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Investigation of the kinetics of oil–suspended particulate matter aggregation 全文
2013
Sun, Juan | Zhao, Dongfeng | Zhao, Chaocheng | Liu, Fang | Zheng, Xilai
The process of oil–suspended particulate matter aggregation (OSA) has been recognized by the oil spill remediation community to enhance the natural cleansing of oiled shorelines. A laboratory study was conducted to investigate the kinetics of OSA formation under various mixing intensities using the standard reference material 1941b and Arabian heavy crude oil. The results showed that formation of OSAs increased exponentially with mixing time and reached a maximum within 5h. The maximum oil trapping efficiency increased from 24% to 47%, and the required shaking time decreased from 4.5 to 1.2h as the sediment concentration and mixing energy increased. The maximum oil-to-sediment ratio reached 0.24–0.68g oil/g sediment within 5h. Most of the formed OSAs were solid OSAs and single droplet OSAs with low mixing energies, and multi-droplet OSAs with high mixing energies. The sizes of the dispersed oil droplets and OSAs were also investigated.
显示更多 [+] 显示较少 [-]The use of the brown macroalgae, Sargassum flavicans, as a potential bioindicator of industrial nutrient enrichment 全文
2013
Alquezar, Ralph | Glendenning, Lionel | Costanzo, Simon
Nutrient bioindicators are increasingly being recognised as a diagnostic tool for nutrient enrichment of estuarine and marine ecosystems. Few studies, however, have focused on field translocation of bioindicator organisms to detect nutrient discharge from industrial waste. The brown macroalgae, Sargassum flavicans, was investigated as a potential bioindicator of nutrient-enriched industrial effluent originating from a nickel refinery in tropical north-eastern Australia. S. flavicans was translocated to a number of nutrient enriched creek and oceanic sites over two seasons and assessed for changes in stable isotope ratios of 15N and 13C within the plant tissue in comparison to reference sites. Nutrient uptake in macroalgae, translocated to the nutrient enriched sites adjacent to the refinery, increased 3–4-fold in δ15N, compared to reference sites. Using δ15N of translocated S. flavicans proved to be a successful method for monitoring time-integrated uptake of nitrogen, given the current lack of passive sampler technology for nutrient monitoring.
显示更多 [+] 显示较少 [-]Personal exposure of commuters in public transport to PM2.5 and fine particle counts 全文
2013
Onat, Burcu | Stakeeva, Baktygul
To investigate fine particulate air pollution generated by public transport and its microenvironment, PM2.5 measurements and particle number counts for six particle size ranges (0.3–0.5 µm, >0.5–1.0 µm, >1.0–3.0 µm, >3.0– 5.0 µm, >5.0–10 µm and >10 µm) were obtained for four public transport modes: bus, metro–bus, car and walking. The measurements were repeated for each transport mode twice a day for 7–10 measurement days. The highest average PM2.5 concentration was measured inside a bus (106 µg/m3) during rush hours. The highest single peak measurement was a concentration of 316 µg/m3 for walking during non–rush hours. The PM2.5 level in a car with the air conditioning fan off was approximately 2.5 times lower than the level with the air conditioning fan on. Moderate correlations were found between PM2.5 concentrations and wind speed. Weak correlations were found between PM2.5 concentrations, relative humidity and temperature. The results showed that the diameters of most of the particles were smaller than 0.5 µm, regardless of the transport mode. The average fine particle number (size range 0.3–0.5) for all transport modes ranged from 54 647 to 209 746 particles/103 cm3 during rush hours and from 49 423 to 184 866 particles/103 cm3 during non–rush hours.
显示更多 [+] 显示较少 [-]Seasonal variation of metal contamination in the barnacles Pollicipes pollicipes in northwest coast of Portugal show clear correlation with levels in the surrounding water 全文
2013
Reis, Pedro A. | Salgado, María Antonia | Vasconcelos, Vitor
The concentrations of metals were determined in northwest (NW) coast of Portugal seawaters and soft tissues of goose barnacles Pollicipes pollicipes. P. pollicipes can be used for monitoring metal contamination in these coastal seawaters, because there were significant correlations (p<0.05) for all metals between soft tissues and seawaters during the four seasons. Metal concentrations in seawaters and P. pollicipes had significant (p<0.05) spatial and seasonal variations and mean log BAFs for Fe and Cd were higher than for Cr, Cu, Mn and Zn. Regarding the metal concentrations obtained in the coastal seawaters, all NW coast of Portugal should be classified as “Class IV – Bad”, except two locations (location 7 at Summer and location 10 at Winter), which should be classified as “Class III – Moderate”. However, considering the metal concentrations bioaccumulated in P. pollicipes, all locations should be classified as “Class III – Remarkably Polluted” during all seasons of 2011.
显示更多 [+] 显示较少 [-]Effectiveness of emetics to study plastic ingestion by Leach’s Storm-petrels (Oceanodroma leucorhoa) 全文
2013
Bond, Alexander L. | Lavers, Jennifer L.
Most plastic ingestion studies rely on dissection of dead birds, which are found opportunistically, and may be biased. We used Leach’s Storm-petrels (Oceanodroma leucorhoa) in Newfoundland to study the effect of dose volume, and the efficacy of emesis using syrup of ipecac as an emetic. Ipecac is a safe method of non-lethally sampling stomach contents, and recovered all ingested plastic. Almost half the storm-petrels sampled had ingested plastic, ranging from 0 to 17 pieces, and weighing 0.2–16.9mg. Using the Ecological Quality Objective for Northern Fulmars, adjusted for storm-petrels smaller size, 43% exceeded the threshold of 0.0077g of plastic. Many adult seabirds offload plastic to their offspring, so storm-petrel chicks likely experience a higher plastic burden than their parents. The ability to study plastic ingestion non-lethally allows researchers to move from opportunistic and haphazard sampling to hypothesis-driven studies on a wider range of taxa and age classes.
