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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
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 [-]Evaluation of autochthonous bioaugmentation and biostimulation during microcosm-simulated oil spills
2013
Nikolopoulou, M. | Pasadakis, N. | Kalogerakis, N.
Oil spills are treated as a widespread problem that poses a great threat to any ecosystem. Following first response actions, bioremediation has emerged as the best strategy for combating oil spills and can be enhanced by the following two complementary approaches: bioaugmentation and biostimulation. Bioaugmentation is one of the most controversial issues of bioremediation. Studies that compare the relative performance of bioaugmentation and biostimulation suggest that nutrient addition alone has a greater effect on oil biodegradation than the addition of microbial products because the survival and degradation ability of microbes introduced to a contaminated site are highly dependent on environmental conditions. Microbial populations grown in rich media under laboratory conditions become stressed when exposed to field conditions in which nutrient concentrations are substantially lower. There is increasing evidence that the best approach to overcoming these barriers is the use of microorganisms from the polluted area, an approach proposed as autochthonous bioaugmentation (ABA) and defined as a bioaugmentation technology that exclusively uses microorganisms indigenous to the sites (soil, sand, and water) slated for decontamination. In this work, we examined the effectiveness of strategies combining autochthonous bioaugmentation with biostimulation for successful remediation of polluted marine environments. Seawater was collected from a pristine area (Agios Onoufrios Beach, Chania) and was placed in a bioreactor with 1% v/v crude oil to facilitate the adaptation of the indigenous microorganism population. The pre-adapted consortium and the indigenous population were tested in combination with inorganic or lipophilic nutrients in the presence (or absence) of biosurfactants (rhamnolipids) during 90-day long experiments. Chemical analysis (gas chromatography–mass spectrometry) of petroleum hydrocarbons confirmed the results of previous work demonstrating that the biodegradation processes were enhanced by the addition of lipophilic fertilizers (uric acid and lecithin) in combination with biosurfactants (rhamnolipids), resulting in increased removal of petroleum hydrocarbons as well as reduction of the lag phase within 15days of treatment. Considering this outcome and examining the results, the use of biostimulation additives in combination with naturally pre-adapted hydrocarbon-degrading consortia (bioaugmentation) has proved to be an effective treatment and is a promising strategy that could be applied specifically when an oil spill approaches near a shore line and an immediate hydrocarbon degradation effort is needed.
Show more [+] Less [-]Drivers of estuarine benthic species distribution patterns following a restoration of a seagrass bed: A functional trait analyses
2013
Dolbeth, Marina | Cardoso, Patricia | Grilo, Tiago | Raffaelli, Dave | Pardal, Miguel Ângelo
We integrate information on functional diversity (FD) patterns from estuarine intertidal benthic communities from different habitats and along a temporal disturbance gradient, to understand the drivers of species coexistence patterns. Species and traits’ biomass levels seemed to be first determined by habitat filtering, selecting those traits better adapted to the biologically challenging estuarine environment. Within that subset of traits and within each habitat, biotic interactions were probably high, as evidenced by high α-diversity and community weighted mean differences. The former patterns hold for the disturbance/recovery scenario considered. However, as the estuary recovered, biomass became more distributed among different trait categories, consistent with increases in FD when the seagrass started to increase. Policy towards the restoration of seagrass bed and other biogenic structures, and improving the connectivity within adjacent systems were confirmed and suggested, as this would imply higher FD and potentially higher resilience to disturbance within the estuarine intertidal system.
Show more [+] Less [-]Carbon and nitrogen stable isotope ratios and mercury concentration in the scalp hair of residents from Taiji, a whaling town
2013
Endo, Tetsuya | Hayasaka, Moriaki | Hisamichi, Yohsuke | Kimura, Osamu | Haraguchi, Koichi
We analyzed stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) as well as mercury (Hg) concentration in the scalp hair of Japanese who consumed whale meat and those who did not, and investigated the relationships among the δ13C and δ15N values and Hg concentration. The average δ15N and δ13C values of whale meat-eaters (10.11‰ and −18.5‰) were significantly higher than those of non-eaters (9.28‰ and −18.9‰), respectively. The average Hg concentration of whale meat-eaters (20.6μg/g) was significantly higher than that of non-eaters (2.20μg/g). Significant positive correlations were found between the δ13C and δ15N values and between the δ15N value and Hg concentration in the hair of whale meat-eaters, while the correlation between the δ15N value and Hg concentration was not statistically significant in the non-eaters. The consumption of whale meat may increase Hg concentration as well as δ15N and δ13C values in scalp hair.
Show more [+] Less [-]Estimating sub-surface dispersed oil concentration using acoustic backscatter response
2013
Fuller, Christopher B. | Bonner, James S. | Islam, Mohammad S. | Page, Cheryl | Ojo, Temitope | Kirkey, William
The recent Deepwater Horizon disaster resulted in a dispersed oil plume at an approximate depth of 1000m. Several methods were used to characterize this plume with respect to concentration and spatial extent including surface supported sampling and autonomous underwater vehicles with in situ instrument payloads. Additionally, echo sounders were used to track the plume location, demonstrating the potential for remote detection using acoustic backscatter (ABS). This study evaluated use of an Acoustic Doppler Current Profiler (ADCP) to quantitatively detect oil-droplet suspensions from the ABS response in a controlled laboratory setting. Results from this study showed log-linear ABS responses to oil-droplet volume concentration. However, the inability to reproduce ABS response factors suggests the difficultly in developing meaningful calibration factors for quantitative field analysis. Evaluation of theoretical ABS intensity derived from the particle size distribution provided insight regarding method sensitivity in the presence of interfering ambient particles.
