Bioaccumulation of heavy metals in oyster (Crassostrea virginica) tissue and shell     

W. Huanxin  Z. Lejun  B. J. Presley 《Environmental Geology》2000,39(11):1216-1226

Oysters and sediment have been collected from most major US Gulf of Mexico bays and estuaries each year since 1986. Selected samples of oyster soft tissue, shell and sediments were analyzed for Cd, Cr, Cu, Fe, Mn, Pb, and Zn for this study. Concentrations varied considerably from place to place but ratios of metals remained relatively constant. Cu and Zn are greatly enriched in oyster tissues, which is related to their physiological function. Cd is enriched in oyster shell because of the easy substitution between Cd and Ca. The concentrations of Pb and Cr in oysters are significantly lower than that in sediment, suggesting a good discrimination against these metals by oysters. Metal variations are a result of both nature and human activity. Received: 13 September 1999 · Accepted: 8 December 1999  相似文献   

Source of pollution as a factor controlling distribution of heavy metals in bottom sediments of Chechło River (south Poland)     

D. Ciszewski 《Environmental Geology》1997,29(1-2):50-57

 The influence of sources of effluents on pollution of bottom sediments of the small Chechło River (23 km long, mean discharge 1.5 m³ s^–1) in southern Poland was examined through analysis of heavy metals distribution in transverse and longitudinal cross sections. Underground waters from a Pb–Zn mine cause very high concentrations of Zn, Cd, and Pb in both fractions investigated (<1 mm and <0.063 mm) of sediments in the active channel zone, whereas sedimentation of huge amounts of suspended matter discharged from oil refinery cause concentrations of heavy metals in fine fractions rather uniform in cross sections. In the lowest reach, with relatively reduced contamination, the highest concentration both in fine and coarse fractions occurs close to the river banks and in the deepest points of the channel. The lowest concentrations have been found at the points of strongest reworking and accumulation of sandy material in the riverbed. Received: 25 April 1995 · Accepted: 11 September 1995  相似文献   

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

张正斌刘春颖  刘莲生于琳 王肇鼎 《中国海洋湖沼学报》2004,22(1):54-63

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.  相似文献   

Suspended sediment yield and metal contamination in a river catchment affected by El Niño events and gold mining activities: the Puyango river basin,southern Ecuador     

N. H. Tarras‐Wahlberg  S. N. Lane 《水文研究》2003,17(15):3101-3123

The suspended sediment yield and the transfer of polluted sediment are investigated for the Puyango river basin in southern Ecuador. This river system receives metal (Cd, Cu, Hg, Pb and Zn) and cyanide pollution generated by mining, and is associated with large‐scale hydrological variability, which is partly governed by El Niño events. Field sampling and statistical modelling methods are used to quantify the amount of mine tailings that is discharged into the basin. Annual suspended sediment yields are estimated using a novel combination of the suspended sediment rating method and Monte Carlo simulations, which allow for propagation of the uncertainties of the calculations that lead to final load estimates. Geochemical analysis of suspended and river bed sediment is used to assess the dispersion and long‐term fate of contaminated sediment within the river catchment. Knowledge of the inter‐ and intra‐annual variation in suspended sediment yield is shown to be crucial for judging the importance of mining discharges, and the extent to which the resultant pollution is diluted by river flows. In wet years, polluted sediments represent only a very small proportion of the yield estimates, but in dry years the proportion can be significant. Evidence shows that metal contaminated sediments are stored in the Puyango river bed during low flows. Large flood events flush this sediment periodically, both on an annual cycle associated with the rainy season, and also related to El Niño events. Therefore, environmental impacts of mining‐related discharges are more likely to be severe during dry years compared with wet years, and in the dry season rather than the wet season. The hydrological consequences of El Niño events are shown to depend upon the extent to which these events penetrate inland. It is, thus, shown that the general conclusion that El Niño events can significantly affect suspended sediment yields needs evaluation with respect to the particular way in which those events affect a given catchment. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

桓仁—宽甸地区金、有色金属成矿规律     

王文清  罗守文  邵会文 《国土资源》1993,(1)

