海河流域典型区域重金属沉积物生态风险研究

针对水库重金属污染及其生态效应问题，分析海河流域北部4座典型水库沉积物中6种重金属(As、Cr、Cu、Ni、Pb和Zn)的分布情况，并评价污染物类型的相关性。采用地累积指数法、潜在生态风险指数法和物种敏感性分布法分析4个水库沉积物中重金属的生态风险。结果表明：沙河水库、密云水库和于桥水库的重金属沉积物生态风险等级为优，官厅水库重金属沉积物生态风险等级为良。不同重金属对5%的底栖生物物种的危害质量分数(HC5)不同，由高到低依次为As(0.210 mg/kg)>Ni(0.071 mg/kg)>Cr(0.052 mg/kg)>Zn(0.050 mg/kg)>Cu(0.006 mg/kg)>Pb(0.005 mg/kg)。研究成果有助于了解水库沉积物中重金属的生态风险，为水库生态管理提供依据。     

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.     

Mineralogical and geochemical investigation of sediment in the Snake River arm of the Dillon Reservoir, Summit County, Colorado, USA

Mineralogical and chemical analyses of sediment in the Snake River arm of the Dillon Reservoir provided insight into the transport and fate of trace metals in this system, which provides potable water to the city of Denver in Colorado. The sediments contain metal hydroxide precipitates and sorbed trace metals that formed upstream in the Snake River and in Deer Creek, Peru Creek and other tributaries. Iron and trace metal concentrations in the sediments reach a maximum about halfway down the 3.3 km arm, with their distribution probably controlled by physical processes acting on the settling of precipitates entering the arm from the mouth of the Snake River. The concentration of molybdenum is at background concentration near the mouth of the Snake River, increasing towards the centre of the reservoir, where values are 10 times greater, owing to contamination from the Ten Mile Creek and Blue River arms of the reservoir. The results of a sediment‐leaching experiment demonstrated that the relative ease of extraction with a decreasing pH value in the sediments is zinc > cobalt > copper > nickel > lead. Although most of the trace metals are low in concentration, or are strongly sorbed in the sediments, the relatively high concentration of zinc and its relatively high mobility make it a metal of potential concern in the reservoir.     

青狮潭水库底泥重金属污染特征及潜在生态风险

广西桂林青狮潭水库由东湖和西湖两部分组成,为了研究青狮潭水库底泥重金属污染分布特征及潜在生态风险,测定了青狮潭水库不同位置底泥中5种重金属(As,Cd,Cr,Hg,Pb)的含量,并通过地累积指数法和潜在生态风险指数法评价了重金属的污染程度和潜在生态风险。结果表明:东湖底泥中As和Cd含量较西湖高,西湖Hg和Pb含量高于东湖;底泥中Cr主要来源于成土母质,船只通行是造成Pb污染的主要原因;东湖底泥中As和Cd可能主要来源于东江上游煤矿开采;西湖底泥中As,Cd,Hg与营养元素间存在显著相关性,其来源可能与周边农业活动和前期水库内网箱养鱼有关;根据地累积指数,重金属污染强度排序为Cd,As,Pb,Hg,Cr,Cd和As为主要污染元素;重金属潜在生态风险大小排序为Cd,Hg,As,Pb,Cr;东湖底泥重金属潜在生态风险强于西湖。     

长江上游岷江流域水沙变化特征分析

岷江流域来水来沙过程对三峡水利枢纽工程的正常运行具有较大的影响.通过资料分析,初步认为该流域水沙年际变化主要为:岷江干流段水量变幅不大,沙量在彭山以上地区、彭山-五通桥及以下区域呈减少趋势;而其支流青衣江上游、大渡河上游水量有所减少,但沙量有所增加,来沙量占流域沙量的65%左右,但随着青衣江和大渡河的逐步开发,水利水电工程拦沙作用将逐渐增大,以致岷江彭山-五通桥区间段来沙量将来会有所减少.根据岷江流域主要测站资料分析,并结合流域内水库(水电站)建设情况,除降雨变化可能引起个别年份输沙量有所增加外,岷江高场站水沙关系1991年前无明显变化,但近期水沙关系发生明显变化,较其它年代同水量下沙量相对减小,其减沙原因主要是流域降雨条件变化及水库拦沙作用.     

