黄石市罗桥地区土壤镉污染的环境地球化学特征

对黄石市罗桥地区土壤中镉元素污染的环境地球化学调查研究表明：1）罗桥地区土壤Cd的背景值为0.068×10-6. 2）不同性质的土壤中,Cd的全量及有效态含量也有差异.其含量大小依次为：排放污水水沟污泥 > 水稻土 > 岗地土. 3）距污染源不同距离、不同深度的土壤样品中Cd的污染程度也不同.Cd污染主要集中于土壤的表面,很少向下迁移.污水样品中的Cd含量也随着排污上游到下游因污水的净化能力增强而降低. 4）对于各污染土壤样品,土壤中各形态Cd含量关系依次为：残余态 > 交换态 > 铁锰氧化物结合态 > 水溶态 > 有机态.5）因污水排放及污水灌溉引起的水型污染是罗桥地区土壤Cd污染的直接来源.大冶有色金属冶炼厂废气排放也是罗桥地区土壤Cd污染的另一个原因.     

黄原胶改性微米铁修复地下水中Cr(Ⅵ)污染的试验

为了解决微米铁的重力沉降问题,提高微米铁修复地下水Cr（Ⅵ）污染的原位修复效果,本文利用黄原胶对微米铁进行改性,并通过沉降实验探究改性微米铁浆液的稳定性,同时选择Cr（Ⅵ）作为目标污染物,探究黄原胶改性微米铁去除地下水Cr（Ⅵ）污染的降解能力。实验结果显示：当黄原胶的投加质量浓度分别为0.0、1.0、1.5、2.0、2.5、3.0、6.0 g/L时,改性微米铁浆液的悬浮稳定性逐渐得到加强,在5 h沉降实验结束时,对应的相对分光光度值分别为0.05、0.25、0.46、0.57、0.65、0.73和0.87;黄原胶具有抑制微米铁吸附Cr（Ⅵ）的能力,其可促进Cr（Ⅵ）的还原,提高Cr（Ⅵ）的去除率;随着黄原胶投加质量浓度的增加,对应的Cr（Ⅵ）去除率分别为33.4%、41.2%、47.4%、51.1%、53.0%、63.9%和64.1%;6.0 g/L黄原胶改性的微米铁浆液具有最佳的悬浮稳定性,黄原胶的投加提高了微米铁的反应活性,但当黄原胶投加质量浓度超过3.0 g/L时,其对Cr（Ⅵ）的去除率没有显著提高;黄原胶投加质量浓度越大,黄原胶的缓冲作用就越明显。     

湖南株洲地区Cd、Pb污染土壤的修复实验

以海泡石、膨润土和生石灰为修复材料,对湖南株洲地区重金属元素Cd、Pb污染农田土壤进行了室内修复实验。盆栽小白菜的正交实验结果表明,对于Cd含量为1.23 mg/kg、Pb含量为136.7 mg/kg的土壤,当每10 kg土壤添加膨润土60 g、海泡石20 g、石灰6 g时,种植的小白菜中Cd含量为0.154 mg/kg,Pb含量为0.141mg/kg。与未修复土壤的实验结果对比,小白菜中Cd含量降低61%,Pb含量降低46%。     

STUDY ON THE RELATIONSHIP BETWEEN SPECIATION OF HEAVY METALS AND THEIR ECOTOXICITY——I. TOXICITY OF Cu, Cd , Pb AND Zn IN SEAWATER TO THREE MARINE ALGAE IN THE PRESENCE OF DIFFERENT COMPLEXATION AGENTS

Heavy metal is a main pollutant in the marine ecosystem . so study on the effect of heavy metal on phytoplankton is important . Algae (Chaetoceros sp . , Dunaliella sp . ., Dicrateria zhanjiangenis Hu . var . sp .) were laboratory cultured to observe the effect of heavy metals on their growth . The effect of different metal ion concentration , the detoxication effect of complexation agents and the growth of algae in different media and different nutrition levels were studied to evaluate the effect of metal speciation . It is proved that trace amount of heavy metals can stimulate the growth of algae cells but that high concentration is lethal . The sequence of toxicity is Cd2+>Zn2+>Pb2+ . In ordinary nutrition conditions , the detoxication sequence of complexation agents to Chaetoceros sp . is EDTA > sodium salicylate > sodium oxalate > sodium citrate > sulfanilic acid > O-phenanthroline . This is in good conformity with the stability constant sequence of these agents with copper and good evidence that t     

Optimal Filtering Algorithm for Stochastic 2-D FMM Ⅱ with Multiplicative Noise

A stochastic two-dimensional Fornasini-Marchesini's Model Ⅱ (2-D FMM Ⅱ) with multiplicative noise is given,and a filtering algorithm for this model, which is optimal in the sense of linear minimum-variance, is developed. The stochastic 2-D FMM Ⅱ with multiplicative noise can be reduced to a 1-D model, and the proposed optimal filtering algorithm for the stochastic 2-D FMM Ⅱ with multiplicative noise is obtained by using the state estimation theory of 1-D systems. An example is given to illustrate the validity of this algorithm.     

