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1.
Doyoon Kim Jeeeun Min Ji-Young Yoo Jae-Woo Park 《Journal of Soils and Sediments》2014,14(10):1766-1773
Purpose
Activated carbons (ACs) were applied to evaluate the effects of surface oxidation on bioavailability and bioaccumulation of cadmium (Cd) and copper (Cu) in freshwater sediment along with Eisenia fetida biomass change.Materials and methods
A modified sequential extraction procedure was conducted to measure the changes in bioavailable fractions of heavy metals 6 weeks after the addition of nitric acid-oxidized AC. Bioaccumulation of heavy metals in E. fetida was analyzed after 2 weeks of exposure to AC-amended contaminated sediments. Changes in biomass of earthworms caused by AC amendments were observed over 2 weeks of exposure to clean sand.Results and discussion
Surface oxidation of AC caused little impact on AC surface properties except for oxygen contents leading to enhanced sorption capacity for heavy metals. Bioavailable fractions of the heavy metals increased after 6 weeks, and less was bioavailable with various ACs than without AC. The earthworms were exposed to the sediments mixed with ACs for 6 weeks. After 2 weeks of exposure, bioaccumulation of Cd and Cu decreased drastically. More than 76 % of Cd and 80 % of Cu reductions were observed with each type and dose of AC. Weight loss of E. fetida incubated in clean sand for 13 days after AC amendments was observed, but was not affected by surface oxidation.Conclusions
Inhibited growth of E. fetida due to AC could be responsible for the reduced bioaccumulation of Cd and Cu in the earthworms as AC inhibited the movement of earthworms, leading to less bioturbation and decreased consumption of nutrients. 相似文献2.
Dileep Palakkeel Veetil Guy Mercier Jean-Francois Blais Myriam Chartier Lan Huong Tran 《Journal of Soils and Sediments》2013,13(8):1502-1514
Purpose
This study addresses the feasibility of a flotation technique, using a lab-scale flotation cell, to simultaneously remove both metals and polyaromatic hydrocarbons (PAHs) from fine sediment fractions (<250 μm) that are potentially contaminated with copper (Cu).Materials and methods
A multiple flotation process with three consecutive flotation stages was performed on three sediments (13S, 14B, and 24A) with different particle size distributions, Cu and PAH concentrations, and organic matter contents.Results and discussion
Flotations performed under selected conditions allowed for significant removal of both Cu (61–70 %) and PAHs (75–83 %) with acceptable froth recoveries of approximately 23–29 %. Removal rates for arsenic, lead, and zinc were 48–61, 40–48, and 32–36 %, respectively. Flotation selectivity of Cu was greatly influenced by the contents of fine particles and organic matter of the sediments. The maximum flotation selectivity was obtained for the 53–125-μm size fraction. The high flotation selectivity of Cu (2.5–3.2) and PAHs (3.0–3.6) demonstrated the feasibility of flotation to treat soils or sediments containing both organic and inorganic pollutants.Conclusions
Overall, the flotation results showed a high selectivity for both Cu and PAHs and demonstrated the feasibility of flotation to treat media contaminated with organic and inorganic contaminants. 相似文献3.
