鲤鱼耳石Micro-CT特征与水域中重金属元素响应关系研究

将激光剥蚀等离子质谱技术(LA-ICP-MS)及显微X射线断层扫描技术(Micro-CT)运用到鲤鱼耳石对水环境中重金属元素的响应关系研究中. LA-ICP-MS结果表明白洋淀水域鲤鱼耳石中的Cu和Pb含量大于密云水库相应元素的含量;Micro-CT数据统计表明白洋淀水域鲤鱼耳石的Micro-CT值高于密云水库鲤鱼耳石的Micro-CT值.原子序数大的重金属元素Cu和Pb的富集程度是导致两研究区水域Micro-CT值差异的主要原因.耳石中的元素与水体元素具有相似的分布趋势,且对水体中的相应元素有明显富集作用.因此,鲤鱼耳石Micro-CT特征与水环境中重金属元素存在一定的耦合关系,可作为标型特征指示水体中重金属元素信息.     

不同水域鲤鱼耳石微化学特征及其环境指示意义

利用中子活化分析对密云水库与白洋淀水域两个不同水域（无污染水域和重污染水域）中鲤鱼耳石的微量元素进行分析，发现白洋淀鲤鱼耳石中Sr、Zn、As、Au、Ba、K、Na的含量明显比密云水库鲤鱼耳石的相应元素含量高。采用线性判别方法对两地耳石中Sr、Zn、As、Ba4种元素进行分析，表明存在明显的分组差异，而且两地的差别主要在于Sr含量不同，其次是Zn、As和Ba；白洋淀鲤鱼耳石中As、Ba、Sr、Na等元素含量变化幅度比密云水库鲤鱼耳石中相应元素含量的变化幅度大，与白洋淀水域废水排放时间上的周期性和短暂性导致元素在耳石部分日轮上沉淀等因素相吻合。两地鲤鱼耳石微量元素特征存在截然的区别，与两地水域水体中微量元素差异相一致，表明鲤鱼耳石微化学特征具有水化学环境指示意义，为进一步研究利用鲤鱼耳石进行水化学环境监测或恢复鲤鱼生长期水环境特征奠定了基础。     

鱼耳石微化学特征在湖库水质评价中的标型意义——以河北白洋淀和北京密云水库野生鲤鱼为例

对河北白洋淀和北京密云水库的野生鲤鱼耳石和水体中的微量元素进行了定量分析。白洋淀鱼耳石中诸微量元素含量均高于密云水库的鱼耳石,反映了白洋淀各水体较密云水库水体的环境复杂,污染程度高。统计分析结果表明,在鱼耳石中大致存在两类生物地球化学习性不同的元素,水体中第一类元素的变化不会引起耳石中相应元素的响应,如Au、K和Na;第二类元素的变化会引起耳石中相应元素的强烈响应,如As、Ba、Co、Cr、Fe、Sr和Zn。诸微量元素在耳石中富集的强弱顺序为,Zn>Sr>Se>Fe>As>Ba>K>Co>Au>Na>Cr。通过相关性分析发现,白洋淀和密云水库的鱼耳石和水体中对应微量元素平均含量的自然对数值之间均存在良好的线性关系。     

白洋淀和密云水库野生鲤鱼耳石热释光特征研究

鱼耳石的主体由生命矿物文石组成，其研究在过去二三十年中已取得了不少成果，但是将热释光技术用于鱼耳石的研究未见报道。本文对生长在河北白洋淀和北京密云水库的野生鲤鱼耳石的热释光曲线特征进行了研究，分析了两水域野生鲤鱼耳石中陷阱深度（E）值的差别。热释光测试结果显示，白洋淀10颗鲤鱼耳石样品热释光曲线的峰点温度（T）、发光强度（J）、积分强度（S）和半高宽（w）的均值大于密云水库，而且前者热释光曲线各参数值和E值的稳定程度均不如后者。分析还表明白洋淀鱼耳石在不同温度下的电子和空穴的逃逸几率（α）均大于密云水库。据调查，白洋淀各水体较密云水库水体的环境复杂，污染程度高。研究结果表明，鱼耳石的热释光曲线特征对鱼所生长的水体水质和水环境相当敏感，通过更深入研究，可能成为水质和水环境的重要标型。     

不同水域鲤鱼耳石CaCO3晶体结构特征与环境响应初探

鱼耳石主要成分是CaCO3,主要以文石(或霰石)形式存在,在过去四、五十年来在晶体结构研究方面取得了较多的成果.然而,不同水域鲤鱼耳石CaCO3晶体结构信息特征与环境响应研究却未见报道.本文对密云水库和白洋淀水域鲤鱼耳石X-粉晶衍射结果进行了研究,并分析了两地晶胞参数a0、b0、c0和单位晶胞体积的差异.结果显示,两地耳石样品均由霰石组成,分属三种不同结构:两种六方晶系P63/mmc(no.194)结构和一种斜方晶系Pbnm(Pnma no.62)结构.属于六方晶系的耳石样品中,密云水库鲤鱼耳石样品晶胞参     

野生鲤鱼耳石中蛋白质的提取与表征

通过对北京密云水库的野生鲤鱼的微耳石和星耳石中的蛋白质进行提取,分别得到了3种基质蛋白,根据其在提取过程中溶解性的不同,分为水可溶蛋白(WSP)、酸可溶蛋白(ASP)和酸不可溶蛋白(AIP).通过高效液相色谱、X射线衍射、红外光谱分析和氨基酸成分分析等方法分别对3种基质蛋白进行了表征,发现微耳石和星耳石中3种基质蛋白特征存在差异,并初步推断蛋白质特征的差别与碳酸钙晶体在微耳石和星耳石中的不同晶型有关.     

