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This review paper provides a brief review on the development of ideas in the fields of the sea level change of the ECS (East China Sea), the history of the Yangtze River entering the sea and paleochannels in the shelf of the ECS since the Last Glacial Maximum (LGM). The paper summarizes two opposite theories about the Yangtze River entering the sea during the LGM. One theory is that the Yangtze River input a lacustrine in the north of Jiangsu province which was defunct in middle Holocene, and the river was once dry. The other was that the Yangtze River still existed and entered into the Okinawa Trough during the LGM, but scholars share different opinions on which course the river ran across and which place the river input the trough. This paper concludes future work is to study the evolution of the Yangtze River and the paleoclimate and the corresponding events as a whole from the view of regional and even global change, and more attention should be paid to the study on mud sediment, the Yangtze River's response to the changes in climate and sea-level, and the channel metamorphosis. [ABSTRACT FROM AUTHOR]

Residues of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) and their environmental risks in surface sediments collected from the rivers and lakes in Yangtze River Catchment of Wuhan, China, are investigated in this paper. Based on dry weight (dw), the concentrations of ΣHCH ( α-, β-, and γ-HCH) and ΣDDT ( p p′-DDT, o p′-DDT, p p′-DDE, p p′-DDD) in sediments ranged from 0.10 to 21.10 ng g−1 (mean, 4.03 ng g−1 dw) and 0.79 to 35.61 ng g−1 dw (average, 6.93 ng g−1 dw), respectively. Compared with some published guideline values of organochlorine pesticides (OCPs) in sediments, the concentrations of HCHs were at safe levels while the DDT residues would pose adverse biological effects in this studied catchment. The distribution of OCPs in sediments indicated that the input of tributaries was an important factor for OCP residues in the mainstream of the Yangtze River. Levels of OCPs in the sediments were influenced by total organic carbon contents, clay contents, water contents, and pH values of sediments. The present study suggested that historical usage of technical HCH and DDT was the main reason for OCP residues in the sediments from both rivers and lakes. Furthermore, the composition of OCPs reflected additional sources of the holding usage of lindane and fresh inputs of dicofol mixture in this region. [ABSTRACT FROM AUTHOR]

A model has been created for calculating the balanced diversion ratios of flow rate and sediment in the branches of a bifurcated river. The model is based on the extremity law of energy dissipation rate, and involves solving the simultaneous equations of flow and sediment motion for uniform flow in an open channel. The model has been verified by measured data obtained from the Meizizhou and Baguazhou branches of the Yangtze River in China. The parameters that influence the diversion ratios, such as river width, channel roughness and the total inflow, have been analysed. It was found that balanced diversion ratios are more sensitive to river width and roughness than to total inflow. Measures to regulate the Baguazhou branch have been compared further and analysed. The conclusions of this study can provide a theoretical basis for future regulation of the Baguazhou river branch. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports the initial result of the flux of submarine groundwater discharge (SGD) into the Changjiang effluent plume (CEP). A radium mass balance model and a 224Ra/223Ra activity ratio (AR) apparent age model were applied to estimate the residence time of water above the pycnocline in the CEP. These two approaches gave similar results, yielding residence times of 5.4d and 7.0d, respectively, in the inner and outer plume zones. The nonconservative inventory of 226Ra was established in the CEP, and converted to a 226Ra flux by dividing by the water residence time and assuming steady state conditions. After subtracting the desorption of 226Ra from suspended sediment and the diffusion from the bottom sediment, the 226Ra flux from SGD was converted to a total SGD flux by dividing by the measured activity of 226Ra in local groundwater. The SGD flux in the CEP is estimated to be 0.2–1.0×109 m3 d−1, which is equivalent to 6–30% of the Changjiang water discharge during flood season. This large flux indicates that SGD may be another important nutrient source to the East China Sea. [Copyright &y& Elsevier]

