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Surface oil footprint and trajectory of the Ixtoc-I oil spill determined from Landsat/MSS and CZCS observations Texte intégral
2015
Sun, Shaojie | Hu, Chuanmin | Tunnell, John W.
The Ixtoc-I oil spill occurred in 1979 in shallow waters (50m) of the Bay of Campeche, Mexico. Although it is known that a large portion of the released oil from this second largest accidental marine oil spill in history reached the surface, to date there has been no attempt to document the surface footprint and trajectory of the released oil. Our study attempts to fill this knowledge gap using remote sensing data collected by Landsat/MSS and CZCS. Both showed the same general patterns of oil trajectory to the northwest and north, nearly parallel to the coastline of the western Gulf of Mexico (GoM) with possible oil landing on Mexican and Texas beaches. Field observations at selected beaches and islands along the coast of the western and southern GoM during and after the spill confirmed these satellite-based findings, which were also used to help in planning a recent field campaign to collect sediment samples in the southern GoM.
Afficher plus [+] Moins [-]A new approach to the prediction of PM10 concentrations in Central Anatolia Region, Turkey Texte intégral
2015
Ozel, Gamze | Cakmakyapan, Selen
Environmental pollution control is one of the most important goals in pollution risk assessment. In this sense, modern and precise tools that allow scientists to quantify and predict air pollution are of particular interest. In this study, we describe an air quality evaluation in terms of particulate matter having a diameter < 10μm (PM10), using a gamma–Poisson process. PM10 measurements from 2007 to 2013 at 24 air quality monitoring stations of Ministry of Environment and Urbanization (Turkey), was used to predict air pollution levels in Central Anatolia Region of Turkey. We assume that the number of PM10 peaks follows a Poisson process and PM10 amount of each peak fits a gamma distribution. The findings indicate that daily average of number for the threshold exceedance of PM10 concentration is 1.3 for all monitoring stations. The probability of exceedance the PM10 concentration threshold once a day is 0.35 for all monitoring stations. The results also show that the probabilities of total PM10 concentrations exceeding threshold are rapidly decreasing after 158μg/m3 which will occur in one day. The average of daily total PM10 concentration is 148μg/m3, the average of monthly total PM10 concentration is 4 437μg/m3, and the average of yearly total PM10 concentrations is 53 984μg/m3. It is found that there is a moderate correlation between the number of threshold exceedances and the total PM10 concentrations in Central Anatolia Region. Thus, it was concluded that gamma–Poisson process could be promising for air pollutant prediction for a given period of time.
Afficher plus [+] Moins [-]Chemical comparison and acute toxicity of water accommodated fraction (WAF) of source and field collected Macondo oils from the Deepwater Horizon spill Texte intégral
2015
Faksness, Liv-Guri | Altin, Dag | Nordtug, Trond | Daling, Per S. | Hansen, Bjørn Henrik
Two Source oils and five field collected oil residues from the Deepwater Horizon incident were chemically characterized. Water accommodated fractions (WAFs) of the Source oils and two of the field-weathered oils were prepared to evaluate the impact of natural weathering on the chemical composition and the acute toxicity of the WAFs. Toxicity test species representing different tropic levels were used (the primary producer Skeletonema costatum (algae) and the herbivorous copepod Acartia tonsa). The results suggest that the potential for acute toxicity is higher in WAFs from non-weathered oils than WAFs from the field weathered oils. The Source oils contained a large fraction of soluble and bioavailable components (such as BTEX (benzene, toluene, ethyl benzene, xylenes) and naphthalene), whereas in the surface collected oils these components were depleted by dissolution into the water column as the oil rose to the surface and by evaporative loss after reaching the sea surface.
Afficher plus [+] Moins [-]Macrofaunal recolonization of copper-contaminated sediments in San Diego Bay Texte intégral
2015
Neira, Carlos | Mendoza, Guillermo | Porrachia, Magali | Stransky, Chris | Levin, Lisa A.
