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Resultados 1151-1160 de 3,207
Levels and spatial distribution of perfluoroalkyl substances in China Liaodong Bay basin with concentrated fluorine industry parks Texto completo
2015
Chen, Hong | Zhang, Can | Han, Jianbo | Sun, Ruijun | Kong, Xiangyun | Wang, Xiaomeng | He, Xin
Eighteen different perfluoroalkyl substances (PFASs) were investigated in 35 river water samples and 34 sediment samples collected from rivers in the Liaodong Bay basin containing two fluorine industry parks. Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) were the predominant PFASs in freshwater, with median concentrations of 26.5ng/L and 1.87ng/L, respectively. However, perfluorobutane sulfonate (PFBS) had the highest maximum concentration (up to 124.1ng/L, approximately two orders of magnitude higher) in water at a site which is the nearest to the industrial source of PFASs. Total PFASs in water at this site were also the highest. In contrast, PFOA and perfluorooctadecanoate (PFOcDA) were the most abundant PFASs in sediment, with median concentrations of 1.19ng/g and 0.35ng/g, respectively. Total PFAS concentrations in sediment from the site near to the industrial park were significantly higher than the other rivers. Mass loading of total PFASs from the rivers flowing into Liaodong Bay was estimated to be 506kg/year.
Mostrar más [+] Menos [-]Organochlorine contaminants and maternal offloading in the lecithotrophic Pacific angel shark (Squatina californica) collected from southern California Texto completo
2015
Lyons, Kady | Lowe, Christopher G.
Pacific angel sharks (Squatina californica) are a benthic elasmobranch that occupy intermediate trophic level positions in coastal food webs. Angel sharks’ life history characteristics make them susceptible to accumulating high amounts of contaminants. Four angel sharks were opportunistically captured in southern California and their liver and uterine contents were analyzed for PCBs, DDTs and other pesticides. High DDT:PCB ratios were found in the sharks indicating direct or indirect foraging near a local EPA Superfund Site. Organic contaminants were measured in ovulated eggs, indicating that females are able to maternally offload contaminants. Despite the potential mismatch between ovarian and uterine fecundity, we estimated females to offload approximately 13±5% of their total body load, which represents the upper limit of this capability. Although low in sample size, the initial findings from this study suggest that habitat use might play an important role in contaminant accumulation in this species.
Mostrar más [+] Menos [-]Spatial–temporal variations and diversity of the bacterioplankton communities in the coastal waters of Kuwait Texto completo
2015
Almutairi, Awatef
The dynamics and composition of the bacterial community in the coastal waters of Kuwait are poorly understood. In this study, the spatial–temporal variations in the bacterial composition in the surface water along the Kuwaiti coast was examined by 16S rRNA denaturing gradient gel electrophoresis (DGGE) fingerprinting and phylogeny analyses. The sampling sites were Kuwait Bay, Al-Sabbiya (north of the bay) and Al-Khairan (to the south). The bacterial composition was more variable in the summer for all sites. A cluster analysis of the DGGE fingerprint revealed two main clusters, indicating a temporal similarity between sites. Kuwait Bay and Al-Khairan were more similar to each other than to Al-Sabbiya. The bacterial community composition exhibited distinctive spatial variations, with more diversity at Al-Khairan and less diversity at Al-Sabbiya. At all sites, the dominant bacteria were Alphaproteobacteria, in particular Rhodobacteraceae, followed by Alteromonadaceae (Gammaproteobacteria) and Bacteroidetes.
Mostrar más [+] Menos [-]Evaluation for coastal reclamation feasibility using a comprehensive hydrodynamic framework: A case study in Haizhou Bay Texto completo
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.
Mostrar más [+] Menos [-]Renewables-to-reefs? – Decommissioning options for the offshore wind power industry Texto completo
2015
Smyth, K. (Katie) | Christie, Nikki | Burdon, Daryl | Atkins, Jonathan P. | Barnes, Richard | Elliott, Michael
The offshore wind power industry is relatively new but increasing globally, hence it is important that the whole life-cycle is managed. The construction–operation–decommissioning cycle is likely to take 20–30years and whilst decommissioning may not be undertaken for many years, its management needs to be addressed in both current and future marine management regimes. This can be defined within a Drivers–Activities–Pressures–State Changes–Impacts (on human Welfare)–Responses framework. This paper considers the main decommissioning options – partial or complete removal of all components. A SWOT analysis shows environmental and economic benefits in partial as opposed to complete removal, especially if habitat created on the structures has conservation or commercial value. Benefits (and repercussions) are defined in terms of losses and gains of ecosystem services and societal benefits. The legal precedents and repercussions of both options are considered in terms of the 10-tenets of sustainable marine management. Finally a ‘renewables-to-reefs’ programme is proposed.
