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1.
Tereza Novakova Tomas Matys Grygar Ondrej Babek Martin Famera Martin Mihaljevic Ladislav Strnad 《Journal of Soils and Sediments》2013,13(2):460-473
Purpose
Regional contamination of southern Moravia (SE part of the Czech Republic) by trace metals and magnetic particles during the twentieth century was quantified in fluvial sediments of the Morava River. The influence of local pollution sources on regional contamination of the river sediments and the effect of sampling site heterogeneity were studied in sediment profiles with different lithologies.Materials and methods
Hundreds of sediment samples were obtained from regulated channel banks and naturally inundated floodplains and proxy elemental analyses were carried out by energy dispersive X-ray fluorescence spectroscopy (ED XRF) and further calibrated by inductively coupled plasma mass spectrometry (ICP MS). Magnetic susceptibility was determined as a proxy for industrial contamination. The age model for the floodplain sediments was established from 137Cs and 210Pb dating. Trace metal contamination was assessed by establishing the lithological background values from floodplain profiles and calculating enrichment factors (EF) of trace metals (i.e. Pb, Zn, Cu) and magnetic susceptibility for the entire study area.Results and discussion
Channel sediments are unsuitable for the reconstruction of historical regional contamination due to their lithological heterogeneity and the “chaotic” influence of local sources of contamination, as well as the possibility of geochemical mobility of pollutants. On the other hand, sediments from regulated river banks qualitatively reflected the actual, local contamination of the river system.Conclusions
This approach allowed us to distinguish the influence of local sources of contamination by comparison with more spatially averaged contamination signals from distal floodplain profiles. The studied area is weakly contaminated (EF ～1–2), while individual sediment strata from regulated channel banks reflect local sources of contamination and contain up to several times higher concentrations of trace metals. 相似文献2.
Marie Smutná Klára Hilscherová Veronika Pašková Blahoslav Maršálek 《Journal of Soils and Sediments》2008,8(3):154-164
Background, aim, and scope
Restoration of lakes and reservoirs with extensive cyanobacterial water bloom often requires evaluation of the sediment quality. Next to the chemical analysis of known pollutants, sediment bioassays should be employed to assess toxicity of the present contaminants and to make predictions of associated risk. Brno reservoir in the Czech Republic is a typical example of water bodies with long-term problems concerning cyanobacterial water blooms. Comprehensive assessment of reservoir sediment quality was conducted since successful reservoir restoration might require sediment removal. An important part of this survey focused on an examination of the utility of Tubifex tubifex and its sublethal biochemical markers for the assessment of direct sediment toxicity.Materials and methods
This complex study included chemical analysis of contaminants (heavy metals, organic pollutants), ecotoxicity testing of sediment elutriates (tests with Daphnia magna, Pseudomonas putida, Sinapis alba, Scenedesmus subspicatus), and other parameters. We have tested in more detail the applicability of T. tubifex as a test organism for direct evaluation of contact sediment toxicity. Survival tests after 14 days of exposure were complemented by an assessment of parameters serving as biomarkers for sublethal effects [such as total glutathione content (GSH), activities of the enzymes glutathione transferase (GST), glutathione peroxidase (GPx), and glutathione reductase (GR)]. The data matrix was subjected to multivariate analysis to interpret relationships between different parameters and possible differences among locations.Results
The multivariate statistical techniques helped to clearly identify the more contaminated upstream sites and separate them from the less contaminated and reference samples. The data document closer relationships of the detected sediment contamination with results of direct sediment exposure in the T. tubifex test regarding mortality but namely regarding the sublethal endpoints rather than the results obtained with other test organisms exposed to sediment elutriates. Aside from the reduction in T. tubifex survival, the sediments with organic pollution caused an increase in glutathione content and increased activities of glutathione S-transferase and glutathione peroxidase in the exposed T. tubifex worms.Discussion
Results of our study confirm the suitability of T. tubifex for toxicity testing of raw waters and sediments. This longer-lasting direct contact test has proven more sensitive and appropriate to reflect a lower level of pollution than do the elutriate tests. Sensitive biochemical changes in T. tubifex, including an elevation in GSH levels and GST activities, reflect a general stimulation of detoxification metabolisms in the presence of xenobiotics. The results also suggest an important role of glutathione and related enzymes in detoxification processes and possible involvement of oxidative stress in toxicity mechanisms in benthic sediment-dwelling worms such as T. tubifex.Conclusions
The complex assessment has identified the more contaminated samples with locally increased concentration of organic pollutants and significant ecotoxicity. The direct sediment contact test with T. tubifex and especially the biochemical parameters corresponded better to the lower level of pollution than the other tests with sediment elutriates. Despite its greater time and cost demands, the direct sediment contact test can provide a more realistic picture of exposure.Recommendations and perspectives
Sediment bioassays should always be included as an integral part of the sediment quality assessment. The direct contact tests also take into account the more hydrophobic pollutants that are not easily available for the water elution but can still be accessible to the organisms. The T. tubifex test is a suitable option for contact sediment toxicity tests also because these animals show measurable sublethal biochemical changes that can be associated with this exposure. 相似文献3.
