WorldWideScience

Sample records for analysis atmospheric deposition

  1. Sampling of Atmospheric Precipitation and Deposits for Analysis of Atmospheric Pollution

    OpenAIRE

    J. Namieśnik; K. Skarżyńska; Ż Polkowska

    2006-01-01

    This paper reviews techniques and equipment for collecting precipitation samples from the atmosphere (fog and cloud water) and from atmospheric deposits (dew, hoarfrost, and rime) that are suitable for the evaluation of atmospheric pollution. It discusses the storage and preparation of samples for analysis and also presents bibliographic information on the concentration ranges of inorganic and organic compounds in the precipitation and atmospheric deposit samples.

  2. Atmospheric heavy metal deposition in Europe estimated by moss analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ruehling, Aa. [Swedish Environmental Research Inst., Lund (Sweden). Dept. of Ecology

    1995-12-31

    Atmospheric heavy metal deposition in Europe including 21 countries was monitored in 1990-1992 by the moss technique. This technique is based on the fact that the concentrations of heavy metals in moss are closely correlated to atmospheric deposition. This was the first attempt to map heavy metal deposition in this large area. The objectives of the project were to characterise qualitatively and quantitatively the regional atmospheric deposition pattern of heavy metals in background areas in Europe, to indicate the location of important heavy metal pollution sources and to allow retrospective comparisons with similar studies. The present survey is a follow-up of a joint Danish and Swedish project in 1980 and an extended survey in 1985 within the framework of the Nordic Council of Ministers. In Sweden, heavy-metal deposition was first mapped on a nation-wide scale in 1968-1971 and 1975. (author)

  3. Glacial atmospheric phosphorus deposition

    Science.gov (United States)

    Kjær, Helle Astrid; Dallmayr, Remi; Gabrieli, Jacopo; Goto-Azuma, Kumiko; Hirabayashi, Motohiro; Svensson, Anders; Vallelonga, Paul

    2016-04-01

    Phosphorus in the atmosphere is poorly studied and thus not much is known about atmospheric phosphorus and phosphate transport and deposition changes over time, though it is well known that phosphorus can be a source of long-range nutrient transport, e.g. Saharan dust transported to the tropical forests of Brazil. In glacial times it has been speculated that transport of phosphorus from exposed shelves would increase the ocean productivity by wash out. However whether the exposed shelf would also increase the atmospheric load to more remote places has not been investigated. Polar ice cores offer a unique opportunity to study the atmospheric transport of aerosols on various timescales, from glacial-interglacial periods to recent anthropogenic influences. We have for the first time determined the atmospheric transport of phosphorus to the Arctic by means of ice core analysis. Both total and dissolved reactive phosphorus were measured to investigate current and past atmospheric transport of phosphorus to the Arctic. Results show that glacial cold stadials had increased atmospheric total phosphorus mass loads of 70 times higher than in the past century, while DRP was only increased by a factor of 14. In the recent period we find evidence of a phosphorus increase over the past 50 yrs in ice cores close to human occupation likely correlated to forest fires. References: Kjær, Helle Astrid, et al. "Continuous flow analysis method for determination of dissolved reactive phosphorus in ice cores." Environmental science & technology 47.21 (2013): 12325-12332. Kjær, Helle Astrid, et al. "Greenland ice cores constrain glacial atmospheric fluxes of phosphorus." Journal of Geophysical Research: Atmospheres120.20 (2015).

  4. [Multivariate analysis of heavy metal element concentrations in atmospheric deposition in Harbin City, northeast China].

    Science.gov (United States)

    Tang, Jie; Han, Wei-Zheng; Li, Na; Li, Zhao-Yang; Bian, Jian-Min; Li, Hai-Yi

    2011-11-01

    In order to understand the characteristics of atmospheric heavy metal deposition in Harbin City, 46 deposition samples were collected which were taken using bulk deposition samplers during the period of 2008-2009 (about 365 days). The samples were analyzed for heavy metal concentration by atomic fluorescence spectrometry (AFS) and inductively coupled plasma-atomic spectrometry (ICP-AES). The deposition flux was calculated. Sources analysis was made by the method of principal component analysis (PCA), Pearsons and enrichment factor (EF). The following points can be gained through multivariate analysis. Mn and Co are mostly from natural sources while the others may be brought by coal dust, vehicle emissions and metal smelting.

  5. Atmospheric Deposition Modeling Results

    Data.gov (United States)

    U.S. Environmental Protection Agency — This asset provides data on model results for dry and total deposition of sulfur, nitrogen and base cation species. Components include deposition velocities, dry...

  6. Atmospheric organic nitrogen deposition: Analysis of nationwide data and a case study in Northeast China

    International Nuclear Information System (INIS)

    The origin of atmospheric dissolved organic nitrogen (DON) deposition is not very clear at present. Across China, the DON deposition was substantially larger than that of world and Europe, and we found significant positive correlation between contribution of DON and the deposition flux with pristine site data lying in outlier, possibly reflecting the acute air quality problems in China. For a case study in Northeast China, we revealed the deposited DON was mainly derived from intensive agricultural activities rather than the natural sources by analyzing the compiled dataset across China and correlating DON flux with NH4+–N and NO3−–N. Crop pollens and combustion of fossil fuels for heating probably contributed to summer and autumn DON flux respectively. Overall, in Northeast China, DON deposition could exert important roles in agro-ecosystem nutrient management and carbon sequestration of natural ecosystems; nationally, it was suggested to found rational network for monitoring DON deposition. -- Highlights: •Contribution and deposition flux of DON across China was positively correlated. •Deposited DON was more influenced by human in China than across the world and Europe. •DON of a farmland in Northeast China was mainly derived from agricultural activities. •Crop pollen and combustion of fossil fuels contributed to summer and autumn DON. •Deposited DON should not be neglected when evaluating its ecological impacts. -- Synthesis of DON deposition across China implied regional importance of anthropogenic sources, and an observation in Northeast China suggested the ecological significances of the DON flux should be considered

  7. Atmospheric deposition of heavy metals studied by analysis of moss samples using neutron activation analysis and atomic absorption spectrometry

    International Nuclear Information System (INIS)

    In a study of the atmospheric deposition of trace elements in different parts of Norway samples of the moss Hylocomium splendens were analyzed with respect to 26 elements. The determination of Cu, Zn, Pb, Cd and Ni was carried out by flame atomic absorption spectrometry, while an additional 21 elements were determined by instrumental neutron activation analysis. Several elements showed a substantially higher deposition in the southernmost parts of Norway than in places located farther north. As regards Pb, As and Sb, the difference amounted to a factor of ten or more. A similar but less pronounced trend was evident for elements such as V, Zn, Cd, Se and Ag. In some cases local pollution sources or marine aerosols had a significant effect on the results. For several heavy metals however long-distance transport from areas to the south and the south west of Norway was responsible for a major part of the air pollution

  8. Atmospheric deposition of heavy metals in Wuxi, China: estimation based on native moss analysis.

    Science.gov (United States)

    Yan, Yun; Zhang, Qiang; Wang, G Geoff; Fang, Yan-Ming

    2016-06-01

    We studied atmospheric deposition of heavy metals in Wuxi, China, using moss (Haplocladium microphyllum and H. angustifolium) as a biomonitoring agent. Moss samples were collected from 49 sites determined by a systematic sampling method. The top layer of soil on each site was also sampled. No significant correlation (P ArcGIS 9.0. A total pollution coefficient was calculated for each sampling site to identify the seriously polluted areas in the region.

  9. Temporal and spatial trends studied by lichen analysis: atmospheric deposition of trace elements in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Aspiazu, J.; Cervantes, L.; Ramirez, J.; Lopez, J.; Villasenor, P. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Ramos, R.; Munoz, R. [Secretaria del Medio Ambiente, Gestion Ambiental del Aire, Mexico City (Mexico)

    2007-07-01

    Ball moss on Tillandsia recurvata (Bromeliaceae), collected in an area previously identified as unpolluted, was transplanted to thirteen bio-monitoring sites in the downtown and metropolitan areas of Mexico City (which cover a surface of 9,560 km{sup 2}) during the periods August 2002 - January 2003 and July 2003 - October 2003. A total of 52 lichens (weighing 300 g) were transplanted to each place. Two were analysed as zero or reference, El Chico National Park, a location 100 Km upwind from the city and the remaining 26 were hung in nylon net bags in order to be able to collect two transplanted tree month, out of every season over a one-year period. The concentrations were measured by the quantitative PIXE method based on an extemal beam facility. The atmospheric deposition for trace elements was inferred by its concentration in lichen samples collected in 2002 from 13 sites in Mexico and compared with data from a similar survey in 2003. The concentration of Cr, Cu, Co, Fe, Mn, Ni, Pb and Zn and other elements was determined for each sample. Maps for each element were drawn after a geostatistical estimate of the metal concentration in the sample was made. Maps were drawn for all elements with the estimated values. Geographical distribution patterns were obtained for the different metals, reflecting the contribution of natural and anthropogenic emission sources. The deposition patterns of V, As, Se, Cd and Pb are substantially influenced by long-range transport from other parts of Mexico City. For Cr, Fe, Co, Ni, and Cu, the deposition patterns are largely determined by contribution from point sources within Mexico and in the metropolitan area. The lichen data for Br and, in part, Se reflect an airborne supply from the environment. Contributions to trace element concentrations in lichen sources other than atmospheric deposition are identified and discussed. The Spatial and temporal variations in the distribution of metal concentration are discussed. (Author)

  10. Atmospheric deposition studies of heavy metals in Arctic by comparative analysis of lichens and cryoconite.

    Science.gov (United States)

    Singh, Shiv Mohan; Sharma, Jagdev; Gawas-Sakhalkar, Puja; Upadhyay, Ajay K; Naik, Simantini; Pedneker, Shailesh M; Ravindra, Rasik

    2013-02-01

    Lichens and cryoconite (rounded or granular, brownish-black debris occurring in holes on the glacier surface) from Ny-Ålesund were used for understanding the elemental deposition pattern in the area. Lichen samples collected from low-lying coastal region and cryoconite samples from high altitudinal glacier area were processed and analysed for elements such as aluminium (Al), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), cesium (Cs), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), vanadium (V) and zinc (Zn) through inductively coupled plasma mass spectrometry. Results showed that heavy metals, Al and Fe, are present in high concentration in the cryoconite samples. Al was also present in high amounts in seven of the eight lichen samples studied. The general scheme of elements in the decreasing order of their concentrations for most of the cryoconite samples was Al > Fe > Mn > Zn > V > Pb > Cr > Ni > Cu > Co > As > Cs > Cd while that for the lichen samples was Al > Fe > Zn > Mn > Pb > Cu > Cs > Cr > Ni > V > Co > As > Cd. Similarity in trends in the two sample types confirms that the environment indeed contains these elements in that order of concentration which overtime got accumulated in the samples. Overall comparison showed most elements to be present in high concentrations in the cryoconite samples as compared to the lichen samples. Within the lichens, elemental accumulation data suggests that the low-lying site (L-2) from where Cladonia mediterranea sample was collected was the most polluted accumulating a number of elements at high concentrations. The probable reasons for such deposition patterns in the region could be natural (crustal contribution and sea salt spray) and anthropogenic (local and long-distance transmission of dust particles). In the future, this data can form a baseline for monitoring quantum of atmospheric heavy metal deposition in lichens and cryoconite of Svalbard, Arctic.

  11. Methods of trend analysis for atmospheric deposition into the sea; Trendabschaetzung atmosphaerischer Stoffeintraege in die Meere

    Energy Technology Data Exchange (ETDEWEB)

    Kuhbier, P.; Uhlig, S.; Fraenzel, A.; Schick, N.

    2001-02-01

    In order to prevent a considerable deterioration in the detectability of time trends in depositions as a result of fluctuations in the climatic conditions, an adjustment whereby the entry data are recomputed into an 'average' weather conditions appears inevitable. Accordingly, the aim of the project was the development of a concept for the adjustment and trend analysis of depositions including the examination of a number of statistical methods, with the form of the adjustment being the focus of the work. As per this concept, adjustment takes place on the basis of monthly data. The adjusted depositions are then summarized before trend analysis follows on the basis of these adjusted annual depositions. Finally the trend sensitivity of the method is examined as part of a power analysis. A data bank-based software was developed as part of the project in order to carry out the extensive calculations. With this software, the most diverse trend analysis and adjustment methods were realised and tested. It may first of all be noted that the evaluations conducted confirm the practicality of the adjustment concept developed, with various methods being deployable for fixing the adjustment parameter according to the measurement site and parameter concerned. The average reduction in the scatter of the annual depositions vis-'a-vis the non-adjusted depositions is over 40%. This amounts to a substantial improvement in trend sensitivity and makes for a clear reduction in the length of the requisite time series. However, there is no method among the adjustment methods investigated which, considering all the prerequisites, may be regarded as being superior to the other methods. The question as to which form of adjustment yields the most favourable results depends on the pollutants and the site-related conditions in each case. (orig.) [German] Um zu verhindern, dass durch klimatische Schwankungen die Nachweisbarkeit zeitlicher Trends in Depositionen wesentlich

  12. Monitoring the heavy metal atmospheric deposition in Romania using the neutron activation analysis of bio-indicators

    International Nuclear Information System (INIS)

    This research is the direct result of a protocol between NIPNE-HH Bucharest, Romania and JINR-Dubna, Russia on one side, and NIPNE-HH Bucharest, Romania and the University of Trondheim, Norway on the other side. Since the summer of 1995, a systematic sampling of bio-indicators has been carried out. The bio-indicators are represented by three species of bryophytes with an endemic development in the Romanian area: Hylocomium splendens, Hypnum cupresiforme and Pleurozium schreberi. A large area of 45,000 km2, including the Carpathian Arch between the Olt River Gorge (Southern Carpathian Mountains) and the northern Romanian border (Eastern Carpathian Mountains) was covered. Some of the samples were prepared in the laboratory and analyzed by nuclear analysis methods of a high sensitivity and accuracy i.e., neutron activation analysis and atomic absorption spectrometry. Other samples are to be prepared and analyzed. The results will be shown as distribution maps for heavy metal concentrations in the studied area. The analysis were carried out at NIPNE-HH-Bucharest, JINR-Dubna and Trondheim University. Part of the results have already been included in the European Atlas of the Heavy Metal Atmospheric Depositions, published by the Northern Countries Council. The distribution maps of atmospheric depositions in Romania will also be included in the above mentioned Atlas. (author)

  13. Atmospheric nitrogen deposition in the Rocky Mountains of Colorado and southern Wyoming - A review and new analysis of past study results

    Science.gov (United States)

    Burns, Douglas A.

    2003-01-01

    The Rocky Mountain region of Colorado and southern Wyoming receives as much as 7kgha-1yr-1 of atmospheric nitrogen (N) deposition, an amount that may have caused changes in aquatic and terrestrial life in otherwise pristine ecosystems. Results from published studies indicate a long-term increase in the rate of atmospheric N deposition during the 20th century, but data from the National Atmospheric Deposition Program and Clean Air Status and Trends Network show no region-wide increase during the past 2 decades. Nitrogen loads in atmospheric wet deposition have increased since the mid-1980s, however, at three high elevation (>3000m) sites east of the Continental Divide in the Front Range. Much of this increase is the result of increased ammonium (NH4+) concentrations in wet deposition. This suggests an increase in contributions from agricultural areas or from vehicles east of the Rocky Mountains and is consistent with the results of previous studies that have suggested a significant eastern source for atmospheric N deposition to the Front Range. The four sites with the highest NH4+ concentrations in wet deposition were among the six easternmost NADP sites, which is also consistent with a source to the east of the Rockies. This analysis found an increase in N loads in wet deposition at Niwot Ridge of only 0.013kgha-1yr-1, more than an order of magnitude less than previously reported for this site. This lower rate of increase results from application of the non-parametric Seasonal Kendall trend test to mean monthly data, which failed a test for normality, in contrast to linear regression, which was applied to mean annual data in a previous study. Current upward trends in population growth and energy use in Colorado and throughout the west suggest a need for continued monitoring of atmospheric deposition of N, and may reveal more widespread trends in N deposition in the future.

  14. UFOMOD - atmospheric dispersion and deposition

    International Nuclear Information System (INIS)

    The report gives an introduction into the modelling of atmospheric dispersion and deposition which has been implemented in the new program system UFOMOD for assessing the consequences after nuclear accidents. According to the new structure of UFOMOD, different trajectory models with ranges of validity near to the site and at far distances are applied. Emphasis is laid on the description of the segmented plume model MUSEMET and its affilated submodels, being the removal of activity from the cloud by dry and wet deposition, and special effects like plume rise and the behaviour of plumes released into building wakes. In addition, the evaluation of γ-dose correction factors to take account of the finite extent of the radioactive plume in the near range (up to about 20 km) are described. Only brief introductions are given into the principles of the other models available: the puff model RIMPUFF, the long-range puff model MESOS, and the special straight-line Gaussian model ISOLA which are used if low-level long-duration releases are considered. To define starting times of weather sequences and the probabilities of occurrence of these sequences, it is convenient to perform stratified sampling. Therefore, the preprocessing program package METSAM has been developed to perform for generic ACAs a random sampling of weather sequences out off a population of classified weather conditions. The sampling procedure and a detailed input/output (I/O) description is presented and an additional appendix, respectively. A general overview on the I/O structure of MUSEMET as well as a brief user guide to run the KfK version of the MESOS code are also given in the appendix. (orig.)

  15. MEAD Marine Effects of Atmospheric Deposition

    Science.gov (United States)

    Jickells, T.; Spokes, L.

    2003-04-01

    atmospheric deposition to be an important source of nitrogen and where various eutrophication problems are evident. Fieldwork has involved atmospheric and water column measurements using ships, automated buoys and coastal stations. The results obtained have then been used in computer models which allow us to determine how atmospheric pollutants are transported in the atmosphere, deposited to the ocean and how this affects the growth of algae. These models have then been used to predict whether changing the amounts and types of pollutants entering the atmosphere will affect algal growth in coastal waters. We have also used existing monitoring data on phytoplankton abundance in the Kattegat in a retrospective analysis to identify incidences of blooms and test for any relation between these and atmospheric deposition. The final product of the MEAD project has been an improved scientific understanding of the transport and deposition of nitrogen in coastal waters and the effect of such deposition on phytoplankton ecosystems. These results will, we hope, allow policy makers to make rational decisions as to whether increased regulation of atmospheric nitrogen emissions are necessary.

  16. DETERMINATION METHODS OF THE ATMOSPHERIC DEPOSITION

    Directory of Open Access Journals (Sweden)

    Hanefi BAYRAKTAR

    2004-01-01

    Full Text Available The atmospheric deposition is defined as the turning back of pollutants to the earth, emitted either from natural or anthropogenic sources, after the some transformation stages of pollutants in the atmosphere. Because the atmospheric deposition (wet and dry deposition damages water, plants, soil, historical and other structures, it is one of the popular subject to study in recent years. However, it is difficult to study the determination of atmospheric deposition because it has a lot of various and changeable parameters. So, there is a need for various systems and surfaces for sampling. As wet deposition can be sampled by manual and automatic systems, the different developed sampling surfaces which minimize the effect of various topographic and meteorological conditions are used to sample dry deposition. Studies show that sampling with water surfaces is more suitable to collect both dry and bulk deposition. In this study, atmospheric deposition and its determination methods were explained and sampling surfaces that were developed to collect deposition of different air pollutants compared each other.

  17. Atmospheric Deposition of Heavy Metals in Serbia Studied by Moss Biomonitoring, Neutron Activation Analysis and GIS Technology

    CERN Document Server

    Frontasyeva, M V; Kumar, M; Matavuly, M; Pavlov, S S; Radnovic, D; Steinnes, E

    2002-01-01

    The results of a pilot study on atmospheric deposition of heavy metals and other trace elements using the moss biomonitoring technique in the northern part of Serbia and some areas of Bosnia are presented. Samples of Hypnum cupressiforme along with some other moss types were collected at 92 sites during the summer of 2000. A total of 44 elements were determined by instrumental neutron activation analysis using epithermal neutrons. The observed levels of Cu, Zn, As, Ag, Cd, In, Sb, etc. in the area surrounding the town of Bor (Serbia) are comparable to those reported from similar industrial areas in other countries such as the Copper Basin in Poland and the South Urals of Russia. In the same region the maximum Se and Mo concentrations are the highest ever recorded in biomonitoring studies using mosses. High median concentrations of Fe and Ni in Serbian mosses are associated with a crustal component as apparent from factor analysis of the moss data. This component could be a result of windblown soil dust (most ...

  18. Analysis of polybrominated diphenyl ethers in atmospheric deposition and snow samples by solid-phase disk extraction.

    Science.gov (United States)

    Quiroz, Roberto; Arellano, Lourdes; Grimalt, Joan O; Fernández, Pilar

    2008-05-23

    An extraction method for the quantitative analysis of polybrominated diphenyl ethers (PBDEs) in aqueous samples has been evaluated. The analytical methodology includes the sample filtration through glass fiber filter and subsequent extraction of dissolved phase compounds by C18 solid-phase disk extraction. Dependence of extraction efficiency on factors such as pollutant concentrations, sample volume, and stability during storage has been investigated. Mean extraction efficiencies of 97% for total PBDEs (13 tri- to heptabrominated congeners at spiking levels in the range of 15-90pg) with a RSD between 9 and 20% were achieved. Higher recoveries were observed for the more volatile PBDEs (112%) in relation to more brominated congeners (88%). The developed methodology was successfully applied to the analysis of these compounds in atmospheric deposition and snow samples from remote sites in Europe with method detection and quantitation limits in the range of 2.1-10pgL(-1) for almost all congeners, which allow the determination of PBDEs in remote areas with levels in the range of low to medium pgL(-1) for SigmaPBDEs.

  19. Atmospheric deposition maps for the Rocky Mountains

    Science.gov (United States)

    Nanus, L.; Campbell, D.H.; Ingersoll, G.P.; Clow, D.W.; Mast, M.A.

    2003-01-01

    Variability in atmospheric deposition across the Rocky Mountains is influenced by elevation, slope, aspect, and precipitation amount and by regional and local sources of air pollution. To improve estimates of deposition in mountainous regions, maps of average annual atmospheric deposition loadings of nitrate, sulfate, and acidity were developed for the Rocky Mountains by using spatial statistics. A parameter-elevation regressions on independent slopes model (PRISM) was incorporated to account for variations in precipitation amount over mountainous regions. Chemical data were obtained from the National Atmospheric Deposition Program/National Trends Network and from annual snowpack surveys conducted by the US Geological Survey and National Park Service, in cooperation with other Federal, State and local agencies. Surface concentration maps were created by ordinary kriging in a geographic information system, using a local trend and mathematical model to estimate the spatial variance. Atmospheric-deposition maps were constructed at 1-km resolution by multiplying surface concentrations from the kriged grid and estimates of precipitation amount from the PRISM model. Maps indicate an increasing spatial trend in concentration and deposition of the modeled constituents, particularly nitrate and sulfate, from north to south throughout the Rocky Mountains and identify hot-spots of atmospheric deposition that result from combined local and regional sources of air pollution. Highest nitrate (2.5-3.0kg/ha N) and sulfate (10.0-12.0kg/ha SO4) deposition is found in northern Colorado.

  20. Atmospheric deposition of heavy metals in Norway studied by the analysis of moss samples using neutron activation analysis and atomic absorption spectrometry

    International Nuclear Information System (INIS)

    In a study of the atmospheric deposition of trace elements in different parts of Norway, samples of the moss Hylocomium Splendens were analyzed with respect to 28 elements. The determination of Cu, Zn, Cd and Pb was carried out by atomic absorption spectrophotometry, while 24 additional elements were determined by instrumental neutron activation analysis. In samples from southemmost Norway, a substantially higher concentration was found for elements such as Pb, Sb, V, Cr, Cu, Zn, As, Se, Mo, Ag and Cd than in samples from places located in the more northerly parts of the country. The results indicate that sources which are to the south and south-west of Scandinavia, contribute significantly to heavy metal deposition in Norway. (author)

  1. The Correlation Between Atmospheric Dust Deposition to the Surface Ocean and SeaWiFS Ocean Color: A Global Satellite-Based Analysis

    Science.gov (United States)

    Erickson, D. J., III; Hernandez, J.; Ginoux, P.; Gregg, W.; Kawa, R.; Behrenfeld, M.; Esaias, W.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Since the atmospheric deposition of iron has been linked to primary productivity in various oceanic regions, we have conducted an objective study of the correlation of dust deposition and satellite remotely sensed surface ocean chlorophyll concentrations. We present a global analysis of the correlation between atmospheric dust deposition derived from a satellite-based 3-D atmospheric transport model and SeaWiFs estimates of ocean color. We use the monthly mean dust deposition fields of Ginoux et al. which are based on a global model of dust generation and transport. This model is driven by atmospheric circulation from the Data Assimilation Office (DAO) for the period 1995-1998. This global dust model is constrained by several satellite estimates of standard circulation characteristics. We then perform an analysis of the correlation between the dust deposition and the 1998 SeaWIFS ocean color data for each 2.0 deg x 2.5 deg lat/long grid point, for each month of the year. The results are surprisingly robust. The region between 40 S and 60 S has correlation coefficients from 0.6 to 0.95, statistically significant at the 0.05 level. There are swaths of high correlation at the edges of some major ocean current systems. We interpret these correlations as reflecting areas that have shear related turbulence bringing nitrogen and phosphorus from depth into the surface ocean, and the atmospheric supply of iron provides the limiting nutrient and the correlation between iron deposition and surface ocean chlorophyll is high. There is a region in the western North Pacific with high correlation, reflecting the input of Asian dust to that region. The southern hemisphere has an average correlation coefficient of 0.72 compared that in the northern hemisphere of 0.42 consistent with present conceptual models of where atmospheric iron deposition may play a role in surface ocean biogeochemical cycles. The spatial structure of the correlation fields will be discussed within the context

  2. Washout and dry deposition of atmospheric aerosols

    International Nuclear Information System (INIS)

    The deposition velocities onto different rough surfaces and the washout coefficients of simulated rain droplets for submicron aerosols were studied in a wind channel. The influence of particle size and electric charge upon the collection efficiencies of simulated rain droplets was measured. The deposition velocity of the particles was determined as a function of aerosol size, wind velocity and roughness of the surface. The experiments were carried out with monodisperse, radioactive particles with sizes which were varied from 0.03 and 5 μm. Using the measured values, the activity flux of the long lived radon decay product (RaD), the mass flux of the atmospheric aerosol and the activity flux near a stack of a nuclear power plant onto the ground surface were calculated considering washout, rainout and dry deposition in the atmosphere. (author)

  3. Atmospheric Deposition of Copper and Zinc in Maramures County (Romania)

    OpenAIRE

    Buteana Claudia; Berinde Zoita M.; Mihali Cristina; Michnea Angela M.; Gavra Anamaria; Simionescu Mirela

    2014-01-01

    The need to reduce pollution to levels that minimize adverse effects on human health involve the monitoring of air quality, including dry depositions and their metal content. The analysis of these parameters aims to investigate the air quality in Maramures County (with nonferrous mining activities) and in the Romanian - Ukraine transboundary area. The paper presents the experimental results obtained for dry atmospheric deposition of copper and zinc using flame atomic absorption spectrometry (...

  4. Atmospheric deposition fluxes to Monetary Bay

    Science.gov (United States)

    Gray, E.; Paytan, A.; Ryan, J.

    2008-12-01

    Atmospheric deposition has been widely recognized as a source of pollutants and nutrients to coastal ecosystems. Specifically, deposition includes nitrogen compounds, sulfur compounds, mercury, pesticides, phosphate, trace metals and other toxic compounds that can travel great distances. Sources of these components include both natural (volcanoes, mineral dust, forest fires) and anthropogenic (fossil fuels, chemical byproducts, incineration of waste) sources, which may contribute to harmful health and environmental impacts such as eutrophication, contaminated fish and harmful algal blooms. This study looks at the flux of aerosol deposition (TSP - total suspended particle load) to Monterey Bay, California. Samples are collected on a cascade impactor aerosol sampler (size fractions PM 2.5 and PM 10) every 48 hours continuously. Preliminary results indicate that the TSP for PM 10 ranged from 0.026 to 0.104 mg m-3 of air and for PM 2.5 from 0.014 to 0.046 mg m-3 of air. Using a deposition velocity of 2 cm s-1 for the large fraction (PM10 - PM 2.5) and a deposition velocity of 0.7 cm s-1 for the fine fraction (PM 2.5) deposition rates are 13 and 86 mg m-2 d-1 respectively.

