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1.
P. Paiva J.-M. Jouanneau F. Araújo O. Weber A. Rodrigues J.M.A. Dias 《Water, air, and soil pollution》1997,99(1-4):507-514
The Tagus estuary, located at the western Iberian coast in front of Lisbon is the largest one in Portugal, where it drains highly populated and industrialised regions. The amount of sediment transported by this river is so great that the submarine delta is one of the largest in the Iberian margin, very well defined and reaching the 70m isobath. The geochemical pattern of the muddy deposit off the Tagus river has been determined by elemental analyses of bulk surficial sediments, collected at the Portuguese margin adjacent to the Tagus estuary. Measurements were carried out by energy-dispersive X-ray fluorescence spectrometry (EDXRF). Sediments were usually composed of fine particles (silts and clays) and were high in organic matter (measured as loss on ignition). Elemental concentrations for Zn and Ph clearly indicate an estuarine contamination probably associated with discharges from urban centers or due to the influence of the industries located downstream. apparently the depletion on the Cu contents is caused by its release (soluble complexes) into the marine environment. Variations observed in the elemental distribution of the sediments of the Tagus with distance from the estuary seem to be dependent on the grain size distribution related to the dynamics of the sediment transport. 相似文献
2.
Fluvio-coastal interactions are examined on a progradational sand, and mixed sand and gravel beach sequence between the Ashley and Kowai rivers, Pegasus Bay, New Zealand. This coastal system presents an example of a wave-dominated environment energetic enough to deal with the sediment supply derived from the rivers, but where the coast is still prograding. Progradation occurs because of the inability of the marine system to evacuate wave-eroded sediment from the bay floor. This results in gradual nearshore aggradation until nearshore storage is filled and sediment is finally transported landward to form a new beach ridge. This type of coastal system can be identified by a diagnostic morphological assemblage comprising a ‘small river’ coastal morphology (sensu Zenkovich (1967, Processes of Coastal Development, Oliver and Boyd, Edinburgh) backed by a sequence of beach ridges. Sediment fractionation (shape and size sorting) is identified as the primary effect of erosional processes on a mixed sand and gravel beach. Fractionation is capable of converting sandy beaches with minor gravel components to graveldominated beaches. Gravel is concentrated by the evacuation of sand from the shoreface. This occurs dominantly through storm sifting but also occurs in response to normal swash processes. This process is very similar to the process of chenier production on mixed mud and sand beaches, and fractionation is highlighted as a dominant erosional process on mixed beaches, irrespective of grain size. 相似文献
3.
Wim Salomons 《Journal of Soils and Sediments》2005,5(1):2-8
- Dedicated to Prof. Dr. Ulrich Förstner on his 65th birthdayBackground Sediments pose problems at their deposition sites when there is too little sediment (e.g. wetlands) or too much sediment (e.g. navigable waterways) and, additionally, when they are contaminated. These problems often have their origin upstream in the river catchment. Objective Global aspects of changes concerning sediment quantity and quality, as they affect downstream areas, are reviewed. A case study of estuarine sediments demonstrates how a holistic approach helps in understanding and predicting their present and future quality. Results and Conclusions Globally, large reservoirs intercept between 25 and 30% of the sediment and consequently supply the coast with impacts on wetlands and coastal morphology. In estuaries, the composition of sediments is determined by the mixing of marine sediments supplied from the coast and the supply by rivers. Natural tracers can be used to predict mixing ratios of marine to fluvial sediments in estuaries, and hence their contamination. Scenarios on implementation of pollution abatement, the implementation of regulations as well as climate change are needed to predict future sediment quality in downstream areas. The results show, even for a ‘green’ scenario, that sediment quality in the Rhine catchment will pose future problems due to the temporal storage of contaminants in soils and sediments.Recommendations and Outlook The current methods applied make use of existing models linking sediment transport with point and diffuse sources in the river catchments and scenarios on the development of strength of point and diffuse sources. However, more effort is needed to come to a uniform framework which includes land use changes and links with more advanced scenario methodology for long to medium-term management of sediment quality and quantity in river catchments. 相似文献
4.
Rute Cesário Holger Hintelmann Nelson J. O’Driscoll Carlos E. Monteiro Miguel Caetano Marta Nogueira Ana M. Mota João Canário 《Water, air, and soil pollution》2017,228(7):257
Mercury (Hg) dynamics was evaluated in contaminated sediments and overlying waters from Tagus estuary, in two sites with different Hg anthropogenic sources: Cala Norte (CNOR) and Barreiro (BRR). Environmental factors affecting methylmercury (MMHg) production and Hg and MMHg fluxes across sediment/water interface were reported. [THg] and [MMHg] in solids (0.31–125 μg g?1 and 0.76–201 ng g?1, respectively) showed high variability with higher values in BRR. Porewater [MMHg] (0.1–63 ng L?1, 0.5–86% of THg) varied local and seasonally; higher contents were observed in the summer campaign, thus increasing sediment toxicity affecting the sediment/water Hg (and MMHg) fluxes. In CNOR and BRR sediments, Hg availability and organic carbon were the main factors controlling MMHg production. Noteworthy, an upward MMHg diffusive flux was observed in winter that was inverted in summer. Although MMHg production increases in warmer month, the MMHg concentrations in overlying water increase in a higher proportion compared to the levels in porewaters. This opposite trend could be explained by different extension of MMHg demethylation in the water column. The high concentrations of Hg and MMHg and their dynamics in sediments are of major concern since they can cause an exportation of Hg from the contaminated areas up to ca. 14,600 mg year?1 and an MMHg deposition of up to ca. 6000 mg year?1. The results suggest that sediments from contaminated areas of Tagus estuary should be considered as a primary source of Hg for the water column and a sink of MMHg to the sedimentary column. 相似文献
5.
