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1.
Ying Yong Sheng Tai Xue Bao ; 35(3): 817-826, 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38646770

RESUMO

To explore the causes of red tides in Qinhuangdao coastal water, we conducted surveys on both water quality and red tides during April to September of 2022 and analyzed the relationships between main environmental factors and red tide organisms through the factor analysis and canonical correspondence analysis. The results showed that there were eight red tides along the coast of Qinhuangdao in 2022, with a cumulative blooming area of 716.1 km2. The red tides could be divided into three kinds based on the major blooming organisms and occurrence time, Noctiluca scintillans bloom, diatom-euglena (Skeletonema costatum, Eutreptiella gymnastica, Pseudo-nitzschia spp.) bloom, and dinoflagellate (Scrippsiella trochoidea and Ceratium furca) bloom. Seasonal factor played roles mainly during July to September, while inorganic nutrients including nitrogen and phosphorus influenced the blooms mainly in April and July. The canonical correspondence analysis suggested that N. scintillans preferred low temperature, and often bloomed with high concentrations of ammonium nitrogen and dissolved inorganic phosphorus. S. costatum, E. gymnastica, and Pseudo-nitzschia spp. could tolerate broad ranges of various environmental factors, but favored high temperature and nitrogen-rich seawater. C. furca and S. trochoidea had higher survival rate and competitiveness in phosphate-poor waters. Combined the results from both analyses, we concluded that the causes for the three kinds of red tide processes in Qinhuangdao coastal areas in 2022 were different. Adequate diet algae and appropriate water temperature were important factors triggering and maintaining the N. scintillans bloom. Suitable temperature, salinity and eutrophication were the main reasons for the diatom-euglena bloom. The abundant nutrients and seawater disturbance promoted the germination of S. trochoidea cysts, while phosphorus limitation caused the blooming organism switched to C. furca and maintained the bloom hereafter.


Assuntos
Diatomáceas , Dinoflagellida , Monitoramento Ambiental , Proliferação Nociva de Algas , Água do Mar , China , Dinoflagellida/crescimento & desenvolvimento , Água do Mar/análise , Água do Mar/química , Diatomáceas/crescimento & desenvolvimento , Oceanos e Mares , Fósforo/análise , Nitrogênio/análise , Estações do Ano
2.
Environ Sci Technol ; 58(15): 6825-6834, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38567993

RESUMO

Hg(I) may control Hg redox kinetics; however, its metastable nature hinders analysis. Herein, the stability of Hg(I) during standard preparation and analysis was studied. Gravimetric analysis showed that Hg(I) was stable in its stock solution (1000 mg L-1), yet completely disproportionated when its dilute solution (10 µg L-1) was analyzed using liquid chromatography (LC)-ICPMS. The Hg(I) dimer can form through an energetically favorable comproportionation between Hg(0) and Hg(II), as supported by density functional theory calculation and traced by the rapid isotope exchange between 199Hg(0)aq and 202Hg(II). However, the separation of Hg(0) and Hg(II) (e.g., LC process) triggered its further disproportionation. Polypropylene container, increasing headspace, decreasing pH, and increasing dissolved oxygen significantly enhanced the disproportionation or redox transformations of Hg(I). Thus, using a glass container without headspace and maintaining a slightly alkaline solution are recommended for the dilute Hg(I) stabilization. Notably, we detected elevated concentrations of Hg(I) (4.4-6.1 µg L-1) in creek waters from a heavily Hg-polluted area, accounting for 54-70% of total dissolved Hg. We also verified the reductive formation of Hg(I) in Hg(II)-spiked environmental water samples, where Hg(I) can stably exist in aquatic environments for at least 24 h, especially in seawater. These findings provide mechanistic insights into the transformation of Hg(I), which are indicative of its further environmental identification.


