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Validation trials of a shipboard filter skid (p3SFS) demonstrate its utility for collecting living zooplankton 全文
2014
Drake, Lisa A. | Moser, Cameron S. | Robbins-Wamsley, Stephanie H. | Riley, Scott C. | Wier, Timothy P. | Grant, Jonathan F. | Herring, Penny R. | First, Matthew R.
Relatively large volumes of water—on the order of cubic meters—must be sampled and analyzed to generate statistically valid estimates of sparsely concentrated organisms, such as in treated ballast water. To this end, a third prototype of a shipboard filter skid (p3SFS) was designed and constructed. It consisted of two housings (each containing a 35μm mesh filter bag) and its own pump and computer controller. Additionally, the skid had a drip sampler, which collected a small volume (∼10L) of whole (unfiltered) water immediately upstream of the housings. Validation of the p3SFS occurred in two segments: (1) land-based trials, in which the collection of organisms ⩾50μm (nominally zooplankton) by the p3SFS was compared to a plankton net, and (2) shipboard trials, in which ballast water was sampled aboard a ship. In both types of trials, the data collected showed the filter skid to be an appropriate flow-through sampling device.
显示更多 [+] 显示较少 [-]Revisiting methods for the determination of bioavailable metals in coastal sediments 全文
2014
Peña-Icart, Mirella | Mendiguchía, Carolina | Villanueva-Tagle, Margarita E. | Pomares-Alfonso, Mario S. | Moreno, Carlos
A simple methodology for the determination of bioavailability of fourteen metals in coastal sediments has been developed by simulating the conditions of digestive process of marine fishes. With this aim, a representative sediment composite sample was treated with hydrochloric acid solutions at different pH values, temperatures and contact times, in the presence and absence of Pepsin and Trypsin. The addition of Pepsin and Trypsin did not affect the extraction of most elements. As a result of the present study, the digestion with a hydrochloric acid solution at pH 1, 40°C and 12h is proposed. Adjustments of the temperature and time reaction could be made according to the specific ecosystem under study. The amount of metal extracted by other methods based on acetic acid was lower than that extracted by HCl treatment proposed.
显示更多 [+] 显示较少 [-]Prevalence of marine debris in marine birds from the North Atlantic 全文
2014
Provencher, Jennifer F. | Bond, Alexander L. | Hedd, April | Montevecchi, William A. | Muzaffar, Sabir Bin | Courchesne, Sarah J. | Gilchrist, H Grant | Jamieson, Sarah E. | Merkel, Flemming R. | Falk, Knud | Durinck, Jan | Mallory, Mark L.
Marine birds have been found to ingest plastic debris in many of the world’s oceans. Plastic accumulation data from necropsies findings and regurgitation studies are presented on 13 species of marine birds in the North Atlantic, from Georgia, USA to Nunavut, Canada and east to southwest Greenland and the Norwegian Sea. Of the species examined, the two surface plungers (great shearwaters Puffinus gravis; northern fulmars Fulmarus glacialis) had the highest prevalence of ingested plastic (71% and 51%, respectively). Great shearwaters also had the most pieces of plastics in their stomachs, with some individuals containing as many of 36 items. Seven species contained no evidence of plastic debris. Reporting of baseline data as done here is needed to ensure that data are available for marine birds over time and space scales in which we see changes in historical debris patterns in marine environments (i.e. decades) and among oceanographic regions.
显示更多 [+] 显示较少 [-]XRF scanners as a quick screening tool for detecting toxic pollutant elements in sediments from Marín harbour in the Ría de Pontevedra (NW Spain) 全文
2014
Rodríguez-Germade, I. | Rubio, B. | Rey, D.
X-ray fluorescence scanners, such as the Itrax™ Core Scanner (Itrax) (Cox Analytical Systems, Mölndal, Sweden), provide high-resolution geochemical data within several hours. However, the semi-quantitative nature of these analysers has hampered their use to study pollution. This study explores Itrax’s capabilities to detect trace metals, such as Hg and Cd, in the Ría de Pontevedra harbour (NW Spain). A set of Itrax detection levels were proposed for each metal after comparison with quantitative measurements obtained from Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and Vapour Atomic Absorption Spectrometry (CVAAS) analyses. These quantitative data obtained after a sequential extraction were used to evaluate pollutant bioavailability and to determine metal pollution levels exhibiting Hg pollution. The reliability of inc/coh and Br/Cl ratios to assess the total organic matter variability was also evaluated. The results indicated that the Itrax is an efficient and fast option to monitor contamination, thereby avoiding laborious discrete analyses and reducing analytical cost and time.
显示更多 [+] 显示较少 [-]A Monte Carlo simulation based two-stage adaptive resonance theory mapping approach for offshore oil spill vulnerability index classification 全文
2014
Li, Pu | Chen, Bing | Li, Zelin | Zheng, Xiao | Wu, Hongjing | Jing, Liang | Lee, Kenneth
In this paper, a Monte Carlo simulation based two-stage adaptive resonance theory mapping (MC-TSAM) model was developed to classify a given site into distinguished zones representing different levels of offshore Oil Spill Vulnerability Index (OSVI). It consisted of an adaptive resonance theory (ART) module, an ART Mapping module, and a centroid determination module. Monte Carlo simulation was integrated with the TSAM approach to address uncertainties that widely exist in site conditions. The applicability of the proposed model was validated by classifying a large coastal area, which was surrounded by potential oil spill sources, based on 12 features. Statistical analysis of the results indicated that the classification process was affected by multiple features instead of one single feature. The classification results also provided the least or desired number of zones which can sufficiently represent the levels of offshore OSVI in an area under uncertainty and complexity, saving time and budget in spill monitoring and response.
