中国大陆含油气盆地的氦同位素组成及大地热流密度

根据天然气中氦同位素组成,讨论了中国大陆主要含油气盆地氦同位素地球化学特征与大地热流密度。不同地区425个~3He/~4He 值表明中国含油气盆地天然气的氦同位素组成变化范围较大,为4.0×10~(-9)-7.21×10~(-6),在统计直方图上呈现三个峰值:1.5×10~(-8),3.0×10~(-7)和1.5×10~(-6)。中国东部大陆裂谷系中、新生代盆地内天然气的~3He/~4He 值分布范围为1.02×10~(-7)-7.21×10~(-6),50%以上大于大气的值(1.4×10~(-6));其他地区含油气盆地天然气的~3He/~4He 值分布范围为4.0×10~(-9)-7.01×10~(-7),全部小于大气的~3He/~4He 值。根据天然气中~3He/~4He 值计算的大地热流密度值分布在30-82mW/m~2 之间。利用~3He/~4He 值计算的大地热流密度值与用其他方法测得的值相一致,在中国大陆水平方向上呈现"东高西低"的变化趋势。     

苍山5.2级地震前临沂台深井地电异常

对苍山５．２级地震前距震中２３ｋｍ的临沂台深井地电观测资料进行了分析．结果表明,震前该台电阻率和自然电位出现了长达５年的与地震活动性异常同步的趋势异常．震前６个月电阻率出现下降异常．震前２４天自然电位和电阻率同时急剧下降,震后又同时急剧回升     

Victims from volcanic eruptions: a revised database

 The number of victims from volcanism and the primary cause(s) of death reported in the literature show considerable uncertainty. We present the results of investigations carried out either in contemporary accounts or in specific studies of eruptions that occurred since A.D. 1783. More than 220 000 people died because of volcanic activity during this period, which includes approximately 90% of the recorded deaths throughout history. Most of the fatalities resulted from post-eruption famine and epidemic disease (30.3%), nuées ardentes or pyroclastic flows and surges (26.8%), mudflows or lahars (17.1%), and volcanogenic tsunamis (16.9%). At present, however, international relief efforts might reduce the effects of post-eruption crop failure and disease, and at least some of the lahars could be anticipated in time by adequate scientific and social response. Thus, mitigation of hazards from pyroclastic flows and tsunamis will become of paramount importance to volcanologists and civil authorities. Received: 3 August 1997 / Accepted: 10 April 1998     

Mercury in lake sediments of the Precambrian Shield near Huntsville, Ontario, Canada

 Long sediment cores (>1 m) were collected from eight Precambrian Shield lakes in southern Ontario, Canada and analyzed for mercury (Hg), loss-on-ignition (LOI), and a suite of 36 other elements. Results indicated at least 100-fold variation in sediment Hg concentrations between lakes in close proximity (from 450 ppb), comparable to the variation reported for lakes across the whole of Canada. Strong areal correlations between Hg concentrations and LOI (r ² =0.77), between Hg and other trace element concentrations (Pb, Zn, Cd, Sb, As, Br), and similarities in the vertical concentration profiles of Hg and LOI, all point to the importance of organic matter in the release, transport and redistribution of metals in watershed systems. The spatial pattern of Hg concentrations in deep, precolonial sediments (>20 cm) was found to mirror the pattern of Hg concentrations in modern surface sediments, an observation that was confirmed in a follow-up survey (r ² =0.85;n=25 lakes), indicating that natural processes govern the unequal distribution of Hg among these lakes. Between-lake differences in surface sediment Hg concentrations normalized to organic carbon (Hg/C) were also reflected by Hg concentrations in smallmouth bass normalized to 35 cm length (R ² =0.63;n=15 lakes). The latter relationship suggests that smallmouth bass and lake sediment indicators provide mutually supportive information regarding Hg loading to the lacustrine environment from geological sources in the watershed system. Received: 31 October 1996 · Accepted: 27 May 1997     

Testing the ability of bentonite-amended natural zeolite (clinoptinolite) to remove heavy metals from liquid waste

 The design of environmentally sound liquid waste containment structures has become a crucial task in engineering applications due to ever increasing groundwater contamination from such sites. Construction of such structures usually requires a bottom liner of low hydraulic conductivity as part of the design. In order to reduce the hazards associated with liquid wastes including landfill leachate, bentonite-amended natural zeolite is proposed as an alternative to conventional earthen liners. Among many contaminants associated with liquid wastes, heavy metals are the most dangerous ones. This paper deals with determining the ability of natural zeolite to remove heavy metals from aqueous waste. For this purpose, crushed natural zeolite (clinoptinolite) is amended with commercial powdered bentonite to yield a soil mixture low in permeability and high in ion-exchange capacity. Leachate from a conventional landfill is used as the percolation fluid. Concentrations of certain heavy metals in the effluent fluid percolated through the bentonite-zeolite mixture are compared with that of initial leachate. The conclusion is reached that certain metals are efficiently removed from the influent solution by the soil matrix whereas some ions do not show significant reduction in concentration. This is attributed to high hydraulic conductivity of the bentonite-zeolite mixture.     

