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1.
以Leenheer的分组方法为基础 ,用XAD 8树脂将黄泥土中水溶性有机质 (DOM)按极性和电荷特性分为结构较为均一的不同组分 ,并采用元素分析、1 H NMR以及CP/MAS1 3 C NMR研究各组分的性质。初步认为 :三种不同利用方式下 (桑园、水田、水杉 )黄泥土中的DOM组成中疏水碱性组分 (HOB)含量很少 ,疏水中性组分 (HON)相对含量为 7%～ 1 5 %,亲水性组分 (HIM)是土壤DOM中最大组成部分 ,约占 35 %。元素分析、1 H NMR以及1 3 C NMR分析结果表明 :DOM各组分结构特征差异显著。HON以含有大量的长链烷烃为主要结构特征 ,并含有较多氨基酸、多肽类物质 ;疏水酸性组分 (HOA)的结构特征相似于土壤FA ,含有大量羧基 ,但与FA相比芳香族物质减少 ,碳水化合物增多 ;酸不溶组分 (AIM)以多酚类、腐殖质结合的碳水化合物为主要组成物质 ;HIM中则含有大量碳水化合物。 相似文献
2.
Molecular weight-dependent electron transfer capacities of dissolved organic matter derived from sewage sludge compost 总被引：1，自引：1，他引：0
Yong Yuan Shungui Zhou Tian Yuan Li Zhuang Fangbai Li 《Journal of Soils and Sediments》2013,13(1):56-63
Purpose
Dissolved organic matter (DOM) has been shown to be an efficient electron transfer facilitator in biogeochemical reactions due to its ability to mediate redox reactions. It has been known that various fractions of DOM differed in their chemical and biogeochemical behaviors in environment. However, there has been relatively little work directed at predicting the dependence of redox properties of DOM on its fractions.Materials and methods
DOM was extracted from sewage sludge compost. Freeze-dried DOM was grouped into three fractions of different molecular sizes (<3,500, 3,500–14,000, and >14,000 Da) using dialysis bags (Spectra/Por 3 and 4, Spectrum Industries, California, US). Cycle voltammetry was used to investigate the redox behavior of the fractions. Chronoamperometry was employed to study their electron accepting capacities and electron donating capacities by applying fixed positive or negative potential to the working electrode in a conventional three-electrode cell. Fourier-transform infrared and three-dimensional excitation/emission matrix fluorescence spectroscopies were used to determine the functional groups in the fractions. Shewanella putrefaciens 200 (SP200) and Klebsiella pneumoniae L17 (L17) were used for all microbial iron(III) reduction experiments.Results and discussion
Electrochemical methods show that the electron transfer capacity (ETC) of DOM depends on its molecular weight, and ETC is in the order of high-molecular weight DOM (H-DOM) > moderate-molecular weight DOM > low-molecular weight DOM. The same trend is discovered in the DOM-stimulated iron(III) oxide bioreduction where DOM fractions act as electron shuttles transferring electrons from the Fe(III)-reducing bacteria to the iron oxide. Both spectroscopic and cyclic voltammogram assays show the highest abundance of redox moieties associated to H-DOM, which is possibly responsible for its strongest electron-shuttling ability.Conclusions
DOM has a wide molecular weight (MW) distribution due to the complexity of its chemical composition and structure. In addition to structural variations, DOM fractions with different MW have different redox properties and electron-shuttling capacities in microbial Fe(III) reduction. The results are of great significance for further studies on DOM geochemical behavior in environment. 相似文献3.