Fulvio Onorati Cristian Mugnai Marina Pulcini Massimo Gabellini 《Journal of Soils and Sediments》2013,13(2):474-487
Purpose
In order to assess sediment quality and to account for the great geochemical heterogeneity of Italian coasts, Local Sediment Quality Guidelines (LSQGs) have to be defined for specific portions of the coastline based on the approach developed by ICRAM–APAT (2007). This paper describes the application of LSQGs to the harbour of Fiumicino (Rome, Italy). The aims were to evaluate the quality of dredging sediments through an integrated chemical–ecotoxicological approach and to define suitable management options.Materials and methods
Thirty-eight sediment cores, covering the planned dredging depth, were collected in the study area and sliced into 92 sediment samples. Chemical analyses, including inorganic and organic contaminants as well as microbiological parameters, were carried out for all the samples. A bioassay battery composed by the bacterium Vibrio fischeri, the sea urchin Paracentrotus lividus and the alga Dunaliella tertiolecta was applied on one third of the samples. LSQGs were derived from chemical and ecotoxicological data of the harbour area, and were integrated with those from the identified dumping site. The Baseline Chemical Level, corresponding to an absent or unlikely ecotoxicological hazard, and the Limit Chemical Level, corresponding to a probable ecotoxicological hazard, were the LSQGs derived for each chemical.Results and discussion
A gradient of increasing contamination, moving inland due to urban and agricultural effluents, was observed. Ecotoxicological analyses, similar to microbiological ones, confirmed the poor sediment quality, with the exception of a sample located at the port entrance, where hydrodynamics flush sediment away from the site. Principal component analysis allowed a clear discrimination of three areas, each affected by a different contamination degree and influenced by many sources related to industrial, commercial and/or urban activities. Using LSQGs and the results of bioassays, it was possible to classify the sediment quality of the whole harbour area and to define the most suitable management options. It was found that Fiumicino harbour sediment was not suitable for either beach nourishment or for offshore dumping, with the exception of a negligible amount located at the port entrance. In turn, most sediment seemed to be suitable for disposal in a properly sealed confined disposal facility or for mechanical/chemical treatment.Conclusions
This case study provided useful insights for implementing the development of LSQGs for more realistic sediment management and will assist in promoting its application to harbour dredging at the local level. 相似文献4.
Kenneth Macrae Silje Kile Merete Grung Ketil Hylland 《Journal of Soils and Sediments》2012,12(6):921-932
Purpose
The highest concentrations of environmental contaminants are generally found in marine sediments, and there is a need for knowledge concerning how and whether they affect sediment-dwelling organisms. This study aimed to assess sublethal effects in Arenicola marina exposed to two sediments from a contaminated fjord and two reference locations with different sediment characteristics.Materials and methods
Duplicate contaminated sediments were used to investigate the robustness of current protocols for sediment testing. The two reference sediments, with different grain sizes and total organic carbon, were collected from the outer Oslofjord and the two contaminated sediments from Frierfjord. Polychaetes were exposed in quadruplicate sediment microcosms and sampled after 1, 2, 4 and 8?weeks of exposure. Oxidative stress resistance (total oxyradical scavenging capacity, TOSC) and components comprising the energy budget (cellular energy allocation, CEA) were determined for individual polychaetes.Results and discussion
Arenicola maintained and increased body weights over the initial 4?weeks of exposure in all groups, except in one reference sediment (Elle). There were no differences between treatments in the scavenging capacity (TOSC). The most striking difference in how polychaetes partitioned energy resources was a difference in lipid and carbohydrate allocations for Arenicola held in the contaminated sediments over the initial weeks. Cellular respiration appeared to increase in polychaetes held in the Elle sediment and decreased for polychaetes held in the two Frierfjord sediments by weeks?4 and 8. In the overall CEA, this was offset by increased energy per weight stored in the Elle group, which resulted in an overall positive CEA for polychaetes held in that sediment, whereas polychaetes in the other treatments were close to neutral. Although CEA would thus indicate that Elle polychaetes had good health status, their body weight also decreased significantly over the experimental period compared to other treatments, indicating an overall negative effect.Conclusions
This study has shown the importance of sediment characteristics when evaluating toxicity and how resource allocation can differ dramatically over a short time span in polychaetes held in similarly contaminated sediments. There were no clear effects of sediment contamination on CEA or TOSC in the polychaete A. marina. The findings are relevant for the design of both short- and long-term sediment studies. 相似文献5.
