Refinar búsqueda
Resultados 741-750 de 2,529
Uncharted sources of particle bound polycyclic aromatic hydrocarbons from South Asia: Religious/ritual burning practices Texto completo
2014
Dewangan, Shippi | Pervez, Shamsh | Chakrabarty, Rajan | Zielinska, Barbara
This paper deals with the real–world emissions of particle bound polycyclic aromatic hydrocarbons (PAHs) emitted from different religious and ritual burning practices in India. The emission factors (EFs) of various PAHs were characterized over integrated stages of burning practices including pyrolysis, flaming and smoldering. Sampling was carried out in selected five different types of religious and ritual places: Hindu Temples (HT), Muslim Holy shrines (MG), Buddhist Temples (BT), Hindu Marriage Places (MP) and Cremation Centers (Hindu Funeral Pyre) (CC); where burning practices mostly include natural and synthetic biomaterials in different proportions. Seventy PAHs were analyzed and grouped in light PAHs (LPAHs=25) and heavy PAHs (HPAHs=45) according to number of benzene rings present and respective molecular weights. The average EF of total PAHs (TPAHs) from MP, MG, BT, HT and CC is estimated as 77.04±5.39, 99.09±6.02, 90.35±6.76, 22.78±1.57, and 77.15±6.16mg kg−1, respectively. Country level emission budget of particulate bound TPAHs from religious and ritual burning practices has also been evaluated to 0.47Gg yr−1; contributed ~23% of the 2.07Gg yr−1 – Indian emission budget of PAHs from unknown sources reported earlier.
Mostrar más [+] Menos [-]Monthly variation of trace metals in North Sea sediments. From experimental data to modeling calculations Texto completo
2014
Lourino-Cabana, B. | Billon, G. | Lesven, L. | Sabbe, K. | Gillan, D.-C. | Gao, Y. | Leermakers, M. | Baeyens, W.
Seasonal variation in trace metal contamination in surface sediments was studied through high resolution profiles assessed monthly by DGT probes in muddy sediments of the North Sea. General parameters such as pH, temperature, dissolved oxygen and sulfides were also recorded to estimate their role in the speciation of trace metals. Experimental data were included in a thermodynamic equilibrium model to calculate major (geo)chemical processes at the water–sediment interface and to predict the fate of the trace metals in case of (physico-)chemical changes. Results showed lowest Fe, Co, Ni and Cd concentrations in summer, which are most probably due to the very high sulfide concentrations according to our theoretical calculations. Cu and Pb behavior were found to be less influenced by sulfides, since they are also strongly associated to organic matter. The whole set of results clearly indicated that metal speciation in these sediments is controlled by sulfides and OM contents.
Mostrar más [+] Menos [-]Physiological disturbance of the Manila clam, Ruditapes philippinarum, by altered environmental conditions in a tidal flat on the west coast of Korea Texto completo
2014
Baek, Min Jeong | Lee, Young-Jae | Choi, Kwang-Sik | Lee, Won-Chan | Park, Hyun Je | Kwak, Jung Hyun | Kang, Chang-Keun
To examine the influence of habitat alteration by tideflat reclamation on the physiological ecology of Ruditapes philippinarum, seasonal variations in its condition, gross biochemical composition, and reproductive cycle were compared for a yearly cycle between a reclaimed flat (Gomsohang, GS) and a natural flat (Hajun, HJ) in Gomso Bay, Korea. Concentrations of chlorophyll a and seston (as well as its energy value as food available to the clam) were consistently higher at HJ than at GS. Condition, dry tissue weight, and energy reserves (proteins and carbohydrates) of the clams were much higher at HJ than at GS during spring–summer, when fast growth and gametogenic development occur. Furthermore, their spring gametogenic development and spawning were advanced at HJ compared with GS. Our results suggest that the Manila clam encounters nutritionally stressful environmental conditions in altered habitats after tideflat reclamation that lead to lowered nutrient accumulation and a changing reproductive cycle.