Assuntos
Mercúrio , Poluentes Químicos da Água , Mercúrio/análise , Água do Mar/análise , Água do Mar/química , Isótopos/análise , Poluentes Químicos da Água/análise
3.
Sci Total Environ ; 922: 171103, 2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38402970

RESUMO

Temperature changes due to climate change and microplastic contamination are worldwide concerns, creating various problems in the marine environment. Therefore, this study was carried out to discover the impact of different temperatures of seawater exposed to different types of plastic materials on culture dependent bacterial responses and oxidative characteristics. Seawater was exposed to microplastics obtained from various plastic materials at different temperature (-18, +4, +20, and +35 °C) for seven days. Then microplastics were removed from the suspension and microplastic-exposed seawater samples were analyzed for bacterial activity, biofilm formation and oxidative characteristics (antioxidant, catalase, glutathione, and superoxide dismutase) using Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus. The results showed that the activity and biofilm formation of Pseudomonas aeruginosa and Staphylococcus aureus were affected through oxidative stress by catalase, glutathione, and superoxide dismutase due to the microplastic deformation by temperature changes. This study confirms that temperature changes as a result of climate change might influence microplastic degradation and their contamination impact in seawater in terms of bacterial metabolic and oxidation reactions.


Assuntos
Microplásticos , Poluentes Químicos da Água , Microplásticos/análise , Plásticos/análise , Catalase/metabolismo , Mudança Climática , Poluentes Químicos da Água/análise , Água do Mar/análise , Estresse Oxidativo , Glutationa/metabolismo , Superóxido Dismutase/metabolismo , Biofilmes
4.
Nature ; 620(7972): 104-109, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37532817

RESUMO

Iron is important in regulating the ocean carbon cycle1. Although several dissolved and particulate species participate in oceanic iron cycling, current understanding emphasizes the importance of complexation by organic ligands in stabilizing oceanic dissolved iron concentrations2-6. However, it is difficult to reconcile this view of ligands as a primary control on dissolved iron cycling with the observed size partitioning of dissolved iron species, inefficient dissolved iron regeneration at depth or the potential importance of authigenic iron phases in particulate iron observational datasets7-12. Here we present a new dissolved iron, ligand and particulate iron seasonal dataset from the Bermuda Atlantic Time-series Study (BATS) region. We find that upper-ocean dissolved iron dynamics were decoupled from those of ligands, which necessitates a process by which dissolved iron escapes ligand stabilization to generate a reservoir of authigenic iron particles that settle to depth. When this 'colloidal shunt' mechanism was implemented in a global-scale biogeochemical model, it reproduced both seasonal iron-cycle dynamics observations and independent global datasets when previous models failed13-15. Overall, we argue that the turnover of authigenic particulate iron phases must be considered alongside biological activity and ligands in controlling ocean-dissolved iron distributions and the coupling between dissolved and particulate iron pools.


Assuntos
Ferro , Minerais , Água do Mar , Ferro/análise , Ferro/química , Ferro/metabolismo , Ligantes , Minerais/análise , Minerais/química , Minerais/metabolismo , Ciclo do Carbono , Conjuntos de Dados como Assunto , Oceano Atlântico , Água do Mar/análise , Água do Mar/química , Bermudas , Fatores de Tempo , Estações do Ano , Soluções/química , Internacionalidade
5.
Sensors (Basel) ; 22(16)2022 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-36015779

RESUMO

This study is a continuation of analyses of the fluorometric index (FI), based on the fluorescence of substances of oil origin, as an indicator of oil in a seawater column. The effectiveness of the FI in the cold season (late autumn, winter and early spring) for the coastal water in the southern Baltic Sea was assessed. FI was tested for seawater polluted with a mixture of crude oils, lubricating oils and fuels. Laboratory analyses of oil-water systems for low (reaching the limit of detection) oil content in seawater were performed. The influences of the natural components of seawater that disrupt oil detection are discussed. The ability to detect oil in a seawater column regardless of the season was confirmed.


Assuntos
Água do Mar , Poluentes Químicos da Água , Monitoramento Ambiental , Estações do Ano , Água do Mar/análise , Água/análise , Poluentes Químicos da Água/análise
6.
Molecules ; 25(21)2020 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-33158094

RESUMO

The establishment and development of a set of methods of oil accurate recognition in a different environment are of great significance to the effective management of oil spill pollution. In this work, the concentration-emission matrix (CEM) is formed by introducing the concentration dimension. The principal component analysis (PCA) is applied to extract the spectral feature. The classification methods, such as Probabilistic Neural Networks (PNNs) and Genic Algorithm optimization Support Vector Machine (SVM) parameters (GA-SVM), are used for oil identification and the recognition accuracies of the two classification methods are compared. The results show that the GA-SVM combined with PCA has the highest recognition accuracy for different oils. The proposed approach has great potential in rapid and accurate oil source identification.


