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Distribution and concentrations of petroleum hydrocarbons associated with the BP/Deepwater Horizon Oil Spill, Gulf of Mexico Texto completo
2013
Sammarco, Paul W. | Kolian, Steve R. | Warby, Richard A.F. | Bouldin, Jennifer L. | Subra, Wilma A. | Porter, Scott A.
We examined the geographic extent of petroleum hydrocarbon contamination in sediment, seawater, biota, and seafood during/after the BP/Deepwater Horizon Oil Spill (April 20–July 15, 2010; 28.736667°N, −88.386944°W). TPH, PAHs, and 12 compound classes were examined, particularly C1-benzo(a)anthracenes/chrysenes, C-2-/C-4-phenanthrenes/anthracenes, and C3-naphthalenes. Sediment TPH, PAHs, and all classes peaked near Pensacola, Florida, and Galveston, Texas. Seawater TPH peaked off Pensacola; all of the above classes peaked off the Mississippi River, Louisiana and Galveston. Biota TPH and PAHs peaked near the Mississippi River; C-3 napthalenes peaked near the spill site. Seafood TPH peaked near the spill site, with PAHs and all classes peaking near Pensacola. We recommend that oil concentrations continued to be monitored in these media well after the spill has ceased to assist in defining re-opening dates for fisheries; closures should be maintained until hydrocarbon levels are deemed within appropriate limits.
Mostrar más [+] Menos [-]Impact of flood events on macrobenthic community structure on an intertidal flat developing in the Ohta River Estuary Texto completo
2013
Nishijima, Wataru | Nakano, Yoichi | Nakai, Satoshi | Okuda, Tetsuji | Imai, Tsuyoshi | Okada, Mitsumasa
We investigated the effects of river floods on the macrobenthic community of the intertidal flat in the Ohta River Estuary, Japan, from 2005 to 2010. Sediment erosion by flood events ranged from about 2–3cm to 12cm, and the salinity dropped to 0‰ even during low-intensity flood events. Cluster analysis of the macrobenthic population showed that the community structure was controlled by the physical disturbance, decreased salinity, or both. The opportunistic polychaete Capitella sp. was the most dominant species in all clusters, and populations of the long-lived polychaete Ceratonereis erythraeensis increased in years with stable flow and almost disappeared in years with intense flooding. The bivalve Musculista senhousia was also an important opportunistic species that formed mats in summer of the stable years and influenced the structure of the macrobenthic community. Our results demonstrate the substantial effects of flood events on the macrobenthic community structure.
Mostrar más [+] Menos [-]Thorium(IV) removal from aqueous medium by citric acid treated mangrove endophytic fungus Fusarium sp. #ZZF51 Texto completo
2013
Yang, S.K. | Tan, N. | Yan, X.M. | Chen, F. | Long, W. | Lin, Y.C.
Thorium(IV) biosorption is investigated by citric acid treated mangrove endophytic fungus Fussarium sp. #ZZF51 (CA-ZZF51) from South China Sea. The biosorption process was optimized at pH 4.5, equilibrium time 90min, initial thorium(IV) concentration 50mgL−1 and adsorbent dose 0.6gL−1 with 90.87% of removal efficiency and 75.47mgg−1 of adsorption capacity, which is obviously greater than that (11.35mgg−1) of the untreated fungus Fussarium sp. #ZZF51 for thorium(IV) biosorption under the condition of optimization. The experimental data are analyzed by using isotherm and kinetic models. Kinetic data follow the pseudo-second-order model and equilibrium data agree very well with the Langmuir model. In addition, FTIR analysis indicates that hydroxyl, amino, and carbonyl groups act as the important roles in the adsorption process.
Mostrar más [+] Menos [-]Mercury biomagnification in a contaminated estuary food web: Effects of age and trophic position using stable isotope analyses Texto completo
2013
Coelho, J.P. | Mieiro, C.L. | Pereira, E. | Duarte, A.C. | Pardal, M.A.
Mercury biomagnification in a contaminated estuary food web: Effects of age and trophic position using stable isotope analyses Texto completo
2013
Coelho, J.P. | Mieiro, C.L. | Pereira, E. | Duarte, A.C. | Pardal, M.A.
