Measurement of the total nitrogen in lake sediments： Comparison and its environmental significance

Nitrogen cycle is an important bio-geochemical process in the environment. Measurement of the total nitrogen （TN） is a routine experiment in agriculture, biology and environmental sciences. The Kjeldahl method （KM） and elemental analyzer method （EA） are both commonly used to determine TN. Total nitrogen by EA is the sum of nitrate （NO3）, nitrite （NO2）, organic nitrogen and ammonia. Total nitrogen by KM （TKN） is made up of both organic nitrogen and ammonia. A comparative study focused on the two methods is conducted by analysis of TN in 97 samples from the sediment sequence of Gouchi, a salt lake in North China. KM presents a higher degree of accuracy than EA with a standard deviation of 0.007 vs. 0.024. With the presence of nitrate and/or nitrite nitrogen, however, measurement by KM is considerably lower than that by EA. Therefore, for samples from lake sediment sequences or soils in North China, KM is inapplicable to determining TN because of usually high contents of nitrous salt. Despite the inconsistency, use of both methods to the same samples makes sense in reconstructions of climatic and environmental changes from lake sediments. In Lake Gouchi, the contents of nitrate and nitrite nitrogen vary from 1.40% in the lower part of the sequence to 14.77% in the uppermost part, suggesting a gradual evolution process from a fresh water lake to the present-day salt lake.     

Determination of potential hazardous elements in Can coals （Canakkale- Turkey）-I

It is known that the increasing use of coal as an energy source led to the growing environmental and health problems. But comprehensive knowledge of coal quality parameters may help to reduce some of these problems. The Canakkale-Can coalfield is located in the western part of Turkey, whose reserves are estimated at 69.3 billion tons, mainly used in the industry in the neighboring areas, specifically for the Can Thermal Power Plant. The aim of this study is to determine the coal quality parameters and examine the origin and distributions of potentially toxic trace elements in lignite which may produce environmental and health hazards in the area. The coal samples were collected from different parts of the coalfield in Can. Proximate and ultimate analyses, sulfur form analyses, X-ray powder diffraction （XRD）, inductively coupled plasma-mass spectrometry （ICP-MS）, and scanning electron microscopy （SEM） were performed on those samples to determine the geochemical profile of hazardous elements.     

Elements pollution in the extremely high tumor risk residents in Chaoshan littoral, southern China

Background ＆ aim： To investigate and analyze the elements pollution in the extremely high tumor risks residents in the Chaoshan littoral, southern China. Methods： 19 elements including Cr, Mn, Ni, Sr, Pb, Zn, Co, Sn, Th, Tl, Se, Hg, Cu, Mo, Cd, Sb, U, Ge, As, and Al were measured from 145 hair samples of residents from the high-risk Nanao Island （mortality of cancer 173-156/106 in recent 30 years）, Shantou high-risk village （mortality of cancer 230.4/106 in recent three years）, and two controls Shanwei （mortality of cancer 32/106 in 1970s） and Meizhou Hakka （incidence of cancer 103/106 ） using AAS, AFS, ICP-MS methods collaborated with Beijing University. And 21 samples of water, 18 samples office from the Nanao Island, Shantou high-risk village, and other low-risk controls were measured using the same methods. Results： The element analysis showed that levels of CD, PB in the Shantou high-risk village were the highest, Hg, MN, SR, SB, TH, U on the Nanao Island were the highest in hairs. Conclusions： It is indicated that there occurred elements pollution among the local high-risk population.     

长白山锦北雨养泥炭剖面元素富集规律分析

为了揭示长白山锦北泥炭沼泽区泥炭沉积环境和重金属元素的历史变化及其对环境的指示意义,利用荷兰W ardenaar泥炭采样器采取泥炭样品并对样品进行高分辨率切割。用原子吸收分光光度计和等离子体发射光谱仪测定不同深度剖面Ca,Mg,Na,K,A l,Ti,Cu,Zn,Fe,Mn,Pb,Cr,N i和Co的浓度。研究分析了Ca,Mg,Na,K,A l,Ti,Mn,Zn,Cu,Pb,Cr,N i和Co在泥炭剖面的分布趋势并对其进行了相关分析和富集分析,得出Mn,Zn,Cu,Pb,Cr,N i和Co呈显著相关且在泥炭表层明显累积,揭示出泥炭表层重金属元素的大气沉降来源,表明近年来人类重金属消耗量及排放量的增加是大气沉降重金属元素的主要释放源,而且环境中重金属污染有加重的趋势。     