Abstract: This paper examines the spatial variation of sediment yield in the Yangtze basin in China, a large basin with complex geology, climate, land-use history, and extensive sediment monitoring. 287 stations with drainage area less than 10,000km2 were used to study the scale effects of sediment yield. In order to develop scale relations for regional sediment yield, the whole study area was divided into eight sub-basins. Relation between specific sediment yield and drainage basin area was built for each sub-basin. Regional scaling relation was analyzed based on landforms, geology, lithology and land-use of each sub-basin. Three regional trends were identified in relation to the drainage area: (1) a declining trend, due to soil erosion on heavily cultivated steep land and the storage of sediment in floodplains; (2) a flat trend, due to mass movement on the upper reach and heavy agricultural disturbance on the middle and lower reaches; and (3) an increasing trend, due to downstream recruitment of sediment from land downstream where slope farming and deforestation occurred. Using these developed relations, areally adjusted sediment yield maps were created over the entire Yangtze basin. [Copyright &y& Elsevier]

Abstract: Heavy metal contamination of bottom sediments of the Changjiang River is widely reported, however, the potential source and methods of transportation of these heavy metals in the contaminated sediments is poorly defined. This paper examines the correlation between heavy metals and geochemical indices, including Fe2O3, Al2O3, total organic carbon (TOC) and black carbon (BC), as well as magnetic susceptibility (MS). Using these indices we investigate the contamination characteristics of heavy metals in the sediments by with Principal Component Analysis (PCA). Results from 83 sediment samples collected in the lower reach of Changjiang River (from Nanjing to Shanghai) show that the first principal component accounts for 52.23% of the total variance, corresponding to the heavy metals, Co, Cr, Cu, Ni and Zn, and conservative components of Fe2O3, Al2O3 and TOC. This result indicates that heavy metal distributions are controlled by the transportation and sedimentation of fine particles which is also confirmed by particle size analysis. The second principal component explains 24.81% of the variance and is dominated by Cd, Pb and MS, which, collectively, result chiefly from industrial and transportation activities and, for MS, fly ash production. The third principal component accounts for 7.91% of the variance and corresponds solely to Hg. Principal component analysis/multiple linear regression (PCA/MLR) was used to estimate the contribution of the three principal components to each heavy metal. PCA/MLR results suggest that more than 50% of Co, Cr, Cu, Ni and Zn were influenced by the particle size effect. Particle size effect and fly ash account for 37.1% and 27.7% of As. Cd and Pb were mainly explained by fly ash. 98.9% of Hg was related to PC3, which represented black carbon (BC). Our study indicates that the combination of geochemical and multivariable statistical methods clearly characterizes the geochemistry of heavy metals in sediment of the lower reaches of the Changjiang River and suggests that power plants are the main source of heavy metal pollution. [Copyright &y& Elsevier]

Abstract: Matrix bound phosphine (MBP) is commonly considered an important phosphorus form in the natural environment. This paper presents an investigation of the spatial distribution of MBP and its relationship with the environmental factors in the Changjiang Estuary and its adjacent shelf areas (29.5–32°N, 122–124°E). A total of 32 surface sediment samples were collected from April 24 to 30, 2008. MBP was detected in all samples from the Changjiang Estuary and its adjacent shelf surface sediments (0.1–29.7 ng kg−1). The concentration of MBP decreased from the Changjiang Estuary to the East China Sea shelf. Environmental factors such as organic matter, type of sediments, and redox conditions were found to affect the concentration and distribution of MBP in the marine sediments. Although the MBP levels were low in the marine sediments, the marine biogeochemical cycles of MBP in sediments were established and the information presented here will contribute to the understanding of the biogeochemical cycle of phosphorus. [ABSTRACT FROM AUTHOR]