The main aim of this study was to ascertain the biomagnification processes in a mercury-contaminated estuary, by clarifying the trophic web structure through stable isotope ratios. For this purpose, primary producers (seagrasses and macroalgae), invertebrates (detritivores and benthic predators) and fish were analysed for total and organic mercury and for stable carbon and nitrogen isotopic signatures. Trophic structure was accurately described by δ15N, while δ13C reflected the carbon source for each species. An increase of mercury levels was observed with trophic level, particularly for organic mercury. Results confirm mercury biomagnification to occur in this estuarine food web, especially in the organic form, both in absolute concentrations and fraction of total mercury load. Age can be considered an important variable in mercury biomagnification studies, and data adjustments to account for the different exposure periods may be necessary for a correct assessment of trophic magnification rates and ecological risk.
Mostrar más [+] Menos [-]Mercury biomagnification in a contaminated estuary food web: effects of age and trophic position using stable isotope analyses Texto completo
1000 | 2013
Coelho, J. P. | Mieiro, C. L. | Pereira, E. | Duarte, A. C. | Pardal, M. A.
The main aim of this study was to ascertain the biomagnification processes in a mercury-contaminated estuary, by clarifying the trophic web structure through stable isotope ratios. For this purpose, primary producers (seagrasses and macroalgae), invertebrates (detritivores and benthic predators) and fish were analysed for total and organic mercury and for stable carbon and nitrogen isotopic signatures. Trophic structure was accurately described by δ15N, while δ13C reflected the carbon source for each species. An increase of mercury levels was observed with trophic level, particularly for organic mercury. Results confirm mercury biomagnification to occur in this estuarine food web, especially in the organic form, both in absolute concentrations and fraction of total mercury load. Age can be considered an important variable in mercury biomagnification studies, and data adjustments to account for the different exposure periods may be necessary for a correct assessment of trophic magnification rates and ecological risk.
Mostrar más [+] Menos [-]Spatial attribution of sulfate and dust aerosol sources in an urban area using receptor modeling coupled with Lagrangian trajectories Texto completo
2013
Chalbot, Marie–Cecile | Lianou, Maria | Vei, Ino–Christina | Kotronarou, Anastasia | Kavouras, Ilias G.
PM10 and PM2.5 (particles with diameter less than 10 μm and 2.5 μm, respectively) aerosol samples were collected from 2002 to 2004 in Athens, Greece and analyzed for elements ranging from Na to Pb using X–ray fluorescence. Positive matrix factorization (PMF) was applied to identify and quantify the types of PM10 and PM2.5 sources. The agreement between calculated and measured particle mass concentrations was very good for both aerosol fractions. Mineral soil, road dust and sea salt particles were the most significant types of coarse particles (PM10–2.5) while their contributions to PM2.5 fraction were minimal. Secondary sulfate, diesel particles from shipping and other oil combustion activities and primary traffic exhausts were determined as the most important types of PM2.5 sources. The analysis of normalized average air mass residence times showed weak seasonal patterns on the pathways of air masses prior to their arrival in Athens. Using trajectory regression analysis, the four adjacent regions (less than 500 km) accounted for the largest fraction of fine sulfate and diesel particles. On the contrary, shipping emissions and neutralization by sea salt may explain the high contributions of the regions covering the Mediterranean Sea and Dardanelle straights. The four adjacent regions and central Europe accounted for most of road and mineral dust particles. The transport from northern Africa over Mediterranean Sea also appeared to influence the mineral dust particles.
Mostrar más [+] Menos [-]Microplastic pollution in the surface waters of the Laurentian Great Lakes Texto completo
2013
Eriksen, Marcus | Mason, Sherri | Wilson, Stiv | Box, Carolyn | Zellers, Ann | Edwards, William | Farley, Hannah | Amato, Stephen
Neuston samples were collected at 21 stations during an ∼700 nautical mile (∼1300km) expedition in July 2012 in the Laurentian Great Lakes of the United States using a 333μm mesh manta trawl and analyzed for plastic debris. Although the average abundance was approximately 43,000 microplastic particles/km2, station 20, downstream from two major cities, contained over 466,000particles/km2, greater than all other stations combined. SEM analysis determined nearly 20% of particles less than 1mm, which were initially identified as microplastic by visual observation, were aluminum silicate from coal ash. Many microplastic particles were multi-colored spheres, which were compared to, and are suspected to be, microbeads from consumer products containing microplastic particles of similar size, shape, texture and composition. The presence of microplastics and coal ash in these surface samples, which were most abundant where lake currents converge, are likely from nearby urban effluent and coal burning power plants.
