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Mercury cycling between the water column and surface sediments in a contaminated area

Ramalhosa, Elsa; Río-Segade, Susana; Pereira, Eduarda; Vale, Carlos; Duarte, Armando
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.64%
Mercury cycling in the water column and upper sediments of a contaminated area, the Largo do Laranjo, Aveiro (Portugal), was evaluated after determination of reactive and non-reactive mercury concentrations in the water column and pore waters of sediments, collected in several places of this bay. In the water column, reactive mercury concentrations varied between 10 and 37 pmol dm−3, the highest values being observed near the mercury anthropogenic source. However, reactive mercury was a narrowly constrained fraction of the total mercury, making up only 4–16% of the total, showing evidence of the importance of dissolved organic matter on mercury transport. In sediments, higher concentrations of mercury were also determined near industrial discharges. Results indicate the existence of an equilibrium between solid and liquid phases, determined by solid sediment/pore water distribution coefficients. Much of the mercury present in the solid fraction is associated with organic matter (r=0.837) and iron oxyhydroxides (r=0.919), but as oxides begin to dissolve in reduced sediments and organic matter decays, the adsorbed mercury is released. In fact, the mercury concentrations in pore waters of those contaminated sediments largely exceeded the values determined in the water column. As molecular diffusion may contribute to the dissolved mercury distribution in the overlying water column...

Storage and export of mercury from a contaminated bay (Ria de Aveiro, Portugal)

Ramalhosa, Elsa; Monterroso, Paulo; Abreu, Sizenando; Pereira, Eduarda; Vale, Carlos; Duarte, Armando
Fonte: Kluwer Academic Publishers Publicador: Kluwer Academic Publishers
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.17%
Mercury has been determined in water, suspended particulate matter (SPM) and sediments (solid fraction and pore water) collected in a heavily contaminated confined area (Largo do Laranjo) of the Ria de Aveiro. Mercury has been analysed in seabass (Dicentrarchus labrax) captured in several locations of the lagoon. The levels of mercury in water and SPM in the contaminated sampled places fluctuated daily with the tide (from 10 to 53 ng.dm-3 and 3.5 to 26 ug.g-1, respectively), indicating the export at the tidal rhythm. Bottom sediments exhibited higher concentrations, the maximum (48 ug.g-1) occurring near the anthropogenic source at depths corresponding to the periods of higher industrial discharges. Mercury concentrations in pore waters (max. 80 ng.dm-3) exceed the values found in the water column and were higher at depths where Acid Volatile Sulphides (AVS) presented broad maximums. This implies a remobilization at anoxic conditions. However, the export across the sediment-water interface predicted through molecular diffusion is low (between 1 to 4 x 10-3 ng.cm-2.h-1) in comparison to the industrial input. The anthropogenic mercury appears to be rapidly accumulated in seabass, a predator fish that enter seasonally in Largo do Laranjo.

On-line redox speciation analysis of antimony using L-proline immobilized on controlled pore glass and hydride generation inductively coupled plasma optical emission spectrometry for detection

Menegario, Amauri A.; Smichowski, Patricia; Tonello, Paulo S.; Polla, Griselda; Oliveira, Eliane P.; Santelli, Ricardo E.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 131-136
ENG
Relevância na Pesquisa
36.17%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); L-proline was immobilized on controlled pore glass to study the ability of this material for the separation and preconcentration of Sb(III) and Sb(V). The substrate was packed in a minicolumn and incorporated in a flow injection system. The effluents of the on-line solid phase extraction (before and after elution) were directly coupled to the hydride generation inductively coupled plasma optical emission spectrometry system. The effect of pH, sample (and eluent) volume, flow rates of sample loading and elution on separation of Sb(III) e Sb(V) were evaluated. Our experiments demonstrated that Sb(V) was not retained and it was selectively determined during the loading step, while retained Sb(III) was determined afterelution. The proposed system was also used for the selective preconcentration of Sb(III). In this case, a preconcentration factor of 11 and a limit of detection of 90 ng L-1 for Sb(III) were achieved when 8 mL of sample were loaded into the column. The speciation analysis of inorganic Sb in river water and effluent samples was performed using the proposed method. The values obtained for total Sb (obtained by sum of Sb(III) and Sb(V)) were in good agreement with expected values. Recoveries of Sb(III) and Sb(V) in the river water Standard Reference Material 1640 (from National Institute of Standard and Technology) and spiked river waters were between 83 and 111%. (C) 2008 Elsevier B.V. All rights reserved.

