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Evidencing the natural and anthropogenic processes controlling trace metals dynamic in a highly stratified estuary: The Krka River estuary (Adriatic, Croatia) Full text
2015
Cindrić, Ana-Marija | Garnier, Cédric | Oursel, Benjamin | Pižeta, Ivanka | Omanović, Dario
Distributions of trace metals (TM), organic carbon, SPM and physico-chemical parameters were studied in the highly stratified Krka River estuary in winter/summer periods. The non-conservative behaviour of Zn, Cd, Pb and Cu in the brackish layer (plume), easily spotted due to very low inputs by the river, was mainly caused by their inputs from the pleasure boats, nautical marinas and harbour (e.g. release from antifouling paints). Contrarily, Ni and Co followed near-conservative behaviour. The extremely low SPM discharged by the river, resulted in a predominant dissolved fraction (>80%) of all TM, except Pb. Vertical scavenging, coupled with the long residence time, caused accumulation and progressive upstream increase of TM and SPM in the bottom seawater. Decrease of distribution coefficient (KD) in the brackish layer for winter period was ascribed to the change of SPM nature (terrestrial vs. biogenic), whereas a variable and increased biogenic component of SPM caused scattered KDs in summer.
Show more [+] Less [-]Microwave assisted catalytic removal of elemental mercury from flue gas using Mn/zeolite catalyst Full text
2015
Wei, Zaishan | Luo, Yuwei | Li, Baoren | Cheng, Zhouyang | Wang, Jianbin | Ye, Qihong
The integrated microwave with Mn/zeolite and ozone (MCO) and combined microwave with Mn/zeolite (MC) was employed to oxidize elemental mercury (Hg0) in simulated flue gas. The results show that mercury removal efficiency attained 35.3% in the MC, over 92% of Hg0 removal efficiency could be obtained in the MCO. The optimal microwave power and empty bed residence time (EBRT) in the microwave plasma catalytic oxidation were 264 W and 0.41 s, respectively. The effect of Hg0 oxidation in the MCO was much higher than that in the MC. Microwave accentuated catalytic oxidation of mercury, and increased mercury removal efficiency. The additional use of ozone to the microwave–catalysis over Mn/zeolite led to the enhancement of mercury oxidation. Mn/zeolite catalyst was characterized by X–ray diffraction (XRD), X–ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FT–IR), scanning electron microscopy (SEM) and the Brunauer Emmett Teller (BET) method. Microwave catalytic mercury over Mn/zeolite was dominated by a free radical oxidation route. Ozone molecules in air could enhance free radical formation. The coupling role between ozone and radicals on mercury oxidation in the MCO was formed. The MCO appears to be a promising method for emission control of elemental mercury.
Show more [+] Less [-]Mapping the Global Dust Storm Records: Review of Dust Data Sources in Supporting Modeling/Climate Study Full text
2015
Wang, Julian X. L.
Dust storms, as extreme environmental events, are one of the Earth’s major natural hazards. Their impact on socio-economics can range from local urban to (trans-) continental and from minutes to decades, such as the dust bowl of the 1930s in the United States. Research on dust storms can be traced back for several decades as a meteorological extension. Latest technology developments have enabled comprehensive studies on dust storms, including sampling improvement, analytic studies, and numerical modeling. However, inhomogeneity of the data has hampered and sometimes even misguided research on comprehensive understanding of dust storms and exploring their feedbacks with climate. This review will focus on currently available observations of dust activities, which include routine meteorological records, in situ air chemistry observations, and satellite remote sensing. The aim is to show data sources and the status of their usage in a common framework for global dust regions. Emphasis is placed on data continuity and the spatial and temporal coverage of dust storms, since it is anticipated that this brief summary of dust data will benefit modeling and climate studies. Therefore, it must be noted that field campaign data are outside of the scope of the current review, although they play an important role in research and understanding.
