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551.
J. Roger McHenry Jerry C. Ritchie Charles M. Cooper 《Journal of the American Water Resources Association》1980,16(6):1049-1056
ABSTRACT: Sedimentation rates since 1954 in Lake Pepin, as determined from the content of fallout cesium-137 in the sediment profile, have exceeded 2.5 cm/yr in the upper part of the lake. These rates, although somewhat less than those of the previous half century (1895–1954), are sufficiently large that the upstream portion of Lake Pepin is threatened with conversion to a marsh within a century. The density of the sediments measured increased with depth in the sampled profile from 1.1 to 1.2 g/ml at the sediment surface to 1.4 to 1.5 g/ml at 2- or 3-m depth. There was little or no change in the patterns of textural composition or density of the sediment profile with depth and age over the past 80 to 150 years. 相似文献
552.
Charles J. Boyter Martin P. Wanielista 《Journal of the American Water Resources Association》1973,9(3):499-511
ABSTRACT Relevant information on the restoration of lakes is presented. The restoration procedures considered are applicable to the water, the bottom sediments, and aquatic plant improvement. A summary of thirteen (13) suggested methods of restoration are reviewed. 相似文献
553.
Contaminated sediments are receiving increasing recognition around the world, leading to the development of various sediment quality indicators for assessment, management, remediation, and restoration efforts. Sediment chemistry represents an important indicator of ecosystem health, with the concentrations of contaminants of potential concern (COPCs) providing measurable characteristics for this indicator. The St. Louis River Area of Concern (AOC), located in the western arm of Lake Superior, provides a case study for how numerical sediment quality targets (SQTs) for the protection of sediment-dwelling organisms can be used to support the interpretation of sediment chemistry data. Two types of SQTs have been established for 33 COPCs in the St. Louis River AOC. The Level I SQTs define the concentrations of contaminants below which sediment toxicity is unlikely to occur, whereas the Level II SQTs represent the concentrations that, if exceeded, are likely to be associated with sediment toxicity. The numerical SQTs provide useful tools for making sediment management decisions, especially when considered as part of a weight-of-evidence approach that includes other sediment quality indicators, such as sediment contaminant chemistry and geochemical characteristics, sediment toxicity, and benthic macroinvertebrate community structure. The recommended applications of using the numerical SQTs in the St. Louis River AOC include: designing monitoring programs, interpreting sediment chemistry data, conducting ecological risk assessments, and developing site-specific sediment quality remediation targets for small, simple sites where adverse biological effects are likely. Other jurisdictions may benefit from using these recommended applications in their own sediment quality programs. 相似文献
554.
Griebler Christian Sonntag Bettina Mindl Birgit Posch Thomas Klammer Susanne Psenner Roland 《Water, Air, & Soil Pollution: Focus》2002,2(4):33-62
Since nearly one hundred years Traunsee experiences the import of tons of liquid and solid waste originating from salt and soda production. Today, the lake exhibits chloride concentrations of up to 170 mg L-1 and 19% of the lake floor are directly or indirectly influenced by industrial deposits (ID). Based on the comparison of several microbial parameters in unaffected, directly affected and intermediate lake bottom sediments, the ecological integrity of the lake was evaluated. The highly alkaline ID, which were exclusively colonized by microorganisms, harbored a bacterial community reduced by a factor of 10 in abundance and biomass compared to undisturbed sediment areas within the lake. The bacterial community of ID was furthermore characterized by a reduced content of actively respiring cells (INT-formazan reduction), a lower frequency of dividing cells (FDC) and a significantly reduced cell and biomass production. A 80 to 90% reduction in carbon recycling is estimated for the area exclusively covered by ID. Protists, although occasionally absent from the industrial sediments, were in general found to be less sensitive to the contaminant stress. Differences in alkalinity and dissolved organic carbon (DOC) concentrations of sediment porewaters as well as the total organic content and C/N ratios of sediments partly explain the microbial pattern observed at the various sampling sites. Possible consequences of the continuous industrial tailings for the whole lake ecosystem and the validation of the ecological integrity are discussed. 相似文献
555.