Assuntos
Poluição por Petróleo , Petróleo/análise , Água do Mar/análise , Máquina de Vetores de Suporte , Poluentes Químicos da Água/análise , Análise de Componente Principal , Espectroscopia de Luz Próxima ao Infravermelho
7.
Braz J Microbiol ; 51(3): 1159-1168, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32078731

RESUMO

We studied petroleum biodegradation by biostimulation by using water in oil in water (W/O/W) double emulsions. These emulsions were developed using seawater, canola oil, surfactants, and mineral salts as sources of NPK. The emulsions were used in the simulation of hydrocarbon bioremediation in oligotrophic sea water. Hydrocarbon biodegradation was evaluated by CO2 emissions from microcosms. We also evaluated the release of inorganic nutrients and the stability of the emulsion's droplets. The double emulsions improved CO2 emission from the microcosms, suggesting the increase in the hydrocarbon biodegradation. Mineral nutrients were gradually released from the emulsions supporting the hydrocarbon biodegradation. This was attributed to the formation of different diameters of droplets and therefore, varying stabilities of the droplets. Addition of the selected hydrocarbonoclastic isolates simulating bioaugmentation improved the hydrocarbon biodegradation. We conclude that the nutrient-rich W/O/W emulsion developed in this study is an effective biostimulation agent for bioremediation in oligotrophic aquatic environments.


Assuntos
Bactérias/metabolismo , Hidrocarbonetos/metabolismo , Petróleo/metabolismo , Água do Mar/microbiologia , Poluentes Químicos da Água/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biodegradação Ambiental , Emulsões/análise , Emulsões/metabolismo , Petróleo/análise , Água do Mar/análise , Poluentes Químicos da Água/análise
8.
Int J Mol Med ; 45(2): 658-668, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31894254

RESUMO

Mineral­balanced deep sea water (MBDSW), an unlimited natural sea source, has been demonstrated to minimize the risk of developing cardiovascular diseases, such as obesity, hypertension, inflammation and hyperlipidemia. This study investigated the effects of MBDSW [magnesium (Mg):calcium (Ca) ratio, 3:1] on platelet activation. MBDSW significantly inhibited the collagen­ and thrombin­induced platelet aggregation of human platelets. In collagen­induced platelets, MBDSW inhibited intracellular calcium mobilization, granule secretion [serotonin, adenosine triphosphate (ATP) and P­selectin expression] and thromboxane A2 (TXA2) production. Moreover, MBDSW markedly inhibited Akt and extracellular signal­regulated kinase (ERK) phosphorylation, but not that of c­Jun N­terminal kinase (JNK) and p38. Moreover, MBDSW phosphorylated inositol 1,4,5­triphosphate receptor (IP3R) and vasodilator­stimulated phosphoprotein (VASP), and it increased the cyclic adenosine monophosphate (cAMP) level in collagen­induced human platelets. Dipyridamole, a phosphodiesterase (PDE) inhibitor, significantly increased the cAMP level and regulated the Akt, ERK and VASP (Ser157) levels in a manner similar to that of MBDSW. In addition, LY294002, an Akt inhibitor, inhibited the phosphorylation of ERK, and U0126, an ERK inhibitor, inhibited the phosphorylation of Akt. Taken together, the results of the present investigation suggest that the inhibitory effects of MBDSW on platelet aggregation may be associated with the cross­inhibition of Akt and ERK phosphorylation. These results strongly indicate that MBDSW may have preventive or therapeutic potential for platelet aggregation­mediated diseases, such as thrombosis, atherosclerosis and myocardial infarction.