Lei Wang Hongwen Sun Guohua Zhang Shujuan Sun Xinmei Fu 《Journal of Soils and Sediments》2013,13(2):450-459
Purpose
The aim of this study was to assess the applicability of ionic liquids (ILs) in the extraction of organic contaminants from sediments and in passive sampling as a receiving phase material.Materials and methods
Solutions of two water-soluble ionic liquids (WSILs)—1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIm]BF4) and N-butyl-3-methyl pyridinium tetrafluoroborate ([BMPy]BF4)—were used for the extraction of endocrine-disrupting chemicals (EDCs), including bisphenol A (BPA), 17β-estradiol (E2), and nonylphenol (NP), from different sediments. Furthermore, a hydrophobic IL (1-hexadecyl-3-methyl imidazolium hexafluorophosphate) was filled in a polyethylene (PE) membrane tubing to build an IL-PE passive sampler for sediment pore water. Uptake kinetics were studied by exposing samplers to sediments artificially contaminated by EDCs and identified by exposing samplers to field-contaminated sediments.Results and discussion
EDCs were efficiently extracted by WSIL solutions from the two artificially contaminated sediments, with maximum extraction efficiencies of 84.2–104.6 % by the [BMIm]BF4 solution and 74.9–103.7 % by the [BMPy]BF4 solution. However, WSIL solutions are not suitable for EDC extraction from sediment with very low organic carbon contents. EDCs in sediment pore water can be efficiently taken up by the IL-PE sampler, with uptake rate constants of 2.08?×?10?2?l?g?1?day?1 (BPA), 5.74?×?10?2?l?g?1?day?1 (E2), and 2.10 l?g?1?day?1(NP).Conclusion
BPA, E2, and NP can be extracted efficiently by IL water solution from most of the artificially and field-contaminated sediments used in this study. The IL ([HDMIm]PF6)-PE passive sampler can be used to monitor EDCs in the pore water of sediments. A good match between the calculated and measured concentrations of BPA and E2 in pore water of field-contaminated sediments was observed. 相似文献4.
Guo-Liang Shi Ying-Ze Tian Chang-Sheng Guo Yin-Chang Feng Jian Xu Yuan Zhang 《Journal of Soils and Sediments》2012,12(7):1154-1163
Purpose
Understanding the fate and behavior of polycyclic aromatic hydrocarbon (PAH) sources in aquatic systems is important for the efficiency of control policies. In this work, a new approach??organic carbon-normalized sediment?Cpore water partition coefficients of PAH source contributions (logK??Osource)??was developed to study the sediment?Cpore water partition of PAH source contributions. The focus of this study was the Yellow River, which is the second largest river in China and one of the largest rivers in the world.Materials and methods
Sixteen priority US Environmental Protection Agency PAHs were analyzed in 14 surface sediments and 11 pore water samples. Principal component analysis?Cmultiple linear regression (PCA-MLR) and Unmix models were employed to estimate the source contributions of PAHs in sediments and pore water samples. Finally, logK??Osource values were calculated according to the modeled source contributions of PAHs.Results and discussion
??PAHs (sum of the 16 PAH concentrations) in 14 sediment samples and 11 pore water samples from the Yellow River were 1,415?±?726?ng?g?1 dry weight (dw) and 123?±?57.4???g?l?1, respectively. The source apportionment results indicate the following: (1) for sediment samples, the contributions to ??PAHs from vehicular emissions, coal combustion, and petrogenic sources were 41.07?C61.05, 38.83?C45.56, and 11.18?C14.92?%, respectively, and (2) for pore water samples, vehicular emissions were the most significant contributor (45.51?C69.39?%), followed by petrogenic sources (29.80?C34.22?%) and coal combustion (7.35?C21.59?%). Coal combustion had the highest logK??Osource values (4.15?C4.26) among the three categories, followed by vehicular emissions (3.51?C3.57) and petrogenic sources (3.30?C3.43).Conclusions
The possible categories of PAH sources identified by hierarchical cluster analysis, PCA-MLR, and Unmix models were consistent, indicating that vehicular emissions, coal combustion, and petrogenic sources were three important categories. The logK??Osource values indicate that contributions from coal combustion had a higher partition for the sediment phase compared with the other two source categories. 相似文献5.
