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The use of surface-enhanced Raman scattering (SERS) for detection of PAHs in the Gulf of Gdańsk (Baltic Sea) Полный текст
2012
(Heinz-Detlef),
A field operable surface enhanced Raman scattering (SERS) sensor system was applied for the first time under real conditions for the detection of polycyclic aromatic hydrocarbons (PAHs) as markers for petroleum hydrocarbons in the Gulf of Gdańsk (Baltic Sea). At six stations, seawater samples were taken, and the sensor system was applied in situ simultaneously. These measurements were compared to the results of conventional GC/MS laboratory analysis of the PAH concentrations in the seawater samples. For a PAH concentration above 150ng(12PAH)l⁻¹, there was agreement between the SERS sensor and the GC/MS determinations. A standard addition experiment yielded a PAH concentration of 900ngl⁻¹ at the Gdańsk Harbor, which was of the same order as the GC/MS determinations of 12PAHs (200ng(12PAH)l⁻¹). The high SERS detection limit for seawater samples is explained by the competition for PAHs between the sensor membrane and particulate matter surfaces. Thus, the SERS sensor can be applied, e.g., as a non-quantitative alarm sensor for relatively high PAH concentrations in heavily polluted waters. The spectral unmixing procedure applied for Gdańsk Harbor water confirmed the presence of phenanthrene at the highest concentration ([Phe]=140ngl⁻¹) and of Chr (2.7ngl⁻¹), but it did not detect the other PAHs present in the Gdańsk Harbor water, as determined by GC/MS. When compared to the past literature and databases, the SERS spectra indicated the presence of a mixture of molecules consisting of carotenoids, n-alkanes, amines or fatty acids, and benzimidazoles at the coastal station ZN2. The spectra in the offshore direction indicated carboxylic acids. Interpretation of the farthest offshore in situ SERS measurements is difficult, principally due to the limited availability of reference spectra. The detection of the lower PAH concentrations commonly found in Baltic coastal water needs further research and development to obtain better sensitivity of the SERS sensor. However, the high analytical specificity of the SERS sensor also allows the detection of other chemical species that require the development of a SERS/Raman library for specific in situ spectral interpretation.
Показать больше [+] Меньше [-]Physical and chemical control of the phytoplankton of Ahe lagoon, French Polynesia Полный текст
2012
The environmental characteristics of Ahe deep lagoon (Tuamotu Archipelago, French Polynesia) were studied over 3years with the aim of explaining the spatial and temporal variability of the natural food available for pearl oysters with a special focus on phytoplankton biomass and global photosynthesis/respiration ratio of the lagoon. Chlorophyll averaged 0.34±0.01μgL⁻¹ and our findings did not confirm increased phytoplankton biomass in deep lagoonal waters. Phytoplankton production appears to be limited firstly by nitrogen and respiratory processes overpass photosynthetic processes at least in the north-eastern edge of the atoll. Grazing by pearl oysters in culture seems to decrease the POC concentration but not the phytoplankton biomass. Oysters graze mainly on non chlorophyllian particles.
Показать больше [+] Меньше [-]Evaluation of the partial renewal of in situ phytoplankton microcosms and application to the impact assessment of bentazon and dimethenamid Полный текст
2012
de la Broise, Denis | Stachowski-Haberkorn, Sabine
Evaluation of the partial renewal of in situ phytoplankton microcosms and application to the impact assessment of bentazon and dimethenamid Полный текст
2012
de la Broise, Denis | Stachowski-Haberkorn, Sabine
Microcosms, each consisting of 2L natural surface seawater maintained in 2.3-L glass bottles, were immersed at a depth of 6m. The renewal of 10% of microcosm volumes was carried out every other day. Phytoplankton-containing seawater was used for renewal (previously filtered through 25-, 50- or 200-μm cut-off). Phytoplankton community pigment analysis (by HPLC) and flow cytometry analysis were performed. After 13days, data exhibited phytoplankton characteristics in microcosms in the same range as that of the natural surrounding sea water over the same period. Furthermore, in these microcosms, a negative correlation was observed between the filtration cut-off used for renewal water, and the total cell count. Herbicides were tested as commercial mixtures at 1, 10 and 100μgL⁻¹ active substance. Both Frontier® (dimethenamid) and Basamais® (bentazon) induced significant modifications of the phytoplankton populations at every concentration tested. Such results suggest a possible disturbance in polluted coastal areas.
