Study on the Improvement of Sea-Entering Waterway in the Changjiang Estuary

The Changjiang Estuary is the doorway of the Shanghai Harbour and the throat for the six provinces in the Changjiang River drainage area. However the minimum water depth of the waterway in the estuary is only about six meters, so that the development of the Shanghai Harbour and the utilization of water transportation on the Changjiang River have been greatly restrained. Since 1975, the depth of the sea-entering waterway of the Changjiang Estuary has been successfully increased by one meter. This article has made a comprehensive summing-up about the selection of waterways, the determination of the line for dredging and disposal of the dredged material, thus providing reference data for future work in increasing the depth of the waterway of the Changjiang Estuary and for controlling similar waterways of other estuaries.     

Grey Prediction of Siltation in North Channel of Yangtze Estuary

-The North Channel in the Yangtze Estuary is one of sea-leading waterways of Shanghai Harbour, in which yearly dredging volume reaches over ten million cubic meters, and it tends to increase year by year. Based on the channel regime similarity and through the relational grade, a GM (2, 1) is set up. It reveals the course of development of channel regime similarity under the action of various factors, and predicts the siltation volume in the nearest future which is the basis of dredging planning for relevant dredging departments.     

Harmonious Development of Utilization and Protection of Tidal Flats and Wetlands-A Case Study in Shanghai Area

Spatial, environmental, and material resources are important for tidal flats and wetlands, thus, a harmonious balance between utilization and protection should be maintained. In the present study, the concept of tidal flat is defined, and its spatial limitation is also clarified. Located at the Yangtze Estuary, tidal flats in Shanghai area are selected for study. The relationship between water discharge and sediment transport of the Yangtze River, allowed exploration intensity and needs for wetland protection are discussed in the paper. The dynamic process and changing trend for different types of tidal flats are illustrated in detail. Regulations are proposed for a reasonable exploitation, dynamic protection, and ecosystem restoration of each individual tidal fiat and wetland. Some valuable suggestions are put forward for further study about the sustain＇able exploitation of offshore resources in Shanghai area.     

New Eulerian-Lagrangian Method for Salinity Calculation

A difference scheme in curvilinear coordinates is put forward for calculation of salinity in estuaries and coastal waters, which is based on Eulerian-Lagrangian method. It combines first-order and second-order Lagrangian interpolation to reduce numerical dispersion and oscillation. And the length of the curvilinear grid is also considered in the interpolation. Then the scheme is used in estuary, coast and ocean model, and several numerical experiments for the Yangtze Estuary and the Hangzhou Bay are conducted to test it. These experiments show that it is suitable for simulations of salinity in estuaries and coastal waters with the models using curvilinear coordinates.     

Mechanism of the Impact of Floods and Typhoons on the Morphological Evolution of the Yangtze Estuary

In the last two decades,the Yangtze Estuary has undergone significant changes under the influence of reduced sediment inflow and estuary engineering.This study investigates the influence of floods and typhoons on sediment concentration and the morphological evolution of shoals and channels in the Yangtze Estuary.The analysis is conducted through the utilization of topographic data measured pre-and post-flood events and observations of hydro-sedimentary changes during typhoons.By using a generali...     

Impact of estuarine reclamation projects on saltwater intrusion and freshwater resource

Estuarine projects can change local topography and influence water transport and saltwater intrusion.The Changjiang(Yangtze) River estuary is a multichannel estuary,and four major reclamation projects have been implemented in the Changjiang River estuary in recent years:the Xincun Shoal reclamation project(RP-XCS),the Qingcao Shoal reclamation project(RP-QCS),the Eastern Hengsha Shoal reclamation project(RP-EHS),and the Nanhui Shoal reclamation project(RP-NHS).The effects of the four reclamation...     

Simulation of Typhoon-Driven Waves in the Yangtze Estuary with Multiple-Nested Wave Models

Typhoon-generated waves are simulated with two numerical wave models, the SWAN model for the coastal and Yangtze Estuary domain, nested within the WAVEWATCHIII （WW3） for the basin-scale East China Sea domain. Typhoon No. 8114 is chosen because it was very strong, and generated high waves in the Estuary. WW3 was implemented for the East China Sea coarse-resolution computational domain, to simulate the waves over a large spatial scale and provide boundary conditions for SWAN model simulations, implemented on a fine-resolution nested domain for the Yangtze Estuary area. The Takahashi wind model is applied to the simulation of the East China Sea scale （3-hourly） and Yangtze Estuary scale （1-hourly） winds. Simulations of significant wave heights in the East China Sea show that the highest waves are on the right side of the storm track, and maxima tend to occur at the eastern deep-water open boundary of the Yangtze Estuary. In the Yangtze Estuary, incoming swell is dominant over locally generated waves before the typhoon approaches the Estuary. As the typhoon approaches the Estuary, wind waves and swell coexist, and the wave direction is mainly influenced by the swell direction and the complex topography.     