Assuntos
Águas Minerais , Inibidores da Agregação Plaquetária/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Água do Mar , Plaquetas/citologia , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Águas Minerais/análise , Inibidores da Agregação Plaquetária/análise , Proteínas Proto-Oncogênicas c-akt/metabolismo , Água do Mar/análise , Transdução de Sinais/efeitos dos fármacos
9.
Braz J Microbiol ; 51(2): 691-700, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31612432

RESUMO

The use of dispersants in marine environments is a common practice worldwide for oil spill remediation. While the effects of chemical dispersants have been extensively studied, those of biosurfactants, mainly surfactin that is considered one of the most effective surfactants produced by bacteria, have been less considered. We constructed microcosms containing marine water collected from Grumari beach (W_GB, Brazil) and from Schiermonnikoog beach (W_SI, The Netherlands) with the addition of oil (WO), Ultrasperse II plus oil (WOS), surfactin plus oil (WOB), and both dispersants (WS or WB) individually. In these treatments, the composition of bacterial communities and their predictive biodegradation potential were determined over time. High-throughput sequencing of the rrs gene encoding bacterial 16S rRNA revealed that Bacteroidetes (Flavobacteria class) and Proteobacteria (mainly Gammaproteobacteria and Alphaproteobacteria classes) were the most abundant phyla found among the W_GB and W_SI microbiomes, and the relative abundance of the bacterial types in the different microcosms varied based on the treatment applied. Non-metrical multidimensional scaling (NMDS) revealed a clear clustering based on the addition of oil and on the dispersant type added to the GB or SI microcosms, i.e., WB and WOB were separated from WS and WOS in both marine ecosystems studied. The potential presence of diverse enzymes involved in oil degradation was indicated by predictive bacterial metagenome reconstruction. The abundance of predicted genes for degradation of petroleum hydrocarbons increased more in surfactin-treated microcosms than those treated with Ultrasperse II, mainly in the marine water samples from Grumari beach.


Assuntos
Microbiota , Água do Mar/microbiologia , Tensoativos/metabolismo , Microbiologia da Água , Poluentes Químicos da Água/metabolismo , Bactérias/classificação , Bactérias/metabolismo , Biodegradação Ambiental , Brasil , Metagenoma , Petróleo/metabolismo , Poluição por Petróleo , Água do Mar/análise , Tensoativos/classificação
10.
Mar Pollut Bull ; 143: 125-133, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31789147

RESUMO

Current study aimed to evaluate the microplastics abundance in the surface waters of Chabahar Bay for the first time. 21 neuston net water samples were collected from 7 stations. Microplastics were visually counted by stereomicroscope, sorted into 4 size categories, 4 shape categories, and identified by ATR-FTIR spectroscopy. Density of microplastics varied from 0.07 ±â€¯0.03 to 1.14 ±â€¯0.27 with an average density of 0.49 ±â€¯0.43 particle·m-3. Microplastics were mostly found in the shape of fibers. 69% of analyzed particles were polyethylene and polypropylene. Main colors of the collected microplastics were white, blue and red. The results showed that the largest number of microplastics was found at station near populated area. Therefore, it can be concluded that, there is a pressing-need to investigate the distribution of microplastics in sediments and biota of this Bay as well as their effects on marine life and human health.


Assuntos
Microplásticos/análise , Água do Mar/análise , Poluentes Químicos da Água/análise , Baías , Cor , Monitoramento Ambiental/métodos , Irã (Geográfico) , Microplásticos/química , Polietileno/análise , Polipropilenos/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/química
11.
Nat Commun ; 10(1): 5261, 2019 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-31748607

RESUMO

Marine phytoplankton growth at high latitudes is extensively limited by iron availability. Icebergs are a vector transporting the bioessential micronutrient iron into polar oceans. Therefore, increasing iceberg fluxes due to global warming have the potential to increase marine productivity and carbon export, creating a negative climate feedback. However, the magnitude of the iceberg iron flux, the subsequent fertilization effect and the resultant carbon export have not been quantified. Using a global analysis of iceberg samples, we reveal that iceberg iron concentrations vary over 6 orders of magnitude. Our results demonstrate that, whilst icebergs are the largest source of iron to the polar oceans, the heterogeneous iron distribution within ice moderates iron delivery to offshore waters and likely also affects the subsequent ocean iron enrichment. Future marine productivity may therefore be not only sensitive to increasing total iceberg fluxes, but also to changing iceberg properties, internal sediment distribution and melt dynamics.