Ana Luisa Costa Susana M. Paixão Isabel Caçador Manuela Carolino 《Journal of Soils and Sediments》2007,7(6):418-425
Objective Microbial communities are a central component of trophic dynamics and biogeochemical processes on coastal systems, since most
of the processes in sediments are mediated by microorganisms and carried out by enzymes. Microorganisms play a key role in
decomposition processes in salt marsh sediments, although the significance of microbial dynamics is largely unexplored. A
culture-dependent (Ecoplate) and a culture-independent (extracellular enzyme activity [EEA]) approaches were evaluated in
their ability to distinguish the catabolic potential among sediments from Tagus estuary salt marshes with different proximities
to anthropogenic sources.
Methods Ecoplate was used to analyse the salt marsh community-level physiological profiles (CLPPs). Results were expressed as the
net area under the curve for each of the 31 response wells over a 3-day incubation period in two sediment horizons. The catabolic
profiles for salt marsh samples were analysed by Principal Component Analysis (PCA) and hierarchic clustering methods. EEA
was analysed by fluorescein diacetate (FDA) hydrolysis in two sediment horizons. The FDA is catalysed by extracellular enzymes,
i.e. esterases, lipases and partially by proteases. Results were expressed as μg g−1d wt h−1.
Results and Discussion In this study the CLPP and EEA data were not generally correlated. In Corroios salt marsh only in surface sediments higher
net areas corresponded to higher extracellular enzymatic activity, and in Alcochete deep sediments lower net areas corresponded
to lower enzymatic activity. Although EEA profiles more directly reflect the inherent activity of resident community in each
salt marsh sample, the CLPP profiles provide better assessments of diversity.
ESS-Submission Editor: Prof. Dr. Peter Schroeder, Institute of Soil Ecology, Department of Rhizosphere Biology, GSF — National Research Center for
Environment & Health, Ingolstaedter Landstrasse 1, 85758 Neuherberg, Germany (peter.schroeder@gsf.de) 相似文献
6.
《Land Degradation \u0026amp; Development》2017,28(8):2354-2369
The identification of sediment sources is important for catchment management, but few studies have been performed in Mediterranean areas. This study uses a multiproxy sediment fingerprinting approach to explore sources and dynamics of fluvial sediments in a rapidly urbanizing Portuguese peri‐urban catchment. X‐ray fluorescence was used to characterize the elemental geochemistry of sediments collected within the stream network after three storm events in 2012 and 2015. A range of statistical techniques, including hierarchical cluster analysis, was used to identify discriminant sediment properties and similarities between fine bed sediment samples of tributaries and downstream sites. Quantification of sediment supply from upstream sub‐catchments was undertaken using established sediment fingerprinting approaches. The geochemistry of the sediments was found to be influenced by both lithology and land‐use changes. In 2012, the sandstone sub‐catchment provided 75% of the <63 μm and 94% of the 63–125 and 125–2000 μm sediment, mostly from an Enterprise Park site undergoing deforestation and construction (covering 5% of the catchment area), with most of the remaining sediment deriving from the construction of a major road (1% of the catchment) in the limestone sub‐catchment. In 2015, planned and accidental retention basins below the Enterprise Park and major road sites, respectively, prevented some sediment from reaching the stream network, thereby reducing their importance as sediment sources. Sediment mobilization in urban areas with paved roads was small in comparison, but characterized by high heavy metal concentrations. The sediment fingerprinting approach adopted shows promise in identification of the main sources of sediments, necessary to underpin improved peri‐urban management strategies. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
7.
Background, Aim and Scope Past and present management of the Ebro catchment have altered water, sediment and nutrient fluxes of the lower Ebro River
and its delta. The construction of the Mequinensa and Riba-Roja dams during the 1960s disrupted the sediment transport continuity.
As a result, the lower Ebro River and its delta are facing a reduction in sediment delivery which is estimated to be up to
99% of its original yield (about 3 × 107 t/yr). Consequently, about 45% of the emerged delta will be under the mean sea level by 2100 due to subsidence and sea level
rise, whereas the delta coast is retreating at a rate of several meters per year in the mouth area. This paper aims to establish
the basis for a sediment management plan directed to offset the effects of the sediment delivery deficit of the Ebro delta.
Main Features A new management plan named ‘Integrated Plan for the Protection of the Ebro Delta’ (PIPDE) is being presently elaborated in
order to develop sustainable management of the Ebro River and delta through an integrated management of water, sediment and
habitats, in order to achieve European Union (EU) Water Framework Directive (WFD) requirements. Among other aspects, the plan
aims to restore the sediment flux of the lower Ebro River by means of both the removal of the sediment trapped behind the
dams and the transport of the sediment downstream of the reservoirs to the river mouth and delta plain.
Results Preliminary studies show that the ‘flushing flood’ method has lower costs and is the most adapted method to transfer the sediments
retained into the Riba-Roja dam. The required sediment load to stop coastal retreat in the mouth area and to compensate relative
sea level rise represents 10 times the present suspended load (0.021 g/l), but is 10 times lower than the total volume of
sediment delivered to the sea under natural conditions. Sediment delivery to the delta plain can be accomplished through the
rice irrigation system, a method used prior to dam construction.
Discussion Problems of achieving a sustainable management of water and sediment are mostly linked to reservoir management. Technical
problems associated with by-passing sediments through the reservoirs can be solved through operational and structural changes.