Fluorescence and DOC contents of estuarine pore waters from colonized and non-colonized sediments: Effects of sampling preservation

OTERO, M; MENDONCA, A; VALEGA, M; Santos, Eduarda E.B.H.; Pereira, Eduarda; Esteves, Valdemar I.; Duarte, Armando
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.71%
The influence of the colonization of salt marsh sediments with Halimione portulacoides was evaluated by analysing the fluorescent dissolved organic matter (FDOM) in sediment pore waters from a salt marsh at different depths. Cores of sediments at colonized and non-colonized sites were collected from a coastal lagoon (Ria de Aveiro, Portugal). The DOC content of extracted pore waters was determined and characterized by synchronous molecular fluorescence (Dk = 60 nm) and UV–visible spectroscopies. The common practice of freezing sediment cores for further and later chemical investigation was shown not to be an appropriate methodology of sample preservation. On the contrary, freezing of extracted and filtered pore water seemed not to affect either the DOC content or the fluorescence properties of pore waters. Two types of fluorescent substances were found in the pore waters spectra; one corresponding to humic-like substances and another one resembling proteins. However, major differences were found in the spectra of pore waters depending on both depth and the presence/absence of vegetation colonization

Metal-contaminated sediments in a semi-closed basin: Implications for recovery

Monterroso, P.; Pato, P.; Pereira, M. E.; Millward, G. E.; Vale, C.; Duarte, A.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.49%
Sediment cores, collected from a contaminated zone in the Ria de Aveiro (Portugal), were sectioned, under nitrogen, and centrifuged to remove the pore waters. The sediment characteristics, including acid volatile sulphide (AVS) concentrations, were determined, together with total and available metals (Fe, Mn, Cd, Cu, Pb, Zn) and the total dissolved metals in the pore waters. Peak concentrations in total metals of the sediments were observed at various depths in the core as a result of time-dependent, industrial discharges. The fraction of total metal released by a mixture of hydroxylamine hydrochloride and acetic acid (HAA) ranged from 24% for Cu to 74% for Zn and enzymatic digestion by proteinase K released <10% of total metal. The pore waters had elevated dissolved metal concentrations concomitant with the peaks in total and available metal and with a maximum in AVS concentration. Equilibrium calculations indicated that the major dissolved phase species was MHS2−, with minor quantities of M(HS)2. The diffusive fluxes for sediment–water exchange of the metals were insignificant, the mobility of the metals being hindered by sulphide formation. Thus, the metals are likely to remain trapped in these sediments, thereby delaying recovery from contamination.

Mercury cycling between the water column and surface sediments in a contaminated area

Ramalhosa, E.; Segade, S. R.; Pereira, E.; Vale, C.; Duarte, A.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.64%
Mercury cycling in the water column and upper sediments of a contaminated area, the Largo do Laranjo, Aveiro (Portugal), was evaluated after determination of reactive and non-reactive mercury concentrations in the water column and pore waters of sediments, collected in several places of this bay. In the water column, reactive mercury concentrations varied between 10 and 37 pmol dm−3, the highest values being observed near the mercury anthropogenic source. However, reactive mercury was a narrowly constrained fraction of the total mercury, making up only 4–16% of the total, showing evidence of the importance of dissolved organic matter on mercury transport. In sediments, higher concentrations of mercury were also determined near industrial discharges. Results indicate the existence of an equilibrium between solid and liquid phases, determined by solid sediment/pore water distribution coefficients. Much of the mercury present in the solid fraction is associated with organic matter (r=0.837) and iron oxyhydroxides (r=0.919), but as oxides begin to dissolve in reduced sediments and organic matter decays, the adsorbed mercury is released. In fact, the mercury concentrations in pore waters of those contaminated sediments largely exceeded the values determined in the water column. As molecular diffusion may contribute to the dissolved mercury distribution in the overlying water column...

Geochemistry of intertidal sediment pore waters from the industrialized Santos-Cubatão Estuarine System, SE Brazil

Gonçalves,Winston F.O.; Luiz-Silva,Wanilson; Machado,Wilson; Nizoli,Erico C.; Santelli,Ricardo E.
Fonte: Academia Brasileira de Ciências Publicador: Academia Brasileira de Ciências
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2012 EN
Relevância na Pesquisa
56.55%
The geochemical composition of sediment pore water was investigated in comparison with the composition of sediment particles and surface water in an estuary within one of the most industrialized areas in Latin America (Santos-Cubatão estuarine system, SE Brazil). Pore and surface waters presented anomalously high levels of F-, NH4+, Fe, Mn and P due to two industrial point sources. In the summer, when SO4(2-)/Cl- ratios suggested an enhanced sulfate reduction, the higher dissolved levels observed in pore waters for some metals (e.g., Cu and Ni) were attributed to reductive dissolution of oxidized phases. Results evidenced that the risks of surface water concentration increase due to diffusion or advection from pore water are probably dependent on coupled influences of tidal pumping and groundwater inputs.

