Historical Records of Metal Pollution in Sediments of Toronto and Hamilton Harbours

The sediments of Hamilton and Toronto Harbours contain some of the oldest records of metal pollution in the Great Lakes basin. The fluxes of Cd, Cr, Cu, Ni, Pb, Zn, Fe, and Mn into the two harbours have been estimated from the analyses of core samples dated by the Pb-210 technique. The contrasting metal levels in the two harbour sediments are viewed in relation to the differences in the disposal strategies of the dredged spoils and the sources of metal pollution in the harbours. The Zn and Fe concentrations of 5 to 8 mg g^?1 and 10 to 13 % dry wt. in Hamilton Harbour sediments, which are among the highest recorded in any harbour, can be related to effluent discharges from the large local iron and steel plants. An inventory of the sources and sinks of pollutant metals in Hamilton Bay shows a substantive export of the metals to Lake Ontario.     

Large scale treatment of contaminated sediments in the Netherlands,the feasibility study

In The Netherlands, contaminated sediments have to be removed from waterways. Environmental policy is directed at treatment of 20% of the contaminated dredged materials, thus generating reusable materials and saving on the required capacity in large scale disposal sites. The huge volume of material that will become available annually, can only he dealt with when treatment will take place on a large scale. A feasibility study was carried out for presenting treatment alternatives and compare these on technical, environmental and organisational aspects, as well as costs and financing. This paper presents the main results of the feasibility study. Three treatment scenarios were developed, each using a different combination of treatment techniques. The treatment scenarios are compared with a reference. It is shown that all treatment scenarios can meet policy goals. Costs for large scale treatment depend on the scenario that will be selected.     

An assessment of sediment reuse for sediment management of Gallito Ciego Reservoir,Peru

Gallito Ciego Reservoir, with a surface area of 14.2 km² and mean depth of 40.3 m, is located in the Jequetepeque River basin in north‐western Peru. It is rapidly filling with sediments, endangering its main purpose of supplying agricultural irrigation water. A sediment volume corresponding to 70% of the dead water volume has accumulated in the reservoir up to 2007, with reservoir bottom outlet becoming blocked. Below the dam, 35 000 ha of irrigated cropland, supporting 115 000 habitants, are endangered. This study was conducted to evaluate the possibilities of sediment management, especially the use of the sediment for agricultural purposes in the Jequetepeque River basin. Sediment samples were collected from littoral and profound sites in the reservoir. Suspended sediments also were collected. Physical parameters were investigated, and the nutrient and heavy metal concentrations were determined. By comparing grain‐size distribution and nutrient content, as well as pollutant concentration of the sediments, to those of terrestrial soils near the reservoir, an assessment of the potential for applying the sediments on the cropland was undertaken. Texture investigations of profound sediments revealed a strong grain‐size classification within the reservoir. Because the heavy metal concentrations in the sediments were below toxic thresholds, and the concentrations of nutrients also were low, using the sediments for agricultural purposes would not constitute risks, although they cannot replace fertilizer. As a soil amendment and building material, the sediments do have an economical value. Its dredging and use, however, must be seen as only one component of more holistic sediment management of the Jequetepeque Watershed.     

Physico chemical characteristics and multivariate analysis of contaminated harbour sediments

Dredging is a very important procedure within harbour management.Italian legislation regulates dredging activity requiring high number of sampling stations and physico chemical and biological parameters but the criteria for their interpretation are not reported adequately. The comprehension of the information included in the data is a very critical step of every dredging activity of harbour sediments and the traditional examination of these large database (searching of average values of pollutants or simple correlations among pollutants) does not make easy their interpretation. So the included information can result hidden than clarified.With the aim to perform a complete characterization of the examined area we applied Principal Components Analysis (PCA) and Cluster Analysis (CA) to the examination of a complex data matrix consisting of the physico chemical characterization (sediment texture, heavy metals, organic pollutants) of the industrial canal sediments in Livorno harbour. The multivariate methods allowed to study the general distribution of pollutants in the Livorno canal, clarifying also the significant parameters for the characterization of the system.     