Catrina Cofalla Sebastian Hudjetz Sebastian Roger Markus Brinkmann Roy Frings Jan W?lz Burkhard Schmidt Andreas Sch?ffer Ulrike Kammann Markus Hecker Henner Hollert Holger Schüttrumpf 《Journal of Soils and Sediments》2012,12(3):429-442
Purpose
Flood events are expected to increase both in intensity and frequency due to climate change in the near future. From an environmental toxicology perspective, there is concern that such flood events could lead to the remobilization of contaminated sediment layers in rivers. The aim of this pilot study was to establish a novel and interdisciplinary framework combining methods of hydrodynamic engineering and ecotoxicological assessment to enable investigation of the potential risks associated with such remobilization events.Materials and methods
Formulated sediment was prepared according to OECD guideline 218 and spiked with a mixture of four polycyclic aromatic hydrocarbons (phenanthrene, chrysene, pyrene, benzo[a]pyrene) at concentrations of 3.3?C8.3?mg?kg?1 dry weight. Rainbow trout (Oncorhynchus mykiss) were exposed as test animals to re-suspended sediments in three out of five experiments. The experiments were carried out in an annular flume designed to investigate transport behaviour of fine-grained sediments. Several physicochemical (e.g. pH) and sedimentological (e.g. turbidity) parameters were measured to characterise environmental conditions and erosion behaviour of sediments. Furthermore, exposure concentrations were measured by means of an in vitro assay (7-ethoxyresorufin-o-deethylase (EROD), RTL-W1 cell assay) and chemical analysis.Results and discussion
Preparation and spiking of large amounts of formulated sediments were feasible but not practical. Successful spiking could be confirmed by the bioanalytical methods with the spiked sediments showing significantly elevated EROD induction compared to control sediments. Conditions within the annular flume remained stable throughout all experiments and were adequate to support rainbow trout. Flood events were successfully simulated, resulting in re-suspension of formulated sediment. Different erosion behaviours of sediments during the simulated flood events were observed and could be associated with changes in microbial composition of sediments due to differences in storage conditions. Therefore, maintaining constant storage conditions of formulated sediments is crucial to enable consistency and comparability among erosion experiments.Conclusions
This study clearly demonstrated the feasibility of a combined hydro-toxicological approach in support of the investigation of the potential ecotoxicological relevance of sediment re-suspension events. However, based on the results presented here, it is recommended to include additional physicochemical parameters, such as redox potential and conductivity, and to extend the experimental setup to natural sediments and different aquatic organisms. Future studies will use natural sediments containing representative microbial communities and extracellular polymeric substances to enable extrapolation from the annular flume to conditions in natural flowing waters. 相似文献6.
Characterization of sediment contamination patterns by hydrophobic pesticides to preserve ecosystem functions of drainage lakes 总被引：1，自引：1，他引：0
Wei Wang Laura Delgado-Moreno Jeremy L. Conkle Michael Anderson Christopher Amrhein Qingfu Ye Jay Gan 《Journal of Soils and Sediments》2012,12(9):1407-1418
Purpose
Many drainage basins are terminal recipients of hydrophobic contaminants such as pesticides. To minimize adverse effects of the contaminated sediments on wildlife, it is important to understand sediment contamination patterns. This study was conducted at the Salton Sea, which is a heavily polluted large lake in southern California, USA, with the purpose to identify areas with minimal contamination so as to support species conservation.Materials and methods
We investigated the horizontal and vertical distribution of 14 organochlorine pesticides (OCPs) and 12 currently used pesticides (CUPs) in playas at locations near the drainage outfalls. The data were subjected to spatial analysis using Kriging interpolation and converted to contour maps. Statistical comparisons were made among different areas, between different sediment depths, and between air-exposed and submerged sediments.Results and discussion
Various OCPs were found near two drainage inlets, with mean concentrations of 6?C30???g?kg?1 in air-exposed sediments and 3?C18???g?kg?1 in submerged sediments. Chlordane (detected frequency, DF?=?77?%) and DDT derivatives (DF?=?100?%) were among the most frequently detected OCP. Significantly higher concentrations were found in air-exposed sediments than in submerged sediments, and in subsurface sediments than in surface sediments (P?<?0.01), suggesting historical deposition and burial. Sediments at many locations exceeded the threshold levels for DDE. A total of seven CUPs were detected with the maximum ??CUPs concentration of up to 27???g?kg?1. Bifenthrin was the dominant CUP contaminant, representing more than 60?% of ??CUPs for most samples with the highest concentration of 26???g?kg?1.Conclusions
Findings from this study provide a snapshot of the spatial distribution in both horizontal and vertical directions of hydrophobic pesticides in a drainage-dominated lake, and such information and the method of investigation may be used for identifying areas of minimal contamination as alternative habitats for this and other impacted lakes. 相似文献7.