Measurement of Acetate Concentrations in Marine Pore Waters by Using an Enzymatic Approach †

King, Gary M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1991 EN
Relevância na Pesquisa
46.25%
Acetate concentrations in marine and freshwater matrices were measured by an enzymatic technique which coupled the synthesis of acetyl coenzyme A to AMP production. The resulting AMP was assayed by a sensitive and relatively rapid high-pressure liquid chromatography method, using an aqueous, isocratic mobile phase for elution. The method was insensitive to the presence of seawater salts and required no sample prepurification or distillation. Propionate caused a minor, but statistically insignificant, interference when equimolar with acetate; butyrate caused no interference, even at relatively high concentrations. Detection limits for acetate were approximately 100 nM with a precision of about 5%. Pore waters from two intertidal sediments contained approximately 1 to 12 μM acetate; the concentrations were linearly but inversely correlated with porewater sulfate.

Regulation and function of the two-pore-domain (K2P) potassium channel Trek-1 in alveolar epithelial cells

Schwingshackl, Andreas; Teng, Bin; Ghosh, Manik; West, Alina Nico; Makena, Patrudu; Gorantla, Vijay; Sinclair, Scott E.; Waters, Christopher M.
Fonte: American Physiological Society Publicador: American Physiological Society
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.08%
Hyperoxia can lead to a myriad of deleterious effects in the lung including epithelial damage and diffuse inflammation. The specific mechanisms by which hyperoxia promotes these pathological changes are not completely understood. Activation of ion channels has been proposed as one of the mechanisms required for cell activation and mediator secretion. The two-pore-domain K+ channel (K2P) Trek-1 has recently been described in lung epithelial cells, but its function remains elusive. In this study we hypothesized that hyperoxia affects expression of Trek-1 in alveolar epithelial cells and that Trek-1 is involved in regulation of cell proliferation and cytokine secretion. We found gene expression of several K2P channels in mouse alveolar epithelial cells (MLE-12), and expression of Trek-1 was significantly downregulated in cultured cells and lungs of mice exposed to hyperoxia. Similarly, proliferation cell nuclear antigen (PCNA) and Cyclin D1 expression were downregulated by exposure to hyperoxia. We developed an MLE-12 cell line deficient in Trek-1 expression using shRNA and found that Trek-1 deficiency resulted in increased cell proliferation and upregulation of PCNA but not Cyclin D1. Furthermore, IL-6 and regulated on activation normal T-expressed and presumably secreted (RANTES) secretion was decreased in Trek-1-deficient cells...

Regulation of interleukin-6 secretion by the two-pore-domain potassium channel Trek-1 in alveolar epithelial cells

Schwingshackl, Andreas; Teng, Bin; Ghosh, Manik; Lim, Keng Gat; Tigyi, Gabor; Narayanan, Damodaran; Jaggar, Jonathan H.; Waters, Christopher M.
Fonte: American Physiological Society Publicador: American Physiological Society
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.08%
We recently proposed a role for the two-pore-domain K+ (K2P) channel Trek-1 in the regulation of cytokine release from mouse alveolar epithelial cells (AECs) by demonstrating decreased interleukin-6 (IL-6) secretion from Trek-1-deficient cells, but the underlying mechanisms remained unknown. This study was designed to investigate the mechanisms by which Trek-1 decreases IL-6 secretion. We hypothesized that Trek-1 regulates tumor necrosis factor-α (TNF-α)-induced IL-6 release via NF-κB-, p38-, and PKC-dependent pathways. We found that Trek-1 deficiency decreased IL-6 secretion from mouse and human AECs at both transcriptional and translational levels. While NF-κB/p65 phosphorylation was unchanged, p38 phosphorylation was decreased in Trek-1-deficient cells, and pharmacological inhibition of p38 decreased IL-6 secretion in control but not Trek-1-deficient cells. Similarly, pharmacological inhibition of PKC also decreased IL-6 release, and we found decreased phosphorylation of the isoforms PKC/PKDμ (Ser744/748), PKCθ, PKCδ, PKCα/βII, and PKCζ/λ, but not PKC/PKDμ (Ser916) in Trek-1-deficient AECs. Phosphorylation of PKCθ, a Ca2+-independent isoform, was intact in control cells but impaired in Trek-1-deficient cells. Furthermore...