桓仁—宽甸金、有色金属矿比集中区是华北地台北缘太平洋成矿带的重要成矿区。通过区域成矿地质背景和控矿因素的分析,划分了六种区域成矿类型及两大成矿系列,建立了区域多元成矿模式。沉积变质改造型铅锌、金、铜矿产受辽吉古裂谷含矿岩系中的特定层位控制,成矿物质来源于海底火山作用。中生代有色金属矿产受燕山晚期不同阶段特定岩性控制,第一阶段受张剪性断裂控制的中性、中酸性侵入岩与铜(铁)、金关系密切;第二阶段的中酸性脉岩控制部分铅锌、铜矿床;第三阶段的中酸性浅成、超浅成侵入体与铝、铅锌、铜矿有关。中寒武世地层可提供部分矿质,并成为接触交代型矿床的最佳赋矿层位。  相似文献   

Sea-surface microlayer metals enrichments in an urban and rural bay     

J.T. Hardy  C.W. Apts  E.A. Crecelius  N.S. Bloom 《Estuarine, Coastal and Shelf Science》1985,20(3):299-312

The sea-surface microlayer is an important interface between the atmosphere and ocean and a collection point for many anthropogenic materials including potentially toxic metals. We developed a glass plate sampler to collect the upper 30 to 55 micrometers of the sea surface. Samples of the microlayer and subsurface bulk water from an urban and rural bay were analysed for concentrations of Pb, Zn, Cu, Cd and Fe. Metal concentrations in both the microlayer and bulk water were generally 2 to 15 times greater in the urban than in the rural bay. Concentrations of metals in the microlayer of both bays averaged 6 to 65 times greater than those in the bulk water. In the urban bay, microlayer concentrations of Pb, Zn and Cu from 10 to > 100 μg 1^?1 were common. Measured microlayer metals concentrations agree well with those predicted from atmospheric deposition rates using a previously derived empirical model developed from laboratory microcosm studies. Further work will be required to determine whether or not these high microlayer metal concentrations contain significant biologically available fractions which could impact fisheries recruitment of larval icthyoneuston.  相似文献   

Global trace metal cycles and predictions     

Fred T. Mackenzie  Ronald J. Lantzy  Virginia Paterson 《Mathematical Geology》1979,11(2):99-142

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沉积物暴露条件下文蛤Meretrix meretrix 对重金属Cu、Pb的富集动力学研究          下载免费PDF全文

李磊  王云龙  沈盎绿  蒋玫  黄厚见  沈新强 《热带海洋学报》2013,32(1):70-75

应用半静态双箱动力学模型室内模拟了沉积物暴露条件下文蛤Meretrix meretrix 对Cu、Pb的生物富集,通过对富集与排出过程中文蛤体内重金属污染物的动态监测和对富集与排出过程监测结果的非线性拟合,得到了文蛤富集重金属的吸收速率常数K₁、排出速率常数K₂、生物富集因子BCF(bioconcentration factors)、生物学半衰期B_1/2等动力学参数。拟合结果得到的Cu、Pb各动力学参数分别为,K₁为4.6333—72.3754;K₂为0.0512—0.0798;BCF为60.7646—1414.9634;B_1/2为8.69—13.55。对模型的拟合优度检验结果显示,沉积物暴露条件下文蛤对重金属Cu、Pb的生物富集数据符合双箱模型,模型的拟合优度良好。比较结果得出,吸收速率常数K₁及生物富集因子BCF均随着外部水体金属暴露浓度的增大而减小;文蛤对Cu富集能力大于Pb;Cu在文蛤体内的生物学半衰期B_1/2大于Pb;理论平衡状态下生物体内Cu、Pb的含量C_Amax随着外部水体中金属暴露浓度的增大而增大,且呈显著正相关,实验结果表明沉积物暴露条件下双箱动力学模型在一定条件下是可以应用于文蛤的富集动力学研究的,仍需要进一步开展不同条件下实验研究分析。  相似文献   

Increased Particle Fluxes at the INDEX Site Attributable to Simulated Benthic Disturbance     

G. Parthiban 《Marine Georesources & Geotechnology》2013,31(3):223-235

Abstract

Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m^?2 day^?1. Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (～4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ～5 days showed a reduction in particle fluxes of ～50%, indicating rapid particle settlement.  相似文献   

New Notodelphyidae (Copepoda: Cyclopoida) from solitary ascidians     

J. B. Jones 《新西兰海洋与淡水研究杂志》2013,47(2):255-273

Samples of simple ascidians of the genera Asterocarpa, Cnemidocarpa, Corella, and Pyura were collected from Wellington Harbour, New Zealand (41°16'S, 174° 51'E) and three species of the crustacean family Notodelphyidae were recovered, all from the branchial baskets of the ascidians.

Pygodelphys novaeseelandiae (Schellenberg), and two new species of Doropygus, are described and illustrated.  相似文献