Glaucia Pantano Mariele Barboni Campanha Altair Benedito Moreira Márcia Cristina Bisinoti 《Journal of Soils and Sediments》2014,14(2):377-384
Purpose
The purpose of this paper is to study the interactions of sedimentary humic substances (SHS) from a sugarcane cultivation area with Cu(II) and Cr(III) and to evaluate the occurrence of these metals in the pore water and SHS.Materials and methods
For this study, the northwestern region of the State of São Paulo, Brazil, which is considered the region with the highest production of sugar cane in the state, was selected. Samples of sediment were collected from four sampling sites in the Preto, Turvo, and Grande rivers. The SHS and pore water were extracted from the sediment using the method suggested by the International Humic Substances Society and centrifugation, respectively. The complexing capacity (CC) of the SHS for Cu(II) and Cr(III) was determined by individually titrating these metals with an ultrafiltration system using tangential flow. The total concentrations of Cr and Cu were determined for the pore water, sediments, and humic substances with graphite furnace atomic absorption spectrometry and Zeeman background correction after an acid digestion, according to the methods described in US EPA Method 3050B.Results and discussion
The SHS from a site in the Turvo River, which is typically cultivated with sugarcane, possessed the highest concentration of Cu bound to SHS (25.0%), the largest CC (0.63 mmol Cu g?1 HS) and the highest concentration of this metal in the pore water (1.38 mg Cu Kg?1 sed.). For Cr, the SHS collected from a location on the Preto River dam had the largest CC (0.90 mmol Cr g?1 HS) and the lowest Cr content in the pore water (0.29 mg Cr Kg?1 sed.), indicating that there was an inverse relationship between the CC and the concentration of metal available in the pore water.Conclusions
Sedimentary humic substances might be one of the regulatory factors controlling the availability of Cu and Cr in the sediments found in a typical region that has been planted with sugarcane. Distinct behaviors were observed between the two elements investigated; higher CC and a larger fraction of Cu(II) were found in the pore water of samples originating from sugarcane crops. The opposite behavior was observed for the Cr(III) species. 相似文献6.
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7.
Maha Chalhoub Laurence Amalric Solène Touzé Pierre Gallé Pascal E. Reiller Noëlle Doucet Blandine Clozel Philippe Bataillard 《Journal of Soils and Sediments》2013,13(7):1284-1300
Purpose
Remobilization of polychlorobiphenyl (PCB)-contaminated sediments by anthropogenic activities (e.g. dredging) or natural flow conditions could lead to the release of PCBs into the water column and consequently increase the availability of PCBs to benthic organisms. The fate of the released PCBs following such events is not well understood and such knowledge is necessary for the management of contaminated sediments. The objective of this study was to understand the processes that control the fate of PCBs following remobilization of field-aged contaminated sediments.Materials and methods
Sediments contaminated with PCBs collected from Lake Bourget (Savoie, France) were resuspended in a column experiment. The relationships between physical–chemical parameters—i.e. suspended particulate matter, pH, inorganic and organic carbon content, redox-sensitive species and the concentrations of dissolved PCBs both in the water column and in the interstitial water of the sediment—were investigated so as to determine the key processes controlling PCB fate.Results and discussion
Following the simulated resuspension event (SRE), dissolved PCBs were found in much higher concentrations in the water column than under stationary conditions. Desorption of PCBs from the sediment depended on the degree of the hydrophobicity of the PCBs and the initial PCB content in the sediment. Principal component analysis showed that the variations in the concentrations of released PCBs over time and space closely followed those of suspended particulate matter (SPM) and not those of redox conditions. The partitioning behaviour of PCBs on SPM showed that equilibrium state was not attained within 40 days following the SRE. A particle size fractionation study, before and after remobilization of the sediment, showed the presence of PCBs in every fraction of the sediment, but with higher amounts in large particles with high organic matter content and in the finest fractions. Remobilization of contaminated sediment did not affect this distribution profoundly but a significant enrichment in PCBs of the clay-sized fraction was observed in the re-settled sediment.Conclusions
Sediment resuspension induced non-equilibrium conditions in the water column for more than 5 weeks and led to the enrichment with PCBs of the newly formed surface bed sediment. This enrichment was due to the preferential re-sorption of PCBs on clay-sized particles during the SRE and to the physical segregation and accumulation of the less dense particles at the surface of the sediment column; such particles thought to be the principal carriers of contaminants. These changes concerned <0.05 % of the total PCB content. 相似文献8.
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9.
