The determination of sulfide in seawater by flow-analysis with voltammetric detection     

Radwan Al-Farawati  Constant M. G. van den Berg   《Marine Chemistry》1997,57(3-4)

Preliminary measurements of sulfide in seawater using cathodic stripping voltammetry and a hanging mercury drop electrode (HMDE) in batch-mode showed that the sulfide peak decreased rapidly with time. This decrease was not caused by O₂, H₂O₂ or IO₃⁻, and the sulfide peak was not stabilised by trace metal additions. A home-made flow-cell was constructed to enable the determination of sulfide in seawater using voltammetry with an HMDE. A stable sulfide peak was obtained by flow-analysis with voltammetric detection, with a precision of 2.8% and detection limit of 0.5 nM at a 60 s adsorption time. Several thiol compounds were found to produce a peak at, or very close to, the peak potential for sulfide. Their interference was evaluated by allowing the sulfide peak in conventional (batch) voltammetry to decay. Comparative experiments showed that waste metallic mercury is responsible for removal of sulfide in batch-mode analysis due to formation of insoluble mercuric sulfide salts causing the rapid decay of the sulfide peak. The problem is circumvented by using flow-analysis to determine sulfide.  相似文献   

单环刺螠对硫化物暴露的呼吸代谢适应     

张志峰  王思锋  霍继革  邵明瑜  康庆浩 《中国海洋大学学报(自然科学版)》2006,36(4):639-644

研究硫化物暴露后单环刺组织细胞色素氧化酶(CCO)、琥珀酸脱氢酶(SDH)、延胡索酸还原酶(FRD)等呼吸代谢酶活性的变化,初步探讨了单环刺对硫化物的呼吸代谢适应。将虫体暴露于50,150μmol/L 2个硫化物组和不含硫化物的对照组水体中,分别于暴露后0,2,12,24,48 h和解除暴露后48 h取体壁、呼吸肠等组织进行酶活性分析。结果显示:暴露2 h时,硫化物组CCO活性上升。24 h时,150μmol/L组CCO活性显著低于对照组,到48 h时接近于0,而SDH活性显著低于对照组,FRD活性极显著高于对照组。解除暴露后48 h,虫体的呼吸代谢酶活性与对照组无显著差异。可见,硫化物暴露后,短期内虫体呼吸代谢提高,可能进行硫化物氧化解毒。而随着暴露时间的延长,虫体的呼吸代谢减弱,FRD活性极显著增高,推测体内可能存在将延胡索酸还原成琥珀酸的无氧代谢方式。解除硫化物暴露后,虫体具有较强的自我恢复能力。  相似文献   

New Mouth less Interstitial Worms from the Sulfide System: Symbiosis with Prokaryotes   总被引：1，自引：0，他引：1  

J. OTT  G. RIEGER  R. RIEGER  F. ENDERES 《Marine Ecology》1982,3(4):313-333

  相似文献   

胶州湾东部和青岛前海表层沉积物重金属分布特征及其对比研究   总被引：5，自引：0，他引：5  

王红晋  叶思源  杜远生  李绍全  朱爱美 《海洋湖沼通报》2007,(4):80-86

根据2003年对胶州湾东部和青岛前海2008年奥运赛场海域表层沉积物中重金属、有机碳和硫化物的调查结果表明:研究区的重金属(As除外)高含量主要分布在团岛污水处理厂,大港出口北侧至李村河口沿岸一带。作者通过与胶州湾周围岩体、地层和松散沉积物中重金属的平均含量比较以及重金属与环境因子有机碳、硫化物的相关分析,证明了研究区的重金属污染主要来自于工业和生活污水的排放,并且重金属与硫化物的物源不尽相同。作者发现由于胶州湾的潮流作用模式使胶州湾东部排入的污染物向西扩散的可能性削弱,是胶州湾东部污染严重的一个自然因素。同时由于胶州湾东部的部分污染物经由沧口水道搬运到青岛前海的退潮三角洲区域而出现局部高值区,其中沉积物中的Cr和Cu已有超标现象,应引起重视。  相似文献   