Simulation of Suspended Sediment in the Yellow and East China Seas

Described is an initial attempt to simulate the suspended sediment dynamics relating to tidal and wave forcing during summertime in June 1980 and August 1981 for the Yellow and East China Seas continental shelf. The cohesive/non-cohesive sediment resuspension and movement generated by the interaction between current and wave are modeled by use of ECOMSED and WAM Cycle 4. Model results are compared with observations in US-China Marine Sedimentation Dynamics Program performed for 1980-81 at off the Changiiang estuary. The main features of simulations show that suspended sediment concentrations during the summer decreased markedly offshore as observed during the simulation periods. As for some discrepancies for the mouth of the estuary with high river discharges, i.e., the Changjiang River, the model did not properly reproduce the over-mixing situation in the summer; thus distinct vertical concentration variation in this local region is not agreeable with observation. However, general dispersal patterns of suspended sediment movement seem to be agreeably reproduced for the nearshore shallow region. Some of the procedures of simulation and results are presented and discussed.     

Accumulation and Cycle of Heavy Metals in Sonneratia apetala and S. caseolaris Mangrove Community at Futian of Shenzhen, China

Wetland ecosystem in the Shenzhen Bay is one of the internationally important ecosystems in South China Region. Its core, with the Mai Po Mangrove Nature Reserve in Hong Kong on the one side and the Futian Mangrove Nature Reserve in Shenzhen on the other side, provides habitats for many rare and endangered wild birds, especially for migratory birds[1, 2]. With the economic development in Hong Kong and Shenzhen, a large mount of silt and untreated waste water are poured into the Shenzhe…     

RESEARCH ON GUARANTEED WATER DEPTH FOR SAFE DRAINING AT ZUYUAN SEWAGE OUTLET

To select the location of sewage outlet in the sewage disposal program of Shanghai is a rather comprehensive problem which covers many fields and has great influences. The sewage outlet at Zuyuan, about 10 km away from Wusongkou, is situated on the south bank of the South Channel in the Yangtze Estuary. In order to determine the water depth which can guaranteed the safe draining of sewage at the outlet, a statistical method is adopted in this paper for the determination of the guarantee rate of safe draining at Zuyuan sewage outlet by means of the characteristics of fluvial process and previous topographic data, and the guaranteed water depth for safe draining is then determined.     

长江口外表层沉积物黏土矿物分布特征（英文）

依据对长江口外表层沉积物187个站位沉积物样品的黏土矿物含量分析,研究了长江口外表层沉积物黏土矿物的组合特征和分布规律。长江口外表层沉积物伊利石为优势矿物,平均含量为60.3%;次之为蒙脱石,平均为14.9%;高龄石平均含量13.5%,绿泥石平均含量为12.3%。黏土矿物的组合类型以伊利石-蒙脱石-高岭石-绿泥石型为主,伊利石-高岭石-绿泥石-蒙脱石型次之;长江口外表层沉积物黏土矿物主要为陆源成因,物质主要来源于黄河和长江的供给。Q型聚类分析显示,现代黄河物质及老黄河物质主要沉积于研究区东北部北纬29°30′以北地区,长江物质主要在研究区西部及中部区域沉积。     

Organic contaminant distributions in sediments, polychaetes (Nereis virens) and American lobster (Homarus americanus) from a laboratory food chain experiment.

A laboratory experiment was conducted to investigate the transfer of organic contaminants from an environmentally contaminated marine sediment through a simple marine food chain. The infaunal polychaete, Nereis virens, was exposed to contaminated sediment collected from the Passaic River, NJ, USA, for 70 days. These polychaetes were then fed to the American lobster, Homarus americanus, for up to 112 days. Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), 2,4,6,8-tetrachlorodibenzothiophene (TCDT), polychlorinated biphenyls (PCBs), and several chlorinated pesticides were accumulated by polychaetes following exposure to the contaminated sediment. Some of these contaminants were also accumulated by lobsters which were exposed to the contaminated sediment and/or fed contaminated polychaetes. Only the lesser chlorinated PCDDs and PCDFs (mostly tetra- and pentachlorinated congeners) and 2,4,6,8-TCDT were detected in the polychaetes and lobster. Significant alterations were noted in the PCB patterns found in both species, particularly the lobster. The non-ortho-substituted PCBs (such as congeners 77 and 126) became enriched in the PCB mixtures of the polychaetes and especially the lobsters relative to the sediment, probably because these congeners were not metabolized. These congeners and the 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity equivalents of the PCB mixtures were enriched by a factor of about six in the lobsters relative to the sediment. Elimination of PCB congeners containing vicinal hydrogens in the meta-para region is consistent with cytochrome P450IIB-type metabolism. Based on the concentration trends for some PCB congeners and chlorinated pesticide ratios measured in the lobsters during this experiment, it appears that this metabolic system is inducible in the American lobster.     