Show more [+] Less [-]Remediation of DDT and Its Metabolites in Contaminated Sediment Full text
2015
Chattopadhyay, Sandip | Chattopadhyay, Devamita
Chlorinated pesticides and chlorinated organics can be transformed or partially degraded in sediments under appropriate environmental conditions. Although 1,1,1-trichloro-2,2-bis[p-chlorophenyl]ethane (DDT) is very persistent in the environment, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), a degradation product of DDT, is generally the constituent most widely detected in the environment and DDE is also resistant to further biotransformation. DDT and its degradation products (DDTR) may be transported from one medium to another by sorption, bioaccumulation, dissolution, or volatilization. In sediments, DDT strongly adheres to suspended particles, but once metabolized, DDE, the primary product, is slightly soluble in water. The major migration process for DDTR in sediment-water systems is sorption to sediment or other organic matter and the primary distribution route is the transportation of the particulates to which the compound is bound. Understanding the fate and transport of DDTR in the natural environment based on its specific characteristics is important in determining appropriate remediation option. Common DDT-contaminated sediment remediation options include dredging, capping, and natural attenuation. Sediment washing and phytoremediation have also been used in contaminated sites. Dredging is the most common sediment remediation option to remove the contaminated benthic sediments but often suffers from technical limitations like incomplete removal, unfavorable site conditions, sediment resuspension, and disposal issues. Capping is an in situ, low-cost remediation option for immobilization of DDT in several contaminated sediment sites. Natural or anthropogenic materials containing reactive ingredients, as distinct from a conventional sand or gravel cap, involve placing reactive materials as part of the cap matrix to increase sorption, and to enhance chemical reactivity with DDTR, or accelerate degradation. Natural attenuation can treat the DDT-contaminated sediment, but the time frame for complete remediation may be relatively long. Addition of suitable co-metabolites and acclimatized microorganisms to DDTR-contaminated sediment and alteration of sediment-water micro-environment by manipulating soil pH, moisture content, and other chemical conditions may result in degradation of DDTR associated with sediments at rates faster than the natural attenuation rate.
Show more [+] Less [-]Pb, Cu and Cd distribution in five estuary systems of Marche, central Italy Full text
2015
Annibaldi, Anna | Illuminati, Silvia | Truzzi, Cristina | Libani, Giulia | Scarponi, Giuseppe
Heavy metals are subjected to monitoring in estuarine and marine water by the European Union Water Framework Directive, which requires water body health to be achieved by 2021. This is the first survey of heavy metals content in five estuaries of Marche, a region in central Italy. Results showed that total Pb and Cu concentrations decreased by 70–80%, from 1000–2000 to 100–200ngL−1 (Pb) and from 2000–3000 to 500–1000ngL−1 (Cu) from river to sea. Cd was consistently 20–40ngL−1. Dissolved Pb and Cu concentrations declined by 50% and 70% respectively passing from oligohaline to euhaline water, from 150 to 70ngL−1 and from 2000–1000 to 600–400ngL−1. Cd decreased slightly from ∼20 to ∼10ngL−1. Although such concentrations are in the range allowed by the Water Framework Directive, they far exceed (up to 10×) the ground content ceiling set for 2021.
Show more [+] Less [-]Meteorological driven changes on air quality over Portugal: a KZ filter application Full text
2015
Sá, Elisa | Tchepel, Oxana | Carvalho, Anabela | Borrego, C.
Meteorological driven changes on air quality over Portugal: a KZ filter application Full text
2015
Sá, Elisa | Tchepel, Oxana | Carvalho, Anabela | Borrego, C.