Morphotectonics, Volcanism and Hydrothermal Activity on the East Pacific Rise between 21°12′ S and 22°40′ S     

Sergey Krasnov  Irina Poroshina  Georgiy Cherkashev  Evgeniy Mikhalsky  Mikhail Maslov 《Marine Geophysical Researches》1997,19(4):287-317

The morphotectonic setting of the East Pacific Rise (EPR) between21°12 and 22°40 S and its recent and past hydrothermalactivity were the focus of the Russian R/V Geolog Fersmans expeditionin 1987–1988.The EPR axial zone in the study area is comprised of three segmentsseparated by overlapping spreading centers (OSCs) near 21°44 and22°08 S. The northern segment is the shallowest of three and hasa distinct massive axial ridge, trapeziodal in cross-section, toppedby a very wide flat summit surface and cut by a well-developedcentral graben. These features testify to intense magmatism and to avoluminous crustal magmatic chamber underlying the whole segment.Fine-scale segmentation is most clearly revealed in the structure ofthe central graben within which several 4th-order segments can bedistinguished. This scale of segmentation is also reflected on flanks of theaxis by variations in the character and intensity of faulting.According to structural and petrologic data, the magmatism is mostintense in the central part of the segment which is probably locateddirectly over a magmatic diapir supplying the melt to the whole segment.Magma migration at the subcrustal level from the center towards the ends ofthe segment with discrete injection into the crustal magmatic chamber ispresumed.The central segment is broken into two morphologically distinct partsseparated by a deval. In the subsided northern part, the wide summit of theaxial ridge is cut by a well-developed, intensely fractured axialgraben. In the southern part, the axial ridge is relatively elevated, butnarrow with an ephemeral graben along its crest. The character and intensityof faulting on the axial flanks are also considerably different in thenorthern and southern parts of the segment. Thus, the magmatic supply tothese two parts is thought to originate from two different sources. If so,then at present the magma chamber underlying the southern part of thesegment is probably at the stage of replenishment, while in the north it isat the stage of deep cooling.The southern segment is structurally similar to the central one. Howeverthere is considerably less intensive magmatic activity in this region,especially south of 22°30 S where the axial ridge is narrow, andtriangular in cross-section.Both OSCs studied are marked by abrupt narrowing and sharp subsidence ofthe tips of axial ridges within the northern limbs. The southern OSC limbsare morphologically similar to normal sections of axial ridges. In bothcases the flanks are structurally and morphologically disrupted adjacent tothe OSCs and oblique structures can be traced far southward of the OSCflanks. Due to the spatial position of oblique structures on the the flanksit is presumed that the OSC near 22°07 S is migrating northward.The 21°44 S OSC zone has apparently undergone small spatialoscillations. In spite of the small amplitude of lateral displacement, thiszone is marked by prominent bathymetric anomalies.Numerous massive sulfide deposits were discovered atop the axial ridgealong the entire length of the uplifted and hydrothermally active northernsegment. Ore metal concentrations in near-bottom waters are maximumover the southern part of the northern segment, while maximum concentrationsof the same metals in surficial sediments are confined to the central partof the same segment. We surmise that there has been a recentalong-axis shift of the zone of maximum hydrothermal activity fromthe middle of the segment to its present position in the southern part ofthe segment. Considering sedimentation rates, the age of this shift can beapproximately estimated to be 5 to 10 thousand years before the present.The relatively Mg-enriched basalts of the middle part of thenorthern segment represent a tike of a more primitive pattern, while therelatively Fe-rich rocks of its southern part probably reflect alarge degree of fractionation at shallow crustal levels. Considering thistrend, in addition to morphotectonic data we presume that subaxial magmaflow from the middle to the southern part of the segment is responsible forthe along-axis shift of hydrothermal activity.In the central segment of the study area, massive sulfides have only beendiscovered south of the 21°55 S deval, where the axial ridgeshoals and where the existence of a subjacent magma chamber is presumed.The very weak manifestations of recent volcanism within the southernsegment explain the absence of hydrothermal activity and sulfide depositswithin this segment.  相似文献   