Effects of Cu-loading on macrofaunal recolonization were examined in Shelter Island Yacht Basin (San Diego Bay, California). Sediments with high and low Cu levels were defaunated and Cu-spiked, translocated, and then placed back into the environment. These demonstrated that the alteration observed in benthic communities associated with Cu contamination occurs during initial recolonization. After a 3-month exposure to sediments with varying Cu levels, two primary colonizing communities were identified: (1) a “mouth assemblage” resembling adjacent background fauna associated with low-Cu levels that was more diverse and predominantly dominated by surface- and subsurface-deposit feeders, burrowers, and tube builders, and (2) a “head assemblage” resembling adjacent background fauna associated with high-Cu concentrations, with few dominant species and an increasing importance of carnivores and mobile epifauna. Cu loading can cause reduced biodiversity and lower structural complexity that may last several months if high concentrations persist, with a direct effect on community functioning.
Afficher plus [+] Moins [-]Environmental triggers for primary outbreaks of crown-of-thorns starfish on the Great Barrier Reef, Australia Texte intégral
2015
Wooldridge, Scott A. | Brodie, J. E. (Jon E.)
In this paper, we postulate a unique environmental triggering sequence for primary outbreaks of crown-of-thorns starfish (COTS, Acanthaster planci) on the central Great Barrier Reef (GBR, Australia). Notably, we extend the previous terrestrial runoff hypothesis, viz. nutrient-enriched terrestrial runoff→elevated phytoplankton ‘bloom’ concentrations→enhanced COTS larval survival, to include the additional importance of strong larvae retention around reefs or within reef groups (clusters) that share enhanced phytoplankton concentrations. For the central GBR, this scenario is shown to occur when El Niño-Southern Oscillation (ENSO) linked hydrodynamic conditions cause the ‘regional’ larval connectivity network to fragment into smaller ‘local’ reef clusters due to low ocean current velocities. As inter-annual variations in hydrodynamic circulation patterns are not amenable to direct management intervention, the ability to reduce the future frequency of COTS outbreaks on the central GBR is shown to be contingent on reducing terrestrial bioavailable nutrient loads ~20–40%.
Afficher plus [+] Moins [-]Evaluation for coastal reclamation feasibility using a comprehensive hydrodynamic framework: A case study in Haizhou Bay Texte intégral
2015
Feng, Lan | He, Jia | Ai, Junyong | Sun, Xiang | Bian, Fangyuan | Zhu, Xiaodong
Coastal reclamation (CR) is a prevailing approach to solve the contradiction between the land shortage and the growing demand of living space for human beings. In general, environmental impact assessment (EIA) focuses on evaluating the feasibility of individual coastal reclamation project (CRP). However, few studies have investigated the cumulative effect of multiple CRPs on surrounding environment. In this study, an integrated framework based on coastal hydrodynamics was established, and then applied to the feasibility evaluation of multiple CRPs for future coastal management in Haizhou Bay, China. The results indicated that three out of five reclamation projects were feasible and the remaining two were forbidden in the study area, whereas EIA approves of all the CRPs. It provides a scientific reference for effective management of coastal reclamation and future environmental impact researches when new CRPs are proposed.
Afficher plus [+] Moins [-]Assessment of the European flounder responses to chemical stress in the English Channel, considering biomarkers and life history traits Texte intégral
2015
Dupuy, Célie | Galland, Claire | Pichereau, Vianney | Sanchez, Wilfried | Riso, Ricardo | Labonne, Maylis | Amara, Rachid | Charrier, Grégory | Fournier, Michel | Laroche, Jean
A multi-biomarker approach was developed to evaluate responses of European flounder (Platichthys flesus) in three contrasted estuaries over the English Channel: the Canche (pristine site), Tamar (heavy metals and PAHs contamination) and Seine (heavily pollution with a complex cocktail of contaminants). The condition factor and several biomarkers of the immune system, antioxidant enzymes, energetic metabolism and detoxification processes were investigated in young-of-the-year (0+) and one-year-old (1+) flounder. Results underlined the difference between the pristine site and the Seine estuary which showed a lower condition factor, a modulation of the immune system, a higher Cytochrome C oxidase activity, and an up-regulation of BHMT expression. The moderate biomarker responses in the Tamar fish could be linked to the specific contamination context of this estuary. Flounder life history traits were analyzed by otolith microchemistry, in order to depict how the fish use their habitat and thus respond to chemical stress in estuaries.