  5. Alkylphenols in atmospheric depositions and urban runoff.

    Science.gov (United States)

    Bressy, A; Gromaire, M-C; Lorgeoux, C; Chebbo, G

    2011-01-01

    A sampling campaign was conducted in order to determine alkylphenol (AP) concentrations in stormwater as well as potential AP sources in suburban environments. An analytical procedure was developed to quantify APs in bulk atmospheric deposition, building runoff, road runoff and stormwater. Both nonylphenols and octylphenols could be quantified in each sample. Median stormwater concentrations amounted to: 470 ng/l for nonylphenols, and 36 ng/l for octylphenols. These concentrations are 3 times higher than those found in atmospheric deposition, thus proving that local human activity constitutes a significant source of contamination. The contributions of the various sources to stormwater have been assessed from mass balances at the catchment scale. 70% of AP mass in stormwater originates from building and road emissions. Annual AP fluxes have been extrapolated from the total AP mass measured over our sampling periods for atmospheric depositions (44 to 84 µgNP/m(2)/yr) and stormwater (100 to 190 µgNP/m(2)/yr). Moreover, since APs were mainly found in the dissolved fraction, runoff treatment devices based on settling are unlikely to be very efficient. PMID:21330713

  6. Dispersion, deposition and resuspension of atmospheric contaminants

    International Nuclear Information System (INIS)

    The following topics are discussed: dry deposition, oil shale fugitive air emissions, particle resuspension and translocation, theoretical studies and applications, and processing of emissions by clouds and precipitation. The concentration of contaminant species in air is governed by the rate of input from sources, the rate of dilution or dispersion as a result of air turbulence, and the rate of removal to the surface by wet and dry deposition processes. Once on the surface, contaminants also may be resuspended, depending on meteorological and surface conditions. An understanding of these processes is necessary for accurate prediction of exposures of hazardous or harmful contaminants to humans, animals, and crops. In the field, plume dispersion and plume depletion by dry deposition were studied by the use of tracers. Dry deposition was investigated for particles of both respiration and inhalation interest. Complementary dry deposition studies of particles to rock canopies were conducted under controlled conditions in a wind tunnel. Because of increasing concern about hazardous, organic gases in the atmosphere some limited investigations of the dry deposition of nitrobenzene to a lichen mat were conducted in a stirred chamber. Resuspension was also studied using tracers and contaminated surfaces and in the wind tunnel. The objective of the resuspension studies was to develop and verify models for predicting the airborne concentrations of contaminants over areas with surface contamination, develop resuspension rate predictors for downwind transport, and develop predictors for resuspension input to the food chain. These models will be of particular relevance to the evaluation of deposition and resuspension of both radionuclides and chemical contaminants

  7. Assessment of Atmospheric heavy metal deposition in North Egypt aerosols using neutron activation analysis and optical emission inductively coupled plasma

    International Nuclear Information System (INIS)

    The aim of the present study is to assess the current level of atmospheric heavy metal pollution of aerosols in different cities of North Egypt using the neutron activation analysis and optical emission inductively coupled plasma techniques. The results revealed that the highest concentrations of particulate matter PM10 and total suspended particulate matter were close to industrial areas. From the results of the enrichment factor calculations, the most significant elements of anthropogenic origin are Ba, Sb, Ce and Zn. - Highlights: → Average concentration of Cd using OE-ICP is below detection limit for all the samples. → Maximum average concentration of Pb in PM10 and TSP is 5425 and 570.3, respectively. → Concentration of 20 elements in PM10 and TSP aerosols are determined using the NAA. → EF revealed that Pb, Ba, Br, Ce, Hf, La Sb and Zn are of anthropogenic origin.

  8. Assessment of Atmospheric heavy metal deposition in North Egypt aerosols using neutron activation analysis and optical emission inductively coupled plasma

    Energy Technology Data Exchange (ETDEWEB)

    El-Araby, E.H., E-mail: elaraby_20032000@yahoo.com [Faculty of Science, Physics Department, Jezan University, KSA (Saudi Arabia); Abd El-Wahab, M., E-mail: wahab_magda@yahoo.com [Faculty of women for Arts, Science and Education, Physics Department, Ain Shams University, PO11757 Cairo (Egypt); Diab, H.M., E-mail: hnndiab@yahoo.co.uk [National Center of Nuclear Safety and Radiation Control, Atomic Energy Authority Cairo (Egypt); El-Desouky, T.M., E-mail: trkhegazy@yahoo.com [Faculty of women for Arts, Science and Education, Physics Department, Ain Shams University, PO11757 Cairo (Egypt); Mohsen, M., E-mail: m1mohsen@yahoo.com [Faculty of Science. Physics Department, Ain-Shams University, PO 11566 Cairo (Egypt)

    2011-10-15

    The aim of the present study is to assess the current level of atmospheric heavy metal pollution of aerosols in different cities of North Egypt using the neutron activation analysis and optical emission inductively coupled plasma techniques. The results revealed that the highest concentrations of particulate matter PM{sub 10} and total suspended particulate matter were close to industrial areas. From the results of the enrichment factor calculations, the most significant elements of anthropogenic origin are Ba, Sb, Ce and Zn. - Highlights: > Average concentration of Cd using OE-ICP is below detection limit for all the samples. > Maximum average concentration of Pb in PM10 and TSP is 5425 and 570.3, respectively. > Concentration of 20 elements in PM{sub 10} and TSP aerosols are determined using the NAA. > EF revealed that Pb, Ba, Br, Ce, Hf, La Sb and Zn are of anthropogenic origin.

  9. Ecological effects of atmospheric nitrogen deposition on soil enzyme activity

    Institute of Scientific and Technical Information of China (English)

    WANG Cong-yan; Lv Yan-na; LIU Xue-yan Liu; WANG Lei

    2013-01-01

    The continuing increase in human activities is causing global changes such as increased deposition of atmospheric nitrogen.There is considerable interest in understanding the effects of increasing atmospheric nitrogen deposition on soil enzyme activities,specifically in terms of global nitrogen cycling and its potential future contribution to global climate change.This paper summarizes the ecological effects of atmospheric nitrogen deposition on soil enzyme activities,including size-effects,stage-effects,site-effects,and the effects of different levels and forms of atmospheric nitrogen deposition.We discuss needs for further research on the relationship between atmospheric nitrogen deposition and soil enzymes.

  10. Atmospheric deposition of rare earth elements in Albania studied by the moss biomonitoring technique, neutron activation analysis and GIS technology.

    Science.gov (United States)

    Allajbeu, Sh; Yushin, N S; Qarri, F; Duliu, O G; Lazo, P; Frontasyeva, M V

    2016-07-01

    Rare earth elements (REEs) are typically conservative elements that are scarcely derived from anthropogenic sources. The mobilization of REEs in the environment requires the monitoring of these elements in environmental matrices, in which they are present at trace level. The determination of 11 REEs in carpet-forming moss species (Hypnum cupressiforme) collected from 44 sampling sites over the whole territory of the country were done by using epithermal neutron activation analysis (ENAA) at IBR-2 fast pulsed reactor in Dubna. This paper is focused on REEs (lanthanides) and Sc. Fe as typical consistent element and Th that appeared good correlations between the elements of lanthanides are included in this paper. Th, Sc, and REEs were never previously determined in the air deposition of Albania. Descriptive statistics were used for data treatment using MINITAB 17 software package. The median values of the elements under investigation were compared with those of the neighboring countries such as Bulgaria, Macedonia, Romania, and Serbia, as well as Norway which is selected as a clean area. Geographical distribution maps of the elements over the sampled territory were constructed using geographic information system (GIS) technology. Geochemical behavior of REEs in moss samples has been studied by using the ternary diagram of Sc-La-Th, Spider diagrams and multivariate analysis. It was revealed that the accumulation of REEs in current mosses is associated with the wind-blowing metal-enriched soils that is pointed out as the main emitting factor of the elements under investigation. PMID:27044293

  11. Atmospheric deposition of rare earth elements in Albania studied by the moss biomonitoring technique, neutron activation analysis and GIS technology.

    Science.gov (United States)

    Allajbeu, Sh; Yushin, N S; Qarri, F; Duliu, O G; Lazo, P; Frontasyeva, M V

    2016-07-01

    Rare earth elements (REEs) are typically conservative elements that are scarcely derived from anthropogenic sources. The mobilization of REEs in the environment requires the monitoring of these elements in environmental matrices, in which they are present at trace level. The determination of 11 REEs in carpet-forming moss species (Hypnum cupressiforme) collected from 44 sampling sites over the whole territory of the country were done by using epithermal neutron activation analysis (ENAA) at IBR-2 fast pulsed reactor in Dubna. This paper is focused on REEs (lanthanides) and Sc. Fe as typical consistent element and Th that appeared good correlations between the elements of lanthanides are included in this paper. Th, Sc, and REEs were never previously determined in the air deposition of Albania. Descriptive statistics were used for data treatment using MINITAB 17 software package. The median values of the elements under investigation were compared with those of the neighboring countries such as Bulgaria, Macedonia, Romania, and Serbia, as well as Norway which is selected as a clean area. Geographical distribution maps of the elements over the sampled territory were constructed using geographic information system (GIS) technology. Geochemical behavior of REEs in moss samples has been studied by using the ternary diagram of Sc-La-Th, Spider diagrams and multivariate analysis. It was revealed that the accumulation of REEs in current mosses is associated with the wind-blowing metal-enriched soils that is pointed out as the main emitting factor of the elements under investigation.

  12. Trends in the chemistry of atmospheric deposition and surface waters in the Lake Maggiore catchment

    Directory of Open Access Journals (Sweden)

    M. Rogora

    2001-01-01

    Full Text Available The Lake Maggiore catchment is the area of Italy most affected by acid deposition. Trend analysis was performed on long-term (15-30 years series of chemical analyses of atmospheric deposition, four small rivers draining forested catchments and four high mountain lakes. An improvement in the quality of atmospheric deposition was detected, due to decreasing sulphate concentration and increasing pH. Similar trends were also found in high mountain lakes and in small rivers. Atmospheric deposition, however, is still providing a large and steady flux of nitrogen compounds (nitrate and ammonium which is causing increasing nitrogen saturation in forest ecosystems and increasing nitrate levels in rivers. Besides atmospheric deposition, an important factor controlling water acidification and recovery is the weathering of rocks and soils which may be influenced by climate warming. A further factor is the episodic deposition of Saharan calcareous dust which contributes significantly to base cation deposition. Keywords: trend, atmospheric deposition, nitrogen, stream water chemistry.

  13. Atmospheric mass deposition by captured planetesimals

    Science.gov (United States)

    Iaroslavitz, Eyal; Podolak, Morris

    2007-04-01

    We examine the deposition of heavy elements in the envelope of a protoplanet growing according to the core accretion scenario of Pollack et al. [Pollack, J.B., Hubickyj, O., Bodenheimer, P., Lissauer, J.J., Podolak, M., Greenzweig, Y., 1996. Icarus 124, 62-85]. We use their atmospheric models and the deposition rates that they computed, and we calculate the amount of heavy elements that can be dissolved in the envelope. For planetesimals composed of a mixture of water, CHON, and rock, we find that almost all of the water is dissolved in the atmosphere. A substantial amount of CHON is also dissolved but it remains sequestered at high temperatures near the core. Some fraction of the rock is also dissolved in the very high temperature region near the core envelope boundary. If this dissolved material can be mixed upward later in the planet's evolution, the resulting structure would be much closer to that determined by matching the moments of Jupiter's gravitational field.

  14. Atmospheric heavy metal deposition in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Ruehling, Aa. (ed.)

    1994-03-01

    Atmospheric heavy metal deposition in Europe including 21 countries was monitored by the moss technique. The objectives of the project were to characterise qualitatively and quantitatively the regional atmospheric deposition pattern of heavy metals in background areas in Europe, to indicat the location of important heavy metal pollution sources. Samples of mainly the moss species Pleurozium schreberi, Hylocomium splendens and Hypnum cupresiforme were collected during the summertime 1990. The total concentrations of arsenic, cadmium, chromium, copper, iron, lead, nickel, vanadium and zinc were determined and the results presented in the form of coloured contour maps of Europe. In the Nordic countries and adjacent areas the regional deposition pattern of all the metals shows a decreasing gradient from relatively high values in the southern parts of Scandinavia to low values towards the North. A significant decreas. in the concentrations of most elements was found in this area during the last 10-20 years. Important local enhancements of the concentrations in moss were found superimposed on the regional background pattern, especially at the great smelting combinates in Nikel, Zapolyarnyj and Monchegorsk in Russia in the western part of the Kola Peninsula. Higher levels of metals are found at Mazeikiai (oil refinery) in Lithuania, close to Liepaja (steel mill) and Riga in Latvia and in the industrial north-eastern area of Estonia and adjacent area of Russia. Higher levels of metals were found in the metropolitan area of St. Petersburg. In Central Europe, Poland, and the Czech Republic have numerous sources of air pollution, as well as area in Germany. The Netherlands is particularly affected by pollution from Belgium and western Germany. The Environmental Monitoring and Data Group in the Nordic Countries would like the next survey of heavy metals, including mercury, in moss to take place in 1995. (EG) (45 refs.)

  15. Trends in the chemistry of atmospheric deposition and surface waters in the Lake Maggiore catchment

    OpenAIRE

    M. Rogora; Marchetto, A.; Mosello, R

    2001-01-01

    The Lake Maggiore catchment is the area of Italy most affected by acid deposition. Trend analysis was performed on long-term (15-30 years) series of chemical analyses of atmospheric deposition, four small rivers draining forested catchments and four high mountain lakes. An improvement in the quality of atmospheric deposition was detected, due to decreasing sulphate concentration and increasing pH. Similar trends were also found in high mountain lakes and in small rivers. Atmospheric depositio...

  16. A record of atmospheric Pb-210 deposition in The Netherlands

    NARCIS (Netherlands)

    Beks, J.P.; Eisma, D.; Van Der Plicht, J.

    1998-01-01

    The deposition flux of total atmospheric 210Pb has been measured at two sites in The Netherlands: Texel from 1992 to 1996 and Groningen from 1989 to 1994. With predominant westerly oceanic winds, the annual 210Pb deposition is relatively low as 222Rn, the source for atmospheric 210Pb, is mainly exha

  17. Trends in the chemistry of atmospheric deposition and surface waters in the Lake Maggiore catchment

    OpenAIRE

    M. Rogora; Marchetto, A.; Mosello, R

    2001-01-01

    International audience; The Lake Maggiore catchment is the area of Italy most affected by acid deposition. Trend analysis was performed on long-term (15-30 years) series of chemical analyses of atmospheric deposition, four small rivers draining forested catchments and four high mountain lakes. An improvement in the quality of atmospheric deposition was detected, due to decreasing sulphate concentration and increasing pH. Similar trends were also found in high mountain lakes and in small river...

  18. Trace metal determination in total atmospheric deposition in rural and urban areas

    OpenAIRE

    Azimi, Sam; Ludwig, Alexandre; Thevenot, Daniel,; Colin, Jean-Louis

    2003-01-01

    International audience The wet, dry and total atmospheric depositions of some metals (Al, Cd, Cr, Cu, Fe, Na, Pb and Zn) were sampled at two sites and atmospheric fallout fluxes were determined for these locations. This work, led by two different research groups, allowed to reach two main goals: to define a simple analytical procedure to secure accurate shipboard sampling and analysis of atmospheric deposition, and to assess anthropogenic impacts of heavy metals to the environment. The fir...

  19. Atmospheric iron deposition: global distribution, variability, and human perturbations

    OpenAIRE

    N. Mahowald; S. Engelstaedter; Luo, C; Sealy, A.; Artaxo, P.; Benitez-Nelson, C.R.; Bonnet, S.; Chen, Y.; Chuang, P. Y.; Cohen, D.; Dulac, F.; B. Herut; Johansen, A.M.; N. Kubilay; Losno, R.

    2009-01-01

    Atmospheric inputs of iron to the open ocean are hypothesized to modulate ocean biogeochemistry. This review presents an integration of available observations of atmospheric iron and iron deposition, and also covers bioavailable iron distributions. Methods for estimating temporal variability in ocean deposition over the recent past are reviewed. Desert dust iron is estimated to represent 95% of the global atmospheric iron cycle, and combustion sources of iron are responsible for the remaining...

  20. Assessment of atmospheric deposition of heavy metals and other elements in Belgrade using the moss biomonitoring technique and neutron activation analysis

    International Nuclear Information System (INIS)

    The study aimed at assessing atmospheric deposition of heavy metals and other elements using the moss genera Brachythecium sp. (B. rutabulum and B. salebrosum) and Eurhynchium sp. (E. hians and E. striatum) collected in autumn 2004 in the urban area of Belgrade. The concentrations of 36 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Mo, Sb, I, Cs, Ba, La, Ce, Sm, Tb, Dy, Hf, Ta, W, Hg, Th, U) were determined in moss and local topsoil samples by instrumental neutron activation analysis. The concentration of elements in moss positively correlated to those obtained for topsoil. High enrichment factors for As, Zn, Mo, Br, Sb, Se, Hg, and Cl, calculated to continental crust composition, gave an evidence for anthropogenic impact on urban area, mainly due to intensive vehicular traffic and fossil fuel combustion. The concentrations of elements in moss, characteristic for fossil fuel combustion, obtained in this study, were substantially lower than in the previous investigation (2000) conducted in the area of Belgrade. The level of concentrations for V, Cr, Ni, and As in moss from this study correlated to those measured for neighboring countries, and were several times higher than the base-level data from low polluted areas. The level of accumulated elements in both investigated moss genera were similar and all studied species could be combined for biomonitoring purposes in urban areas

  1. Atmospheric Deposition of Copper and Zinc in Maramures County (Romania

    Directory of Open Access Journals (Sweden)

    Buteana Claudia

    2014-12-01

    Full Text Available The need to reduce pollution to levels that minimize adverse effects on human health involve the monitoring of air quality, including dry depositions and their metal content. The analysis of these parameters aims to investigate the air quality in Maramures County (with nonferrous mining activities and in the Romanian - Ukraine transboundary area. The paper presents the experimental results obtained for dry atmospheric deposition of copper and zinc using flame atomic absorption spectrometry (FAAS. The samples were collected from four location/cities of Maramures County (Baia Mare, Sighetu Marmatiei, Viseu de Sus and Borsa during May-October 2014. The highest average values of copper concentration in the dry depositions were found in Baia Mare (199.88 μg/g, that is the most important industrial centre in Maramures County, followed by Borsa (111.49 μg/g, that used to be a nonferrous mining centre. In Viseu de Sus and Sighetu Marmatiei the average concentrations of copper in the dry depositions were lower: 75.63 μg/g and 64.26 μg/g, respectively. Zn average concentrations in dry depositions were 6.4-12 times higher than Cu concentrations. In Viseu de Sus and Borsa relative high values of Pearson correlation coefficients between the logarithm of Cu and Zn content in the dry deposition were found (0.702 and 0.737, respectively estimating that both pollutants in the ambient air have the same sources, probably the re-suspension of the dust from the tailing ponds. This study is implemented within the frame of ENPI Cross-border Cooperation Programme Hungary-Slovakia-Romania-Ukraine 2007-2013, in the project Clean Air Management in the Romania-Ukraine Transboundary Area - (CLAMROUA, financed by the European Union

  2. THE WATERSHED DEPOSITION TOOL: A MEANS TO LINK ATMOSPHERIC DEPOSITION TO WATERSHEDS

    Science.gov (United States)

    The potential for atmospheric deposition reductions to contribute to water quality management is not being included in many planning exercises. This is because often the water quality scientists do not know where to get and how to use projections of atmospheric deposition reducti...

  3. Multi-elements atmospheric deposition study in Albania.

    Science.gov (United States)

    Qarri, Flora; Lazo, Pranvera; Stafilov, Trajce; Frontasyeva, Marina; Harmens, Harry; Bekteshi, Lirim; Baceva, Katerina; Goryainova, Zoya

    2014-02-01

    For the first time, the moss biomonitoring technique and inductively coupled plasma-atomic emission spectrometric (ICP-AES) analytical technique were applied to study multi-element atmospheric deposition in Albania. Moss samples (Hypnum cupressiforme) were collected during the summer of 2011 and September-October 2010 from 62 sites, evenly distributed over the country. Sampling was performed in accordance with the LRTAP Convention-ICP Vegetation protocol and sampling strategy of the European Programme on Biomonitoring of Heavy Metal Atmospheric Deposition. ICP-AES analysis made it possible to determine concentrations of 19 elements including key toxic metals such as Pb, Cd, As, and Cu. Cluster and factor analysis with varimax rotation was applied to distinguish elements mainly of anthropogenic origin from those predominantly originating from natural sources. Geographical distribution maps of the elements over the sampled territory were constructed using GIS technology. The median values of the elements in moss samples of Albania were high for Al, Cr, Ni, Fe, and V and low for Cd, Cu, and Zn compared to other European countries, but generally were of a similar level as some of the neighboring countries such as Bulgaria, Croatia, Kosovo, Macedonia, and Romania. This study was conducted in the framework of ICP Vegetation in order to provide a reliable assessment of air quality throughout Albania and to produce information needed for better identification of contamination sources and improving the potential for assessing environmental and health risks in Albania, associated with toxic metals. PMID:24081920

  4. Atmospheric nitrogen compounds: Occurrence, composition and deposition

    DEFF Research Database (Denmark)

    Nielsen, T.; Pilegaard, K.; Egeløv, A.H.;

    1996-01-01

    Traffic in cities and on highways is an important contributor to NOy atmospheric pollution in open areas. In this situation both the concentration and composition of NOy compounds show a wide variation and are dependent on meteorological and atmospheric chemical conditions. The proportion of NOz....... The possibility that a significant contribution is caused by a group of unidentified NOy compounds cannot be excluded. Therefore, future investigations of atmospheric pollution of sensitive ecosystems, at conditions with a relatively high atmospheric content of NOy compared to that of NH3, ought to take...... into consideration the possible contribution from unidentified NOy compounds. This also implies that atmospheric research into the identity, occurrence, sources and sinks of these compounds-as well as further developments of sampling and analytical methods-should be given a high priority....

  5. Polycyclic aromatic hydrocarbons in atmospheric depositions around the Venice Lagoon

    OpenAIRE

    Rossini, Paolo; Matteucci, Gabriele; Raccanelli, Stefano; Favotto, Maurizio; Guerzoni, Stefano; Gattolin, Massimo

    2007-01-01

    Studies have revealed the potential risks to which human health and ecosystems are exposed in the Venice Lagoon, due to the atmospheric deposition of persistent pollutants such as trace metals and organic compounds. A total of 77 atmospheric bulk deposition samples were collected monthly from April 2002 to December 2004, from three sites located in the cities of Mestre and Venice, and inside the industrial area of Porto Marghera. Samples were analyzed by HRGC/HRMS for polycyclic aromatic hydr...

  6. Atmospheric Deposition of Phosphorus to the Everglades: Concepts, Constraints, and Published Deposition Rates for Ecosystem Management

    OpenAIRE

    Redfield, Garth W.

    2002-01-01

    This paper summarizes concepts underlying the atmospheric input of phosphorus (P) to ecosystems, published rates of P deposition, measurement methods, and approaches to future monitoring and research. P conveyed through the atmosphere can be a significant nutrient source for some freshwater and marine ecosystems. Particle sources and sinks at the land-air interface produce variation in P deposition from the atmosphere across temporal and spatial scales. Natural plant canopies can affect depos...

  7. Plasma deposition of thiophene derivatives under atmospheric pressure

    OpenAIRE

    DAMS, Roel; VANGENEUGDEN, Dirk; Vanderzande, Dirk

    2006-01-01

    Plasma deposition of conjugated polymer films under atmospheric pressure is described. Three thiophene derivatives (thiophene, 3-methylthiophene, and 3,4-ethylenedioxythiophene) are used as monomers. The plasma depositions with the various precursors are compared using analytical techniques such as X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, UV-vis spectroscopy, and resistance measurements. Good results are obtained with pulsed plasma depositions of...

  8. Operational mapping of atmospheric nitrogen deposition to the Baltic Sea

    OpenAIRE

    Hertel, O.; Ambelas Skjøth, C.; Brandt, J.; J.H. Christensen; Frohn, L. M.; J. Frydendall

    2003-01-01

    A new model system for mapping and forecasting nitrogen deposition to the Baltic Sea has been developed. The system is based on the Lagrangian variable scale transport-chemistry model ACDEP (Atmospheric Chemistry and Deposition model), and aims at delivering deposition estimates to be used as input to marine ecosystem models. The system is tested by comparison of model results to measurements from monitoring stations around the Baltic Sea. The comp...

  9. Energetic particle energy deposition in Titan's upper atmosphere

    Science.gov (United States)

    Westlake, J. H.; Smith, H. T.; Mitchell, D. G.; Paranicas, C. P.; Rymer, A. M.; Bell, J. M.; Waite, J. H., Jr.; Mandt, K. E.

    2012-04-01

    Titan’s upper atmosphere has been observed to be variable on a pass-by-pass basis. During the nominal mission where the Cassini Ion and Neutral Mass Spectrometer (INMS) only sampled the northern hemisphere this variability was initially believed to be tied to solar drivers manifest in latitudinal variations in the thermal structure of the upper atmosphere. However, when Cassini delved into the southern hemisphere the latitudinal dependence was not present in the data. Recently, Westlake et al. (2011) showed that the pass-by-pass variability is correlated with the deviations in the plasma environment as identified by Rymer et al. (2009) and Simon et al. (2010). Furthermore, the studies of Westlake et al. (2011) and Bell et al. (2011) showed that Titan’s upper atmosphere responds to changes in the ambient magnetospheric plasma on timescales of roughly one Titan day (16 Earth days). We report on recent studies of energy deposition in Titan’s upper atmosphere. Previous studies by Smith et al. (2009), Cravens et al. (2008), Tseng et al. (2008), and Shah et al. (2009) reported on energetic proton and oxygen ion precipitation. Back of the envelope calculations by Sittler et al. (2009) showed that magnetospheric energy inputs are expected to be of the order of or greater than the solar processes. We report on further analysis of the plasma environment around Titan during the flybys that the INMS has good data. We utilize data from the Magnetospheric Imaging Instrument to determine how the magnetospheric particle population varies from pass to pass and how this influences the net magnetospheric energy input prior to the flyby. We also report on enhanced energetic neutral atom emissions during select highly energetic passes. References: Bell, J., et al.: “Simulating the time-dependent response of Titan's upper atmosphere to periods of magnetospheric forcing”. Geophys. Res. Lett., Vol. 38, L06202, 2011. Rymer, A. M., et al.: “Discrete classification and electron

  10. Atmospheric Sulfur Deposition on Farmland in East China

    Institute of Scientific and Technical Information of China (English)

    WANG Ti-Jian; YANG Hao-Ming; GAO Li-Jie; ZHANG Yan; HU Zheng-Yi; XU Cheng-Kai

    2005-01-01

    Atmospheric sulfur deposition onto typical farmland in East China was investigated using both field measurements and numerical modeling. The field measurements were conducted at the Experiment Station of Red Soil Ecology, Chinese Academy of Sciences, 10 km from Yingtan, Jiangxi Province, East China, between November 1998 and October 1999, and at the Changshu Ecological Experiment Station, Chinese Academy of Sciences, in a rapidly developing region of Jiangsu Province, East China, between April 2001 and March 2002. The regional acid deposition model system (RegADMS), in which the dry deposition velocities of SO2 and sulfate aerosols (SO42-) were estimated using a big-leaf resistance analogy model, was applied to simulate air sulfur deposition over East China and sulfur deposition onto lands of different use types in East China. The wet scavenging coefficients were parameterized in terms of precipitation rate, and the effect of sub-grid processes due to inhomogeneous land use on dry deposition velocity was also included. Results of the field measurements showed that over 83% of the total sulfur deposition at the Yingtan site was dry deposition, while at the Changshu site42% was dry deposition. The total sulfur deposition was much larger at the Yingtan site than at the Changshu site, which suggested contrasting air pollution and meteorological situations. The modeling results revealed that the total annual sulfur deposition over East China was 1.88 Mt, of which 72.8% was deposited onto farmland, and dry deposition accounted for 43% of the total sulfur deposited. The modeling results were generally in agreement with those from the observations.Overall, this study suggested that atmospheric sulfur deposition played an important role in the soil sulfur balance, which could have a significant effect on agricultural ecosystems in the study region.