Andreas Zehnsdorf Heinz Seidel Petra Hoffmann Uwe Schlenker Roland A. Müller 《Journal of Soils and Sediments》2013,13(6):1106-1112
Purpose
A bioremediation process for sediments contaminated with heavy metals has been developed based on two core stages: (1) conditioning of dredged sludge using plants; and (2) solid-bed bioleaching of heavy metals from the resulting soil-like material using microbially produced sulfuric acid. In laboratory and pilot-scale tests, reed canary grass (Phalaris arundinacea) was found to be best suited for the conditioning process. To demonstrate the feasibility of conditioning in practice, a study on a larger scale was performed.Materials and methods
The sediment originated from a detritus basin of the Weisse Elster River in Leipzig (Saxony, Germany) and was polluted with heavy metals, especially with zinc and cadmium. The dredged sludge was a muddy-pasty, anoxic, and had a high organic matter content. The experimental basin (base area of 50?×?23 m) was filled with 1,400 m3 of sludge to a height of 1.2 m. Conditioning was carried out in five segments that were planted with pre-cultivated Phalaris plants at two plant densities, sowed with Phalaris seeds using two different seeding devices, and grown over by vegetation. Plant development and changing sediment characteristics were analyzed during two vegetation periods by harvesting plant biomass every 4 weeks and sampling sediment material at two different depths every 2 weeks over a total duration of 475 days.Results and discussion
At the end of the second vegetation period, the pre-cultivated Phalaris plants had reached a height of 2 m, compared to 1.8 m for the sowed Phalaris seeds. Regarding root penetration and the degree of sediment conditioning, the less expensive sowing techniques yielded similar results to planting pre-cultivated plants. The content of heavy metals in the Phalaris plants was below the permissible limits for Germany. The vegetation evapotranspirated large amounts of water from the sediment and transported oxygen into the anoxic sludge. The water content was reduced from 68 to 37 %. The muddy-pasty sludge turned into a soil-like oxic material with a high permeability to water. The oxidation of sediment-borne compounds lowered the pH from 7.3 to 6.0. Due to the high total precipitation in Saxony in the summer of 2010, a maximum of 65 % of the sediment was conditioned.Conclusions
The feasibility of the first core stage of the bioremediation process for sediments was demonstrated in practice by conditioning 1,400 m3 of dredged sludge using reed canary grass. To establish the proposed sediment treatment in practice, the applicability of the central core stage–solid-bed bioleaching of conditioned soil-like sediment–will also be tested at a larger scale. 相似文献8.
Sandro R. Urban Albertina X. R. Corrêa Carlos A. F. Schettini Paulo R. Schwingel Rafael M. Sperb Claudemir M. Radetski 《Journal of Soils and Sediments》2010,10(1):65-76
Purpose
Most of the information concerning the effects of contaminated sediments on estuarine organisms deals with the impacts of bed forming sediments. The ecotoxicological potential at the time of a dredging operation is more difficult to assess, and few studies have dealt specifically with resuspended contaminated sediments. The aim of this study was to determine whether release of contaminants through sediment resuspension during a dredging operation in the Itajaí-açu estuary (Brazil) changed the water quality classification and had an ecotoxicological impact on the near-field water column during the critical moment of this operation.Materials and methods
Waters from two sites (control and dredged sites) were analyzed for physicochemical parameters before, during, and after a dredging operation. In parallel, a short-term, sensitive battery of biotests (bacteria, algae, and daphnids) was performed with water samples before and during this operation according to the ISO bioassay protocols.Results and discussion
No short-term toxicity was observed with waters collected before or during the dredging operation. The results showed that desorption of contaminants from suspended particles of sediments with a low level of contamination during a dredging operation lowered the water quality in the near-field water column but that this did not promote significant acute toxicity effects on the organisms tested.Conclusions
More detailed studies are needed (e.g., the question of the reliability of biotests under turbulent, particle-rich conditions) to fully understand this complex issue regarding water column ecotoxicity during the whole dredging operation and to support decisions on the management of dredging activities.9.
M. Carmen Casado-Martinez Brian D. Smith Philip S. Rainbow 《Journal of Soils and Sediments》2013,13(2):429-440
Purpose
The purpose of this paper is to compare three approaches for providing information on the bioaccumulation potential of metals from contaminated sediments to the deposit-feeding polychaete Arenicola marina.Materials and methods
We present metal (Ag, As, Cd, Cu, Pb and Zn) bioaccumulation results from field-collected sediments quantified through direct measurements of bioaccumulated concentrations in A. marina over a period of 30 days under controlled laboratory exposures and compare these results with bioaccumulated metal concentrations in field-collected organisms from the same sites of collection of the sediments used in the laboratory exposures. For the metals for which model parameters are available (Ag, As, Cd and Zn), we also compare these results with biodynamic model predictions. We considered three UK estuaries characterised by a well-reported history of trace metal contamination and bioavailability in addition to the (control) site of collection of the worms.Results and discussion
The results from laboratory-exposed organisms showed that the standard 28-day exposure duration may be adequate to identify the potential for metal bioaccumulation in this polychaete at the sites considered here. However, the time course of bioaccumulated concentrations and the comparison with measured concentrations in field-collected worms show that a steady state has not been reached, confirming the need for extended exposure periods. The worms showed symptoms of stress in feeding and growth during the initial 10 days of exposure and subsequent partial recovery during the following 20 days, suggesting that stress was not always caused by sediment contamination but that it was likely associated with handling and acclimation. At this last stage of the exposure, a generalised biodynamic model was used to provide estimates of bioaccumulated metal concentrations and net accumulation rates in worms.Conclusions
The results of this study highlight the number of factors that should be considered for the interpretation of bioaccumulated metal concentrations in A. marina under laboratory exposures for contaminated sediment assessment, factors that appear to be common to most deposit-feeding polychaetes. A general biodynamic model proved to be a cost-effective method for an initial estimation of the extent and pattern of metal bioaccumulation under specified exposure conditions. 相似文献10.
