利用氮同位素技术识别石家庄市地下水硝酸盐污染源   总被引：36，自引：2，他引：36  

张翠云  张胜  李政红  刘少玉 《地球科学进展》2004,19(2):183-191

地下水NO－ 3污染是石家庄市地下水管理面临的一个主要问题。本次研究通过地下水及其潜在补给源的氮同位素和水化学调查，确定和识别石家庄市地下水NO－ 3污染程度和污染源。地下水中的无机氮化合物主要以NO－ 3形式存在，浓度变化在 2．65～152．1 m g／L之间，均值为（54．88± 31）m g／L（ n＝44），48％的样品浓度超过国际饮水标准（50 m g／L）。地下水样品的NO－ 3－ 15 N值域＋4．53‰～＋25．36‰，均值＋9．94‰±4．40‰（ n＝34）。34个样品中，22个样品（65％）的氮同位素值大于＋8‰；与1991年相比，氮同位素组成指示地下水NO－ 3的主要来源已由当时矿化的土壤有机氮变为现在的动物粪便或污水；结合Cl－分析，南部地下水NO－3还受到东明渠污水的影响。其余12个样品（35％）的氮同位素值变化在＋4‰～＋8‰之间，其中 15 N值较大的（＋6‰～＋8‰）指示来自土壤有机氮，较小的（＋4‰～＋6‰）指示来自氨挥发较弱、快速入渗的化肥厂污水。根据上述研究结果，提出了改善石家庄市地下水管理的措施。  相似文献   

北京北郊冬季低空大气气溶胶分析   总被引：29，自引：4，他引：29  

杨东贞  于海青  丁国安  王淑凤  何耑士 《应用气象学报》2002,13(Z1):113-126

文章分析了2001年1月10～16日和2月20日～3月2日两时段北京北郊中国科学院大气物理研究所325 m高的气象塔上距地面320、100和8 m 3个高度所采得的气溶胶样品的物理化学特征.计算了气溶胶的TSP浓度、化学组分及其分布和粒度谱.探讨了气象条件对气溶胶浓度及其来源和分布的影响.初步发现在所测的高度范围内,气溶胶TSP的浓度随高度的增高而下降,70%以上浓度分布在细粒组(d<2.1 μm).气溶胶中浓度最高的前20个元素是S、Fe、Ca、Al、K、Na、Mg、Zn、P、Ti、Pb、Ba、Mn、Cu、V、As、Cr、 Rb、Sb和Br.挥发性元素主要分布在细粒组,元素浓度随高度增加而减少.气溶胶的离子浓度也有相同的分布特征.风速变小、层结呈现稳定,尤其逆温以及大气湿度升高均为气溶胶浓度升高的因素.人为排放源是大气气溶胶的主要贡献者.导致北京严重空气污染的气溶胶源地以北京当地及其周边邻近地区的污染源为主.  相似文献   