  11. Atmospheric iron deposition: global distribution, variability, and human perturbations.

    Science.gov (United States)

    Mahowald, Natalie M; Engelstaedter, Sebastian; Luo, Chao; Sealy, Andrea; Artaxo, Paulo; Benitez-Nelson, Claudia; Bonnet, Sophie; Chen, Ying; Chuang, Patrick Y; Cohen, David D; Dulac, Francois; Herut, Barak; Johansen, Anne M; Kubilay, Nilgun; Losno, Remi; Maenhaut, Willy; Paytan, Adina; Prospero, Joseph M; Shank, Lindsey M; Siefert, Ronald L

    2009-01-01

    Atmospheric inputs of iron to the open ocean are hypothesized to modulate ocean biogeochemistry. This review presents an integration of available observations of atmospheric iron and iron deposition, and also covers bioavailable iron distributions. Methods for estimating temporal variability in ocean deposition over the recent past are reviewed. Desert dust iron is estimated to represent 95% of the global atmospheric iron cycle, and combustion sources of iron are responsible for the remaining 5%. Humans may be significantly perturbing desert dust (up to 50%). The sources of bioavailable iron are less well understood than those of iron, partly because we do not know what speciation of the iron is bioavailable. Bioavailable iron can derive from atmospheric processing of relatively insoluble desert dust iron or from direct emissions of soluble iron from combustion sources. These results imply that humans could be substantially impacting iron and bioavailable iron deposition to ocean regions, but there are large uncertainties in our understanding.

  12. [Characteristics of atmospheric nitrogen wet deposition in Beijing urban area].

    Science.gov (United States)

    He, Cheng-Wu; Ren, Yu-Fen; Wang, Xiao-Ke; Mao, Yu-Xiang

    2014-02-01

    With the ion-exchange resin method, the atmospheric nitrogen wet deposition in Beijing urban area within the Fifth Ring Road was investigated from June to October, 2012. The relationship between atmospheric nitrogen wet deposition and rainfall precipitation was investigated, the differences of nitrogen wet deposition in different months, different ring roads (the Fifth Ring Road, the Fourth Ring Road, the Third Ring Road and the Second Ring Road) and different functional areas (institutes and colleges district, ring-road, residential areas, railway station and public garden) were also investigated. The results showed that the average value and standard deviation of ammonia-nitrogen, nitrate-nitrogen and nitrite-nitrogen were significantly different during different months in 2012. The atmospheric nitrite nitrogen deposition first decreased and then increased, the maximum value appeared in September. The positive relationships between ammonia nitrogen (nitrate nitrogen) and mean monthly precipitation and negative relationships between nitrite nitrogen and mean monthly precipitation were both significant (P depositions of ring-road and railway station were higher than other functional areas, but only the nitrite nitrogen deposition had obvious regional difference. The differences of the three nitrogen depositions among different ring roads were all not significant and it meant that the nitrogen wet deposition was equally distributed in Beijing urban area. PMID:24812938

  13. Biomonitoring trace element atmospheric deposition using lichens in China

    International Nuclear Information System (INIS)

    Concentrations of 34 elements, Ag, As, Au, Ba, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Mo, Na, Nd, Ni, Rb, Ru, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Tm, U, W, Yb, and Zn were determined by instrumental neutron activation analysis (INAA) in the early preserved epiphytic lichens (Parmotrema recticulata) from the remote Southwestern China area in 1960s, 1980s, and 1990s. The concentrations of Ag, As, Ce, Cr, Cs, Eu, Fe, Hf, La, Nd, Ni, Sc, Se, Sm, Tb, U, Yb, and Zn were dropped down by the temporal prolonation. The elemental concentration levels obtained from the organisms indicate that the extent of heavy metal atmospheric deposition among the sampling sites was declining during the past decades. (author)

  14. Atmospheric transport and wet deposition of ammonium in North Carolina

    Science.gov (United States)

    Walker, John T.; Aneja, Viney P.; Dickey, David A.

    Wet deposition and transport analysis has been performed for ammonium (NH 4+) in North Carolina, USA. Multiple regression analysis is employed to model the temporal trend and seasonality in monthly volume-weighted mean NH 4+ concentrations in precipitation from 1983 to 1996 at six National Atmospheric Deposition Program/National Trends Network (NADP/NTN) sites. A significant ( ppopulated network of swine and poultry operations. This trend is positively correlated with increasing ammonia (NH 3) emissions related to the vigorous growth of North Carolina's swine population since 1990, particularly in the state's Coastal Plain region. A source-receptor regression model, which utilizes weekly NH 4+ concentrations in precipitation in conjunction with boundary layer air mass back trajectories, is developed to statistically test for the influence of a particular NH 3 source region on NH 4+ concentrations at surrounding NADP/NTN sites for the years 1995-1996. NH 3 emissions from this source region, primarily evolving from swine and poultry operations, are found to increase NH 4+ concentration in precipitation at sites up to ≈80 km away. At the Scotland County (NC36) and Wake County (NC41) sites, mean NH 4+ concentrations show increases of at least 44% for weeks during which 25% or more back trajectories are influenced by this source region.

  15. Atmospheric deposition of nitrogen and sulfur in Louisiana

    Science.gov (United States)

    Zhang, H.; Guo, H.

    2015-12-01

    Wet deposition and dry deposition reduce their concentrations of sulfur and nitrogen contained air pollutants in atmosphere, but lead to increase of sulfur and nitrogen fluxes to the surface. Atmospheric deposition of sulfur and nitrogen can lead to acidification of surface water bodies (lakes, rivers, and coasts) and subsequent damage to aquatic ecosystems as well as damage to forests and vegetation. Louisiana has abundant water resources with approximately 11% of the total surface area composed of water bodies. It is important to protect water resources from excessive atmospheric deposition of sulfur and nitrogen. However, the information obtained from the observation systems for understanding the deposition of sulfur and nitrogen and the adverse effects in Louisiana is limited. This study uses a source-oriented CMAQ model to simulate emission, formation, transport, and deposition of sulfur and nitrogen species in Louisiana. WRF is used to generate the meteorological inputs and SMOKE is used to generate the emissions based on national emission inventory (NEI). The forms and quantities of sulfur and nitrogen deposition from wet and dry processes in Louisiana will be discovered. The spatial and temporal variations of sulfur and nitrogen fluxes will be quantified and contributions of major source sectors or source regions will be quantified.

  16. Operational mapping of atmospheric nitrogen deposition to the Baltic Sea

    Directory of Open Access Journals (Sweden)

    O. Hertel

    2003-01-01

    Full Text Available A new model system for mapping and forecasting nitrogen deposition to the Baltic Sea has been developed. The system is based on the Lagrangian variable scale transport-chemistry model ACDEP (Atmospheric Chemistry and Deposition model, and aims at delivering deposition estimates to be used as input to marine ecosystem models. The system is tested by comparison of model results to measurements from monitoring stations around the Baltic Sea. The comparison shows that observed annual mean ambient air concentrations and wet depositions are well reproduced by the model. Diurnal mean concentrations of NHx (sum of NH3 and NH4+ and NO2 are fairly well reproduced, whereas concentrations of total nitrate (sum of HNO3 and NO3- are somewhat overestimated. Wet depositions of nitrate and ammonia are fairly well described for annual mean values, whereas the discrepancy is high for the monthly mean values and the wet depositions are rather poorly described concerning the diurnal mean values. The model calculations show that the annual atmospheric nitrogen deposition has a pronounced south--north gradient with depositions in the range about 1.0 T N km-2 in the south and 0.2 T N km-2 in the north. The results show that in 1999 the maximum diurnal mean deposition to the Danish waters appeared during the summer in the algae growth season. For the northern parts of the Baltic the highest depositions were distributed over most of the year. Total deposition to the Baltic Sea was for the year 1999 estimated to 318 kT N for an area of 464 406 km2 equivalent to an average deposition of 684 kg N/km2.

  17. Atmospheric Data Package for the Composite Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Napier, Bruce A.; Ramsdell, James V.

    2005-09-01

    The purpose of this data package is to summarize our conceptual understanding of atmospheric transport and deposition, describe how this understanding will be simplified for numerical simulation as part of the Composite Analysis (i.e., implementation model), and finally to provide the input parameters needed for the simulations.

  18. Atmospheric Deposition: Sampling Procedures, Analytical Methods, and Main Recent Findings from the Scientific Literature

    Directory of Open Access Journals (Sweden)

    M. Amodio

    2014-01-01

    Full Text Available The atmosphere is a carrier on which some natural and anthropogenic organic and inorganic chemicals are transported, and the wet and dry deposition events are the most important processes that remove those chemicals, depositing it on soil and water. A wide variety of different collectors were tested to evaluate site-specificity, seasonality and daily variability of settleable particle concentrations. Deposition fluxes of POPs showed spatial and seasonal variations, diagnostic ratios of PAHs on deposited particles, allowed the discrimination between pyrolytic or petrogenic sources. Congener pattern analysis and bulk deposition fluxes in rural sites confirmed long-range atmospheric transport of PCDDs/Fs. More and more sophisticated and newly designed deposition samplers have being used for characterization of deposited mercury, demonstrating the importance of rain scavenging and the relatively higher magnitude of Hg deposition from Chinese anthropogenic sources. Recently biological monitors demonstrated that PAH concentrations in lichens were comparable with concentrations measured in a conventional active sampler in an outdoor environment. In this review the authors explore the methodological approaches used for the assessment of atmospheric deposition, from the analysis of the sampling methods, the analytical procedures for chemical characterization of pollutants and the main results from the scientific literature.

  19. Modified drug release using atmospheric pressure plasma deposited siloxane coatings

    Science.gov (United States)

    Dowling, D. P.; Maher, S.; Law, V. J.; Ardhaoui, M.; Stallard, C.; Keenan, A.

    2016-09-01

    This pilot study evaluates the potential of atmospheric plasma polymerised coatings to modify the rate of drug release from polymeric substrates. The antibiotic rifampicin was deposited in a prototype multi-layer drug delivery system, consisting of a nebulized layer of active drug between a base layer of TEOS deposited on a plastic substrate (polystyrene) and an overlying layer of plasma polymerised PDMS. The polymerised TEOS and PDMS layers were deposited using a helium atmospheric plasma jet system. Elution of rifampicin was measured using UV-VIS spectroscopy, in addition to a antimicrobial well diffusion assay with an established indicator organism. The multi-layered plasma deposited coatings significantly extended the duration of release of the rifampicin from 24 h for the uncoated polymer to 144 h for the coated polymer.

  20. Atmospheric nitrogen in the Mississippi River Basin - Amissions, deposition and transport

    Science.gov (United States)

    Lawrence, G.B.; Goolsby, D.A.; Battaglin, W.A.; Stensland, G.J.

    2000-01-01

    Atmospheric deposition of nitrogen has been cited as a major factor in the nitrogen saturation of forests in the north-eastern United States and as a contributor to the eutrophication of coastal waters, including the Gulf of Mexico near the mouth of the Mississippi River. Sources of nitrogen emissions and the resulting spatial patterns of nitrogen deposition within the Mississippi River Basin, however, have not been fully documented. An assessment of atmospheric nitrogen in the Mississippi River Basin was therefore conducted in 1998-1999 to: (1) evaluate the forms in which nitrogen is deposited from the atmosphere; (2) quantify the spatial distribution of atmospheric nitrogen deposition throughout the basin; and (3) relate locations of emission sources to spatial deposition patterns to evaluate atmospheric transport. Deposition data collected through the NADP/NTN (National Atmospheric Deposition Program/National Trends Network) and CASTNet (Clean Air Status and Trends Network) were used for this analysis. NO(x) Tier 1 emission data by county was obtained for 1992 from the US Environmental Protection Agency (Emissions Trends Viewer CD, 1985-1995, version 1.0, September 1996) and NH3 emissions data was derived from the 1992 Census of Agriculture (US Department of Commerce. Census of Agriculture, US Summary and County Level Data, US Department of Commerce, Bureau of the Census. Geographic Area series, 1995:1b) or the National Agricultural Statistics Service (US Department of Agriculture. National Agricultural Statistics Service Historical Data. Accessed 7/98 at URL, 1998. http://www.usda.gov/nass/pubs/hisdata.htm). The highest rates of wet deposition of NO3- were in the north-eastern part of the basin, downwind of electric utility plants and urban areas, whereas the highest rates of wet deposition of NH4+ were in Iowa, near the center of intensive agricultural activities in the Midwest. The lowest rates of atmospheric nitrogen deposition were on the western (windward

  1. Atmospheric deposition of heavy metals (Cu, Zn, Cd and Pb) in Varanasi City, India.

    Science.gov (United States)

    Sharma, Rajesh Kumar; Agrawal, Madhoolika; Marshall, Fiona M

    2008-07-01

    Rapid growth in urbanization and industrialization in developing countries may significantly contribute in heavy metal contamination of vegetables through atmospheric depositions. In the present study, an assessment was made to investigate the spatial and seasonal variations in deposition rates of heavy metals and its contribution to contamination of palak (Beta vulgaris). Samples of bulk atmospheric deposits and Beta vulgaris for analysis of Cu, Zn, Cd and Pb were collected from different sampling locations differing in traffic density and land use patterns. The results showed that the sampling locations situated in industrial or commercial areas with heavy traffic load showed significantly elevated levels of Cu, Zn and Cd deposition rate as compared to those situated in residential areas with low traffic load. The deposition rates of Cu, Zn and Cd were significantly higher in summer and winter as compared to rainy season, however, Pb deposition rate was significantly higher in rainy and summer seasons as compared to winter season. Atmospheric depositions have significantly elevated the levels of heavy metals in B. vulgaris collected during evening as compared to those collected in morning hours. The study further showed that local population has maximum exposure to Cd contamination through consumption of B. vulgaris. The present study clearly points out the urban and industrial activities of a city have potential to elevate the levels of heavy metals in the atmospheric deposits, which may consequently contaminate the food chain and thus posing health risk to the local population. PMID:17879134

  2. Relation between forest vegetation, atmospheric deposition and site conditions at regional and European scales

    International Nuclear Information System (INIS)

    Several monitoring programs have been set up to assess effects of atmospheric deposition on forest ecosystems. The aim of the present study was to evaluate effects on the understorey vegetation, based on the first round of a regional (the Netherlands) and a European forest monitoring program. A multivariate statistical analysis showed surprisingly similar results for both data sets; the vegetation appeared to be largely determined by the 'traditional' factors soil, climate, and tree species, but there was a small but statistically significant effect of atmospheric deposition. The effects of deposition include a slight shift towards nitrophytic species at high N deposition in the European network, and towards acidophytic species at high S-deposition in the Dutch network. The relatively small effect of atmospheric deposition is understandable in view of the very large natural variation in environmental conditions. Time series of both vegetation and environment are needed to assess deposition effects in detail. - There is a small but noticeable effect of anthropogenic atmospheric deposition on forest vegetation in Europe.

  3. Operational mapping of atmospheric nitrogen deposition to the Baltic Sea

    Directory of Open Access Journals (Sweden)

    O. Hertel

    2003-07-01

    Full Text Available A new model system for mapping and forecasting nitrogen deposition to the Baltic Sea has been developed. The system is based on the Lagrangian variable scale transport-chemistry model ACDEP (Atmospheric Chemistry and Deposition model, and aims at delivering deposition estimates to be used as input to marine ecosystem models. The system is tested by comparison of model results to measurements from monitoring stations around the Baltic Sea. The comparison shows that observed annual mean ambient air concentrations and wet depositions are well reproduced by the model. Diurnal mean concentrations of NHx (sum of  NH3 and NH4 and NO2 are fairly well reproduced, whereas concentrations of total nitrate (sum of HNO3 and NO3 are somewhat overestimated by the model. Wet depositions of nitrate and ammonia are fairly well described for annual mean values, whereas the discrepancy is high for the monthly mean values and the wet depositions are rather poorly described concerning the diurnal mean values. The model calculations show that the atmospheric nitrogen deposition has a pronounced south – north gradient with depositions in the range about 1.0 tonnes N km−2 in south and 0.2 tonnes N km−2 in north. The model results show that in 2000 the maximum deposition to the Danish waters appeared during the summer in the algae growth season. For the northern parts of the Baltic the highest depositions were distributed over most of the year.

  4. Total atmospheric mercury deposition in forested areas in South Korea

    Science.gov (United States)

    Han, Jin-Su; Seo, Yong-Seok; Kim, Moon-Kyung; Holsen, Thomas M.; Yi, Seung-Muk

    2016-06-01

    In this study, mercury (Hg) was sampled weekly in dry and wet deposition and throughfall and monthly in litterfall, and as it was volatilized from soil from August 2008 to February 2010 to identify the factors influencing the amount of atmospheric Hg deposited to forested areas in a temperate deciduous forest in South Korea. For this location there was no significant correlation between the estimated monthly dry deposition flux (litterfall + throughfall - wet deposition) (6.7 µg m-2 yr-1) and directly measured dry deposition (9.9 µg m-2 yr-1) likely due primarily to Hg losses from the litterfall collector. Dry deposition fluxes in cold seasons (fall and winter) were lower than in warmer seasons (spring and summer). The volume-weighted mean (VWM) Hg concentrations in both precipitation and throughfall were highest in winter, likely due to increased scavenging by snow events. Since South Korea experiences abundant rainfall in summer, VWM Hg concentrations in summer were lower than in other seasons. Litterfall fluxes were highest in the late fall to early winter, when leaves were dropped from the trees (September to November). The cumulative annual Hg emission flux from soil was 6.8 µg m-2 yr-1. Based on these data, the yearly deposition fluxes of Hg calculated using two input approaches (wet deposition + dry deposition or throughfall + litterfall) were 6.8 and 3.6 µg m-2 yr-1, respectively. This is the first reported study which measured the amount of atmospheric Hg deposited to forested areas in South Korea, and thus our results provide useful information to compare against data related to Hg fate and transport in this part of the world.

  5. Atmospheric Deposition of Phosphorus to the Everglades: Concepts, Constraints, and Published Deposition Rates for Ecosystem Management

    Directory of Open Access Journals (Sweden)

    Garth W. Redfield

    2002-01-01

    Full Text Available This paper summarizes concepts underlying the atmospheric input of phosphorus (P to ecosystems, published rates of P deposition, measurement methods, and approaches to future monitoring and research. P conveyed through the atmosphere can be a significant nutrient source for some freshwater and marine ecosystems. Particle sources and sinks at the land-air interface produce variation in P deposition from the atmosphere across temporal and spatial scales. Natural plant canopies can affect deposition rates by changing the physical environment and surface area for particle deposition. Land-use patterns can alter P deposition rates by changing particle concentrations in the atmosphere. The vast majority of P in dry atmospheric deposition is conveyed by coarse (2.5 to 10 μm and giant (10 to 100 μm particles, and yet these size fractions represent a challenge for long-term atmospheric monitoring in the absence of accepted methods for routine sampling. Most information on P deposition is from bulk precipitation collectors and wet/dry bucket sampling, both with questionable precision and accuracy. Most published annual rates of P deposition are gross estimates derived from bulk precipitation sampling in locations around the globe and range from about 5 to well over 100 mg P m–2 year–1, although most inland ecosystems receive between 20 and 80 mg P m–2 year–1. Rates below 30 mg P m–2 year–1 are found in remote areas and near coastlines. Intermediate rates of 30 to 50 mg P m–2 year–1 are associated with forests or mixed land use, and rates of 50 to 100 mg P m–2 year–1 or more are often recorded from urban or agricultural settings. Comparison with other methods suggests that these bulk precipitation estimates provide crude boundaries around actual P deposition rates for various land uses. However, data screening cannot remove all positive bias caused by contamination of bucket or bulk collectors. As a consequence, continued sampling

  6. Modeling the global atmospheric transport and deposition of mercury to the Great Lakes

    Directory of Open Access Journals (Sweden)

    Mark D. Cohen

    2016-07-01

    Full Text Available Abstract Mercury contamination in the Great Lakes continues to have important public health and wildlife ecotoxicology impacts, and atmospheric deposition is a significant ongoing loading pathway. The objective of this study was to estimate the amount and source-attribution for atmospheric mercury deposition to each lake, information needed to prioritize amelioration efforts. A new global, Eulerian version of the HYSPLIT-Hg model was used to simulate the 2005 global atmospheric transport and deposition of mercury to the Great Lakes. In addition to the base case, 10 alternative model configurations were used to examine sensitivity to uncertainties in atmospheric mercury chemistry and surface exchange. A novel atmospheric lifetime analysis was used to characterize fate and transport processes within the model. Model-estimated wet deposition and atmospheric concentrations of gaseous elemental mercury (Hg(0 were generally within ∼10% of measurements in the Great Lakes region. The model overestimated non-Hg(0 concentrations by a factor of 2–3, similar to other modeling studies. Potential reasons for this disagreement include model inaccuracies, differences in atmospheric Hg fractions being compared, and the measurements being biased low. Lake Erie, downwind of significant local/regional emissions sources, was estimated by the model to be the most impacted by direct anthropogenic emissions (58% of the base case total deposition, while Lake Superior, with the fewest upwind local/regional sources, was the least impacted (27%. The U.S. was the largest national contributor, followed by China, contributing 25% and 6%, respectively, on average, for the Great Lakes. The contribution of U.S. direct anthropogenic emissions to total mercury deposition varied between 46% for the base case (with a range of 24–51% over all model configurations for Lake Erie and 11% (range 6–13% for Lake Superior. These results illustrate the importance of atmospheric

  7. Accumulation of atmospheric deposition of As, Cd and Pb by bush bean plants

    International Nuclear Information System (INIS)

    Bush bean (Phaseolus vulgaris) was exposed to atmospheric deposition of As, Cd and Pb in a polluted and a reference area. The atmospheric deposition of these elements was significantly related to the concentrations in leaves, stems and pods at green harvest. Surprisingly there was also a clear relation for As and Pb in the seeds at dry harvest, even though these seeds were covered by the husks. Root uptake of accumulated atmospheric deposits was not likely in such a short term experiment, as confirmed by the fact that soil pore water analysis did not reveal significant differences in trace element concentrations in the different exposure areas. For biomonitoring purposes, the leaves of bush bean are the most suitable, but also washed or unwashed pods can be used. This means that the obtained relationships are suitable to estimate the transfer of airborne trace elements in the food chain via bush bean. - Highlights: • Atmospheric deposition of trace elements accumulates in bean leaves, stems and pods. • Also thoroughly washed green pods are suitable for biomonitoring. • Even the non-exposed bean seeds accumulate As and Pb deposits to some extend. • A migration of trace elements from the husks to the seeds is most likely. - In a polluted area, atmospheric deposition of trace elements on the above-ground plant parts is influencing their concentration, even in the seeds

  8. Impact of atmospheric nitrogen deposition on phytoplankton productivity in the South China Sea

    Science.gov (United States)

    Kim, Tae-Wook; Lee, Kitack; Duce, Robert; Liss, Peter

    2014-05-01

    The impacts of anthropogenic nitrogen (N) deposition on the marine N cycle are only now being revealed, but the magnitudes of those impacts are largely unknown in time and space. The South China Sea (SCS) is particularly subject to high anthropogenic N deposition, because the adjacent countries are highly populated and have rapidly growing economies. Analysis of data sets for atmospheric N deposition, satellite chlorophyll-a (Chl-a), and air mass back trajectories reveals that the transport of N originating from the populated east coasts of China and Indonesia, and its deposition to the ocean, has been responsible for the enhancements of Chl-a in the SCS. We found that atmospheric N deposition contributed approximately 20% of the annual biological new production in the SCS. The airborne contribution of N to new production in the SCS is expected to grow considerably in the coming decades.

  9. Atmospheric concentrations and deposition fluxes of 7Be and 210Pb at Rokkasho village, Japan

    International Nuclear Information System (INIS)

    Biweekly atmospheric concentrations and deposition fluxes of 7Be and 210Pb were measured at Rokkasho, Aomori Prefecture, Japan, from March 2000 to March 2006, to clarify their regional features. The atmospheric concentration of 7Be was low in summer and winter and high in spring and fall, and that of 210Pb was low in summer and high in winter. Negative correlations were between the atmospheric 7Be or 210Pb concentrations and precipitation in the sampling periods, and that suggested that both nuclides were removed from the atmosphere mainly by wet deposition (rain or snow). The deposition fluxes of 7Be and 210Pb were low in summer and high in winter to spring. Deposition fluxes of 7Be and 210Pb positively correlated to precipitation. From the results of the power spectral analysis by fast Fourier transform, annual periodicities of 7Be and 210Pb deposition at Rokkasho could be classified as a double peak distribution pattern and single peak distribution pattern, respectively. Backward trajectories for 72 h were calculated every 6 h in order to clarify the relation of air mass transport course and atmospheric concentrations of 210Pb. The results showed that atmospheric 210Pb concentrations were strongly affected by air mass from the northern Asian continental area above 40degN. (author)

  10. The atmospheric chemical vapour deposition of coatings on glass

    CERN Document Server

    Sanderson, K D

    1996-01-01

    The deposition of thin films of indium oxide, tin doped indium oxide (ITO) and titanium nitride for solar control applications have been investigated by Atmospheric Chemical Vapour Deposition (APCVD). Experimental details of the deposition system and the techniques used to characterise the films are presented. Results from investigations into the deposition parameters, the film microstructure and film material properties are discussed. A range of precursors were investigated for the deposition of indium oxide. The effect of pro-mixing the vaporised precursor with an oxidant source and the deposition temperature has been studied. Polycrystalline In sub 2 O sub 3 films with a resistivity of 1.1 - 3x10 sup - sup 3 OMEGA cm were obtained with ln(thd) sub 3 , oxygen and nitrogen. The growth of ITO films from ln(thd) sub 3 , oxygen and a range of tin dopants is also presented. The effect of the dopant precursor, the doping concentration, deposition temperature and the effect of additives on film growth and microstr...

  11. Atmospheric deposition of phosphorus to land and freshwater.

    Science.gov (United States)

    Tipping, E; Benham, S; Boyle, J F; Crow, P; Davies, J; Fischer, U; Guyatt, H; Helliwell, R; Jackson-Blake, L; Lawlor, A J; Monteith, D T; Rowe, E C; Toberman, H

    2014-07-01

    We compiled published and newly-obtained data on the directly-measured atmospheric deposition of total phosphorus (TP), filtered total phosphorus (FTP), and inorganic phosphorus (PO4-P) to open land, lakes, and marine coasts. The resulting global data base includes data for c. 250 sites, covering the period 1954 to 2012. Most (82%) of the measurement locations are in Europe and North America, with 44 in Africa, Asia, Oceania, and South-Central America. The deposition rates are log-normally distributed, and for the whole data set the geometric mean deposition rates are 0.027, 0.019 and 0.14 g m(-2) a(-1) for TP, FTP and PO4-P respectively. At smaller scales there is little systematic spatial variation, except for high deposition rates at some sites in Germany, likely due to local agricultural sources. In cases for which PO4-P was determined as well as one of the other forms of P, strong parallels between logarithmic values were found. Based on the directly-measured deposition rates to land, and published estimates of P deposition to the oceans, we estimate a total annual transfer of P to and from the atmosphere of 3.7 Tg. However, much of the phosphorus in larger particles (principally primary biological aerosol particles) is probably redeposited near to its origin, so that long-range transport, important for tropical forests, large areas of peatland and the oceans, mainly involves fine dust from deserts and soils, as described by the simulations of Mahowald et al. (Global Biogeochemical Cycles 22, GB4026, 2008). We suggest that local release to the atmosphere and subsequent deposition bring about a pseudo-diffusive redistribution of P in the landscape, with P-poor ecosystems, for example ombrotrophic peatlands and oligotrophic lakes, gaining at the expense of P-rich ones. Simple calculations suggest that atmospheric transport could bring about significant local redistribution of P among terrestrial ecosystems. Although most atmospherically transported P is natural

  12. Effect of atmospheric electricity on dry deposition of airborne particles from atmosphere

    Science.gov (United States)

    Tammet, H.; Kimmel, V.; Israelsson, S.

    The electric mechanism of dry deposition is well known in the case of unattached radon daughter clusters that are unipolar charged and of high mobility. The problematic role of the electric forces in deposition of aerosol particles is theoretically examined by comparing the fluxes of particles carried by different deposition mechanisms in a model situation. The electric mechanism of deposition appears essential for particles of diameter 10-200 nm in conditions of low wind speed. The electric flux of fine particles can be dominant on the tips of leaves and needles even in a moderate atmospheric electric field of a few hundred V m -1 measured over the plane ground surface. The electric deposition is enhanced under thunderclouds and high voltage power lines. Strong wind suppresses the relative role of the electric deposition when compared with aerodynamic deposition. When compared with diffusion deposition the electric deposition appears less uniform: the precipitation particulate matter on the tips of leaves and especially on needles of top branches of conifer trees is much more intensive than on the ground surface and electrically shielded surfaces of plants. The knowledge of deposition geometry could improve our understanding of air pollution damage to plants.

