密云水库和白洋淀鲤鱼耳石矿物与环境响应研究.doc

密云水库和白洋淀鲤鱼耳石矿物与环境响应研究 本研究采用X射线粉晶衍射分析、热释光实验、电子探针分析、中子活化分析、激光剥蚀电感耦合等离子质谱分析等现代矿物学研究手段,初步研究了污染程度较轻的密云水库与污染程度较重的白洋淀的野生鲤鱼耳石矿物与环境的响应关系。组成两地水域鲤鱼耳石的矿物种为球霰石,存在三种晶体结构一种斜方晶系晶体结构和两种六方晶系晶体结构,而以六方晶系晶体结构为主。虽然两地鲤鱼耳石矿物种和晶体结构未见差异;但是属于六方晶系样品在晶胞参数上却存在明显的差异密云水库鲤鱼耳石样品霰石晶胞参数a_0值和晶胞体积总体大于白洋淀的相应值,而c0则小于后者,且前者晶胞参数a_0和晶胞体积比后者更接近于标准样品晶胞相应值。白洋淀鲤鱼星耳石样品的热释光特征值均大于密云水库鲤鱼耳石的相应值。在相同的测定温度下,密云水库鲤鱼耳石缺陷的逃逸几率α均小于白洋淀样品,密云水库鲤鱼耳石缺陷的陷阱深度E均大于白洋淀鲤鱼耳石。两地鲤鱼星耳石耳石微化学特征主要差别在于Sr含量的不同,其次为Zn、As和Ba。Sr与Zn为高正相关性,且不受耳石重量的影响,表明Sr和Zn为相同占位方式,而As和Ba则可能为另一种占位方式。白洋淀鲤鱼耳石相对于密云水库,其元素As、Sr、Ba为阶段性异常,Na存在阶段性波动,Zn则为持续异常,而Au则基本保持不变,两地K基本相似。这些元素的异常情况与白洋淀部分边缘水体受周边企业间歇性排污及生活垃圾有关。通过对鲤鱼微耳石环带进行LA-ICPMS测试分析发现,白洋淀在2002年-2004年9月期间整体看来,在年轮处各元素含量变化较大;绝大部分元素在年轮附近存在阶段性高值。密云水库在1997年-2004年9月期间整体变化情况分两个阶段,在2003-2004年期间,元素变化幅度相对小;而在2002年冬2003年初开始至1997年微量元素变化幅度较大,大部分元素在秋夏期间出现阶段性高值。不同耳石类型其微量元素对环境的响应不同。星耳石中元素Sr、K、Na、Ba、Zn、Cr、Fe、As、Au和微耳石中元素Sr、Na、Ni、Cu、Zn、Pb、Cr、Co受水体中相应元素浓度影响,可作为水环境监测目标元素。两地完全不同水质水域中鲤鱼耳石矿物很好地响应了水化学环境特征。它们在耳石矿物结构、晶胞参数、热释光曲线特征、微量元素含量均体现了两地水域微化学元素的不同,同时也体现了不同时期耳石环带微量元素的不同,这些矿物学特征可作为耳石响应环境可靠的环境指示因子,表明了耳石矿物可作为水环境监测的一种材料。;ReplaceFontEnDivSummary,In this paper, environment responses between carps’otolith minerals and their living environments, Baiyangdian lake, seriously polluted, and Miyun reservoir little polluted, were studied based on X-ray diffraction analysis XRDA, thermoluminescence experiments, electron probe micro-analysis EPMA, neutron activation analysis NAA and laser ablation inductively coupled plasma-mass spectrometry analysis LA-ICPMSA.All samples from two sites are composed of vaterites, which divided into three different crystal structures two types of hexagonal cells and one type of orthorhombic cell; while most samples with hexagonal cells. Though no obvious difference for otolith mineral types and their crystalline structures among the two sites at large, for the vaterites, with hexagonal cell, clear differences exist in these samples from two sites. The dimensions of samples’crystalline cells of vaterites in the otoliths from Miyun reservoir are more nearer to the standards than those from Baiyangdian lake; the a_0 and the cell volumes of the er is relatively bigger than the latter, but c0 are reverse. The a_0 and the cell volumes of the er are nearer to the standards than the latter.The thermoluminescence curve parameters of the fish otoliths from Baiyangdian Lake are greater than those from Miyun reservoir accordingly. At the same testing temperature, the escape probility α of the er is bigger than the latter, and energy gap E inversely.The results show that the main differences between the two sites are the contents of Sr, Zn, As and Ba, ordered by absolute size of correlation within Linar Discriminant Function. High positive correlation exists between Sr and Zn without influenced by otolith weight, which demonstrated that Sr and Zn maybe have the same manner to occupy ion sites in the crystalline structure; while As and Ba maybe have other manner to do it. If the Miyun Reservoir was regarded as no polluted and standard aquatic environment, the contents of As, Sr and Ba elements within otoliths from the Baiyangdian Lake show abnormal intermittently, Na waved intermittently, Zn abnormal continuously, Au unvaried at large, and K nearly same as the Miyun Reservoir. These abnormal contents of elements may be in relationship with intermissive drain contamination from local manufactories and domestic garbage.Trace elemental compositions for rings within otoliths were determined using LA-ICPMS. At large, from Sept. 2004 to the year of 2002, for the curve of elements concentrations within otoliths from the Baiyangdian Lake, elements concentrations vary relatively larger in the rings near the annuli than other rings; most elements concentrations are with moment high values near annuli. In the period from Sept. of 2004 to the year of 1997, the situation for the variations of elements concentrations within otoliths from the Miyun Reservoir mainly divided into two stages. From 2004 to 2003, elements contents varied relatively slightly; from the time, begin in the winter of 2002 and end in the beginning of 2003, to the year of 1997, elements contents varied relatively large; lots of elements concentrations appear high at the period of spring and summer season of a year.For the trace elements contents within otoliths, dynamic responses to aquatic environment hydrochemistry are different due to different otolith types. The contents of elements Sr, K, Na, Ba, Zn, Cr, Fe, As, Au in the asteriscus otoliths and the contents of elements Sr, Na, Ni, Cu, Zn, Pb, Cr, Co within the lapillus otoliths are under the influence of their concentrations in the water; these elements can be used as the target elements to monitor environmetal hydrochemistry.Carps’otolith minerals from these two sites are well responsed to the characteristics of their aquatic hydrochemistry. Distinct discriminations for trace elements concentration between two aquatic environments are shown by otoliths’mineral crystalline structures and their cell parameters, characteristics of thermoluminescence curves, and contents of trace elements. Elements’concentrations in different period in the water are revealed by contents of these elements within otoliths as well. These mineralogical characteristics can be used as reliable hydrochemical proxies; and otolith mineral is a kind of material to monitor aquatic environments.;