Heavy metals in sediments and uptake by burrowing mayflies in western Lake Erie basin

During the past two decades, burrowing Hexagenia mayflies have returned to the western basin of Lake Erie. Because of their importance as a prey resource for higher trophic levels and their extensive residence time in potentially contaminated sediment, Hexagenia may be a source of heavy metal transfer. To better understand the distribution and transfer of heavy metals in sediment and mayflies, sediment and mayfly nymphs were collected from 24 locations across the western basin of Lake Erie in May 2007. Following USEPA protocols, samples were analyzed for 16 elements using ICP-OES or ICP-MS. Metal concentrations in the sediments exceeded the Threshold Effect Level for at least one metal at all sample sites. Sediment heavy metal distribution profiles indicate metal concentrations are correlated with organic matter content, and the highest heavy metal concentrations were found in the central deeper region of the western basin where organic content in the sediments was greatest. Hexagenia were distributed throughout the western basin, with greatest density (1350/m²) within the Detroit River plume. The Cd and Zn levels in mayflies were on average approximately 4 and 2 times greater, respectively, than sediment levels, and the Cd concentrations in the sediments exceeded the Threshold Effect Level at 27 of 28 sites and exceeded the Probable Effect Level at 9 of 28 sites. Spatial representation of heavy metal concentrations in mayflies exhibited a similar pattern to the spatial distribution of heavy metals and organic matter in the sediments with higher concentrations of metals found in mayflies residing in the central deeper region of the western basin.     

Potential Sources of Asbestos in Lake Michigan

Chrysotile and amphibole mineral fibers, recognized carcinogens, have been found in Lake Michigan water. Since the sources of these fibers in Lake Michigan are unknown, a study was undertaken to determine potential sources. Information was gathered by contacting governmental agencies and reviewing literature. Two industries that used to discharge asbestos-containing effluents are located in the Lake Michigan drainage basin. Geologic deposits of mineral fibers occur in Marinette County, Wisconsin and the Upper Peninsula of Michigan. Currents and Army Corps of Engineers dredging and disposal activities were investigated as potential mechanisms of asbestos distribution in Lake Michigan. Limited environmental monitoring indicates that atmospheric loading and wash-out from numerous point and non-point sources may be an important mechanism of asbestos contamination of Lake Michigan. More environmental monitoring will be required in order to determine the relative importance of these potential sources.     

SURFIS: A tool for designing and optimizing dredging schemes

Digital Terrain Models (DTM) can be useful tools for the design and evaluation of dredging operations. Nevertheless, DTM's based on linear interpolation of data from a rectangular grid do not provide confidence intervals for unsampled locations. SURFIS is a computer program to develop DTM's that include mapped random errors for complete study areas. Contrary to other geostatistical methods it can easily be applied by non-specialists. Application of SURFIS in the Biesbosch led to significant reduction in the amounts of material that needed to be dredged. We conclude that application of SURFIS may lead to more accurate dredging operations, resulting in lower costs for removal and storage of contaminated sediments.     

黄河艾山以下河道挖泥疏浚工程断面设计初步研究

根据艾山以下河道的冲淤特性确定了挖沁疏浚的设计流量；依据实测资料建立了河槽糙率与流速的关系，并以此确定河床的糙率。从输沙能力的角度分析了断面形态对流条件的影响，选择了挖土，填土部位。通过挖泥疏浚，改变水下河槽的形式，使挟沙力达到极值，并由此建立了断面形状，尺寸所满足的驻值关系。采用迭代法求解各隐函数关系式，依次递推求得在设计流量下艾山以下河道４４个断面的几何尺寸及水流要素。计算结果表明，河道挖泥疏     