Guixue Song Rajaa Mesfioui Aaron Dotson Paul Westerhoff Patrick Hatcher 《Journal of Soils and Sediments》2018,18(4):1265-1278
Purpose
Dissolved organic matter (DOM) composition is influenced by and modulates biogeochemical processes, yet DOM characterization techniques are challenged by its heterogeneous properties and structures. In this paper, ultrahigh electrospray ionization Fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometry is used to characterize previously isolated and well-characterized four DOM fractions from a water reservoir in the southwestern part of the USA.Materials and methods
About 50–60 L water samples were collected from Lake Pleasant (a water reservoir of Colorado River) and isolated and fractionated using a sequential isolation and fractionation procedure. DOM was firstly fractionated to the colloids and soluble permeate, then hydrophobic acids (HPO-A) and neutrals (HPO-N) plus amphiphilic acids (AMP-A) and neutrals (AMP-N) were fractionated using the resin-in-tandem procedure. Approximately 0.7 mg sample was dissolved in 250 μL methanol/water mixture (1:1, v/v) and diluted twice with 0.1 % (by volume) NH4OH (in 1:1 methanol/water, v/v) and measured by ESI-FTICR in negative ion mode.Results and discussion
In the m/z range of <700, among the sum of 4107 peaks, HPO-N contained the most assigned 1763 molecules and HPO-A, AMP-N, and AMP-A contained 971, 990, and 293, respectively. Acid fractions were relatively more oxygenated than the corresponding neutrals. Except for the major assigned CHO molecules, a high portion of heteroatom-containing molecules were assigned in the neutral fractions. Van Krevelen and Venn diagrams analyses showed significant molecular differentiation among the fractions. Among the assigned formulas, the Venn diagram indicated only a small portion (<4 %) of distinct formulas overlapped. S-containing molecules were efficiently ionized and identified in the neutrals. Some of the S1-containing compounds with high signal magnitudes are tentatively assigned to alkylbenzene sulfonates and their biodegradation and biotransformation derivatives indicating anthropogenic input on site.Conclusions
By using the XAD resin-in-tandem approach and FTICR-MS, numbers of DOM molecules in fractions were distinctly separated, accordingly the complexity of DOM was reduced. Furthermore, to a great extent, the compositions and structures of each fraction in the molecular level are remarkably different as evidenced by only small portion of molecules overlapping.4.
Garrett McKay Jonathan L. Kleinman Kimberly M. Johnston Mei Mei Dong Fernando L. Rosario-Ortiz Stephen P. Mezyk 《Journal of Soils and Sediments》2014,14(2):298-304
Purpose
The objective of this study was to evaluate the effect of the physicochemical properties of five dissolved organic matter (DOM) isolates on their reactivity with the hydroxyl radical (HO·) in water.Materials and methods
Five DOM isolates were purchased from the International Humic Substance Society (IHSS). Weight average molecular weight (M W) of these samples was quantified using size exclusion chromatography based on polyethylene glycols as reference standards. Functional group and elemental composition of the DOM samples were available from the IHSS website. Room temperature rate constants were measured using electron pulse radiolysis.Results and discussion
Five IHSS standards were examined in this study: two soil organic and three aquatic organic matters. The composition varied from samples that had primarily aliphatic carbon (Pony Lake fulvic acid) to mostly aromatic carbon moieties (Elliot Soil humic acid). The M W values of the five samples ranged from 2,400 to 4,100 Da, with an average value of 3,060 Da. Second-order reaction rate constants between DOM and HO· (k DOM-HO·) were measured using thiocyanate competition kinetics, giving values ranging from 1.21 to 10.36?×?108 MC ?1?s?1. The k DOM-HO· values were not found to correlate with either M W or the aliphatic-aromatic carbon ratio, which is consistent with previous reports looking at natural organic matter (NOM), but is different to reports on size-fractionated (ultrafiltration through 15–1 kDa membranes) effluent organic matter (EfOM). We attribute this difference to the larger molecular weight distributions in size-fractionated EfOM compared to NOM.Conclusions
The k DOM-HO· values in this study ranged over a factor of 10, suggesting that hydroxyl radical reactivity does depend on the sample composition; however, no major correlation was found between the measured reactivity and bulk physicochemical properties of DOM. 相似文献5.
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6.