中国岩浆型Ni-Cu-(PGE)硫化物矿床的时空分布及其地球动力学背景   总被引：2，自引：0，他引：2  

吕林素　 刘珺张作衡  谢桂青 《岩石学报》2007,23(10):2561-2594

中国岩浆型Ni-Cu-(PGE)硫化物矿床主要出露于中亚造山带(新疆北部的天山-阿尔泰地区)、华北克拉通北缘(吉林-辽宁-北京-河北-内蒙古)和华北克拉通西南缘(甘肃)、扬子克拉通西-北缘(陕西-四川-云南)的广大地区,受控于镁铁质-超镁铁质岩体,具有成群成带分布的特征.这类矿床依其岩石类型和地质特征可划分为3类,即产于镁铁质-超镁铁质侵入体中的基底Ni-Cu-(PGE)硫化物矿床、产于与溢流玄武岩有关侵入体中的Ni-Cu-(PGE)硫化物矿床和产于科马提岩中的Ni-Cu-(PGE)硫化物矿床.这类矿床的成矿时代主要集中于新元古代早期(1 000～800 Ma)和古生代晚期(295～250 Ma)两个时间段,所对应的地球动力学背景分别为Rodinia超大陆聚合与裂解阶段、活动造山带后碰撞和二叠纪溢流玄武岩大规模喷发阶段,且均与超级地幔柱活动有关.这类矿床依其成矿构造环境可划分为4类,即古大陆边缘裂谷型、地幔柱型、弧后拉张型以及造山带后碰撞型.这类矿床按其成矿构造环境、成岩成矿时代和地质特征可划分为4个成矿区带,即新元古代与Rodina超大陆聚散有关的Ni-Cu-(PGE)硫化物矿床、华北克拉通北缘Ni-Cu-(PGE)硫化物矿床、中亚造山带后碰撞Ni-Cu-(PGE)硫化物矿床和峨眉地幔柱区Ni-Cu-(PGE)硫化物矿床.  相似文献   

四川力马河镁铁-超镁铁质岩体的地球化学特征及成岩成矿分析   总被引：4，自引：3，他引：4  

陶琰　胡瑞忠漆亮  罗泰义 《岩石学报》2007,23(11):2785-2800

四川会理力马河镍矿是峨眉山大火成岩省最重要的岩浆硫化物矿床之一,成矿岩体为一小型锾铁-超镁铁岩侵入体,由含斜长石的超镁铁岩(包括舍长辉石橄榄岩和斜长橄榄辉石岩)和辉长岩类的镬铁质岩组成.矿床富含硫化物,成矿元素组合为铜、镍,铂族元素含量很低,没有铂族元素的工业富集,是蛾眉山大火成岩省中富铜镍贫铂族元素的代表性岩浆硫化物矿床.本文对力马河镍矿成矿岩体的镁铁、超镁铁岩及矿床中各种硫化物矿石进行了主量元素、微量元素及铂族元素含量分析.分析结果表明,力马河岩体的镁铁、超镁铁岩属拉斑玄武岩成因系列,岩石特征微量元素比值大致与高钛的峨眉山玄武岩相当、与低钛的峨眉山玄武岩有明显区分,但估计原始岩浆强不相容微量元素绝对含量大大低于高钛玄武岩,因此,其成矿岩体不是与一般的低钛或高钛峨眉山玄武岩(不包括苦橄岩在内)直接对应的深成相.岩体超镁铁岩及矿石铂族元素组成特征表现为无钌亏损的型式,钯/铱比值较小、在5左右,也显著不同于一般的峨眉山玄武岩,而类似于峨眉山大火成岩省苦橄岩的铂族元素组成.运用岩石地球化学研究方法计算,原始岩浆为苦橄质成分:MgO含量约17%、SiO2含量约48%.估计原始岩浆形成于130公里左右的深度,由类似于洋岛玄武岩岩浆源区成分的地幔经19%左右的部分熔融形成.超镁铁岩及硫化物矿石铂族元素含量一般在10-9～10-8暑级,铂族元素相对铜镍强烈亏损,铜/钯比值高于原始地幔10～100倍,铜镍铂族元素组成的原始地幔标准化曲线呈铂族元素显著亏损的“U“型.模式分析说明,导致铂族元素亏损的原因是岩浆成矿演化过程中多阶段硫化物熔离作用造成的,早期熔离出来的硫化物被丢失并造成岩浆中铂族元素亏损,其铂族元素亏损后的岩浆(第)二次硫化物熔离富集形成铂族元素亏损的矿石.  相似文献   