Abstract: Floods often are accompanied by intensified soil erosion and thus high sediment supply from the catchment into the main channel of the river. This paper examined the sediment processes, especially deposition and erosion, during the two extreme flood years in 1954 and 1998, in the middle and low reaches of the Yangtze River. The total amount of sediment supplied to the middle and lower reaches from Yichang–Hankou and Hankou–Datong, was 1095 Mt in 1954 and 855.9 Mt in 1998, or 176% and 137% of the averaged 622 Mt/a from 1950 to 2006. A high deposition occurred in the floodplains, lakes and channels along the section Yichang–Hankou, both in 1954 and 1998. The total deposition reached 635 Mt and 499 Mt in 1954 and 1998 or 138% and 124% of the sediment load measured at the Datong station, respectively. However, different processes in the downstream section Hankou–Datong during the two flood events were found. Severe erosion (−140 Mt) happened in 1954, but only a slight erosion occurred (−22 Mt) in 1998. Thus, the floodplains and channels in the middle and lower reaches of the Yangtze River play an important role in regulating sediment discharge during extreme flood events. The heavy deposition in the middle reaches effectively reduced the amount of sediment discharged into the river mouth and thus acted as a major depocenter in the extreme flood year. The results also suggested that the Yichang–Hankou tended to shift from a depositional section to an erosional section, whereas the Hankou–Datong changed from an erosion-dominated section to a deposition-dominated section even before the Three Gorges Reservoir infilling in 2003. It is anticipated that this tendency would be accelerated and the historical role of sediment regulation by the two reaches could eventually be changed due to the reduced sediment supply from the Upper Yangtze. [ABSTRACT FROM AUTHOR]

Abstract: This paper characterizes the distribution of phosphorus fractions and matrix-bound phosphine (MBP) in coastal surface sediments of the Southwest Yellow Sea from 2006 to 2007. Total phosphorus (TP), inorganic phosphorus (IP) and organic phosphorus (OP) concentrations (mgkg−1) range from 278±3 to 768±15, 160±1 to 653±27, and 3.42±0.05 to 267±22, respectively. MBP is a small portion of TP with values of 0.69±0.06 to 179±29ngkg−1. Phosphorus fractions and MBP are influenced strongly by riverine input and hydrodynamic conditions. High TP and MBP are found in the old Yellow River mouth and the Yangtze River mouth. OP and MBP are strongly negatively correlated to mean particle size. Significant positive correlations are found between MBP and IP and OM, suggesting that MBP production may be the microbially intermediated transformation of IP. [Copyright &y& Elsevier]

Abstract: Traditional measurements of suspended sediment concentrations (SSC) through in-situ sampling in rivers are expensive and time-consuming to perform. Thus, these methods cannot provide continuous SSC records. Although remote sensing has been used for SSC estimation, little research has been undertaken on inland rivers, especially for highly turbid rivers like the Yangtze. Previous studies have proposed Landsat TM/ETM+ Band 4 as a spectral SSC indicator for the Yangtze, but its limitation on temporal resolution is insufficient for the study of dynamic changes of sediment. This paper presents a method of estimating SSC of the Yangtze at Jiujiang using time-series satellite data of high temporal resolution Terra MODIS. It was found that differences in water reflectance between Band 2 and Band 5 could provide relatively accurate SSC estimation even when in-situ atmospheric conditions were unknown. After cross-validation, mean absolute relative error (ARE) and relative root mean square error (RRMSE) were relatively low (i.e., 25.5% and 36.5%, respectively). This empirical relationship was successfully applied to the estimation of SSC at Datong in the Lower Yangtze River, although the SSC values were generally underestimated. This study suggests that Terra MODIS could be used to estimate SSC in large turbid rivers, although some influencing factors require further study to improve the accuracy of SSC estimation. [Copyright &y& Elsevier]

Abstract: The adsorption of phosphorus (P) on four sediment samples (CunTan, XiaoJiang, DaNing and XiangXi) from the Three-Gorges Reservoir on the Yangtze River in China was studied systematically in batch experiments. A sequential chemical extraction experiment was conducted to clarify the effect of sediment composition on P adsorption. The results showed that P adsorption on four sediment samples mainly occurred within 6h. P adsorption kinetics can be satisfactorily fitted by both power function and simple Elovich model. A modified Langmuir model may describe well the P adsorption on all the samples in our study. Theoretically, the maximum adsorption amount (Q max) was 0.402mg-P/g for XiaoJiang sediment, 0.358mg-P/g for DaNing sediment, 0.165mg-P/g for CunTan sediment, and 0.15mg-P/g for XiangXi sediment. The sediment compositions such as organic matter, metal hydroxides, calcium and clay content showed influences on the P adsorption. Wherein, organic matter and metal hydroxides were the main factors affecting the P adsorption. The maximum P adsorption capacity (Q max) enhanced with the increase of the content of (Fe+Al+Ca). Compared the zero-equilibrium P concentration (EPC0) values obtained by the modified Langmuir models with actual P concentrations in water, all the sediments studied in this paper except for XiaoJiang showed a trend of releasing P as a source role, which could enhance the risk of eutrophication occurrence in the Three-Gorges Reservoir. [Copyright &y& Elsevier]