Purpose
In lake restoration, the redox sensitivity of iron (Fe)?Cphosphorus (P) compounds has been regarded as detrimental for a sustainable increase in sedimentary P retention since developing low redox potentials release Fe-bound P. Thus, Fe salts alone have rarely been used successfully to inactivate sediment P, and there are no studies on the long-term effects of in-lake Fe applications on P retention. Here, we analyzed for how long, and how efficiently, a single and continuous Fe application can affect the P budget of lakes.Materials and methods
Two aerated lakes in Berlin, Germany were compared: Lake Tegel (TEG) experienced a continuous Fe supply via its tributaries, while Lake Gro?-Glienicke (GGS) was treated once with Fe in the winter of 1992/1993. By controlling the operation of aerators, their effectiveness on P exchange at the sediment?Cwater interface (non-aerated vs. aerated) was directly compared in spring and autumn between 2008 and 2010. The amount of P controllable by aeration (P control) was experimentally determined by non-aerated vs. aerated sediment cores (at 10 and 16?°C). Core stratigraphy of Fe was observed by high-resolution ??X-ray fluorescence analysis.Results and discussion
In TEG, the mobility of Fe was limited due to its sulfidic fixation, and thus Fe only accumulated slightly at the sediment surface (Fe/P ratio, ??3). P control corresponded to only 4?% of the P content of the lake and 18?% of P loading. Hence, aeration only slightly influenced trophy-relevant epilimnetic P. In GGS, the single Fe application still ensures a high P binding ability of sediment since Fe relocated towards the surface (Fe/P ratio, ??7). P control corresponded to 38?% of the P content of the lake and 74?% of annual P loading. Thus, the P release is not relevant for the P supply to the epilimnion since with the lake??s overturn P is co-precipitated by the hypolimnetically accumulated Fe.Conclusions
When external P loading is sufficiently reduced, as in GGS, amendments to Fe precipitants can increase sediment P retention in a redox-dependent manner over the long term. Thus, the redox-dependent mobility of Fe should no longer be regarded as a disadvantage of Fe-containing precipitants. To compensate for co-precipitation and complexation of Fe with sediment organic matter, a high Fe dosage (??200?g?m?2) is needed. 相似文献7.
Electron transfer capacity of soil dissolved organic matter and its potential impact on soil respiration 总被引：1，自引：0，他引：1
Purpose
Soil dissolved organic matter (DOM) as the labile fraction of soil organic carbon (SOC) is able to facilitate biogeochemical redox reactions effecting soil respiration and carbon sequestration. In this study, we took soil samples from 20 sites differing in land use (forest and agriculture) to investigate the electron transfer capacity of soil DOM and its potential relationship with soil respiration.Materials and methods
DOM was extracted from 20 soil samples representing different land uses: forest (nos. 1–12) and agriculture (nos. 13–20) in Guangdong Province, China. Chronoamperometry was employed to quantify the electron transfer capacity (ETC) of the DOM, including electron acceptor capacity (EAC) and electron donor capacity (EDC), by applying fixed positive or negative potentials to a working electrode in a conventional three-electrode cell. The reversibility of electron accepting from or donating to DOM was measured by applying switchable potentials to the working electrode in the electrochemical system with the multiple-step potential technique. Carbon dioxide produced by soil respiration was measured with a gas chromatograph.Results and discussion
Forest soil DOM samples showed higher ETC and electron reversible rate (ERR) than agricultural soil DOM samples, which may be indicative of higher humification rate and microbial activity in forest soils. The average soil respiration of forest soil (nos. 1–12) and agricultural soil (nos. 13–10) was 26.34 and 18.58 mg C g?1 SOC, respectively. Both EDC and EAC of soil DOM had close relationship with soil respiration (p?<?0.01). The results implied that soil respiration might be accelerated by the electroactive moieties contained in soil DOM, which serve as electron shuttles and facilitate electron transfer reactions in soil respiration and SOC mineralization.Conclusions
DOM of forest soils showed higher ETC and ERR than DOM of agricultural soils. As soil represents one of the largest reservoirs of organic carbon, soil respiration affects C cycle and subsequently CO2 concentration in the atmosphere. As one of the important characteristics of soil DOM related to soil respiration, ETC has a significant impact on greenhouse gas emission and soil carbon sequestration but has not been paid attention to. 相似文献8.