Mostrar más [+] Menos [-]Enzymatic methods for the determination of pollution in seawater using salt resistant alkaline phosphatase from eggs of the sea urchin Strongylocentrotus intermedius Texto completo
2014
Menzorova, Natalie I. | Seitkalieva, Alexandra V. | Rasskazov, Valerу A.
A new salt resistant alkaline phosphatase from eggs of the sea urchin Strongylocentrotus intermedius (StAP) has been shown to have a unique property to hydrolyze substrate in seawater without loss of enzymatic activity. The enzyme has pH optimum at 8.0–8.5. Model experiments showed various concentrations of copper, zinc, cadmium and lead added to seawater or a standard buffer mixture to inhibit completely the enzyme activity at the concentrations of 15–150μg/l. StAP sensitivity to the presence in seawater of metals, pesticides, detergents and oil products appears to be considerably less. Samples of seawater taken from aquatic areas of the Troitsy Bay of the Peter the Great Bay, Japan Sea have been shown to inhibit the enzyme activity; the same was shown for the samples of fresh waters. The phosphatase inhibition assay developed proved to be highly sensitive, technically easy-to use allowing to test a great number of samples.
Mostrar más [+] Menos [-]Contingency plan improvement for managing oil spills in the coastal waters of Thailand Texto completo
2014
Singkran, Nuanchan
The estimated risks of being impacted by oil spills in the coastal waters were used to improve the oil spill contingency plan of Thailand. Functional roles of local agencies are integrated into the plan. Intensive measures are suggested for the coastal provinces located in high-very high risk zones, whereas light and moderate measures are suggested for the coastal provinces located in low and moderate risk zones, respectively. The estimated percentage risks due to simulated oil slicks hitting the coast and/or important resources (PRoilspill) were used to guide the year-round water activities that should be carefully handled at a certain radius with a low-moderate PRoilspill, whereas they should be avoided at a certain radius with a high-very high PRoilspill. Important measures before, during, and post periods of an oil spill incident are suggested to prevent and monitor oil spill incidents and mitigate their impacts on the environment.
Mostrar más [+] Menos [-]All aboard! A biological survey of ballast water onboard vessels spanning the North Atlantic Ocean Texto completo
2014
Steichen, Jamie L. | Schulze, Anja | Brinkmeyer, Robin | Quigg, Antonietta
Global movement of nonindigenous species, within ballast water tanks across natural barriers, threatens coastal and estuarine ecosystem biodiversity. In 2012, the Port of Houston ranked 10th largest in the world and 2nd in the US (waterborne tonnage). Ballast water was collected from 13 vessels to genetically examine the eukaryotic microorganism diversity being discharged into the Port of Houston, Texas (USA). Vessels took ballast water onboard in North Atlantic Ocean between the Port of Malabo, Africa and Port of New Orleans, Louisiana, (USA). Twenty genera of Protists, Fungi and Animalia were identified from at least 10 phyla. Dinoflagellates were the most diverse and dominant identified (Alexandrium, Exuviaella, Gyrodinium, Heterocapsa, Karlodinium, Pfiesteria and Scrippsiella). We are reporting the first detection of Picobiliphytes, Apusozoa (Amastigomonas) and Sarcinomyces within ballast water. This study supports that global commerce by shipping contributes to long-distance transportation of eukaryotic microorganisms, increasing propagule pressure and invasion supply on ecosystems.
Mostrar más [+] Menos [-]Marine debris in bottom trawl catches and their effects on the selectivity grids in the north eastern Mediterranean Texto completo
2014
Eryaşar, Ahmet Raif | Özbilgin, Hüseyin | Gücü, Ali Cemal | Sakınan, Serdar
In this study composition of marine debris and their blocking potential on the selectivity grid systems deployed on demersal trawls were investigated in the north eastern Mediterranean. For this, a total of 132hauls were examined in two fishing season between 20 September 2010 and 19 February 2012. Results showed that plastic items were the most abundant debris (73% in terms of weight) and they were followed by metals (10%). Because of plastics and packing debris, it is highly probable that grids may have been blocked in 85% of trawl hauls. The bathymetric and geographical variability in the quantity of debris were evaluated, and concluded that particularly in some areas where direction of currents and bottom topography favor deposition, such devices may easily be rendered ineffective by the plastics and packing debris in particular. To solve this problem, several solution proposals are submitted.