Summary: Annual runoff and annual suspended sediment loads of hydrological gauging stations along the mainstream of the Yangtze River basin (Pingshan station, Yichang station, Hankou station and Datong station) and main tributaries (Beipei station in Jialingjiang River, Wulong station in Wujiang River and Huangzhuang station in Hanjiang River) were analyzed with the help of Mann–Kendall trend analysis and linear regression analysis. Research results indicate that (1) changing patterns of runoff and sediment loads are different in different parts of the Yangtze River basin. No significant trend is detected for annual runoff at all stations at >95% confidence level. Changes of sediment loads, however, demonstrate different pictures in the Yangtze River basin. The sediment loads are in increasing trend in Pingshan station- the most upstream station on the Yangtze River basin (this increasing trend is significant at >95% confidence level after about 1990), but are in decreasing trend at other stations (including stations in the tributaries studied in this paper). This decreasing trend becomes more obvious from Yichang station to Datong station. (2) Water reservoirs exerted more influences on changes of sediment loads than on runoff, which is the main reason for the decreasing trend of sediment loads found in most stations. (3) Influences of water reservoirs on sediment loads are more obvious in the tributaries than in the mainstream of the Yangtze River basin, while in the mainstream the variation patterns of sediment loads are determined by multiple factors. [Copyright &y& Elsevier]

The content levels, distribution characteristics, and health risks associated with 15 rare earth elements (REEs) in urban street dust from an industrial city, Zhuzhou, in central China were investigated. The total REE content (∑REE) ranged from 66.1 to 237.4 mg kg, with an average of 115.9 mg kg, which is lower than that of Chinese background soil and Yangtze river sediment. Average content of the individual REE in street dust decreased in the order Ce > La > Nd > Y > Pr > Sm > Gd > Dy > Er > Yb > Eu > Ho > Tb > Tm > Lu. The chondrite-normalized REE pattern indicated light REE (LREE) enrichment, a relatively steep LREE trend, heavy REE (HREE) depletion, a flat HREE trend, a Eu-negative anomaly and a Ce-positive anomaly. Foremost heavy local soil and to less degree anthropogenic pollution are the main sources of REE present in street dust. Health risk associated with the exposure of REE in street dust was assessed based on the carcinogenic and non-carcinogenic effect and lifetime average daily dose. The obtained cancer and non-cancer risk values prompt for no augmented health hazard. However, children had greater health risks than that of adults. [ABSTRACT FROM AUTHOR]

This study examines the effects of hydrologic sorting and mixing of sources on the Sr-Nd isotopic compositions of suspended sediments at different water depths. The samples were collected from three layers (surface, middle and bottom) at Datong hydrological station of Yangtze River during the flood season of 2010. Our results show that, Sr/Sr values decrease from surface to bottom, ranging from 0.730332 to 0.720857. ɛ(0) values range from −14.75 to −10.09, with surface sediments being the most negative. The isotope composition at the middle layer can best represent the mean isotopic composition of the total suspended sediments transported by a river. It is believed that the stratification of Sr-Nd isotope is attributable to mixing of sediments from different sources due to hydrological sorting. Sediments from the upper stream are found to be coarser, and tend to contribute more to the lower water column. Although Sr-Nd isotope is a well acknowledged tool to trace sediment provenance, the current study suggests that the grain size of the samples and the sampling locations should be taken into consideration when applying this method to provenance study. [ABSTRACT FROM AUTHOR]

At the South Branch of the Changjiang Estuary near Baimao Shoal, two in situ approaches were used to estimate the settling velocity, ws, of suspended, fine-grained sediments. The first approach was used when the current was less than 1.5 m/s and was based on measurements from an optical backscatter sensor (OBS-3A) and a laser in situ scattering and transmissometer (LISST-100, Type C). A modification, using the measured ratio of volume concentration for each floc size class to the total volume concentration as a weighting factor. To improve a previously published approach, a better algorthim was implemented to estimate ws. Results of the modified approach (0.4 to 4.6 mm/s) are about twice those of the original approach, which assumes that all sizes of flocs have the same floc density. The second approach used the Rouse equation to estimate the depth-averaged ws when the current was strong and nearly steady around maximum ebb. Results from the second approach show a much greater depth-averaged ws (4-8.5 mm/s). This is attributed to the large bed shear stresses (between 3 and 3.6 Pa) bringing large sediments into the water column. [ABSTRACT FROM AUTHOR]