Mostrar más [+] Menos [-]Occurrence and distribution of heavy metals in surface sediments of the Changhua River Estuary and adjacent shelf (Hainan Island) Texto completo
2013
Hu, Bangqi | Cui, Ruyong | Li, Jun | Wei, Helong | Zhao, Jingtao | Bai, Fenglong | Song, Weiyu | Ding, Xue
Heavy metal (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) concentrations in surface sediments from the Changhua River Estuary and adjacent shelf, western Hainan Island, were conducted to evaluate the level of contamination. Numerical Sediment Quality Guidelines (TEL and PEL) were applied to assess adverse biological effects of these metals, suggesting that occasional biological effect may occur due to As, Cr, Cu, Ni, and Pb. Enrichment factors shown that the significant As and Pb contaminations in the study area. Multivariate analysis indicated that the sources of Cd, Cr, Cu, Hg, Ni and Zn resulted primarily from natural weathering processes, whereas As and Pb were mainly attributed to anthropogenic sources. The results of this study would provide a useful aid for sustainable marine management in the region.
Mostrar más [+] Menos [-]Detection of verotoxin producing Escherichia coli in marine environments of the Caribbean Texto completo
2013
Walker, Trisha J. | Bachoon, D.S. | Otero, Ernesto | Ramsubhag, Adesh
The goal of this study was to determine the potential for Enterohemorrhagic Escherichia coli O157:H7 (EHEC) contamination in tropical marine waters. Samples were collected from urban, suburban, and rural sites around the islands of Puerto Rico and The Republic of Trinidad and Tobago. Quantification of E. coli and EHEC was evaluated using MI plates and qPCR. EHEC was detected in six sites in Puerto Rico: West of La Parguera Town, Boquilla, Oro Creek, Fishers Association, Joyuda Lagoon, and Boqueron Wetland Creek and in two rural sites in Trinidad: Balandra Bay and Quinam Bay. Plate count enumeration of E. coli was not a reliable indicator for the presence of EHEC. The sites where EHEC was detected on both islands are used for recreational bathing, water sports and recreational/commercial fisheries and therefore pose a public potential health risk.
Mostrar más [+] Menos [-]Temporal changes in carbon and nitrogen stable isotope ratios of macrozoobenthos on an artificial tidal flat facing a hypertrophic canal, inner Tokyo Bay Texto completo
2013
Kanaya, Gen | Nakamura, Yasuo | Koizumi, Tomoyoshi | Yamada, Katsumasa | Koshikawa, Hiroshi | Kohzu, Ayato | Maki, Hideaki
Temporal changes in benthic food web structure were analyzed in an artificial tidal flat in inner Tokyo Bay, Japan, using carbon and nitrogen stable isotope ratios (δ13C and δ15N). Microphytobenthos were the most important food sources of macrozoobenthos, due to high microphytobenthic biomass on the tidal flat, while phytoplankton in canal water (canal POMPP), terrestrial materials from urban surface runoff (canal POMTM), and marsh plants were less important. Dietary contribution of microphytobenthos was highest in April to June, while decreased towards December owing to the supply of canal POMPP and canal POMTM following red tides and heavy rainfall events in summer to fall. Temporal changes in δ15N (Δδ15N) of consumer corresponded well to the 15N-enrichment in canal POMPP in summer. A meta-analysis showed that the consumer-Δδ15N was considerably larger in inner Tokyo Bay than those in other estuaries, which may be a specific characteristic of benthic food web in highly urbanized estuaries.
Mostrar más [+] Menos [-]Spatial distribution and historical input of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in sediments from a subtropical estuary (Guaratuba Bay, SW Atlantic) Texto completo
2013
Combi, Tatiane | Taniguchi, Satie | Figueira, Rubens Cesar Lopes | Mahiques, Michel Michaelovitch de | Martins, César C.
This study evaluated the occurrence and distribution of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in 22 surface sediment samples and one core collected in Guaratuba Bay, a large and well-preserved estuary in Southern Atlantic, Brazil. The concentration of PCBs in the superficial sediment samples ranged from <LQ (below the limit of quantification) to 5.62ngg−1, while the concentration of OCPs ranged from <LQ to 0.74ngg−1. The spatial distribution of the organochlorine compounds (OCs) suggested that the sources of these contaminants are located outside the bay and are related to human activities on the margins of the two main rivers that discharge in the region. The OCs in the sediment core ranged from <LQ to 0.52ngg−1 and from <LQ to 1.52ngg−1 for PCBs and OCPs, respectively. Despite their usage worldwide, the low concentrations of OCs in Guaratuba Bay suggest low input levels, which may represent the background levels for this region.
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