Background, aim, and scope
The Mecklenburg Bight (Western Baltic Sea) near Luebeck, Germany was historically used to dump industrial waste at sea and, thus, sediments in some regions are highly polluted at present. While earlier studies identified hot spots of chemical pollution, little is known about biological activities and impacts on exposed marine organisms. This study aimed to assess the pollution in the Mecklenburg Bight to determine the degree of contamination with sediment-bound polycyclic aromatic hydrocarbons (PAHs) as well as biological activities.Materials and methods
Sediment cores with a depth of 30 cm were sampled at a dumping site and at a reference site, sliced in distinct layers, freeze-dried, and processed using the accelerated solvent extraction method. Sediment was characterized measuring total organic carbon (TOC) and soot contents. Concentrations of the 16 EPA-PAHs were determined with chemical analysis (gas chromatography–mass spectroscopy) in each sediment slice and referred to the determined TOC content. Further on, in vitro biotests were applied to determine toxic effects of contaminants in the sediment. The acute neutral red retention assay indicated no specific cytotoxic effects. Arylhydrocarbon receptor (AhR)-mediated activities were measured using the mechanism-specific 7-ethoxyresorufin-O-deethylase induction assay. Both biotests were performed with rainbow trout (Oncorhynchus mykiss) liver cells (RTL-W1). Analyzed compound concentrations and biological activities were given in toxicological equivalent concentrations (chem- and bio-TEQs) to determine shares of analyzed EPA-PAHs to the overall activity.Results
TOC and soot contents indicated a significant alteration through the sediment core at the dumping site. EPA-PAH concentrations were referred to TOC and indicated elevated concentrations at the dumping site. Maximum PAH concentrations (14 to 16 cm depth; 5.44 µg/g TOC) were 300-fold increased at the dumping site, compared to the reference site (4 to 6 cm depth; 0.017 µg/g TOC). Cytotoxicity as determined in the neutral red retention assay was elevated in some layers at the dumping site (maximum in 4 to 6 cm depth; NR50?=?14 mg/ml), but not correlated with TOC or soot contents. Ah receptor agonist activities were clearly elevated in highly PAH-loaded layers at both sites. At the dumping site, maximum activities were determined reflected by a bio-TEQ of 223,000 pg/g (19 to 22 cm), in contrast to a bio-TEQ of 41,000 pg/g (6 to 8 cm) at the reference site. Further on, shares of EPA-PAHs to the overall activity were determined and contributed >40% at the dumping site and between 4% and 17% at the reference site. Chem-TEQs were found to exceed bio-TEQs in a depth of 11 to 22 cm, indicating the presence of Ah receptor antagonistic or inhibitive compounds.Discussion
Sediments from the dumping site were determined to be highly contaminated and caused toxic effects in depths that are known to be influenced by dumping activities. In contrast, the reference sediment indicated only near to surface layers to be minor contaminated. In comparison with highly polluted sediments from other marine sites, the contamination of the dumping site could be ranked as elevated. Chem-TEQs exceeding bio-TEQs in a depth of 11 to 22 cm seem to be caused by AhR antagonistic compounds in the dumped material. Furthermore, particle-bound PAH concentrations assessed in this study were discussed against freely dissolved concentrations in interstitial water, as determined in a different study with the same sediment core.Conclusions
Sediments in the inner Mecklenburg Bight could be shown to be highly contaminated, at least with PAHs, causing articulate increased Ah receptor-mediated activities. Marine organisms may be exposed to these contaminants, in particular when inhabiting the sediment.Recommendations and perspectives
Further research activities should extend the range of chemically analyzed pollutants and applied biotests and endpoints. Monitoring should close the gap between analytical methods in the laboratory and the field to determine possible impacts on organisms at site. 相似文献10.