内蒙古多伦县沸石岩特征研究

本文首次报道内蒙古多伦县的白石头沟口和二等泉两个矿区的沸石岩特征。研究区沸石岩的矿物组合为斜发沸石、蒙脱石、长石、鳞石英、石英和少量的丝光沸石。沸石岩化学成分比较稳定,两个矿区沸石岩的ＳｉＯ２／Ａｌ２Ｏ３比值均在５．６左右,属高硅型沸石岩;白石头沟口沸石岩ｗ（Ｋ２Ｏ）＞ｗ（ＣａＯ）＞ｗ（Ｎａ２Ｏ）;二等泉沸石岩ｗ（ＣａＯ）＞ｗ（Ｋ２Ｏ）＞ｗ（Ｎａ２Ｏ）,属钙－钾型或钾－钙型沸石岩。沸石岩平均吸铵量约为９４×１０－２ｍｍｏｌ／ｇ,阳离子选择交换性能表现为Ｋ＋＞Ｎａ＋,Ｃａ２＋＞Ｍｇ２＋。多数沸石岩的热稳定性可稳定至７００℃不破坏结构。酸碱度平均值为７．３４～７．７５。     

非金属矿物在抗菌材料制备中的应用

介绍了几种非金属矿物(沸石、海泡石等)的结构特点,并简要阐述了以沸石、海泡石和累托石等为载体的金属离子型无机抗菌剂的制备方法及其对各种菌类的抑制情况;天然非金属矿物结构独特,价格低,资源广,作为抗菌剂载体具有很高的应用价值。     

萤石夜明珠有关问题探讨

近年来，中国的各种传媒上不断出现有关夜明珠的报道。引起了广泛的注意，当前市场上出现的夜明珠主要是荧石夜明珠，笔者对荧石夜明珠作了一些初步研究和探讨。发光的原因主要是含稀土元素（rare earth elements)所致，含量可以低至万分数。本文的资料希望能促进对夜明珠问题的深入认识。     

Natural attenuation of TCE, As, Hg linked to the heterogeneous oxidation of Fe(II): an AFM study

Hydrous ferric oxide (HFO) colloids formed, in strictly anoxic conditions upon oxidation of Fe²⁺ ions adsorbed on mineral surface, were investigated under in situ conditions by contact mode atomic force microscopy (AFM). Freshly cleaved and acid-etched large single crystals of near endmember phlogopite were pre-equilibrated with dissolved Fe(II) and then reacted with Hg(II), As(V) and trichlorethene (TCE)-bearing solutions at 25 °C and 1 atm. HFO structures are found to be of nanometer scale. The As(V)–Fe(II) and Hg(II)–Fe(II) reaction products are round (25 nm) microcrystallites located predominantly on the layer edges and are indicative of an accelerated Fe(II) oxidation rate upon formation of Fe(II) inner sphere surface complexes with the phyllosilicate edge surface sites. On the other hand, TCE–Fe(II)–phlogopite reaction products are needle-shaped (45 nm long) particles located on the basal plane along the Periodic Bond Chains (PCBs) directions. Experiments with additions of sodium chloride confirm the importance of the Fe(II) adsorption step in the control of the overall heterogeneous Fe(II)–TCE electron transfer reaction.

Kinetic measurements at the nanomolar level of Hg° formed upon reduction of Hg(II) by Fe(II) in presence of phlogopite particles provide further convincing evidence for reduction of Hg(II)_aq coupled to the oxidation of Fe(II) adsorbed at the phlogopite–fluid interface, and indicate that sorption of Fe(II) to mineral surfaces enhances the reduction rate of Hg(II) species. The Hg(II) reduction reaction follows a first-order kinetic law. Under our experimental conditions, which were representative of many natural systems, 80% of the mercury is transferred to the atmosphere as Hg° in less than 2 h.

The reduction of a heavy metal (Hg), a toxic oxyanion (arsenate ion) and a chlorinated solvent (TCE) thus appear to be driven by the high reactivity of adsorbed Fe(II). This is of environmental relevance since these three priority pollutants are that way reductively transformed to a volatile, an immobilizable and a biodegradable species, respectively. Such kinetic data and reaction pathways are important in the evaluation of natural evaluation scenarios, in the optimization of Fe(II)/mineral mixtures as reductants in technical systems, and in general, in predicting the fate and transport of pollutants in natural systems.     

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in sediments from Hong Kong

Concentrations of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in 14 sediment samples collected from four sites in the Mai Po Marshes Nature Reserve (within a RAMSAR Site) and from another six sites in Victoria Harbour and along the Hong Kong coastline. Elevated levels of PCDDs, and particularly OCDD, were detectable in all samples collected from the Mai Po Marshes and five of the six sites. In contrast to PCDDs, PCDFs were mainly found in sediment samples collected from industrial areas (Kwun Tong and To Kwa Wan) in Victoria Harbour. PCDD/F levels and congener profiles in the samples from the Mai Po Marshes Nature Reserve in particular show strong similarities to those reported in studies which have attributed similar elevated PCDD concentrations to nonanthropogenic PCDD sources.