长江口深水航道疏浚土处理现状及未来展望

长江口深水航道疏浚土产生量大,但如何对其进行更好地处理是水运工程领域的一大技术难题.利用大量工程现场资料,从长江口深水航道疏浚土的基本特性出发,对比分析了疏浚土处理现状,展望了疏浚土处理的发展模式.研究表明,长江口深水航道各工程阶段的疏浚土处理模式基本适应了不同维护水深条件下的疏浚土特点,总体仍以海洋倾倒为主.但在海洋倾倒区日渐严格控制、泥沙资源供需关系日趋紧张以及滩涂湿地面临侵蚀威胁等诸多新情势下,长江口疏浚土应遵循多用少抛的处理原则,利用疏浚土吹填造地、湿地保护等多途径处置将是未来长江口深水航道疏浚土处理的发展方向.     

Pilot remediation of sediment from the Petroleum harbour in Amsterdam

The Petroleum harbour project is the third pilot remediation, which was carried out within the framework of POSW (the national development programme for treatment processes of polluted sediments). The main objectives of the pilot remediation are:

• -to demonstrate the biological treatment of dredged materials on a practical scale;
• -to gain knowledge and experience for the future remediation of the total Petroleum harbour.

A strict tender procedure was carefully executed in order to select the most effective and ‘state of the art’ biodegradation technology. The selected remediation chain was a combination of 'standard' soil treatment technology and newly developed biotechnology. The contaminated sediments were separated by hydrocyclones, then the sand fraction was cleaned by froth flotation, and the fines were treated in a continuous flow reactor consisting of a cascade of 4 bioreactor tanks. A belt press was used for dewatering the fines. Dredging, biotechnological treatment and the effects of the remediation on the environment were monitored in detail. The quality of the treated sand fraction complied with the Dutch standards for re- use and was actually applied in a project of Rijkswaterstaat. Biodegradation resulted in a substantial decrease of the oil and PAH's contents, but due to the lack of breakdown of a few high-molecular PAH's, the quality requirements of the contract were not achieved. For less heavily polluted sediments and soils the applied biotechnology may be more effective. The results of the project show that biodegradation in bioreactors on a large scale is feasible. Furthermore useful information was gathered for the future remediation of the Petroleum harbour. It is concluded that the two main objectives of the project have been attained. Finally some recommendations for the future clean-up of the Petroleum harbour are given.     

Dioxin,dioxin-like PCBs and organotin compounds in the river Elbe and the Hamburg harbour: Identification of sources

Using neural networks (in this case the Kohonen network) and a multivariate statistical method - the hierarchical cluster analysis -, a classification of dioxin data has been carried out. A principal conclusion, which can be drawn, is that a significant source of dioxin in the river Elbe, Hamburg harbour, the soils of the flood plains of the river Elbe and in soils originating from dredging materials, has been shown to originate from the dioxin contaminated region of Bitterfeld. The results indicate that the dioxin contamination in the Bitterfeld region was caused partly by metallurgy processes, not just by chemical production. Furthermore, the results show that a main dioxin source responsible for the contamination of Hamburg surface waters, not influenced by the river Elbe, is of “thermal origin”. The river Elbe shows a characteristic butyltin pattern. The cause is probably a plant in Bitterfeld. The precise sources of the dioxin-like PCB are still unknown.     

基于河流冲淤平衡理论的库区疏浚方案分析研究——以交口水库为例

陕西石川河交口水库疏浚工程量较大,水库蓄水运用后,能否确保疏浚库区不淤积是该工程成败的关键。本文根据河流冲淤平衡原理,分析论证了水库终极库容形成后的库区横断面形态,按照该横断面轮廓线以下的范围将被淤积物覆盖的原则,对原疏浚方案进行了优化,使疏浚工程量明显减少。     

Integration of sediment cleanup,waterfront redevelopment,and habitat improvements through comprehensive port planning