显示更多 [+] 显示较少 [-]Influence of size and density on filtration rate modeling and nutrient uptake by green mussel (Perna viridis) 全文
2013
Tantanasarit, Chayarat | Babel, Sandhya | Englande, A. J. | Shettapong Meksumpun,
This study investigates green mussel filtration rates based on variation of the mussel size and density, and attempts to correlate these with the amount of Chaetoceros calcitrans consumed by kinetic modeling. The filtration rates were found to be more effective in small mussels and with greater volumes of seawater/mussel which represent low mussel densities in the mussel farms. Under field condition, the first order kinetic model is useful for evaluation of mussel filtration rate. However, the composite exponential kinetic model was determined to better describe filtration rates in a close system. Higher ratios of seawater volume L/g DW mussel tissue, resulted in an increasing filtration rate until a maximum plateau was reached at 10.37L/h/g DW tissue as determined by first order kinetics. Based on the filtration rate, carbon, nitrogen, and phosphorus uptake by green mussels were found to be 2128.72, 265.41, and 66.67mg/year/indv, respectively.
显示更多 [+] 显示较少 [-]Assessment of cruise–ship activity influences on emissions, air quality, and visibility in Glacier Bay National Park 全文
2013
Mölders, Nicole | Gende, Scott | Pirhalla, Michael
An activity–based emission model was developed to determine cruise–ship emissions. Calculated emissions depend on cruise–voyage data (position, cruise speed, operation mode) and the ships’ characteristics (engine power, size, fuel– type, maximum cruise–speed). Cruise–ship emissions of particulate matter (PM) and its precursors were determined for the 2008 cruise season and for two proposed management actions: a prescribed speed in Glacier Bay, and implementation of an Emission Control Area (ECA) in Alaska at–large. The Weather Research and Forecasting model inline coupled with chemistry served to assess the impact of these management actions on air quality and visibility. On season–average, ships emitted ~2.5 µg/m2/s PM in Glacier Bay. Cruising at constant 6.69m/s anywhere in Glacier Bay decreased PM–emissions by 32% and marginally increased mean visibility. Altered cruise speeds strongly changed the spatial emission and concentration distributions of all species in and up to 30 km downwind of Glacier Bay. Changes differed among species. An ECA reduced PM–emissions from cruise ships by 74% and their impacts on visibility by 0.1, 0.2 and 0.1 deciview for the 10%, 50% and 90%–percentiles of best–visibility–days in Glacier Bay.
显示更多 [+] 显示较少 [-]Initial impacts of the Hebei Spirit oil spill on the sandy beach macrobenthic community west coast of Korea 全文
2013
Yu, Ok Hwan | Lee, Hyung-Gon | Shim, Won Joon | Kim, Moonkoo | Park, Heung-Sik
Petroleum hydrocarbon contamination and macrobenthos in the sandy tidal flats of Taean were monitored for 1year to assess the impacts of Hebei Spirit oil on the macrobenthic community. A total of 207 macrobenthic fauna was collected, and the mean density and biomass of macrobenthic fauna continued to decrease until 12months after the oil spill, but macrobenthic density at the most heavily affected sites increased by about twofold. In January 2008, the dominant species occurred at very low densities in strongly affected sites. The macrobenthic communities differed between oil-affected and unaffected sites. In particular, differences in community structure at Mallipo beach were larger than those at Shinduri. We suggest that long-term monitoring is needed to assess the specific effects of oil pollution on the sandy intertidal macrobenthic community.
显示更多 [+] 显示较少 [-]Activity levels of 210Po and 210Pb in some fish species of the Izmir Bay (Aegean Sea) 全文
2013
Aközcan, S. | Uğur, A.
Concentrations of 210Po and 210Pb were determined in the edible muscle tissue of twelve species of marine fish collected from Izmir Bay in the Aegean Sea Region of Turkey during the 2006–2007. 210Po activity concentrations in fish samples were found to vary from ND to 400±9Bqkg−1 dry weight and 210Pb activity concentrations were found to vary from ND to 15±3Bqkg−1 dry weight. The highest dose contribution due to 210Po to humans was found to be 8.908μSvy−1.
显示更多 [+] 显示较少 [-]Source characterization and spatio–temporal evolution of the metal pollution in the sediments of the Basque estuaries (Bay of Biscay) 全文
2013
Legorburu, Irati | Rodríguez, José Germán | Borja, Angel | Menchaca, Iratxe | Solaun, Oihana | Valencia Rincón, Victoriano | Galparsoro, Ibon | Larreta, Joana
According to Water Framework Directive requirements, Member States must identify and analyze effects derived from human pressures in aquatic systems. As different kind of pressures can impact water bodies at different scales, analyses of spatio-temporal evolution of water bodies becomes essential in order to understand ecosystem responses. In this investigation, an analysis of spatio-temporal evolution of sedimentary metal pollution (Cd, Cr, Cu, Hg, Ni, Pb, Zn) in 12 Basque estuaries (Bay of Biscay) is presented. Data collected in extensive sampling surveys is the basis for the GIS-based statistical approach used. The implementation of pollution abatement measures is reflected in a long-term decontamination process, mostly evident in estuaries with highest historical sediment pollution levels. Spatial evolution is determined by either naturally occurring or human driven processes. Such spatial processes are more obviously being reflected in estuaries with lower historical sediment pollution levels.
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