Show more [+] Less [-]Tracing organic matter removal in polluted coastal waters via floating bed phytoremediation
2013
Huang, Lingfeng | Zhuo, Jianfu | Guo, Weidong | Spencer, Robert G.M. | Zhang, Zhiying | Xu, Jing
Organic matter removal by cultured Sesuvium portulacastrum in constructed floating beds was studied during a 20day greenhouse experiment and an 8month field campaign in the polluted Yundang Lagoon (southeastern China). Experiments were traced via dissolved organic carbon (DOC) concentration, fluorescence excitation–emission matrix and absorption spectroscopy. Two ‘terrestrial’ humic-like, one ‘marine’ humic-like and one protein-like components were identified by parallel factor analysis. The ‘terrestrial’ humic-like and protein-like components, DOC and absorption coefficient (a280) decreased during the greenhouse experiment. The intensities of four fluorescence components were all reduced during the field experiment. These results demonstrate the clear potential of floating bed phytoremediation techniques for reducing organic pollution degree in brackish environments. The rhizosphere may play an important role during phytoremediation. Our results show that spectrophotometric measurements such as fluorescence provide a useful tool for examining the removal of different organic moieties during various bioremediation processes.
Show more [+] Less [-]Sedimentary PBDEs in urban areas of tropical Asian countries
2013
Kwan, Charita S. | Takada, Hideshige | Mizukawa, Kaoruko | Saha, Mahua | Rinawati, | Santiago, Evangeline C.
Polybrominated diphenyl ethers (PBDEs) were measured in surface sediment samples collected from urban canals or rivers in Lao PDR, Cambodia, Vietnam, India, Indonesia, Thailand, the Philippines, Malaysia and Japan. The total PBDE concentrations in the sediments ranged from 0.83 to 3140ng/g dry wt. BDE-209 was predominant, ranging from 43% to 97% of total PBDEs, followed by nona-BDEs and some detectable concentrations of BDEs 47, 49, 99, 100, 153, 154 and 183. Sedimentary PBDE levels in Malaysia, Cambodia, the Philippines and Thailand were generally higher than those reported for highly industrialized countries. Spatial distribution of PBDEs indicated that inland sources may impact coastal areas. The presence of BDE congeners which are not contained in technical mixtures and the higher proportions of nona-BDEs relative to BDE-209 in the sediments were identified as indicators of debromination. BDE-209 was possibly debrominated under anaerobic conditions in some of the sediment samples.
Show more [+] Less [-]Good Environmental Status of marine ecosystems: What is it and how do we know when we have attained it?
2013
Borja, Angel | Elliott, Mike | Andersen, Jesper H. | Cardoso, Ana C. | Carstensen, Jacob | Ferreira, João G. | Heiskanen, Anna-Stiina | Marques, João C. | Neto, João M. | Teixeira, Heliana | Uusitalo, Laura | Uyarra, María C. | Zampoukas, Nikolaos
The European Marine Strategy Framework Directive (MSFD) requires EU Member States (MS) to achieve Good Environmental Status (GEnS) of their seas by 2020. We address the question of what GEnS entails especially with regard to the level at which targets are set (descriptors, criteria, indicators), to scales for assessments (regional, sub-divisions, site-specific), and to difficulties in putting into practice the GEnS concept. We propose a refined and operational definition of GEnS, indicating the data and information needed to all parts of that definition. We indicate the options for determining when GEnS has been met, acknowledge the data and information needs for each option, and recommend a combination of existing quantitative targets and expert judgement. We think that the MSFD implementation needs to be less complex than shown for other similar directives, can be based largely on existing data and can be centred on the activities of the Regional Seas Conventions.
Show more [+] Less [-]Spatial attribution of sulfate and dust aerosol sources in an urban area using receptor modeling coupled with Lagrangian trajectories
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.
Show more [+] Less [-]Dispersion model evaluation of PM2.5, NOx and SO2 from point and major line sources in Nova Scotia, Canada using AERMOD Gaussian plume air dispersion model
2013
Gibson, Mark D. | Kundu, Soumita | Satish, Mysore
AERMOD was used to model the air dispersion of point and major line emissions of PM2.5 in Halifax and Pictou, NOX in Halifax and SO2 in Halifax, Sydney and Port Hawkesbury, Nova Scotia, Canada. Emission inventory data for 2004 were used in simulations within four, 50 km x 50 km, domains over annual, monthly and 1–hour averaging periods. Annual averaged surface concentration maps are reported. Modeled versus observed comparisons were made within each domain at the Government, National Air Pollution Surveillance (NAPS) monitoring sites (discrete receptors). Evaluation of the model was conducted on the annual, monthly and hourly results using a number of statistical methods that included R2, fractional bias, normalized mean square error and the fraction of predictions within a factor of two of the observations. The AERMOD model evaluation showed that there was good agreement between the modeled and observed SO2 concentration for the annual and monthly comparison but less skill at estimating the hourly comparisons for SO2 in Halifax and Sydney. AERMOD showed poor model skill at predicting SO2 in Port Hawkesbury over the same averaging periods. The model evaluation for PM2.5 in Halifax, PM2.5 in Pictou and NOX in Halifax showed poor agreements and model skill. The surface concentrations from the point and major lines sources in all domains from all metrics were found to be well below the National Air Quality Standards. AERMOD has shown its utility as a suitable model for conducting dispersion modeling from point and line sources in Nova Scotia with good model skill for estimating annual and monthly SO2 concentrations in Halifax and Sydney. The study highlights the validity of using emission inventory data to estimate the surface impact of major point and line sources within domains containing complex terrain, differing land use types and with large variability within the annual meteorology.
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