Prediction of sediment inflows to Angereb dam reservoir using the SRH‐1D sediment transport model

Angereb Dam, located in Ethiopia, was constructed in early 1994 as a water supply for the town of Gondar up to the year 2020. The reservoir could not achieve this objective, however, because of significant sedimentation problems. Accordingly, one objective of this study was to simulate the historical reservoir sedimentation pattern, as well as predict the near future (until 2015) sedimentation pattern of Angereb Reservoir. The Sedimentation and River Hydraulics one‐dimensional model (SRH‐1D), version 2.6, was used for this purpose. Another objective was to propose possible mitigation measures to reduce the quantity and rate of sedimentation in the reservoir. There was generally good agreement between measurements and model simulations, with the observed trends being well simulated. The exception was that the model tended to overpredict the sediment deposition volumes in the upstream reaches of the reservoir. The two mitigation alternatives for addressing the sedimentation problem, namely managing sediments in the watershed and flushing sediment through the dam bottom outlet, appear to be technically feasibility, with a predicted reduction of the volume of deposited sediment between 63 and 80% be achievable.     

黑臭水体底泥调查分析及达标清淤量研究

底泥污染是造成茅洲河流域水质黑臭的关键因素之一。本文通过对底泥勘查取样检测,采用底泥沉积物单因子污染指数法对底泥营养盐污染进行分析评价,结果显示,营养盐、有机质污染均达到了重度污染等级。采用单一重金属潜在生态风险系数和多金属潜在生态风险系数法对重金属污染程度进行分析评价,结果显示,重金属污染达到了极强生态风险等级。根据底泥污染程度的不同,结合垂向变化分析,确定了不同区域底泥达标清淤深度在0.7~2.5m之间,继而确定了清淤量为331万m³,为茅洲河流域污染底泥清淤提供了可靠依据。其研究路线、方法可为类似工程参考。     

Temporal and spatial patterns based on sediment and sediment–water interface characteristics along a cascade of reservoirs (Paranapanema River, south-east Brazil)

Physical and chemical characteristics of the sediments in a cascade of eight reservoirs located in the Paranapanema River (south‐east Brazil) were analysed during two consecutive years during summer (January), autumn (April), winter (July) and spring (October) of 2000 and 2001, respectively. The granulometric texture, organic matter content and nutrient concentration (total nitrogen and phosphorus) were determined in the superficial sediment of 19 sampling stations, as well as the temperature, dissolved oxygen, pH, conductivity and redox potential in the bottom layer of the water column. Seasonal and spatial changes were observed for both years, especially for organic matter and nutrient concentrations. Three different areas could be identified along the river, which corresponded to the upper, middle and lower Paranapanema basin. The first area was characterized by an increase of nutrients and organic matter in the sediments and a decrease of temperature and dissolved oxygen in the downstream direction. The second one represented a region where fluctuations in nutrient and organic matter concentrations and a reduction in dissolved oxygen were observed. In the third area, there was an increase in nutrient and organic matter in the sediments and also an increase in temperature and dissolved oxygen towards the river mouth. The results of the principal components analysis, using water and sediments variables, showed the ordination of sampling stations by periods: wet (January–April) and dry (July–October) during 2000. This pattern was also verified during 2001, but with slight changes, probably due to the increase in the rains which would have produced certain homogenization effects along the river.     

