Controlling mechanisms for the trace metals, (Cu,Zn, Cd,Fe, Co and Ni) in anoxic sea water in Saanich Inlet,British Columbia,Canada

A study was conducted on Cu, Zn, Cd, Fe, Co and Ni levels in Saanich Inlet anoxic seawater. Data on the concentration of these trace metals and H₂S, and other oceanographic parameters were obtained in four cruises. Equilibrium models are presented together with in situ data. The results strongly support the assumption that the solubilities of Cu, Zn, Cd, Fe, Co and Ni are controlled by bisulfide and/or polysulfide complexes. The species of Cu, Zn, Cd and Ni are shown to be Cu(S₄) ₂ ³⁻ and Cu(Sn₄S₅)³⁻, Zn(HS) ₂ ⁰ and ZnHS ₂ ⁻ , Cd(HS) ₂ ⁰ and Ni(HS) ₂ ⁰ , respectively. The solid species controlling Fe²⁺ and Co²⁺ are respectively the pyrohotites FeS and CoS. The data illustrates that thermodynamic equilibrium has been established in the H₂S-controlled seawater of Saanich Inlet, and that equilibrium has not been established in the H₂S−O₂-coexisted seawater of Saanich Inlet. The lack of equilibrium in the H₂S−O₂-coexisted seawater is a result of the flushing or mixing of oxygenated seawater with anoxic water. The new species of trace metals are still in the processes of reduction and precipitation. Contribution No. 1428 from Institute of Oceanology, Academia Sinica     

Sea flux of trace metals in Saanich Inlet

The sea fluxes of trace metals, POC, and settled material were studied in anoxic seawater, Saanich Inlet, B. C., Canada with sediment traps. This paper discusses the change of mass fluxes of sediment, trace metals and POC for various seasons and depths. The annual mean of settled material is 1.56 g.m⁻².a⁻¹, 84.6 mg. m⁻².a⁻¹ for POC, 60.0 mg. m⁻².a⁻¹ for Cu, 16.5 mg.m⁻².a⁻¹ for Pb, 189 mg.m⁻².a⁻¹ for Zn, 2.20 mg.m⁻².a⁻¹ for Cd, 699 mg.m⁻².a⁻¹ for Fe, 38.8 mg.m⁻².a⁻¹ for Co, and 84.6 mg.m⁻².a⁻¹ for Ni. The relations between the average fluxes of trace metals and POC, the fluxes of trace metals and settled matter, and the sea fluxes of trace metals and Fe are in linear progression. The resident times of elements as calculated from sea flux, are 1.1 a. for Cu, 0.014 a. for Pb, 0.50 a. for Zn, 3.8 a. for Cd, 0.16 a. for Fe, 0.39 a. for Co, and 1.14 a. for Ni. The order of resident times is as follows: Pb−Fe−Co−Zn−Cu−Ni−Cd. The metal resident times in Saanich Inlet are shorter than the values estimated for the open ocean. It illustrates that the biochemical processes in shallow Saanich Inlet are faster than those in the open ocean, and that debries of plankton and fecal pellets of zooplankton play an important role in vertical transport of organic carbons. Contribution No. 1650 from the Institute of Oceanology, Academia Sinica.     

A study on the flux,speciation, and budget of mercury in controlled experimental ecosystems

The lowest addition of mercury (0.1 ug Hg 1⁻¹) was used in CEEs for research on mercury flux, speciation and budget. The removal behavior of mercury by phytoplankton in water columns of CEEs can be described by first order kinetic equations for total and particulate mercury in the CEE spiked by mercury. The removal rate of mercury in water columns depends on the size and productivity of phytoplanton in a water column to which mercuric ions were added. A 4.4 day half-life time and a 2.8 day half-life time for total and particulate mercury respectively was obtained in diatom bloom. During microflagellate bloom a 30 day total mercury half-life time was estimated with increase of particulate mercury in the water column. The 0.010 ug Hg cm⁻²y⁻¹ mercury flux rate that was attained in the control bag agreed with the values from field measurements in Saanich Inlet where the bags were launched. The proportion of total mercury to dissolved and particulate mercury depended also on the size, productivity, and concentration of mercury in a water column. A more or less constant distribution of mercury species in the control bag was observed as follows: dissolved Hg 0.73, particulate Hg 0.27, inorganic Hg 0.42, dissolved organic Hg 0.31. After spiking with mercury, the particulate mercury rose rapidly and reached to over 70% of the total mercury. The concentration factor of mercury by phytoplankton in the CEEs in the order of 10⁵ was consistent with the results from field measurements in Saanich Inlet. The mercury recovery from the water column, sediment, water with sediment, and the CEE bag walls was only 52.3% of total mercury spiked in the CEE. The losses of mercury by vaporization into the ambient air and diffusion through the wall of the enclosure should be considered. This paper was published in Chinese inOcean. Limn. Sinica,17(4):307–317, 1986.     

