Refine search
Results 501-510 of 1,955
Investigations on the impact of single direct and indirect, and multiple emission–control measures on cold–season near–surface PM2.5 concentrations in Fairbanks, Alaska Full text
2013
Mölders, Nicole
The impact of two direct (wood–burning device changeout, introduction of gas), an indirect (introduction of low–sulfur fuel) and a multiple (wood–burning device changeout plus introduction of low–sulfur fuel) emission control measure on near surface PM2.5 concentrations in Fairbanks, Alaska was examined for a cold season by WRF/Chem simulations and the 2008/09 hourly observations. The benefits for air quality would vary in persistence and the diurnal course among measures. None of these emission control measures would provide design values below the National Ambient Air Quality Standard (35µg m–3). Substituting all wood–burning by gas would reduce PM2.5 emissions by ~11% and the 2008 design value of 44.7µg m–3 to 38.9µg m–3. The estimated ~4% PM2.5 emission decrease due to changeout of noncertified by certified wood–burning devices would reduce the design value to 42.3µg m–3. The use of low–sulfur fuel in oil–fired furnaces and facilities would reduce total SO2 and PM2.5 emissions by ~23 and 15%, respectively, but provide a similar design value. The multiple emission control measure would reduce these emissions by ~36 and 19%, respectively, and the design value to 39.3µg m–3. The indirect emission control measure is most sensitive to meteorology. The efficiency of the multiple emission control measures is not generally the sum of the efficiency of the respective single measures.
Show more [+] Less [-]Distribution and sources of polycyclic aromatic hydrocarbons in Cilician Basin shelf sediments (NE Mediterranean) Full text
2013
This study corresponds to preliminary work representing an initial assessment for spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in the Cilician Basin coastal sediments. The concentrations of PAHs in shelf sediments were determined from the three different regions of Cilician Basin (Eastern Mediterranean) in 2011. Concentrations of PAHs were low 5.43–271ngg−1 with respect to other coastal sediments in the Mediterranean and these results could be compared with concentrations found in open sea areas. PAH composed mainly of pyrolytic four and five-ring compounds. An abundance of high molecular weight PAHs indicated that atmospheric particles and urban aerosols are the major input route of hydrocarbons in the Cilician and Lattakia Basins. PAH levels were assessed in accordance with numerical Sediment Quality Guideline (SQG) of the USEPA. The results showed that no samples exceeded biological thresholds to pose biological impairments.
Show more [+] Less [-]Bacteria associated with sabellids (Polychaeta: Annelida) as a novel source of surface active compounds Full text
2013
(Emilio),
A total of 69 bacteria were isolated from crude oil enrichments of the polychaetes Megalomma claparedei, Sabella spallanzanii and Branchiomma luctuosum, and screened for biosurfactant (BS) production by conventional methods. Potential BS-producers (30 isolates) were primarily selected due to the production of both interesting spots on thin layer chromatography (TLC) plates and highly stable emulsions (E24⩾50%). Only few strains grew on cetyltrimethylammonium bromide and blood agar plates, indicating the probable production of anionic surfactants. The 16S rRNA gene sequencing revealed that selected isolates mainly belonged to the CFB group of Bacteroidetes, followed by Gammaproteobacteria and Alphaproteobacteria.A number of BS-producers belonged to genera (i.e., Cellulophaga, Cobetia, Cohaesibacter, Idiomarina, Pseudovibrio and Thalassospira) that have been never reported as able to produce BSs, even if they have been previously detected in hydrocarbon-enriched samples. Our results suggest that filter-feeding Polychaetes could represent a novel and yet unexplored source of biosurfactant-producing bacteria.
Show more [+] Less [-]Kinetics of the PO4-P adsorption onto soils and sediments from the Mondego estuary (Portugal) Full text
2013
Otero, M. | Coelho, J.P. | Rodrigues, E.T. | Pardal, M.A. | Santos, E.B.H. | Esteves, V.I. | Lillebø, A.I.
