Seawater Dotaz Zobrazit nápovědu
A method for caesium concentration from North Sea and Baltic Sea seawater samples was tested and optimised for offshore concentration of radiocaesium and seawater volumes up to 150 L. The composite ion-exchanger PotassiumNickel Hexacyanoferrate in a Polyacrylnitrile binding matrix (KNiFC-PAN) with 80% of powdered KNiFC per gram of dry residue was used for this study. The optimised method achieved recoveries of around 99% with a bed volume (BV) of 50 mL of KNiFC-PAN and average flow rates of seawater of around 182 BV per hour (e.g. 9.1 L per hour).
The microbial diversity and functioning around oceanic islands is poorly described, despite its importance for ecosystem homeostasis. Here, we aimed to verify the occurrence of microbe-driven phenanthrene co-oxidation in the seawater surrounding the Trindade Island (Brazil). We also used Next-Generation Sequencing to evaluate the effects of aliphatic and polycyclic aromatic hydrocarbons (PAHs) on these microbial community assemblies. Microcosms containing seawater from the island enriched with either labelled (9-14C) or non-labelled phenanthrene together with hexadecane, weathered oil, fluoranthene or pyrene, and combinations of these compounds were incubated. Biodegradation of phenanthrene-9-14C was negatively affected in the presence of weathered oil and PAHs but increased in the presence of hexadecane. PAH contamination caused shifts in the seawater microbial community-from a highly diverse one dominated by Alphaproteobacteria to less diverse communities dominated by Gammaproteobacteria. Furthermore, the combination of PAHs exerted a compounded negative influence on the microbial community, reducing its diversity and thus functional capacity of the ecosystem. These results advance our understanding of bacterial community dynamics in response to contrasting qualities of hydrocarbon contamination. This understanding is fundamental in the application and monitoring of bioremediation strategies if accidents involving oil spillages occur near Trindade Island and similar ecosystems.
- MeSH
- alkany MeSH
- Alphaproteobacteria účinky léků metabolismus MeSH
- Bacteria klasifikace účinky léků genetika metabolismus MeSH
- biodegradace MeSH
- biodiverzita MeSH
- DNA bakterií genetika MeSH
- ekosystém MeSH
- fenantreny metabolismus MeSH
- Gammaproteobacteria účinky léků metabolismus MeSH
- látky znečišťující vodu MeSH
- metagenomika MeSH
- mikrobiální společenstva účinky léků genetika fyziologie MeSH
- mořská voda mikrobiologie MeSH
- ostrovy MeSH
- polycyklické aromatické uhlovodíky farmakologie MeSH
- pyreny MeSH
- RNA ribozomální 16S metabolismus MeSH
- uhlovodíky škodlivé účinky MeSH
- vysoce účinné nukleotidové sekvenování MeSH
- znečištění ropou škodlivé účinky MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Brazílie MeSH
- ostrovy MeSH
Substantial increases in cardiac output (CO), stroke volume (SV), and gastrointestinal blood flow are essential for euryhaline rainbow trout (Oncorhyncus mykiss) osmoregulation in seawater. However, the underlying hemodynamic mechanisms responsible for these changes are unknown. By examining a range of circulatory and cardiac morphological variables of seawater- and freshwater-acclimated rainbow trout, the present study revealed a significantly higher central venous pressure (CVP) in seawater-acclimated trout (~0.09 vs. -0.02 kPa). This serves to increase cardiac end-diastolic volume in seawater and explains the elevations in SV (~0.41 vs. 0.27 ml/kg) and CO (~21.5 vs. 14.2 ml·min(-1)·kg(-1)) when compared with trout in freshwater. Furthermore, these hemodynamic modifications coincided with a significant increase in the proportion of compact myocardium, which may be necessary to compensate for the increased wall tension associated with a larger stroke volume. Following a temperature increase from 10 to 16.5°C, both acclimation groups exhibited similar increases in heart rate (Q10 of ~2), but SV tended to decrease in seawater-acclimated trout despite the fact that CVP was maintained in both groups. This resulted in CO of seawater- and freshwater-acclimated trout stabilizing at a similar level after warming (~26 ml·min(-1)·kg(-1)). The consistently higher CVP of seawater-acclimated trout suggests that factors other than compromised cardiac filling constrained the SV and CO of these individuals at high temperatures. The present study highlights, for the first time, the complex interacting effects of temperature and water salinity on cardiovascular responses in a euryhaline fish species.