Assessment of sediment quality of a tropical lake using sediment quality standards

Sediments are often reservoirs of contaminants in aquatic waterbodies, and their quality can be an indicator of the health of their ecosystems. Heavy metal pollution in sediments is highly significant because of their persistent and bioaccumulative nature. In this regard, sediment quality guidelines (SQG) are useful for categorizing sediment quality with respect to the contaminant level in them. An attempt was made in this study to assess the sediment quality of the Akkulam‐Veli (AV) Lake system on the basis of guidelines that incorporate assessment scales that differ in their approaches. Some link threshold levels of heavy metal concentrations on the basis of their likelihood to cause adverse effects, while others classify the sediment concentration ranges that correspond to the degrees of toxicity caused by them. The sediment quality of the study area was assessed by combining the available guidelines to formulate two new approaches in this study. Based on this approach, AV Lake is highly polluted with respect to chromium (Cr), nickel (Ni) and lead (Pb), while arsenic (As) and cadmium (Cd) are non‐polluting with a negligible potential for adverse effects.     

The assessment of suspended sediment inputs to Volta Lake

Information on a river basin's sediment yield is an important requirement for water resources development and management. In the Volta River basin of Ghana, data on suspended sediment yield are limited due to the lack of logistic support for systematic sediment sampling activities. This paper presents the results of a study using the available measurements of suspended sediment transport for eight monitoring stations in order to develop a simple predictive tool for estimating the suspended sediment yields for catchments for which no sediment measurements had been undertaken. Regression analysis was used to establish a relationship between specific suspended sediment yield and both the mean annual run‐off and the drainage basin area. The prediction model was used to estimate the sediment loads of the Volta River and its main tributaries (Black Volta, White Volta and Oti Rivers) in order to estimate the total suspended sediment input to the reservoir and the equivalent specific suspended sediment yield from the catchment surface. Although these sediment yield values are relatively low by world standards, the results obtained provide a basis for assessing future sedimentation problems in Lake Volta and for underpinning the development of sediment control and management strategies for the reservoir.     

Acute impacts of reservoir sediment flushing on fishes in the Yellow River

Dam sediment flushing can reduce reservoir sedimentation and deliver sediments to the downstream rivers. However, deceased fishes are often found in the Yellow River during the period of reservoir sediment flushing. To study the acute impacts of flushing and quantify threshold conditions for fish protection, field surveys and laboratory experiments were carried out during periods of sediment flushing. Field surveys in 2010 showed that dissolved oxygen (DO) decreased rapidly with the increase in suspended sediment concentration (SSC) and that deceased fishes involved 10 species. With the model of the severity of ill effects, the sediment flushing in 2010 was estimated to cause fish mortality of 0–20%. To study the lethal effect on fishes under controlled SSC conditions, laboratory experiments were performed with carp (Cyprinus carpio) exposed in water containing different SSCs. It is concluded that the high sediment concentration (average value of 90788 mg/l), fine particles (grain size < 0.075 mm), a long flushing duration (>2 days), and DO reduction (<2 mg/l) contribute to the deaths of fishes during the flushing period in 2010. To decrease lethal effects, the upper limits of SSC and duration are recommended as the peak SSC value of 55 000 mg/l and average value of 32 000 mg/l for the entire flushing period for flushing operations. The measures of SSC control and refuge construction are suggested for eco-friendly management.     

The seasonal and spatial variations of labile copper, iron, manganese, lead and zinc sediment fractions in Lake Naivasha, Kenya