Mostrar más [+] Menos [-]Early contamination of European flounder (Platichthys flesus) by PCDD/Fs and dioxin-like PCBs in European waters Texto completo
2014
Nunes, Margarida | Martinho, Filipe | Vernisseau, Anaïs | Marchand, Philippe | Le Bizec, Bruno | van der Veer, Henk W. | Cabral, Henrique N. | Ramos, Fernando | Pardal, Miguel A.
Contamination levels and profiles of 7 polychlorinated-p-dioxins, 10 polychlorinated furans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) were investigated in juvenile European flounder (Platichthys flesus) captured in different nursery areas in the northeastern Atlantic coast across its geographical distribution range. The toxic equivalent concentrations (WHO-TEQfish) were also determined in order to evaluate which P. flesus population was more exposed to dioxin-like toxicity. Juveniles caught in the Sørfjord (Norway) showed the lowest WHO-TEQfish concentration (0.052pg WHO-TEQfishg−1wet weight) whereas the highest value was observed in fish from the Wadden Sea (The Netherlands; 0.291pg WHO-TEQfishg−1ww), mainly due to the greater contribution of 2,3,7,8-tetrachlorodibenzo-p-dioxin, the most toxic congener. Nonetheless, when comparing the results with existent tissue residue-based toxicity benchmarks, no adverse effects resulting from PCDD/Fs and dl-PCBs are expected to occur in flounder from the studied systems.
Mostrar más [+] Menos [-]Oil spill hazard assessment using a reverse trajectory method for the Egadi marine protected area (Central Mediterranean Sea) Texto completo
2014
Ciappa, Achille | Costabile, Salvatore
The Egadi Marine Protected Area (MPA) on the western side of the Sicily Channel (Central Mediterranean) is exposed to a high risk of oil pollution from the tanker routes connecting the eastern and western basins of the Mediterranean Sea. Areas where an oil spill would do most damage, and thus where surveillance should be concentrated, are identified in this study by Lagrangian tracers tracked backwards in time from points along the MPA perimeter using data spanning six years from 2006 to 2011. Results indicate that the areas where oil surveillance would be most beneficial are segments of the tanker routes south of Sicily (highly frequented) and north of Sicily (scarcely frequented), both extending about 150 miles from November to March and 100 miles in the other months. The third route, close to the Tunisian shore, is the most frequented by oil tankers but the threat period is limited to November and December.
Mostrar más [+] Menos [-]Depletion and biodegradation of hydrocarbons in dispersions and emulsions of the Macondo 252 oil generated in an oil-on-seawater mesocosm flume basin Texto completo
2014
Brakstad, Odd G. | Daling, Per S. | Faksness, Liv-G. | Almås, Inger K. | Vang, Siv-H. | Syslak, Line | Leirvik, Frode
Physically and chemically (Corexit 9500) generated Macondo 252 oil dispersions, or emulsions (no Corexit), were prepared in an oil-on-seawater mesocosm flume basin at 30–32°C, and studies of oil compound depletion performed for up to 15days. The use of Corexit 9500 resulted in smaller median droplet size than in a physically generated dispersion. Rapid evaporation of low boiling point oil compounds (C⩽15) appeared in all the experiments. Biodegradation appeared to be an important depletion process for compounds with higher boiling points in the dispersions, but was negligible in the surface emulsions. While n-alkane biodegradation was faster in chemically than in physically dispersed oil no such differences were determined for 3- and 4-ring PAH compounds. In the oil dispersions prepared by Corexit 9500, increased cell concentrations, reduction in bacterial diversity, and a temporary abundance of bacteria containing an alkB gene were associated with oil biodegradation.
Mostrar más [+] Menos [-]