Assuntos
Camada de Gelo/química , Ferro/análise , Regiões Antárticas , Regiões Árticas , Argentina , Carbono/metabolismo , Chile , Congelamento , Sedimentos Geológicos/análise , Sedimentos Geológicos/química , Aquecimento Global , Groenlândia , Islândia , Ferro/metabolismo , Oceanos e Mares , Fitoplâncton/metabolismo , Água do Mar/análise , Água do Mar/química , Svalbard
12.
Proc Natl Acad Sci U S A ; 116(45): 22505-22511, 2019 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-31591189

RESUMO

Glycerol dibiphytanyl glycerol tetraethers (GDGTs) are distinctive archaeal membrane-spanning lipids with up to eight cyclopentane rings and/or one cyclohexane ring. The number of rings added to the GDGT core structure can vary as a function of environmental conditions, such as changes in growth temperature. This physiological response enables cyclic GDGTs preserved in sediments to be employed as proxies for reconstructing past global and regional temperatures and to provide fundamental insights into ancient climate variability. Yet, confidence in GDGT-based paleotemperature proxies is hindered by uncertainty concerning the archaeal communities contributing to GDGT pools in modern environments and ambiguity in the environmental and physiological factors that affect GDGT cyclization in extant archaea. To properly constrain these uncertainties, a comprehensive understanding of GDGT biosynthesis is required. Here, we identify 2 GDGT ring synthases, GrsA and GrsB, essential for GDGT ring formation in Sulfolobus acidocaldarius Both proteins are radical S-adenosylmethionine proteins, indicating that GDGT cyclization occurs through a free radical mechanism. In addition, we demonstrate that GrsA introduces rings specifically at the C-7 position of the core GDGT lipid, while GrsB cyclizes at the C-3 position, suggesting that cyclization patterns are differentially controlled by 2 separate enzymes and potentially influenced by distinct environmental factors. Finally, phylogenetic analyses of the Grs proteins reveal that marine Thaumarchaeota, and not Euryarchaeota, are the dominant source of cyclized GDGTs in open ocean settings, addressing a major source of uncertainty in GDGT-based paleotemperature proxy applications.


Assuntos
Proteínas Arqueais/metabolismo , Diglicerídeos/biossíntese , Lipídeos de Membrana/biossíntese , Água do Mar/análise , Sulfolobus acidocaldarius/metabolismo , Archaea/classificação , Archaea/genética , Archaea/metabolismo , Proteínas Arqueais/genética , Ciclização , Diglicerídeos/química , Lipídeos de Membrana/química , Oceanos e Mares , Filogenia , Sulfolobus acidocaldarius/química
13.
Mar Pollut Bull ; 146: 831-837, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426225

RESUMO

An interlaboratory comparison exercise was conducted to assess the consistency of microplastic quantification across several laboratories. The test samples were prepared by mixing one liter seawater free of plastics, microplastics made from polypropylene, high- and low-density polyethylene, and artificial particles in two plastic bottles, and analyzed concurrently in 12 experienced laboratories around the world. The minimum requirements to quantify microplastics were examined by comparing actual numbers of microplastics in these sample bottles with numbers measured in each laboratory. The uncertainty was due to pervasive errors derived from inaccuracies in measuring sizes and/or misidentification of microplastics, including both false recognition and overlooking. The size distribution of microplastics should be smoothed using a running mean with a length of >0.5 mm to reduce uncertainty to less than ±20%. The number of microplastics <1 mm was underestimated by 20% even when using the best practice for measuring microplastics in laboratories.


Assuntos
Laboratórios/normas , Plásticos/análise , Monitoramento Ambiental , Polietileno/análise , Polipropilenos/análise , Água do Mar/análise
14.
Mikrochim Acta ; 186(8): 537, 2019 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-31317277