Benefits of sediment flow recovery are multiple, including maintenance of the reservoir capacity, possible decline of invasive
species, reduction of elevation loss and coastal retreat in the delta.
Conclusions The partial restoration of sediment fluxes in the lower Ebro River and its delta is technically feasible and environmentally
desirable, but further detailed studies need to be carried out before the plan can be implemented.
Perspectives Overall, the sustainability of the lower Ebro River and delta can only be guaranteed by the implementation of a new reservoir
management concept where the ecological and morphological values, as well as the economical and social values, have to be
taken into consideration. 相似文献
8.
Sara Peres M. Clara F. Magalhães Maria Manuela Abreu Sara Leitão Ana Santos Maria José Cerejeira 《Journal of Soils and Sediments》2016,16(5):1612-1624
Purpose
Wastes from a former Portuguese steel plant were deposited between 1961 and 2001 on the riverbank of a tributary of the Tagus River creating a landfill connected to the river, posing a potential contamination risk to the Tagus estuary ecosystem. This study aims to assess the transfer of chemical elements from contaminated sediments to the estuarine water from cycles of sediment leaching so as to evaluate the ecotoxicity of the leachates, and to analyze the solid phases crystallized from those leachates.Materials and methods
Landfill sediment and estuarine water samples were collected during low tide. Sediment samples were analyzed for pH, electric conductivity (EC), Corg, NPK, and iron oxides. Leaching assays (four replicates) were done using estuarine water (200 cm3/replicate) and 1.5 kg of sediment per reactor. Each reactor was submitted to four leaching processes (0, 28, 49, and 77 days). The sediment was kept moist between leaching processes. Sediment (total (acid digestion) and available fraction (diluted organic acid extraction-Rhizo)) elemental concentrations were determined by inductively coupled plasma–instrumental neutron activation analysis (ICP/INAA). Leachates, and estuarine and sediment pore waters were analyzed for metals/metalloids by ICP/mass spectrometry (MS) and carbonates/sulfate/chloride by standard methodologies. Ecotoxicity assays were performed in leachates and estuarine and pore waters using Artemia franciscana and Brachionus plicatillis. Aliquots of the leachates were evaporated to complete dryness (23–25 °C) and crystals analyzed by X-ray powder diffraction (XRD).Results and discussion
Sediment with pH?=?8 and high EC and Corg was contaminated with As, Cd, Cr, Cu, Pb, and Zn. The element concentrations in the available fraction of the sediment were low compared to the sediment total concentrations (<1 % for Rhizo extraction). The concentrations of potentially hazardous elements in the estuarine water were relatively low, except for Cd. Concentrations of hazardous elements in the leachates were very low. Calcium, K, Mg, Na, and chloride concentrations were high but did not vary significantly among the four leaching experiments. Total concentrations of carbonate were much higher in leachates than in estuarine water. Both estuarine water and leachates showed negligible toxicity. Crystals identified in the solids obtained from the leachates by evaporation were halite, anhydrite, epsomite, dolomite, and polyhalite.Conclusions
The sediment showed the capacity to retain the majority of the potentially hazardous chemical elements. Remobilization of chemical elements from sediment by leaching was essentially negligible. The variation of total concentrations of Ca, carbonate, and sulfate in leachates indicates that the sediment contained reactive sulfides. Due to its composition, the sediment seems to be a dynamic system of pollution control, which should not be disturbed.9.
《Land Degradation \u0026amp; Development》2017,28(8):2527-2539
Soil erosion is a severe problem on China's Loess Plateau due to its fine‐grained soils and the increasing frequency of extreme rainfall events. Accordingly, this study used a 100‐year frequency rainstorm dataset to analyse sediment deposition and sources in a 27‐km2 catchment with a dam field area of 0·14 km2 based on the hypothesis that sediments were intercepted by the dam (before collapse) during the rainstorm event and deposited in the dam field. This study applied composite fingerprinting, which revealed the sediment source contributions and estimated sediment deposition. Sediment deposition (626·4 kg m−2) decreased linearly or exponentially with increasing distance from the dam. Composite fingerprints based on the optimal parameters revealed relative sediment contributions of 44·1% ± 25·5%, 37·7% ± 35·0%, 9·0% ± 11·4% and 9·2% ± 11·5% by bare ground, croplands, grassland and forests, respectively. The 5‐year cumulative sediment deposition from normal rainfall was 2·3 × 104 t less than the extreme rainstorm. Bare grounds and croplands were the dominant sediment sources following both the extreme rainstorm and normal erosive rainfall events but varied at different areas of the check‐dam. Erosion patterns and start times depended on land use type, thereby affecting sediment profiles in the dam field. Furthermore, severe erosion from bare ground that were all gully slopes and gully walls occurred throughout the rainfall, whereas grasslands and forest erosion occurred earlier and croplands later. Finally, extreme rainfall promoted mass wasting on slopes, gully slopes and gully walls, which are important in determining extreme rainstorm erosion pattern variation. This study aimed to reveal erosion pattern variation under extreme rainstorm events. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
10.
Urszula Aleksander-Kwaterczak Edeltrauda Helios-Rybicka 《Journal of Soils and Sediments》2009,9(1):13-22
Background, aim, and scope Elevated levels of heavy metals in the aquatic and soil systems can be caused by the weathering of mineralized rocks. This
enrichment is often considerably enlarged by historical and current mining and smelting activities. In Poland, the most contaminated
river systems are those in the Silesia region. The metalliferous ore mining and smelting industries have been the main sources
of heavy metal pollutions over the last 100–170 years. The previous and present studies have shown very high concentrations
of heavy metals in the bottom sediments of the Mala Panew River, the most polluted tributary of the Oder River. The main objective
of this work was to study temporary changes of selected metal (Zn, Pb, and Cd) concentrations in upper layer of bottom sediments
at the measuring point near the outlet of the Mala Panew River into the Oder River, and to determine the vertical distribution
of the metals in the sediment cores from the most polluted middle part of this river. The mobility of the metals and their
potential bioavailability were assessed based on metal partitioning in the sediments and metal concentrations in pore waters.