Trends in the spatial and temporal distribution of metals (Cd,Cu, Zn and Pb) and organic compounds (PCBs and PAHs) in Dutch coastal zone sediments from 1981 to 1996: a model case study for Cd and PCBs

The spatial and temporal distribution of trace metals (Cd, Pb, Zn and Cu), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) was studied to assess trends in the sediment of the Dutch coastal zone (<63-μm fraction) from 1981 to 1996. In general, the distributions showed a distinct zonation, with highest concentrations close to the coast near freshwater outlets and where dredged material had been dumped. Over time, the zone with high concentrations narrowed and moved towards the coast. The median of the percentage of the <63-μm fraction in the surface sediments did not change significantly in the Dutch coastal zone between 1981 and 1996. In that period, the median concentrations of Cd, Cu, Zn and Pb fell by 71, 38, 49 and 53%, respectively, in the area close to the coast (<20 km) north of the outlet of the Rhine. South of this outlet the median Cd, Cu and Zn concentrations fell by 45, 29 and 17%, respectively, and in the open sea area (>20 km offshore) the median concentrations for Cu and Zn fell by 35 and 18%, respectively. The largest reduction (80%) of the median concentration of PCBs occurred in the surface sediment in the open sea area (>20 km offshore) between 1986 and 1996. During this period the median PCBs concentration fell by nearly 70% close to the coast. The median PAH concentration fell by only 26% north of the outlet of the Rhine (<20 km from the coast) between 1986 and 1996. In the other areas there was no significant change. Possible reasons are that the main sources of PAHs are in the North Sea itself and that the load of PAHs from dredged material dumped in the Dutch coastal zone increased during the period studied. The reduction of the concentrations of metals and organic micropollutants in the surface sediments of the Dutch coastal zone is explained by a conservative physical mixing model, in which the previously polluted silt fraction in the surface sediments is replaced by less polluted suspended matter. There is a time lag of several years between the trend in the load of Cd and PCBs and the observed field concentration. The half life of the silt fraction and associated substances in the surface sediments is 1.9. Taking the uncertainties in the loads into account, the calculated surface sediment concentrations for Cd and PCBs agree fairly well with the field measurements. It is concluded that there are three main reasons for the decline in the metal, PCB and PAH concentrations in the highly dynamic surface sediments of the Dutch coastal zone: (1) the decrease in the load from various sources; (2) the sedimentation and mixing of less polluted suspended matter into the active sediment layer; and (3) the washing out of previously deposited more heavily polluted particles.     

2015年春季长江口表层沉积物生源要素分布和来源

根据2015年5月对长江口及其邻近海域的生态环境调查资料, 探讨长江口春季表层沉积物总有机碳(TOC)、总氮(TN)、总磷(TP)和生源硅(BSi)4类生源要素的空间分布和来源。结果表明: 2015年春季长江口表层沉积物TOC、TN、TP和BSi平均含量分别为0.315%、0.041%、0.066%和0.450%, 其中, 沉积物中TOC、TN受到陆源输入和海洋自生输入双重影响, 且海洋自生组分的贡献较大, 二者空间分布均呈现南部分布最高并沿西北方向递减趋势; TP分布主要受陆源输入影响, 并呈西北向东南递减趋势; BSi来源于生物沉积, 总体呈现南部高、北部低的分布趋势。与2007年相比, 长江口表层沉积物有机碳、氮含量降低, 东南外海区域替代浑浊区域成为表层沉积物生源要素含量最高区域, 且陆源输入对长江口表层沉积物生源要素的贡献趋于减弱。     

Micropollutants and organic carbon concentrations in surface and deep sediments in the Tunisian coast near the city of Sousse.

A radioactive tracer was used to map the plume of the effluent of a municipal water treatment plant located on the Tunisian coast, close to the city of Sousse. A sampling campaign was programmed on the basis of the radioactivity distribution. The extent of sediment contamination was investigated to determine the impact of the plant effluent. Organic carbon and organic micropollutants (PCBs and chlorinated pesticides) were analysed on resuspendable particulate matter, on grab and core sediments. The area distributions of different compounds analysed were studied and relationships were investigated between radioactivity and organic carbon and micropollutant data. The study shows that sludge particles are deposited and accumulate in the zone south of the effluent outlet, contaminating sediments. Good correlations were found which demonstrate the efficiency of the technique used to plan the sampling and the link between organic carbon and organic micropollutants.     