RESUMO

A capillary monolith consisting of poly[N-(4-vinyl)-benzyl iminodiacetic acid-co-divinylbenzene-co-N,N'-methylene bisacrylamide), referred to as poly(VBIDA-DVB-Bis), has been prepared. It is shown to be an efficient sorbent for the enrichment of Co(II) and Cd(II). The two ions are completely retained by the monolith in the pH range from 4.0 to 9.0. The breakthrough curve tests were adopted to evaluate the adsorption performance of the monolith towards Co(II) and Cd(II). A dose-response model was used to describe the breakthrough curves of the two ions at different initial concentrations. The adsorption capacities for Co(II) and Cd(II) are 1.54 and 1.73 mg·m-1 at a concentration level of 2.5 mg·L-1, respectively. The enrichment factor is 100, and the required sample volume is 5 mL. Following elution of the two ions with 0.5 M HNO3, they were quantified by ICP-MS. The limits of detection in a 1 mL sample are 0.35 ng·L-1 for Co(II) and 0.44 ng·L-1 for Cd(II). The method was applied to the determination of Co(II) and Cd(II) in spiked rice, human urine and seawater samples. Graphical abstract Schematic representation of a monolithic copolymer prepared from N-(4-vinyl)-benzyl iminodiacetic acid (VBIDA), divinylbenzene (DVB) and N,N'-methylene bisacrylamide (Bis) and its application for selective capturing of cadmium(II) and cobalt(II) from complex sample matrices prior to their determination by ICP-MS.


Assuntos
Acrilamidas/química , Cádmio/análise , Cobalto/análise , Iminoácidos/química , Polímeros/química , Compostos de Vinila/química , Adsorção , Cádmio/química , Cádmio/urina , Cobalto/química , Cobalto/urina , Humanos , Espectrometria de Massas , Oryza/química , Água do Mar/análise
15.
Chemosphere ; 235: 194-204, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31255760

RESUMO

Ballast water managements systems (BWMS) installed on vessels may use active substances to inactivate organisms. This paper provides new insights in the global issue of noxious disinfection by-products (DBP) discharge with ballast water, and the related risk assessment for human health. The GESAMP ballast water working group plays a role in the certification process of BWMS that make use of active substances evaluating potential negative effects. We analyzed all BWMS that passed GESAMP final approval over a decade until 2017 providing an overview of chemicals in the discharged ballast water generated by BWMS. We used these data to calculate the chemical load humans may be exposed to for two different commercial ports (Koper, Slovenia and Hamburg, Germany). None of the chemicals in this study reached levels of concern that would indicate a risk for humans after exposure to chemicals present in the discharged ballast water. Nevertheless, although this exposure only adds to a lesser degree to the overall exposure to disinfection by-products, some chemicals, such as tribromomethane, have carcinogenic properties. In case studies we show which chemicals have the largest contribution to the aggregated exposure of humans. We note that tribromomethane, despite its low bio-concentration factor (BCF), may accumulate in fat, when fish are continuously exposed to DBPs during low-level chlorination. Since this figure would give a higher value for the internal dose for tribromomethane from seafood consumption than the current BCF in the GISIS database, the calculated value may underestimate the contribution of tribromomethane, and possibly also other DBPs.


Assuntos
Desinfetantes/toxicidade , Exposição Ambiental/análise , Medição de Risco/métodos , Água do Mar/análise , Navios , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/toxicidade , Animais , Desinfetantes/análise , Desinfecção/métodos , Exposição Ambiental/efeitos adversos , Peixes , Alemanha , Halogenação , Humanos , Água do Mar/química , Eslovênia , Poluentes Químicos da Água/análise
16.
J Environ Radioact ; 204: 66-75, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30986717

RESUMO

To analyze plutonium (Pu) in open ocean waters can be challenging due to the low seawater concentrations. In this study we compared two techniques for Pu determination, one in-situ MnO2 cartridge system and the more commonly used MnO2 precipitation technique. During the pre-pilot GEOTRACES cruise ANT XXX-1 (2005) we tested MnO2 cartridges for the pre-concentration of Pu from seawater at 19 sampling stations on a transect in the southeastern Atlantic Ocean between Vigo (Spain) and Cape Town (South Africa). Our in-situ sampling setup consisted of one particle cartridge followed by three MnO2 cartridges in a series. Through the system we pumped between 956 and 2700 l of surface seawater with a flow rate between 1.6 and 5.2 l/min. We found that the adsorption efficiency of a single MnO2 cartridge to adsorb Pu was rather constant and on average a 58 ±â€¯7%. The adsorption efficiency was also found to be independent of seawater: temperature in the range of 18.3-29.2 °C, salinity range 34.2-37.1‰, and conductivity in the range of 46.8-58.4 mS/cm. In parallel with the in-situ sampling, discrete surface water samples between 259 and 281 l were taken and Pu was pre-concentrated using the MnO2 precipitation method. We find a good agreement between the Pu concentrations determined with the two different techniques. The in-situ pre-concentration technique requires more radiochemical work in the laboratory but has the advantage that large seawater volumes can be sampled without the necessity for radiochemical processing on-board the ship. The much larger volumes sampled with the in-situ technique compared with the precipitation technique, enables accurate determination of Pu-isotopic ratios with a low relative standard deviation. We have shown in this study that in-situ MnO2 cartridge technique can be used in a reliable way for the determination of dissolved Pu seawater concentration in open ocean waters.