Kinetics of the PO4-P adsorption onto soils and sediments from the Mondego estuary (Portugal) Full text
2013
Otero, M. | Coelho, J.P. | Rodrigues, E.T. | Pardal, M.A. | Santos, E.B.H. | Esteves, V.I. | Lillebø, A.I.
In order to assess the status of a North Atlantic Ocean Ecoregion (Mondego system, Portugal) after the implementation of a management programme, a study on PO4-P sorption was carried out. Considering that sorption velocity markedly determines the systems promptness to phosphorus external loading, the kinetics of the sorption of PO4-P onto estuarine sediments and the upstream agricultural soils was studied. The pseudo-second order kinetic equation gave an appropriate description of PO4-P sorption onto these soils and sediments, allowing for a quantitative comparison. For soils, the kinetic constants (k2⁎, μg−1gh−1) ranged between 0.007 and 0.017μg−1gh−1 while, in the case of sediments these ranged between 0.008 and 0.012μg−1gh−1. Results showed that the reduction of water residence time after the management action was relevant for the system status, affecting its reaction capacity to phosphorus loading.
Show more [+] Less [-]Kinetics of the PO4-P adsorption onto soils and sediments from the Mondego estuary (Portugal) Full text
2013
Otero, M. | Coelho, J. P. | Rodrigues, E. T. | Pardal, M. A. | Santos, E. B. H. | Esteves, V. I. | Lillebø, A. I.
In order to assess the status of a North Atlantic Ocean Ecoregion (Mondego system, Portugal) after the implementation of a management programme, a study on PO4-P sorption was carried out. Considering that sorption velocity markedly determines the systems promptness to phosphorus external loading, the kinetics of the sorption of PO4-P onto estuarine sediments and the upstream agricultural soils was studied. The pseudo-second order kinetic equation gave an appropriate description of PO4-P sorption onto these soils and sediments, allowing for a quantitative comparison. For soils, the kinetic constants (k2*, μg-1gh-1) ranged between 0.007 and 0.017μg-1gh-1while, in the case of sediments these ranged between 0.008 and 0.012μg-1gh-1. Results showed that the reduction of water residence time after the management action was relevant for the system status, affecting its reaction capacity to phosphorus loading. | The authors want to acknowledge financial support from FCT (Fundação para a Ciência e a Tecnologia) to CESAM (Centre for Environmental and Marine Studies) and to IMAR (Institute of Marine Research). The Post-Doc grant SFRH/BPD/48449/2008 (P. Coelho) funded by FCT is also acknowledged. Also, Marta Otero acknowledges support from the Spanish Ministry of Science and Innovation (RYC-2010-05634). Special thanks are given go to Dr José Raposo for drawing Fig. 1. | published
Show more [+] Less [-]Looking at the aquatic contamination through fish eyes – A faithful picture based on metals burden Full text
2013
Pereira, Patrícia | Raimundo, Joana | Canário, João | Almeida, Armando | Pacheco, Mario
Looking at the aquatic contamination through fish eyes – A faithful picture based on metals burden Full text
2013
Pereira, Patrícia | Raimundo, Joana | Canário, João | Almeida, Armando | Pacheco, Mario
This study describes for the first time metal accumulation in the eyes of native golden grey mullet (Liza aurata) coupled with water/sediment quality assessment. Sampling was performed in the Tagus estuary (Portugal) where a confined area (Barreiro) is severely contaminated by metal/loids. Levels of As, Cu, Pb, Hg and Cd in sediments from Barreiro were one order of magnitude higher than those from the reference site. Data on water column pointed also to a higher availability of Cu, Pb, Cd and Hg (including MeHg) at Barreiro. Accordingly, fish eyes accumulated higher levels of metal/loids at Barreiro than at the reference site. These findings support the use of fish eyes as a target organ in environmental health assessment since they reflect sediment and water contamination. It points also to the importance of evaluate eye changes at structural/functional levels in order to examine in what extent accumulated metals could compromise this perceptive system.