Regulation of Monocyte Chemotactic Protein-1 secretion by the Two-Pore-Domain Potassium (K2P) channel TREK-1 in human alveolar epithelial cells

Schwingshackl, Andreas; Teng, Bin; Ghosh, Manik; Waters, Christopher M
Fonte: e-Century Publishing Corporation Publicador: e-Century Publishing Corporation
Tipo: Artigo de Revista Científica
Publicado em 15/08/2013 EN
Relevância na Pesquisa
36.08%
We recently proposed a role for the 2-pore-domain K+ (K2P) channel TREK-1 in the regulation of cytokine release from alveolar epithelial cells (AECs) by demonstrating decreased IL-6 secretion from TREK-1 deficient cells, but the effects of altered TREK-1 expression on other inflammatory mediators remain poorly understood. We now examined the role of TREK-1 in TNF-α-induced MCP-1 release from human A549 cells. We hypothesized that TREK-1 regulates TNF-α-induced MCP-1 secretion via c-Jun N-terminal kinases (JNK)- and protein kinase-C (PKC)-dependent pathways. In contrast to IL-6 secretion, we found that TREK-1 deficiency resulted in increased MCP-1 production and secretion, although baseline MCP-1 gene expression was unchanged in TREK-1 deficient cells. In contrast to TREK-1 deficient AECs, overexpression of MCP-1 had no effect on MCP-1 secretion. Phosphorylation of JNK1/2/3 was increased in TREK-1 deficient cells upon TNF-α stimulation, but pharmacological inhibition of JNK1/2/3 decreased MCP-1 release from both control and TREK-1 deficient cells. Similarly, pharmacological inhibition of PKC decreased MCP-1 secretion from control and TREK-1 deficient cells, suggesting that alterations in JNK and PKC signaling pathways were unlikely the cause for the increased MCP-1 secretion from TREK-1 deficient cells. Furthermore...

Revealing Sources and Distribution Changes of Dissolved Organic Matter (DOM) in Pore Water of Sediment from the Yangtze Estuary

Wang, Ying; Zhang, Di; Shen, Zhenyao; Feng, Chenghong; Chen, Jing
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 14/10/2013 EN
Relevância na Pesquisa
36.22%
Dissolved organic matter (DOM) in sediment pore waters from Yangtze estuary of China based on abundance, UV absorbance, molecular weight distribution and fluorescence were investigated using a combination of various parameters of DOM as well as 3D fluorescence excitation emission matrix spectra (F-EEMS) with the parallel factor and principal component analysis (PARAFAC-PCA). The results indicated that DOM in pore water of Yangtze estuary was very variable which mainly composed of low aromaticity and molecular weight materials. Three humic-like substances (C1, C2, C4) and one protein-like substance (C3) were identified by PARAFAC model. C1, C2 and C4 exhibited same trends and were very similar. The separation of samples on both axes of the PCA showed the difference in DOM properties. C1, C2 and C4 concurrently showed higher positive factor 1 loadings, while C3 showed highly positive factor 2 loadings. The PCA analysis showed a combination contribution of microbial DOM signal and terrestrial DOM signal in the Yangtze estuary. Higher and more variable DOM abundance, aromaticity and molecular weight of surface sediment pore water DOM can be found in the southern nearshore than the other regions primarily due to the influence of frequent and intensive human activities and tributaries inflow in this area. The DOM abundance...

Pore waters regulate ion permeation in a calcium release-activated calcium channel

Dong, Hao; Fiorin, Giacomo; Carnevale, Vincenzo; Treptow, Werner; Klein, Michael L.
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.08%
Calcium channel dysfunction is implicated in cardiac arrhythmias and immunodeficiency disorders. The recent publication of the crystal structure of a calcium ion channel denoted CRAC has allowed us to use atomic-level computer simulation to begin to understand the mechanism of ion permeation through this ubiquitous and vital cell entry pathway. Our computations identify pore water molecules as a crucial contributor in governing the channel conductance characteristics not only of the wild-type protein but also a disease-related mutant. The present study should be helpful for research designed to improve treatment of immune diseases caused by disrupted calcium signaling.