贵州普定纳雍枝铅锌矿矿床成因:S和原位Pb同位素证据   总被引：12，自引：5，他引：7  

金中国  周家喜  黄智龙  罗开  高建国  彭松  王兵  陈兴龙 《岩石学报》2016,32(11):3441-3455

通过近五年(2011~2015)勘查实现找矿重大突破的贵州普定纳雍枝铅锌矿床,位于扬子陆块西南缘,五指山背斜南东翼北中部,是黔西北铅锌成矿区的重要组成部分。矿区内已发现20余个铅锌矿体,探获铅锌金属资源储量超135万吨,是川滇黔接壤铅锌矿集区贵州境内目前已发现和探明规模最大的铅锌矿床。主矿体多呈层状、似层状、透镜状和陡倾斜脉状产出,除了陡倾斜脉状矿体产于F7断层破碎带,其余(似)层状矿体均产于下寒武统清虚洞组和上震旦统灯影组白云岩中,与围岩产状一致,层控特征明显。其矿石类型主要有块状、角砾状、细脉状和浸染状等,矿石矿物以闪锌矿为主,其次为方铅矿和黄铁矿,脉石矿物以方解石、白云石为主,含少量石英,偶见重晶石。本次研究表明,该矿床硫化物δ~(34)S_(CDT)值介于15.94‰~25.49‰之间,均值为22.41‰(n=21),其中黄铁矿δ~(34)S_(CDT)值为22.06‰,闪锌矿δ~(34)S_(CDT)值为19.37‰~25.49‰,均值为23.17‰(n=17),方铅矿δ~(34)S_(CDT)值为15.94‰~19.70‰(n=3),均值为18.23‰。各类硫化物δ~(34)S值部分重叠,总体上不具有δ~(34)S黄铁矿δ~(34)S闪锌矿δ~(34)S方铅矿的特征,暗示硫同位素在硫化物矿物间的分馏未达到平衡。此外,矿石存有少量硫酸盐矿物(重晶石),暗示成矿流体的δ~(34)S3∑S值应高于硫化物的平均δ4S值(22.41‰),接近赋矿地层中海相硫酸盐岩的δ~(34)S值(22‰~28‰)。因此,成矿流体中的还原硫最可能为海相硫酸盐岩热化学还原的产物,来源于赋矿地层中的蒸发岩。应用飞秒激光剥蚀多接收器等离子体质谱法首次获得了纳雍枝铅锌矿中方铅矿原位Pb同位素数据,结果显示Pb同位素组成非常集中(~(206)Pb/204Pb=17.828~17.860,均值17.841,~(207)Pb/204Pb=15.648~15.666,均值15.659,~(208)Pb/204Pb=37.922~37.979,均值37.960,n=32),位于上地壳平均Pb演化曲线上,表明其成矿物质具壳源特征,可能来源于基底岩石。综合矿床地质、矿物学、S和原位Pb同位素数据,本文认为纳雍枝铅锌矿床S主要来源于其赋矿地层,Pb等金属元素主要来源于基底岩石,这两组流体的混合是导致其金属硫化物沉淀成矿的重要机制,成矿流体具后生、低温热液等特征,属于密西西比河谷型(MVT)矿床,很可能形成于燕山期,与右江盆地演化有关。  相似文献   

扬子板块西北缘热水沉积硅质岩稀土元素配分模式的影响因素     

张岩  漆富成  陈文  叶会寿 《地质学报》2018,92(2):378-394

本文对四川省若尔盖县北部-甘肃省迭部县中-下志留统(兰多维列统(Llandovery)-温洛克统(Wenlock))富有机质热水沉积硅质岩及下伏震旦系火山岩进行了以稀土元素地球化学为主的研究,目的是探讨热水沉积硅质岩稀土元素来源及其配分模式的主要控制因素,并建立相应模式图。主要对1个钻孔、2个剖面共28件硅质岩的岩相学、扫描电镜、稀土元素(重点)特征,1个剖面的14件火山岩的主量元素、稀土元素(重点)特征进行了研究。黑色热水沉积硅质岩的岩相学、扫描电镜分析显示,其具有典型的沉积构造特征,后期弱变质;下伏震旦系火山岩样品的TAS图显示其主要为酸性火山岩,少量为基性火山岩。结合前人研究成果,对下伏震旦系火山岩与上覆地层中早-中志留世热水沉积硅质岩的稀土元素对比分析后发现:(1)张性构造环境是产生热水沉积硅质岩的动力学因素,而热水沉积硅质岩稀土元素主要来源于热水流体、古海水(混有陆源物质)、下伏地层中的稀土元素。(2)热水沉积硅质岩的稀土元素的相对丰度中存在一个阈值(或区间):在这个阈值之下,轻稀土元素(LREEs)配分模式及含量与热水流体一致,而重稀土元素(HREEs)配分模式与下伏火山岩的重稀土元素配分模式一致;在这个阈值之上,轻稀土元素(LREEs)配分模式则主要显示了与热水流体混合的古海水(混入有陆源物质)的特征,此时的热水沉积硅质岩的轻稀土元素配分模式及含量与平均上地壳的轻稀土元素配分模式一致,而重稀土元素(HREEs)配分模式仍然与下伏火山岩的重稀土元素配分模式一致。因此,在一定条件下热水沉积硅质岩可以指示古沉积构造环境。  相似文献   

Food web structure of the coastal area adjacent to the Tagus estuary revealed by stable isotope analysis   总被引：1，自引：0，他引：1  