Assuntos
Compostos de Manganês/química , Óxidos/química , Plutônio/análise , Monitoramento de Radiação/métodos , Água do Mar/análise , Poluentes Radioativos da Água/análise , Oceano Atlântico , Precipitação Química
17.
Sci Total Environ ; 667: 1-8, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30825816

RESUMO

Microplastic contamination in the ocean has emerged as an environmental issue of global importance. The most effective strategy to control microplastic pollution is to reduce the terrestrial input, but severe weather conditions make it difficult. This study investigated microplastic abundance and characteristics in the seawater, sediments, and cultured oysters (Crassostrea gigas) of Sanggou Bay (China) before and after two typhoons with an average rainfall of 19.2 mm/d over 8 days. Prior to the typhoons, microplastic levels in the seawater, sediment, and oysters were 63.6 ±â€¯37.4 items/L, 2178 ±â€¯369 items/kg, and 41.0 ±â€¯15.5 items/individual, with fibers being the predominant shape. Typhoons increased the average concentrations of microplastics in the seawater and sediments by approximately 40%, and the proportions of fragments, spherules, and granules in the sediments increased by 9.6%, 4.0%, and 4.3%, respectively. The majority of microplastics in seawater, sediments, and oysters collected before the typhoons could be grouped into sizes of 0.1-0.5 mm (36.7%), 0.05-0.1 mm (42.6%), and 0.1-0.5 mm (47.1%), respectively. After the typhoons, the most abundant size classes of microplastics in the three environmental compartments were 0.05-0.1 mm (39.2%) for seawater, 0.1-0.5 mm (37.1%) for sediments, and 0.05-0.1 mm (29.9%) for oysters. The typhoons also altered color distribution of microplastics and increased the proportions of polypropylene, polystyrene, and polyethylene terephthalate in seawater. Scanning electron microscopy/energy dispersive spectroscopy showed that organic matter and heavy metals were present on the microplastics collected from oysters. Our results suggest that weather conditions should be considered when investigating marine microplastics.


Assuntos
Tempestades Ciclônicas , Monitoramento Ambiental , Sedimentos Geológicos/análise , Plásticos/análise , Alimentos Marinhos/análise , Água do Mar/análise , Poluentes Químicos da Água/análise , Animais , Baías , China , Crassostrea/metabolismo , Plásticos/metabolismo , Poluentes Químicos da Água/metabolismo
18.
Sci Total Environ ; 666: 743-758, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-30812008

RESUMO

Petroleum has been the world's major source of energy since the middle of the twentieth century, leading to positive changes but also social, political, and environmental problems worldwide. Oil contamination affects all ecosystems, and the remediation of polluted sites using environmentally friendly strategies is crucial. Here, we report an analysis of the patent documents of potential petroleum bioremediation techniques that use microbes to clean seawater. The patent search was performed using Orbit Intelligence®, SciFinder® and the Derwent World Patents Index®. A group of 500 patent documents were validated according to the search objective and carefully studied. Increases in patent deposits coincide with periods following widely reported oil spills, suggesting a relationship between media disclosure and stimulation of innovation activities. China leads the list of countries with patent applications in bioremediation with 152 deposits, followed by Russia with 133 and the US with 48. These three countries have completely different temporal deposit profiles, influenced by their historical, political, and economic scenarios. A total of 368 patents described degradation of the oil compounds exclusively by bacteria, 24 by fungi and yeasts, 1 by Archaea, 1 using a microalgal strain, and 32 by mixed consortia. The leading microbial genera found in the patents are Pseudomonas (114 patents), Bacillus (75), and Rhodococcus (60). In the top-10 list of microbial strains mostly cited/claimed, no genera are obligate hydrocarbonoclastic bacteria. This fact, together with the broad pattern found in the main International Patent Classification (IPC) codes, suggest that most of the documents are general bioremediation approaches and not focused on oil-polluted seawater. This work highlights the importance of stimulating the development of innovative environmentally friendly strategies focused on the degradation of oil hydrocarbons in marine ecosystems.