Gladys A. Liehr Susanne Heise Wolfgang Ahlf Kristen Offermann Gesine Witt 《Journal of Soils and Sediments》2013,13(7):1270-1283
Purpose
During the late 1950s and early 1960s, industrial waste material highly enriched with various contaminants (e.g., heavy metals, polycyclic aromatic hydrocarbons (PAHs)) was dumped in the inner Bay of Mecklenburg, western Baltic Sea. Between 2002 and 2004, a research program was initiated using chemical analysis in combination with bioanalytical techniques to assess the extent and variability in contamination at this dump site (DS). The data were compared to a reference area (RS) with similar environmental conditions, which is representative of the western Baltic Sea.Materials and methods
Twelve PAHs were investigated to assess their ecological hazard, as they were identified as major pollutants in the dumped material. In addition to analyzing the actual PAH contamination status in the sediments, PAHs measured in the soft tissue of Arctica islandica were also used as an indicator of contaminant bioaccumulation. A biotest battery was applied to determine the toxic effects of contaminants in the sediment.Results and discussion
Significantly elevated PAH concentrations (sum of 12 PAHs) of ～3,000 ng g?1 dw and higher bioaccumulation factors (BAFs) were determined in the soft body tissue of A. islandica collected at DS (t test, p?=?0.025). The results also showed that the sediment PAH contamination was significantly higher at DS (1,952–5,466 ng g?1 dw) than at RS (1,384–2,315 ng g?1 dw). The results revealed a major heterogeneity in the PAH concentration at DS due to an attempt to cover the toxic material with clean clay. This resulted in a more heterogeneous distribution of the dump material rather than covering it up completely. However, not all relevant contaminants were included in this study, not only because it is too costly to determine them all but also because unidentified contaminants present at concentrations below the limit of detection cannot be measured. Bioassays were used to fill this gap in the hazard assessment in a cost-effective way by investigating the possible effects of sediment contamination on benthic organisms. The results showed a high variability and magnitude of growth and luminescence inhibition. Bacterial contact tests with marine organisms showed a high toxicity response (>80 % inhibition) from DS sediments. In contrast, the luminescent bacteria test (Vibrio fischeri) showed equivalent effects of sediments from both DS and RS.Conclusions
The spatial distribution of toxicity in DS, the bioaccumulation in mussels and the analytical evidence of PAH pollution clearly show that the dumped material still represents a potential risk even after 60 years. 相似文献11.
Takehiko Fukushima Seigo Watanabe Koichi Kamiya Noriatsu Ozaki 《Journal of Soils and Sediments》2012,12(10):1530-1540
Purpose
The purpose of this study was to elucidate historical trends, spatial variations, and the sources of polycyclic aromatic hydrocarbons (PAHs) pollution in several Japanese lakes.Materials and methods
The vertical distributions of PAHs in the core samples of sediments taken at several points in lakes Kasumigaura, Suwa, Kizaki, and Shinji were determined using a gas chromatograph equipped with a mass selective detector and combined with chronological information and the physical/elemental properties of the sediment.Results and discussion
Seventeen related compounds (congeners) typically had concentration peaks at sediment depths corresponding to the 1960s to 1970s. In Lake Shinji and one bay of Lake Kasumigaura, there was a tendency for PAH concentrations to increase downstream; in contrast, another bay of Lake Kasumigaura showed the reverse trend. During big flood events, the fluxes of PAHs increased due to large inputs of particulate matter, although PAH concentrations were reduced. For the four study lakes and other similar lakes, PAH concentrations of surface sediments were approximately proportional to population densities in the respective watersheds, while the total input of PAHs to the lakes were correlated with their population and watershed area. The source apportionment analysis using isomer ratios for the congener profiles indicated that the principal sources of the PAHs in the lake sediments were gasoline and/or diesel engine exhausts and biomass burning.Conclusions
The observed concentration peaks showed a deterioration of the chemical quality of atmospheric conditions around 1960?C1970 and a recent tendency for their amelioration. Between-lake differences suggest that the influence of human activity in the watersheds influences sediment PAH concentrations. The PAH sources were identified to be of pyrogenic origin. 相似文献12.
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13.