- MeSH
- centrální žilní tlak fyziologie MeSH
- minutový srdeční výdej fyziologie MeSH
- mořská voda * MeSH
- Oncorhynchus mykiss fyziologie MeSH
- osmoregulace fyziologie MeSH
- remodelace komor fyziologie MeSH
- tepový objem fyziologie MeSH
- tolerance k soli fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
An automatic flow-based system as a front end to liquid chromatography (LC) for on-line dynamic leaching of microplastic materials (polyethylene of medium density and poly(vinyl chloride)) with incurred phthalates and bisphenol A is herein presented. The microplastic particles were packed in a metal column holder, through which seawater was pumped continuously by resorting to advanced flow methodology. Each milliliter of the leachable (bioaccessible) fraction of chemical additives was preconcentrated on-line using a 10 mm-long octadecyl monolithic silica column placed in the sampling loop of the injection valve of a HPLC system that served concomitantly for analyte uptake and removal of the seawater matrix. After loading of the leachate fraction, the LC valve was switched to the inject position and the analytes were eluted and separated by a monolithic column (Onyx C18HD 100 × 4.6 mm) using an optimized acetonitrile/water gradient with UV detection at 240 nm. The automatic flow method including dynamic flow-through extraction, on-line sorptive preconcentration, and matrix clean-up was synchronized with the HPLC separation, which lasted ca. 9 min. The only two currently available multi-component certified reference materials (CRM) of microplastics (CRM-PE002 and CRM-PVC001) were used for method development and validation. Out of the eight regulated phthalates contained in the two CRMs, only the 2 most polar species, namely, dimethyl phthalate and diethyl phthalate as well as bisphenol A, were leached significantly by the seawater in less than 2 h, with bioaccessibility percentages of 51-100%. The leaching profiles were monitored and modeled with a first-order kinetic equation so as to determine the rate constants for desorption in a risk assessment scenario. Intermediate precision values of bioaccessibility data for three batches of CRMs were for the suite of targeted compounds ≤22%. This work for the first time reports a fully automatic flow method with infinite sink capacity (i.e., using a surplus of extracting solution) for the target species able to mimic the leaching of additives from plastic debris across the water body in marine settings under worst-case extraction conditions.
Some per- and polyfluoroalkyl substances (PFASs) have been detected ubiquitously in the environment. Owing to the polar character conferred by the presence of the carboxylic or sulfonic acid groups and their resistance to degradation, aquatic environments became their major reservoirs, including marine waters. The procedure of PFAS analysis in aqueous matrices consists usually of solid-phase extraction (SPE) followed by high-performance liquid chromatography coupled to tandem mass spectrometry. Moreover, passive sampling approach using various SPE sorbents may be applied. This study deals with the assessment of retention characteristics of a selected group of PFASs in marine water on three sorbent media widely used in SPE or passive sampling techniques. The influence of type of sorbent, matrix pH, salinity and eluent on the PFAS recovery from aquatic samples was investigated. The best overall extraction conditions were found to be at pH 8 and 50%/100% matrix seawater content using Oasis®HLB/Strata™-X as SPE sorbents and methanol as eluent. The matrix properties found to be the most appropriate for extraction of investigated PFASs from aqueous samples (i.e., pH and salinity levels) match well the natural properties of marine and brackish waters. Acid-base behavior was found to be the main driver influencing the recovery of PFASs. These research findings can be used to optimize PFAS extraction conditions from aquatic samples and also to develop efficient extraction procedures for multiresidual analyses.
- MeSH
- chemické látky znečišťující vodu analýza izolace a purifikace MeSH
- extrakce na pevné fázi metody MeSH
- fluorokarbony izolace a purifikace MeSH
- kyseliny sulfonové MeSH
- mořská voda chemie MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Publikační typ
- časopisecké články MeSH
Sulphide-driven anoxygenic photosynthesis is an ancient microbial metabolism that contributes significantly to inorganic carbon fixation in stratified, sulphidic water bodies. Methods commonly applied to quantify inorganic carbon fixation by anoxygenic phototrophs, however, cannot resolve the contributions of distinct microbial populations to the overall process. We implemented a straightforward workflow, consisting of radioisotope labelling and flow cytometric cell sorting based on the distinct autofluorescence of bacterial photopigments, to discriminate and quantify contributions of co-occurring anoxygenic phototrophic populations to in situ inorganic carbon fixation in environmental samples. This allowed us to assign 89.3% ± 7.6% of daytime inorganic carbon fixation by anoxygenic phototrophs in Lake Rogoznica (Croatia) to an abundant chemocline-dwelling population of green sulphur bacteria (dominated by Chlorobium phaeobacteroides), whereas the co-occurring purple sulphur bacteria (Halochromatium sp.) contributed only 1.8% ± 1.4%. Furthermore, we obtained two metagenome assembled genomes of green sulphur bacteria and one of a purple sulphur bacterium which provides the first genomic insights into the genus Halochromatium, confirming its high metabolic flexibility and physiological potential for mixo- and heterotrophic growth.