Study on kinetics of cathodic reduction of dissolved oxygen in 3.5% sodium chloride solution

Electrochemical reduction of dissolved oxygen in seawater on metals is of great importance for corrosion studies. The present paper studied cathodic reduction of dissolved oxygen on Q235 carbon steel in 3. 5% sodium chloride(NaCl)solutions by cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS), rotating disk electrode(RDE)and rotating ring-disk electrode(RRDE). The cyclic voltammetric results demonstrated the cathodic process on Q235 carbon steel in O2-saturated 3. 5% NaCl solution contains three reactions:dissolved oxygen reduction, iron oxides reduction and hydrogen evolution. The peak potential of oxygen reduction reaction(ORR)is-0. 85 V vs Ag/AgCl, 3 molL-1 KCl. The E1S results indicated that the ORR occurring on Q235 carbon steel is a 4-electron process and that no finite diffusion is caused by the intermediate of H2O2 produced by ORR. The RDE and RRDE voltammograms confirmed the EIS results and it was found that the number of transferred electrons for ORR was nearly 4, I. E. , dissolved oxygen reduced to water.     

BIOCHEMICAL STUDIES ON “SUB-MICROMETER PARTICLES" AT DAYA BAY I. STUDY ON CONCENTRATION, DISTRIBUTION AND CORRELATION OF TRACE METALS IN DIFFERENT SIZE FRACTIONS

ＩＮＴＲＯＤＵＣＴＩＯＮＣｏｌｌｏｉｄｓ (ｏｒｓｕｂ ｍｉｃｒｏｍｅｔｅｒｐａｒｔｉｃｌｅｓ)ａｒｅｏｐｅｒａｔｉｏｎａｌｌｙｄｅｆｉｎｅｄａｓｐａｒｔｉｃｌｅｓｂｅｔｗｅｅｎ 1ｎｍａｎｄ1 μｍ (Ｖｏｌｄ ,Ｒ .Ｄ .ａｎｄＶｏｌｄ ,Ｍ .Ｊ.,1 983) .Ｔｈｅｄｉｓｔｒｉｂｕｔｉｏｎｂｅｔｗｅｅｎ“ｄｉｓｓｏｌｖｅｄ”ａｎｄ“ｐａｒｔｉｃｕ ｌａｔｅ”ｐｈａｓｅｉｎａｑｕａｔｉｃｃｈｅｍｉｓｔｒｙｕｓｅｄｔｏｂｅｄｅｆｉｎｅｄｂｙａｆｉｌｔｒａｔｉｏｎｗｉｔｈ 0 .45 μｍｐｏｒｅｓｉｚｅｆｉｌｔｅｒｓ.Ｔｈ…     

Study on Dissolved Trace Metals in Sea Surface Microlayer in Daya Bay

Glass-plate sampling during 1988- 1999 in Daya Bay and suitable corresponding analytical methods were used for the measurement of dissolved trace metals, dissolved organic carbon, biological oxygen demand, chemical oxygen demand, salinity of the sea surface mierolayer and subsurface water. Apparent enrichment mechanism and diurnal variation have been revealed for dissolved trace metals in the microlayer in Daya Bay. The more dissolved organic matter was enriched in the sea surface microlayer, the more dissolved trace metals were enriched in the layer. The organic matter played an important role in the enrichment process. The diurnal variations of dissolved trace metals showed that their concentration was apparently inversely related to the tide activity that the concentration was low during rising tide, but high during falling tide. The behavior of dissolved trace metals expressed by the diurnal variation was clearly opposite to that of salinity.     