Mari Luz García-Lorenzo María José Martínez-Sánchez Carmen Pérez-Sirvent 《Journal of Soils and Sediments》2014,14(10):1753-1765
Purpose
The objective of this work was to evaluate the effectiveness of a plant bioassay (Phytotoxkit®) for screening ecotoxicological risks in sediments affected by mining activities.Materials and methods
A total of 42 sediment samples affected by mining activities were studied, including 39 sediment samples from the Sierra Minera, Spain, an area affected by old extraction procedures, and three sediments from an area affected by opencast mining. These three samples were then mixed with limestone filler at 10, 20 and 30 %, providing nine stabilised samples. The total and soluble metal(loid) content (As, Cd, Cu, Fe, Pb and Zn) was determined in all samples, and the Phytotoxkit® bioassay was applied to determine the ecotoxicological effect of this procedure.Results and discussion
The stabilised material had a neutral pH and low soluble metal(loid) concentration, similar to that of samples in which a natural attenuation process had taken place because of mixing with surrounding carbonate-rich materials. An ecotoxicological survey identified the low toxicity levels of the stabilised samples.Conclusions
The applied bioassay is a good tool for screening metal(loid) contamination in areas affected by mining activities, since it provides information on both natural and simulated attenuation processes. The mixing of sediments with limestone filler could be applied to the remediation of zones affected by mining activities, because the toxicological effect on the tested organisms in the stabilised sediments was reduced significantly and the metal(loid) content was diminished. 相似文献11.
Distribution of total mercury in coastal sediments from Jade Bay and its catchment, Lower Saxony, Germany 总被引：1，自引：0，他引：1
Purpose
Sediment cores provide a reliable record of mercury (Hg) contamination and can be used to study long-term Hg pollution and relevant environmental change. In the last hundred years, there were several events which may have contributed to the accumulation of Hg in Jade Bay and its catchment. This work was undertaken to assess the record in total Hg (THg) content in sediments of cores from Jade Bay and its catchment.Materials and methods
A 5-m sediment core from Jade Bay, Lower Saxonian Wadden Sea, southern North Sea and a 12-m core from its catchment area (Wangerland, coastal zone of the Jade Bay) were used to study Hg contents in sediments. Total Hg, grain size distribution, aluminium (Al) and total organic carbon (TOC) were analysed on subsamples of both sediment cores. Total Hg was determined by oxygen combustion-gold amalgamation using DMA-80.Results and discussion
As THg contents of the Jade Bay core were positively correlated to the sum of TOC and Al contents (r 2?=?0.86, p?<?0.001), the Hg data were interpreted using a regional normalisation function with the sum of Al and TOC as the normalisation parameters. Total Hg contents of the Wangerland core were correlated better to Al contents (r 2?=?0.70, p?<?0.001) than to the sum of TOC and Al contents (r 2?=?0.63, p?<?0.05). Therefore, Hg contents in sediments of the Wangerland core were normalised to Al contents. Comparison between enrichment factors and the background range of the sediment cores suggested that Jade Bay was contaminated about 50 years ago, and that Wangerland, or the catchment area of Jade Bay, was contaminated about 300 years ago, if no diagenetic remobilization occurred.Conclusions
Total Hg contents of both cores were low and of no concern to the aquatic environment of Jade Bay. The Hg record was in good agreement with the history of industrial development in the region; thus, Hg deposition could have occurred through atmospheric input, ammunition residues of the Second World War and volcanic emanations, as well as through diagenetic remobilization. 相似文献12.
Steffen Keiter Sabrina Peddinghaus Ute Feiler Britta von der Goltz Christoph Hafner Nga Yu Ho Sepand Rastegar Jens C. Otte Richard Ottermanns Georg Reifferscheid Uwe Strähle Thomas Braunbeck Monika Hammers-Wirtz Henner Hollert 《Journal of Soils and Sediments》2010,10(4):714-717
Introduction
The European Water Framework Directive aims to achieve a good ecological and chemical status in surface water of European rivers by the year 2015. Since sediments and particulate matter act as secondary sources for pollutants, applied sediment toxicology is perceived to play a major role for obtaining new knowledge that can contribute to successful attainment of the goal. However, the existing bioassays for sediment toxicity analyses do not provide sufficient data concerning bioavailability of environmental pollutants. In this regard, there is an urgent need to combine sediment contact assays with gene expression analysis to investigate mechanism-specific sediment toxicity.Purpose
The aim of the novel joint research project is to develop a eukaryotic test system, which can be used to investigate the ecotoxicological effects of contaminated sediments on gene expression level (DNA-array and RT-PCR). Current ecotoxicological research customarily involves a battery of bioassays to cover different toxicological endpoints (e.g., teratogenicity, genotoxicity, mutagenicity, Ah-receptor-mediated toxicity, neurotoxicity). In contrast, methods that detect alterations in gene expression offer deeper insight by elucidating how chemical exposure and/or environmental challenge affect multiple metabolic pathways leading to these particular kinds of toxic response. Gene expression profiles reflect the way cells and organisms adapt or respond to a changing environment.Conclusion
The present project aspires to increase the fundamental molecular and physiological knowledge concerning the mode of action of environmental toxicants in zebrafish (Danio rerio). By working with partners from the academic and research institutions as well as from industry and waterway regulations, the success of this basic research-driven joint project in terms of development and implementation of novel sediment toxicity methods will be realized. 相似文献13.