- MeSH
- Chlorobium izolace a purifikace metabolismus MeSH
- Chromatiaceae izolace a purifikace metabolismus MeSH
- fotosyntéza MeSH
- jezera mikrobiologie MeSH
- koloběh uhlíku MeSH
- mořská voda mikrobiologie MeSH
- síra metabolismus MeSH
- sulfidy metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Chorvatsko MeSH
Gaseous exchange fluxes of organochlorine pesticides (OCPs) across the air-water interface of the coastal East China Sea were determined in order to assess whether the contaminated plume of the Yangtze River could be an important regional source of OCPs to the atmosphere. Hexachlorocyclohexanes (HCHs), chlordane compounds (CHLs), and dichlorodiphenyltrichloroethanes (DDTs) were the most frequently detected OCPs in air and water. Air-water exchange was mainly characterized by net volatilization for all measured OCPs. The net gaseous exchange flux ranged 10-240 ng/(m2·day) for γ-HCH, 60-370 ng/(m2·day) for trans-CHL, 97-410 ng/(m2·day) for cis-CHL, and ∼0 (e.g., equilibrium) to 490 ng/(m2·day) for p,p'-DDE. We found that the plume of the large contaminated river can serve as a significant regional secondary atmospheric source of legacy contaminants released in the catchment. In particular, the sediment plume represented the relevant source of DDT compounds (especially p,p'-DDE) sustaining net degassing when clean air masses from the open ocean reached the plume area. In contrast, a mass balance showed that, for HCHs, contaminated river discharge (water and sediment) plumes were capable of sustaining volatilization throughout the year. These results demonstrate the inconsistencies in the fate of HCHs and DDTs in this large estuarine system with declining primary sources.
- MeSH
- atmosféra chemie MeSH
- chemické látky znečišťující vodu analýza MeSH
- chlorované uhlovodíky analýza MeSH
- dichlordifenyldichlorethylen analýza MeSH
- geologické sedimenty chemie MeSH
- hexachlorcyklohexan analýza MeSH
- monitorování životního prostředí metody MeSH
- mořská voda chemie MeSH
- pesticidy analýza MeSH
- řeky chemie MeSH
- vzduch * MeSH
- zeměpis MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Čína MeSH
Near-ground air (26 substances) and surface seawater (55 substances) concentrations of persistent toxic substances (PTS) were determined in July 2012 in a coordinated and coherent way around the Aegean Sea based on passive air (10 sites in 5 areas) and water (4 sites in 2 areas) sampling. The direction of air-sea exchange was determined for 18 PTS. Identical samplers were deployed at all sites and were analysed at one laboratory. hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs) as well as dichlorodiphenyltrichloroethane (DDT) and its degradation products are evenly distributed in the air of the whole region. Air concentrations of p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and o,p'-DDT and seawater concentrations of p,p'-DDE and p,p'-DDD were elevated in Thermaikos Gulf, northwestern Aegean Sea. The polychlorinated biphenyl (PCB) congener pattern in air is identical throughout the region, while polybrominated diphenylether (PBDE)patterns are obviously dissimilar between Greece and Turkey. Various pollutants, polycyclic aromatic hydrocarbons (PAHs), PCBs, DDE, and penta- and hexachlorobenzene are found close to phase equilibrium or net-volatilisational (upward flux), similarly at a remote site (on Crete) and in the more polluted Thermaikos Gulf. The results suggest that effective passive air sampling volumes may not be representative across sites when PAHs significantly partitioning to the particulate phase are included.