The presented data were compared with metal concentrations in aquatic sediments from similar historical mining and smelting
sites in Poland and other countries.
Methods The upper layer of bottom sediment samples from the same Mala Panew River measuring point were collected six times in the
period 1997–2005, while five sediment cores were collected once from the middle course of Mala Panew River in 2006. Abiotic
parameters such as pH and Eh have been determined in situ. Metal contents were determined in the <20 and <63 μm size fractions
of sediments after digestion in a microwave oven with aqua regia or concentrated nitric acid. Metal mobility was assessed
in the selected sediment cores by the chemical forms of metals (sequential extraction method) and their concentrations in
pore waters were investigated.
Results The concentrations of Cd, Pb, and Zn in the upper layer of sediments varied, depending on both the season and the year of
sampling. Their mean concentrations (from six samplings) are [mg/kg]: Zn 1,846, Pb 229 and Cd 73. The metal concentrations
in the sediment cores varied with the depth in the range of [mg/kg]: 0.18–559 for Cd, 26.2–3,309 for Pb and 126–11,153 for
Zn, although the highest accumulations generally could be observed in the deeper layers. The most mobile metal fractions,
i.e., exchangeable, carbonate and easily reducible fractions, are typical of Zn and Cd. Cadmium was found to be the most mobile
metal and its relative contribution ranges from 84 to 96%, while in the case of Zn it ranged from 45 to 94%. Lead is mainly
associated with the moderately reducible fraction (30–60%). Relative contributions of metal chemical forms slightly vary with
the depth in the sediment profile. The results obtained for the pore water samples show very high concentrations of the metals
studied, especially in the case of Cd (31–960 μg/dm3) and Zn (300–4,400 μg/dm3).
Discussion Accumulation of Cd, Pb, and Zn in the upper layer of the bottom sediments and in the sediment core samples from the Mala Panew
River is very high, considerably exceeding the local geochemical background. High contributions of mobile Cd and Zn and the
toxicity of cadmium can cause environmental risk. Our measurements also suggest that mobile metals can migrate into groundwater,
whereas the groundwater itself can leach some chemicals from river sediments, because of a relatively high water table in
the study area, especially during rainfall periods. Comparison of the results obtained with the literature data from the last
decade shows that the concentrations of Cd and Zn in the sediments from the Mala Panew River are the highest among other submersed
sediments in Poland and other regions (e.g., the Mulde River, Germany).
Conclusions The Mala Panew River is one of the most polluted rivers when compared with similar historical mining and smelting areas in
Poland and elsewhere. The sediments studied are strongly polluted with the metals analyzed. In the upper layer of the bottom
sediments there has been no reduction of Zn and Cd amounts over the last decade, which could suggests a long-term migration
and a secondary contamination. Considerably higher accumulations of metals in overbank sediment cores and in the deeper core
section could result from strong contamination in previous decades and translocation of Cd and Zn (secondary pollutants).
The relatively high concentrations of the two metals in pore waters support these findings. Cadmium is crucial in the environmental
risk assessment because of its high mobility and toxicity. These data are important for water/sediment management in the transboundary
Oder River catchment, situated in Poland, Germany and the Czech Republic.
Recommendations and perspectives It is important to assess mobility phase and pore water in the contaminated historical aquatic sediments. Such studies may
help explain the changes, which take place in the sediment layers as well as at the water–sediment interface. Obtained results
should be used for the risk assessment of the historical contaminated sediments at the local river-basin scale. The treatment
of contaminated sediments, e.g., dragging activity, should be considered as very important in management strategies in order
to avoid remobilization of metals. 相似文献
11.
Mobility of trace metals associated with urban particles exposed to natural waters of various salinities from the Gironde Estuary, France 总被引:1,自引:1,他引:0
Jörg Schäfer Stefan Norra Daniel Klein Gérard Blanc 《Journal of Soils and Sediments》2009,9(4):374-392
Background, aim and scope Urban systems are hot spots of environmental pollution caused by manifold anthropogenic activities generating traffic-related,
industrial and domestic emissions. Besides air, soil and groundwater pollution, pollution of surface water systems is of major
concern because they are often (ab)used to export waste of various consistence out of urban areas and become contaminated
on varying scales. The Gironde Estuary (southwest France) is affected by various anthropogenic contaminations derived from
historic polymetallic pollution mainly due to former mining and ore-treatment and, additionally, from agriculture and urban
areas. Although detailed knowledge is available on the impact of mining and anthropogenic activities on the water quality
of the Gironde Estuary, almost nothing is known on the urban impact, even though the Garonne Branch which is one tributary
of the Gironde system crosses the large urban agglomeration of Bordeaux. The present work links urban geochemistry and estuary
research and aims at evaluating the mobility of potentially toxic trace elements (Cd, Cu, Zn, V, Co, Mo, Pb) associated with
urban particles under estuarine conditions owing to the particles' role as potential vectors transporting urban pollutants
into the estuary. For this, environmentally available fractions of trace elements in representative urban particles (urban
dust, road sediment, riverbank sediment, construction materials) from the city of Bordeaux were extracted by natural estuarine
waters of varying salinities and compared to commonly applied HNO3 extractions.