Anaïs Coulon Amelène El-Mufleh Patrice Cannavo Laure Vidal-Beaudet Béatrice Béchet Sylvain Charpentier 《Journal of Soils and Sediments》2013,13(3):508-518
Purpose
In stormwater infiltration basins, sediments accumulate at the soil surface and cause a gradual filling up of soil pores. These sediments are composed of a mixture of natural and anthropogenic (as oil products) organic matters (OMs). The degradation kinetics of these sediment OMs and their biological stability has been neglected. This study aimed to characterize sediments OMs to assess their evolution and their capacity to degrade.Materials and methods
To characterize OMs from the sediment layer, we measured at several places in the infiltration basin, total OM and carbon (C) contents, C distribution and biochemical fractions of the OM in the different size fractions, the sediment’s C mineralization potential, soil microbial biomass, and organic pollutants (polycyclic aromatic hydrocarbons (PAHs)) in the sediment layer.Results and discussion
OM contents were high and varied from 66 to 193 g?kg?1 from the inlet to the outlet of basin. Depending on rainfall intensity and volume, organic particles were deposited at varying distances in the basin by decantation; this was confirmed by analysis of sediment C distribution in the different size fractions. Despite high amounts of OM, organic C had a low biodegradability. Mineralization potentials were low compared to natural soil (i.e., from 0.3 to 1.1 g CO2–C kg?1 total organic carbon). Biochemical fractionation of the organic fractions indicated that they were mainly composed of a soluble fraction, which contributed to reducing OM biodegradability. The activity of the sediment microbial biomass was low. PAH contents seemed to be partly responsible for the high biostability of OMs.Conclusions
There was limited capacity for biodegradation of sediment OMs probably due to inhibitory effects of soluble PAHs and consequently low microbial activity. 相似文献14.
Gerardo Ojeda Joana Patrício Stefania Mattana Abilio J. F. N. Sobral 《Journal of Soils and Sediments》2016,16(10):2482-2491
Purpose
Biochar is a carbon-rich product, able to enhance soil fertility and mitigate CO2 emissions. While biochar effects on agriculture are becoming known, its impact elsewhere, e.g., on estuarine ecosystems, has yet to be assessed. The main aim of the present study was to determine the effect of biochar on sediment–water retention, CO2 emissions from sedimentary organic carbon decomposition, sediment pH and electrical conductivity, in aerobic conditions similar to those observed at low tide.Materials and methods
Sediments from the Mondego Estuary (Portugal) were mixed with pine gasification biochar at different doses (5, 10, 14 %) and immersed in water with different salinity values (15, 25, 30) for 96 h. The influence of biochar on water retention, the residence time of water and CO2 emissions between ?0.75 and ?1.5 MPa, total organic carbon, pH and electrical conductivity (EC) were determined. Carbon chemical composition and polycyclic aromatic hydrocarbon (PAH) concentrations were determined in sediments and biochar. Differences between biochar treatments after immersion in different water salinities were analysed using the Kruskal–Wallis test.Results and discussion
Results showed that biochar was able to (a) increase sediment–water content in terms of quantity and residence time, (b) decrease CO2 emissions, but only with a specific soil–water content and at the highest biochar dose, (c) increase sediment pH at all biochar doses and (d) increase sediment EC at the highest biochar dose. In contrast, the percentage of carbon mineralised was not modified. Biochar carbon was rich in PAHs and less decomposable than sedimentary carbon. The increments observed in sediment pH and EC were unable to change sediment alkaline or saline status according to standard classifications.Conclusions
Our results suggest that the remarkable water adsorption capacity of biochar–sediment mixtures may be considered the main factor in regulating CO2 emission rates from sediments, together with high PAH concentrations, which probably restrain the organic matter decomposition process.15.