  13. Atmospheric Deposition and Critical Loads for Nitrogen and Metals in Arctic Alaska: Review and Current Status

    Science.gov (United States)

    Linder, Greg; Brumbaugh, William G.; Neitlich, Peter; Little, Edward

    2013-01-01

    To protect important resources under their bureau’s purview, the United States National Park Service’s (NPS) Arctic Network (ARCN) has developed a series of “vital signs” that are to be periodically monitored. One of these vital signs focuses on wet and dry deposition of atmospheric chemicals and further, the establishment of critical load (CL) values (thresholds for ecological effects based on cumulative depositional loadings) for nitrogen (N), sulfur, and metals. As part of the ARCN terrestrial monitoring programs, samples of the feather moss Hylocomium splendens are being col- lected and analyzed as a cost-effective means to monitor atmospheric pollutant deposition in this region. Ultimately, moss data combined with refined CL values might be used to help guide future regulation of atmospheric contaminant sources potentially impacting Arctic Alaska. But first, additional long-term studies are needed to determine patterns of contaminant deposition as measured by moss biomonitors and to quantify ecosystem responses at particular loadings/ ranges of contaminants within Arctic Alaska. Herein we briefly summarize 1) current regulatory guidance related to CL values 2) derivation of CL models for N and metals, 3) use of mosses as biomonitors of atmospheric deposition and loadings, 4) preliminary analysis of vulnerabilities and risks associated with CL estimates for N, 5) preliminary analysis of existing data for characterization of CL values for N for interior Alaska and 6) implications for managers and future research needs.

  14. The deposition of radioiodine onto rice plant from atmosphere

    International Nuclear Information System (INIS)

    Radiation dose estimations are usually made with the aid of assessment models in which model parameters such as the transfer factors of radionuclides from one environmental compartment to another are involved. In simple models the parameters are often described as the concentration ratio of a radionuclide between two compartments, when the system is under equilibrium condition. In this paper, the authors introduce the values of the parameters of radioiodine obtained by tracer experiments. Laboratory experiments on the transfer parameters of radionuclides from the atmosphere to rice plant were carried out in the atmosphere-to-crops system (deposition pathway). It is known that the typical chemical species of gaseous iodine in the atmosphere are elemental iodine (I2) and methyliodide (CH3I). The deposition characteristics of both chemical species of gaseous iodine to rice grains were obtained. Mass normalized deposition velocity (VD) and grain number normalized deposition velocity (VS) of gaseous elemental iodine (I2) and also methyliodide (CH3I) on unhulled rice were measured. Both VD and VS of methyliodide were about one percent of those of elemental iodine. Distribution pattern of methyliodide between unhulled rice and brown rice was significantly lower than that of elemental one. For wet deposition, we investigated the retention of radioiodines (iodide [I-] and iodate [IO3-] on rice grains and their translocation from the surface of the grains to brown rice. Though the ears were dipped into the solution containing 125I- or 125IO3- more than 15 min., both iodine species in the solutions were hardly taken up to the rice grains. The transfer rates of iodide and iodate, which are defined as 'the amount of the iodine in brown rice' divided by 'the amount of iodide in unhulled rice' were about 0.015 and 0.04, respectively. The rates were not changed with time after the radioiodine application. (author)

  15. Atmospheric deposition of radioactive cesium (137Cs) associated with dust events in East Asia

    International Nuclear Information System (INIS)

    Since the cessation of atmospheric nuclear testing in 1980, there has been no known serious atmospheric contamination by radioactive cesium (sup(137)Cs) apart from the Chernobyl nuclear reactor accident in 1986. There now remain only small amounts of anthropogenic radionuclides in the atmosphere that can be directly related to past testing. However, sup(137)Cs is still regularly found in atmospheric deposition samples in Japan. In this study, we analyzed sup(137)Cs monitoring data, meteorological data, and field survey results to investigate the recent transport and deposition of sup(137)Cs associated with dust phenomena. Monthly records of nationwide sup(137)Cs deposition in Japan during the 1990s show a consistent seasonal variation, with higher levels of deposition occurring in spring. In March 2002, an unexpectedly high amount of sup(137)Cs was deposited in the northwestern coastal area of Japan at the same time as an Asian dust event was observed. Analysis of land-based weather data showed that sandstorms and other dust-raising phenomena also occurred in March 2002 over areas of Mongolia and northeastern China where grassland and shrubs predominated. Furthermore, radioactivity measurements showed sup(137)Cs enrichment in the surface layer of grassland soils in the areas affected by these sandstorms. These results suggest that grasslands are potential sources of sup(137)Cs-bearing dust. Continued desertification of the East Asian continent in response to recent climate change can be expected to result in an increase in sup(137)Cs-bearing soil particles in the atmosphere, and their subsequent re-deposition in Japan. However, soil dust is also raised around Japanese monitoring sites by the strong winds that are common in Japan in spring, and this local dust might also contribute to sup(137)Cs deposition in Japan. To estimate the relative contributions of local and distant dust events to the total sup(137)Cs deposition, we monitored deposition of mineral particles

  16. Impact of increased anthropogenic atmospheric nitrogen deposition on ocean biogeochemistry

    Science.gov (United States)

    Yang, Simon; Gruber, Nicolas

    2015-04-01

    In the last century, the strong increase in anthropogenic emissions and agricultural activities brought about a tripling in atmospheric nitrogen deposition (AND) rates to oceans. There is growing evidence for a strong fingerprint of increased AND on aquatic systems. Increases in excess N over P (N*) have been attributed to the growing anthropogenically sourced N-deposition in the North western Pacific (Kim et al. 2011) and the North Pacific (Kim et al. 2014). In this study, we use the ocean component of the global earth system model CESM and forced it with transient atmospheric nitrogen deposition from 1850 to 2000 (Lamarque et al. 2013) to study the impact of increased N-deposition on ocean biogeochemistry. We simulate detectable signals in N* in the northern hemisphere as well as a complex pattern of increases and decreases in ocean productivity, with the former causing an expansion of oxygen minimum zones and an increase in water column denitrification. The increase in AND also reduces the ecological niches for N2-fixers, causing a substantial decrease in global ocean N-fixation. Despite this increase in N-loss by denitrification and decrease in N-gain by N-fixation, the increase in AND has put the global marine N-budget severely out of balance ( 10 TgN.yr-1). Finally, we extend our simulation to 2100 using the RCP 8.5 emission scenario to find that these changes will probably grow in the future.

  17. Gas permeation barriers deposited by atmospheric pressure plasma enhanced atomic layer deposition

    International Nuclear Information System (INIS)

    This paper reports on aluminum oxide (Al2O3) thin film gas permeation barriers fabricated by atmospheric pressure atomic layer deposition (APPALD) using trimethylaluminum and an Ar/O2 plasma at moderate temperatures of 80 °C in a flow reactor. The authors demonstrate the ALD growth characteristics of Al2O3 films on silicon and indium tin oxide coated polyethylene terephthalate. The properties of the APPALD-grown layers (refractive index, density, etc.) are compared to that deposited by conventional thermal ALD at low pressures. The films films deposited at atmospheric pressure show water vapor transmission rates as low as 5 × 10−5 gm−2d−1

  18. Gas permeation barriers deposited by atmospheric pressure plasma enhanced atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Lukas, E-mail: lhoffmann@uni-wuppertal.de; Theirich, Detlef; Hasselmann, Tim; Räupke, André; Schlamm, Daniel; Riedl, Thomas, E-mail: t.riedl@uni-wuppertal.de [Institute of Electronic Devices, University of Wuppertal, Rainer-Gruenter-Str. 21, 42119 Wuppertal (Germany)

    2016-01-15

    This paper reports on aluminum oxide (Al{sub 2}O{sub 3}) thin film gas permeation barriers fabricated by atmospheric pressure atomic layer deposition (APPALD) using trimethylaluminum and an Ar/O{sub 2} plasma at moderate temperatures of 80 °C in a flow reactor. The authors demonstrate the ALD growth characteristics of Al{sub 2}O{sub 3} films on silicon and indium tin oxide coated polyethylene terephthalate. The properties of the APPALD-grown layers (refractive index, density, etc.) are compared to that deposited by conventional thermal ALD at low pressures. The films films deposited at atmospheric pressure show water vapor transmission rates as low as 5 × 10{sup −5} gm{sup −2}d{sup −1}.

  19. Modeling Planetary Atmospheric Energy Deposition By Energetic Ions

    Science.gov (United States)

    Parkinson, Christopher; Bougher, Stephen; Gronoff, Guillaume; Barthelemy, Mathieu

    2016-07-01

    The structure, dynamics, chemistry, and evolution of planetary upper atmospheres are in large part determined by the available sources of energy. In addition to the solar EUV flux, the solar wind and solar energetic particle (SEP) events are also important sources. Both of these particle populations can significantly affect an atmosphere, causing atmospheric loss and driving chemical reactions. Attention has been paid to these sources from the standpoint of the radiation environment for humans and electronics, but little work has been done to evaluate their impact on planetary atmospheres. At unmagnetized planets or those with crustal field anomalies, in particular, the solar wind and SEPs of all energies have direct access to the atmosphere and so provide a more substantial energy source than at planets having protective global magnetic fields. Additionally, solar wind and energetic particle fluxes should be more significant for planets orbiting more active stars, such as is the case in the early history of the solar system for paleo-Venus and Mars. Therefore quantification of the atmospheric energy input from the solar wind and SEP events is an important component of our understanding of the processes that control their state and evolution. We have applied a full Lorentz motion particle transport model to study the effects of particle precipitation in the upper atmospheres of Mars and Venus. Such modeling has been previously done for Earth and Mars using a guiding center precipitation model. Currently, this code is only valid for particles with small gyroradii in strong uniform magnetic fields. There is a clear necessity for a Lorentz formulation, hence, a systematic study of the ionization, excitation, and energy deposition has been conducted, including a comparison of the influence relative to other energy sources (namely EUV photons). The result is a robust examination of the influence of energetic ion transport on the Venus and Mars upper atmosphere which

  20. Mechanisms controlling soil carbon sequestration under atmospheric nitrogen deposition

    Energy Technology Data Exchange (ETDEWEB)

    R.L. Sinsabaugh; D.R. Zak; D.L. Moorhead

    2008-02-19

    Increased atmospheric nitrogen (N) deposition can alter the processing and storage of organic carbon in soils. In 2000, we began studying the effects of simulated atmospheric N deposition on soil carbon dynamics in three types of northern temperate forest that occur across a wide geographic range in the Upper Great Lakes region. These ecosystems range from 100% oak in the overstory (black oak-white oak ecosystem; BOWO) to 0% overstory oak (sugar maple-basswood; SMBW) and include the sugar maple-red oak ecosystem (SMRO) that has intermediate oak abundance. The leaf litter biochemistry of these ecosystems range from highly lignified litter (BOWO) to litter of low lignin content (SMBW). We selected three replicate stands of each ecosystem type and established three plots in each stand. Each plot was randomly assigned one of three levels of N deposition (0, 30 & 80 kg N ha-1 y-1) imposed by adding NaNO3 in six equal increments applied over the growing season. Through experiments ranging from the molecular to the ecosystem scales, we produced a conceptual framework that describes the biogeochemistry of soil carbon storage in N-saturated ecosystems as the product of interactions between the composition of plant litter, the composition of the soil microbial community and the expression of extracellular enzyme activities. A key finding is that atmospheric N deposition can increase or decrease the soil C storage by modifying the expression of extracellular enzymes by soil microbial communities. The critical interactions within this conceptual framework have been incorporated into a new class of simulations called guild decomposition models.

  1. Multivariate Analysis of Heavy Metal Element Concentrations in Atmospheric Deposition in Harbin City, Northeast China%哈尔滨市城区大气重金属沉降特征和来源研究

    Institute of Scientific and Technical Information of China (English)

    汤洁; 韩维峥; 李娜; 李昭阳; 卞建民; 李海毅

    2011-01-01

    鉴于大气重金属降尘对城市居民健康存在一定的威胁,针对哈尔滨市从未开展过重金属沉降特征研究的现状,采用被动采样技术共收集大气降尘样品46份,用AFS-230E原子荧光光度计和ICP-AES全谱直读电感耦合等离子发射光谱法测量样品中的重金属元素含量,计算各元素年沉降通量,利用Pearson系数法、主成分分析法、富集因子法进行重金属沉降特征和来源分析.结果表明,Mn和Co元素主要来自于自然源,其余各元素沉降主要由人为源构成,且人为源中占主导地位的是燃煤尘、汽车尘和金属冶金尘.%In order to understand the characteristics of atmospheric heavy metal deposition in Harbin City, 46 deposition samples were collected which were taken using bulk deposition samplers during the period of 2008-2009 (about 365 days). The samples were analyzed for heavy metal concentration by atomic fluorescence spectrometry (AFS) and inductively coupled plasma-atomic spectrometry (ICP-AES). The deposition flux was calculated. Sources analysis was made by the method of principal component analysis (PCA), Pearsons and enrichment factor (EF). The following points can be gained through multivariate analysis. Mn and Co are mostly from natural sources while the others may be brought by coal dust, vehicle emissions and metal smelting.

  2. Contribution of Atmospheric Nitrogen Compounds to N Deposition in a Broadleaf Forest of Southern China

    Institute of Scientific and Technical Information of China (English)

    HU Zheng-Yi; XU Cheng-Kai; ZHOU Li-Na; SUN Ben-Hua; HE Yuan-Qiu; ZHOU Jing; CAO Zhi-Hong

    2007-01-01

    A one-year study in a typical red soil region of southern China was conducted to determine atmospheric nitrogen (N) fluxes of typical N compounds (NH3, NH4-N, NO3-N, and NO2) and contribution of three sources (gas, rainwater, and particles) to N deposition. From July 2003 to June 2004, the total atmospheric N deposition was 70.7 kg N ha-1, with dry deposition accounting for 75% of the total deposition. Dry NH3 deposition accounted for 73% of the dry deposition and 55% of the total deposition. Moreover, NO2 contributed 11% of the dry deposition and 8% of the total deposition. Reduced N compounds (NH+4 and NH3) were the predominate contributors, accounting for 66% of the total deposition. Therefore, atmospheric N deposition should be considered when soil acidification and critical loads of atmospheric deposition on soils are estimated.

  3. Does chronic nitrogen deposition during biomass growth affect atmospheric emissions from biomass burning?

    International Nuclear Information System (INIS)

    Chronic nitrogen deposition has measureable impacts on soil and plant health. We investigate burning emissions from biomass grown in areas of high and low NOx deposition. Gas and aerosol-phase emissions were measured as a function of photochemical aging in an environmental chamber at UC-Riverside. Though aerosol chemical speciation was not available, results indicate a systemic compositional difference between biomass grown in high and low deposition areas. Aerosol emissions from biomass grown in areas of high NOx deposition exhibit a lower volatility than biomass grown in a low deposition area. Furthermore, fuel elemental analysis, NOx emission rates, and aerosol particle number distributions differed significantly between the two sites. Despite the limited scale of fuels explored, there is strong evidence that the atmospheric emissions community must pay attention to the regional air quality of biomass fuels growth areas. (letter)

  4. Atmospherically deposited trace metals from bulk mineral concentrate port operations.

    Science.gov (United States)

    Taylor, Mark Patrick

    2015-05-15

    Although metal exposures in the environment have declined over the last two decades, certain activities and locations still present a risk of harm to human health. This study examines environmental dust metal and metalloid hazards (arsenic, cadmium, lead and nickel) associated with bulk mineral transport, loading and unloading port operations in public locations and children's playgrounds in the inner city of Townsville, northern Queensland. The mean increase in lead on post-play hand wipes (965 μg/m(2)/day) across all sites was more than 10-times the mean pre-play loadings (95 μg/m(2)/day). Maximum loading values after a 10-minute play period were 3012 μg/m(2), more than seven times the goal of 400 μg/m(2) used by the Government of Western Australia (2011). Maximum daily nickel post-play hand loadings (404 μg/m(2)) were more than 26 times above the German Federal Immission Control Act 2002 annual benchmark of 15 μg/m(2)/day. Repeat sampling over the 5-day study period showed that hands and surfaces were re-contaminated daily from the deposition of metal-rich atmospheric dusts. Lead isotopic composition analysis of dust wipes ((208)Pb/(207)Pb and (206)Pb/(207)Pb) showed that surface dust lead was similar to Mount Isa type ores, which are exported through the Port of Townsville. While dust metal contaminant loadings are lower than other mining and smelting towns in Australia, they exceeded national and international benchmarks for environmental quality. The lessons from this study are clear - even where operations are considered acceptable by managing authorities, targeted assessment and monitoring can be used to evaluate whether current management practices are truly best practice. Reassessment can identify opportunities for improvement and maximum environmental and human health protection.

  5. Response of global soil consumption of atmospheric methane to changes in atmospheric climate and nitrogen deposition

    Science.gov (United States)

    Zhuang, Qianlai; Chen, Min; Xu, Kai; Tang, Jinyun; Saikawa, Eri; Lu, Yanyu; Melillo, Jerry M.; Prinn, Ronald G.; McGuire, A. David

    2013-01-01

    Soil consumption of atmospheric methane plays an important secondary role in regulating the atmospheric CH4 budget, next to the dominant loss mechanism involving reaction with the hydroxyl radical (OH). Here we used a process-based biogeochemistry model to quantify soil consumption during the 20th and 21st centuries. We estimated that global soils consumed 32–36 Tg CH4 yr−1 during the 1990s. Natural ecosystems accounted for 84% of the total consumption, and agricultural ecosystems only consumed 5 Tg CH4 yr−1 in our estimations. During the twentieth century, the consumption rates increased at 0.03–0.20 Tg CH4 yr−2 with seasonal amplitudes increasing from 1.44 to 3.13 Tg CH4 month−1. Deserts, shrublands, and xeric woodlands were the largest sinks. Atmospheric CH4 concentrations and soil moisture exerted significant effects on the soil consumption while nitrogen deposition had a moderate effect. During the 21st century, the consumption is predicted to increase at 0.05-1.0 Tg CH4 yr−2, and total consumption will reach 45–140 Tg CH4 yr−1 at the end of the 2090s, varying under different future climate scenarios. Dry areas will persist as sinks, boreal ecosystems will become stronger sinks, mainly due to increasing soil temperatures. Nitrogen deposition will modestly reduce the future sink strength at the global scale. When we incorporated the estimated global soil consumption into our chemical transport model simulations, we found that nitrogen deposition suppressed the total methane sink by 26 Tg during the period 1998–2004, resulting in 6.6 ppb higher atmospheric CH4 mixing ratios compared to without considering nitrogen deposition effects. On average, a cumulative increase of every 1 Tg soil CH4 consumption decreased atmospheric CH4 mixing ratios by 0.26 ppb during the period 1998–2004.

  6. Atmospheric transport and deposition of Indonesian volcanic emissions

    Directory of Open Access Journals (Sweden)

    M. A. Pfeffer

    2005-11-01

    Full Text Available A regional climate model study has been performed to investigate the transport and atmospheric loss rates of emissions from Indonesian volcanoes and the sensitivity of these emissions to meteorological conditions and the solubility of the released emissions. Two experiments were conducted: 1 volcanic sulfur released as primarily SO2 and oxidation to SO42− determined by considering the major tropospheric chemical reactions; and 2 PbCl2 released as an infinitely soluble passive tracer. The first experiment was used to calculate SO2 loss rates from each active volcano resulting in an annual mean loss rate for all volcanoes of 1.1×10−5 s−1, or an e-folding rate of approximately 1 day. SO2 loss rate was found to vary seasonally, be poorly correlated with wind speed, and uncorrelated with temperature or relative humidity. The variability of SO2 loss rates is found to be correlated with the variability of wind speeds, suggesting that it is much more difficult to establish a ''typical'' SO2 loss rate for volcanoes that are exposed to inconsistent winds. Within an average distance of 69 km away from the active Indonesian volcanoes, 53% of SO2 is lost due to conversion to SO42−, 42% due to dry deposition, and 5% is lost due to lateral transport away from the dominant direction of plume travel. The solubility of volcanic emissions in water is shown to have a major influence on their atmospheric transport and deposition. High concentrations of PbCl2 are predicted to be deposited near to the volcanoes while volcanic S travels further away until removal from the atmosphere primarily via the wet deposition of H2SO4. The ratio of the concentration of PbCl2 to SO2 is found to exponentially decay at increasing distance from the volcanoes

  7. Load of soil and water by atmospheric nitrogen deposition

    International Nuclear Information System (INIS)

    After comprehensive retrofitting of power plants with flue gas desulfurization systems has been completed in Germany, nitrogen oxides (NOx) and ammonia became the most important air pollutants. Pollution control measures to reduce the release of these substances which predominantly originate from traffic and agriculture had only marginal success. Some way or other, emissions into the atmosphere return to the ground and entail here generally harmful side effects. After introductory remarks on nitrogen as an air contaminant, the present potential in the derivation of emittor/receptor-relationships for nitrogen compounds are described. Subsequently, the nitrogen deposition rates are quantified and evaluated. (orig.)

  8. Atmospheric Plasma Deposition of Diamond-like Carbon Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Ladwig, Angela

    2008-01-23

    material that may be treated. The deposition of DLC at atmospheric pressure has been demonstrated by several researchers. Izake, et al [53] and Novikov and Dymont [54] have demonstrated an electrochemical process that is carried out with organic compounds such as methanol and acetylene dissolved in ammonia. This process requires that the substrates be immersed in the liquid [53-54]. The atmospheric pressure deposition of DLC was also demonstrated by Kulik, et al. utilizing a plasma torch. However, this process requires operating temperatures in excess of 800 oC [55]. In this report, we investigate the deposition of diamond-like carbon films using a low temperature, atmospheric pressure plasma-enhanced chemical vapor deposition (PECVD) process. The films were characterized by solid-state carbon-13 nuclear magnetic resonance (13C NMR) and found to have a ratio of sp2 to sp3 carbon of 43 to 57%. The films were also tested for adhesion, coefficient of friction, and dielectric strength.

  9. Chromium speciation in rainwater: temporal variability and atmospheric deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kieber, R.J.; Willey, J.D.; Zvalaren, S.D. [University of North Carolina at Wilmington, Wilmington, NC (United States). Dept. of Chemistry

    2002-12-15

    Chromium is released into the atmosphere by a variety of anthropogenic activities which include steel manufacturing, leather tanning, wood presentation and fossil fuel combustion. The concentrations of the various chromium species were determined in 89 rainwater samples collected in Wilmington, NC from October 1, 1999 to December 31, 2001. Volume weighted annual average concentrations of Cr{sub total}, particulate Cr, Cr(III)(aq), and Cr(VI)(aq) were 4.6, 2.2, 0.8 and 1.2 nM, respectively. There was distinct seasonal and diurnal variability in the concentrations of the various chromium species. Chromium emissions to the global atmosphere by both natural and anthropogenic sources are estimated to be 2.2 x 10{sup 9} mol/yr. Using rainwater concentration data along with other published rainwater Cr concentrations and an estimate for total global annual rain, the total global flux of chromium removed from the atmosphere via wet deposition is 2.1 x 10{sup 9} mol/yr. This represents complete removal of Cr and indicates that essentially all chromium released into the global atmosphere is removed via rain. About half this chromium is dissolved with roughly equal concentrations of toxic Cr(VI) and relatively harmless Cr(III) species. 48 refs., 4 figs., 3 tabs.

  10. Wet and dry deposition of atmospheric nitrogen at ten sites in Northern China

    OpenAIRE

    Y. P. Pan; Wang, Y.S.; Tang, G Q; Wu, D.

    2012-01-01

    Emissions of reactive nitrogen (N) species can affect surrounding ecosystems via atmospheric deposition. However, few long-term and multi-site measurements have focused on both the wet and the dry deposition of individual N species in large areas of Northern China. Thus, the magnitude of atmospheric deposition of various N species in Northern China remains uncertain. In this study, the wet and dry atmospheric deposition of different N species was investigated during a three-year observ...

  11. Meridional transport and deposition of atmospheric 10Be

    Directory of Open Access Journals (Sweden)

    J. Feichter

    2009-01-01

    Full Text Available 10Be concentrations measured in ice cores exhibit larger temporal variability than expected based on theoretical production calculations. To investigate whether this is due to atmospheric transport a general circulation model study is performed with the 10Be production divided into stratospheric, tropospheric tropical, tropospheric subtropical and tropospheric polar sources. A control run with present day 10Be production rate is compared with a run during a geomagnetic minimum. The present 10Be production rate is 4–5 times higher at high latitudes than in the tropics whereas during a period of no geomagnetic dipole field it is constant at all latitudes. The 10Be deposition fluxes, however, show a very similar latitudinal distribution in both the present day and the geomagnetic minimum run indicating that 10Be is well mixed in the atmosphere before its deposition. This is also confirmed by the fact that the contribution of 10Be produced in the stratosphere is dominant (55%–70% and relatively constant at all latitudes. The contribution of stratospheric 10Be is approximately 70% in Greenland and 60% in Antarctica reflecting the weaker stratosphere-troposphere air exchange in the Southern Hemisphere.

  12. Atmospheric lead deposition to Okefenokee Swamp, Georgia, USA

    Science.gov (United States)

    Jackson, B.P.; Winger, P.V.; Lasier, P.J.

    2004-01-01

    'Capsule:' Coal combustion emissions appear to be a major source of Pb in the Okefenokee wetland. Contamination of the environment from atmospheric deposition during the twentieth century is pervasive even in areas ostensibly considered pristine or remote from point sources. In this study, Pb concentrations in a Pb-210-dated peat core collected from the Okefenokee Swamp, GA were used to assess historical contaminant input via atmospheric deposition. Lead isotope ratios were determined by dynamic reaction cell ICP-MS (DRC-ICP-MS). Increases in Pb concentration occurred in the late nineteenth century and a marked rise in Pb concentrations pre-dated the widespread use of leaded gasoline within the US. The Pb-206/Pb-207 ratios of 1.19 during this period were consistent with coal combustion emissions. A later increase in Pb concentration, concurrent with a trend toward more radiogenic Pb-206/Pb-207 ratios in gasoline is consistent with an increased input of Pb from leaded gasoline emissions. However, it appears that coal combustion emissions remain a major source of Pb to the Okefenokee.

  13. XRF analysis of depth profiled thin depositions

    International Nuclear Information System (INIS)

    The main information about atmospheric and water pollutants is obtained from analysis of thin depositions on filters. Due its high sensitivity for a large number of elements, the XRF analysis based on X-ray tube as source of excitation, is a very advantageous method to measure samples of this kind. However, due to very large absorption photon cross sections in this energy range, the deposition profile can play an important role in analysis. Neglecting it might lead in some cases to wrong results. Assuming a normalized exponentially decaying profile as a realistic approximation of the deposition profile of a given element as ρ(x) = mkme-kmx/(1- e-kmD), where ρ(x) is element density at depth x, m - its surface density, km - deposition parameter and D - sample thickness, the yield, Y(km), of a characteristic X-line measured on a side of the sample is given as a function of Φ(E) - incident X-ray flux at energy E, σf(E) - photoelectric absorption cross section of the element, χ(E) - total X-ray absorption coefficient in sample considering both incidence and emergence path. Measuring the sample on the opposite side, the yield will be Y(-km), while from the ratio Y(-km)/Y(km) can be determined numerically. Since y(km) = Y(km)/m is independent of m, the deposition superficial mass is calculated using a thick standard as m = Y(s)S(x)/y(km)S(s), where S(x) (S(s)) is the X-line intensity measured in sample (standard) and theoretical yield in standard Y(s) is calculated using the formulas of Shiraiwa and Fujino. A computer code based on this formalism was written. Many samples of wet soil and aerosols deposition on filters, previously measured by other methods, were used to check the correctness of the present analysis procedure and a very good agreement is found between our results and the measurements taken as reference. A table is given with the results of the IAEA soil standard SOIL-7, deposited wet on a thin filter and measured after drying. The soil deposition was 3

  14. Atmospheric deposition of organochlorine contaminants to Galveston Bay, Texas

    Science.gov (United States)

    Park, June-Soo; Wade, Terry L.; Sweet, Stephen

    Atmospheric monitoring of PCBs and chlorinated pesticides (e.g., HCHs, chlordanes, and DDTs) in Galveston Bay was conducted at Seabrook, Texas. Air and wet deposition samples were collected from 2 February 1995 and continued through 6 August 1996. Vapor total PCB ( tPCB) concentrations in air ranged from 0.21 to 4.78 ng m -3 with a dominance of tri-chlorinated PCBs. Dissolved tPCBs in rain ranged from 0.08 to 3.34 ng l -1, with tetra-chlorinated PCBs predominating. The predominant isomers found in air and rain were α- and γ-HCH, α- and γ-chlordanes, 4,4'-DDT, and dieldrin. The concentrations of PCBs and pesticides in the air and rain revealed no clear seasonal trend. Elevated levels of PCBs in the air occurred when temperatures were high and wind came from urban and industrialized areas (S, SW, NW, and W of the site). Concentrations of HCHs were elevated in April, May, and October, perhaps due to local and/or regional applications of γ-HCH (lindane). Other pesticides showed no notable temporal variation. When winds originated from the Gulf of Mexico (southeasterly), lower concentrations of organochlorines were detected in the air. The direct deposition rate (wet+dry) of PCBs to Galveston Bay (6.40 μg m -2 yr -1) was significantly higher than that of pesticides by a factor of 5-10. The net flux from gas exchange estimated for PCBs was from Galveston Bay water to the atmosphere (78 μg m -2 yr -1). Gas exchange of PCBs from bay water to the atmosphere was the dominant flux.

