Chemical contamination of a coral reef by the grounding of a cruise ship in Bermuda   总被引：1，自引：0，他引：1  

Jones RJ 《Marine pollution bulletin》2007,54(7):905-911

Bulk metal analyses of surficial sediments collected around the Norwegian Crown cruise ship grounding site in Bermuda indicated significant but localized contamination of reef sediments by copper and zinc, caused by the stripping of the tri-butyltin (TBT)-free antifouling (AF) paint (Intersmooth 460) from the underside of the hull. Highest copper and zinc values were found in heavily compacted and red-pigmented sediments inside the impact scar and were comparable to levels found close to slip ways of local boat yards where AF paints from hull stripping and cleaning processes are washed into the sea. The re-distribution of AF contaminated sediments by storms and deposition on nearby reefs constitutes a significant ecological risk that could delay recovery processes and reduce the effectiveness of remediation efforts. Whilst the ecotoxicological effects of AF paint particles interspersed with sediment is unknown, and in need of further study, it is argued that the significance of AF paint contamination of grounding sites has been overlooked.  相似文献   

LiBr溶液从低浓度到高浓度的分子动力学模拟          下载免费PDF全文

李军 Brick.  J 《盐湖研究》2000,8(4):8-18

在 L i Br与水的物质量比分别为 1∶ 64、1∶ 32、1∶ 16、1∶ 8、1∶ 4和 1∶ 3的情况下 ,对 L i Br溶液从低温到高温的分子动力学模拟进行了研究。随浓度增加 ,锂离子的水合数量呈减少趋势但同时又从 L i+- Br-接触离子对的数量增加中得到补偿 ,而 L i离子的第一配位壳层的配位数量保持不变。在高浓度 Li Br溶液中 ,Br- O之间的距离有所增加 ,Br-- O的径向分布的形状更趋于非对称 ,从而很好地确定了 Br离子水合壳层 L i+- Br-接触离子对可以在更稀的溶液中产生 ,但随浓度增加而增加。L i+- Br-距离明显短于溶液中 Li离子与 Br离子的离子半径之和 ,也短于 L i Br晶体中两者离子半径之和。高浓度溶液中水分子的结构几乎被破坏 ,水分子间的氢键明显增加 ,但没有消失。对 L i+、Br-和水的扩数系数计算值与实验值进行了比较  相似文献   

黄河口磷酸盐缓冲机制的研究Ⅱ.黄河口磷—钙矿物的离子平衡     

石晓勇  史致丽 《海洋与湖沼》1999,30(6):737-743

1994年5月—1995年6月,利用黄河口悬浮颗粒物,在实验室内于不同温度、盐度、磷酸盐浓度、pH值及悬浮物粒度条件下进行了悬浮物对磷酸盐的吸附和解吸模拟实验,通过水体中几种磷—钙矿物的离子平衡计算,对黄河口磷酸盐的缓冲机制进行了探讨。结果表明,黄河口现场条件下水体中钙与磷之间存在某些离子平衡,黄河口水体中磷—钙矿物的离子积受温度、悬浮物种类及粒度影响较小,而与水体盐度、磷酸盐及钙含量有关,但不足以形成磷—钙矿物沉淀;磷—钙矿物的沉淀和溶解在黄河口磷酸盐浓度的控制机制上所起的作用较小,而悬浮颗粒物表面对磷酸盐的吸附和解吸起了较大的作用。  相似文献   

Sheath effects on DEMETER ion drift measurements     

Richard Marchand  Nelson Knutson 《Planetary and Space Science》2010,58(10):1365-1373