The Kolmogorov–Zurbenko (KZ) filter method is a tool to improve air quality management, since it determines meteorological effects on air quality concentrations and separates out those effects in order to examine underlying trends. Air quality in Portugal is exceeding the legislated particulate matter (PM10), nitrogen oxides (NO2) and ozone (O3) levels; accordingly, measures to reduce pollutant emissions have been designed. The primary objective of this work is to investigate the influence of meteorology on O3, NO2 and PM10 levels and the long-term air quality trends. Air quality and meteorological datasets were explored for the period 2002–2012 through the decomposition of time-series using the Kolmogorov–Zurbenko (KZ) filter. To determine the best meteorological predictors for the air quality data, a stepwise regression analysis of the filtered time-series was applied. The KZ filter application revealed that the short-term component has the highest contribution to the total variance of the original air quality data (≈64%–PM10; ≈52%–O3; ≈54%–NO2) followed by the seasonal component. The long-term component exhibits the influence of the emission control regulations implemented in each study region. The statistical analysis of the air quality and the meteorological data indicated that O3 has a statistically significant relationship with temperature in most of the components. The results also indicate that emission control strategies are primary regulators for NO2 and PM10 levels. Therefore, to establish an accurate strategy to improve air quality further, it will be essential to include meteorological effects. This study highlights that the KZ filter is a useful tool to support the design and implementation of adequate air quality strategies and for the investigation of the interactions between the emissions, the meteorological conditions and the air quality levels, to improve air quality management in these two urban areas.
Show more [+] Less [-]Meteorological driven changes on air quality over Portugal: a KZ filter application Full text
1000 | 2015
Sa, Elisa | Tchepel, Oxana | Carvalho, Anabela | Borrego, Carlos
The KolmogoroveZurbenko (KZ) filter method is a tool to improve air quality management, since it determines meteorological effects on air quality concentrations and separates out those effects in order to examine underlying trends. Air quality in Portugal is exceeding the legislated particulate matter (PM10), nitrogen oxides (NO2) and ozone (O3) levels; accordingly, measures to reduce pollutant emissions have been designed. The primary objective of this work is to investigate the influence of meteorology on O3, NO2 and PM10 levels and the long-term air quality trends. Air quality and meteorological datasets were explored for the period 2002e2012 through the decomposition of time-series using the KolmogoroveZurbenko (KZ) filter. To determine the best meteorological predictors for the air quality data, a stepwise regression analysis of the filtered time-series was applied. The KZ filter application revealed that the short-term component has the highest contribution to the total variance of the original air quality data (z64%ePM10; z52%eO3; z54%eNO2) followed by the seasonal component. The longterm component exhibits the influence of the emission control regulations implemented in each study region. The statistical analysis of the air quality and the meteorological data indicated that O3 has a statistically significant relationship with temperature in most of the components. The results also indicate that emission control strategies are primary regulators for NO2 and PM10 levels. Therefore, to establish an accurate strategy to improve air quality further, it will be essential to include meteorological effects. This study highlights that the KZ filter is a useful tool to support the design and implementation of adequate air quality strategies and for the investigation of the interactions between the emissions, the meteorological conditions and the air quality levels, to improve air quality management in these two urban areas.
Show more [+] Less [-]Levels of metals, arsenic and phosphorus in sediments from two sectors of a Brazilian Marine Protected Area (Tupinambás Ecological Station) Full text
2015
Hoff, Natasha T. | Figueira, Rubens C.L. | Abessa, Denis M.S.
The Tupinambás Ecological Station (TES) is a Marine Protected Area consisting of two sectors: the Archipelago of Alcatrazes and the Cabras and Palmas islets. This investigation aimed to provide a first diagnosis of the concentrations of metals (Al,Cr,Cu,Fe,Hg,Ni,Pb,Zn), As and P in sediments from the TES. 24 sediment samples were collected in both sectors using a Van Veen grab sampler. Sediment textures and levels of Organic Matter (OM) and CaCO3 were determined, as well as the concentrations of the above-mentioned elements after partial acid digestion. Sediments were predominantly sandy. Higher levels of CaCO3 occurred in the Alcatrazes sector, whereas the OM contents were higher in the islets sector. Metals concentrations were low and associated with fines, while P and As presented a different behavior. The observed concentrations to all studies elements in sediments from the TES were considered as background values.