Analysis of Cu,Co, V and Zn in coastal waters of the East China Sea by inductively coupled plasma mass spectrometry (ICP-MS)

In this study, a simple method for the simultaneous determination of trace metals(Cu, V, Co, Zn) in coastal seawater using the Mg(OH)2 coprecipitation inductively coupled plasma mass spectrometry(ICP-MS) was developed. This multi-element method enables the simultaneous extraction of four metals, particularly Co and V. The recoveries of Cu, Co, V and Zn after Mg(OH)2 coprecipitation were 73%, 96%, 94% and 92%, which means that our procedure was well-suited to the determination of these four trace metals. The detection limits were 3.81, 0.18, 6.09 and 1.91 nmol L-1, respectively. Then, applying this method to the simultaneous determination of these four metals in coastal water samples from the East China Sea revealed that the concentrations of Cu, Zn, Co and V were higher in bottom waters compared to water at other depths, and higher concentrations were generally observed at the Yangtze River estuary. Additionally, example vertical profiles of dissolved trace metal concentrations for the East China Sea in spring and autumn are compared. These findings indicate that Zn had the greatest seasonal variation followed by Cu, V and Co. For Zn and Co, the concentrations were higher during spring than during autumn. For Cu and V, the seasonal variation in the concentrations was opposite.     

Heavy metals in sediments of Yellow Sea and East China Sea: Chemical speciation,distribution, infl uence factor,and contamination

Metal species and the degree of environmental pollution are related to the hydrogen sulfi de(H 2 S), an important product of early diagenesis that can react with metals to form stable compounds. To investigate the eff ects of H 2 S to metals and evaluate metal environment eff ect in the sediments of the East China Sea(ECS) and Yellow Sea(YS), geochemical characteristic and spatial distribution of nine heavy metals and H 2 S profi le were studied. Higher H 2 S content and lower metal content was observed in the sediments 10 cm in depth in the North Yellow Sea and the west coast of South Korea. The pollution load index( I pl) indicates that the southern coast of Shandong Peninsula underwent moderate pollution( I pl =1) of heavy metals and no heavy metal pollution appeared in other areas( I pl 1). To some extents, the ecological risk of Cd and As enrichment was moderately severe in all stations. The chance of heavy metal combination to be toxic in ECS and YS during summer was 21%. In addition, correlation between H 2 S content and metals in both solid and porewater phases was obvious, corroborating important eff ect of H 2 S on metal distribution. Moreover, H 2 S could aff ect the spatial distributions of heavy metals in porewater directly and be indicative of potential biological eff ects of combined toxicant groups in the study region.     

CALCULATION FOR THE DISSOLVED QUANTITIES OF OIL SPILLED AT SEA

Laboratory and field experiments on the dissolution of oil showed that the quantity of the dissolvedoil component in the seawater depends on its solubility, concentration in the pertroleum, and theenvironmental conditions. The vertical oil concentration in calm sea decreases exponentially with depth.The vertical diffusion coefficients and dissolution constants of the N-pareffin from C_(12) to C_(21), totaliso-paraffin, cycle-paraffin and aromatic components in calm sea were calculated, and the oil dissolution in-to seawater was determined to be about 0.52% in 48 h for No. 0 light diesel oil.     

Dissolved oxygen distribution and O2 fluxes across the sea-air interface in East China Sea waters

This study on the sectional and vertical distribution of dissolved oxygen (DO) and the O₂ fluxes across the sea-air interface in East China Sea (ESC) waters shows that the waters were in steady state and that the difference of DO was great in upper and bottom waters in Apr. 1994; but that seawater mixing was strong and the difference of DO was small in upper and bottom waters in Oct. 1994. The above conclusions were specially obvious in continental shelf waters under 100 m. The DO maximum in subsurface layer waters appeared only at several stations and in general the DO in the waters decreased with depth. The horizontal distributions of O₂ fluxes across the sea-air interface appeared in stripes in Leg 9404 when most regions covered were supersaturated with O₂ seawater to air flux was large, and that on section No. 1 was 1.594 L/m²·d. The horizontal distribution of O₂ fluxes across the sea-air interface appeared lumpy in Leg 9410, when most regions covered were unsaturated with O₂·O₂ was dissolved from air to seawater, and the fluxes were 0.819 L/m²·d on section No. 1 in Leg 9310, 0.219 L/m²·d in Leg 9410. The main reasons for DO change in surface layer seawater were the mixture of upper and bottom layer water, and the exchange of O₂ across the sea-air interface. The variation of DO by biological activity was only 20% of total change of DO. Contribution No. 2716 from Institute of Oceanology, Chinese Academy of Sciences.     