TRLFS study on the speciation of uranium in seepage water and pore water of heavy metal contaminated soil

Baumann, Nils; Arnold, Thuro; Lonschinski, Martin
Fonte: Springer Netherlands Publicador: Springer Netherlands
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.34%
In situ leaching of uranium ores with sulfuric acid during active uranium mining activity on the Gessenheap has caused longstanding environmental problems of acid mine drainage and elevated concentrations of uranium. To study there remediation measures the test site Gessenwiese, a recultivated former uranium mining heap near Ronnenburg/East Thuringia/Germany, was installed as a part of a research program of the Friedrich-Schiller University Jena to study, among other techniques, the phytoremediation capacity of native and selected plants towards uranium. In the first step the uranium speciation in surface seepage and soil pore waters from Gessenwiese, ranging in pH from 3.2 to 4.0, were studied by time-resolved laser-induced fluorescence spectroscopy (TRLFS). Both types of water samples showed mono-exponential luminescence decay, indicating the presence of only one major species. The detected emission bands were found at 477.5, 491.8, 513.0, 537.2, 562.3, and 590.7 nm in case of the surface water samples, and were found at 477.2, 493.2, 513.8, 537.0, 562.4, and 590.0 nm in case of the soil water samples. These characteristic peak maxima together with the observed mono-exponential decay indicated that the uranium speciation in the seepage and soil pore waters is dominated by the uranium (VI) sulfate species UO2SO4(aq). Due to the presence of luminescence quenchers in the natural water samples the measured luminescence lifetimes of the UO2SO4(aq) species of 1.0–2.6 μs were reduced in comparison to pure uranium sulfate solutions...

Chemical speciation of Zn, Cd, Cu, and Pb in pore waters of agricultural and contaminated soils using Donnan dialysis

Nolan, A.; McLaughlin, M.; Mason, S.
Fonte: Amer Chemical Soc Publicador: Amer Chemical Soc
Tipo: Artigo de Revista Científica
Publicado em //2003 EN
Relevância na Pesquisa
46.49%
Knowledge of trace metal speciation in soil pore waters is important in addressing metal bioavailability and risk assessment of contaminated soils. Numerous analytical methods have been utilized for determining trace metal speciation in aqueous environmental matrixes; however, most of these methods suffer from significant interferences. The Donnan dialysis membrane technique minimizes these interferences and has been used in this study to determine free Zn2+, Cd2+, Cu2+, and Pb2+ activities in pore waters from 15 agricultural and 12 long-term contaminated soils. The soils vary widely in their origin, pH, organic carbon content, and total metal concentrations. Pore water pM2+ activities also covered a wide range and were controlled by soil pH and total metal concentrations. For the agricultural soils, most of the free metal activities were below detection limit, apart from Zn2+ for which the fraction of free Zn2+ in soluble Zn ranged from 2.3 to 87% (mean 43%). Five of the agricultural soils had detectable free Cd2+ with fractions of free metal ranging from 59 to 102% (mean 75%). For the contaminated soils with detectable free metal concentrations, the fraction of free metal as a percentage of soluble metal varied from 9.9 to 97% (mean 50%) for Zn2+...

Volcanogenic sediment-seawater interactions and the geochemistry of pore waters

Schacht, U.; Wallmann, K.; Kutterolf, S.; Schmidt, M.
Fonte: Elsevier Science BV Publicador: Elsevier Science BV
Tipo: Artigo de Revista Científica
Publicado em //2008 EN
Relevância na Pesquisa
56.55%
Four volcanic ash-bearing marine sediment cores and one ash-free reference core were examined during research cruise RV Meteor 54/2 offshore Nicaragua and Costa Rica to investigate the chemical composition of pore waters related to volcanic ash alteration. Sediments were composed of terrigenous matter derived from the adjacent continent and contained several distinct ash layers. Biogenic opal and carbonate were only minor components. The terrigenous fraction was mainly composed of smectite and other clay minerals while the pore water composition was strongly affected by the anaerobic degradation of particulate organic matter via microbial sulphate reduction. The alteration of volcanic matter showed only a minor effect on major element concentrations in pore waters. This is in contrast to prior studies based on long sediment cores taken during the DSDP, where deep sediments always showed distinct signs of volcanic ash alteration. The missing signal of ash alteration is probably caused by low reaction rates and the high background concentration of major dissolved ions in the seawater-derived pore fluids. Dissolved silica concentrations were, however, significantly enriched in ash-bearing cores and showed no relation to the low but variable contents of biogenic opal. Hence...