Determination of Chromium, Nickel, Copper and Zinc in Milligram Samples of Geological Materials Using Isotope Dilution High Resolution Inductively Coupled Plasma-Mass Spectrometry

A simple and accurate method for the determination of Cr, Ni, Cu and Zn at μg g^?1 levels in milligram‐sized bulk silicate materials is reported using isotope dilution high‐resolution inductively coupled plasma‐mass spectrometry (HR‐ICP‐MS) with a flow injection system. Silicate samples with Cr, Ni, Cu and Zn spikes were digested with HF‐HBr and Br₂, and subsequently decomposed at 518 K in a Teflon bomb. In this procedure, all sulfides and chromite, major hosts of these elements, were completely decomposed, thus allowing for isotope equilibration between the sample and spike. Magnesium and Al fluorides formed after the digestion of the sample were removed by centrifugation, and the supernatant was directly aspirated into a HR‐ICP‐MS at a mass resolution of 7500, where interfering oxide ions, ArO⁺, CaO⁺, TiO⁺, CrO⁺ and VO⁺, were separated from Cr⁺, Ni⁺, Cu⁺ and Zn⁺. No matrix effects were observed down to a dilution factor of 50. Detection limits for these elements in silicate samples were < 0.04 μg g^?1. The effectiveness of the technique was demonstrated by the analysis of 13 to 40 mg test portions of USGS and GSJ silicate reference materials with a major element composition ranging from andesite to peridotite, in addition to 8‐23 mg of the Smithsonian reference Allende. Both the reproducibility and the deviation from the reference value for most reference materials of various rock types were < 9%, and thus confirm that the method gives accurate analytical results for small sample sizes over a wide range of Cr, Ni, Cu and Zn contents. This method is, therefore, suitable for analysing small and/or precious bulk samples, such as meteorites, mantle peridotites and mineral separates, and for the characterisation of silicate and sulfide minerals for use as calibration samples in secondary ion mass spectrometry or laser ablation ICP‐MS.     

Tannery Effluents: Current Practices,Environmental Consequences,Human Health Risks,and Treatment Options

The tannery industry influences the gross domestic product/economic activity of any country, but the uncontrolled release of tannery effluents causes environmental degradation and increases health risks to human. The reason for the toxicity of tannery effluents is the presence of high concentrations of organic and inorganic chemicals used in the production of leather goods. Untreated or partially treated effluents discharged into surface water results in an increase in both chemical and biological oxygen demand as well as in an increase in the levels of total suspended solids, dissolved solids, and toxic metals in environmental bodies, especially in soil, water bodies, and water sediments. Various treatment techniques, such as physicochemical, biological, and advanced oxidation methods, which include chemical precipitation, electrocoagulation, aerobic or anaerobic treatment, wetland construction, and Fenton, electro-Fenton, and photo-Fenton processes are also described. This review also discusses the technical appropriateness and economic feasibility of reducing the effluent pollution load and solid waste emanating from the tannery industry. Considering the enhanced health risks in the tannery waste treatment and management regime, some green and advanced technologies should be explored. A sustainable green technology that avoids the use of toxic chemicals in the tanning process is seen well for ecological health.     

成都经济区土壤光谱特征及其意义

对成都经济区内的根系土壤样品进行了光谱测试分析。针对不同土壤类型和不同成土母质，总结了光谱特征，并对土壤分类做了初步的研究。结果表明：①violet（紫光）、blue（蓝光）光谱与根系土壤CA含量都成正相关；②yellcw（黄光）、orange（橙光）、redness（红光）波段光谱与根系土壤CA含量呈负相关；③可以通过紫光、橙光的组合初步判断出土壤类型。     

白垩纪大洋缺氧事件2(OAE 2)期间的百年到千年周期

太阳周期是地球气候系统的重要调节因素之一。深时地质时期由于时间跨度长以及高分辨率数据的缺乏, 导致太阳周期的研究还存在欠缺。本研究以北美西部内陆海白垩纪Iona-1钻孔岩芯Eagle Ford组(42~153.41 m)为对象, 以泥灰岩中明暗纹层的高分辨率(230 μm)灰度数据为载体, 开展了详细的旋回地层学分析。结果表明, 白垩纪大洋缺氧事件2(OAE 2)期间存在781~1150 a、188~242 a、79~126 a、38~50 a的周期信号。通过与过去9400年以来重建的太阳总辐照度(TSI)对比, 这些周期被解释为太阳周期中的Eddy周期(约1000 a)、de Vries-Suess周期(200~250 a)、Gleissberg周期(88~120 a), 其中38~50 a的周期虽然在全新世太阳活动记录中未发现, 但地质时期存在类似的周期, 认为可能是Bruckner周期(30~50 a)。Bruckner周期仅在OAE 2期间存在, 这可能是由于不同的沉积环境导致不同时间段对该周期的差异性响应。结合深时中已发现的一些太阳周期记录, 本研究认为太阳活动在过去几十亿年中有效地影响了气候变化, 从而影响沉积过程。太阳活动对陆地气候和大气-海洋过程产生影响, 进而导致了海洋有机物含量、氧化还原条件和生物群落的差异。这些因素共同促成了北美西部内陆海白垩纪沉积物中毫米级明暗纹层的形成。上述研究成果可为深入了解OAE 2气候效应以及现今温室效应下的极端气候变化提供一定借鉴。