Acid volatile sulfide and simultaneously extracted metals in tidal flat sediments of Jiaozhou Bay,China

It is well known that acid-volatile sulfide （AVS） plays an important role in influencing the toxicity of divalent cationic metals within anoxic sediments. In studying sediment core samples collected from tidal flats within the Jiaozhou Bay, China, we found that the AVS concentration gradually increases with depth and decreases from high tidal flat to low tidal flat areas. We evaluated the chemical activity and bioavailability of heavy metals in the tidal flat based on the molar ratio of simultaneously extracted metals （SEM） and AVS. The value of SEM/AVS is generally less than 1 in this area except for the surface layer, which suggests that the heavy metals only have chemical activity in the surface layer. SEM is most highly concentrated at the boundary of the redox layer SEM have similar depth distributions throughout the tidal flat. The aeration of low tidal flat sediment indicates that SEM gradually move to deeper sites via interstitial water.     

FLUXES OF SEAWATER AND SOME DISSOLVED CHEMICALS IN THE BASHI STRAIT

An Acoustic Doppler Current Profiler (ADCP) was used in Nov. 1990 measure the seawaterfluxes in a southeast-northwest cross-section in the Bashi Strait to a depth of 400 m. Measuredconcentrations of dissolved oxygen (DO), phosphate (PO_4), nitrate (NO_3), silicate (SiO_2), total alkalinity(TA) and calculated total CO_2, (TCO_2) and the current speed were used to estimate the flux densities(concentration times current speed) of seawater and chemicals.The fluxes of nutrients were near zero near surface and increased with depth. For oxygen andcarbonates, the distributions of flux had structures similar to that of the curmt speed field.     

BIOGEOCHEMICAL MECHANISM OF POSTDEPOSITIONAL MIGRATION OF Fe AND Mn IN LAKE AHA, CHINA

I.INTRODUCTIONLakeAhaisamedium--sizedartificialreservoirwithseasonallyanoxichypolirnnion,andawaterresourceofGuizhouProvince,China,builtin1958,workedin1960andexpandedin1982.Ithasadrainagebasinof190kmZwithaverageannualtemperatureof15.3tandprecipitationof1109rum.Openplantcover,containiflgshrubandgrass,surroundsthelake,andsialliticandstfeteyellowsoilisdevelopedonPe~ianlimestoneandcoallayer,meanwhile,OThisprojectwassupportedbytheNationalNaturalaudienceFOundationofChinaandtheaudienceFOund…     

The apparent copper complexing capacity of seawater and the interaction of copper with humic matter

The anodic stripping voltammetry with physically-coating mercury film electrode was used to investigate the complexing action of trace heavy metals in seawater with organic ligands. The apparent copper complexing capacity of seawater was determined by titrating the organic ligands in natural seawater with standard ionic copper solution. The complexing actions of copper in seawater with humic acid (HA) or fulvic acid (FA) were investigated by titrating copper in seawater with HA or FA solution. The equilibrium time, electrodeposition potential, and effect of pH etc. were investigated respectively. The results show that the interaction of copper in seawater with organic matter is a fast process. At natural pH, HA or FA tend to act with copper in seawater to form nonlabile complexes. During experimental electrode process, these complexes did not significantly dissociate. The experimental results were calculated according to 1∶1 complex formation.     

Biochemical studies on “sub-micrometer particles” at Daya Bay I. Study on concentration, distribution and correlation of trace metals in different size fractions

This paper discusses the measured concentrations of trace metals in different size fractions at Daya Bay, and describes the features of distribution and variation of lead, copper and cadmium there. On average, 16% of Pb, 10% of Cu and 8% of Cd which previously would have been considered in the dissolved phase are actually associated with colloidal material. Thus, past studies overestimate the dissolved trace-metal concentration. The correlation between the colloidal fraction and the so-called dissolved fraction suggests the significant role of colloidal material in the biogeochemistry of trace metals. Project supported by the National “Ninth-Five-Year Plan” Special Project (No.97-926-04-03) and “KZ95T-04-04-04” Fund.     

Determination of apparent sampling thickness of sea surface microlayer

IwrRODUtvIONTheseasurfacendcrolayer(SML)isathinair-seainterfacelayerwithphySical,chdricalandbiologicalproperties.OrganicmateriaIs,haceAnIs,nutrientS,particulatCrnat-terandplanktonaregenefallyenrichedintheSML(Hardy,JT.etal.,l98O,Wunams,P.M.etal.,1986).ThesamPlersforcolledingtheSMLwerernainlyglassplatespearvey,G.W.etal.,l972,l985;ZhangZhengbinetal.,l996),rotatingdrums(Harvey,G.W.,1966,Daumas,R.A.l976),screensgurmt,W.D.,l965,Piotrowicz,S.R.etal.,l972,Carison,D.J.,l982),funneIs…     

Vertical variations and composition of dissolved free amino acid in the seawater of the Yap Trench in the western Pacific Ocean