Show more [+] Less [-]Looking at the aquatic contamination through fish eyes - a faithful picture based on metals burden Full text
2013
Pereira, Patrícia | Raimundo, Joana | Canário, João | Almeida, Armando | Pacheco, Mário
This study describes for the first time metal accumulation in the eyes of native golden grey mullet (Liza aurata) coupled with water/sediment quality assessment. Sampling was performed in the Tagus estuary (Portugal) where a confined area (Barreiro) is severely contaminated by metal/loids. Levels of As, Cu, Pb, Hg and Cd in sediments from Barreiro were one order of magnitude higher than those from the reference site. Data on water column pointed also to a higher availability of Cu, Pb, Cd and Hg (including MeHg) at Barreiro. Accordingly, fish eyes accumulated higher levels of metal/loids at Barreiro than at the reference site. These findings support the use of fish eyes as a target organ in environmental health assessment since they reflect sediment and water contamination. It points also to the importance of evaluate eye changes at structural/functional levels in order to examine in what extent accumulated metals could compromise this perceptive system. | Patrícia Pereira (SFRH/BPD/69563/2010) and Joana Raimundo (SFRH/BPD/91498/2012) benefit from Pos-doctoral grants supported by “Fundação para a Ciência e a Tecnologia” (FCT). This work as been supported by the following projects also funded by FCT: NEUTOXMER “Neurotoxicity of mercury in fish and association with morphofunctional brain alterations and behavior shifts” (PTDC/AAG-REC/2488/2012) and PROFLUX “Processes and fluxes of mercury and methylmercury in a contaminated coastal ecosystem Tagus Estuary, Portugal” (PTDC/MAR/102748/2008). Authors wish to acknowledge Bárbara Anes and Rute Cesário for the fish sampling support. | published
Show more [+] Less [-]Contaminants assessment in the coral reefs of Virgin Islands National Park and Virgin Islands Coral Reef National Monument Full text
2013
Bargar, Timothy A. | Garrison, Virginia H. | Alvarez, David A. | Echols, Kathy R.
Coral, fish, plankton, and detritus samples were collected from coral reefs in Virgin Islands National Park (VIIS) and Virgin Islands Coral Reef National Monument (VICR) to assess existing contamination levels. Passive water sampling using polar organic chemical integrative samplers (POCIS) and semi-permeable membrane devices found a few emerging pollutants of concern (DEET and galaxolide) and polynuclear aromatic hydrocarbons. Very little persistent organic chemical contamination was detected in the tissue or detritus samples. Detected contaminants were at concentrations below those reported to be harmful to aquatic organisms. Extracts from the POCIS were subjected to the yeast estrogen screen (YES) to assess potential estrogenicity of the contaminant mixture. Results of the YES (estrogen equivalency of 0.17–0.31ng/L 17-β-estradiol) indicated a low estrogenicity likelihood for contaminants extracted from water. Findings point to low levels of polar and non-polar organic contaminants in the bays sampled within VICR and VIIS.
Show more [+] Less [-]Baseline occurrence of organochlorine pesticides and other xenobiotics in the marine environment: Caribbean and Pacific collections Full text
2013
Menzies, Robert | Soares Quinete, Natalia | Gardinali, Piero | Seba, Douglas
This ongoing survey reports the levels of persistent organic pollutants (POPs) in sea surface slicks collected on a global circumnavigation. Hydrophobic xenobiotic compounds such as POPs are known to accumulate on the sea surface in slicks at concentrations many fold greater than the underlying water column, raising concerns about the ecological impacts due to the high biological activity associated with this zone. Six different categories of POPs were reported: chlorobenzenes, hexachlorocyclohexanes, chlordane related compounds, organochlorine pesticides and other cyclodiene pesticides, DDTs and metabolites, and polychlorinated biphenyls. Concentrations ranged from <1ngL−1 to 18.45μgL−1. Ranking analysis indicates an independence of detected concentrations for each class of compounds and their geographical locations. Although concentrations observed were normally low and below commonly accepted toxic levels to animals and humans, they fall within the effective range of concentrations of many hormones and neurotransmitters, thus could potentially act as endocrine disrupters.