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9.
Purpose
Using two fractions of dissolved organic matter (DOM) with different polarity, we carried out the experiments with standard batch equilibration, soil column leaching, and soil thin layer chromatography to investigate the behavior of the herbicide prometryne in soils. The purpose of the study was to: (1) separate DOM into hydrophilic matter and hydrophobic acid forms and characterize their chemical properties; (2) analyze interaction between the DOM fractions and prometryne in soils. 相似文献10.
土地利用方式对土壤溶解性有机碳组成的影响 总被引：7，自引：0，他引：7
选取河北曲周、北京顺义和山东寿光的成对的农田(小麦-玉米轮作)和菜田土壤为研究对象,比较两种土地利用方式下DOC的含量、剖面分布以及组成特征。结果表明:与农田相比,菜田表层有机碳(SOC)与全氮(TN)含量上升。其中菜田有机碳含量较农田增加3.16%~47.4%,全氮含量增加3.09%~64.1%。土壤C/N与pH降低。无论是在农田还是菜田,DOC含量均随着土壤深度增加而显著降低;三地区菜田表层DOC含量平均为农田DOC含量的1.70倍;DOC与SOC成显著正相关关系。两种土地利用方式下,DOC组成中亲水组分(H IM)比例最高,其次为憎水酸性组分(HOA),憎水中性物质(HON)和憎水碱性物质(HOB)的含量最低;菜田中憎水酸性物质比例为19.0%~26.7%,农田憎水酸比例为14.83%~16.42%;寿光地区农田与菜田憎水酸含量差异显著(p<0.05),可能与寿光菜田土壤较高的SOC含量和较低的pH有关。三地区中菜田中憎水性物质与亲水性物质比例分别为0.30、0.39、0.41,反映了菜田中存在着不同程度的腐殖化现象。总之,农田转变为菜田后,显著影响了DOC的数量和质量。 相似文献
11.
Guixue Song Etelvino H. Novotny Karl G. Richards Michael H. B. Hayes 《Journal of Soils and Sediments》2018,18(11):3197-3214
Purpose
Dissolved organic matter (DOM), a heterogeneous mixture of low concentrations of organic matter draining from soils, plays a significant role in soil C cycling and in nutrient and pollutant transport. DOM from undisturbed soil profiles has rarely been studied. Hydrophobic acids (Ho) and hydrophilic acids (Hi), the major components of DOM, were recovered, using XAD-8 and XAD-4 resins in series, from waters draining in winter and in spring periods from well-drained and poorly drained Irish grassland soil profiles in lysimeters.Materials and methods
Waters were collected from 45 soil undisturbed lysimeters at the Teagasc Research Centre, Johnstown Castle, Wexford, Ireland. Four Irish representative soils had been collected as undisturbed 1.0-m-deep monoliths, transported to the experiment site and arranged randomly in an experimental facility. Water collections were carried out in winter and spring periods. The DOM was isolated and fractionated using an XAD-8 and XAD-4 resins in-tandem procedure, and hydrophobic acids (Ho) and hydrophilic acids (Hi) were isolated.Results and discussion
The amounts of DOM recovered in the winter period were much greater than those in the spring period, and the soil types had only minor influences on the DOM concentrations recovered. The Ho and Hi fraction contents ranged from 62 to 90 and 10 to 28%, respectively, of the total DOM content extracted. The Hi acids were most enriched in 13C, and considered to reflect greater microbial inputs. The neutral sugar (NS) contents for the Ho and Hi fractions were in the range of 15 to 52 μg mg?1, with the Hi fraction most enriched. The amino acids (AAs) for the Ho and Hi fractions varied from 0.6 to 2.4%, and the total AAs and NS of the Ho acids were well correlated. The DOM fractions from the drainage waters contained much less AAs and NS than the corresponding fractions in the parent soils. The solid- and liquid-state NMR data indicated organic structures with low aromaticity, significant amounts of carbohydrate and with lesser amounts of peptide structures, and with long-chain methylene (CH2)n and methine (-CH-) groups.Conclusions
The application of a variety of wet chemistry and of spectroscopy procedures has given a more in-depth awareness of the compositions of the DOM in the drainage waters from four different soils in 1.0-m-deep lysimeter arrangements. Based on wet chemistry analyses, and FTIR and liquid- and solid-state NMR spectrometry, it is clear that there are some differences between the compositions of the DOM fractions recovered. Alkyl functionalities dominated the structures. These included significant amounts or O-alkyl (predominantly carbohydrate), and with lesser (and variable amounts in the different fractions) aromatic structures (to which aromatic amino acid components were considered to be significant contributors), and with no evidence for lignin-derived structures The results suggest that, during residence in the soil solution, microbiological processes transform the SOM components released into products that are greatly different from their materials of origin in the SOM.12.