The composition and concentration of dissolved free amino acid (DFAA) of seawater samples collected in May 2016 from the surface to the hadal zone of the northern region of the Yap Trench were analyzed by pre-column derivatization of o-phthalaldehyde. Results show that the average concentration of DFAA in the study area was 0.47±0.36 µmol/L. In different sampling stations, the concentrations of DFAA with water depth showed complex variation patterns. At the sediment-seawater interface, the concentrations of DFAA in the western side of the trench were obviously higher than that in its eastern side. In the study area, there were no significant correlations between the concentrations of DFAA and the environmental parameters such as concentrations of chlorophyll a (Chl a), dissolved oxygen (DO), pH, and dissolved inorganic nitrogen (DIN), indicating that the concentrations of DFAA in seawater of the trench are affected by many factors, such as photosynthesis, respiration, temperature, pressure, illumination, and circulation. The dominant DFAA are similar in different water layers of sampling stations, including aspartic acid (Asp), glutamic acid (Glu), glycine (Gly), and serine (Ser). The composition of different amino acids, and the relative abundance of acidic, basic, and neutral amino acids might be related to the sources and consumption of various amino acids. Nine pairs of amino acids in the DFAA showed significantly positive relationship by correlation matrix analysis, suggesting that they might share similar biogeochemical processes. The degradation index (DI) of the DFAA in seawater of the Yap Trench could reflect the degradation, source, and freshness of DFAA in the trench to some extents. This is a preliminary study of amino acids from sea surface to hadal zone in the ocean, more works shall be done in different trenches to reveal their biogeochemical characteristics in extreme marine environments.

     

EVALUATION OF GEOCHEMICAL QUALITY CONTROL IN DETERMINATION OF Mn IN SOILS USING A SEQUENTIAL CHEMICAL EXTRACTION

Sequential chemical extraction procedure has been widely used to partition particulate trace metals into vari-ous fractions and to describe the distribution and the statue of trace metals in geo-environment.One sequential chemical extraction procedure was employed here to partition various fractions of Mn in soils.The experiment was designed with quality controlling concept in order to show sampling and analytical error.Experimental results obtained on duplicate analy-sis of all soil samples demonstrated that the precision was less than 10%(at 95% confidence level).The accuracy was estimated by comparing the accepted total concentration of Mn in standard reference materials (SRMs) with the measured sum of the individual fractions.The recovery of Mn from SRM1 and SRM2 was 94.1% and 98.4%,respectively.The detection limit,accuracy and precision of the sequential chemical extraction procedure were discussed in detailed.All the results suggest that the trueness of the analytical method is satisfactory.     

河南秋树湾角砾岩型铜矿特征及成矿作用

秋树湾铜钼矿床位于北秦岭造山带南侧靠近商丹断裂,铜矿赋存于北山角砾岩筒中,黄铜矿发育于角砾岩胶结物中。金属矿物简单,主要为黄铜矿、磁黄铁矿、闪锌矿和辉钼矿。矿石铅、硫同位素等表明成矿物质与深源浅成小斑岩体有关。氢氧同位素以及包裹体成分指示大气降水参与了成矿作用。铜钼矿形成于统一的接触交代成矿作用体系,后期热液使早期形成的矽卡岩发生退化蚀变并形成铜矿。     

Chemical characteristics and environmental significance of fresh snow deposition on Urumqi Glacier No. 1 of Tianshan Mountains, China

Ice and snow chemistry of alpine glaciers is crucial for the research of regional atmospheric environment change. Fresh snow samples were weekly collected from Urumqi Glacier No.1 in the Tianshan Mountains, Xin- jiang, China, and the chemical characteristics and seasonal variations of major ions, mineral dust, δ18O and trace metals were measured. Results show that the concentrations of major ions in the snow are Ca2+ SO42- NH4+ NO3- Cl- Na+ Mg2+ K+, in which Ca2+ is the dominant cation, and SO42-is the dominant anion. All major ions have close positive correlations with each other except NO3-. δ18O shows positive correlation with air temperature change during the study period. Mineral dust particle and major ionic concentrations in fresh snow have obvious seasonal change, with high concentration in spring but low concentration in summer and autumn, which indicates that the chemical mass input from Asian dust activity to snow is very significant. Temporal changes of trace metals in fresh snow, e.g., Cd, Pb, Zn, Al, Fe, have shown that human-induced pollution of central Asian region also has large contribution to the snow chemistry on alpine glaciers of the Tianshan Mountains.