Mired in the past — looking to the future: Geochemistry of peat and the analysis of past environmental changes

Peat cores from ombrotrophic bogs have been used as a valuable archive to study environmental change for over a century. Much of this focus on the peat record has been on biological proxies of environmental change, such as pollen and peat-forming macrofossils, but there is growing interest in the geochemical record to study environmental changes. Several studies of long-term peat records in Europe have reconstructed past changes in atmospheric lead pollution, for example, and the general cohesiveness of the results and their agreement with known historical trends in metal production exemplify the best potential of peat geochemistry as an environmental archive. Based on the success with lead, a current emphasis in peat reconstructions is to assess the record of past mercury deposition and results thus far show generally consistent trends, e.g., a pre-anthropogenic mercury accumulation rate of about 0.5–1.5 μg Hg m^− 2 year^− 1. Despite this general consistency there is increasing concern that there may be diagenetic effects on the quantitative record of some metals, which can be inferred based on a strong relationship between mercury and other organically bound elements and proxies for peat decomposition (C/N ratio). However, it is possible that changes in decomposition and the alteration of some metal records could provide climatic information. A few recent studies show that closer examination of the geochemical matrix, in some cases along with biological proxies, can provide valuable information on landscape changes and climate; for example, partitioning metals into different weight fractions and source regions can be applied to climate studies. The best interpretations of the peat geochemical record in the context of environmental and climate change will likely come when geochemical and biological records are considered simultaneously.     

铁炉子断裂带侧旁地质体的构造解析及找矿方向研究

本文以构造变形为主线,将沿铁炉子断裂带侧旁的地质体划分为不同的构造均匀区段。解析了不同区段内的变形特征,总结了包括矿体就位方式和后期改造在内的综合地质事件演化序列。指出了铅锌矿的找矿方向及其它金属矿产的找矿线索。     

贵州施秉白云岩溶蚀特性及孔隙特征实验研究

以贵州施秉白云岩为研究对象,从宏观和微观角度分析白云岩的溶蚀特性及孔隙特征,结果显示:(1)在众多影响施秉喀斯特发育的因素中,矿物成分是最基本的内因,水是最关键的外因,孔隙结构起辅助作用。(2)极细晶白云岩的单位表面积溶蚀量一般大于细晶白云岩的,在晶粒相同的情况下,白云岩的溶蚀量与Ca O和Mg O的含量分别成正比,且Mg O的含量影响较Ca O大。(3)施秉白云岩溶蚀速率不仅受岩石矿物颗粒粒径大小的控制,还受岩石内部孔隙结构特征的影响,颗粒粒径越大,孔隙度越高,连通性越好,越有利于水溶液进入,溶蚀量也就越大。(4)施秉白云岩的溶蚀特性是多种因素综合作用的结果,必须把各个因素分离开来,从宏观和微观角度逐个作详细的分析研究,然后综合起来,才能对喀斯特发育规律有更深入的了解。     

荣成海流能电站海上钻探技术研究

根据洛庄汉墓封土堆土壤汞含量异常值特征,推测主墓室的位置有3处,2处分布在洛庄汉墓封土堆南北中心线偏东部位,另一处分布在封土堆南北向中心线的西部。高精度磁测推测封土堆西部呈东西方向展布的M1(D1)异常为古墓通道,往东呈南北向展布的M2(D2),M3(D3),M4,M5异常为主墓室。土壤汞含量测量与高精度磁测2种方法推测的主墓室位置及范围基本吻合。该次调查为下一步洛庄汉墓主墓室的发掘提供了翔实的地质依据。     

Levels and distribution of tris-(2,3-dibromopropyl) isocyanurate and hexabromocyclododecanes in surface sediments from the Yellow River Delta wetland of China

The levels and distribution of tris-(2,3-dibromopropyl) isocyanurate (TBC) and hexabromocyclododecanes (HBCDs) of surface sediments in the Yellow River Delta wetland had been investigated. The concentrations of TBC and ∑ HBCDs ranged from 0.20 to 29.03 ng·g^? 1 dw and below limits of detections (LODs) to 20.25 ng·g^? 1 dw. The average composition profile of three HBCDs isomers were 10.1%, 6.1% and 83.8% for α-, β- and γ-HBCD, respectively. Moreover, correlation analysis indicated there are similar sources among three isomers and positive correlations between total organic carbon (TOC) content and concentrations of TBC and HBCDs. The mass inventory of TBC,α-, β-, γ-HBCD, ΣHBCDs in surface sediments of Yellow River Delta wetland were estimated about 725.50, 72.76, 44.29, 548.34, 665.39 kg. Therefore, further investigations on potential human health and environmental risk assessments of TBC and HBCDs were needed.     