Ports and industrial waterfronts today face complex problems associated with environmental contamination and habitat loss that affect the ability of local governments to plan and carry out dredging and waterfront development projects. In the USA, separate regulatory programs exist to address source control, cleanup of contaminated sediments, navigational dredging projects, habitat restoration, and shoreline development projects, each with its own set of agencies, permits, and regulatory requirements. In some areas, these overlapping and often conflicting requirements and interests have led to extreme difficulties in completing port development and cleanup projects, even when these projects could have substantial benefits to the environment. This paper presents a shift in regulatory approach toward in-water projects currently being tested by the Department of Ecology and other federal, state, and local agencies in Washington State. Three projects are described that provide regulatory streamlining in exchange for integration of cleanup and habitat restoration needs into Port navigation and waterfront redevelopment projects. In addition to providing significant benefits to both navigation/commerce and the environment, substantial cost savings can be realized in comparison to traditional approaches to these projects.     

以降低洪水位为目标的河道疏浚规模与效果研究

疏浚作为一种清淤工程措施在河道治理、水库库容恢复、航道和港池维护、河湖污染物移除等方面得到广泛应用.由于担心疏浚后发生回淤,疏浚效果不能长期维持,疏浚很少作为一种工程措施在河道防洪治理得到应用.然而,在流域来沙大幅减少的背景下,对河道实施一定规模的疏浚以扩大行洪能力,不仅是可能的,而且不会发生严重回淤,疏浚效果可以长期...     

官厅水库流域水沙优化配置与综合治理措施研究Ⅱ--流域水沙优化配置与水库挖泥疏浚方案

通过现场调研、实体模型、数学模型和资料分析等手段，对官厅水库上游流域水土流失现状与治理效果、水沙配置与利用、水库挖泥疏浚治理措施与效果等问题进行了系统的研究。流域水沙配置的内容主要包括水土保持拦沙、水库拦沙、引水用沙和河道淤积等，在基本摸清了流域泥沙配置现状及其对官厅水库减淤效果的基础上，指出改善和提高流域引水用沙、滩地滞沙和水土保持拦沙等方面的泥沙配置能力是减轻官厅水库泥沙淤积的重要目标；论证了挖泥疏浚是解决官厅水库泥沙淤积(包括拦门沙淤堵和坝前淤积)的重要措施，小底宽挖泥槽疏浚方案(15m方案)可作为枯水年连通两库的应急供水工程措施，宽挖槽疏浚方案(宽300m或500m)和防淤堤方案为近期拦门沙整治方案，其中S型防淤堤方案具有局部导沙入妫的作用，挖泥疏浚可以有效地缓解坝前泥沙淤积严重所造成的危险局面；清淤应急供水工程方案实施后的连通渠回淤监测成果表明，连通渠回淤少，不存在淤堵问题，与实体模型试验成果一致，起到了连通永库和妫库的作用。     

基于CCHE模型的重力沉沙池水沙数值模拟

为了研究重力沉沙池流量、含沙量与水沙分离效率的关系,借助CCHE软件,建立CCHE2D水沙两相流数学模型,采用混合掺长紊流模型,对重力沉沙池进行数值模拟,得到沉沙池内水流流态、悬移质输移规律以及沉沙池的水沙分离效率,并在前人研究的基础上,进一步对不同流量、含沙量情况下,其流量和含沙量对沉沙池水沙分离效率的影响进行分析。结果表明:当流量在0. 05～0. 30 m~3/s时,随着流量增大,则流速增大,水流挟沙力增大,不利于泥沙沉降,使沉沙池的水沙分离效率降低;改变初始含沙量(5～20 kg/m~3),随着初始含沙量的增大,由于沉淀池尾部回流区存在,使得部分泥沙直接被带入清水池,使得沉沙池水沙分离效率降低。     

Monitoring of River Contamination Derived From Acid Mine Drainage Using Airborne Imaging Spectroscopy (HyMap Data,South‐West Spain)