Mauricio Montaño Lucien Hoffmann Albertinka Jacoba Murk Arno Christian Gutleb 《Journal of Soils and Sediments》2014,14(6):1200-1212
Purpose
Bioassays have become an alternative for sediment risk profiling, including potential compliance with sediment quality criteria (SQC). In vitro functional bioassays have evolved through standardization and validation towards a confident toxicological hazard estimate of sediments. Sample preparation is a key aspect for the improvement of bioassays. It is a standard practice to use a high single-stock concentration of extracts to further dilute test concentrations from and carry out the analysis. This study was carried out to demonstrate that high a contaminant load in a sediment extract (>20 g sediment equivalents (SEQ) ml?1) oversaturates solubility in carrier solvents and overloads the clean-up columns, potentially resulting in an under- or overestimation of the quantified dioxin-like toxic potency.Materials and methods
Cleaned nonpolar sediment extracts were prepared from samples collected from various locations in Luxembourg. The influence on the quantified toxic potency of the initial stock concentration, sonication assisted dissolution and exposure period in an in vitro bioassay for dioxin-like toxic potency (Bio-TEQ) was evaluated, as well as its impact on the sediment risk characterization according to SQC.Results and discussion
Stock sonication before serial dilution strongly reduced the standard variation of the outcomes. Higher initial stock concentrations (>20 g SEQ ml?1 for contaminated sediments) produced significantly lower Bio-TEQs g SEQ?1 compared to those obtained with initial stock concentrations of 2 g SEQ ml?1, probably due to solvent oversaturation. An initial stock concentration of 2 g SEQ ml?1 is low enough to prevent mis-estimation, but 20 or even 200 g SEQ ml?1 might be used when quantification of Bio-TEQ is required. The overload of extract on clean-up columns caused an overestimation of the dioxin-like potency probably due to PAH-induced false-positive responses.Conclusions
Higher contaminant load in the initial extracts from sediments affects the reliability of in vitro Bio-TEQ sediment quantification. Advice is given on how to avoid underestimation because of extract oversaturation, avoid overestimation because of overload of clean-up columns and reduce variability by applying sonication in standard testing protocols for risk characterization and quantification of the sample’s toxic potency. Taking into account the new aspects revealed in this study, in addition to important issues for quality control that are already included, the in vitro bioassays based on Bio-TEQs can be applied in a comprehensive monitoring program to determine whether sediments comply with health and safety standards for humans and the environment. 相似文献14.
Hanno Zielke Thomas-Benjamin Seiler Sabine Niebergall Erik Leist Markus Brinkmann Denise Spira Georg Streck Werner Brack Ute Feiler Thomas Braunbeck Henner Hollert 《Journal of Soils and Sediments》2011,11(2):352-363
Purpose
Traditionally, methods for sediment extractions are characterised using chemical analyses. However, in order to evaluate sediment extracts with regard to biological effects and, thus, bioaccessibility, extraction methods have to be compared to effect data obtained from experiments with in situ exposure scenarios, i.e., sediment contact tests. This study compares four extraction methods and sediment contact test data from a previous project with respect to predictive power in the fish embryo test with zebrafish (Danio rerio).Materials and methods
A natural and an artificial sediment spiked with a mixture of six organic pollutants (2,4-dinitrophenol, diuron, fluoranthene, nonylphenol, parathion and pentachlorophenol) were extracted using (a) membrane dialysis extraction (MDE), (b) a Soxhlet procedure, (c) hydroxypropyl-??-cyclodextrin (HPCD) or (d) Tenax®-TA. Whereas the former two are regarded being exhaustive with respect to non-covalently bound contaminants, the latter two are considered to predict bioaccessibility. Resulting extracts were tested in the fish embryo assay with D. rerio for embryotoxic and teratogenic potential.Results and discussion
Mortalities caused by organic extracts from Soxhlet extraction and MDE were high. However, HPCD extracts turned out to be at least as effective as extracts obtained with these two methods. One possible reason might be short ageing time of the spiked sediments. Only Tenax®-TA extracts gave results comparable to the sediment contact assay for natural sediment, but revealed low reproducibility. Significant differences between natural and artificial sediment were found for extracts obtained with techniques using native (i.e., non-freeze-dried) sediments, i.e., HPCD and Tenax®-TA. In contrast, MDE and Soxhlet extracts used freeze-dried sediment and did not differentiate between natural and artificial sediment. Therefore, freeze-drying has likely altered and equalised sediment properties that influence accessibility, such as composition of bacterial communities and organic matter quality.Conclusions
Four extraction methods were successfully characterised with respect to their stringency and predictiveness for bioaccessibility. MDE was confirmed as an alternative to Soxhlet extraction. High mortalities induced by HPCD extracts underline the need to include ageing into consideration when assessing sediments. Although Tenax®-TA may basically be used to predict bioaccessibility in the fish embryo test, the high variability observed warrants further investigation of the relation between effect and extractability. Apparently, freeze-drying can severely affect sediment properties, potentially eliminating individual properties of natural sediments. 相似文献15.