C. Vinagre  C. MáguasH.N. Cabral  M.J. Costa 《Journal of Sea Research》2012,67(1):21-26

The identification of energy sources, pathways and trophic linkages among organisms is crucial for the understanding of food web dynamics. Stable isotopes were used to identify the trophic level of food web components and track the incorporation of organic matter of different origins in the coastal ecosystem adjacent to the Tagus estuary. It was shown that the river Tagus is a major source of organic carbon to this system. Also, the wide difference in δ¹³C among the primary consumers allowed the identification of the pelagic and the benthic energy pathways. The maximum trophic level observed was 2.4 for Sepia officinalis. This value is indicative of a short food web. It was concluded that the diet of the upper trophic level species relies directly on the lower food web levels to a considerable extent, instead of relying mostly on intermediate trophic level species. Moreover, the δ¹⁵N values of primary consumers were very close to that of particulate organic matter, probably due to poorly known processes occurring at the basis of the food web. This lowers the trophic length of the whole food web. Reliance on benthic affinity prey was high for all upper trophic level secondary consumers.  相似文献   

Occurrence and distribution of phthalate esters in riverine sediments from the Pearl River Delta region,South China   总被引：5，自引：0，他引：5  

Hong Liu  Kunyan Cui  Feng Zeng  Lixuan Chen  Yating Cheng  Huiru Li  Shuocong Li  Xi Zhou  Fang Zhu  Gangfeng Ouyang  Tiangang Luan  Zunxiang Zeng 《Marine pollution bulletin》2014

Sixty-eight sediment samples collected from Dongjiang River, Xijiang River, Beijiang River and Zhujiang River in the Pearl River Delta (PRD) region, Southern China, were analyzed for 16 phthalate esters (PAEs). PAEs were detected in all riverine sediments analyzed, which indicate that PAEs are ubiquitous environmental contaminants. The Σ₁₆PAEs concentrations in riverine sediments in the PRD region ranged from 0.567 to 47.3 μg g⁻¹ dry weight (dw), with the mean and median concentrations of 5.34 μg g⁻¹ dw and 2.15 μg g⁻¹ dw, respectively. Elevated PAEs concentrations in riverine sediments in the PRD region were found in the highly urbanized and industrialized areas. Of the 16 PAEs, diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP) and di(2-ethylhexyl) phthalate (DEHP) dominated the PAEs, with the mean and median concentrations of 1.12 μg g⁻¹ dw, 0.420 μg g⁻¹ dw and 3.72 μg g⁻¹ dw, and 0.429 μg g⁻¹ dw, 0.152 μg g⁻¹ dw and 1.55 μg g⁻¹ dw, respectively, and accounted for 94.2–99.7% of the Σ₁₆PAEs concentrations. Influenced by local sources and the properties of PAEs, a gradient trend of concentrations and a fractionation of composition from more to less industrialized and urbanized areas were discovered. As compared to the results from other studies, the riverine sediments in the PRD region were severely contaminated with PAEs. Information about PAEs contamination status and its effect on the aquatic organisms in the PRD region may deserve further attention.  相似文献   

开滦苯加氢精制工程环境风险评价          下载免费PDF全文

王绪鑫  徐新阳  张宇晨 《气象与环境学报》2008,24(1):67-71

以某苯加氢精制工程为例,探讨了焦化行业环境风险评价方法;利用该项目所在地近3 a地面常规气象观测资料,分析了当地的污染气象特征;采用风险识别、源项分析、后果计算、风险评价等环境风险评价技术方法,筛选出主要风险因子并进行风险预测,采用多烟团模式并考虑气象因素进行风险计算。结果表明:污染事故发生后,苯类物质的地面浓度最大值为3 214 mg/m3,位于距离事故发生源WNW方向约50 m处超标1 339倍,由此可知近距离污染严重;高浓度污染物主要集中在污染源附近,随着距离的延长,污染物浓度不断向下风向扩散,超标范围在6 km内。利用简化分析法,定量给出此项工程的最大可信事故风险值为7.6×10-6/a,小于化工行业风险值8.33×10-5/a,此工程风险值水平与同行业比较在可接受的范围内。  相似文献   