显示更多 [+] 显示较少 [-]Assessment of ecological quality of coastal lagoons with a combination of phytobenthic and water quality indices 全文
2014
Christia, Chrysoula | Giordani, Gianmarco | Papastergiadou, Eva
Coastal lagoons are ecotones between continents and the sea. Coastal lagoons of Western Greece, subjected to different human pressures, were classified into four different types based on their hydromorphological characteristics and monitored over a three year period for their biotic and abiotic features. Six ecological indices based on water quality parameters (TSI-Chl-a, TSI-TP, TRIX), benthic macrophytes (E-MaQI, EEI-c) and an integrated index TWQI, were applied to assess the ecological status of studied lagoons under real conditions. The trophic status ranged from oligotrophic to hypertrophic according to the index applied. The ecological quality of transitional water ecosystems can be better assessed by using indices based on benthic macrophytes as changes in abundance and diversity of sensitive and tolerant species are the first evidence of incoming eutrophication. The multi-parametric index TWQI can be considered appropriate for the ecological assessment of these ecosystems due to its robustness and the simple application procedure.
显示更多 [+] 显示较少 [-]Levels of Persistent Organic Pollutants (POPs) in sediments from Lenga estuary, central Chile 全文
2014
Pozo, Karla | Urrutia, Roberto | Mariottini, Michela | Rudolph, Anny | Banguera, Julieth | Pozo, Katerine | Parra, Oscar | Focardi, S. (Silvano)
Superficial sediments from Lenga estuary in the VIII region of central Chile were analysed for Polychlorinated Biphenyls (PCBs) and Hexachlorobenzene (HCB). Organic carbon (OC) analysis was also performed and the statistical correlations (Pearson correlations) between compounds were also tested. Results showed the total PCB concentrations (ngg−1d.w.) fluctuated from ∼20 to 10,000. These levels are higher than those reported in other coastal sediments of the world. The PCB profile was dominated by middle to highly chlorinated congeners (6-Cl=40% and 7-Cl=30%). HCB concentrations (ngg−1d.w.), were lower than the PCBs and, fluctuated between 1 (at L1) and 870 (at L4). OC values ranged from 1% (L1) to 7% (L4) showing a significant positive correlations between OC% and PCBs (r=0.86; p<0.05) and for HCB (r=0.71). These results are an important contribution to knowledge of levels of POPs levels in coastal Chilean environments.
显示更多 [+] 显示较少 [-]Influence of the pore structure and surface chemical properties of activated carbon on the adsorption of mercury from aqueous solutions 全文
2014
Lu, Xincheng | Jiang, Jianchun | Sun, Kang | Wang, Jinbiao | Zhang, Yanping
Reactivation and chemical modification were used to obtain modified activated carbons with different pore structure and surface chemical properties. The samples were characterized by nitrogen absorption–desorption, Fourier transform infrared spectroscopy and the Bothem method. Using mercury chloride as the target pollutant, the Hg2+ adsorption ability of samples was investigated. The results show that the Hg2+ adsorption capacity of samples increased significantly with increases in micropores and acidic functional groups and that the adsorption process was exothermic. Different models and thermodynamic parameters were evaluated to establish the mechanisms. It was concluded that the adsorption occurred through a monolayer mechanism by a two-speed process involving both rapid adsorption and slow adsorption. The adsorption rate was determined by chemical reaction.
显示更多 [+] 显示较少 [-]Phase and sedimentation behavior of oil (octane) dispersions in the presence of model mineral aggregates 全文
2014
Gupta, Anju | Sender, Maximilian | Fields, Sarah | Bothun, Geoffrey D.
Adsorption of suspended particles to the interface of surfactant-dispersed oil droplets can alter emulsion phase and sedimentation behavior. This work examines the effects of model mineral aggregates (silica nanoparticle aggregates or SNAs) on the behavior of oil (octane)–water emulsions prepared using sodium bis(2-ethylhexyl) sulfosuccinate (DOSS). Experiments were conducted at different SNA hydrophobicities in deionized and synthetic seawater (SSW), and at 0.5mM and 2.5mM DOSS. SNAs were characterized by thermogravimetric analysis (TGA) and dynamic light scattering (DLS), and the emulsions were examined by optical and cryogenic scanning electron microscopy. In deionized water, oil-in-water emulsions were formed with DOSS and the SNAs did not adhere to the droplets or alter emulsion behavior. In SSW, water-in-oil emulsions were formed with DOSS and SNA–DOSS binding through cation bridging led to phase inversion to oil-in-water emulsions. Droplet oil-mineral aggregates (OMAs) were observed for hydrophilic SNAs, while hydrophobic SNAs yielded quickly sedimenting agglomerated OMAs.
显示更多 [+] 显示较少 [-]Australia’s pesticide environmental risk assessment failure: The case of diuron and sugarcane 全文
2014
Holmes, Glen
In November 2012, the Australian Pesticide and Veterinary Medicines Authority (APVMA) concluded a 12year review of the PSII herbicide diuron. One of the primary concerns raised during the review was the potential impact on aquatic ecosystems, particularly in the catchments draining to the Great Barrier Reef. The environmental risk assessment process used by the APVMA utilised a runoff risk model developed and validated under European farming conditions. However, the farming conditions in the sugarcane regions of the Great Barrier Reef catchments have environmental parameters beyond the currently validated bounds of the model. The use of the model to assess environmental risk in these regions is therefore highly inappropriate, demonstrating the pitfalls of a one size fits all approach.
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