Materials and methods For the assessment of the urban particles' contribution to the pollution of the Gironde/Garonne system, various particle types
were sampled in Bordeaux: road sediments, urban bulk deposition, construction materials (concrete, asphalt, tile and gravel)
and flood sediments. Potentially environmental available fractions of Cd, Cu, Zn, V, Co, Mo and Pb were extracted by means
of concentrated HNO3, estuarine freshwaters and waters of two different salinities (S = 15 and S = 31). Analysis of trace elements was carried out by means of quadrupole inductively coupled plasma-mass spectrometry. Furthermore,
single particles from road sediments were characterised with scanning electron microscopy (SEM).
Results SEM analysis clearly showed that some particles contained fairly high concentrations of potentially toxic trace elements.
Extractions of materials investigated by varying acidities and salinities documented that the potentially bioavailable fractions
extracted by concentrated HNO3 may cover wide concentration ranges. Natural estuarine waters of various salinities (S = 0.5; S = 15; S = 31) extracted high proportions of Co, Ni, Cu, Zn and Cd from urban particles, especially for high-salinity water (S = 31). Extractions with freshwater revealed the lowest concentrations of desorbed trace elements. Particulate Mo, Pb and
V showed similar or lower mobility in saline water compared with freshwater, depending on the sample type.
Discussion Trace element mobility in estuarine waters varied according to the type of urban particles and depended on salinity for Co,
Ni, Cu, Zn and Cd. This is of high importance for towns located directly at the coast or for cities like Bordeaux, where water
courses crossing the agglomerations are connected to saline water masses. Since trace elements desorbed from particles in
saline waters may become highly bioavailable, they bear a potential risk for organisms. Comprehensive studies on the behaviour
of urban particles in estuarine waters and the related potential environmental impact are still missing.
Conclusions Saline waters mobilise relatively high amounts of Co, Ni, Cu, Zn and Cd from urban particles suggesting considerable metal
fluxes from riverine urban systems into coastal waters. Although estimates of trace metal inputs by urban bulk deposition
(urban dust) and other types of urban particles are preliminary for Bordeaux and may bear important uncertainties due to several
assumptions and extrapolation to the annual timescale, the orders of magnitude are probably realistic. Thus, these fluxes
are not negligible and need (1) further and improved observation and (2) to be taken into account in both mass budgets at
the estuary scale and emission control strategies.
Recommendations and perspectives New approaches combining geochemical and mineralogical characterisation of single urban particle types help identify their
role in metal emission into the environment and develop potential limitation strategies (e.g. the ban of priority pollutants
in tyres, etc.). Therefore, prioritisation of urban particle sources in terms of fluxes, reactivity of associated pollutants
and feasibility of emission reduction is strongly recommended. Coastal cities should integrate extractions of urban particles
with saline water into their environmental monitoring programs owing to the fact that saline conditions might cause efficient
desorption of potentially toxic trace elements. In continental cities, winter salting is likely to induce intense mobilisation
of metals from road sediments that may then reach the aquatic environment, instead of being retained in runoff decantation
reservoirs followed by subsequent disposal/treatment with road sediments. However, also particles from continental cities
reach coastal waters via rivers and have to be assessed with respect to trace metal desorption under various salinities. There
is a strong need for the quantification of fluxes and for the identification of carrier phases and reactivity of metals exported
from urban areas to aquatic systems. 相似文献
12.
The assessment of sediment screening risk in Venice Lagoon and other coastal areas using international sediment quality guidelines 总被引:3,自引:0,他引:3
Sabine E. Apitz Andrea Barbanti Alberto Giulio Bernstein Martina Bocci Eugenia Delaney Laura Montobbio 《Journal of Soils and Sediments》2007,7(5):326-341
Background, Aims and Scope A number of studies carried out in recent years have shown the presence of a wide range of contaminants in the Venice Lagoon.
It is important to have a good understanding of the ecological quality of Venice Lagoon sediments, in order to: i) define
and locate areas where a threat to the environment is present and therefore an intervention is needed (i.e. in situ assessment and management); and ii) define sustainable and environmentally correct ways of managing sediments which are to
be dredged for navigational purposes or in relation to other interventions (i.e., ex situ management).
Methods To examine how various regional and international SQGs ‘classed’ screening risk in Venice Lagoon sediments, data on median
contaminant levels in surface sediments in Venice Lagoon resulting from a literature review were compared to a range of local
and international sediment quality guidelines (SQGs). Then data on sediment contaminant levels in various areas and sub-basins
of Venice Lagoon (main Lagoon, Porto Marghera and Venice City Canals) and in other regional and international transitional
and coastal ecosystems with various levels of human impact (urbanization and industrialization) were evaluated based upon
a selected consensus-based SQG. Finally, screening sediment quality for all of Venice Lagoon was mapped and contoured, relative
to this consensus-based SQG and briefly compared with direct toxicity measurement through a battery of bioassays.
Results SQGs allow the sediment areas to be put in terms of potential, or screening, risk. Although there were some differences depending
upon which specific SQGs were applied, the Venice SQGs and other international SQGs provided the same general picture of screening
risk in Venice Lagoon despite geographic differences. Venice Lagoon South has the lowest screening risk levels, Venice Lagoon
Central/North has the highest (and is nearest to the Porto Marghera and Venice City Canals sites).