Qunhe Wu Jiaying Zhang Renduo Zhang Ni Xu Chongyang Li 《Journal of Soils and Sediments》2013,13(5):943-952
Purpose
The source and diagenesis of sediment organic matter (OM) based on amino sugar yields and compositions were investigated in sediment samples collected along a reach of the upper Pearl River Estuary in south China.Materials and methods
Sediment samples were collected from the estuary. Three sediment size fractions—coarse particulate OM (CPOM), fine particulate OM (FPOM), and ultrafiltered dissolved OM (UDOM)—were analyzed for total hydrolysable amino sugars (THAS), total organic carbon (TOC), and total nitrogen (N).Results and discussion
THAS contributed much more to sediment TOC and total N in UDOM than in CPOM and FPOM. Percentages of TOC as THAS increased with increasing sediment size. The low glucosamine/galactosamine ratios indicated a relatively large bacterial contribution to the sediment OM size fractions and the less reactive nature of sediment OM in the upper Pearl River Estuary. However, the depletion in muramic acid in the three sediment fractions, especially in UDOM, suggested that living bacteria or intact peptidoglycan units were not a major contributor to sediment OM.Conclusions
The increases of TOC as THAS and C-normalized yields of THAS with the different sediment size fractions demonstrated that they could be used as diagenetic indicators. 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.
Eirin Sva Stomperudhaugen Katherine Langford Morten Schaanning Ketil Hylland 《Journal of Soils and Sediments》2014,14(8):1469-1478
Purpose
The aim of this study was to quantify the release of the hydrophobic contaminant emamectin (EMA) from marine sediments in response to inputs of organic material (OM) and/or oil, in the presence or absence of two different bioturbating species. Specifically, it was designed to test whether oil would decrease the release of EMA and whether OM and/or the presence of bioturbating macrofauna would increase the release of EMA from sediment.Materials and methods
Experimental sediments were spiked with EMA (5 μg kg?1 wet sediment). The different treatments were prepared by the addition of OM (310 g algae m?2) and/or an aliphatic oil (29.6 g oil m?2). In addition, two bioturbating species, Brissopsis lyrifera or Ennucula tenuis, were added in some aquaria, resulting in a total of 12 treatments with four replicates each. Water samples for analyses of silicate and EMA and sediment samples for analyses of total organic carbon (TOC) were taken at the start and end of the experimental exposure. In addition, oxygen was measured during the experimental period of 8 days. Fluxes were calculated and compared between treatments using generalised linear models (GLMs).Results and discussion
The EMA release flux was significantly increased in treatments with added OM, possibly reflecting the presence of soluble complexes formed between EMA and dissolved OM. The presence of B. lyrifera caused a small, but statistically significant, increase in EMA release from sediment. This species would be expected to have a stronger effect on bioirrigation and particle mixing than E. tenuis, particularly when the population density of the latter species is low (as in the present experiment). There were no consistent effects of oil in this experiment, but the presence of oil decreased the EMA release flux when co-occurring with added OM and/or B. lyrifera. Increased retention of hydrophobic contaminants in the presence of oil is consistent with the existing literature on contaminant fate.Conclusions
The results from this study highlight the need to consider both the infauna present in polluted areas and the level of organic enrichment of the sediment when modelling the environmental fate of hydrophobic contaminants. It also highlights that labile OM and refractory oil appear to differ in their effects on the remobilisation of hydrophobic organic contaminants, by reducing and increasing release, respectively. 相似文献15.