Marcel van der Perk Philip N. Owens Lynda K. Deeks Barry G. Rawlins 《Water, Air, & Soil Pollution: Focus》2006,6(5-6):443-451
A spatially extensive geochemical data set of stream water and bed sediment composition across the Tamar catchment in south-west
England was analysed to identify the key bed sediment properties that control the in-stream dissolved reactive phosphorus
(DRP) concentrations during baseflow conditions. Linear regression analysis of the streamwater DRP concentrations and the
distribution coefficient K
d for DRP revealed that the former is positively correlated with total SiO2 and Al2O3, and negatively correlated with K2O. The primary control on these major element distributions is the dominant bedrock geology. The data suggest that streamwater
DRP concentrations are mainly controlled by adsorption to clay minerals. Where P concentrations in streamwater were considerably
elevated by inputs from point sources, DRP concentrations are also controlled by precipitation of hydroxyapatite. 相似文献
556.
The distribution of some heavy metals, namely Cd, Pb, Zn, Fe, Cu, Cr and Mn in epipellic sediments of Igbede, Ojo and Ojora
rivers of Lagos was studied weekly in the early summer (November) of 2003. The levels of selected trace metals were determined
using Atomic Absorption Spectrophotometer (UNICAM 969 AAS SOLAR). Trends in heavy metal burdens in the sediments revealed
weekly variations in all the rivers assessed. Statistical analyses also showed different mean levels of trace metals in the
aquatic environments, the distribution of which followed the sequence Fe > Zn > Mn > Pb > Cu > Cr > Cd, Fe > Zn > Cu > Mn
> Pb > Cr > Cd and Fe > Zn > Mn > Cu > Cr > Pb > Cd in Igbede, Ojo and Ojora rivers respectively. Fe recorded the highest
concentration levels (1,582.95 ± 96.57 μ g/g–1,910.34 ± 723.19 μ g/g) in all the sediments investigated while the Cd levels
(0.06 ± 0.10 μ g/g–0.47 ± 0.36 μ g/g) were the lowest. Expectedly, trace metal concentrations in fine grain muddy sediments
of the Igbede and Ojo coastline were much higher than those of Ojora which consist of coarse and sandy deposits covering the
near shore area. Generally, the results obtained fell within tolerable limits stipulated by World Health Organization (WHO). 相似文献
557.
沉积物内源与外源重金属形态与酶活性的相关性 总被引:1,自引:1,他引:0
文章以表层沉积物为研究对象,采用改进的Tessier连续萃取法,研究了表层沉积物中重金属(内源体系:Fe、Mn、Cu、Zn和Pb;外源体系:掺杂Cu、Zn和Pb后的Fe、Mn、Cu、Zn和Pb)形态和酶(蛋白酶、脱氢酶、磷酸酶、蔗糖酶)活性在一定时间(45d)内的转化趋势,探讨了沉积物中重金属形态与酶活性的相关性。结果表明,在外源体系中,Cu、Zn和Pb的掺杂对Fe和Mn的形态转化影响较小,而Cu、Zn和Pb显著地由残渣态向相对不稳定形态转化,转化幅度均大于20%。外源重金属掺杂初期(前5d),重金属对沉积物中的酶有一定的活化作用,但经过一段时间后以抑制作用为主。相关性分析表明,当掺杂外源重金属后,沉积物中酶的活性与重金属形态的相关性减弱,与内源体系中重金属和酶的活性关系存在明显差异。 相似文献
558.
滦河流域多环芳烃的污染特征、风险评价与来源辨析 总被引:14,自引:2,他引:12
在滦河上、中、下游和河口地区布设了15个采样点,对滦河流域的河水和表层沉积物中多环芳烃(PAHs)进行了分析.结果表明,水中PAHs总量为9.8~310ng.L-1,表层沉积物中PAHs总量最高达478ng.g-1.城市地区河段中PAHs的浓度高于农村河段中PAHs的浓度,河口地区相对中游地区污染较轻.就组成特征而言,水中PAHs以3环(40.9%)、4环(56.2%)为主,表层沉积物中PAHs以3环(30.0%)、4环(39.3%)、5环(15.8%)为主.总的来讲,3环、4环PAHs是滦河流域PAHs最主要的成分.地表水健康风险评价结果显示,韩家营、瀑河口两个采样点苯并[a]芘(BaP)毒性当量值(EBaP)分别为11.8、11.4ng.L-1,超出中国国家环境保护部(CEPA)制定的EBaP=2.8ng.L-1的国家标准,存在不利的健康风险.表层沉积物生态风险评价结果显示,韩家营、上板城、乌龙矶地区的PAHs可能存在着对生物的潜在危害,剩余研究区域不存在生态风险.滦河水和表层沉积物PAHs主要表现为以草、木柴和煤燃烧来源为主的特征,部分样点存在燃油与木柴、煤燃烧的混合来源特征.瀑河口、大黑汀受石油源污染影响明显. 相似文献
559.
560.