Lake Naivasha is a freshwater lake with no surface outlet, lying within a closed basin of the Kenyan Rift Valley. It is perceived to be a lake undergoing anthropogenic stresses. This study is intended to determine the speciation of some selected heavy metals in the sediments of Lake Naivasha, as an indicator of potential pollution of the lake. Sediment and water sampling of the lake was conducted in March and May 2003, during the dry and wet seasons, respectively. Analyses of the speciation of heavy metals in sediment samples (<63 µm faction) were performed on sediment samples collected from five sites within the lake. The study results obtained indicated that influent Malewa River was not a source of labile copper (Cu), lead (Pb) or zinc, despite the river having the highest percentage clay content during the wet season (86%). Copper was highly distributed in the residual sediment fraction (average of 90%). Among the labile sediment factions, the highest quantity of Cu was in the oxidizable phase (3.58 and 2.30 µg g⁻¹ during the dry and wet season, respectively). Carbonate‐bound Cu was sparingly distributed during both the dry and the wet seasons, ranging between 0.74 and 1.81 µg g⁻¹. Iron was highly distributed in the oxidizable sediment phase, exhibiting concentrations ranging between 2.0 and 6.0 (×10³) µg g⁻¹. Relative to the other heavy metals, manganese was distributed in lower proportions in the residual sediment fraction. High concentrations of Pb were observed in the oxidizable phase from most of the sampling sites along the lake shore. Zinc was distributed largely in the oxidizable phase, being highest at sampling site SS, which was located near a municipal sewage input to the lake. The sediments collected at the sampling sites located in the deep portion of the lake exhibited the highest concentrations of labile heavy metals.     

泥沙粒径对重金属污染物吸附影响的研究

本文系统研究了不同粒径泥沙颗粒对重金属污染物的吸附作用，粗细不同的泥沙对重金属污染物的吸附能力差异很大，因此研究天然河流泥沙吸附能力必须考虑泥沙组成的非均匀性和各级泥少的含量，度量泥少量粒吸附能力的标准主要是吸附活性组分的含量，而不仅是粒径大小。     

近40年来长江口沉积物粒度变化及其对底床冲淤的响应

在全球变化和人类活动的双重驱动下,长江口的沉积物来源、输运和河床冲淤正在经历持续性调整。为了探索近40年长江口沉积物输运和海底冲淤时空变化趋势,基于1980—2020年长江口海底沉积物粒度和水下地形数据,采用沉积物粒径趋势模型和多种空间分辨率网格统计分析方法开展研究。结果表明,长江口北支沉积物总体向河道中下部汇聚,南支则在南、北港分流处靠近崇明岛区域形成沉积中心,该结果与基于2012—2020年地形计算的冲淤变化基本相符,沉积中心具有较大的淤积幅度。多年统计结果表明:1980—2003年为高强度输沙时期,整个河口区处于淤积状态,沉积物粒径变细但整体变幅较小;2003—2012年河流输沙量快速降低背景下,2009年前河口区整体依然处于淤积状态,粒径变化不显著;2009—2012年是由淤积转为冲刷的过渡期,口外区域首先出现了小范围侵蚀和沉积物粗化现象;2012—2020年,河口区整体出现大面积侵蚀和粒径粗化现象,粒径与侵蚀变化间呈显著相关。研究发现,高分辨统计网格可以更有效地捕捉到小范围地貌由淤转冲的信号。总体而言,近40年来,长江口已经由显著淤积转为局部侵蚀,未来可能面临持续性的海岸侵蚀灾害。     

Nutrient concentrations in the surface sediments of Lake Chivero,Zimbabwe: A shallow,hypereutrophic, subtropical artificial lake

A lake‐wide survey in Lake Chivero, Zimbabwe, was performed to (i) examine the spatial distribution of three sediment grain sizes; (ii) determine their nutrient concentrations; and (iii) analyse the relationships between the measured surface sediment variables in the three sediment grain sizes. The results of this study indicated sand, silt and mud sediments occupied about 24, 22 and 54%, respectively, of the lake area. All the measured physicochemical variables varied significantly among the three sediment grain sizes (P < 0.05, anova ). High values for pH, dissolved oxygen and NO₃ were observed in the sand sediments, while water depth, electrical conductivity, soluble reactive phosphorus, NH₄, total phosphorus, total nitrogen and total organic carbon were observed in the mud sediments. In the silt sediments, most measured variables showed intermediate values. Intervariable correlation indicated varied correlation patterns among the three sediment grain sizes. Information generated in this study is essential for an accurate delineation of the spatial extent of nutrient and contaminant distribution in the sediment of Lake Chivero and will facilitate the ability of lake managers to derive a comprehensive nutrient budget of the lake as a means of establishing realistic target conditions for lake restoration.     