  15. Assessment of dry and wet atmospheric deposits of radioactive aerosols: application to Fukushima radiocaesium fallout.

    Science.gov (United States)

    Gonze, Marc-André; Renaud, Philippe; Korsakissok, Irène; Kato, Hiroaki; Hinton, Thomas G; Mourlon, Christophe; Simon-Cornu, Marie

    2014-10-01

    The Fukushima Dai-ichi nuclear accident led to massive atmospheric deposition of radioactive substances onto the land surfaces. The spatial distribution of deposits has been estimated by Japanese authorities for gamma-emitting radionuclides through either airborne monitoring surveys (since April 2011) or in situ gamma-ray spectrometry of bare soil areas (since summer 2011). We demonstrate that significant differences exist between the two surveys for radiocaesium isotopes and that these differences can be related to dry deposits through the use of physically based relationships involving aerosol deposition velocities. The methodology, which has been applied to cesium-134 and cesium-137 deposits within 80-km of the nuclear site, provides reasonable spatial estimations of dry and wet deposits that are discussed and compared to atmospheric numerical simulations from the Japanese Atomic Energy Agency and the French Institute of Radioprotection and Nuclear Safety. As a complementary approach to numerical simulations, this field-based analysis has the possibility to contribute information that can be applied to the understanding and assessment of dose impacts to human populations and the environment around Fukushima. PMID:25196232

  16. Nitrogen concentrations in mosses indicate the spatial distribution of atmospheric nitrogen deposition in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Harmens, H., E-mail: hh@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Norris, D.A., E-mail: danor@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Cooper, D.M., E-mail: cooper@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Mills, G., E-mail: gmi@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Steinnes, E., E-mail: Eiliv.Steinnes@chem.ntnu.no [Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim (Norway); Kubin, E., E-mail: Eero.Kubin@metla.fi [Finnish Forest Research Institute, Kirkkosaarentie 7, 91500 Muhos (Finland); Thoeni, L., E-mail: lotti.thoeni@fub-ag.ch [FUB-Research Group for Environmental Monitoring, Alte Jonastrasse 83, 8640 Rapperswil (Switzerland); Aboal, J.R., E-mail: jesusramon.aboal@usc.es [University of Santiago de Compostela, Faculty of Biology, Department of Ecology, 15782 Santiago de Compostela (Spain); Alber, R., E-mail: Renate.Alber@provinz.bz.it [Environmental Agency of Bolzano, 39055 Laives (Italy); Carballeira, A., E-mail: alejo.carballeira@usc.es [University of Santiago de Compostela, Faculty of Biology, Department of Ecology, 15782 Santiago de Compostela (Spain); Coskun, M., E-mail: coskunafm@yahoo.com [Canakkale Onsekiz Mart University, Faculty of Medicine, Department of Medical Biology, 17100 Canakkale (Turkey); De Temmerman, L., E-mail: ludet@var.fgov.be [Veterinary and Agrochemical Research Centre, Tervuren (Belgium); Frolova, M., E-mail: marina.frolova@lvgma.gov.lv [Latvian Environment, Geology and Meteorology Agency, Riga (Latvia); Gonzalez-Miqueo, L., E-mail: lgonzale2@alumni.unav.es [Univ. of Navarra, Irunlarrea No 1, 31008 Pamplona (Spain)

    2011-10-15

    In 2005/6, nearly 3000 moss samples from (semi-)natural location across 16 European countries were collected for nitrogen analysis. The lowest total nitrogen concentrations in mosses (<0.8%) were observed in northern Finland and northern UK. The highest concentrations ({>=}1.6%) were found in parts of Belgium, France, Germany, Slovakia, Slovenia and Bulgaria. The asymptotic relationship between the nitrogen concentrations in mosses and EMEP modelled nitrogen deposition (averaged per 50 km x 50 km grid) across Europe showed less scatter when there were at least five moss sampling sites per grid. Factors potentially contributing to the scatter are discussed. In Switzerland, a strong (r{sup 2} = 0.91) linear relationship was found between the total nitrogen concentration in mosses and measured site-specific bulk nitrogen deposition rates. The total nitrogen concentrations in mosses complement deposition measurements, helping to identify areas in Europe at risk from high nitrogen deposition at a high spatial resolution. - Highlights: > Nitrogen concentrations in mosses were determined at ca. 3000 sites across Europe. > Moss concentrations were compared with EMEP modelled nitrogen deposition. > The asymptotic relationship for Europe showed saturation at ca. 15 kg N ha{sup -1} y{sup -1}. > Linear relationships were found with measured nitrogen deposition in some countries. > Moss concentrations complement deposition measurements at high spatial resolution. - Mosses as biomonitors of atmospheric nitrogen deposition in Europe.

  17. Atmospherically deposited trace metals from bulk mineral concentrate port operations

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Mark Patrick, E-mail: mark.taylor@mq.edu.au

    2015-05-15

    Although metal exposures in the environment have declined over the last two decades, certain activities and locations still present a risk of harm to human health. This study examines environmental dust metal and metalloid hazards (arsenic, cadmium, lead and nickel) associated with bulk mineral transport, loading and unloading port operations in public locations and children's playgrounds in the inner city of Townsville, northern Queensland. The mean increase in lead on post-play hand wipes (965 μg/m{sup 2}/day) across all sites was more than 10-times the mean pre-play loadings (95 μg/m{sup 2}/day). Maximum loading values after a 10-minute play period were 3012 μg/m{sup 2}, more than seven times the goal of 400 μg/m{sup 2} used by the Government of Western Australia (2011). Maximum daily nickel post-play hand loadings (404 μg/m{sup 2}) were more than 26 times above the German Federal Immission Control Act 2002 annual benchmark of 15 μg/m{sup 2}/day. Repeat sampling over the 5-day study period showed that hands and surfaces were re-contaminated daily from the deposition of metal-rich atmospheric dusts. Lead isotopic composition analysis of dust wipes ({sup 208}Pb/{sup 207}Pb and {sup 206}Pb/{sup 207}Pb) showed that surface dust lead was similar to Mount Isa type ores, which are exported through the Port of Townsville. While dust metal contaminant loadings are lower than other mining and smelting towns in Australia, they exceeded national and international benchmarks for environmental quality. The lessons from this study are clear — even where operations are considered acceptable by managing authorities, targeted assessment and monitoring can be used to evaluate whether current management practices are truly best practice. Reassessment can identify opportunities for improvement and maximum environmental and human health protection. - Graphical abstract: Post-play hand wipe, Headland Park, Townsville, Australia. - Highlights: • Bulk mineral port

  18. Estimated variability of National Atmospheric Deposition Program/Mercury Deposition Network measurements using collocated samplers

    Science.gov (United States)

    Wetherbee, G.A.; Gay, D.A.; Brunette, R.C.; Sweet, C.W.

    2007-01-01

    The National Atmospheric Deposition Program/Mercury Deposition Network (MDN) provides long-term, quality-assured records of mercury in wet deposition in the USA and Canada. Interpretation of spatial and temporal trends in the MDN data requires quantification of the variability of the MDN measurements. Variability is quantified for MDN data from collocated samplers at MDN sites in two states, one in Illinois and one in Washington. Median absolute differences in the collocated sampler data for total mercury concentration are approximately 11% of the median mercury concentration for all valid 1999-2004 MDN data. Median absolute differences are between 3.0% and 14% of the median MDN value for collector catch (sample volume) and between 6.0% and 15% of the median MDN value for mercury wet deposition. The overall measurement errors are sufficiently low to resolve between NADP/MDN measurements by ??2 ng??l-1 and ??2 ????m-2?? year-1, which are the contour intervals used to display the data on NADP isopleths maps for concentration and deposition, respectively. ?? Springer Science+Business Media B.V. 2007.

  19. PFPL, Puff Plume Atmospheric Radioactive or Toxic Deposition

    International Nuclear Information System (INIS)

    1 - Description of program or function: PFPL is an interactive transport and diffusion program developed for real-time calculation of the location and concentration of toxic or radioactive materials during an accidental release. Deposition calculations are included. The potential exists at the Savannah River Plant for releases of either toxic gases or radionuclides. The automated system developed to provide real-time information on the trajectory and concentration of an accidental release consists of meteorological towers, a minicomputer, and a network of terminals called the Weather Information and Display (WIND) System. PFPL which simulates either instantaneous (puff) or continuous (plume) releases is the primary code used at Savannah River for emergency response. In the PFPL model the diffusion process is separated into two phases. In phase I, the Gaussian cloud grows as a function of wind speed and stability class. Near the ground, the vertical concentration becomes logarithmic. Phase II begins when the vertical standard deviation reaches a value of 0.8 H, where H is the depth of the atmosphere's turbulent layer. At the horizontal distance from the source where the standard deviation = 0.8 H, the material remaining in the cloud is redistributed to a uniform vertical concentration throughout the mixed-layer. The logarithmic surface layer remains. The basic theory of the model assumes that the dry deposition rate is limited by surface deposition processes and by the rate at which turbulence can bring pollutants down to the surface (deposition) layer. The net effect of the two transfer rates determines the cloud depletion rate and surface concentrations. Depletion of the cloud by rain and radioactive decay is treated as an independent process. 2 - Method of solution: The fundamental equation solved is the general advection-diffusion equation, including gravitational settling, rainout, and radioactive decay

  20. Evaluation of atmospheric PCDD/F depositions via automated and traditional water surface samplers in Taiwan.

    Science.gov (United States)

    Chi, Kai Hsien; Kao, Shuh Ji; Liu, Kung Ting; Lee, Tzu Yi

    2012-03-01

    Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are a group of compounds of major environmental concern. Once emitted into the atmosphere, PCDD/Fs undergo photochemical reactions and enter other environmental compartments via wet and dry deposition. In this study, atmospheric PCDD/F depositions were collected via an automated PCDD/F deposition sampler and traditional cylindrical vessels, respectively, in northern, central, and southern Taiwan from 2008 to 2010. The automated PCDD/F precipitation sampler used in this study can prevent both resuspension and photodegradation of the PCDD/Fs collected and also effectively separates the PCDD/F samples into dry and wet contributions. The results indicate that the average atmospheric PCDD/F concentrations collected by the high-volume sampling trains were 13.6 ± 10 (n = 10), 15.6 ± 5.2 (n = 7), and 10.9 ± 6.3 (n = 6) fg I-TEQ/m(3) in northern, central, and southern Taiwan, respectively. In addition, the results also indicate that the PCDD/F deposition flux collected with an automated PCDD/F sampler (1.84 ± 0.90-8.68 ± 5.1 pg I-TEQ/m(2)/day, n = 23) is significantly higher than that sampled with cylindrical vessels (1.11 ± 0.69-5.64 ± 5.2 pg I-TEQ/m(2)/day, n = 23). Based on the Mann-Whitney statistical analysis, the p value (0.037) of PCDD/F deposition flux between those two samplers measurement is lower than 0.05. The difference is attributed to the fact that part of the PCDD/F depositions collected by traditional cylindrical vessels is photodegraded and revolatilized. In addition, the wet deposition flux of PCDD/Fs (3.66 to 470 pg I-TEQ/m(2)/rainy day, n = 23) observed in Taiwan is significantly higher than the dry deposition flux (0.38 to 4.55 pg I-TEQ/m(2)/sunny day, n = 23). The results demonstrate that the wet deposition is the major PCDD/F removal mechanism in the atmosphere. Furthermore, the overall PCDD/Fs deposition velocity and scavenging (rainout) coefficient in Taiwan are calculated as 0

  1. Modeling of Atmospheric Transport and Deposition of Heavy Metals in the Katowice Province

    OpenAIRE

    M. Uliasz; Olendrzynski, K.

    1996-01-01

    A large part of Poland's heavy industry, notably hard coal mining, ferrous and nonferrous metallurgy and power generation, is located in the Katowice province. Therefore, this heavy industrialized region, which is populated by four million people, experiences considerable problems with air pollution. In the METKAT study launched by the International Institute for Applied Systems Analysis we attempt to model atmospheric depositions of arsenic (As), cadmium (Cd), lead (Pb) and zinc (Zn) which a...

  2. LEAF WASHING AS AN ASSESSMENT TOOL TO CHARACTERIZE DRY ATMOSPHERIC DEPOSITION

    OpenAIRE

    Livia Vittori Antisari; Serena Carbone; Chiara Ferronato; Andrea Simoni; Gilmo Vianello

    2012-01-01

    The aim of this work was to characterize dry atmospheric deposition after the washing of broad leaves and conifer foliage. To assess this method different sites chosen on the basis of different exposure to both point (e.g. waste incinerator plant (WIP), local crafts) and widespread (e.g. roads, agricultural practices) sources of anthropogenic pollution.The principal components analysis (PCA), performed on the major and trace elements identified after leaf washing, extracted four factors. F2 w...

  3. Atmospheric wet deposition of sulfur and nitrogen in Jiuzhaigou National Nature Reserve, Sichuan Province, China.

    Science.gov (United States)

    Qiao, Xue; Xiao, Weiyang; Jaffe, Daniel; Kota, Sri Harsha; Ying, Qi; Tang, Ya

    2015-04-01

    In the last two decades, remarkable ecological changes have been observed in Jiuzhaigou National Nature Reserve (JNNR). Some of these changes might be related to excessive deposition of sulfur (S) and nitrogen (N), but the relationship has not been quantified due to lack of monitoring data, particularly S and N deposition data. In this study, we investigated the concentrations, fluxes, and sources of S and N wet deposition in JNNR from April 2010 to May 2011. The results show that SO4(2-), NO3-, and NH4+ concentrations in the wet deposition were 39.4-170.5, 6.2-34.8, and 0.2-61.2 μeq L(-1), with annual Volume-Weighted Mean (VWM) concentrations of 70.5, 12.7, and 13.4 μeq L(-1), respectively. Annual wet deposition fluxes of SO4(2-), NO3-, and NH4+ were 8.06, 1.29, and 1.39 kg S(N)ha(-1), respectively, accounting for about 90% of annual atmospheric inputs of these species at the monitoring site. The results of Positive Matrix Factorization (PMF) analysis show that fossil fuel combustion, agriculture, and aged sea salt contributed to 99% and 83% of annual wet deposition fluxes of SO4(2-) and NO3-, respectively. Agriculture alone contributed to 89% of annual wet deposition flux of NH4+. Although wet deposition in JNNR was polluted by anthropogenic acids, the acidity was largely neutralized by the Ca2+ from crust and 81% of wet deposition samples had a pH higher than 6.00. However, acid rain mainly caused by SO4(2-) continued to occur in the wet season, when ambient alkaline dust concentration was lower. Since anthropogenic emissions have elevated S and N deposition and caused acid rain in JNNR, further studies are needed to better quantify the regional sources and ecological effects of S and N deposition for JNNR.

  4. Assessing the atmospheric deposition of mercury to Lake Michigan: The importance of the Chicago/Gary urban area on wet and dry deposition

    Science.gov (United States)

    Landis, Matthew Scott

    1998-12-01

    Mercury is a toxic bioaccumulative substance found in aquatic ecosystems. The results of the first study of atmospheric mercury deposition into Lake Michigan and the relative importance of the Chicago/Gary urban area were investigated as part of the Lake Michigan Mass Balance Study (LMMBS) and the Atmospheric Exchange Over Lakes and Oceans Study (AEOLOS). Event wet-only precipitation, total aerosol, and vapor phase samples were collected for mercury and trace element determinations from five sites around Lake Michigan from July 1994 through October 1995 as part of the LMMBS. In addition, intensive over-water measurements were conducted aboard the EPA research vessel Lake Guardian during the summer of 1994 and the winter of 1995 as part of the AEOLOS. Atmospheric mercury concentrations were from two to ten times higher in the Chicago/Gary urban area. Wet and dry Hg deposition (including reactive gaseous Hg) were calculated to Lake Michigan using a hybrid receptor modeling framework. The model utilized mercury monitoring data collected during the LMMBS and AEOLOS together with high resolution over-water meteorological data provided by the National Oceanic and Atmospheric Administration. Atmospheric deposition was found to be the primary pathway for mercury input to Lake Michigan, contributing approximately 84% of the estimated 1419 Kg annual flux. Wet deposition (10.6 μg m-2) and dry deposition (10.0 μg m-2) contributed almost equally to the annual atmospheric Hg deposition of 20.6 μg m-2 (1189 Kg). A strong urban influence was observed in the over-water mercury deposition estimates in the southern portion of the lake. An independent meteorological transport analysis determined that local sources in the Chicago/Gary urban area significantly impacted the LMMBS sites around Lake Michigan. The Chicago/Gary urban area was found to contribute about 20% (127 Kg) of the annual atmospheric mercury deposition to Lake Michigan. Multivariate statistical analysis of

  5. Decreased atmospheric sulfur deposition across the southeastern U.S.: when will watersheds release stored sulfate?

    Science.gov (United States)

    Rice, Karen C.; Scanlon, Todd S.; Lynch, Jason A.; Cosby, Bernard J.

    2014-01-01

    Emissions of sulfur dioxide (SO2) to the atmosphere lead to atmospheric deposition of sulfate (SO42-), which is the dominant strong acid anion causing acidification of surface waters and soils in the eastern United States (U.S.). Since passage of the Clean Air Act and its Amendments, atmospheric deposition of SO2 in this region has declined by over 80%, but few corresponding decreases in stream-water SO42- concentrations have been observed in unglaciated watersheds. We calculated SO42- mass balances for 27 forested, unglaciated watersheds from Pennsylvania to Georgia, by using total atmospheric deposition (wet plus dry) as input. Many of these watersheds still retain SO42-, unlike their counterparts in the northeastern U.S. and southern Canada. Our analysis showed that many of these watersheds should convert from retaining to releasing SO42- over the next two decades. The specific years when the watersheds crossover from retaining to releasing SO42- correspond to a general geographical pattern of later net watershed release from north to south. The single most important variable that explained the crossover year was the runoff ratio, defined as the ratio of annual mean stream discharge to precipitation. Percent clay content and mean soil depth were secondary factors in predicting crossover year. The conversion of watersheds from net SO42- retention to release anticipates more widespread reductions in stream-water SO42- concentrations in this region.

  6. Atmospheric wet and dry deposition of trace elements at 10 sites in Northern China

    OpenAIRE

    Pan, Y. P.; Y. S. Wang

    2015-01-01

    Atmospheric deposition is considered to be a major process that removes pollutants from the atmosphere and an important source of nutrients and contaminants for ecosystems. Trace elements (TEs), especially toxic metals deposited on plants and into soil or water, can cause substantial damage to the environment and human health due to their transfer and accumulation in food chains. Despite public concerns, quantitative knowledge of metal deposition from the atmosphere to ecosy...

  7. Impact of biomass burning on ocean water quality in Southeast Asia through atmospheric deposition: eutrophication modeling

    OpenAIRE

    P. Sundarambal; P. Tkalich; Balasubramanian, R

    2010-01-01

    Atmospheric deposition of nutrients (N and P species) can intensify anthropogenic eutrophication of coastal waters. It was found that the atmospheric wet and dry depositions of nutrients was remarkable in the Southeast Asian region during the course of smoke haze events, as discussed in a companion paper on field observations (Sundarambal et al., 2010b). The importance of atmospheric deposition of nutrients in terms of their biological responses in the coastal waters of the ...

  8. Atmospheric nitrogen deposition to the northwestern Pacific: seasonal variation and source attribution

    Science.gov (United States)

    Zhao, Yuanhong; Zhang, Lin; Pan, Yuepeng; Wang, Yuesi; Paulot, Fabien; Henze, Daven

    2016-04-01

    Rapid Asian industrialization has lead to increased atmospheric nitrogen deposition downwind threatening the marine environment. We present an analysis of the sources and processes controlling atmospheric nitrogen deposition to the northwestern Pacific, using the GEOS-Chem global chemistry model and its adjoint model at 1/2°× 2/3° horizontal resolution over the East Asia and its adjacent oceans. We focus our analyses on the marginal seas: the Yellow Sea and the South China Sea. Asian nitrogen emissions in the model are 28.6 Tg N a-1 as NH3 and 15.7 Tg N a-1 as NOx. China has the largest sources with 12.8 Tg N a-1 as NH3 and 7.9 Tg N a-1 as NOx; the much higher NH3 emissions reflect its intensive agricultural activities. We improve the seasonality of Asian NH3 emissions; emissions are a factor of 3 higher in summer than winter. The model simulation for 2008-2010 is evaluated with NH3 and NO2 column observations from satellite instruments, and wet deposition flux measurements from surface monitoring sites. Simulated atmospheric nitrogen deposition to the northwestern Pacific ranges 0.8-20 kg N ha-1 a-1, decreasing rapidly downwind the Asian continent. Deposition fluxes average 11.9 kg N ha-1 a-1 (5.0 as reduced nitrogen NHx and 6.9 as oxidized nitrogen NOy) to the Yellow Sea, and 5.6 kg N ha-1 a-1 (2.5 as NHx and 3.1 as NOy) to the South China Sea. Nitrogen sources over the ocean (ship NOx and oceanic NH3) have little contribution to deposition over the Yellow Sea, about 7% over the South China Sea, and become important (greater than 30%) further downwind. We find that the seasonality of nitrogen deposition to the northwestern Pacific is determined by variations in meteorology largely controlled by the East Asian Monsoon and in nitrogen emissions. The model adjoint further points out that nitrogen deposition to the Yellow Sea originates from sources over China (92% contribution) and the Korean peninsula (7%), and by sectors from fertilizer use (24%), power plants

  9. Role of volcanic dust in the atmospheric transport and deposition of polycyclic aromatic hydrocarbons and mercury.

    Science.gov (United States)

    Stracquadanio, Milena; Dinelli, Enrico; Trombini, Claudio

    2003-12-01

    The role of volcanic ash as scavenger of atmospheric pollutants, in their transport and final deposition to the ground is examined. Attention is focused on polycyclic aromatic hydrocarbons (PAHs) and on particulate mercury (Hgp). The ash-fall deposits studied belong to the 2001 and 2002 eruptive activity of Mount Etna, Southern Italy, and were investigated at three (2001) and four (2002) sites downwind of the major tephra dispersal pattern. The dry deposition of mercury and PAHs was determined, and, in particular, a downward flux to the ground of PAHs (approximately 7.29 microg m(-2) per day) and mercury (750 ng m(-2) per day) was estimated in Catania from October 26 to October 28, 2002. Finally, evidence on the anthropogenic origin of PAHs scavenged from the troposphere by volcanic ash is supported by the analysis of PAH compositions in granulometrically homogeneous fractions.

  10. Structural properties of zinc oxide deposited using atmospheric pressure combustion chemical vapour deposition

    International Nuclear Information System (INIS)

    In this study the deposition of thin zinc oxide (ZnO) films under atmospheric pressure conditions was investigated. The deposition technique applied was combustion chemical vapour deposition (CCVD), at which a propane–air mixture was combusted in a burner. Dissolved zinc nitrate was used as precursor, which was guided as aerosol droplets by the processing gas flow directly into the reaction zone. Fundamental investigations were performed to form undoped ZnO. The structural properties of the films were analysed in dependence of the substrate temperature during the coating process. The presence of crystalline ZnO structures was proved and differences in film growth and crystallite sizes are revealed. Additionally, the particles generated by the CCVD-flame are characterised. The thin films showed a slight excess of Zn and several states of binding energy could be observed by fitting the core level spectra. Scanning and transmission electron microscopy also indicated ordered structures and additionally different orientations of crystallites were observed. - Highlights: • Columnar growth structures of ZnO by CCVD were observed. • The presence of polycrystalline ZnO with (002) as main orientation was confirmed. • Initial particles significantly differ from crystallite sizes of the resulting films. • The films show an excess of Zn with a Zn-to-O ratio of around 1.7

  11. Structural properties of zinc oxide deposited using atmospheric pressure combustion chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zunke, I., E-mail: iz@innovent-jena.de [Innovent e.V. Technology Development, Department of Surface Engineering, Prüssingstr. 27B, 07745 Jena (Germany); Wolf, S. [University of Jena, Institute for Solid State Physics, Helmholtzweg 3/5, 07745 Jena (Germany); Heft, A.; Schimanski, A.; Grünler, B. [Innovent e.V. Technology Development, Department of Surface Engineering, Prüssingstr. 27B, 07745 Jena (Germany); Ronning, C.; Seidel, P. [University of Jena, Institute for Solid State Physics, Helmholtzweg 3/5, 07745 Jena (Germany)

    2014-08-28

    In this study the deposition of thin zinc oxide (ZnO) films under atmospheric pressure conditions was investigated. The deposition technique applied was combustion chemical vapour deposition (CCVD), at which a propane–air mixture was combusted in a burner. Dissolved zinc nitrate was used as precursor, which was guided as aerosol droplets by the processing gas flow directly into the reaction zone. Fundamental investigations were performed to form undoped ZnO. The structural properties of the films were analysed in dependence of the substrate temperature during the coating process. The presence of crystalline ZnO structures was proved and differences in film growth and crystallite sizes are revealed. Additionally, the particles generated by the CCVD-flame are characterised. The thin films showed a slight excess of Zn and several states of binding energy could be observed by fitting the core level spectra. Scanning and transmission electron microscopy also indicated ordered structures and additionally different orientations of crystallites were observed. - Highlights: • Columnar growth structures of ZnO by CCVD were observed. • The presence of polycrystalline ZnO with (002) as main orientation was confirmed. • Initial particles significantly differ from crystallite sizes of the resulting films. • The films show an excess of Zn with a Zn-to-O ratio of around 1.7.

  12. Sources, transport and deposition of iron in the global atmosphere

    Science.gov (United States)

    Wang, R.; Balkanski, Y.; Boucher, O.; Bopp, L.; Chappell, A.; Ciais, P.; Hauglustaine, D.; Peñuelas, J.; Tao, S.