Purpose
Knowledge of archaeal communities is essential for understanding of the mechanism of carbon and nitrogen cycle in the mangrove sediment ecosystem. Presently, little is known about archaeal communities in the Dongzhaigang mangrove sediments. This study aimed to characterize the archaeal communities in sediments of different mangrove stands and to find out the correlations between archaeal communities and the environmental factors of sediments.Materials and methods
Sediment samples were collected from the Dongzhaigang mangrove forest for analysis of soil properties and archaeal communities, by national standard methods and Illumina Miseq archaeal 16S ribosomal RNA (rRNA) gene sequencing, respectively.Results and discussion
The archaeal community in the Dongzhaigang mangrove forest was constituted by some phyla from “TACK” and “DPANN” supergroups, and dominated by Euryarchaeota. Among sediments of the four mangroves in Dongzhaigang, principal coordinates analysis (PCoA) scatter plot showed a trend of difference in the archaeal community structure in the Bruguiera gymnoihiza and Kandelia candel stands from that in the Laguncularia racemosa and Sonneratia apetala stands. The abundance of the order Methanosarcinales was the highest in the sediments of K. candel mangroves, whereas the order of Methanobacteriales dominated in B. gymnoihiza sediments. The highest richness and diversity values of Archaea occurred in K. candel sediments, while the lowest in B. gymnoihiza. Pearson correlation showed the significant relationships between sediment properties and some dominant genera, with a positive and significant correlation between sediment properties and genus Methanobacterium, coinciding with the maximum values of sediment properties and abundance of Methanobacterium in the sediment of B. gymnoihiza. Such results indicated that the difference of archaeal community structure among mangrove sediments may be caused by the different sediment characteristics. Methanogenic communities in the Dongzhaigang mangrove forest sediments were, at the order level, constituted by Methanobacteriales, Methanomicrobiales, Methanosarcinales, and Methanomassiliicoccales.Conclusions
The investigation indicated that the Dongzhaigang mangrove sediment ecosystems support diverse archaeal communities and methanogenic communities, and that there was a general trend of difference in the archaeal community structure in the B. gymnoihiza and K. candel mangrove sediments from that in the L. racemosa and S. apetala sediments. Such difference may be caused by the difference in sediment characteristics.16.
Sansfica M. Young Hiroaki Ishiga Barry P. Roser Amarasooriya Pitawala 《Journal of Soils and Sediments》2014,14(1):204-217
Purpose
The geochemical compositions of sediments from three sectors in Trincomalee Bay (Koddiyar Bay, Thambalagam Bay and the Inner Harbour) in Sri Lanka were examined to determine fluvial and marine contributions and the effects of sorting and heavy mineral concentration. The present environmental status of the bay was also assessed.Materials and methods
Forty-nine sediment samples were collected from Trincomalee Bay and analysed by X-ray fluorescence, yielding data for the major elements and 17 trace elements. Mean grain size and sorting were also measured. Data were compared with the compositions of sediments from the lower Mahaweli River, which supplies most of the clastic detritus to Trincomalee Bay.Results and discussion
Sediments in the three sectors differ significantly in chemical composition, according to position relative to the Mahaweli River delta source, depositional environment, heavy mineral concentration and marine influences. According to accepted sediment quality guidelines, some As contamination may have occurred in the Inner Harbour and Thambalagam Bay and Cr contamination in all three sectors.Conclusions
Proximal Koddiyar Bay sediments compare closely with Mahaweli River bedload. Although the clastic component in the more distal Thambalagam Bay and the Inner Harbour is also derived from the Mahaweli River, compositions are modified significantly by marine contributions. High concentrations of elements including Ti, Zr, Ce, Nb and Y in NW Koddiyar Bay are consistent with heavy mineral concentration by winnowing in high-energy zones. Some decoupling of Fe–Ti- and Zr-bearing heavy mineral assemblages may occur within the bay. Al-normalized metal enrichment factors and contour maps show that apparent contamination by As and Cr is spurious and is caused by locally high background levels from Mahaweli River detritus. This illustrates the importance of establishing local background levels of elements during environmental studies. 相似文献17.