Show more [+] Less [-]Cetacean noise criteria revisited in the light of proposed exposure limits for harbour porpoises Full text
2015
Tougaard, Jakob | Wright, Andrew J. | Madsen, Peter T.
The impact of underwater noise on marine life calls for identification of exposure criteria to inform mitigation. Here we review recent experimental evidence with focus on the high-frequency cetaceans and discuss scientifically-based initial exposure criteria. A range of new TTS experiments suggest that harbour and finless porpoises are more sensitive to sound than expected from extrapolations based on results from bottlenose dolphins. Furthermore, the results from TTS experiments and field studies of behavioural reactions to noise, suggest that response thresholds and TTS critically depend on stimulus frequency. Sound exposure levels for pure tones that induce TTS are reasonably consistent at about 100dB above the hearing threshold for pure tones and sound pressure thresholds for avoidance reactions are in the range of 40–50dB above the hearing threshold. We propose that frequency weighting with a filter function approximating the inversed audiogram might be appropriate when assessing impact.
Show more [+] Less [-]Characterization and activity of N doped TiO2 supported VPO catalysts for NO oxidation Full text
2015
Jia, Yong | Du, Daqian | Bai, Jiachuan | Ding, Jie | Zhong, Qin | Ding, Xilou
Nitrogen (N) doped TiO2 supported vanadium phosphorus oxide (VPO) catalysts were prepared and tested for catalytic oxidation of NO. The experimental results showed that 0.1V(5)PO/TiN(1) was the optimal catalyst for NO oxidation and the NO conversion could reach 61% at temperature of 350°C. The physico–chemical properties of 0.1V(5)PO/TiN(1) catalyst were characterized by Brunauer–Emmett–Teller measurements (BET), Photoluminescence (PL), X–ray photoelectron spectroscopy (XPS), Infrared spectroscopy measurements of NH3 adsorbed on catalysts (NH3–IR), and Infrared Fourier transform spectroscopy (FTIR). The PL and XPS spectra revealed that the oxygen storage capacity and catalytic activity of VPO/Ti catalyst can be improved by nitrogen doping. The H2–TPR profile also indicated that V(5)PO/TiN(1) catalyst had a superior redox property. Activity test results and FTIR spectra showed that 0.1V(5)PO/TiN(1) catalysts had a superior resistivity to SO2 and the NO oxidation rate is above 50% at temperature of 350°C when SO2 concentration is 200ppm to 800ppm.
Show more [+] Less [-]Polycyclic aromatic hydrocarbons in surface sediment from Yangpu Bay, China: Distribution, sources and risk assessment Full text
2015
Li, Ping | Diao, Xiaoping | Zhang, Yu | Xie, Yanli | Yang, Fei | Zhou, Hailong | Han, Qian | Wang, Fuqiang | Cheng, Huamin | Wang, Haihua
The study investigated the occurrence of polycyclic aromatic hydrocarbons (PAHs) in the surface sediment from eleven sites in Yangpu Bay, China in December 2013 (winter) and July 2014 (summer). The 16 US EPA priority PAHs were found in the range of 1583.2–5701.7ng/g dry weights with an average of 3134.7±1241.3ng/g in winter and ranged from 2161.8 to 4527.2ng/g with an average of 3016.6±748.0ng/g in summer, respectively. The concentrations of the PAHs tended to be relatively high in comparison with other areas from the literatures. The identification using molecular indices analysis indicated that the PAHs originated mainly from pyrogenic and petrogenic sources in most of the sites. According to principle component analysis–multiple linear regression (PCA/MLR) for their source apportionment, the main sources of PAHs were vehicle emissions, petroleum products and biomass combustion. The risk assessment using international sediments quality guidelines and sediments quality criteria indicated that several PAHs, such as Nap, Flu, Phe, Ace, Acy and BghiP in most of the sites would potentially affect organisms in Yangpu Bay.
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