The “Instrument d’Analyse du Plasma” on DEMETER includes an ion drift meter used to measure the direction of the incoming ram plasma ( [Berthelier et al., 2006a] and [Berthelier et al., 2006b]). Given the velocity of the satellite, and expected flow velocities of plasma along DEMETER's orbit, it is estimated that at mid latitudes, the direction of incident plasma as measured by IAP should be within approximately 2° of the ram direction. Yet, significantly larger angular deviations are measured routinely. An important assumption made in the interpretation of onboard instruments, such as IAP, is that neither the spacecraft nor the instrument significantly perturb the plasma that is being measured. In view of the large observed angular deviations, this paper examines the possible effect of the electrostatic sheath surrounding IAP. This is done with the 3D PIC simulation code PTetra. The model uses a full 3D particle in cell code with unstructured tetrahedral mesh capable of accurately representing the satellite geometry. The mesh is also adaptive so as to provide a fine spatial resolution in the vicinity of the particle sensor where it is needed, and a coarse resolution in regions where plasma parameters vary over a longer scale length. Calculation results show that while particle deflection associated with the electrostatic sheath near IAP can account for appreciable angular deflections for representative ionospheric plasmas, they are typically smaller than the ones observed. Additionally, the model is unable to reproduce the latitudinal dependence of the observed large deflection angles. It is concluded that sheath effects may cause appreciable distortions on the IAP type of ion flow meter instruments, and on other particle sensors in general. The larger observed deviations and their latitudinal dependence, however, must be attributable to other physical processes not accounted for in the model.  相似文献   

The construction and development of SHRIMP I: An historical outline     

John J. Foster 《Precambrian Research》2010

In 1973 Bill Compston advocated the building of an ion microprobe at the Research School of Earth Sciences (RSES) at the Australian National University (ANU). The commercial ion probes available at this time were too small to have sufficient sensitivity for trace element analysis and too low in mass resolution to avoid molecular interferences. The project commenced in 1974 with the appointment of a former ANU PhD student Steve Clement who had expertise in beam transport theory. To achieve high sensitivity and high mass resolution, beam transport theory indicated that a much larger magnet than in any commercially available mass spectrometer would be required. Clement chose an ion optical design, by Professor Matsuda of Osaka University in 1974, which had the required combination of high mass resolution and high transmission. Clement's job was to produce the detailed scientific designs and machine drawings for the new instrument as well as testing the completed instrument. Clement coined the term SHRIMP-Sensitive High Resolution Ion MicroProbe. By the end of 1977 nearly all the components had been manufactured and the big electromagnet had been successfully tested. In the following year the secondary mass analyzer was assembled and tested using a thermal ionization source and showed great promise with flat-topped peaks at 5000 resolution and 50% transmission with 50 V energy spread. At this stage the machine had far exceeded the specifications for the available commercial ion probes. Continued development during 1981 to the point where the original design specifications were fully realized was time consuming since learning how to use the entirely novel instrument was no simple task; no one else had an instrument like SHRIMP. The application of the instrument to zircon U–Pb geochronology established the necessary operating conditions for measuring Pb isotopic compositions and the elemental ratios Pb/U and U/Zr from 20 μm diameter spots on single zircon grains. Application of this in the early 1980s started a revolution in Precambrian geology by the ability to produce rapidly accurate and precise age determinations on structurally complex zircon samples.  相似文献   

山东金刚石碳同位素组成的二次离子质谱显微分析   总被引：1，自引：0，他引：1  

张健  陈华  陆太进  丘志力  魏然  柯捷 《岩矿测试》2012,31(4):591-596

华北克拉通山东金刚石晶体生长的多阶段性及碳同位素组成已被人们关注,但很少有人对不同阶段金刚石及其内部的碳同位素组成变化进行分析。本文利用二次离子质谱(SIMS)微区分析技术对山东金刚石晶体内部不同阶段生长的δ13C进行了原位测试分析,得出山东金刚石δ13C的变化范围在-5.6‰～-2.01‰,平均值为-3.63‰,与前人对华北克拉通金刚石碳同位素组成测试值(δ13C在-14.71‰～-0.46‰,主要集中在-9‰～-4‰之间)大致相同,位于全球橄榄岩型金刚石及幔源碳同位素组成主要范围(-8‰～-2‰)内。结合金刚石生长环带阴极发光图像,认为金刚石自核心部位至边缘,在同一期生长环带内,其δ13C值呈变重趋势;在多期复杂生长环带之间,δ13C值因结晶时的地质环境不同而存在差异。δ13C值的这种变化揭示了该地区金刚石复杂的生长环境,为解析华北克拉通地幔碳循环提供了定量数据。  相似文献   