    2015-06-01

    Atmospheric deposition of iron (Fe) plays an important role in controlling oceanic primary productivity. However, the sources of Fe in the atmosphere are not well understood. In particular, the combustion sources of Fe and the subsequent deposition to the oceans have been accounted for in only few ocean biogeochemical models of the carbon cycle. Here we used a mass-balance method to estimate the emissions of Fe from the combustion of fossil fuels and biomass by accounting for the Fe contents in fuel and the partitioning of Fe during combustion. The emissions of Fe attached to aerosols from combustion sources were estimated by particle size, and their uncertainties were quantified by a Monte Carlo simulation. The emissions of Fe from mineral sources were estimated using the latest soil mineralogical database to date. As a result, the total Fe emissions from combustion averaged for 1960-2007 were estimated to be 5.3 Tg yr-1 (90% confidence of 2.3 to 12.1). Of these emissions, 1, 27 and 72% were emitted in particles 10 μm (PM> 10), respectively, compared to a total Fe emission from mineral dust of 41.0 Tg yr-1 in a log-normal distribution with a mass median diameter of 2.5 μm and a geometric standard deviation of 2. For combustion sources, different temporal trends were found in fine and medium-to-coarse particles, with a notable increase in Fe emissions in PM1 since 2000 due to an increase in Fe emission from motor vehicles (from 0.008 to 0.0103 Tg yr-1 in 2000 and 2007, respectively). These emissions have been introduced in a global 3-D transport model run at a spatial resolution of 0.94° latitude by 1.28° longitude to evaluate our estimation of Fe emissions. The modelled Fe concentrations as monthly means were compared with the monthly (57 sites) or daily (768 sites) measured concentrations at a total of 825 sampling stations. The deviation between modelled and observed Fe concentrations attached to aerosols at the surface was within a factor of 2 at most

  13. Sources, transport and deposition of iron in the global atmosphere

    Directory of Open Access Journals (Sweden)

    R. Wang

    2015-03-01

    Full Text Available Atmospheric deposition of iron (Fe plays an important role in controlling oceanic primary productivity. However, the sources of Fe in the atmosphere are not well understood. In particular, the combustion sources of Fe and their deposition over oceans are not accounted for in current biogeochemical models of the carbon cycle. Here we used a mass-balance method to estimate the emissions of Fe from the combustion of fossil fuels and biomass by accounting for the Fe contents in fuel and the partitioning of Fe during combustion. The emissions of Fe attached to aerosols from combustion sources were estimated by particle size, and their uncertainties were quantified by a Monte Carlo simulation. The emissions of Fe from mineral sources were estimated using the latest soil mineralogical database to date. As a result, the total Fe emissions from combustion averaged for 1960–2007 were estimated to be 5.1 Tg yr−1 (90% confidence of 2.2 to 11.5. Of these emissions, 2, 33 and 65% were emitted in particles 1, 1–10 μm (PM1−10, and >10 μm (PM>10, respectively, compared to total Fe emissions from mineral sources of 41.0 Tg yr−1. For combustion sources, different temporal trends were found in fine and medium-to-coarse particles, with a notable increase in Fe emissions in PM1 and PM1−10 since 2000 due to a rapid increase from motor vehicles. These emissions have been introduced in a global 3-D transport model run at a spatial resolution of of 0.94° latitude by 1.28° longitude to evaluate our estimation of Fe emissions. The modelled Fe concentrations were compared to measurements at 825 sampling stations. The deviation between modelled and observed Fe concentrations attached to aerosols at the surface was within a factor of two at most sampling stations, and the deviation was within a factor of 1.5 at sampling stations dominated by combustion sources. We analyzed the relative contribution of combustion sources to total Fe concentrations over

  14. Atmospheric Deposition of Heavy Metals around the Lead and Copper-Zinc Smelters in Baia Mare, Romania, Studied by the Moss Biomonitoring Technique, Neutron Activation Analysis and Flame Atomic Absorption Spectrometry

    CERN Document Server

    Culicov, O A; Steinnes, E; Okina, O S; Santa, Z; Todoran, R

    2002-01-01

    The mosses Pleurozium schreberi, Pseudoscleropodium purum and Rhytidiadelphus squarrosus were used as biomonitors to study the atmospheric deposition of heavy metals around the lead and copper-zinc smelters in Baia Mare. Samples representing the last three years' growth of moss or its green part, collected on the ground at 28 sites located 2-17 km from the source area, were analyzed by instrumental neutron activation analysis using epithermal neutrons and by flame atomic absorption spectrometry. A total of 31 elements were determined, including most of the heavy metals characteristic of emissions from this kind industry. The observed data for Pb, As, Cu, and Cd are all high compared with those observed in other regions of Europe with similar industries, but the concentrations in moss approach regional background levels at a distance of about 8 km from the main source area. Factor analysis of the data distinguishes two industrial components, one characterized by Pb, Cu, As, and Sb, and another one by Zn and Cd...

  15. Influence of atmospheric deposition on Okefenokee National Wildlife Refuge

    Science.gov (United States)

    Winger, P.V.; Lasier, P.J.; Jackson, B.P.

    1995-01-01

    Designation of Okefenokee National Wildlife Refuge (Georgia) as a Class I Air Quality Area affords mandatory protection of the airshed through permit-review processes for planned developments. Rainfall is the major source of water to the swamp, and potential impacts from developments in the airshed are high. To meet management needs for baseline information, chemical contributions from atmospheric deposition and partitioning of anions and cations in various matrices of the swamp, with emphasis on mercury and lead, were determined during this study. Chemistry of rainfall was measured on an event basis from one site and quarterly on surface water, pore water, floc, and sediment from four locations. A sediment core collected from the Refuge interior was sectioned, aged, and analyzed for mercury. Rainfall was acidic (pH 4.7-4.9), with average total and methyl mercury concentrations of 9 ng/L and 0.1 ng/L, respectively. Surface waters were acidic (pH 3.8-4.1), dilute (specific conductance 35-60 pS), and highly organic (dissolved organic carbon 35-50 mg/L). Total mercury was 1-3.5 ng/L in surface and pore water, and methyl mercury was 0.02-0.20 ng/L. Total mercury in sediments and floc was 100-200 ng/g dry weight, and methyl mercury was 4-16 ng/g. Lead was 0-1.7 pg/L in rainfall, not detectable in surface water, 3.4-5.4 pg/L in pore water, and 3.9-4.9 mg/kg in floc and sediment. Historical patterns of mercury deposition showed an increase in total mercury from pre-1800 concentrations of 250 ng/g to 500 ng/g in 1950, with concentrations declining thereafter to present.

  16. Crediting Tritium Deposition in Accident Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, C.E. Jr.

    2001-06-20

    This paper describes the major aspects of tritium dispersion phenomenology, summarizes deposition attributes of the computer models used in the DOE Complex for tritium dispersion, and recommends an approach to account for deposition in accident analysis.

  17. Imbalanced atmospheric nitrogen and phosphorus depositions in China: Implications for nutrient limitation

    Science.gov (United States)

    Zhu, Jianxing; Wang, Qiufeng; He, Nianpeng; Smith, Melinda D.; Elser, James J.; Du, Jiaqiang; Yuan, Guofu; Yu, Guirui; Yu, Qiang

    2016-06-01

    Atmospheric wet nitrogen (N) and phosphorus (P) depositions are important sources of bioavailable N and P, and the input of N and P and their ratios significantly influences nutrient availability and balance in terrestrial as well as aquatic ecosystems. Here we monitored atmospheric P depositions by measuring monthly dissolved P concentration in rainfall at 41 field stations in China. Average deposition fluxes of N and P were 13.69 ± 8.69 kg N ha-1 a-1 (our previous study) and 0.21 ± 0.17 kg P ha-1 a-1, respectively. Central and southern China had higher N and P deposition rates than northwest China, northeast China, Inner Mongolia, or Qinghai-Tibet. Atmospheric N and P depositions showed strong seasonal patterns and were dependent upon seasonal precipitation. Fertilizer and energy consumption were significantly correlated with N deposition but less correlated with P deposition. The N:P ratios of atmospheric wet deposition (with the average of 77 ± 40, by mass) were negatively correlated with current soil N:P ratios in different ecological regions, suggesting that the imbalanced atmospheric N and P deposition will alter nutrient availability and strengthen P limitation, which may further influence the structure and function of terrestrial ecosystems. The findings provide the assessments of both wet N and P deposition and their N:P ratio across China and indicate potential for strong impacts of atmospheric deposition on broad range of terrestrial ecosystems.

  18. The investigation of atmospheric deposition distribution of organochlorine pesticides (OCPs) in Turkey

    Science.gov (United States)

    Cindoruk, S. Sıddık; Tasdemir, Yücel

    2014-04-01

    Atmospheric deposition is a significant pollution source leading to contamination of remote and clean sites, surface waters and soils. Since persistent organic pollutants (POPs) stay in atmosphere without any degradation, they can be transported and deposited to clean surfaces. Organochlorine pesticides are an important group of POPs which have toxic and harmful effects to living organisms and environment. Therefore, atmospheric deposition levels and characteristics are of importance to determine the pollution quantity of water and soil surfaces in terms of POPs. This study reports the distribution quantities of atmospheric deposition including bulk, dry, wet and air-water exchange of particle and gas phase OCPs as a result of 1-year sampling campaign. Atmospheric deposition distribution showed that the main mechanism for OCPs deposition is wet processes with percentage of 69 of total deposition. OCP compounds' deposition varied according to atmospheric concentration and deposition mechanism. HCH compounds were dominant pesticide species for all deposition mechanisms. HCH deposition constituted the 65% of Σ10OCPs.

  19. Modeling and mapping of atmospheric mercury deposition in adirondack park, new york.

    Directory of Open Access Journals (Sweden)

    Xue Yu

    Full Text Available The Adirondacks of New York State, USA is a region that is sensitive to atmospheric mercury (Hg deposition. In this study, we estimated atmospheric Hg deposition to the Adirondacks using a new scheme that combined numerical modeling and limited experimental data. The majority of the land cover in the Adirondacks is forested with 47% of the total area deciduous, 20% coniferous and 10% mixed. We used litterfall plus throughfall deposition as the total atmospheric Hg deposition to coniferous and deciduous forests during the leaf-on period, and wet Hg deposition plus modeled atmospheric dry Hg deposition as the total Hg deposition to the deciduous forest during the leaf-off period and for the non-forested areas year-around. To estimate atmospheric dry Hg deposition we used the Big Leaf model. The average atmospheric Hg deposition to the Adirondacks was estimated as 17.4 [Formula: see text]g m[Formula: see text] yr[Formula: see text] with a range of -3.7-46.0 [Formula: see text]g m[Formula: see text] yr[Formula: see text]. Atmospheric Hg dry deposition (370 kg yr[Formula: see text] was found to be more important than wet deposition (210 kg yr[Formula: see text] to the entire Adirondacks (2.4 million ha. The spatial pattern showed a large variation in atmospheric Hg deposition with scattered areas in the eastern Adirondacks having total Hg deposition greater than 30 μg m(-2 yr(-1, while the southwestern and the northern areas received Hg deposition ranging from 25-30 μg m(-2 yr(-1.

  20. Model-Based Analysis of the Effect of Long-term Atmospheric Nitrogen Deposition on Nitrogen and Carbon Dynamics in Northern Peatlands

    Science.gov (United States)

    Wu, Y.; Blodau, C.

    2011-12-01

    Peatlands as a unique biological community that provide important ecological, economic and protective functions are highly threatened by climate change and nitrogen deposition. A process based model has been developed to simulate short term and long term changes in peatlands biogeochemistry and ecology. The model contains three modules: Hydrothermal generates daily water table and soil temperature as environmental inputs for other modules; Plant dynamics simulates the competition of plants in natural nutrient poor condition and the potential shifting of ecosystem under high nutrient input and climate change; Soil organic matter (SOM) dynamics simulates the decomposition of SOM into mineralized carbon and nitrogen and their transformation and translocation within the peat and efflux. This model especially focuses on nitrogen dynamics both in plant and soil and the coupling of nitrogen cycle to carbon cycle for peatland. Water table is modeled as a bucket model that calculates real time water storage from precipitation, evapotranspiration and runoff, which in turn generates water table level and soil moisture profile in soil. Soil temperature along depth is calculated from soil thermal conductivity features and air temperature. Plant carbon and nitrogen dynamics are modeled for 3 plant functional types (moss, graminoids and shrubs) with different tolerant levels to temperate, moisture, light and nutrients. SOM decomposition is simulated in a layer structure with 5cm resolution. Within each layer one labile and one recalcitrant organic carbon and nitrogen pool are decomposed simultaneously on rates controlled by SOM quality, nitrogen availability and environment. Simulation for water table, Temperature, plant dynamics, carbon nitrogen budget and fluxes and peat initiation for Mer Bleue bog (Ottawa Canada, Fluxnet data) shows good correlation with field data. SOM decomposition simulation reveals that the extremely low decomposition rate of SOM in saturated zone plays

  1. Atmospheric nitrogen deposition in world biodiversity hotspots: the need for a greater global perspective in assessing N deposition impacts

    NARCIS (Netherlands)

    Phoenix, G.K.; Hicks, W.K.; Cinderby, S.; Kuylenstierna, J.C.I.; Stock, W.D.; Dentener, F.J.; Giller, K.E.; Austin, A.T.; Lefroy, R.D.B.; Gimeno, B.S.; Ashmore, M.R.; Ineson, P.

    2006-01-01

    Increased atmospheric nitrogen (N) deposition is known to reduce plant diversity in natural and semi-natural ecosystems, yet our understanding of these impacts comes almost entirely from studies in northern Europe and North America. Currently, we lack an understanding of the threat of N deposition t

  2. Recent atmospheric dust deposition in an ombrotrophic peat bog from the Himalaya

    International Nuclear Information System (INIS)

    Ombrotrophic peat bogs, are important natural archives for records of atmospheric pollution by heavy metals. As continental geochemical archives in exclusively recording past atmospheric deposition, they have the unique advantage of a wide global distribution relative to ice cores. Mean annual depositional fluxes of these elements across the peat bog surface are mainly controlled by the atmospheric concentration and total rainfall. To characterize historical trends in the extent and sources of environmental pollution, a peat core from the Pinder Valley (30.05°N, 79.93°E) in the Himalaya was collected. 210Pb and 137Cs radionuclides, with well-define fallout records are used for dating the past 150 years of peat accumulation. Beyond this, 14C AMS dating was used for dating the core. The activities of radionuclides were measured using High Purity Germanium Gamma detector and the concentrations of refractory lithogenic (AI, Ca, Fe, Mn, V and Ti) and trace elements (Pb, Cu, Zn, Co, Ni, Mo, Cr, Sr and Ba) using ICP-MS. In this study, the historical records obtained from the peat bog from the Himalaya extending up to 5000 years show evidence for rising anthropogenic inputs of trace metals to the remote high altitude atmosphere since 1970s, resulting largely from fossil fuel consumption, non-ferrous metal production, coal-powered electricity generation and fertilizer use. Geochemistry of peat and the analysis of past environmental changes will be presented. (author)

  3. Modeling the global atmospheric transport and deposition of mercury to the Great Lakes

    NARCIS (Netherlands)

    Cohen, Mark D.; Draxler, Roland R.; Artz, Richard S.; Blanchard, Pierrette; Gustin, Mae Sexauer; Han, Young Ji; Holsen, Thomas M.; Jaffe, Daniel A.; Kelley, Paul; Lei, Hang; Loughner, Christopher P.; Luke, Winston T.; Lyman, Seth N.; Niemi, David; Pacyna, Jozef M.; Pilote, Martin; Poissant, Laurier; Ratte, Dominique; Ren, Xinrong; Steenhuisen, Frits; Steffen, Alexandra; Tordon, Rob; Wilson, Simon J.

    2016-01-01

    Mercury contamination in the Great Lakes continues to have important public health and wildlife ecotoxicology impacts, and atmospheric deposition is a significant ongoing loading pathway. The objective of this study was to estimate the amount and source-attribution for atmospheric mercury deposition

  4. Methodology and Significance of Studies of Atmospheric Deposition in Highway Runoff

    Science.gov (United States)

    Colman, John A.; Rice, Karen C.; Willoughby, Timothy C.

    2001-01-01

    Atmospheric deposition and the processes that are involved in causing and altering atmospheric deposition in relation to highway surfaces and runoff were evaluated nationwide. Wet deposition is more easily monitored than dry deposition, and data on wet deposition are available for major elements and water properties (constituents affecting acid deposition) from the inter-agency National Atmospheric Deposition Program/ National Trends Network (NADP/NTN). Many trace constituents (metals and organic compounds) of interest in highway runoff loads, however, are not included in the NADP/NTN. Dry deposition, which constitutes a large part of total atmospheric deposition for many constituents in highway runoff loads, is difficult to monitor accurately. Dry-deposition rates are not widely available. Many of the highway-runoff investigations that have addressed atmospheric-deposition sources have had flawed investigative designs or problems with methodology. Some results may be incorrect because of reliance on time-aggregated data collected during a period of changing atmospheric emissions. None of the investigations used methods that could accurately quantify the part of highway runoff load that can be attributed to ambient atmospheric deposition. Lack of information about accurate ambient deposition rates and runoff loads was part of the problem. Samples collected to compute the rates and loads were collected without clean-sampling methods or sampler protocols, and without quality-assurance procedures that could validate the data. Massbudget calculations comparing deposition and runoff did not consider loss of deposited material during on-highway processing. Loss of deposited particles from highway travel lanes could be large, as has been determined in labeled particle studies, because of resuspension caused by turbulence from passing traffic. Although a cause of resuspension of large particles, traffic turbulence may increase the rate of deposition for small particles and

  5. Aerosol assisted atmospheric pressure chemical vapor deposition of silicon thin films using liquid cyclic hydrosilanes

    International Nuclear Information System (INIS)

    Silicon (Si) thin films were produced using an aerosol assisted atmospheric pressure chemical vapor deposition technique with liquid hydrosilane precursors cyclopentasilane (CPS, Si5H10) and cyclohexasilane (CHS, Si6H12). Thin films were deposited at temperatures between 300 and 500 °C, with maximum observed deposition rates of 55 and 47 nm/s for CPS and CHS, respectively, at 500 °C. Atomic force microscopic analyses of the films depict smooth surfaces with roughness of 4–8 nm. Raman spectroscopic analysis indicates that the Si films deposited at 300 °C and 350 °C consist of a hydrogenated amorphous Si (a-Si:H) phase while the films deposited at 400, 450, and 500 °C are comprised predominantly of a hydrogenated nanocrystalline Si (nc-Si:H) phase. The wide optical bandgaps of 2–2.28 eV for films deposited at 350–400 °C and 1.7–1.8 eV for those deposited at 450–500 °C support the Raman data and depict a transition from a-Si:H to nc-Si:H. Films deposited at 450 oC possess the highest photosensitivity of 102–103 under AM 1.5G illumination. Based on the growth model developed for other silanes, we suggest a mechanism that governs the film growth using CPS and CHS. - Highlights: • Si films via AA-APCVD are realized using cyclopentasilane (CPS) and cyclohexasilane (CHS). • Low activation energies of CPS and CHS allow Si thin films at low temperatures (300 °C). • High growth rates of 47–55 nm/s were obtained at 500 °C • Near device quality Si thin films with 2–3 orders of photosensitivity • Si thin films via AA-APCVD are amenable to continuous roll-to-roll manufacturing

  6. Mead: An interdisciplinary study of the marine effects of atmospheric deposition in the Kattegat

    Energy Technology Data Exchange (ETDEWEB)

    Spokes, L. [School of Environmental Sciences, University of East Anglia, East Anglia (United Kingdom); Jickells, T. [School of Environmental Sciences, University of East Anglia, East Anglia (United Kingdom)]. E-mail: t.jickells@uea.ac.uk; Weston, K. [School of Environmental Sciences, University of East Anglia, East Anglia (United Kingdom); Gustafsson, B.G. [Department of Oceanography, Goteborg University, Goteborg (Sweden); Johnsson, M. [Department of Oceanography, Goteborg University, Goteborg (Sweden); Liljebladh, B. [Department of Oceanography, Goteborg University, Goteborg (Sweden); Conley, D. [National Environmental Research Institute, Roskilde (Denmark); Ambelas-Skjodth, C. [National Environmental Research Institute, Roskilde (Denmark); Brandt, J. [National Environmental Research Institute, Roskilde (Denmark); Carstensen, J. [National Environmental Research Institute, Roskilde (Denmark); Christiansen, T. [National Environmental Research Institute, Roskilde (Denmark); Frohn, L. [National Environmental Research Institute, Roskilde (Denmark); Geernaert, G. [National Environmental Research Institute, Roskilde (Denmark); Hertel, O. [National Environmental Research Institute, Roskilde (Denmark); Jensen, B. [National Environmental Research Institute, Roskilde (Denmark); Lundsgaard, C. [National Environmental Research Institute, Roskilde (Denmark); Markager, S.; Martinsen, W.; Moller, B.; Pedersen, B.; Sauerberg, K. [National Environmental Research Institute, Roskilde (Denmark); Sorensen, L.L.; Hasager, C.C. [Riso National Laboratory, Roskilde (Denmark); Sempreviva, A.M. [ISAC-CNR, Rome (Italy); Pryor, S.C. [Atmospheric Science Programme, Department of Geography, Indiana University, Bloomington, IN 47405 (United States); Lund, S.W.; Larsen, S. [Riso National Laboratory, Roskilde (Denmark); Tjernstroem, M.; Svensson, G.; Zagar, M. [Department of Meteorology, Stockholm University, Stockholm (Sweden)

    2006-04-15

    This paper summarises the results of the EU funded MEAD project, an interdisciplinary study of the effects of atmospheric nitrogen deposition on the Kattegat Sea between Denmark and Sweden. The study considers emissions of reactive nitrogen gases, their transport, transformations, deposition and effects on algal growth together with management options to reduce these effects. We conclude that atmospheric deposition is an important source of fixed nitrogen to the region particularly in summer, when nitrogen is the limiting nutrient for phytoplankton growth, and contributes to the overall eutrophication pressures in this region. However, we also conclude that it is unlikely that atmospheric deposition can, on its own, induce algal blooms in this region. A reduction of atmospheric nitrogen loads to this region will require strategies to reduce emissions of ammonia from local agriculture and Europe wide reductions in nitrous oxide emissions. - Atmospheric nitrogen deposition is an important factor in eutrophication processes in the Kattegat.

  7. Mead: An interdisciplinary study of the marine effects of atmospheric deposition in the Kattegat

    International Nuclear Information System (INIS)

    This paper summarises the results of the EU funded MEAD project, an interdisciplinary study of the effects of atmospheric nitrogen deposition on the Kattegat Sea between Denmark and Sweden. The study considers emissions of reactive nitrogen gases, their transport, transformations, deposition and effects on algal growth together with management options to reduce these effects. We conclude that atmospheric deposition is an important source of fixed nitrogen to the region particularly in summer, when nitrogen is the limiting nutrient for phytoplankton growth, and contributes to the overall eutrophication pressures in this region. However, we also conclude that it is unlikely that atmospheric deposition can, on its own, induce algal blooms in this region. A reduction of atmospheric nitrogen loads to this region will require strategies to reduce emissions of ammonia from local agriculture and Europe wide reductions in nitrous oxide emissions. - Atmospheric nitrogen deposition is an important factor in eutrophication processes in the Kattegat

  8. The Use of Biomonitors to Monitor Atmospheric Deposition of 210Pb

    International Nuclear Information System (INIS)

    The main source of 210Pb in the environment is the exhalation of 222Rn gas from the ground to the atmosphere during the radioactive decay of natural uranium - radium chain. In the atmosphere this radionuclide is rapidly attached to small particles - aerosols, predominantly on those particles below 0.3 mm. The half-life of 210Pb is longer than the atmospheric residence time of the aerosols on which it resides (1). By sedimentation and washout of aerosols this nuclide is then transferred to the soil or vegetation. The other main sources include burning of fossil fuels and phosphate fertilizers. The usual way to determine the levels of 210Pb and other radionuclides in the atmosphere is the use of a high volume filter system, which should operate for a long time to collect enough material for analysis. An other approach to determining the outdoor levels of radionuclides is the use of suitable biomonitors such as lichens or mosses. These organisms, although neither evolutionarie nor taxonomically related, have some common characteristics which enable them to be used as monitors for atmospheric pollution. They lack roots and protective organs against the substances derived from the atmosphere (stomata and cuticle) and are very efficient accumulators of atmospheric particulate material and chemical substances such as radionuclides or heavy metals (2). The levels of these substances in lichens and mosses are usually much higher than in air particulates or precipitation and for these reason the analysis is much easier. Another advantage of biomonitors over conventional sampling of air particulates or precipitation is that the collection of lichens or mosses is very cheap therefore allows a very large number of sites to be included in the same survey and permits detailed geographical deposition patterns to be drawn (3). It must be emphasised that concentration data on elements or radionuclides in lichens or mosses represent the relative deposition patterns over a certain

  9. Atmospheric wet and dry deposition of trace elements at ten sites in Northern China

    OpenAIRE

    Pan, Y. P.; Y. S. Wang

    2014-01-01

    Atmospheric deposition is considered to be a major process that removes pollutants from the atmosphere and an important source of nutrients and contaminants for ecosystems. Trace elements (TEs), especially toxic metals deposited on plants and into soil and water, can cause substantial damage to the environment and human health due to their transfer and accumulation in food chains. Despite public concerns, quantitative knowledge of metal deposition from the a...

  10. Integrated Assessment of Ecosystem Effects of Atmospheric Deposition

    Science.gov (United States)

    Ecosystems obtain a portion of their nutrients from the atmosphere. Following the Industrial Revolution, however, human activities have accelerated biogeochemical cycles, greatly enhancing the transport of substances among the atmosphere, water, soil, and living things. The atmos...

  11. Atmospheric deposition of trace elements around Ulan Bator city studied by moss and lichen biomonitoring technique and INAA

    International Nuclear Information System (INIS)

    For the first time the moss and lichen biomonitoring technique has been applied to air pollution in Mongolia (Ulan-Bator, the capital city). INAA at the IBR-2 reactor has made it possible to determine the content of 35 elements in moss and lichen biomonitors. Samples collected at sites located 10-15 km from the center of Ulan-Bator were analyzed by Instrumental Neutron Activation Analysis (INAA) using epithermal neutrons. The mosses (Rhytidium rugosum, Thuidium abietinum, Entodon concinnus) and lichens (Cladonia stellaris, Parmelia separata) were used to study the atmospheric deposition of trace elements. It was shown that the suggested types of mosses could be used as suitable biomonitors to estimate the concentration levels of heavy metals and trace elements in Ulan-Bator atmospheric deposition. The results are compared to the data of atmospheric deposition of some European countries

  12. Atmospheric Deposition of Trace Elements Around Ulan-Bator City Studied by Moss and Lichen Biomonitoring Technique and INAA

    CERN Document Server

    Ganbold, G; Gundorina, S F; Frontasyeva, M V; Ostrovnaya, T M; Pavlov, S S; Tsendeekhuu, T

    2005-01-01

    For the first time the moss and lichen biomonitoring technique has been applied to air pollution in Mongolia (Ulan-Bator, the capital city). INAA at the IBR-2 reactor has made it possible to determine the content of 35 elements in moss and lichen biomonitors. Samples collected at sites located 10-15 km from the center of Ulan-Bator were analyzed by Instrumental Neutron Activation Analysis (INAA) using epithermal neutrons. The mosses (\\textit{Rhytidium rugosum}, \\textit{Thuidium abietinum}, \\textit{Entodon concinnus}) and lichens (\\textit{Cladonia stellaris}, \\textit{Parmelia separata}) were used to study the atmospheric deposition of trace elements. It was shown that the suggested types of mosses could be used as suitable biomonitors to estimate the concentration levels of heavy metals and trace elements in Ulan-Bator atmospheric deposition. The results are compared to the data of atmospheric deposition of some European countries.

  13. Time variant layer control in atmospheric pressure chemical vapor deposition based growth of graphene

    KAUST Repository

    Qaisi, Ramy M.

    2013-04-01

    Graphene is a semi-metallic, transparent, atomic crystal structure material which is promising for its high mobility, strength and transparency - potentially applicable for radio frequency (RF) circuitry and energy harvesting and storage applications. Uniform (same number of layers), continuous (not torn or discontinuous), large area (100 mm to 200 mm wafer scale), low-cost, reliable growth are the first hand challenges for its commercialization prospect. We show a time variant uniform (layer control) growth of bi- to multi-layer graphene using atmospheric chemical vapor deposition system. We use Raman spectroscopy for physical characterization supported by electrical property analysis. © 2013 IEEE.

  14. Atmospheric Sulfur Deposition for a Red Soil Broadleaf Forest in Southern China

    Institute of Scientific and Technical Information of China (English)

    XU Cheng-Kai; HU Zheng-Yi; CAI Zu-Cong; WANG Ti-Jian; HE Yuan-Qiu; CAO Zhi-Hong

    2004-01-01

    A two-year study in a typical red soil region of Southern China was conducted to determine 1) the dry deposition velocity (Vd) for SO2 and particulate SO2 4- above a broadleaf forest, and 2) atmospheric sulfur fluxes so as to estimate the contribution of various fractions in the total. Using a resistance model based on continuous hourly meteorological data, atmospheric dry sulfur deposition in a forest was estimated according to Vd and concentrations of both atmospheric SO2 and particulate SO24-. Meanwhile, wet S deposition was estimated based on rainfall and sulfate concentrations in the rainwater. Results showed that about 99% of the dry sulfur deposition flux in the forest resulted from SO2 dry deposition.In addition, the observed dry S deposition was greater in 2002 than in 2000 because of a higher average concentration of SO2 in 2002 than in 2000 and not because of the average dry deposition velocity which was lower for SO2 in 2002. Also,dry SO2 deposition was the dominant fraction of deposited atmospheric sulfur in forests, contributing over 69% of the total annual sulfur deposition. Thus, dry SO2 deposition should be considered when estimating sulfur balance in forest ecological systems.