Purpose
Suspended particulate sediment (SPS) concentration has a great impact on the sediment to water partitioning coefficients (K p) of hydrophobic organic compounds (HOCs), which is called the particle concentration effect (PCE). However, the mechanisms regarding the PCE are not yet well understood, and there is little direct experimental evidence for these mechanisms. The aim of this study was to investigate the PCE of polycyclic aromatic hydrocarbon (PAH) sorption on sediment by analyzing the freely dissolved concentrations of PAHs.Materials and methods
Sediments were collected from the Yellow River and the Haihe River in China. Pyrene was selected as a model PAH to investigate the sorption of PAH on sediments. In addition to the total dissolved concentration (C TW) of pyrene, the freely dissolved concentration (C FW) measured by polyethylene devices was used to investigate the PCE of pyrene in the presence and absence of phenanthrene and chrysene.Results and discussion
For both the Haihe River and Yellow River sediments, in the presence and absence of other PAHs, the K p value of pyrene with C FW as the equilibrium concentration in the water phase was approximately two times higher than that with C TW as the equilibrium concentration. With either C TW or C FW as the equilibrium concentration in the water phase, the K p value of pyrene decreased with increasing SPS concentration as a power function. In addition, the K p value with C TW as the equilibrium concentration decreased faster than that with C FW. This inferred that, apart from a third phase including dissolved organic carbon (DOC) and colloids, particle–particle, or particle–DOC interactions were important for the PCE. The contribution of the third phase to the PCE for the Haihe River sediment (72.5?±?26.4 %) was greater than the contribution for the Yellow River sediment (48.4?±?16.2 %), which had a larger particle size and lower total organic carbon and black carbon contents.Conclusions
The PCE of PAH sorption onto sediments was attributed to both the third phase and to particle–particle or particle–DOC interactions. The contribution of the third phase to the PCE depended on both the TOC content and the particle size of sediment. As high SPS and DOC concentrations exist in many rivers, their effects on the sorption of HOCs should be considered when conducting bioavailability and ecological risk assessment. 相似文献16.
Peng Liang Cheung-Lung Lam Zhang Chen Hong-Sheng Wang Jian-Bo Shi Sheng-Chun Wu Wen-Xiong Wang Jin Zhang Hailong Wang Ming-Hung Wong 《Journal of Soils and Sediments》2013,13(7):1301-1308
Purpose
The aim of the present study was to investigate the differences of methylmercury (MeHg) formation and distribution between mariculture (aquaculture) sediments (MS) and reference sediments (RS) collected from a site in Hong Kong.Materials and methods
The MS and RS samples were split into four batches, three of which were spiked with HgCl2 aqueous solution to a concentration of 0.8, ,2 and 8 mg k g?1 in sediment samples SP1, SP2, and SP3, respectively, while the rest served as a control batch (referred to as C).Results and discussion
The results showed that the highly Hg-polluted sediment produced greater amounts of MeHg. During the culture period, MeHg concentrations in sediments decreased over time. The decreasing percentage increased in the order of SP3?<?SP2?<?SP1, which might be due to the inhibition of MeHg degradation by high Hg concentrations. The mean value of MeHg concentrations and %MeHg of the total Hg (THg) in MS was significantly lower than those in RS, possibly due to the complexation of Hg with organic ligands, leading to lower Hg bioavailability for methylation bacteria. The distribution coefficient of THg (KdT) was relatively high in MS compared to RS, indicating that the former had a greater number of binding sites for Hg adsorption.Conclusions
Methylmercury formation was inhibited in MS, probably due to increased complexation of Hg2+ with organic matter and adsorption of Hg to MS. Furthermore, the mean value of KdT in MS was relatively high when compared to RS, which illustrates that MS sediments have more binding sites than RS for adsorption of Hg. 相似文献17.
Pedro Henrique Augusto Medeiros José Carlos de Araújo 《Journal of Soils and Sediments》2014,14(7):1216-1223
Purpose
The temporal variabilities of both soil erosion by water and sediment redistribution in watersheds are directly related to rainfall characteristics. The purpose of this work was to assess the temporal pattern of rainfall in a semiarid watershed in Brazil and explain how this feature controls soil erosion and sediment yield.Materials and methods
Daily and 5-min rainfall records were used to assess the temporal pattern down to the sub-hourly scale. To study the effect of the rainfall on sediment processes, erosivity and sediment yield at the Aiuaba (12 km2) and Benguê (933 km2) watersheds, Brazil were determined. Erosivity was calculated based on the rainfall kinetic energy method, while sediment yield was estimated from sediment rating curves and daily water discharge measurements.Results and discussion
A large portion of annual rainfall is restricted to a few rain events and strong concentration in the sub-daily scale occurs, producing high erosivity. The temporal concentration of erosivity is greater than that of rainfall; the 10th percentile of the highest magnitude events encompasses 51% of the precipitation, but 80% of the erosivity. The temporal concentration of sediment yield is more pronounced; 88 and 98% of the sediment yield for the Aiuaba and Benguê watersheds, respectively, are within the 10th percentile of events.Conclusions
The strong temporal concentration of precipitation causes events with high intensity and erosivity, thus allowing for soil detachment. Nonetheless, the low runoff rates limit downstream sediment transport. Such behavior produces a much higher temporal concentration of sediment yield, which reaches its maximal after a sequence of rainy days, when hydrological connectivity is enhanced and the sediments are propagated throughout the entire transport-limited system. 相似文献18.