Pore water composition of volcanogenic sediments from across the Central American Subduction Zone

Schacht, U.; Kutterolf, S.; Bartdorff, O.; Corrales Cordero, E.
Fonte: Elsevier Science BV Publicador: Elsevier Science BV
Tipo: Artigo de Revista Científica
Publicado em //2009 EN
Relevância na Pesquisa
36.6%
Subduction Zones are among the most dynamic tectonic environments on Earth. Thus, the Central American Suduction Zone became the focus of research cruise Meteor 66 since here the sediment cover is strongly influenced by the highly explosive volcanism along the Central American Volcanic Arc. The main focus of this study is to analyse the influence of alteration reactions on the chemical composition of pore waters extracted from volcanogenic surface sediments. During research cruise RV Meteor 66, a program of sampling and analysis of pore waters from retrieved sediment cores was carried out. Alkalinity, sulphate, calcium, magnesium, potassiumand silica concentration-depth profiles of deep-sea sediment coresweremeasured to define the ash alteration reactions that occur in surface sediments. The concentrationprofiles ofmajor cations showed no clear effects of ash alteration, which is in contrast to investigations performed on deep sediment cores (N100 m depth) during the Deep Sea (DSDP) and Ocean Drilling (ODP) Programs. However, no significant difference in dissolved Ca and Mg could be observed between the ash-bearing cores and the ash-free reference core, confirming that the distribution of alkaline earth elements in the surface sediments investigated in our study is not significantly affected by ash alteration. The missing signal of ash alteration is probably caused by low reaction rates and the high background concentration of major dissolved ions in the seawaterderived pore waters. Apart from the generally low reactivity of the investigated of the investigated sediments...

Mobility and storage of metals, metalloids and trace elements in disturbed acid sulfate soils from a tidal estuary in South Australia

Thomas, B.; Fitzpatrick, R.; Merry, R.; Hicks, W.
Fonte: UWA; DVD Publicador: UWA; DVD
Tipo: Conference paper
Publicado em //2010 EN
Relevância na Pesquisa
36.34%
In Australia, acid sulfate soils (ASS) are widespread in both coastal and inland settings where they pose environmental hazards from acidification and metal mobilisation. In this study, three saturated soil-sediment profiles from distinct positions in a disturbed tidal ASS landscape were hydrogeochemically characterised. The soil profile geochemical data and surface water chemistry were compared in order to find evidence of metal, metalloid and trace element mobilisation. The results showed that concentrations of Cu, Ni, Pb, Zn, S, Al, Mg and Fe were elevated in the near-surface, oxidised layers of sulfuric materials of the ASS profile and were marginally elevated within nearby hyposulfidic material in circum-neutral stream sediments. Metals and metalloids, including Ni, Zn, Al and Fe, were leached to pore waters in sulfuric materials from which a range of salt efflorescences had precipitated. Acidic drain waters also contained elevated Al, Fe and other major cations and anions, but did not contain detectible concentrations of trace elements. Nearby circumneutral stream waters only contained elevated concentrations of Fe. Leaching of trace metals was greatest at the surface of exposed sulfuric materials where salt efflorescences had formed. Covering sulfuric materials with mulch...

Sediment pore water distribution coefficients of PCB congeners in enriched black carbon sediment

MARTINEZ, ANDRES; O'SULLIVAN, COLIN; REIBLE, DANNY; HORNBUCKLE, KERI C.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.22%
More than 2300 sediment pore water distribution coefficients (KPCBi ds) of 93 polychlorinated biphenyls (PCBs) were measured and modeled from sediments from Indiana Harbor and Ship Canal. KPCBi ds were calculated from previously reported bulk sediment values and newly analyzed pore water. PCBs in pore waters were measured using SPME PDMS-fiber and ∑PCB ranged from 41 to 1500 ng L−1. The resulting KPCBi ds were ~ 1 log unit lower in comparison to other reported values. A simple model for the KPCBi d consisted of the product of the organic carbon fraction and the octanol-water partition coefficient and provided an excellent prediction for the measured values, with a mean square error of 0.09 ± 0.06. Although black carbon content is very high in these sediments and was expected to play an important role in the distribution of PCBs, no improvement was obtained when a two-carbon model was used.

Pore water chemistry of acid sulfate soils: Chemical flux and oxidation Rates

van Oploo, P; White, Ian; Ford, Philip; Melville, Michael D; MacDonald, Bennett
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.17%
Peeper pore water profiles above the oxidation front in acid sulfate soils (ASS) revealed unexpected differences in the elevation of the concentration maxima for chemical element species. These reflect the differing chemical and transport processes occurr