鱼耳石中锶和钡富集的影响因素及其环境响应

鱼耳石中元素锶和钡主要来源于鱼类生存的水体,这两种元素通过腮或肠进入内耳淋巴液,继而以类质同象的方式沉淀在耳石晶格内部空位和晶格间隙中。耳石结晶沉淀的整个过程不仅受生物的调控作用,而且还受到外界环境,如水体元素浓度、盐度、温度等因素的影响,因此耳石中某种元素的浓度与其在水体中的浓度之比(元素富集系数)与鱼类所生存的环境之间具有一定的响应关系。在以上各种因素中,水体元素浓度对耳石元素富集系数的影响最为显著。一般来说,耳石中某种元素的含量与水体中相应的元素浓度呈正相关关系,而水体中元素之间就耳石中的富集过程也存在一定的相互促进或抑制作用,如Sr对Ba为协同作用,Ca对Sr、Zn为拮抗作用。另外,水体盐度或温度与元素富集系数之间不存在简单的线性相关关系,而是因鱼种、水体综合环境及元素种类不同而有所差异。研究结果表明:鱼种一定的情况下,耳石中元素富集系数与水体盐度和温度存在良好相关关系。基于以上相关性分析,可以认为耳石中元素富集系数与环境因子(水体元素浓度、盐度、温度)之间存在响应关系。因此,可以选用那些受环境影响大但对自身调控影响小的元素(如:Sr、Zn、Pb、Mn、Ba、Fe、Li、Ni、Cd)来建立耳石与水体环境之间元素富集系数的定量化模型,并利用这种响应关系及定量化模型进行生态环境监测和渔业管理。     

不同水域鲤鱼耳石CaCO3晶体结构特征与环境响应初探

鲤鱼耳石共有三对:矢耳石、微耳石、星耳石;分别存在于球状囊、椭圆囊、平状囊(听壶)中,具有重要的感应平衡、运动、重力和声音的作用.     

鄱阳湖水系重金属元素地球化学特征及入湖通量

江西省多目标区域地球化学调查显示,鄱阳湖流域河流两岸土壤(河漫滩沉积物)中存在明显的重金属异常带。为揭示河流两岸河漫滩沉积物(土壤)中重金属元素的来源、输送通量及其沉积历史,分别于丰水期和枯水期系统采集了鄱阳湖流域赣江、信江、饶河、抚河、修水及鄱阳湖湖水、悬浮物等样品,分析As、Cd、Pb等元素含量。研究表明：As、Pb、Cu、Zn等元素在研究区河流中的含量普遍较高,不同时期河水中的元素含量有较大的差异;各重金属元素在研究区河流迁移形式有很大的差别,As和Cd主要以离子态形式迁移,但Cd悬浮态迁移形式所占比例也很大;Pb、Zn、Cu和Ni主要以悬浮态形式迁移;重金属在河流水体和悬浮物两相中的分配受水体pH值、温度和悬浮物浓度等因素影响,不同的元素受这些因素的影响程度有很大的差别;按各支流输送通量,赣江和信江对湖区重金属元素输入通量的贡献最大,是鄱阳湖Cd等重金属元素的最主要来源。     

淮南塌陷塘重金属空间分布特征研究

长期地下煤炭开采在地表产生了大面积的塌陷塘,并造成了不同程度的水域污染。为研究塌陷塘重金属的分布特征及成因,选择了8种对环境影响较大的重金属元素（Fe,Mn,Zn,Cu,Cr,Cd,Pb,Ni）为研究对象,以淮南潘集一矿塌陷塘为研究区域,利用ArcGIS地统计模块中的协同克里格算法,通过水体实测光谱反射率作为协变量来估算水体中的重金属含量空间分布特征。结果表明:水体实测光谱与重金属含量有较好的关系,以水体光谱为协变量的协同克里格插值与单变量的普通克里格插值相比,8种重金属元素的预测值与实际值之间的均方根误差明显减少,证明水体实测光谱适合作为协变量来估计水体重金属的空间分布情况。综合分析发现,水体中的Cd,Pb,Cu,Ni主要来自水域西北部的煤矸石堆山,且Cd,Cu,Pb含量均超过了当地的背景值,对环境影响较大;Cr主要来自农业肥料、成土母质和周边道路旁的煤泥灰厂及煤矸石堆;Zn的来源主要是煤矸石、上游生活污水、农业肥料、土壤母质,由于其含量较低,对水环境质量的影响不大。      