Discussion The Venice Lagoon sediments have hazard quotients on the low end of the range of moderately urbanized and industrialized sites
and higher than background case studies reviewed. Hg levels in the Venice Lagoon were generally higher than equivalent sites,
while other contaminants were either equivalent or lower. In Porto Marghera (PM) and Venice City Canals (VC), for many contaminants
of interest, PM, and for some, VC sediments have the highest levels of any case study reviewed. Ranges are high, so in all
cases, remedial or disposal decisions should be based upon site-specific (and preferably tiered) data.
Conclusions The use of hazard quotients makes it possible to compare screening risks due to different mixes of contaminants within and
between sites, but results should be interpreted with caution. How these sites rank when compared to some of the other highly
industrialized sites depends upon how data are synthesized and communicated. Actual risk must be evaluated using a weight
of evidence (WOE) approach, as site-specific bioavailability and background levels will differ both regionally and internationally.
Recommendations and Perspectives Whilst there are subtle differences, the current Venice sediment classifications (A, B and C) ‘performed’ in a similar manner
to SQGs in similar classes, suggesting that regions of Venice Lagoon would not be classified much differently if other SQGs
such as TEL, ERL, PEL, ERM or AET were adopted. The Italian sediment quality objectives, on the other hand, are significantly
more conservative than any other SQGs examined, with the exception of the Flemish Reference values. A number of European nations
are considering criteria based upon contaminant levels in relatively pristine modern sites, or based upon derivations of historical
(pre-anthropogenic) contaminant levels. When used as a standard, such an approach lacks discriminating power, designating
almost all sediments within an urbanized or industrialized region as of concern, or even, in many cases, mandating action
or prohibiting various management approaches in a large percentage of sediments. While generally based upon the laudable desire
to return sites to unimpacted levels, there is a risk that overprotective criteria have the opposite effect: by designating
too large a percentage of sediments as requiring management or control, limited resources may be improperly allocated. Which
set of SQGs is most ‘appropriate’ for the Venice Lagoon sediments depends upon the questions being asked. However, the Venice
classifications are currently being used as pass-fail criteria, without consideration of site-specific conditions. The fact
that they performed similarly to SQGs in similar classes suggests that any work to develop more site-specific SQGs (with the
same general decision classes) would probably not make much difference in how sediments were ultimately classified and managed
unless the fundamental approach was changed from a pass-fail to a tiered and WOE approach integrated in a comprehensive decision
framework. For Venice Lagoon, and for other regions, although SQGs should be developed with care, in a scientifically defensible
and risk-based manner, an equally or more important issue to be addressed is their role in overall decision frameworks.
ESS-Submission Editor: Dr. Marc Babut (marc.babut@cemagref.fr) 相似文献
13.
Jürgen Weber Jupp Kreutzmann Anita Plantikow Evelyn Claus Werner Manz Peter Heininger 《Journal of Soils and Sediments》2006,6(2):84-91
Goal, Scope and Background Numerous xenobiotics released into surface waters are transferred to suspended particulate matter and finally attached to
sediments. Aquatic organisms may be exposed to them by direct particle feeding, by physical contact with contaminated surfaces
as an exposure route, and by the uptake of dissolved contaminants after equilibration via the free water phase. In order to
assess potential sediment toxicity, each of these exposure routes has to be addressed. This paper presents a newly developed
particle contact assay that uses the fermentation performance of a specific Saccharomyces cerevisiae strain for the assessment
of toxic effects in sediments. The test procedure is based on the characteristic feature of growing yeast cells to attach
to sediment particles, which are also relevant for the accumulation of contaminants. The physical contact with lipophilic
contaminants mirrors an exposition pathway for the direct uptake into the cells. In order to quantitatively characterize the
toxic effects of particle attached pollutants on the fermentation performance, unpolluted native reference sediment was spiked
with representatives for widely distributed anthropogenic contaminants.
Methods Saccharomyces cerevisiae was established as sensitive eukaryotic microorganism for the ecotoxicological assessment of particle
attached anthropogenic contaminants in freshwater sediments. For this purpose, yeast cells were cultivated in sediment samples
and the resulting fermentation performance was continuously measured. Sediments artifically spiked with HCB, PCB, g-HCH, DDT,
and benzo(a)pyrene and solutions of each contaminant were comparatively investigated by means of their adverse effects on
yeast fermentation performance. Additionally, four native river sediments characterized by increasing levels of pollution
were assessed by the yeast particle contact assay, and simultaneously by standard aquatic tests with algae, daphniae, and
luminescent bacteria using pore water and elutriates. Results of the bioassays were related to specific sediment contamination
with respect to metals and organic priority pollutants.
Results and Discussion In sediments spiked with PCB and benzo(a)pyrene fermentation, performance was affected extensively below concentrations inhibiting
fermentation in contaminant solutions. This suggests a high efficiency of the exposure route by physical contact. The fermentation
performance was only slightly affected by single lipophilic pollutants, whereas mixtures of individually spiked sediments
caused critically reduced fermentation performance suggesting additive synergistic effects. Native river sediments modestly
to critically polluted by hazardous organic compounds lead to a slightly to dangerously reduced fermentation performance in
the yeast contact assay. These inhibitory effects were much less pronounced in the standard bioassays conducted with algae,
daphniae and luminescent bacteria, applying pore waters and elutriates as sample matrices. Using pore water, inhibition was
measured only in the most polluted sediment, elutriates lead to a slight inhibition of the algal growth in the undiluted sample
only. These results indicate an improved sensitivity of the yeast particle contact assay compared to the standard assays,
due to uptake and physical cell contact as additional routes of exposure.
Conclusion The yeast particle contact assay is a valuable tool for the assessment of ecotoxicological potential in freshwater sediments.