Assuntos
Recuperação e Remediação Ambiental/métodos , Patentes como Assunto/estatística & dados numéricos , Poluição por Petróleo , Água do Mar/análise , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental
19.
Photochem Photobiol Sci ; 18(3): 681-716, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30810560

RESUMO

Exposure of plants and animals to ultraviolet-B radiation (UV-B; 280-315 nm) is modified by stratospheric ozone dynamics and climate change. Even though stabilisation and projected recovery of stratospheric ozone is expected to curtail future increases in UV-B radiation at the Earth's surface, on-going changes in climate are increasingly exposing plants and animals to novel combinations of UV-B radiation and other climate change factors (e.g., ultraviolet-A and visible radiation, water availability, temperature and elevated carbon dioxide). Climate change is also shifting vegetation cover, geographic ranges of species, and seasonal timing of development, which further modifies exposure to UV-B radiation. Since our last assessment, there has been increased understanding of the underlying mechanisms by which plants perceive UV-B radiation, eliciting changes in growth, development and tolerances of abiotic and biotic factors. However, major questions remain on how UV-B radiation is interacting with other climate change factors to modify the production and quality of crops, as well as important ecosystem processes such as plant and animal competition, pest-pathogen interactions, and the decomposition of dead plant matter (litter). In addition, stratospheric ozone depletion is directly contributing to climate change in the southern hemisphere, such that terrestrial ecosystems in this region are being exposed to altered patterns of precipitation, temperature and fire regimes as well as UV-B radiation. These ozone-driven changes in climate have been implicated in both increases and reductions in the growth, survival and reproduction of plants and animals in Antarctica, South America and New Zealand. In this assessment, we summarise advances in our knowledge of these and other linkages and effects, and identify uncertainties and knowledge gaps that limit our ability to fully evaluate the ecological consequences of these environmental changes on terrestrial ecosystems.


Assuntos
Mudança Climática , Ozônio Estratosférico/análise , Raios Ultravioleta , Animais , Dióxido de Carbono/análise , Ecossistema , Poluentes Ambientais/análise , Água Doce/análise , Aquecimento Global , Proliferação Nociva de Algas/efeitos da radiação , Luz , Modelos Químicos , Recursos Naturais , Fotólise/efeitos da radiação , Água do Mar/análise
20.
Sci Total Environ ; 656: 946-951, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30625680

RESUMO

Mariculture activities and river inputs can lead to pollution of micropollutants (e.g., antibiotics and pesticides) in coastal seawater which is the base of the most dynamic ecosystems due to its hosting some of the highest biodiversity and biological production in the world. It is thus of importance to investigate the occurrence and risks of organic micropollutants in coastal waters. In this study, 13 antibiotics and 15 pesticides were screened in coastal waters around the Liaodong Peninsula, China. Among the targets, thirteen were detected with concentrations up to 64.8 ng L-1. Simazine, atrazine and triadimenol were found to be the predominant pesticides with detection frequencies of 100%, and sulfamethoxazole was the predominant antibiotic with a detection frequency of 62.5%. The total level of the pollutants in the Bohai Sea was generally higher than that in the Yellow Sea, and a seaward decreasing trend of the pollutants was observed. Terrestrial inputs and mariculture were distinguished as main pollution sources by principal component analysis. Finally, ecological risk quotients were calculated and atrazine and acetochlor showed relatively higher risks to aquatic organisms.


Assuntos
Antibacterianos/análise , Monitoramento Ambiental , Praguicidas/análise , Água do Mar/análise , Poluentes Químicos da Água/análise , Antibacterianos/efeitos adversos , Organismos Aquáticos/efeitos dos fármacos , China , Praguicidas/efeitos adversos , Medição de Risco , Poluentes Químicos da Água/efeitos adversos
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