Mostrar más [+] Menos [-]Metal elements in the bottom sediments of the Changjiang Estuary and its adjacent continental shelf of the East China Sea Texto completo
2015
Cao, Lu | Hong, Gi Hoon | Liu, Sumei
The metal elements (Al, Fe, Mn, Cr, Co, Ni, Cu, Zn, As, Pb and Ca) in the bottom sediment of the Changjiang Estuary and its adjacent continental shelf of the East China Sea were studied to map their spatial distribution and to assess their potential risk to the marine biota. These metal concentrations except Ca were generally higher in the inner shelf and northeastern part, and were found to decrease from the coast to the offshore of the Changjiang Estuary. Sedimentary Ca was most abundant in the outer shelf sediments and decreased in inner shelf. Arsenic (As) appeared to be contaminated due to economic development from 1980s in the inner shelf overall, but the potential ecological risk from the selected metals was low in the coastal sea off the Changjiang.
Mostrar más [+] Menos [-]A metabolomic investigation of the effects of metal pollution in oysters Crassostrea hongkongensis Texto completo
2015
Ji, Chenglong | Wang, Qing | Wu, Huifeng | Tan, Qiaoguo | Wang, Wen-Xiong
Metal pollution has been of great concern in the estuaries in Southern China. In this study, metabolic differences between oysters Crassostrea hongkongensis from clean and metal-polluted sites were characterized using NMR-based metabolomics. We collected oyster samples from one clean (Jiuzhen) and two metal polluted sites (Baijiao and Fugong). The metal concentrations in oyster gills indicated that both the Baijiao and Fugong sites were severely polluted by several metals, including Cr, Ni, Cu, Zn, Ag, Cd and Pb. In particular, Cu and Zn were the major contaminants from the Baijiao and Fugong sites. Compared with those oysters from the clean site (JZ), metal pollution in BJ and FG induced disturbances in osmotic regulation and energy metabolism via different metabolic pathways, as indicated by different metabolic biomarkers. This study demonstrates that NMR-based metabolomics is a useful tool for characterizing metabolic responses induced by metal pollution.
Mostrar más [+] Menos [-]Responses of estuarine nematodes to an increase in nutrient supply: An in situ continuous addition experiment Texto completo
2015
Ferreira, R.C. | Nascimento-Junior, A.B. | Santos, P.J.P. | Botter-Carvalho, M.L. | Pinto, T.K.
An experiment was carried out on an estuarine mudflat to assess impacts of inorganic nutrients used to fertilize sugar-cane fields on the surrounding aquatic ecosystem, through changes in the nematode community structure. During 118days, nine quadrats each 4m2 were sampled six times after the beginning of fertilizer addition. The fertilizer was introduced weekly in six areas, at two different concentrations (low and high doses), and three areas were used as control. The introduction of nutrients modified key nematode community descriptors. In general, the nematodes were negatively affected over the study period. However, Comesa, Metachromadora, Metalinhomoeus, Spirinia and Terschellingia were considered tolerant, and other genera showed different degrees of sensitivity. Nutrient input also affect the availability and quality of food, changing the nematode trophic structure. The use of inorganic fertilizer should be evaluated with care because of the potential for damage to biological communities of coastal aquatic systems.
Mostrar más [+] Menos [-]Environmental parameters influence on the dynamics of total and pathogenic Vibrio parahaemolyticus densities in Crassostrea virginica harvested from Mexico’s Gulf coast Texto completo
2015
López-Hernández, Karla M. | Pardío-Sedas, Violeta T. | Lizárraga-Partida, Leonardo | Williams, José de J. | Martínez-Herrera, David | Flores-Primo, Argel | Uscanga-Serrano, Roxana | Rendón-Castro, Karla
The influence of environmental parameters on the total and pathogenic Vibrio parahaemolyticus seasonal densities in American oysters (Crassostrea virginica) was evaluated for 1year. Harvesting site A yielded the highest mean densities of V. parahaemolyticus tlh+, tdh+/trh−, tdh−/trh+ and tdh+/trh+ during spring season at 2.57, 1.74, 0.36, and −0.40 log10MPN/g, respectively, and tdh+/orf8+ during winter season (0.90 log10MPN/g). V. parahaemolyticus tlh+ densities were associated to salinity (R2=0.372, P<0.022), tdh+/trh+ to turbidity (R2=0.597, P<0.035), and orf8+ to temperature, salinity, and pH (R2=0.964, P<0.001). The exposure to salinity and temperature conditions during winter and spring seasons regulated the dynamics of V. parahaemolyticus harboring potentially pathogenic genotypes within the oyster. The adaptive response of V. parahaemolyticus to seasonal environmental changes may lead to an increase in survival and virulence, threatening the seafood safety and increasing the risk of illness.
Mostrar más [+] Menos [-]A new approach to the prediction of PM10 concentrations in Central Anatolia Region, Turkey Texto completo
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.
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