Since the assay addresses physical contact as an exposure route, it indicates bioavailability of lipophilic compounds in sediments.
Outlook The sensitive indication of bioavailable contaminants associated to sediment particles by the newly developed yeast particle
contact assay recommends it as a complementary microbial bioassay in a test battery for assessing major pathways of contaminants
in whole sediments. 相似文献
14.
Walter Martinotti Marina Camusso Luigi Guzzi Luisa Patrolecco Maurizio Pettine 《Water, air, and soil pollution》1997,99(1-4):325-332
C and N content, C/N (atomic) ratio, and C and N isotopic composition (δ13C and δ15N) were determined on suspended particulate matter and sediment samples obtained from riverine, estuarine and marine environments in two cruises (September 1995 and March 1996) in the Po estuary (Italy). Isotopic tracers of C and N, reported for the first time for this environment, gave information on sources of organic matter and their distributions. An end-member mixing model based on δ13C values was applied to estimate the relative importance of riverine and marine sources of organic matter in suspended particulate matter and sediments. 相似文献
15.
S. P. Leatherman 《Water, air, and soil pollution》1996,92(1-2):149-157
Coastal erosion is a worldwide problem; it is estimated that over 70% of the world's beaches are currently experiencing erosion (Bird, 1985), and this number may approach 90% in the United States. Almost every conceivable form of shore protection has been attempted in the United States, including construction of seawalls, groins, and jetties as well as beach nourishment. The principal approach to protecting coastal property and maintaining recreational beaches in the United States today is beach nourishment. Engineering structures such as groins and seawalls have often been shown to have detrimental effects on adjacent beaches. Also, their construction and maintenance costs are quite high. Therefore, coastal communities have come to rely on a “soft” engineering solution — beach nourishment —because it is environmentally sound, aesthetically pleasing, and, so far, economically feasible. However, global warming and accelerated sea level rise will cause more rapid rates of beach loss and could make even this alternative too costly for many resort areas along the U.S. shoreline. The cost to nourish all the major recreational oceanic beaches in the United States was estimated based on various sea level rise scenarios. The beach nourishment approach involves placing enough sand on the beach to maintain stable (nonretreating) conditions in response to rising sea level. The quantity of sand required to “hold the line” is evaluated under various sea level rise scenarios from the baseline scenario to the 1-m estimate of the Intergovernmental Panel on Climate Change. Beach nourishment is not a practical alternative for most Pacific island nations because sand is a scarce resource. In fact, beaches are often mined for sand for construction, contributing to beach erosion. For mainland countries, beach fill projects are more practical. Singapore was one of the first countries to use this technology in combination with building offshore breakwaters to form artificial headlands. As Western style sunbathing and the overall popularity of beaches for recreation continue to grow, beach nourishment can be expected to become a more common way to deal with sea level rise induced coastal erosion for highly developed beach resort areas. 相似文献
16.
Background, Goal and Scope To date, standardised bioassays for the assessment of the ecotoxicological potential in sediments and dredged material use
test organisms like bacteria, algae and crustaceae. This paper presents the development and application of a novel sediment
contact test (whole sediment) withMyriophyllum aquaticum, a representative of rooted aquatic macrophytes. The aim of the present study is to demonstrate the value of a sediment contact
test with rooted macrophytes as a supplement to existing test batteries in order to improve the assessment of sediment toxicity.
Methods The newly developed sediment contact test withMyriophylhim aquaticum was applied to natural whole sediments. For performing the test, whorls ofMyriophyllum aquaticum were directly planted in the native sediment and incubated in the light at 24°C (cf. section results and discussion). The
end points of the test were the number of the shoots and the fresh weight of the whole plants. The duckweed growth inhibition
test withLemna minor according to ISO/DIS 20079 was performed in pore waters from sediment samples. The results of the sediment contact test withMyriophyllum aquaticum were compared with each other and with those of the aquatic duckweed test.
Results and Discussion A test protocol for the new plant-based sediment contact test using the aquatic plantMyriophyllum aquaticum as an indicator was developed. The best control sediment proved to be the OECD sediment (OECD 207). A test period of 10 days
appeared to be sufficient for the test. The increase of biomass and the derived growth rate were found to be the most suitable
evaluation parameters. The growth behaviour ofMyriophyllum aquaticum differed depending on the origin of sediments. Therefore, plant-affecting contamination, that is bound in sediments, was
indicated.
Conclusions The novel sediment contact test withMyriophyllum aquaticum can indicate phytotoxic effects in sediments. Therefore, it allows a better assessment of the overall-toxicity in whole sediments.
Recommendations and Outlook The sediment contact test withMyriophyllum aquaticum is a valuable tool for the evaluation of the ecotoxicological risk potential of waters and sediments. It should become a
complement to a standardised test battery generally used for the assessment of sediment toxicity. 相似文献
17.
Kate L. Spencer Andrew J. Manning Ian G. Droppo Gary G. Leppard Thomas Benson 《Journal of Soils and Sediments》2010,10(7):1401-1414
Purpose
Cohesive sediment tracers have been developed to improve our understanding of fine sediment transport in the aquatic environment. However, there is little understanding of their physical and dynamic characteristics compared to the natural sediments they are intended to mimic. This work focuses on a labelled clay mineral tracer examining its dynamic characteristics and determining whether it flocculates and interacts with natural estuarine mud. 相似文献18.