长白山圆池泥炭氮元素分布特征及其影响因素分析

通过对长白山圆池4个泥炭剖面样品的分析,揭示了其氮元素分布规律。在圆池选取4个具有代表性的采样点,利用泥炭采样器采取新鲜泥炭样品。分析结果表明,4个泥炭剖面氮元素含量在0.014%~3.353%之间;剖面间相比较,其中贫营养泥炭整体含氮量较低;4个泥炭剖面的氮元素分布呈现明显规律,受泥炭上层不同植物、泥炭水分和有机质含量等因素的影响,泥炭剖面中氮元素累积峰可能出现在剖面的表层(0~5cm)或中间层(10~20cm);泥炭剖面氮元素与有机质呈极显著的正相关;泥炭剖面C/N比值变化在9.51~66.98之间,部分剖面层位C/N比值异常高,表明该层位碳的累积速度显著高于氮元素。     

金、银等成矿元素的构造地球化学行为

扬子与华夏地块间发育一条近东西向展布的巨型板块缝合带—华南中部复合混杂岩带,由北东向、近东西向、北北东向三组方位的次级韧性剪切带分支、复合成“网格状”构造阵列。对其次级北东向剪切带(进贤—婺源韧性剪切带)进行的构造地球化学剖面研究发现从剪切带边部至中心,随着剪切程度的逐渐增强,金、铜元素含量逐渐增高,锌元素含量逐渐降低,铅、银元素含量变化不明显、略有降低的趋势;金元素有两个峰值点,一个出现在韧性剪切最强的糜棱岩中,另一个出现在叠加于早期韧性剪切糜棱岩化岩石之上的晚期脆性破裂张性构造角砾岩中,说明韧性剪切及叠加在韧性剪切之上的脆性破裂均有利于金的富集成矿,从而为赣东北地区寻找金矿指明了方向,并为金的成矿构造地球化学理论研究积累了新的素材。     

REE/trace element characteristics of sandstone-type uranium deposits in the Ordos Basin

1 Introduction The Ordos Basin is the second largest sedimentary basin in China. During the last 10 years, a great progress has been achieved in the aspects of tectonic evolution, dynamics process, inner and outer geological processes during Mesozoic-Cen…     

浙江古代青瓷(1127～1279年)的化学组成及其意义

本文用ENGLE-型微探针能量色散X荧光光谱(EDXRF)技术测定了一批青釉瓷残片中的16种元素氧化物的含量,其残片来自浙江杭州地区的南宋郊坛窑和老虎洞窑。由主量元素判别方程的Q值表明,两类青釉瓷均属官窑制品。主成分统计分析看出,郊坛官窑与老虎洞官窑的瓷釉成分有明显不同,但其胎质成分的分布,却有部分的重叠,这显示了当时两处官窑的工匠们在使用胎料中的交往。从釉层、过渡层、和胎层的Al2O3和CaO的含量数据表明,郊坛官窑和老虎洞官窑的青釉瓷制品,分别存有厚度为120～140μm和230～240μm的过渡层,表明两处使用釉料和烧制工艺上的…     

基于PGNAA技术在线分析系统的应用

近年来,随着核探测与分析技术的日趋成熟,使复杂γ谱的获取、解析达到了在线测量的要求,从而使在线PGNAA(中子活化瞬发γ射线分析)技术获得了飞速的发展。它可对一些工业生产过程中的全物料进行在线测量,其分析精度、可靠性等皆能满足在线元素含量分析的需要,因而显示出巨大的发展潜力和广阔的市场前景。这里介绍了基于PGNAA技术的在线分析系统的基本原理、组成和发展,并概述了它在水泥、煤炭等行业的应用情况。     

活性炭富集原子吸收分光光度法测定金

对于低含量的金，碘量法测定终点不敏锐，有返终点现象．用原子吸收分光光度法测定，试样用下水溶解，经活性炭富集，干扰元素基本分离，测定效果良好，提高了分析的准确度及分析速度，可用于0．1g／t以上金的测定．