Detrital zircon grains of Late Cenozoic sediments dated back to ca. 3.6 Ma from core DY03 in the Yangtze delta were dated by LA-ICP-MS, in order to investigate the sedimentary provenance and to find some clue for the evolution of the Yangtze River. Most of the detrital zircon U-Pb ages are distributed at 100-300 Ma, 350-550 Ma, 600-1000 Ma, 1400-2000 Ma and 2200-2800 Ma, which correspond well with the main tectonic and magmatic events in the Yangtze drainage. The detrital zircon age patterns show distinct difference between the 3 samples below 189.8 m and other 6 above 189.8 m. 43%-55% zircons in the 3 samples below 189.8 m fall within Cretaceous, while ages from 150 to 2800 Ma are distributed with no obvious peaks, which indicate the sedimentary provenance may be limited to the lower Yangtze drainage. The 6 samples above 189.8 m show similar age patterns, and the ages are relatively evenly distributed, indicating the sedimentary provenance broadened distinctly. All 6 samples deposited later than ca. 3.2 Ma show age information from the upper Yangtze drainage (including the Emeishan large igneous province), indicating that the Three Gorges may have already been cut through by then. [ABSTRACT FROM AUTHOR]

Bathymetric data based on sounding surveys and intertidal elevations measured using Real-Time Kinematic Global Positioning System methodology were analyzed using Geographical Information System techniques to examine the morphological evolution of the tidal island Jiu Duan Sha (JDS) in the Yangtze estuary. It was found that, from 1958 to 2005, the area and sediment volume of JDS increased by 96% and 156% above the 5 m isobath and by 331% and 504% above the Lowest Astronomic Tide (LAT). Specifically, the maximum elevation of the island increased from 0.3 to 4.9 m above the LAT, and the salt marsh increased from 0% to 40% of the intertidal area. The dominant factor controlling the growth of this wetland was found to have varied with time. The growth was mainly due to the deposition of riverine sediment before the 1970s but was primarily the result of the merging of a shoal into JDS between 1971 and 1994 and, later, the local engineering projects between 1994 and 2005. It was concluded that human activities are playing an increasingly important role in the morphological evolution of tidal wetlands in the Yangtze estuary. [ABSTRACT FROM AUTHOR]

Numerous landslides have occurred during the construction of the Three Gorges Reservoir of the Yangtze River. Although the underlying causal factor of these landslides was heavy rainfall, the construction process was the trigger of some of them. We report here a systematic study aimed at reconstructing the geological history of an ancient landslide and, based on our results, an evaluation of the role of the history on current landslide stability. Data from detailed field surveys and the studies on geological dating revealed that the Baiyian landslide was composed of five structural parts of different geological ages, such as a sliding belt, disturbed rocks, ancient colluvium, alluvium of the Yangtze River and slope wash. The succession of ancient climates, terraces and tectonic processes in the study area were examined from 300 ka ago. The evolutionary history of the Baiyian ancient landslide can be divided into five distinct stages: development, occurrence, deposition, collapse and disintegration. Some parts of the ancient landslide are currently prone to instability due to the combination effects of heavy rainfall and construction of the reservoir. [ABSTRACT FROM AUTHOR]

The Chinese Moderate Resolution Imaging Spectroradiometer (CMODIS) was loaded on the China's SZ‐3 spacecraft. Using an empirical line method, the CMODIS radiance is converted to the water‐leaving reflectance, and is applied to inversion of the suspended sediment concentrations in the Yangtze River estuary. The concentrations ranging between 0 mg/L and 1000 mg/L are well validated by the field measurement data. This study demonstrates an example for the feasibility of the CMODIS data for concentration retrieval of the suspended sediment. [ABSTRACT FROM AUTHOR]