Influence of metal oxides in the colorimetric determination of acid volatile sulfide in sediments     

Janaina L. Oliveira  Alessandra Eugênio  Júlio C. Rodrigues de Azevedo  Jorge Nozaki 《洁净——土壤、空气、水》2006,34(4):383-388

The sediment of Lagoa dos Patos‐MS, Brazil, was investigated to verify the influence of metal sulfides and oxyhydroxides of Mn and Fe on the heavy metal availability. The spectrophotometric method of methylene blue was used, with 8 interlinked tubes containing the samples with SnCl₂, where N₂ was introduced to release the H₂S extracted with 6.0 mol L^–1 HCl, and trapped in 0.05 M NaOH solution. The influence of SO₄^2–, Mn(IV) and Fe(III) oxyhydroxides was investigated with samples constituted by a mixture of MnO₂; Na₂SO₄; FeCl₃, and sediments. The presence of SnCl₂ was very important to avoid the interferences of iron and manganese oxyhydroxides. The method of standard addition was applied and the efficiency was (100.8 ± 9.4)%. The ratio among the quantities of metals potentially available and the acid volatile sulfide (AVS) indicate that the system presents small metals availability to the benthic community, by the existence of sulfide capable to immobilize the metal as insoluble sulfide.  相似文献   

DMS and SO2 Measurements in the Tropical Marine Boundary Layer     

Warren J. De Bruyn  Elizabeth Dahl  Eric S. Saltzman 《Journal of Atmospheric Chemistry》2006,53(2):145-154

Dimethyl sulfide (DMS) and sulfur dioxide (SO₂) mixing ratios were measured in the boundary layer on Oahu, Hawaii in April and May 2000. Average DMS and SO₂ levels were 22 ± 7 (n = 488) pmol/mol and 23 ± 7 (n = 471) pmol/mol respectively. Anti-correlated DMS and SO₂ diurnal cycles, consistent with DMS + OH oxidation were observed on most days. Photochemical box model simulations suggest that the yield of SO₂ and total SO₂ sink are ∼85% and ∼2 × 10⁴ molec cm^{− 3} s^{− 1} respectively. On several days the rate of decrease in DMS and increase in SO₂ levels in the early morning were larger that predicted by the model. Dynamical and chemical causes for the anomalous early morning data are explored.  相似文献   

西昆仑上其汗地区块状硫化物矿床的区域成矿条件   总被引：1，自引：0，他引：1  

匡文龙  刘继顺  朱自强 《矿物岩石地球化学通报》2003,22(1):42-46

块状硫化物矿床是西昆仑地区重要的铜矿床类型之一。为了探明西昆仑地区该类型矿床的区域成矿条件和有关成矿作用过程，本根据翔实的野外资料和系统的采样分析，通过对上其汗典型块状硫化物矿床有关岩矿标本和样品的光、薄片研究与硅酸盐全分析，综合前人资料分析指出，上其汗地区是苏巴什—上其汗加里东期岛弧带的组成部分，大量火山岩的形成为块状硫化物矿床提供了金属元素矿源；深成钙碱性侵入岩为硫化物矿床的形成提供了热源。因此，该区具有中一大型块状硫化物型层状铜多金属矿的找矿前景。  相似文献