水资源生态足迹的浑河流域水资源利用评价

用水资源生态足迹模型计算浑河流域2005~2013年水资源生态足迹和水资源生态承载力,并基于各评价指标对浑河流域水资源利用情况进行评价。结果表明:2005~2013年浑河流域水资源生态足迹呈现不显著的下降趋势,水资源生态承载力呈现波动变化;流域一直处于水资源生态赤字状态,仅在2010年出现盈余;流域水资源生态足迹指数低于可持续发展足迹指数范围,但万元GDP水资源生态足迹持续下降。总体来看,流域水资源利用处于不可持续状态,但2010年后流域水资源利用效率明显提高,并向着可持续的方向发展。     

用收缩试验资料间接估算压力板试验中的体积含水量

土水特征曲线是表征非饱和土基本性质的重要曲线之一,一般由压力板试验测定。膨胀土试样在压力板试验中体积变化很大,且其体积变化值又不得而知,故只能得到其重力含水量与基质吸力的关系。本文建议用收缩试验资料来间接估算压力板试验中试样的体积含水量,从而可得到用体积含水量与基质吸力关系表达的土水特征曲线。     

膨胀土的强度与含水量的关系

膨胀土的强度与含水量密切相关。针对这问题进行了相应的试验研究。结果表明,膨胀土的含水量对其峰值强度、稳态强度都有着强烈影响,这对工程设计和工程安全检测非常重要。     

积雪水热迁移机理与模型研究进展

积雪是陆地水文循环以及大气过程的重要组成部分,它调节了陆地和大气之间的能量交换,对下垫面的能量收支平衡与水热迁移起重要作用。在介绍积雪特性参数确定方法及积雪水热运移规律的基础上,对国内外现有积雪模型进行了分类和总结,并指出未来在积雪特性参数化方案、数值模拟计算、尺度转换等方面还应进行更深入的研究。     

广西北海近岸海域4200a以来古盐度时间序列分析

全新世以来的环境演化历程及未来环境演化趋势是当今全球变化研究的热点。海水古盐度作为反映古环境的一个重要指标,在古环境反演中起着重要作用。基于广西北海近岸海域BBWZK8沉积柱的地球化学和年代学分析,运用ARIMA时间序列模型对沉积物中反映古盐度的重要地球化学指标——w(Sr)/w(Ba)比值的变化特征进行了拟合和预测。研究结果表明,ARIMA(1,1,0)模型可以较好地拟合4 200 a以来沉积物中w(Sr)/w(Ba)比值的演化规律,模型的拟合曲线与过去环境演化历程基本吻合,也与前人的研究成果有着较好的一致性;预测结果显示,在未来400 a中北海近岸海域沉积物中的w(Sr)/w(Ba)仍呈逐渐降低的趋势(即海水的盐度将持续增大),但相对于以往的变化幅度(过去1 200 a),其降低的趋势明显放缓,据此可推测在今后一段时间内,区域气候将保持缓慢干旱的态势。     

Hydrogeology of the Ordos Basin,China

The Ordos Basin is located in the east of NW China that is composed of different aquifer systems. Karst groundwater is stored in the Carmbrian-Ordovician carbonates along the margins of the basin. Fissured-pore water is present in the Cretaceous strata in the central-western basin and pore water is stored in the overlying Quaternary deposits discontinuously. The main origin of groundwater in the basin is direct or indirect infiltration of precipitation. Groundwater flows from recharge areas to adjacent local discharge areas. Besides evaporation and abstraction, groundwater feeds springs and rivers, such as the Yellow River and its tributaries. According to the karst aquifer lithologic structure, the features of karst development and circulation, the karst aquifer is divided into three structural and circulation patterns. Based on the control of Cretaceous sedimentary environment, lithologic structure, lithofacies, and palaeogeographic characteristics, the Cretaceous system is divided into the northern desert simple plateau aquifer system and the southern loess plateau aquifer system. PACKER was used to obtain temperature, hydrogeochemical and isotope data at specific depths. Groundwater circulation is studied using hydrodynamic fields, temperature fields, isotopes, hydrogeochemical data and numerical simulations. According to the result, it is divided into local, intermediate and regional systems.     

岩溶水动态,矿物饱和指数与水源地选择

在分析区域地下水动态特征的基础上，用化学热力学方法计算出每个钻孔岩溶水的碳酸盐岩矿物饱和指数，结合二者之间的关系，找到了富水分布规律。通过勘探证实，在碳酸盐岩分布区，供水水源地应选择在地下水动态变化不大、滞后期不长、碳酸盐岩矿物馆和指数βｃ＞１～βｄ＜１的灰岩浅埋区。     

Groundwater quality assessment in parts of Eastern Niger Delta, Nigeria

Hydrogeochemical analyses were carried out on groundwater samples collected from 20 producing wells in different parts of the Eastern Niger Delta. Results show that the concentrations of the major cations (Na⁺, K⁺, Ca²⁺, Mg²⁺) and anions (Cl^–, SO ₄ ^2– , HCO ₃ ^– ) are below the World Health Organization (WHO) standards set for domestic purposes. The occurrence of slightly saline water in certain areas is attributed to local hydrogeological processes occurring in the area. On the basis of the analytical results, two hydrogeochemical facies are delineated. These are calcium-magnesium-chloride-sulfate-bicarbonate (Ca-Mg-Cl-SO₄-HCO₃) and calcium-sodium-chloride-sulfatebicarbonate (Ca-Na-Cl-SO₄-HCO₃) to the west and east of the study area, respectively.     

Diagnosis of trace Pb in domestic wells,Upper Gloucester Catchment,Maine, USA

Dissolved Pb in 32 wells associated with corroding submersible pumps is examined within a rural water district after almost 20 years (1984–2002). Groundwater Pb ranged from 0.4–24.9 μg L⁻¹ after 24 h pump flushing. Preliminary geochemistry and representative borehole lithology examinations were extrapolated by Markov chain modeling. The first-order geostatistical realizations of glacial sediments coupled with the Monte Carlo Metropolis-Hasting method suggest that elevated trace Pb persists in sand and gravel units, and continues at least to 40 m depth in the catchment. The ²⁰⁷Pb/²⁰⁶Pb and ²⁰⁸Pb/²⁰⁶Pb isotope compositions of groundwater Pb were decisive in discriminating the importance of leached Pb from submersible pump materials among geogenic sources.     

Chemistry of springwater in Almora, Central Himalaya, India

 A field study was conducted to assess variations in physico-chemical characteristics of water of the springs located within the boundary of a Central Himalayan town where the springwater is used for drinking purposes. Monitoring of 12 springs was carried out for three seasons (winter, summer and monsoon). The results indicate direct influence of unplanned sewage disposal on the springwater quality as reflected by significant regional variations in the concentration of nitrates, chlorides, sulfates, sulfides and electrical conductivity. Population density varies within the town from 3110 to 14 137 persons/km^–2 and has direct relationship with water quality. Springs located in the densely populated area had higher concentrations of all these compounds. Concentrations of nitrates up to 60 ppm were observed in some springs, making water unsuitable for human consumption. No significant changes were observed in springwater quality during different seasons. Received: 3 February 1995 · Accepted: 27 February 1996