Formation of Dibenzodioxins and Dibenzofurans in the Photochemical Transformation of Polychlorinated Phenols     

Yu. I. Skurlatov  L. S. Ernestova  E. V. Vichutinskaya  D. P. Samsonov  R. I. Pervunina  I. V. Semenova  V. O. Sjvydly 《洁净——土壤、空气、水》1998,26(1):31-35

It is shown that in the direct photolysis of polychlorinated phenols (2,4,5-TCP, PCP) in aqueous solution, under the action of solar light or UV-radiation from artificial sources, polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF) are found among the products of transformation. A mechanism is suggested of formation of these toxic compounds via the intermediate formation of free radicals. In the oxidation of chlorophenols by singlet oxygen, free radicals are not formed. Addition of fulvic acids prevents formation of PCDD and PCDF in solar light, possibly as a result of trapping of intermediate radicals.  相似文献   

太湖富营养化污染源及其生态控制方法     

张永春  孙勤芳  李维新  武志林 《湖泊科学》1998,10(S1):101-110

In accordance with the natural, geographic, and ecological characteristics of the Taihu Lake Basin, and the relation between the water body of Taihu Lake and its surrounding environment, an area, which has tight relevance with the water environment of Taihu Lake, was token as the main investigation region. The area was named as the Taihu Lake Region. Some factors, such as TN, TP, COD_Cr that characterized the main environmental problem, the eutrophication were selected when conducted the pollution sources investigation on in Taihu Lake Region. The categories, distribution, pollution contribution to the Lake of dijferent pollution sources, as well as the routes of pollutants entering the Lake were basically made clear. Pollution sources that must be preferentially controlled and the direction of controlling those main pollutants, such as TN, TP, CODCr, were proposed. Base on the investigation, a series of eco-systematic approaches for controlling Taihu Lake eutrophication were put forward. They are ecosystem regulation, nutrient substances transferring along food chain, trophic masse degrading step by step along the route from a pollution source to the Lake, building ecological preventive zone of the Lake, as well as the ecological measures for point sources treatment and so on.  相似文献   

西藏舍索矽卡岩型铜多金属矿床年代学与地球化学特征及意义   总被引：6，自引：1，他引：5  

赵元艺  崔玉斌  吕立娜  石登华 《岩石学报》2011,27(7):2132-2142

舍索矿床位于西藏申扎县北部,属班公湖-怒江成矿带中段,为小型矽卡岩型铜多金属矿床。本文在野外地质调查和室内岩矿鉴定基础上开展了锆石LA-ICP-MS U-Pb法测年、主量与微量元素测试、H-O、C、S和Pb同位素、流体包裹体拉曼光谱、包裹体温度与盐度分析。矿区成矿岩体花岗闪长岩年龄为116Ma, A/CNK值在1.0附近,A/NK值在1.62~1.88之间,为准铝质与过铝质的过渡类型。微量元素蛛网图中,富集大离子不相容元素Rb、Th、Pb、Ti,贫Nb。稀土配分模式属于右倾型,重稀土部分的曲线形态平缓,∑REE=89.89×10^-6~97.92×10^-6,∑LREE/∑HREE=7.47~9.31,δEu=0.75~0.89,具有不明显的负Eu异常。矿床形成于班公湖-怒江洋向南(即冈底斯地块)俯冲碰撞闭合之前的岛弧环境。石英包裹体流体主要为岩浆水。方解石的δ¹³C_V-PDB(‰)=-3.6~ -2.0;δ³⁴S_V-CDT(‰)=-10.3~2.7,以负值为主,出现-8.5‰与-3.5‰两个峰值,辉钼矿的δ³⁴S 出现较大的负值。花岗闪长岩的锶钕同位素显示其源区为幔源,在上升过程中受到下地壳物质的影响。包裹体均为气液两相包裹体,气相成分主要为CO₂,有少量的N₂与CH₄。气液比(%)为5~45,大小为3×6~33×20μm。测试的均一温度范围为130~290℃,主要介于180~260℃,盐度主要介于3%~6% NaCleqv和10%~18% NaCleqv,总体显示为低温低盐度特点。成矿物质由岩浆与地层共同提供。  相似文献