Показать больше [+] Меньше [-]Evaluation of the partial renewal of in situ phytoplankton microcosms and application to the impact assessment of bentazon and dimethenamid Полный текст
2012
De La Broise, Denis | Stachowski-haberkorn, Sabine
Microcosms, each consisting of 2 L natural surface seawater maintained in 2.3-L glass bottles, were immersed at a depth of 6 metres. The renewal of ten percent of microcosm volumes was carried out every other day. Phytoplankton-containing seawater was used for renewal (previously filtered through 25-, 50- or 200-μm cut-off). Phytoplankton community pigment analysis (by HPLC) and flow cytometry analysis were performed. After 13 days, data exhibited phytoplankton characteristics in microcosms in the same range as that of the natural surrounding sea water over the same period. Furthermore, in these microcosms, a negative correlation was observed between the filtration cut-off used for renewal water, and the eukaryote cell count. Herbicides were tested as commercial mixtures at 1, 10 and 100 μg.L-1 active principal. Both Frontier® (dimethenamid) and Basamais® (bentazon) induced significant modifications of the phytoplankton populations at every concentration tested. Such results suggest a possible disturbance in polluted coastal areas.
Показать больше [+] Меньше [-]Geochemistry of the northern Cyprus (NE Mediterranean) shelf sediments: Implications for anthropogenic and lithogenic impact Полный текст
2012
Duman, Muhammet | Kucuksezgin, Filiz | Atalar, Muge | Akcali, Baris
The concentrations of heavy metals and organic carbon in sediment were determined to evaluate spatial distributions from the three different regions of Cilician basin (Eastern Mediterranean) in 2011. The ranges of Cu, Pb, Zn, Ni, Co, Mn, Cr, As, Fe and organic carbon contents of sediments from the study area were 1.6–74, 1.6–9.2, 5.0–78, 6.6–114, 1.6–17, 141–1241, 9.0–46, 3.3–55.4, 1800–84400mgkg⁻¹ and 0.99–1.66%, respectively. The concentrations of Pb, Zn, Co, Cr, Al were lower than those average crustal values, which indicated that there were no major sources of pollution for these elements. The results showed that the sediments of northern, eastern and western shelf were polluted with As, Ni and Mn, As and Cu, Fe, respectively. The contamination factor of Cu in the western and As were found to be of moderate contamination in the eastern and northern parts of the study area. Metal levels were evaluated in sediments in accordance with the numerical SQG of the USEPA.
Показать больше [+] Меньше [-]Use of species sensitivity distributions to predict no-effect concentrations of an antifouling biocide, pyridine triphenylborane, for marine organisms Полный текст
2012
Mochida, Kazuhiko | Onduka, Toshimitsu | Amano, Haruna | Ito, Mana | Ito, Katsutoshi | Tanaka, Hiroyuki | Fujii, Kazunori
We used species sensitivity distributions (SSDs) and a Bayesian statistical model to carry out a primary risk assessment for pyridine triphenylborane (PTPB) in Hiroshima Bay, Japan. We used SSDs derived from toxicity values, such as EC₅₀ and LC₅₀, obtained from this study and previous work to calculate hazardous concentrations that should protect 95% and 99% of species (HC₅ and HC₁) and demonstrated that the medians of the HC₅ and HC₁ were 0.78 and 0.17μg/L, respectively. We also used liquid chromatography/mass spectrometry to investigate the occurrence of PTPB in seawater from several coastal sites of Hiroshima Bay and detected PTPB at concentrations of 4.8–21pg/L. Comparison of environmental concentrations to the HC values suggests that the current ecological risk posed by PTPB in Hiroshima Bay is low. This is the first report of the detection of PTPB in the natural marine environment.
Показать больше [+] Меньше [-]Evaluation of spatial and temporal variations of inorganic nutrient species in the eastern Aegean Sea waters Полный текст
2012
Aydin-Onen, Sinem | Kocak, Ferah | Kucuksezgin, Filiz
In this study, the state of the five stations’ quality was assessed on the basis of determination of temporal and spatial variability of nutrients with physicochemical variables. Besides this, organic matter of sediment, secchi disc depth and suspended solids were also determined. The samples were collected seasonally from different areas such as harbor and important touristic marinas along the eastern Aegean during June 2008–2009. As a result, the nutrients ranged between NH₄: 0.10–25.6, NO₂: 0.01–1.5, NO₃: 0.19–7.0, o.PO₄: 0.17–6.8, TPO₄: 0.32–9.6 and Si: 0.30–13.8μM, respectively. Precipitation leads to large changes in temperature, salinity, dissolved oxygen and nutrients. The highest nutrient values in this study were observed during the rainy season except o.PO₄-P and TPO₄-P. However, the physico-chemical variables have exhibited considerable temporal variations while nutrients showed spatial differences. The relatively high nutrient increase in the sampling stations coupled with surface runoff events during rainy period and pollution arising from both point and non-point sources.