卤虫无节幼体的营养强化对黑斑口虾蛄(Oratosquilla kempi)幼体发育的影响

用扁藻、酵母、“鱼油 酵母”强化和“不强化”4种方式处理的卤虫无节幼体投喂黑斑口虾蛄各期幼体,比较不同强化方法对黑斑口虾蛄幼体成活率、变态率、生长速度及总脂与脂肪酸组成的影响。结果表明,3种方式强化12h后的卤虫无节幼体与对照组相比,总脂含量都有不同程度的增加。卤虫无节幼体的脂肪酸组成与强化方式密切相关,其中“鱼油 酵母”强化的卤虫无节幼体20∶5n-3(EPA)和22∶6n-3(DHA)占总脂肪酸的比例最高,分别为5·74%和4·84%。投喂强化后富含EPA和DHA的卤虫无节幼体,可增加黑斑口虾蛄幼体体内脂肪酸尤其是EPA和DHA等不饱和脂肪酸的含量,从而提高其幼体的成活率、变态率与发育速度。     

贵州百花湖表层水中不同形态汞的分布规律

均匀布点采集百花湖表层水样44个,对水样不同形态汞含量进行了分析,并现场测定水质参数。采用经典统计学与半变异函数拟合相结合的方法,研究了百花湖表层水中不同形态汞含量的空间变异性。根据半变异函数拟合的结果,在ArcGIS软件的支持下进行克立格插值,以此来揭示百花湖表层水中不同形态汞含量的空间分布规律。研究表明:百花湖表层水中的汞污染主要来自上游,随水体流动汞污染减少;但也有一些区域可能因富营养化而使颗粒态汞和总汞含量增加。     

上海黏土压缩回弹变形的微观机理

黏土变形微观机理的研究过去多针对土体加载压缩开展,随着研究的深入,黏土卸载回弹变形的微观机理也逐步得到重视,但目前对此研究还很少。本文采用单向压缩及回弹试验、扫描电镜及压汞试验对上海黏土压缩及回弹变形过程中土体的微观特性及其变化进行了研究。研究结果表明,微观结构参数的变化能反映黏土的宏观变形特征。在加载过程中,随固结压力增加,土体孔隙体积减小,孔隙数量先增加再减小,孔隙平均形状系数的增加先急后缓,孔隙形态分维数先急剧减小后缓慢减小。在卸载过程中,随固结压力减小,孔隙数量增加,平均形状系数略有减小,孔隙形状分维数略有增加。加载压缩过程中,固结压力较小时中、小孔隙体积所占比例变化不大,而当固结压力较大时小孔隙所占比例显著增加、中孔隙所占比例明显减小。在卸载回弹过程中,各级固结压力下小孔隙都占绝对优势,但固结压力较大时中孔隙所占比例较大,而固结压力较小时中孔隙所占比例较小,黏土卸载回弹变形主要是小孔隙体积的少量增加。     

太湖水体的总磷分布及湖流对其影响的数值研究

用数值模拟的方法研究了太湖水体中ＴＰ分布特征及湖流对其影响,推导,建立了包括平流,水平扩散,沉降和底泥释放的浅水湖泊中污染物浓度分布计算的二维迎风有限元数值模式,并在给定若干点源条件下计算各种稳态流场下太湖水体中的ＴＰ分布。     

RG-1测汞仪软件介绍

RG1测汞仪操作软件使用VC++5.0工具研制,在Windows95下运行。通过AD/DA接口实现对RG1的控制和对基准电压的自动跟踪校正。完全的可视化操作。具有4种可选的标准曲线拟合方法以用于不同浓度样品的峰值和积分值测量,并直接给出汞浓度及各种统计数据