Stream corridor and upland sources of fluvial sediment and phosphorus from a mixed urban-agricultural tributary to the Great Lakes

Like many impaired Great Lakes tributaries, Apple Creek, Wisconsin (119 km²) has Total Maximum Daily Load (TMDL) targets for reducing suspended sediment and total phosphorus by 51.2 % and 64.2 %, respectively. From August 2017 - October 2018, a stream sediment budget and fingerprinting integrated study was conducted to quantify upland and stream corridor sources of suspended sediment and sediment-bound phosphorus. Phosphorus concentrations varied among source groups and fluvial sediments, with higher concentrations among suspended sediment and cropland soils. Eroding streambanks identified in the stream corridor sediment budget accounted for 100 % of the TMDL Soil and Water Assessment Tool (SWAT) suspended sediment load but only 20 % of the total phosphorus load. Fine-grained streambed sediment equated to approximately-three years of modeled suspended sediment load but only one third of total phosphorus load. The two primary sources of fine-grained streambed sediment were streambanks and cropland, with relative streambank contributions increasing with downstream direction and watershed area. The relative proportion of suspended sediment varied by season and streamflow; however, cropland and streambank erosion accounted for 54 % and 23 % of the suspended sediment when weighted by of the proportion for representative streamflow. Urban land was a source in the upper watershed, but the signature was sequestered by a mid-watershed detention basin. Contributions from construction sites were higher in the fall 2018, likely corresponding to increased activity following a wet spring. These integrated techniques helped describe sources, transport, and sinks of fluvial sediment and phosphorus throughout the watershed at a range of spatial and temporal scales.     

黄土高原北洛河沉积物生态风险解析

以黄土高原的典型工业污染河流北洛河为研究对象,测定其干支流17个采样点沉积物中的8种重金属(Hg、As、Cd、Cr、Cu、Pb、Ni、Zn)质量分数,结合描述性统计结果对重金属的空间分布特征进行分析。进一步利用地累积指数法、内梅罗综合污染指数法和潜在生态风险指数法分析重金属的污染程度与生态风险,利用PMF模型和相关性分析进行来源解析。结果表明：北洛河上游沉积物中重金属的平均质量分数高于中下游,As、Cd和Zn的均值分别为背景值的1.26、1.28和1.41倍,Zn、Hg、Cd、Pb、As和Cu的变异系数大于30%,为高度变异水平。地累积指数法与内梅罗综合污染指数法显示,北洛河上游B₁处和下游B₁₃处沉积物中重金属污染处于中高水平;潜在生态风险指数法显示,单一元素污染危害程度依次为Cd>Hg>As>Cu>Ni>Pb>Zn>Cr,整体来看,Cd和Hg的潜在生态危害较大,中游B₁₀和下游B₁₃存在中等生态风险,其余点位均为轻微生态风险。来源解析表明,北洛河沉积物中...     

Sedimentology and Geochemistry of Modern Sediments in the Kingston Basin of Lake Ontario

Accumulation of Recent fine sediment is limited to deep water areas in the Kingston basin and thicknesses of more than 50 cm are found only in the St. Lawrence trough; elsewhere, sands and silty sands are largely composed of reworked material. Local sources provide little input of fine sediment to the Kingston basin. Statistical relationships derived from geochemical analyses indicate several forms of association between heavy metals and organic carbon, sulphides, clays, hydrous Fe and Mn oxides, and carbonates. A comparison between Kingston and Niagara sediments shows that the combined effects of riverine and lacustrine erosion have resulted in a generally greater content of carbonates in the Niagara sediments. The content of Fe (which is partly influenced by redox potential) is highest, however, in sediment of the Kingston basin, where higher P values are also associated with an increased clay content. Differences in the concentrations of heavy metals in Lake Ontario, except for Hg, Co, Cu, and Zn, are largely explained by variations in silt and clay contents. Contaminant loadings from the Niagara River are largely responsible for the anomalously high concentrations of Hg and, to a lesser extent, Cu and Zn. Cobalt occurs at higher concentrations in the sediments of eastern Lake Ontario, where its presence is thought to reflect glacial dispersal patterns.     