Imaging spectroscopy is used in this work as an essential mapping tool to monitor changes in contaminated river sediments. Multidate hyperspectral image data (HyMap) are utilized to identify spatial mineral patterns, to detect temporal changes in mineralogy and to link these changes with geochemical processes and short‐term climate characteristics. River sediments contaminated by acid mine drainage are covered by crusts with variably hydrated iron sulphate. The mineralogy of the crusts and the grain size of the underlying fluvial sediments overlap. The spectra used to build up maps from HyMap data are diagnosed mineralogically with archive spectral libraries from pyrite oxidation minerals from well‐known sequences of minerals. The maps compiled from hyperspectral imagery display generalized oxidation shown by the coatings over river sediments following warm and dry periods with low water level. After the wet periods, the area covered by oxidized mineralogical phases recedes in favour of hydrated sulphate. The iteration of image processing algorithms and the mineralogical and potential contamination in a geological context are described. Change detection of the mineral crusts on the river sediments by mapping using hyperspectral remote sensing data may thus enable a quantitative and qualitative environmental evaluation by the regulators. Copyright © 2014 John Wiley & Sons, Ltd.     

Concentration and distribution patterns of naturally occurring radionuclides in sediments and flood plain soils of the catchment area of the river Elbe

The impact of uranium mining and milling as well as that of traditional mining activities on river sediments and flood plain soils in the catchment area of the river Elbe was investigated over the years 1994 to 1995. Contamination resulting from mining activities has been identified by comparing the median values for the measured radionuclides, and by establishing the ratio between Ra-226 and Ra-228. The transport and deposition of contaminated materials as a result of high water events, and river discharge of waste water from mining and milling facilities, can be considered to be the main paths of sediment and soil contamination. Sediments and flood plain soils located in the vicinity of former uranium mining and milling sites are primarily influenced by discharges of waste water. Long distance transport and deposition at dams, barrages and on flood plains has mainly been caused by high water events. In many cases the radionuclide concentrations were higher in the subsurface layer than in the top layer of flood plain soil. Due to termination of uranium mining and milling activities, no significant contamination of newer or fresh sediments was found. Radiation exposure arising in relation to angling or walking on flood plains is low.     

Modeling the Transport of Sediments and Hydrophobic Contaminants in the Lower Saginaw River

A study of processes that are significant in the transport and fate of sediments and hydrophobic contaminants in the lower Saginaw River over long periods of time, up to 25 years, has been made. The numerical model used in the analysis consists of a two-dimensional, vertically-integrated, time-dependent hydrodynamic and sediment transport model coupled (a) with a three-dimensional, time-dependent model of the dynamics of the sediment bed and its properties and (b) with a model of the transport and fate of hydrophobic contaminants. Calculations of sediment transport for different magnitude flow events demonstrate the variations in erosion and deposition at different sites and the dependence of this erosion and deposition on the flow rate. These calculations also illustrate the inherent variability, or uncertainty, in any long-term predictions since the results depend to a great extent on the times of occurrence of the largest flow events, times which can not be predicted but are only known statistically. The transport and fate of PCBs were also investigated with the emphasis on the effects of (a) large flow events, (b) incoming upstream PCB loads, and (c) burial of contaminated sediments by clean sediments with subsequent erosion of sediments by a large flow event. The analysis clearly shows that the major erosion of contaminated sediments occurs at the edge of the river channel with little erosion of contaminated sediments in the near-shore area.     

河北某电镀污染场地Cr6+污染调查

为查明河北某电镀污染场地Cr~(6+)的污染程度和空间分布,并对其可能影响的污染范围及风险进行预测,采用取样化验、三维数值模拟等方法对污染场地进行调查和评价。结果表明:污染场地在未进行人工干预治理时,污染物受到地下水流向和含水层介质的影响,在电镀废水停止泄露后的180 d内,调查区西南部大片区域的地下水有被污染的风险。