  15. Contribution of atmospheric deposition to tissue concentrations of mercury in aquatic bryophytes.

    Science.gov (United States)

    Villares, Rubén; Díaz, Santiago; López, Jesús; Vázquez, Maria Dolores; Carballeira, Alejo

    2016-09-15

    In this biomonitoring study, we measured the temporal variations in concentrations of mercury in samples of aquatic bryophytes from rivers in a region that received large inputs of the metal via atmospheric deposition. In the first year of sampling, the presence of an important source of atmospheric deposition of Hg (a lignite-fired power plant) led, during the rainy season, to elevated concentrations of the metal in catchments situated downwind of the prevailing winds. High concentrations of the metal were even detected in samples from apparently clean rivers in isolated mountain sites within the downwind catchments. Substitution of the type of fuel (high quality imported carbon instead of brown coal) used in the power plant greatly reduced Hg emissions in subsequent years. Application of spatial interpolation techniques to dense monitoring networks with aquatic bryophytes, without taking into consideration the catchment borders, appears suitable for studying extensive atmospheric pollution derived from a large scale source of contamination. This study also demonstrates the importance of environmental specimen banks in retrospective studies of contamination, as they enable posterior analysis of contaminants that for various reasons cannot be analyzed at the time of sampling. PMID:27177131

  16. Atmospheric heavy metal deposition accumulated in rural forest soils of southern Scandinavia

    International Nuclear Information System (INIS)

    Thirty-three years of measurements of atmospheric heavy metal (HM) deposition (bulk precipitation) in Denmark combined with European emission inventories form the basis for calculating a 50-year accumulated atmospheric input to a remote forest plantation on the island of Laesoe. Soil samples taken in two depths, 0-10 cm and 10-20 cm, at eight forest sites at the island were used to determine the increase in HM content in the eolian deposited top soils of the plantation. Concentrations of lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn), vanadium (V), nickel (Ni) and arsenic (As) were determined in atmospheric deposition and in soils. The accumulated atmospheric deposition is of the same magnitude as the increase of these metals in the top soil. - The accumulated atmospheric input of heavy metals determined through continuous measurements during 33 years is compared to the rise in the metal content of forest top soils at rural remote sites

  17. Atmospheric mercury deposition recorded in an ombrotrophic peat core from Xiaoxing'an Mountain, Northeast China

    International Nuclear Information System (INIS)

    The historical mercury accumulation rates (Hg AR) resulting from atmospheric deposition to Xiaoxing'an Mountain were determined via analysis of 210Pb- and 14C-dated cores up to 5000 years old. Natural Hg AR background, pre-industrial Hg AR and maximum industrial Hg AR in Northeast China were 2.2 ±1.0 μg/m2/yr for 5100–4500 BP, 5.7 μg/m2/yr and 112.4 μg/m2/yr, respectively. We assumed that the increase in Hg deposition in the Xiaoxing'an mountain area during industrial time was mainly attributed to local anthropogenic emissions around this peat bog.

  18. Multielement atmospheric deposition study in Croatia using moss biomonitoring, NAA, AAS and GIS technologies

    International Nuclear Information System (INIS)

    For the first time the moss biomonitoring technique and two complementary analytical techniques - neutron activation analysis (NAA) and atomic absorption spectrometry (AAS) - were applied to study multielement atmospheric deposition in the Republic of Croatia. Moss samples were collected during the summer 2006 from 98 sites evenly distributed over the country. Sampling was performed in accordance with the LRTAP Convention - ICP Vegetation protocol and sampling strategy of the European Programme on Biomonitoring of Heavy Metal Atmospheric Deposition. Conventional and epithermal neutron activation analyses made it possible to determine concentrations of 41 elements including key heavy metals such as Pb, Cd, Hg, and Cu determined by AAS. Principal component analysis (factor analysis with VARIMAX rotation) was applied to distinguish elements mainly of anthropogenic origin from those predominantly originating from natural sources. Geographical distribution maps of the elements over the sampled territory were constructed using GIS technology. The median values for Croatia are consistent with the corresponding values for all Europe for most elements. It was shown that the Adriatic coastline of Croatia may be considered as an environmentally pristine area. This study was conducted for providing reliable assessment of air quality throughout Croatia and producing information needed for better identification of pollution sources and improving the potential for assessing environmental and health risks in Croatia associated with toxic metals

  19. Deposition of silicon oxide like films from HMDSO by means of atmospheric pressure microplasma jets: Study of deposition mechanisms

    CERN Document Server

    Reuter, R; Ellerweg, D; Arcos, T de los; von Keudell, A; Benedikt, J

    2011-01-01

    The deposition of thin SiOxCyH or SiOxHy films by means of atmospheric pressure microplasma jets with Helium / Hexamethyldisiloxane (HMDSO / O2) mixtures and the role of surface reactions for the film growth have been investigated. The growth rate and the carbon-content in the film are measured as a function of the O2 and HMDSO mixture in the gas flow. Two types of microplasma jets, one with a planar and one with a coaxial geometry, are used to study the deposition process. The very localised deposition on and treatment of the surface gives the opportunity to separate deposition and treatment processes by applying two jets on a rotating substrate. The etching of carbon at the surface and the increasing HMDSO depletion leading to an increasing deposition rate are both induced by admixing oxygen. Carbon free films can be deposited, even without addition of oxygen, and the main loss channels for carbon are surface reactions.

  20. Further promotion of the use of mosses and lichens for studies of atmospheric deposition of trace elements

    International Nuclear Information System (INIS)

    Some recent and ongoing studies related to the use of mosses as biomonitors of atmospheric metal deposition are briefly reviewed. Issues discussed in particular are the conversion of concentration in moss to absolute deposition values, introduction of a second-generation ICP-MS instrument for moss analysis, determination of stable lead isotope ratios in mosses for source apportionment, and temporal trends of lead and cadmium deposition in Norway. A novel nuclear technique for the determination of fluorine in mosses surrounding an aluminium smelter is presented. (author)

  1. Deposition of atmospheric 210Pb and total beta activity in Finland

    International Nuclear Information System (INIS)

    The seasonal and regional variation of the atmospheric 210Pb deposition in Finland was studied. The 210Pb activity concentration in precipitation shows a decreasing trend from southeastern Finland north-westwards. An average deposition of 40 Bq/m2 during a 12 months period was observed. The deposition of 210Pb shows a seasonal variation with minimum in spring and maximum in autumn and winter. The specific activity of 210Pb (activity of 210Pb per unit mass of stable lead) in the atmosphere has returned to the level prior to World War II owing to the reduced lead emissions into the atmosphere. (author)

  2. Wet and Dry Atmospheric Depositions of Inorganic Nitrogen during Plant Growing Season in the Coastal Zone of Yellow River Delta

    OpenAIRE

    Junbao Yu; Kai Ning; Yunzhao Li; Siyao Du; Guangxuan Han; Qinghui Xing; Huifeng Wu; Guangmei Wang; Yongjun Gao

    2014-01-01

    The ecological problems caused by dry and wet deposition of atmospheric nitrogen have been widespread concern in the world. In this study, wet and dry atmospheric depositions were monitored in plant growing season in the coastal zone of the Yellow River Delta (YRD) using automatic sampling equipment. The results showed that SO4 2− and Na+ were the predominant anion and cation, respectively, in both wet and dry atmospheric depositions. The total atmospheric nitrogen deposition was ~2264.24 mg ...

  3. Seasonal and spatial variations of atmospheric trace elemental deposition in the Aliaga industrial region, Turkey

    Science.gov (United States)

    Kara, Melik; Dumanoglu, Yetkin; Altiok, Hasan; Elbir, Tolga; Odabasi, Mustafa; Bayram, Abdurrahman

    2014-11-01

    Atmospheric bulk deposition (wet + dry deposition) samples (n = 40) were collected concurrently at ten sites in four seasons between June 2009 and April 2010 in the Aliaga heavily industrialized region, Turkey, containing a number of significant air pollutant sources. Analyses of trace elements were carried out using inductively coupled plasma-mass spectrometry (ICP-MS). While there were significant differences in the particulate matter (PM) deposition fluxes among the sampling sites, seasonal variations were not statistically significant (Kruskal-Wallis test, p deposition and elemental fluxes were increased at the sampling sites in the vicinity of industrial activities. The crustal elements (i.e., Ca, Mg) and some anthropogenic elements (such as Fe, Zn, Mn, Pb, Cu, and Cr) were high, and the highest fluxes were mostly measured in summer and winter seasons. The enrichment factor (EF) and principal component analysis (PCA) was applied to the data to determine the possible sources in the study area. High EF values were obtained for the anthropogenic elements such as Ag, Cd, Zn, Pb, Cu and Sb. The possible sources were identified as anthropogenic sources (i.e., iron-steel production) (45.4%), crustal and re-suspended dust (27.1%), marine aerosol (7.9%), and coal and wood combustion (8.2%). Thus, the iron-steel production and its related activities were found to be the main pollutant sources for this region.

  4. Contribution of Asian dust to atmospheric deposition of radioactive cesium ((137)Cs).

    Science.gov (United States)

    Fukuyama, Taijiro; Fujiwara, Hideshi

    2008-11-01

    Both Asian dust (kosa) transported from the East Asian continent and locally suspended dust near monitoring sites contribute to the observed atmospheric deposition of (137)Cs in Japan. To estimate the relative contribution of these dust phenomena to the total (137)Cs deposition, we monitored weekly deposition of mineral particles and (137)Cs in spring. Deposition of (137)Cs from a single Asian dust event was 62.3 mBq m(-2) and accounted for 67% of the total (137)Cs deposition during the entire monitoring period. Furthermore, we found high (137)Cs specific activity in the Asian dust deposition sample. Although local dust events contributed to (137)Cs deposition, their contribution was considerably smaller than that of Asian dust. We conclude that the primary source of atmospheric (137)Cs in Japan is dust transported from the East Asian continent.

  5. External quality assurance project report for the National Atmospheric Deposition Program’s National Trends Network and Mercury Deposition Network, 2013–14

    Science.gov (United States)

    Wetherbee, Gregory A.; Martin, RoseAnn

    2016-07-05

    The U.S. Geological Survey Branch of Quality Systems operated five distinct programs to provide external quality assurance monitoring for the National Atmospheric Deposition Program’s (NADP) National Trends Network and Mercury Deposition Network during 2013–14. The National Trends Network programs include (1) a field audit program to evaluate sample contamination and stability, (2) an interlaboratory comparison program to evaluate analytical laboratory performance, and (3) a colocated sampler program to evaluate bias from precipitation sampler upgrades. The Mercury Deposition Network programs include the (4) system blank program and (5) an interlaboratory comparison program. The results indicate that NADP data continue to be of sufficient quality for the analysis of spatial distributions and time trends for chemical constituents in wet deposition.

  6. External quality assurance project report for the National Atmospheric Deposition Program’s National Trends Network and Mercury Deposition Network, 2013–14

    Science.gov (United States)

    Wetherbee, Gregory A.; Martin, RoseAnn

    2016-01-01

    The U.S. Geological Survey Branch of Quality Systems operated five distinct programs to provide external quality assurance monitoring for the National Atmospheric Deposition Program’s (NADP) National Trends Network and Mercury Deposition Network during 2013–14. The National Trends Network programs include (1) a field audit program to evaluate sample contamination and stability, (2) an interlaboratory comparison program to evaluate analytical laboratory performance, and (3) a colocated sampler program to evaluate bias from precipitation sampler upgrades. The Mercury Deposition Network programs include the (4) system blank program and (5) an interlaboratory comparison program. The results indicate that NADP data continue to be of sufficient quality for the analysis of spatial distributions and time trends for chemical constituents in wet deposition.

  7. Atmospheric deposition of mercury in central Poland: Sources and seasonal trends

    Science.gov (United States)

    Siudek, Patrycja; Kurzyca, Iwona; Siepak, Jerzy

    2016-03-01

    Atmospheric deposition of total mercury was studied at two sites in central Poland, between April 2013 and October 2014. Hg in rainwater (bulk deposition) was analyzed in relation to meteorological parameters and major ions (H+, NO3-, Cl-, SO42 -) in order to investigate seasonal variation, identify sources and determine factors affecting atmospheric Hg chemistry and deposition. Total mercury concentrations varied between 1.24 and 22.1 ng L- 1 at the urban sampling site (Poznań) and between 0.57 and 18.3 ng L- 1 in the woodland protected area (Jeziory), with quite similar mean values of 6.96 and 6.37 ng L- 1, respectively. Mercury in precipitation exhibited lower spatial variability within the study domain (urban/forest transect) than the concentrations determined during other similar observations, reflecting the predominant influence of the same local sources. In our study, a significant seasonal pattern of Hg deposition was observed at both sampling sites, with higher and more variable concentrations of Hg reported for the urban area. In particular, deposition values of Hg were higher in the samples attributed to relatively large precipitation amounts in the summer and in those collected during the winter season (the result of higher contributions from combustion sources, i.e. intensive combustion of fossil fuels in residential and commercial boilers, individual power/heat-generating plants). In addition, a significant relationship between Hg concentration and precipitation amount was found while considering different types of wintertime samples (i.e. rain, snow and mixed precipitation). The analysis of backward trajectories showed that air masses arriving from polluted regions of western Europe and southern Poland largely affected the amount of Hg in rainwater. A seasonal variation in Hg deposition fluxes was also observed, with the maximum value of Hg in spring and minimum in winter. Our results indicated that rainwater Hg and, consequently, the wet deposition

  8. Atmospheric wet and dry deposition of trace elements at ten sites in Northern China

    Directory of Open Access Journals (Sweden)

    Y. P. Pan

    2014-08-01

    Full Text Available Atmospheric deposition is considered to be a major process that removes pollutants from the atmosphere and an important source of nutrients and contaminants for ecosystems. Trace elements (TEs, especially toxic metals deposited on plants and into soil and water, can cause substantial damage to the environment and human health due to their transfer and accumulation in food chains. Despite public concerns, quantitative knowledge of metal deposition from the atmosphere to ecosystems remains scarce. To advance our understanding of the spatio-temporal variations in the magnitudes, pathways, compositions and impacts of atmospherically deposited TEs, precipitation (rain and snow and dry-deposited particles were collected simultaneously at ten sites in Northern China from December 2007 to November 2010. The measurements showed that the wet and dry depositions of TEs in the target areas were orders of magnitude higher than previous observations within and outside China, generating great concern over the potential risks. The spatial distribution of the total (wet plus dry deposition flux was consistent with that of the dry deposition, with a significant decrease from industrial and urban areas to suburban, agricultural and rural sites. In contrast, the wet deposition exhibited less spatial variation. The seasonal variation of wet deposition was also different from that of dry deposition, although they were both governed by the precipitation and emission patterns. For the majority of TEs that exist as coarse particles, dry deposition dominated the total flux at each site. This was not the case for K, Ni, As, Pb, Zn, Cd, Se, Ag and Tl, for which the relative importance between wet and dry deposition fluxes varied by site. Whether wet deposition is the major atmospheric cleansing mechanism for the TEs depends on the size distribution and solubility of the particles. We found that atmospheric inputs of Cu, Pb, Zn, Cd, As and Se were of the same magnitude as

  9. Atmospheric wet and dry deposition of trace elements at 10 sites in Northern China

    Science.gov (United States)

    Pan, Y. P.; Wang, Y. S.

    2015-01-01

    Atmospheric deposition is considered to be a major process that removes pollutants from the atmosphere and an important source of nutrients and contaminants for ecosystems. Trace elements (TEs), especially toxic metals deposited on plants and into soil or water, can cause substantial damage to the environment and human health due to their transfer and accumulation in food chains. Despite public concerns, quantitative knowledge of metal deposition from the atmosphere to ecosystems remains scarce. To advance our understanding of the spatiotemporal variations in the magnitudes, pathways, compositions and impacts of atmospherically deposited TEs, precipitation (rain and snow) and dry-deposited particles were collected simultaneously at 10 sites in Northern China from December 2007 to November 2010. The measurements showed that the wet and dry depositions of TEs in the target areas were orders of magnitude higher than previous observations within and outside China, generating great concern over the potential risks. The spatial distribution of the total (wet plus dry) deposition flux was consistent with that of the dry deposition, with a significant decrease from industrial and urban areas to suburban, agricultural and rural sites, while the wet deposition exhibited less spatial variation. In addition, the seasonal variation of wet deposition was also different from that of dry deposition, although they were both governed by the precipitation and emission patterns. For the majority of TEs that exist as coarse particles, dry deposition dominated the total flux at each site. This was not the case for potassium, nickel, arsenic, lead, zinc, cadmium, selenium, silver and thallium, for which the relative importance between wet and dry deposition fluxes varied by site. Whether wet deposition is the major atmospheric cleansing mechanism for the TEs depends on the size distribution of the particles. We found that atmospheric inputs of copper, lead, zinc, cadmium, arsenic and

  10. MEAD: an interdisciplinary study of the marine effects of atmospheric deposition in the Kattegat.

    Science.gov (United States)

    Spokes, L; Jickells, T; Weston, K; Gustafsson, B G; Johnsson, M; Liljebladh, B; Conley, D; Ambelas-Skjødth, C; Brandt, J; Carstensen, J; Christiansen, T; Frohn, L; Geernaert, G; Hertel, O; Jensen, B; Lundsgaard, C; Markager, S; Martinsen, W; Møller, B; Pedersen, B; Sauerberg, K; Sørensen, L L; Hasager, C C; Sempreviva, A M; Pryor, S C; Lund, S W; Larsen, S; Tjernström, M; Svensson, G; Zagar, M

    2006-04-01

    This paper summarises the results of the EU funded MEAD project, an interdisciplinary study of the effects of atmospheric nitrogen deposition on the Kattegat Sea between Denmark and Sweden. The study considers emissions of reactive nitrogen gases, their transport, transformations, deposition and effects on algal growth together with management options to reduce these effects. We conclude that atmospheric deposition is an important source of fixed nitrogen to the region particularly in summer, when nitrogen is the limiting nutrient for phytoplankton growth, and contributes to the overall eutrophication pressures in this region. However, we also conclude that it is unlikely that atmospheric deposition can, on its own, induce algal blooms in this region. A reduction of atmospheric nitrogen loads to this region will require strategies to reduce emissions of ammonia from local agriculture and Europe wide reductions in nitrous oxide emissions. PMID:16271430

  11. Atmospheric heavy metal deposition accumulated in rural forest soils of southern Scandinavia

    DEFF Research Database (Denmark)

    Hovmand, Mads Frederik; Kemp, Kaare; Kystol, J.;

    2008-01-01

    Thirty-three years of measurements of atmospheric heavy metal (HM) deposition (bulk precipitation) in Denmark combined with European emission inventories form the basis for calculating a 50-year accumulated atmospheric input to a remote forest plantation on the island of Laesoe. Soil samples taken...... in atmospheric deposition and in soils. The accumulated atmospheric deposition is of the same magnitude as the increase of these metals in the top soil....... in two depths, 0-10 cm and 10-20 cm, at eight forest sites at the island were used to determine the increase in HM content in the eolian deposited top soils of the plantation. Concentrations of lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn), vanadium (V), nickel (Ni) and arsenic (As) were determined...

  12. Puff-plume atmospheric deposition model for use at SRP in emergency-response situations

    International Nuclear Information System (INIS)

    An atmospheric transport and diffusion model developed for real-time calculation of the location and concentration of toxic or radioactive materials during an accidental release was improved by including deposition calculations

  13. FTIR analysis of aviation fuel deposits

    Science.gov (United States)

    Helmick, L. S.; Seng, G. T.

    1984-01-01

    Five modes of operation of the Nicolet 7199 Fourier Transform Infrared Spectrophotometer have been evaluated for application in analysis of the chemical structure of accelerated storage/thermal deposits produced by jet fuels. Using primarily the absorption and emission modes, the effects of fuel type, stress temperature, stress time, type of spiking agent, spiking agent concentration, fuel flow, and post-depositional treatment on the chemical nature of fuel deposits have been determined.

  14. Wet and dry deposition of atmospheric nitrogen at ten sites in Northern China

    Directory of Open Access Journals (Sweden)

    Y. P. Pan

    2012-01-01

    Full Text Available Emissions of reactive nitrogen (N species can affect surrounding ecosystems via atmospheric deposition. However, few long-term and multi-site measurements have focused on both the wet and the dry deposition of individual N species in large areas of Northern China. Thus, the magnitude of atmospheric deposition of various N species in Northern China remains uncertain. In this study, the wet and dry atmospheric deposition of different N species was investigated during a three-year observation campaign at ten selected sites in Northern China. The results indicate that N deposition levels in Northern China were high with a ten-site, three-year average of 60.6 kg N ha−1 yr−1. The deposition levels showed spatial and temporal variation in the range of 28.5–100.4 kg N ha−1 yr−1. Of the annual total deposition, 40% was deposited via precipitation, and the remaining 60% was comprised of dry-deposited forms. Compared with gaseous N species, particulate N species were not the major contributor of dry-deposited N; they contributed approximately 10% to the total flux. On an annual basis, oxidized species accounted for 21% of total N deposition, thereby implying that other forms of gaseous N, such as NH3, comprised a dominant portion of the total flux. The contribution of NO3 to N deposition was enhanced in certain urban and industrial areas. As expected, the total N deposition in Northern China was significantly larger than the values reported by national scale monitoring networks in Europe, North America and East Asia because of high rates of wet deposition and gaseous NH3 dry deposition. The results have three important implications. First, atmospheric N deposition in Northern China falls within the range of critical loads for temperate forests and grasslands, a threshold above which harmful ecological effects to specified parts of temperate ecosystems often

  15. Relationships Between Long-term Atmospheric Wet Deposition and Stream Chemistry in Mid-Appalachian Forest Catchments

    Science.gov (United States)

    DeWalle, D. R.; Boyer, E. W.; Buda, A. R.

    2014-12-01

    Improved understanding of the link between atmospheric deposition and surface water quality is critical to assessing the degree to which forested watersheds have recovered from acidification. This presentation draws upon long-term (1982-2013) atmospheric wet deposition and stream chemistry time series to study how changes in atmospheric chemical inputs have been propagated to stream waters. We used autocorrelation and lagged cross-correlation techniques to analyze monthly time series describing variations of chloride, sulfate and inorganic nitrogen concentrations for four pairs of stream/deposition monitoring sites. Autocorrelation analysis revealed that individual atmospheric input time series of sulfate and inorganic nitrogen were strongly seasonal, while chloride inputs exhibited little seasonality. Stream chemistry time series exhibited gradually declining autocorrelation trends with increasing lag times suggesting that atmospheric input signals were variably damped by the forest ecosystems . Lagged cross-correlation between raw atmospheric and stream chemistry time series indicated gradual decreases in correlation within superimposed regular annual cycles of correlation over 10- 15 years of lag time. Pre-whitening of each atmospheric and stream time series using regression or ARIMA models removed the influence of long-term trends, seasonal cycles and other factors and revealed occurrence of relatively few and highly variable lag times with significant correlations. While lagged cross-correlation of raw time series data provided some useful insights into the long-term trend and seasonal nature of the linkages between atmospheric deposition and stream chemistry, cross-correlation of shorter-term residual variations after prewhitening did not produce a consistent pattern of lag times with significant correlations in our monthly time series data.

  16. Chinese coastal seas are facing heavy atmospheric nitrogen deposition

    Science.gov (United States)

    Luo, X. S.; Tang, A. H.; Shi, K.; Wu, L. H.; Li, W. Q.; Shi, W. Q.; Shi, X. K.; Erisman, J. W.; Zhang, F. S.; Liu, X. J.

    2014-09-01

    As the amount of reactive nitrogen (N) generated and emitted increases the amount of N deposition and its contribution to eutrophication or harmful algal blooms in the coastal zones are becoming issues of environmental concern. To quantify N deposition in coastal seas of China we selected six typical coastal sites from North to South in 2011. Concentrations of NH3, HNO3, NO2, particulate NH4+ (pNH4+) and pNO3- ranged from 1.97- 4.88, 0.46 -1.22, 3.03 -7.09, 2.24 - 4.90 and 1.13-2.63 μg N m-3 at Dalian (DL), Changdao (CD), Linshandao (LS), Fenghua (FH), Fuzhou (FZ), and Zhanjiang (ZJ) sites, respectively. Volume-weighted NO3--N and NH4+-N concentrations in precipitation varied from 0.46 to 1.67 and 0.47 to 1.31 mg N L-1 at the six sites. Dry, wet and total deposition rates of N were 7.8-23.1, 14.2-25.2 and 22.0 - 44.6 kg N ha-1 yr-1 across the six coastal sites. Average N dry deposition accounted for 45.4% of the total deposition and NH3 and pNH4+ contributed to 76.6% of the dry deposition. If we extrapolate our total N deposition of 33.9 kg N ha-1 yr-1 to the whole Chinese coastal sea area (0.40 million km2), total N deposition amounts to 1.36 Tg N yr-1, a large external N input to surrounding marine ecosystems.

  17. Chinese coastal seas are facing heavy atmospheric nitrogen deposition

    International Nuclear Information System (INIS)

    As the amount of reactive nitrogen (N) generated and emitted increases the amount of N deposition and its contribution to eutrophication or harmful algal blooms in the coastal zones are becoming issues of environmental concern. To quantify N deposition in coastal seas of China we selected six typical coastal sites from North to South in 2011. Concentrations of NH3, HNO3, NO2, particulate NH4+ (pNH4+) and pNO3− ranged from 1.97– 4.88, 0.46 –1.22, 3.03 –7.09, 2.24 – 4.90 and 1.13–2.63 μg N m−3 at Dalian (DL), Changdao (CD), Linshandao (LS), Fenghua (FH), Fuzhou (FZ), and Zhanjiang (ZJ) sites, respectively. Volume-weighted NO3−–N and NH4+–N concentrations in precipitation varied from 0.46 to 1.67 and 0.47 to 1.31 mg N L−1 at the six sites. Dry, wet and total deposition rates of N were 7.8–23.1, 14.2–25.2 and 22.0 – 44.6 kg N ha−1 yr−1 across the six coastal sites. Average N dry deposition accounted for 45.4% of the total deposition and NH3 and pNH4+ contributed to 76.6% of the dry deposition. If we extrapolate our total N deposition of 33.9 kg N ha−1 yr−1 to the whole Chinese coastal sea area (0.40 million km2), total N deposition amounts to 1.36 Tg N yr−1, a large external N input to surrounding marine ecosystems. (paper)

  18. Laser induced chemical vapour deposition of TiN coatings at atmospheric pressure

    OpenAIRE

    Croonen, Y.; Verspui, G.

    1993-01-01

    Laser induced Chemical Vapour Deposition of a wide variety of materials has been studied extensively at reduced pressures. However, for this technique to be economically and industrially applicable, processes at atmospheric pressure are preferred. A model study was made on the substrate-coating system molybdenum-titaniumnitride focussing on the feasibility to deposit TiN films locally at atmospheric pressure. The results of this study turned out to be very promising. A Nd-YAG laser beam ([MAT...

  19. Modeling atmospheric deposition using a stochastic transport model

    International Nuclear Information System (INIS)

    An advanced stochastic transport model has been modified to include the removal mechanisms of dry and wet deposition. Time-dependent wind and turbulence fields are generated with a prognostic mesoscale numerical model and are used to advect and disperse individually released particles that are each assigned a mass. These particles are subjected to mass reduction in two ways depending on their physical location. Particles near the surface experience a decrease in mass using the concept of a dry deposition velocity, while the mass of particles located within areas of precipitation are depleted using a scavenging coefficient. Two levels of complexity are incorporated into the particle model. The simple case assumes constant values of dry deposition velocity and scavenging coefficient, while the more complex case varies the values according to meteorology, surface conditions, release material, and precipitation intensity. Instantaneous and cumulative dry and wet deposition are determined from the mass loss due to these physical mechanisms. A useful means of validating the model results is with data available from a recent accidental release of Cesium-137 from a steel-processing furnace in Algeciras, Spain in May, 1998. This paper describes the deposition modeling technique, as well as a comparison of simulated concentration and deposition with measurements taken for the Algeciras release

  20. Total Sulfur Deposition (wet+dry) from the Atmosphere

    Data.gov (United States)

    U.S. Environmental Protection Agency — Sulfur Dioxide (SO2) is emitted primarily as a by-product of coal combustion from power plants. Sulfur Dioxide reacts in the atmosphere to form other chemical such...