Annie Melinda Paz-Alberto Arnel B. Celestino Gilbert C. Sigua 《Journal of Soils and Sediments》2014,14(1):251-258
Purpose
Coal-fuelled power plants can discharge hazardous materials, particularly heavy metals such as lead (Pb). An alternative way of reducing Pb concentration from contaminated sediments is through phytoremediation. Presently, there are few research findings on the phytoremediation potential of mangroves on metals like Pb. The study was conducted to survey and identify mangroves that thrive near the coal-fired power plant and to assess the phytoremediation potential of mangroves on Pb in sediment.Materials and methods
The study sites were located in the mangrove ecosystems of Sitio Oyon and Sitio Asinan in Masinloc, Zambales, Philippines. The first stage of our study was to survey and identify the mangrove species. The second stage was to assess the levels of Pb in the sediments, water, and tissues of mangrove trees. The diversity assessment of the mangrove species was done through the use of 10?×?12 m quadrat technique. Water and sediment samples from each mangrove ecosystem were collected using composite sampling methods.Results and discussion
Three mangrove species were identified in the study sites: Avicennia marina, Rhizophora stylosa, and Sonneratia alba. The order of importance of the mangrove trees in the two sampling locations, based on an importance value index (IVI), were as follows: SA (IVI?=?171.20)?>?AM (77.79)?>?RS (51.01). The total uptake of Pb from sediments near the power plants varied significantly (p?≤?0.001) among the three mangrove species. S. alba had the highest Pb uptake of 48.4 kg ha?1 followed by A. marina (23.1 kg ha?1), and R. stylosa (2.4 kg ha?1). These three mangrove species have the potential to phytoremediate Pb in the sediment.Conclusions
The three mangrove species present in the coastal ecosystem near the electric power plant—A. marina, R. stylosa, and S. alba—were potential phytoremediators of sediment Pb. The present study indicated that the mangroves possess beneficial characteristics that remove Pb from contaminated sediments in areas directly affected by coal-fired power plants, and thus have potential phytoremediation properties. 相似文献18.
Ana Romero-Freire Manuel Sierra-Aragón Irene Ortiz-Bernad Francisco J. Martín-Peinado 《Journal of Soils and Sediments》2014,14(5):968-979
Purpose
The present work evaluates the influence of different soil properties and constituents on As solubility in laboratory-contaminated soils, with the aim of assessing the toxicity of this element from the use of bioassays to evaluate the soil leachate toxicity and thereby propose soil guideline values for studies of environmental risk assessment in soil contamination.Materials and methods
Seven soils with contrasting properties were artificially contaminated in laboratory with increasing concentrations of As. Samples were incubated for 4 weeks, and afterwards, soil solution (1:1) was obtained after shaking for 24 h. The soil leachate toxicity was assessed with two commonly used bioassays (seed germination test with Lactuca sativa and Microtox ® test with Vibrio fischeri).Results and discussion
The relationship between soluble As and soil properties indicated that iron oxides and organic matter content were the variables most closely related to the reduction of the As solubility, while pH and CaCO3 increased As solubility in the soil solutions. Toxicity bioassays showed significant differences between soils depending on their properties, with a reduction of the toxicity in the iron-rich soil (no observed effect concentration (NOEC)?=?150 mg kg?1) and a significant increase in the highly carbonate samples (NOEC between 15 and 25 mg kg?1).Conclusions
Soil guideline values for regulatory purposes usually set a single value for large areas (regions or countries) which can produce over- or underestimation of efforts in soil remediation actions. These values should consider different levels according to the main soil properties controlling arsenic mobility and the soil leachate toxicity. 相似文献19.
Guanghuan Cheng Liuchenghang Zhu Mingyang Sun Jingyou Deng Huanyu Chen Xinhua Xu Liping Lou Yingxu Chen 《Journal of Soils and Sediments》2014,14(2):344-352
Purpose
There is a strong affinity between organic compounds and black carbon (BC) in sediments, but the release of adsorbed organic compounds from BC may vary with the duration of contaminant–sediment contact (i.e., aging). The objective of this paper was to evaluate the effect of the application of rice straw carbon (RC) on the control of hydrophobic ionizable organic compounds (HIOCs) pollution and investigate whether aging affects the release of adsorbed pentachlorophenol (PCP) in RC-amended sediment.Materials and methods
Two experiments were conducted in this study: Tenax-mediated desorption kinetics experiment and PCP’s distribution experiment over aging time. The Tenax-mediated desorption kinetics data were fit with a modified two-domain model. PCP’s distribution pools in sediment involves water soluble (F 1), 48 h desorption (F 2), 432 h desorption minus 48 h desorption (F 3), strongly complexed (F 4), and nonextractable fractions (F 5).Results and discussion
A good fit of the desorption kinetics data was obtained with the modified two-domain model, and R 2 ranged from 0.979 to 0.999. The presence of RC in the sediment reduced the rapid and slow desorption fractions (F rap and F slow) as well as the rapid and slow rates of desorption of PCP (k rap and k slow) from the sediment, and the RC also increased the desorption-resistant fraction (F r ). F rap and F slow both increased, while F r decreased after aging. The PCP content of F 1, F 2, and F 3 increased but decreased in F 4 and F 5 with contact time. Furthermore, the segregation of PCP varied less with aging time in sediments with 2.0 % RC than in sediments with 0.5 % RC.Conclusions
RC played a dominant role in hindering PCP mass transfer and reducing PCP availability in sediments. After the RC-amended sediment was aged for 98 days, the PCP was released more easily and became more readily available, which was attributed primarily to the RC–sediment aging rather than of the PCP–sediment aging. Furthermore, 0.5 % RC is not sufficient to control PCP release from sediments, and 2.0 % RC is needed to fix PCP in sediments over long periods of time. 相似文献20.
Aili Wang 《Journal of Soils and Sediments》2014,14(1):243-250