Показать больше [+] Меньше [-]Bloom forming and toxic phytoplankton in transitional and coastal waters of Cantabria region coast (Southeastern Bay of Biscay, Spain) Полный текст
2012
Seoane, Sergio | Puente, Araceli | Guinda, Xabier | Juanes, Jose Antonio
Phytoplankton monitoring has extended to practically all the regions of the European coast due to the implementation of the European Water Framework Directive. In this way, the study of phytoplankton taxonomic composition and dynamic is being performed in many areas poorly studied or not studied before. During the last years, a monitoring programme has been carried out at the coast of Cantabria region (SE Bay of Biscay); the presence of some potentially toxic and bloom forming species (>7.5×10⁵cells per litre) has been observed. Diatoms and cryptophytes are the main blooming taxa in this region in the majority of the estuaries and in some of the coastal sites. All estuaries and coastal stations showed at least one potentially toxic species, being the dinoflagellates the group with the highest number of taxa observed. The potentially toxic species found in highest concentrations were the genera Pseudo-nitzschia and Chrysochromulina.
Показать больше [+] Меньше [-]Local scale marine modelling of Fukushima releases. Assessment of water and sediment contamination and sensitivity to water circulation description Полный текст
2012
The dispersion of ¹³⁷Cs released from Fukushima nuclear power plant to the sea after the March 11th 2011 tsunami has been studied using numerical models. The 3D dispersion model consists of an advection/diffusion equation with terms describing uptake/release reactions between water and seabed sediments. The dispersion model has been fed with daily currents provided by HYCOM and JCOPE2 ocean models. Seabed sediment ¹³⁷Cs patterns obtained using both current data set have been compared. The impact of tides and of atmospheric deposition has been evaluated as well. It has been also found that a 2-step kinetic model (two consecutive reversible reactions) for describing water/sediment interactions produces better results than a 1-step model (one single reversible reaction).
Показать больше [+] Меньше [-]Provenance of Corexit-related chemical constituents found in nearshore and inland Gulf Coast waters Полный текст
2012
The dispersants Corexit 9527 and Corexit 9500 were extensively used during the response to the Deepwater Horizon accident in 2010. In addition to the monitoring programs established by federal and state governments, local communities also conducted studies to determine if chemical constituents from these dispersants impacted nearshore and inland waters. One community (the City of Orange Beach, Alabama) collected water samples between September, 2010 and January, 2011, and found the dispersant-related chemicals propylene glycol, 2-butoxyethanol, and dioctyl sodium sulfosuccinate at nearshore and inland water sampling sites. In this paper, we examine their dataset in an attempt to discern the origin of these chemicals. Our assessment indicates that these compounds are unlikely to be present as a result of the use of Corexit dispersants; rather, they are likely related to point and non-point source stormwater discharge.
Показать больше [+] Меньше [-]Thermal treatment as a method to control transfers of invasive biofouling species via vessel sea chests Полный текст
2012
Piola, Richard F. | Hopkins, Grant A.
This study examined the efficacy of heated seawater for the treatment and remediation of fouled vessel sea chest habitats. In laboratory trials, three temperature regimes (37.5°C for 60min, 40°C for 30min and 42.5°C for 20min) were tested on a range of temperate taxa commonly found in sea chests. Field validation trials further assessed the efficacy of heat treatment within a replica sea chest environment. During laboratory trials, 100% mortality was achieved across all three treatments for the majority of taxa; the exceptions being the barnacle Elminius modestus and the oyster Crassostrea gigas. Temperature tolerance limits observed in the laboratory were successfully replicated under simulated sea chest conditions; however, a failure to achieve even heat distribution was an obstacle to achieving uniform mortality. This study provides guidance on the temperature/exposure parameters required for vessels plying temperate latitudes, and demonstrates that heated seawater has potential for controlling biofouling in vessel sea chests.
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