秋季长江口水体颗粒有机碳年际变化及影响因素分析

根据2007—2012年长江口及其邻近海域4个航次(11月)调查资料,探讨了长江口秋季颗粒有机碳(POC)时空分布特征;结合长江口环境要素和陆源输入(径流、输沙),分析了秋季POC分布的主要影响因素。结果表明:(1)2007—2012年秋季长江口POC浓度范围为0.03—16.95mg/L,均值2.30mg/L,底层POC浓度高于表层。长江口表层POC浓度存在显著的年际变化特征。(2)长江口区POC分布呈现沿长江径流入海方向降低的趋势,高值区出现在口门附近偏南部水域。口门内和近岸水域POC显著高于近海水域。口门水域POC年际间相对稳定,近岸和近海水域年际变化显著。(3)长江口POC分布与盐度呈非保守性变化,悬浮物是POC分布的主要控制因素,多数年份POC与叶绿素a相关程度较弱。(4)河口来水来沙量对POC浓度具有较强的制约性,径流的主要影响区域在口门内和近岸区,输沙的主要影响区域在最大浑浊带和长江口北部水域。(5)入海输沙量与长江口水域POC相关性最强。咸淡水交汇引起的悬浮物沉积和沉积物的再悬浮强度决定口门内水域POC浓度,浑浊度较高的近岸水体POC对陆源输入泥沙的依赖性较强,长江口外侧海域初级生产力水平成为POC浓度的重要影响因素。     

长江口及其邻近海域表层沉积物中重金属分布和潜在生态危害评价

对长江口及其邻近海域表层沉积物中重金属Cu、Mn、Pb、Zn、Cr、Fe、Hg、Cd的含量分布以及富集状况进行分析,并采用Hakanson潜在生态危害指数法评价该海域中Cu、Pb、Zn、Cr、Hg、Cd污染的程度及其潜在的生态危害,结果表明:长江口及其邻近海域表层沉积物中Cu、Mn、Pb、Zn、Cr、Fe的分布特征表现为由近岸向远岸递减的趋势,整体上象山县和舟山群岛近岸海域的含量高于研究区北部含量;Hg在长江口南端含量较高,呈由西向东递减的趋势;Cd在长江口南端以及象山县东含量较高,在研究区中部含量较低。潜在生态危害评价结果表明,长江口及其邻近海域表层沉积物只有部分站点处于生态危害的中等级别,大多站点生态危害轻微,污染程度顺序为Cd>Hg>Cu>Pb>Cr>Zn;对长江口及其邻近海域生态环境具有潜在影响的重金属元素首先是Cd,其次是Hg。对底质环境质量进行系统聚类分析结果显示,象山县和长江口外以及济州岛西南近海海域的底质环境较差,应予以重视。     

226Ra and 228Ra in the mixing zones of the Pee Dee River-Winyah Bay,Yangtze River and Delaware Bay Estuaries

²²⁶Ra and ²²⁸Ra have non-conservative excess concentrations in the mixing zones of the Pee Dee River-Winyah Bay estuary, the Yangtze River estuary, and the Delaware Bay estuary. Laboratory experiments, using Pee Dee River sediment, indicate desorption of ²²⁶Ra to increase with increasing salinities up to 20‰. In Winyah Bay desorption from river-borne sediments could contribute almost all of the increases for both isotopes. Desorption adds only a portion of the excess ²²⁸Ra measured in the Yangtse River and adjacent Shelf waters and Delaware Bay. In the Yangtze River the mixing zone extends over a considerable portion of the Continental Shelf where ²²⁸Ra is added to the water column by diffusion from bottom sediments, while ²²⁶Ra concentrations decrease from dilution. Diffusion of ²²⁸Ra from bottom sediments in Delaware Bay primarily occurs in the upper part of the bay (< 22‰ water) where fine grained sediments predominate. A diffusive flux for ²²⁸Ra of 0·33 dpm cm^?2 year was determined for Delaware Bay.     

东湖水体中多氯联苯的研究

于1994年6月,采用高分子多孔聚合树脂对武汉东湖水进行富集采样,样品经净化后利用毛细管柱色谱进行多氯联苯（PCBs）总量及同类物（congeners）的分离测定。结果表明,东湖水样中PCBs总含量为2．7ng／L,检出的20多个PCBs同类物其含量分别在0．002－1．12ng／L范围内。其同类物中低氯取代的PCBs相对含量明显高于工业用商品PCBs中的相应含量。