扩散-离子色谱法测定植物样中的氟          下载免费PDF全文

曹磊  赵斌  周泳德 《江苏地质》2012,36(2):216-218

采用扩散法提取植物样中的氟,用离子色谱法检测氟的含量。经试验,样品加标回收率在94.7%～104.7%之间,样品质量分数为7.10μg/g时,RSD为1.41%。此法操作简单,准确度高,精密度好,是一种测量植物样中氟含量的有效方法。  相似文献   

Effects of mineral-organic fertilizer on the biomass of green Chinese cabbage and potential carbon sequestration ability in karst areas of Southwest China     

Qibiao Sun  Yulong Ruan  Ping Chen  Shijie Wang  Xiuming Liu  Bin Lian 《Acta Geochimica》2019,(3):430-439

The karst mountain areas of Southwest China contain barren farmland soils and suffer from nutritional and water deficiencies that affect crop productivity. Hence,it is imperative to apply suitable fertilizers to restore soil fertility and maintain crop yield. The aim of this study is to investigate the effects of mineral-organic fertilizer(MOF)made of potassic rock and organic waste on the growth of crops. For this purpose, green Chinese cabbage grown using three different fertilization methods including MOF,inorganic fertilizer(IF), and a control was evaluated. We determined soil water content, agronomic characteristics,and biomass of green Chinese cabbage in different treatments. Furthermore, surface runoff from the pot experiments and soil leachate from pot experiments were collected to determine water temperature, pH, and cation and anion concentrations. The results demonstrate thatMOF can improve the soil water-holding capacity of soil,and the basic agronomic characteristics of the cabbage treated with MOF were superior to those with IF. Using MOF can promote the increase in cabbage biomass.Additionally, the concentration of inorganic carbon(largely in the form of HCO_3^-) in surface runoff water treated by MOF was higher than the other treatments, establishing carbon sequestration potential. This work provides a novel and environmentally friendly fertilization pattern in karst areas, which will improve crop yield and also increase the carbon sequestration potential of crops.  相似文献   

中性厌氧环境中硫酸盐还原菌导致锌的腐蚀行为研究     

全雨  窦雯雯  韩晓梅  蒲亚男  宋翼  陈守刚 《海洋科学》2020,44(11):28-35

以锌为研究对象，使用表面表征方法和电化学测试，研究了一个培养周期内硫酸盐还原菌（Sulfate-reducing bacteria，SRB）Desulfovibrio vulgaris（D.vulgaris）引起锌（Zn）试样腐蚀行为的影响。实验结果表明，SRB导致Zn试样发生了严重的均匀腐蚀和点蚀。浸泡7天后，SRB体系中的Zn试样平均失重为32.2 mg/cm²，是无菌培养基中试样平均失重的42倍，腐蚀产物主要为ZnS。生物膜和腐蚀产物膜的累积在培养初期可以减缓金属基体与溶液界面的电子传输过程，导致腐蚀速率减缓。培养中后期，由于生物膜和腐蚀产物膜的阻隔作用，导致混合膜层底部有机碳源缺乏，SRB转向Zn获取自身所需电子，表现为腐蚀速率上升。  相似文献   

中国雾水化学研究进展   总被引：6，自引：3，他引：3  

李子华  刘端阳  封洋  朱彬  张国正  杨军  濮梅娟 《气象学报》2011,69(3):544-554

1980年以来,中国雾水化学研究发展迅速.在城市、高山和海边广泛地开展了雾的观测试验和云雾水的取样分析,研究了各地云雾水的酸度和酸雾的来源,分析了不同地区雾水化学组分的基本特征.许多雾的综合观测试验,在对雾水连续取样的同时,还连续观测了与雾水化学相关的要素,研究了影响雾水化学组分浓度的主要因子.文中总结了近30年来中国...  相似文献