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16.
Goal, Scope and Background
Distribution of hydrophobic organic contaminants in abiotic compartments is essential for describing their transfer and fate in aquatic ecosystems. Taihu Lake is the third largest freshwater lake in China. Water quality of Taihu Lake has deteriorated greatly during the last decades and has threatened the water supply. The aim of the present study was to investigate the partitioning of polycyclic aromatic hydrocarbons (PAHs) among overlying water, suspended particulate matter (SPM), sediments, and pore water in Meiliang Bay, Taihu Lake and to provide useful information for the ecological engineering in this area.Materials and Methods
Overlying water and surface sediment were sampled from six sites in Meiliang Bay, Taihu Lake, China. Within 72 h of sampling, sediments were centrifuged to obtain the pore water. Overlying water samples were filtered to separate dissolved and SPM samples. After extraction, samples were purified following a clean-up procedure. PAH fraction was obtained by elution with a mixture of hexane: DCM (7:3, V/V) and analyzed by GC/MS.Results
PAHs concentrations in overlying water varied from 37.5 ng/L to 183.5 ng/L. Concentrations of PAHs in pore water were higher than those in overlying water. The total concentrations of 16 priority PAHs in sediments ranged from 2091.8 ng/g-dw to 4094.4 ng/g-dw. PAHs concentrations on SPM were decreased with suspended solid concentrations (SSC). Total PAHs concentrations on SPM varied in the range of 3369.6 ng/g-dw to 7531.1 ng/g-dw. The partition coefficients between sediment and overlying water (log K oc) for PAHs with log K ow<5 were positively correlated with their octanol-water partition coefficients (log K ow) (n=39, r=0.79, p<0.0001). Partition coefficients between sediment and pore water (log K oc′) for all PAHs were also significantly correlated with their log K ow values (n=48, r=0.82, p<0.0001).Discussion
In general, PAHs derived from combustion sources tend to bind strongly to soot particles in natural sediment. Consequentially, K oc values observed in the natural environment could be orders of magnitude higher than those predicted by linear correlation relationships under laboratory conditions. In the present study, the ratio of log K oc values to log K ow values falls consistently above 1, indicating that the sediment soot carbon in the bay was more attractive for PAHs than n-octanol. The log K oc′ was also higher than that predicted under laboratory conditions, suggesting that the measured pore water PAH concentrations were lower than those predicted. That is to say, not all the sediment PAHs can be available to partition rapidly into sediment pore waters. A variation in soot content is a possible reason. Furthermore, concentrations of PAHs on SPM were higher than those in sediments. The compositions of PAHs on SPM and in sediments were similar, indicating the importance of re-suspension process of sediments in the partitioning process of the shallow lake.Conclusions
The results indicated the equilibrium partitioning model could be used to predict PAHs distribution in various phases of a shallow lake in the stagnation period, but re-suspension processes should be considered to modify the relationship between log K ocs and log K ows.Recommendations and Perspectives
Concentration, particle size and composition of resuspended particles could affect the relationship between log K ocs and log K ows. Further work should be done under field conditions, especially where a steady thermodynamic equilibrium state could be assumed.17.