Assessment of heavy metal contamination in coastal lake sediments associated with urbanization: Southern Kerala,India

The study of the spatiotemporal variation of heavy metals in lake sediments is of great importance because heavy metals can result in toxic effects on aquatic biota through bioaccumulation. This study was undertaken to evaluate the degree of heavy metal contamination in the lacustrine sediments and the corresponding environmental deterioration in a tropical, urban, coastal lake (Akkulam–Veli), located in Kerala, India. The spatiotemporal variations of the cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni) and zinc (Zn) concentrations in the lake sediments, as well as various indices of anthropogenic contamination, including Contamination Factor (CF), Pollution Load Index and Geoaccumulation Index (Igeo), were used to assess the degree of contamination. This study indicated contamination of the lake sediments with Cu, Pb and Zn. Urban domestic sewage and land run‐off are the major drivers of the heavy metal loads to the lake. During the pre‐monsoon, sediment contamination occurs in the upstream portion of Akkulam Lake because of a high clay content in the sediments. During the monsoon period, Akkulam Lake and the upstream portion of Veli Lake exhibit sediment contamination owing to high silt content. Domestic sewage is the main source of copper and zinc to the lake. Sewage bypass into the drains in the lake basin is largely responsible for the copper and zinc sediment contamination. High traffic levels and wastewater discharges from service stations/workshops are the main cause of the Pb loads entering the lake. Rubber particles of vehicle tires contain zinc and copper pigments that can accumulate on the surface of busy streets, entering the drains during rainfall events. Based on these study results, the accumulation of copper, zinc and lead in lake sediment can be controlled to a great extent by restricting the above‐noted activities. As the sediment content of lead, zinc and copper is confined to the clay fraction during the non‐rainy season and to the silt fraction during other seasons, lake restoration work should largely incorporate treating the clay and silt fractions, respectively, during both the non‐rainy season and rainy season.     

Assessment of element distribution and heavy metal contamination in Chilika Lake sediments (India)

Chilika Lake is situated on the Indian east coast. It is one of the largest lagoons in the world, with a unique assemblage of marine, brackish water and freshwater species. Due to the opening of new connections to the sea in the years 2000 and 2008, an environmental change is expected in the lagoon. The study gives an assessment of sediment contamination by heavy metals on the verge of this change (sampling campaign in 2000). Sediment samples from two surface levels (0–5 and 30–35 cm), and from depth profiles, were analysed for mineralogical composition, main and trace element concentrations, and element bonding forms. Background concentrations from a depth profile were also examined. The profile spans a time of ≈13 500 years. Age determinations by radiocarbon dating and the ¹³⁷Cs- and ²¹⁰Pb-method were carried out. The composition of the surface sediments is generally uniform. The heavy metals exhibit slightly decreasing concentrations from NE to SW, thus indicating the supply of contaminants from the Mahanadi River. The anthropogenic portion of the heavy metal supply is mainly bound to Fe-oxide-hydroxides. Phosphorus is enriched in the sediments of the southern lake sector. Changes in element concentrations in the last 13 500 years have occurred mainly in two steps. The long-term variations exceed the anthropogenic changes caused by the Mahanadi River inputs. The very sensitive response of coastal area fabrics on climate changes also causes fast geogenic changes in element concentrations in sediments (similar grain sizes). This prevents the use of element concentrations from deep sediment horizons to define contaminations in those areas.