Adriana Alves Pereira Bert van Hattum Abraham Brouwer Peter Michiel van Bodegom Carlos Eduardo Rezende Wim Salomons 《Journal of Soils and Sediments》2008,8(4):239-252
Background, aim, and scope
In water systems, water quality and geochemical properties of sediments determine the speciation of trace metals, metal transport, and sediment–water exchange, influencing metal availability and its potential effects on biota. Studies from temperate climates have shown that iron-ore mining and tailing wastewaters, besides being a source of trace metals, usually show high levels of dissolved ions and particulate suspended matter, thus having the potential of indirectly changing metal bioavailability. For the first time in the tropics, we identified the effects of iron-ore mining and processing on metal bioavailability in a coastal lagoon. With an extensive sampling scheme, we investigated the potential sources of metals; the links among metal levels in water, sediments, and invertebrates; and the contrasting effects on metal speciation and bioavailability.Methodology
The metals Fe, Mn, Al, Cr, Zn, Cu, Ni, Pb, Cd, Hg, and As were measured in water, sediments (surface and profiles), and invertebrates from Mãe-Bá Lagoon and in the sites directly influenced by the mining operations (tailing dams and nearby rivers). In addition, samples from two other lagoons, considered pristine, were analyzed. The study area is located in the southeast of Brazil (Iron Quadrangle Region and a coastal area of Espírito Santo State). General water characteristics included pH, dissolved organic carbon, alkalinity, and anion composition. Water metal speciation was assessed by a speciation model (Chemical Equilibria in Aquatic Systems). Grain-size distribution, organic carbon, carbonate, and acid volatile sulfide (AVS) were determined in sediments. Statistical methods included comparison of means by Mann–Whitney test, ordination and correlation analyses, and analysis of regression for geochemical normalization of metals with grain size.Results and discussion
The dissolved metal concentrations, the total metal levels in sediments, and the normalization based on the fine sediment fraction showed that the mining operations constitute potential sources of Fe, Mn, Cr, Cu, Ni, Pb, As, and Hg to Mãe-Bá Lagoon. However, trace metal availability was reduced because of increased pH, hardness, and sulfide content (356 μmol/g) in the sites influenced by the mining. The lagoon showed similar water chemistry as in the mining sites, with metal bioavailability further decreased by the presence of dissolved organic carbon and chloride. Although AVS levels in the lagoon were low (0.48–56 μmol/g), metal bioavailability was reduced because of the presence of organic matter. Metal levels in invertebrates confirmed the predicted low metal bioavailability in Mãe-Bá Lagoon. The lagoon was considered moderately contaminated only by Hg and As.Conclusions
The iron-ore mining and processing studied here constitute potential sources of metal pollution into the tropical lagoon. Contrary to expectations, however, it also contributes to reducing the overall metal bioavailability in the lagoon.Recommendations and perspectives
These findings are believed to be useful for evaluating metal exposure in a more integrated way, identifying not only the sources of pollution but also how they can affect the components involved in metal speciation and bioavailability in water systems, leading to new insights. 相似文献19.
Annie Melinda Paz-Alberto Arnel B. Celestino Gilbert C. Sigua 《Journal of Soils and Sediments》2014,14(1):251-258