Afficher plus [+] Moins [-]Repeated rapid assessment surveys reveal contrasting trends in occupancy of marinas by non-indigenous species on opposite sides of the western English Channel Texte intégral
2015
Bishop, John D.D. | Wood, Christine A. | Lévêque, Laurent | Yunnie, Anna L.E. | Viard, Frédérique
Rapid assessment surveys of non-indigenous species (NIS) of sessile invertebrates were made at seven marinas in NW France and 10 marinas in SW England in 2010, and repeated in 2013. Fourteen NIS were recorded, 12 of which were seen on both coasts. Site occupancy differed between the opposite sides of the western English Channel. In Brittany, most species occurred at most sites in both 2010 and 2013. In 2010, site occupancy in Devon & Cornwall was distinctly lower; by 2013, the difference compared to Brittany had narrowed considerably, largely because of rapid colonisation of additional sites by species that were infrequent in 2010. Three more of the recent NIS are present in Devon & Cornwall but have still not become widespread. It is concluded that the recently introduced fouling animals studied here are longer established in NW France than in SW England, and have probably spread northwards across the Channel.
Afficher plus [+] Moins [-]Environmental fate and ecological risks of nonylphenols and bisphenol A in the Cape D’Aguilar Marine Reserve, Hong Kong Texte intégral
2015
Xu, Elvis G.B. | Morton, Brian | Lee, Joseph H.W. | Leung, Kenneth M.Y.
Nonylphenols (NPs) and bisphenol A (BPA) are the most common endocrine disruptors detected in the coastal waters of Hong Kong. The Cape D’Aguilar Marine Reserve (CAMR), the only marine reserve in Hong Kong is close to urbanized areas, thus the resident marine organisms are inevitably influenced by partially treated wastewater from adjacent sewage treatment plants (STPs). Elevated levels of NPs and BPA were detected in all seawater, sediment and biota samples collected from the CAMR. Estrogenic activities of seawater from the CAMR, and sludge and sewage from a nearby STP were assessed using yeast estrogen screen assay. We found aromatase, estrogen receptor and vitellogenin genes in the marine medaka fish Oryzias melastigma were significantly up-regulated after exposure to the reserve’s seawater. According to a tissue-residue-based probabilistic risk assessment, the marine species living in the CAMR are having 35% and 21% of chance to be at risk due to exposure to NPs and BPA, respectively.
Afficher plus [+] Moins [-]Assessment of swimming associated health effects in marine bathing beach: An example from Morib beach (Malaysia) Texte intégral
2015
Praveena, Sarva Mangala | Pauzi, Norfasmawati Mohd | Hamdan, Munashamimi | Sham, Shaharuddin Mohd
A survey among beachgoers was conducted to determine the swimming associated health effects experienced and its relationship with beach water exposure behaviour in Morib beach. For beach water exposure behaviour, the highest frequency of visit among the respondents was once a year (41.9%). For ways of water exposure, whole body exposure including head was the highest (38.5%). For duration of water exposure, 30.8% respondents prefer to be in water for about 30min with low possibilities of accidental ingestion of beach water. A total of 30.8% of beachgoers in Morib beach were reported of having dermal symptoms. Bivariate analysis showed only water activity, water contact and accidental ingestion of beach water showed significant association with swimming associated health effects experienced by swimmers. This study output showed that epidemiological study can be used to identify swimming associated health effects in beach water exposed to faecal contamination.
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