Show more [+] Less [-]Corals from the Persian/Arabian Gulf as models for thermotolerant reef-builders: Prevalence of clade C3 Symbiodinium, host fluorescence and ex situ temperature tolerance Full text
2013
Hume, B. | D’Angelo, C. | Burt, J. | Baker, A.C. | Riegl, B. | Wiedenmann, J.
Corals in the Arabian/Persian Gulf endure summer temperatures of up to 36°C, making them ideal subjects to study the mechanisms underlying thermal tolerance. Unexpectedly, we found the “generalist” Symbiodinium clade C3 to be the prevalent symbiont among seven coral species from Abu Dhabi (UAE) waters. Moreover, C3 represented the only dominant symbiont type in Porites spp. from this region. The “thermotolerant” symbionts D1a and C15 were not encountered, indicating that the association with these symbionts cannot be the sole reason for the heat tolerance of Gulf corals. The association of Porites lobata with specific symbiont types (C3 vs. C15) in samples from habitats with very different temperature regimes (Abu Dhabi vs. Fiji) remained unaffected by laboratory culture. During temperature stress experiments specimens from both locations strongly downregulated green fluorescent protein (GFP)-like pigments. However, the Abu Dhabi samples were less prone to bleaching and showed lower mortality.
Show more [+] Less [-]Concentration profiles of PCB congeners in the blubber and liver of Steller sea lions (Eumetopias jubatus) from the coast of Hokkaido, Japan Full text
2013
Kubo, Keiko | Yamaguchi, Katsuyuki | Mitsuhashi, Masaki | Hattori, Kaoru | Tanaka, Shunitz
The concentrations of PCB congeners in the blubber and liver of male and female Steller sea lions (Eumetopias jubatus; SSLs) collected from the Shakotan Peninsula and the Nemuro Strait, Hokkaido, Japan in 2008 and 2010 were measured by HRGC–HRMS, in order to express the concentration profiles in SSLs at these regions. #153 predominated in both organs, followed by #138, #99 and #118. In males, #28 and #31 were concentrated particularly in the blubber, while #177 and #199 were accumulated specifically in the liver. The differences in these concentration profiles might be expressed by the differences in the organs and their functions. The concentrations of #99, #118, #138, #153, and #180 in the blubber appeared to correspond significantly with the differences between genders. The details of the surveys on PCB congeners in SSLs could clarify the differences in the residue levels of individual congeners for organs and genders.
Show more [+] Less [-]Occurrence, distribution, and bioaccumulation of antibiotics in coastal environment of Dalian, China Full text
2013
Na, Guangshui | Fang, Xiaodan | Cai, Yaqi | Ge, Linke | Zong, Humin | Yuan, Xiutang | Yao, Ziwei | Zhang, Zhifeng
Seawater, sediment, and aquatic organism samples were collected from 20 sampling sites in coastal environment of Dalian in August, 2011. The occurrence, distribution, and bioaccumulation of 20 antibiotics categorizing into three groups, including 14 sulfonamides (SAs), two chloramphenicols (CAPs) and four tetracyclines (TCs), were investigated. The results suggested that tetracyclines were the predominant antibiotics in the seawater (range: 2.11–9.23ngL−1), while sulfonamides were the dominant antibiotics in both sediments (range: 1.42–71.32μgkg−1) and aquatic organisms (range: 2.18–63.87μgkg−1). The sorption coefficient Kd,s values revealed that sulfameter, sulfadiazine, sulfamethoxypyridazine, sulfamonomethoxine, chloramphenicol, and doxycycline presented higher sorption capacities than the other antibiotics. The average BAFs suggested that sulfamethazine, sulfamethiazole, sulfamonomethoxine, and doxycycline were potentially bioaccumulative, while sulfadiazine, sulfameter, sulfamethoxypyridazine, and chloramphenicol were bioaccumulative.
Show more [+] Less [-]