- MeSH
- chemické látky znečišťující vodu analýza MeSH
- DDT analýza MeSH
- dichlordifenyldichlorethylen analýza MeSH
- halogenované difenylethery analýza MeSH
- hexachlorbenzen analýza MeSH
- hexachlorcyklohexan analýza MeSH
- kvalita vody MeSH
- látky znečišťující vzduch analýza MeSH
- mořská voda chemie MeSH
- polychlorované bifenyly analýza MeSH
- polycyklické aromatické uhlovodíky analýza MeSH
- znečištění životního prostředí analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Řecko MeSH
- Turecko MeSH
Certification of trace metals in seawater certified reference materials (CRMs) NASS-7 and CASS-6 is described. At the National Research Council Canada (NRC), column separation was performed to remove the seawater matrix prior to the determination of Cd, Cr, Cu, Fe, Pb, Mn, Mo, Ni, U, V, and Zn, whereas As was directly measured in 10-fold diluted seawater samples, and B was directly measured in 200-fold diluted seawater samples. High-resolution inductively coupled plasma mass spectrometry (HR-ICPMS) was used for elemental analyses, with double isotope dilution for the accurate determination of B, Cd, Cr, Cu, Fe, Pb, Mo, Ni, U, and Zn in seawater NASS-7 and CASS-6, and standard addition calibration for As, Co, Mn, and V. In addition, all analytes were measured using standard addition calibration with triple quadrupole (QQQ)-ICPMS to provide a second set of data at NRC. Expert laboratories worldwide were invited to contribute data to the certification of trace metals in NASS-7 and CASS-6. Various analytical methods were employed by participants including column separation, co-precipitation, and simple dilution coupled to ICPMS detection or flow injection analysis coupled to chemiluminescence detection, with use of double isotope dilution calibration, matrix matching external calibration, and standard addition calibration. Results presented in this study show that majority of laboratories have demonstrated their measurement capabilities for the accurate determination of trace metals in seawater. As a result of this comparison, certified/reference values and associated uncertainties were assigned for 14 elements in seawater CRMs NASS-7 and CASS-6, suitable for the validation of methods used for seawater analysis.
- Publikační typ
- časopisecké články MeSH
OBJECTIVE: To evaluate the potential of nasal isotonic saline application to prevent reappearance of cold and flu in children during the winter. DESIGN: Prospective, multicenter, parallel-group, open, and randomized comparison. SETTING: Eight pediatric outpatient clinics. PATIENTS: A total of 401 children (aged 6-10 years) with uncomplicated cold or flu. INTERVENTIONS: We randomly assigned patients to 2 treatment groups, one with just standard medication, the other with nasal wash with a modified seawater solution (Physiomer) plus standard medication, and observed them for 12 weeks. MAIN OUTCOME MEASURES: The primary efficacy end points were nasal symptoms resolution during acute illness (visits 1 and 2). We also looked for reappearance of cold or flu, consumption of medication, complications, days off school, and reported days of illness during the following weeks when preventive potential was evaluated (visits 3 and 4). RESULTS: At visit 2, patients in the saline group achieved primary end points (measured on a 4-point numeric scale on which 1 indicated no symptoms and 4, severe symptoms) in the parameters nasal secretion and obstruction (mean scores vs nonsaline group, 1.79 vs 2.10 and 1.25 vs 1.58, respectively) (P < .05 for both). During the prevention phase (at visit 3, 8 weeks after study entry) patients in the saline group showed significantly lower scores in sore throat, cough, nasal obstruction, and secretion (P < .05 for all). By visit 3, significantly fewer children in the saline group were using antipyretics (9% vs 33%), nasal decongestants (5% vs 47%), mucolytics (10% vs 37%), and systemic antiinfectives (6% vs 21%) (P < .05 for all). During the same period children in the saline group also reported significantly fewer illness days (31% vs 75%), school absences (17% vs 35%), and complications (8% vs 32%) (P < .05 for all). Similar results were found at the final visit. CONCLUSION: Children in the saline group showed faster resolution of some nasal symptoms during acute illness and less frequent reappearance of rhinitis subsequently.
- MeSH
- analýza rozptylu MeSH
- aplikace intranazální MeSH
- chlorid sodný aplikace a dávkování MeSH
- dítě MeSH
- financování organizované MeSH
- isotonické roztoky aplikace a dávkování MeSH
- lidé MeSH
- neparametrická statistika MeSH
- prospektivní studie MeSH
- rozdělení chí kvadrát MeSH
- rýma farmakoterapie prevence a kontrola MeSH
- výsledek terapie MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- multicentrická studie MeSH
- randomizované kontrolované studie MeSH