鱼耳石的成因矿物学属性:环境标型及其研究新方法

鱼耳石是鱼类头骨两侧的组织器官，是典型生命矿物文石的载体，发育明显的环带结构。其环带数和韵律层厚度反映鱼龄和鱼体生长速率；其δ^8O值能指示水体温度。利用环带的几何学特征、颜色、常量和微量元素特征与氧同位素和碳同位素组成结合，可有效地鉴别鱼的种群结构，追索鱼的源区、迁移习性、营养水平，记录水体环境的变迁，预测未来水体环境变化趋势，指导渔业生产战略布局。本文首次开发的鱼耳石之文石纳米形貌和热发光参数，可有效地指示相应水体的环境特征，用于进行不同来源区的判别和鱼类资源管理。     

A field experiment testing for correspondence between trace elements in otoliths and the environment and for evidence of adaptation to prior habitats

Site-specific variation in the trace element composition of fish otoliths can be used to identify fish to source, but the mechanisms controlling elemental composition are poorly understood. Environmental influences on the deposition of barium (Ba), copper (Cu), manganese (Mn), and strontium (Sr) in the otoliths of mudsuckers (Gillichthys mirabilis) were tested using a reciprocal field transplant experiment, in which fish from 3 estuaries were transplanted to each of the 3 estuaries. Fish originating from the 3 estuaries showed no differences in otolith chemistry that might reflect acclimation to past conditions in their home estuary or genetic differences among populations, which simplifies the interpretation of otolith chemistry. Cu and Mn concentrations in otoliths differed according to the site of transplant. Cu in otoliths showed the same pattern of difference among estuaries as did Cu in sediments, but there was no correspondence between Cu in otoliths and dissolved Cu. Ranked differences among estuaries in otolith Mn matched the ranking of estuary-specific differences in dissolved Mn, and there was no correspondence between the concentration of Mn in otoliths and sediments. Fish transplanted to different estuaries showed no differences in otolith concentrations of Ba or Sr, and the concentrations of Ba and Sr in the water column showed a similar lack of difference among estuaries. This study provides field evidence supporting the conclusion that the elemental composition of otoliths reflects environmental conditions to which fish have been recently exposed, but whether that correlation is with trace elements in the sediment or water column can vary.     

Analysis of geological Sr isotope markers in fish otoliths with subannual resolution using laser ablation-multicollector-ICP-mass spectrometry

In this pilot study, laser ablation-multicollector-inductively coupled plasma-mass spectrometry (LA-MC-ICP-MS) and Sr isotope geochemistry were applied to fish life-history studies through the micro-analysis of Sr abundance and ⁸⁷Sr/⁸⁶Sr in the otoliths of an anadromous fish. With a laser sampling area of 70-µm diameter, LA-MC-ICP-MS of a deep-sea coral gave precision values for ⁸⁷Sr/⁸⁶Sr determination of approximately 0.04% relative standard deviation with an accuracy to <1C of seawater. Analyses of different sides of the same otolith and different otoliths from the same fish gave reproducible results overall, which suggested that at the Sr concentrations found in the freshwater portions of the otoliths (ca. 500 µg/g) LA-MC-ICP-MS can be reliably employed. Subtle isotopic differences occurred between a pair of otoliths from one fish, which may be due either to sampling resolution limitations imposed by the size of the laser spot, or to asymmetrical otolith growth which incorporated environmental Sr in one otolith but not the other at certain times. New information about fish provenance which could not be gained from Sr concentration data alone included insights into the movements of individuals between isotopically contrasting freshwater environments. LA-MC-ICP-MS of calcified tissues, in combination with Sr isotope geochemistry, has the potential to retrieve new data about fish life-history movements which complement the information from other techniques.     

Microfocus X-ray computed tomography analysis of corroded glass objects

Microfocus X-ray computed tomography (µCT) is a useful tool for non-destructive analysis of corroded archaeological glass objects and for monitoring restoration and conservation processes for these materials. This was demonstrated by µCT analysis of artificially corroded laboratory-produced glasses and corroded archaeological glasses retrieved from soil environments. Corrosion layers with a thickness of 20 µm or more can be detected as areas with lower X-ray attenuation values than the non-corroded glass. Features that are revealed by µCT analyses include the degree and patterns of corrosion and the presence of various internal structures in the corrosion layers. The study of restored corroded glasses demonstrates that mechanical and laser cleaning can be monitored efficiently. The study of consolidation practices, using test objects, requires the use of additives to increase X-ray attenuation values of the organic compounds that are used.     

Recent progress in X-ray CT as a geosciences tool

For many years X-ray computed tomography has been widely used as a medical diagnostical tool. This non-destructive technique was soon found to be very useful in rock material research. In the 1970s CT was introduced in material research while in the 1990s, micro-CT became an important non-destructive research technique. Presently nano-CT is being developed creating even more possibilities for the 3D visualization of small objects. In this paper CT, micro-CT and nano-CT are specified and discussed. Several applications illustrate the possibilities, specific advantages and limitations of each instrument. As with every technique some restrictions occur, but X-ray CT is found to be an emerging non-destructive analytical technique with many possibilities in material research.