Goal, Scope and Background. Based on a bioassay battery covering only primary producers and consumers as well as degraders,
the potential ecological hazard of sediments to vertebrates cannot be estimated comprehensively. Therefore, there is an urgent
need to develop and standardize integrated vertebrate-based test systems for sediment investigation strategies. Whereas vertebratebased
in vitro systems have frequently been used for the investigation of aqueous samples, there is a significant lack of whole sediment
assays. Thus, the purpose of the present study was: (1) to develop a rapid and reliable, but comprehensive method to investigate
native sediments and particulate matters without preceding extraction procedures; (2) to compare the hazard potential of solid
phase sediments to the effects of corresponding pore waters and organic extracts in order to characterize the bioavailability
of the particle-bound pollutants; and (3) to relatively evaluate the embryotoxic effects of sediments from the catchment areas
of the rivers Rhine, Neckar and Danube.
Methods (or Main Features). To investigate the toxicity of sediment samples on vertebrates, the standard embryo toxicity test with the zebrafish (Danio rerio; Hamilton-Buchanan 1922) according to DIN 38415-6 was modified with respect to exposure scheme and toxicological endpoints.
Sediments from the catchment area of the Neckar River were assessed using pore waters, acetonic extracts and native sediments
in order to get inside into the potential bioavailability of particle-bound pollutants. A comprehensive test protocol for
the investigation of native sediments in the embryo toxicity test with the zebrafish is presented.
Results and Discussion. The fish embryo assay with Danio rerio can be carried out with both aqueous and organic sediment extracts as well as native (whole, solid phase) sediment samples.
Elongation of exposure time from 48 to up to 196 h significantly increased the mortality. Using the fish egg assay with native
sediments, a broad range of embryotoxic effects could be elucidated, including clear-cut dose-response curves for the embryotoxic
effects of contaminated sediments; in contrast, absence of embryotoxic effects could be demonstrated even for the highest
test concentrations of unpolluted sediments. With native sediments, embryotoxicity was clearly higher than with corresponding
pore waters, thus corroborating the view that — at least for fish eggs — the bioavailability of particle-bound lipophilic
substances in native sediments is higher than generally assumed. The relative ranking of sediment toxicity was identical using
both native sediments and sediment extracts, EC20 values of the latter, however, being eight time lower higher than with the native sediments. A comparison of the embryo toxic
effects of samples from the Neckar area with locations along the Rhine and Danube rivers elucidated a broad range of results,
thus indicating different levels of contamination.
Conclusions. A modified protocol of the zebrafish embryo test allows the assessment of sediment toxicity in both aqueous extracts and native
sediments. The isolated investigation of pore waters may result in a clear-cut underestimation of the bioavailability of lipophilic
particle-bound substances (as determined by native sediments).
Recommendations and Perspectives. The zebrafish embryo test with native (whole, solid phase) sediments appears very promising for the evaluation of the bioavailable
fraction of lipophilic particle-bound substances and can therefore be recommended for the evaluation of vertebrate toxicity
in tiered sediment test strategies and dredging directives such as the HABAB-WSV. Whereas acetone extracts may be tested as
a rough estimation of embryotoxicity, native sediment samples will provide a more comprehensive and realistic insight into
the bioavailable hazard potential 相似文献
19.
民勤县固定与半固定沙丘粒度特征分析 总被引:1,自引:0,他引:1
沉积物粒度特征可以反映沉积物形成的沉积环境、沉积过程和搬运营力、搬运过程等信息。以民勤县西北部半固定与固定沙丘为研究对象,运用粒度分析方法,对其表层沉积物进行了系统采样分析。结果表明,半固定、固定沙丘的粒度组成均以细沙为主,极细沙次之,二者粒级级配相似,含量却有不同。半固定沙丘平均粒径为2.69Φ,中等分选近对称中等峰度分布;固定沙丘平均粒径为2.66Φ,中等分选近对称尖窄峰度分布。半固定、固定沙丘平均粒径与偏度存在二次多项式关系(R2=0.404 1);峰度与平均粒径、标准离差、偏度呈不显著线性正相关关系(0.550,0.496,0.356);标准离差与平均粒径、偏度之间无相关性。 相似文献
20.
Rate Andrew W. Robertson Alistair E. Borg Audrey T. 《Water, air, and soil pollution》2000,124(1-2):155-168
Estuarine systems adjacent to urban areas are at risk of contamination by contaminants from anthropogenic sources, such as heavy metals. We anticipated that the sediments of the Swan River estuary, which runs through metropolitan Perth in Western Australia, would show metal contamination related to industrialization and inputs of stormwater. Total Cu, Pb and Cd concentrations, and Cu, Pb, Cr and Zn inoperationally-defined fractions, were determined inseparate sampling exercises in near-shore sediments ofthe upper Swan River estuary.Total metal concentrations in sediments were not high (maximum values of 297 mg kg-1 for Cu, 184 mg kg-1 for Pb and 0.9 mg kg-1 for Cd) when compared with Australian environmental assessmentguidelines for soils. On the basis of linear regressions between sediment metal concentrations andphysicochemical properties of the sediments (pH, organic carbon, particle size distribution), no single parameter could explain the variation in metal concentrations for all metals. Sediment organic carbon content was positively correlated with Cu concentration; Cu concentrations also increased significantly with increasing clay content anddecreasing sand content. Pb concentrations showed a significant increase with increasing sediment pH, and were approximately three-fold higher in sediments adjacent to stormwater drain outfalls than in sediments remote from drains; no such effect was observed for Cu or Cd. No effect of distance downstream was observed. Sequential extraction of sediments showed that most of the metals were in relatively immobile forms, for example bound to Feoxides, or only extractable by aqua regia. The enhanced concentrations of Pb near stormwater outfalls suggest that vehicle-derived Pb may be an important contributor of Pb to the estuary. 相似文献