Burton C. Suedel Charles H. Lutz Joan U. Clarke Douglas G. Clarke 《Journal of Soils and Sediments》2012,12(6):995-1003
Purpose
Sediment resuspension is among the most widely cited concerns that lead to restricted dredging timeframes. Protection of fish species is a primary concern regarding the effects of dredging operations, yet experimental data establishing thresholds for uncontaminated suspended sediment effects are largely lacking. We conducted research to determine suspended sediment effects on walleye (Sander vitreus) egg hatching success and gross morphology following exposures mimicking sediment resuspension during dredging operations.Materials and methods
Newly spawned eggs of northern and southern walleye strains were continuously exposed for 3?days to suspended sediment concentrations of 0, 100, 250, and 500?mg?l?1, using sediment from Maumee Bay, OH, USA. These concentrations spanned the range measured in the vicinity of dredging operations in the Western Basin of Lake Erie.Results and discussion
Northern and southern strain egg hatching rates were 53% and 39% of exposed eggs and 82% and 74% of viable eggs exposed, which are within reported ranges for this species. Data indicated no statistically significant effects of suspended sediment on hatching success. Gross morphological observations of exposed fry yielded no evidence of detrimental effects.Conclusions
Experimental results indicated that walleye eggs are relatively tolerant to exposures likely to be encountered at dredging projects as performed in the Great Lakes region. Our results suggest that, given detailed knowledge of dredging project site-specific conditions and the mode of dredging to be used, better informed decisions can be made regarding adequate protective management practices. In many cases, flexibility could be given to the dredging contractor while maintaining a very low probability of risk to walleye spawning habitat. 相似文献18.
Influence of origin and properties of dissolved organic matter on the partition of polycyclic aromatic hydrocarbons (PAHs) 总被引：8，自引：0，他引：8
We investigated dissolved organic matter (DOM) from soil, sewage sludges, water from waste disposal sites, and composts as sorbents and potential carriers for hydrophobic polycyclic aromatic hydrocarbons (PAHs) in soil. Partition coefficients (expressed log KDOC) for two 5-ring compounds were 4·8–4·9 for DOM from soil, 4·5–47 from composts, and 4·3–4·4 from sewage sludges. The DOM from compost and sewage sludge can influence the transport of non-ionic organic contaminants because of the large concentrations of dissolved organic carbon (DOC) released from these materials. Leachates from waste disposal sites did not sorb PAHs. The DOM from compost contained a large percentage of organic molecules > 14 000 Da (32–46%), whereas DOM from waste disposal leachates contained only 7-lo%, and so bound less PAHs. The percentage of total hydrophobic components, as characterized by XAD-8 chromatography, was 50 ± 9% for most of the DOM solutions and did not express the differences in affinity of the organic sorbents to PAHs in the same way as the KDOC values. Isolated molecular-weight fractions of DOM from composts sorbed benzo(k)fluoranthene in each fraction. The log KDOC values were 4·1–4·3 for both fractions, < 1000 and 1000–14 000 Da, and 4·8–5·0 for the fraction > 14 000 Da. The interaction of PAHs with DOM < 1000 Da cannot be explained by partitioning within intramolecular nonpolar environments of dissolved macromolecules; rather it seems to be due to the amphoteric properties of DOM. This type of interaction of PAHs with small DOM molecules might affect the mobility of hydrophobic organic chemicals in soils. 相似文献
19.
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20.
Sehee Oh Moon-Kyung Kim Young-Min Lee Kyung-Duk Zoh 《Water, air, and soil pollution》2011,220(1-4):353-363
This study was conducted to evaluate the contribution of environmental factors such as solar radiation and dissolved organic matter (DOM) on the photo-induced dissolved gaseous mercury (DGM) production through laboratory experiments using field water samples collected from wetlands. DGM production was more significantly influenced by UVB intensity than UVA. DGM formation was also significantly affected by DOM chemical structure/composition rather than its concentration. Increasing NO 3 ? concentration limited DGM production, but photo-induced Hg oxidation stimulated by NO 3 ? would possibly occur when the NO 3 ? level is more than twice the DOC level. The addition of phosphorus into the field water samples induced a slight increase of DGM production; however, the addition of nitrogen decreased DGM formation, suggesting that an increase of limiting nutrients in water may promote biotic DGM production. Experiments using a Selenastrum capricornutum monoculture solution showed that cell density had a positive effect on DGM production. Moreover, the difference in DGM production between filtered and unfiltered samples showed that S. capricornutum significantly produced biotic DGM under UVA irradiation. Finally, our results imply that environmental factors such as light intensity, DOM sources, and site-specific microorganisms can significantly affect photo-induced Hg transformation. 相似文献