  1. Internationally harmonised approach to biomonitoring trace element atmospheric deposition

    International Nuclear Information System (INIS)

    The International Atomic Energy Agency (IAEA) has been supporting work on airborne particulate matter since 1992 through various co-ordinated research and technical co-operation projects. In 1997, biomonitoring air pollution using plants, became officially a part of the IAEA project on environmental pollution monitoring and research. Based on: (1) positive experience in using biomonitors, especially lower plants such as mosses and lichens in several developed countries; (2) the continuous use of biomonitors in several Member States; and (3) the fact that nuclear and related analytical techniques have been shown to be particularly appropriate for the analysis of air pollution biomonitors, such studies are now being supported by the IAEA in 14 countries within a co-ordinated research project. The main emphasis of this project is on (1) identification of suitable biomonitors of atmospheric pollution for local and/or regional application, and (2) their validation for general environmental monitoring, whenever possible. Although the participants are using different plants as biomonitors in their research in geographically and climatically diverse parts of the world, they are harmonising sampling approaches and analytical procedures. In this paper, an overview of these activities is given, along with the details, where possible. In all of these activities, proficiency testing and analytical quality assurance are important issue, which merits special attention. To this end, a variety of analytical quality control materials have been used in intercomparison exercises and proficiency testing. Within the scope of the NAT-5 intercomparison exercise, two lichen materials were distributed among 15 participating laboratories and a proficiency test was organised. The results obtained proved satisfactory performance for most participating laboratories. (author)

  2. Global atmospheric energy deposition by energetic electrons - Quantitative spatial and temporal characteristics inferred from the Atmospheric X-ray Imaging Spectrometer (PEM/AXIS) on UARS

    Science.gov (United States)

    Chenette, D. L.; Datlowe, D. W.; Robinson, R. M.; Schumaker, T. L.; Vondrak, R. R.; Frahm, R. A.; Sharber, J. R.; Winningham, J. D.

    1993-01-01

    The primary purpose of PEM/AXIS is to provide a global monitor of the energy input to the upper atmosphere due to energetic electrons. The design, development, and calibration of AXIS are described and an assessment of its excellent on-orbit performance is presented. The unique capabilities of X-ray imaging spectrometers to monitor the global patterns of electron energy deposition in the atmosphere are shown through an analysis of some specific cases during the first year of the UARS mission.

  3. High-throughput processes for industrially scalable deposition of zinc oxide at atmospheric pressure

    NARCIS (Netherlands)

    Illiberi, A.; Grob, F.; Kniknie, B.; Frijters, C.; Deelen, J. van; Poodt, P.; Beckers, E.H.A.; Bolt, P.J.

    2014-01-01

    ZnO films have been grown on a moving glass substrate by high temperature (480 0C) chemical vapour deposition (CVD) and low temperature (200 0C) plasma enhanced CVD (PE-CVD) process at atmospheric pressure. Deposition rates above 7 nm/s have been achieved for substrate speeds from 20 to 500 mm/min.

  4. Source receptor relations for the calculation of atmospheric deposition to the North Sea: Nitrogen and Cadmium

    NARCIS (Netherlands)

    van Jaarsveld JA; de Leeuw FAAM

    1993-01-01

    In this report a simplified atmospheric transport model for estimating the deposition of nitrogen (both NOx and NHx) and cadmium to the North Sea is presented. In this so-called meta-model a linear relationship between the emissions from a source area and the resulting deposition at receptor points

  5. Atmospheric Deposition of Heavy Metals in Soil Affected by Different Soil Uses of Southern Spain

    Science.gov (United States)

    Acosta, J. A.; Faz, A.; Martínez-Martínez, S.; Bech, J.

    2009-04-01

    Heavy metals are a natural constituent of rocks, sediments and soils. However, the heavy metal content of top soils is also dependent on other sources than weathering of the indigenous minerals; input from atmospheric deposition seems to be an important pathway. Atmospheric deposition is defined as the process by which atmospheric pollutants are transferred to terrestrial and aquatic surfaces and is commonly classified as either dry or wet. The interest in atmospheric deposition has increased over the past decade due to concerns about the effects of deposited materials on the environment. Dry deposition provides a significant mechanism for the removal of particles from the atmosphere and is an important pathway for the loading of heavy metals into the soil ecosystem. Within the last decade, an intensive effort has been made to determine the atmospheric heavy metal deposition in both urban and rural areas. The main objective of this study was to identification of atmospheric heavy metals deposition in soil affected by different soil uses. Study area is located in Murcia Province (southeast of Spain), in the surroundings of Murcia City. The climate is typically semiarid Mediterranean with an annual average temperature of 18°C and precipitation of 350 mm. In order to determine heavy metals atmospheric deposition a sampling at different depths (0-1 cm, 1-5 cm, 5-15 cm and 15-30 cm) was carried out in 7 sites including agricultural soils, two industrial areas and natural sites. The samples were taken to the laboratory where, dried, passed through a 2 mm sieve, and grinded. For the determination of the moisture the samples were weighed and oven dried at 105 °C for 24 h. The total amounts of metals (Pb, Cu, Pb, Zn, Cd, Mn, Ni and Cr) were determined by digesting the samples with nitric/perchoric acids and measuring with ICP-MS. Results showed that zinc contamination in some samples of industrial areas was detected, even this contamination reaches 30 cm depth; thus it is

  6. Quantifying atmospheric nitrogen deposition through a nationwide monitoring network across China

    Science.gov (United States)

    Xu, W.; Luo, X. S.; Pan, Y. P.; Zhang, L.; Tang, A. H.; Shen, J. L.; Zhang, Y.; Li, K. H.; Wu, Q. H.; Yang, D. W.; Zhang, Y. Y.; Xue, J.; Li, W. Q.; Li, Q. Q.; Tang, L.; Lu, S. H.; Liang, T.; Tong, Y. A.; Liu, P.; Zhang, Q.; Xiong, Z. Q.; Shi, X. J.; Wu, L. H.; Shi, W. Q.; Tian, K.; Zhong, X. H.; Shi, K.; Tang, Q. Y.; Zhang, L. J.; Huang, J. L.; He, C. E.; Kuang, F. H.; Zhu, B.; Liu, H.; Jin, X.; Xin, Y. J.; Shi, X. K.; Du, E. Z.; Dore, A. J.; Tang, S.; Collett, J. L., Jr.; Goulding, K.; Zhang, F. S.; Liu, X. J.

    2015-07-01

    Global reactive nitrogen (Nr) deposition to terrestrial ecosystems has increased dramatically since the industrial revolution. This is especially true in recent decades in China due to continuous economic growth. However, there are no comprehensive reports of both measured dry and wet Nr deposition across China. We therefore conducted a multiple-year study during the period mainly from 2010 to 2014 to monitor atmospheric concentrations of five major Nr species of gaseous NH3, NO2 and HNO3, and inorganic nitrogen (NH4+ and NO3-) in both particles and precipitation, based on a Nationwide Nitrogen Deposition Monitoring Network (NNDMN, covering 43 sites) in China. Wet deposition fluxes of Nr species were measured directly; dry deposition fluxes were estimated using airborne concentration measurements and inferential models. Our observations reveal large spatial variations of atmospheric Nr concentrations and dry and wet Nr deposition. The annual average concentrations (1.3-47.0 μg N m-3) and dry plus wet deposition fluxes (2.9-75.2 kg N ha-1 yr-1) of inorganic Nr species ranked by region as North China > Southeast China > Southwest China > Northeast China > Northwest China > the Tibetan Plateau or by land use as urban > rural > background sites, reflecting the impact of anthropogenic Nr emission. Average dry and wet N deposition fluxes were 18.5 and 19.3 kg N ha-1 yr-1, respectively, across China, with reduced N deposition dominating both dry and wet deposition. Our results suggest atmospheric dry N deposition is equally important to wet N deposition at the national scale and both deposition forms should be included when considering the impacts of N deposition on environment and ecosystem health.

  7. Quantifying atmospheric nitrogen deposition through a nationwide monitoring network across China

    Directory of Open Access Journals (Sweden)

    W. Xu

    2015-07-01

    Full Text Available Global reactive nitrogen (Nr deposition to terrestrial ecosystems has increased dramatically since the industrial revolution. This is especially true in recent decades in China due to continuous economic growth. However, there are no comprehensive reports of both measured dry and wet Nr deposition across China. We therefore conducted a multiple-year study during the period mainly from 2010 to 2014 to monitor atmospheric concentrations of five major Nr species of gaseous NH3, NO2 and HNO3, and inorganic nitrogen (NH4+ and NO3− in both particles and precipitation, based on a Nationwide Nitrogen Deposition Monitoring Network (NNDMN, covering 43 sites in China. Wet deposition fluxes of Nr species were measured directly; dry deposition fluxes were estimated using airborne concentration measurements and inferential models. Our observations reveal large spatial variations of atmospheric Nr concentrations and dry and wet Nr deposition. The annual average concentrations (1.3–47.0 μg N m−3 and dry plus wet deposition fluxes (2.9–75.2 kg N ha−1 yr−1 of inorganic Nr species ranked by region as North China > Southeast China > Southwest China > Northeast China > Northwest China > the Tibetan Plateau or by land use as urban > rural > background sites, reflecting the impact of anthropogenic Nr emission. Average dry and wet N deposition fluxes were 18.5 and 19.3 kg N ha−1 yr−1, respectively, across China, with reduced N deposition dominating both dry and wet deposition. Our results suggest atmospheric dry N deposition is equally important to wet N deposition at the national scale and both deposition forms should be included when considering the impacts of N deposition on environment and ecosystem health.

  8. A Heavy Metal Atmospheric Deposition Study in the South Ural Mountains

    CERN Document Server

    Frontasyeva, M V; Steinnes, E; Lyapunov, S M; Cherchintsev, V D

    2002-01-01

    Samples of the mosses Hylocomium splendens and Pleurozium schreberi, collected in the summer of 1998, were used to study the atmospheric deposition of heavy metals and other toxic elements in the Chelyabinsk Region situated in the South Ural, one of the most heavily polluted industrial areas of the Russian Federation. Samples of natural soils were collected simultaneously with moss at the same 30 sites in order to investigate surface accumulation of heavy metals and to examine the correlation of elements in moss and soil samples in order to separate contributions from atmospheric deposition and from soil minerals. A total of 38 elements (Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Rb, Sr, Zr, Mo, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Yb, Hf, Ta, W, Au, Th, U) in soil and 33 elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Ag, Sb, Cs, Ba, La, Ce, Sm, Tb, Yb, Hf, Ta, W, Au, Th, U) in mosses were determined by epithermal neutron activation analysis. The elem...

  9. A global assessment of forest surface albedo and its relationships with climate and atmospheric nitrogen deposition.

    Science.gov (United States)

    Leonardi, Stefano; Magnani, Federico; Nolè, Angelo; Van Noije, Twan; Borghetti, Marco

    2015-01-01

    We present a global assessment of the relationships between the short-wave surface albedo of forests, derived from the MODIS satellite instrument product at 0.5° spatial resolution, with simulated atmospheric nitrogen deposition rates (Ndep ), and climatic variables (mean annual temperature Tm and total annual precipitation P), compiled at the same spatial resolution. The analysis was performed on the following five forest plant functional types (PFTs): evergreen needle-leaf forests (ENF); evergreen broad-leaf forests (EBF); deciduous needle-leaf forests (DNF); deciduous broad-leaf forests (DBF); and mixed-forests (MF). Generalized additive models (GAMs) were applied in the exploratory analysis to assess the functional nature of short-wave surface albedo relations to environmental variables. The analysis showed evident correlations of albedo with environmental predictors when data were pooled across PFTs: Tm and Ndep displayed a positive relationship with forest albedo, while a negative relationship was detected with P. These correlations are primarily due to surface albedo differences between conifer and broad-leaf species, and different species geographical distributions. However, the analysis performed within individual PFTs, strengthened by attempts to select 'pure' pixels in terms of species composition, showed significant correlations with annual precipitation and nitrogen deposition, pointing toward the potential effect of environmental variables on forest surface albedo at the ecosystem level. Overall, our global assessment emphasizes the importance of elucidating the ecological mechanisms that link environmental conditions and forest canopy properties for an improved parameterization of surface albedo in climate models. PMID:25044609

  10. Biogeochemical context impacts seawater pH changes resulting from atmospheric sulfur and nitrogen deposition

    NARCIS (Netherlands)

    Hagens, M.; Hunter, K.A.; Liss, P.S.; Middelburg, J.J.

    2014-01-01

    Seawater acidification can be induced both by absorption of atmospheric carbon dioxide (CO2) and by atmospheric deposition of sulfur and nitrogen oxides and ammonia. Their relative significance, interplay, and dependency on water column biogeochemistry are not well understood. Using a simple biogeoc

  11. Dissolved organic nitrogen dominates in European bogs under increasing atmospheric N deposition

    NARCIS (Netherlands)

    Bragazza, L.; Limpens, J.

    2004-01-01

    To assess the effects of increased atmospheric N input on N availability in ombrotrophic peatlands, the relative concentrations of dissolved organic nitrogen (DON) to dissolved inorganic nitrogen (DIN) were measured in bog waters along a natural gradient of atmospheric N deposition. Six European bog

  12. External quality-assurance results for the National Atmospheric Deposition Program / National Trends Network and Mercury Deposition Network, 2004

    Science.gov (United States)

    Wetherbee, Gregory A.; Latysh, Natalie E.; Greene, Shannon M.

    2006-01-01

    The U.S. Geological Survey (USGS) used five programs to provide external quality-assurance monitoring for the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) and two programs to provide external quality-assurance monitoring for the NADP/Mercury Deposition Network (NADP/MDN) during 2004. An intersite-comparison program was used to estimate accuracy and precision of field-measured pH and specific-conductance. The variability and bias of NADP/NTN data attributed to field exposure, sample handling and shipping, and laboratory chemical analysis were estimated using the sample-handling evaluation (SHE), field-audit, and interlaboratory-comparison programs. Overall variability of NADP/NTN data was estimated using a collocated-sampler program. Variability and bias of NADP/MDN data attributed to field exposure, sample handling and shipping, and laboratory chemical analysis were estimated using a system-blank program and an interlaboratory-comparison program. In two intersite-comparison studies, approximately 89 percent of NADP/NTN site operators met the pH measurement accuracy goals, and 94.7 to 97.1 percent of NADP/NTN site operators met the accuracy goals for specific conductance. Field chemistry measurements were discontinued by NADP at the end of 2004. As a result, the USGS intersite-comparison program also was discontinued at the end of 2004. Variability and bias in NADP/NTN data due to sample handling and shipping were estimated from paired-sample concentration differences and specific conductance differences obtained for the SHE program. Median absolute errors (MAEs) equal to less than 3 percent were indicated for all measured analytes except potassium and hydrogen ion. Positive bias was indicated for most of the measured analytes except for calcium, hydrogen ion and specific conductance. Negative bias for hydrogen ion and specific conductance indicated loss of hydrogen ion and decreased specific conductance from contact of the sample with

  13. Observations of atmospheric Hg species and depositions in remote areas of China

    OpenAIRE

    Feng X; Fu X.; Zhang H.

    2013-01-01

    From September 2007, we conducted continuous measurements of speciated atmospheric mercury (Hg) and atmospheric mercury depositions at five remote sites in China. Four of these sites were involved in the Global Mercury Observation System (GMOS) as ground-based stations. These stations were located in the northwest, southwest, northeast, and east part of China, respectively, which represent the regional atmospheric Hg budgets in different areas of China. The preliminary results showed that mea...

  14. Subalpine grassland carbon balance during 7 years of increased atmospheric N deposition

    OpenAIRE

    Volk, Matthias; Enderle, Jan; Bassin, Seraina

    2016-01-01

    Air pollution agents interact when affecting biological sinks for atmospheric CO2, e.g., the soil organic carbon (SOC) content of grassland ecosystems. Factors favoring plant productivity, like atmospheric N deposition, are usually considered to favor SOC storage. In a 7-year experiment in subalpine grassland under N- and O3-deposition treatment, we examined C fluxes and pools. Total N deposition was 4, 9, 14, 29 and 54 kg N ha−1 yr−1 (N4, N9, etc.); annual mean phytotoxic ...

  15. Atmospheric deposition of {sup 137}Cs between 1994 and 2002 at Cienfuegos, Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Alonso-Hernandez, C.M. [Centro de Estudios Ambientales de Cienfuegos, AP 5. Ciudad Nuclear, Cienfuegos (Cuba)]. E-mail: carlos@ceac.perla.inf.cu; Cartas-Aguila, H. [Centro de Estudios Ambientales de Cienfuegos, AP 5. Ciudad Nuclear, Cienfuegos (Cuba); Diaz-Asencio, M. [Centro de Estudios Ambientales de Cienfuegos, AP 5. Ciudad Nuclear, Cienfuegos (Cuba); Munoz-Caravaca, A. [Centro de Estudios Ambientales de Cienfuegos, AP 5. Ciudad Nuclear, Cienfuegos (Cuba); Martin-Perez, J. [Centro de Estudios Ambientales de Cienfuegos, AP 5. Ciudad Nuclear, Cienfuegos (Cuba); Sibello-Hernandez, R. [Centro de Estudios Ambientales de Cienfuegos, AP 5. Ciudad Nuclear, Cienfuegos (Cuba)

    2006-07-01

    Levels of {sup 137}Cs in total atmospheric deposition have been measured in the Cienfuegos region (Cuba) between 1994 and 2002. Samples were collected every three months, evaporated to dryness to obtain residual samples, and measured by gamma spectrometry. The {sup 137}Cs mean concentration in total deposition was 0.24 Bq m{sup -2} and data ranged between <0.05 and 0.62 Bq m{sup -2}. Precipitation rates and raintime have proved to be the most important factors controlling the concentration and depositional flux of {sup 137}Cs in the atmosphere over Cienfuegos, showing a high correlation coefficient (R = 0.93)

  16. Dry deposition of submicron atmospheric aerosol over water surfaces in motion

    International Nuclear Information System (INIS)

    Whether by chronic or accidental releases, the impact of a nuclear installation on the environment mainly depends on atmospheric transfers; and as the accidents at Chernobyl and Fukushima show, affect the contamination of surfaces and impacts in the medium and long-term on the environment and the population. In this context, this work focuses on the characterization and modeling of dry deposition of submicron aerosols on liquid surfaces in motion such as rivers. Unlike wet deposition which is conditioned by washout and rainout (rain and clouds), dry deposition is a phenomenon that depends entirely on the characteristics of aerosols, receiving surfaces, and air flow. In practice, the evaluation of dry deposition is based on the estimation of flux modeling as the product of particle concentration and deposition velocity which can vary over several orders of magnitude depending on the receiving surfaces (forest, snow, urban, grassland..). This topic is motivated by the virtual non-existence of studies on the mechanisms of dry deposition on continental water systems such as rivers; and respect for submicron aerosols. They have the lowest deposition efficiencies and filtration and the longer residence time in the atmosphere. In addition, they are potentially the most dangerous to living beings because they can penetrate deeper into the airway. Due to the lack of data on the dry deposition of submicron aerosols on a liquid surface in motion, the approach was based on two axes: 1) the acquisition of experimental deposition velocities and 2) the analysis and interpretation of results through modeling. The experiments were performed with uranine aerosols released into the IOA wind tunnel (Interface Ocean Atmosphere) of the Institute for Research on Non Equilibrium Phenomena which is configured to study the coupling between the air flow and water. These experiments have given many dry deposition velocities for different configurations characterized according to wind

  17. Atmospheric deposition of semivolatile organic compounds to plants

    NARCIS (Netherlands)

    Bakker, Martine Inez

    2001-01-01

    This thesis describes how the deposition of semivolatile organic compounds (SOCs) to plant surfaces is affected by the characteristics of the plant. From a literature review, it was concluded that differences between SOC concentrations in different plant species are often very small (< a factor o

  18. Atmospheric Electric Fields and Radon Daughter Deposition on Vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Jeffers, D

    1999-07-01

    Porstendoerfer has reported deposition velocities of unattached radon daughters measured above a growing wheat canopy which are ten times the values measured in a wind tunnel. It is suggested that this is the consequence of the enhancement of the natural electric field at the tips of the ears of wheat. (author)

  19. Thermodynamic analysis and deposition of refractory materials

    International Nuclear Information System (INIS)

    This article does not pretend to be an exhaustive review of all publications in which a thermodynamic analysis has been used to analyse the chemical vapour deposition of refractory materials. It simply covers a certain number of experiments in which the present authors made use of various aspects of this method: overall or partial optimization of a process, determination of the deposition material most suited to fulfilling a given role and approach to mechanisms governing the chemical deposition reaction. A thermodynamic analysis is presented here from a more unusual angle, by examples of localized and varied intervention, in order to demonstrate the multiple uses of the method. (orig.)

  20. NATIONAL ATMOSPHERIC DEPOSITION PROGRAM (NADP), 4 NC SITES

    Science.gov (United States)

    National Atmospheric Depostion Program (NADP) data for 4 sites in North Carolina - those within or in close proximity to the Albemarle-Pamlico Estuary watershed. No Virginia sites are within this watershed. See included text files for file contents. Separate directories for each ...

  1. Potential geographic distribution of atmospheric nitrogen deposition from intensive livestock production in North Carolina, USA

    Energy Technology Data Exchange (ETDEWEB)

    Costanza, Jennifer K. [Curriculum in Ecology, University of North Carolina at Chapel Hill, Campus Box 3275, Chapel Hill, NC 27599-3275 (United States)], E-mail: costanza@unc.edu; Marcinko, Sarah E. [Curriculum in Ecology, University of North Carolina at Chapel Hill, Campus Box 3275, Chapel Hill, NC 27599-3275 (United States); Goewert, Ann E. [Department of Geological Sciences, Campus Box 3315, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3315 (United States); Mitchell, Charles E. [Curriculum in Ecology, University of North Carolina at Chapel Hill, Campus Box 3275, Chapel Hill, NC 27599-3275 (United States)

    2008-07-15

    To examine the consequences of increased spatial aggregation of livestock production facilities, we estimated the annual production of nitrogen in livestock waste in North Carolina, USA, and analyzed the potential distribution of atmospheric nitrogen deposition from confined animal feeding operations ('CAFO') lagoons. North Carolina is a national center for industrial livestock production. Livestock is increasingly being raised in CAFOs, where waste is frequently held, essentially untreated, in open-air lagoons. Reduced nitrogen in lagoons is volatilized as ammonia (NH{sub 3}), transported atmospherically, and deposited to other ecosystems. The Albemarle-Pamlico Sound, NC, is representative of nitrogen-sensitive coastal waters, and is a major component of the second largest estuarine complex in the U.S. We used GIS to model the area of water in the Sound within deposition range of CAFOs. We also evaluated the number of lagoons within deposition range of each 1 km{sup 2} grid cell of the state. We considered multiple scenarios of atmospheric transport by varying distance and directionality. Modeled nitrogen deposition rates were particularly elevated for the Coastal Plain. This pattern matches empirical data, suggesting that observed regional patterns of reduced nitrogen deposition can be largely explained by two factors: limited atmospheric transport distance, and spatial aggregation of CAFOs. Under our medium-distance scenario, a small portion (roughly 22%) of livestock production facilities contributes disproportionately to atmospheric deposition of nitrogen to the Albemarle-Pamlico Sound. Furthermore, we estimated that between 14-37% of the state receives 50% of the state's atmospheric nitrogen deposition from CAFO lagoons. The estimated total emission from livestock is 134,000 t NH{sub 3} yr{sup -1}, 73% of which originates from the Coastal Plain. Stronger waste management and emission standards for CAFOs, particularly those on the Coastal Plain

  2. Improved mapping of National Atmospheric Deposition Program wet-deposition in complex terrain using PRISM-gridded data sets

    Science.gov (United States)

    Latysh, Natalie E.; Wetherbee, Gregory Alan

    2012-01-01

    High-elevation regions in the United States lack detailed atmospheric wet-deposition data. The National Atmospheric Deposition Program/National Trends Network (NADP/NTN) measures and reports precipitation amounts and chemical constituent concentration and deposition data for the United States on annual isopleth maps using inverse distance weighted (IDW) interpolation methods. This interpolation for unsampled areas does not account for topographic influences. Therefore, NADP/NTN isopleth maps lack detail and potentially underestimate wet deposition in high-elevation regions. The NADP/NTN wet-deposition maps may be improved using precipitation grids generated by other networks. The Parameter-elevation Regressions on Independent Slopes Model (PRISM) produces digital grids of precipitation estimates from many precipitation-monitoring networks and incorporates influences of topographical and geographical features. Because NADP/NTN ion concentrations do not vary with elevation as much as precipitation depths, PRISM is used with unadjusted NADP/NTN data in this paper to calculate ion wet deposition in complex terrain to yield more accurate and detailed isopleth deposition maps in complex terrain. PRISM precipitation estimates generally exceed NADP/NTN precipitation estimates for coastal and mountainous regions in the western United States. NADP/NTN precipitation estimates generally exceed PRISM precipitation estimates for leeward mountainous regions in Washington, Oregon, and Nevada, where abrupt changes in precipitation depths induced by topography are not depicted by IDW interpolation. PRISM-based deposition estimates for nitrate can exceed NADP/NTN estimates by more than 100% for mountainous regions in the western United States.

  3. Atmospheric pressure chemical vapor deposition of ZnO: Process modeling and experiments

    International Nuclear Information System (INIS)

    The deposition of zinc oxide has been performed by atmospheric pressure chemical vapor deposition and trends in growth rates are compared with the literature. Diethylzinc and tertiary butanol were used as the primary reactants and deposition rates above 800 nm/min were obtained. The reaction kinetics were studied and detailed process modeling based on a reaction mechanism that includes the formation of an alkylzinc alkoxide intermediate product is discussed. This mechanism can explain the temperature dependent variety in deposition profiles observed in the static deposition experiments. The capability of modeling to gain insight in the local process conditions inside a reactor is demonstrated. - Highlights: • ZnO deposition at high rates of 800 nm/min • Modeling based on two step mechanism gives good fit. • Modeling gives insight in the inside of the reactor. • Modeling can even predict static deposition profiles

  4. Correlation of atmospheric deposition and diseases in the Euroregion Neisse

    International Nuclear Information System (INIS)

    A biomonitoring system using the mosses Pleurozium schreberi and Polytrichum formosum as biomonitors has been used to determine the degree of pollution in the Euroregion Neisse (ERN). This region, located in Central Europe where the borders Germany, Poland and Czech Republic meet, was one of the most highly polluted areas in Europe until the early 1990s. For clarity and ease of access the results have been presented visually using a Geographical Information System (GIS) (Markert et al., 1999; Wappelhorst, 1999; Wappelhorst et al., 1999). The deposition of 37 elements in the Euroregion as found in the moss study is compared with the incidence of various diseases, using data from regional hospitals. Connections between diseases of the respiratory tract and Ce, Fe, Ga and Ge deposition as well as between cardiovascular diseases and Tl were determined. The results will be validated by further studies with an even greater amount of data. (author)

  5. Distribution of atmospheric marine salt depositions over Continental Western Europe

    OpenAIRE

    Delalieux, F.; van Grieken, R.; Potgieter, J. H.

    2006-01-01

    This contribution describes the distribution of marine salt aerosols in Belgium, France and Spain, as obtained from applying a kriging model to a set of data. The data was collected over a period of nine years and included wet as well as dry deposition results. It was found that the concentration of the salt particles decreased the fastest in Spain and the slowest in Belgium with increasing inland distance from the sea. These findings have implications for the degradation of monuments and his...

  6. The watershed depositon tool : a tool for incorporating atmospheric deposition in water-quality analyses {sup 1}.

    Energy Technology Data Exchange (ETDEWEB)

    Schwede, D. B.; Dennis, R. L.; Bitz, M. A.; Decision and Information Sciences; NOAA; EPA

    2009-08-01

    A tool for providing the linkage between air and water-quality modeling needed for determining the Total Maximum Daily Load (TMDL) and for analyzing related nonpoint-source impacts on watersheds has been developed. Using gridded output of atmospheric deposition from the Community Multiscale Air Quality (CMAQ) model, the Watershed Deposition Tool (WDT) calculates average per unit area and total deposition to selected watersheds and subwatersheds. CMAQ estimates the wet and dry deposition for all of its gaseous and particulate chemical species, including ozone, sulfur species, nitrogen species, secondary organic aerosols, and hazardous air pollutants at grid scale sizes ranging from 4 to 36 km. An overview of the CMAQ model is provided. The somewhat specialized format of the CMAQ files is not easily imported into standard spatial analysis tools. The WDT provides a graphical user interface that allows users to visualize CMAQ gridded data and perform further analyses on selected watersheds or simply convert CMAQ gridded data to a shapefile for use in other programs. Shapefiles for the 8-digit (cataloging unit) hydrologic unit code polygons for the United States are provided with the WDT; however, other user-supplied closed polygons may be used. An example application of the WDT for assessing the contributions of different source categories to deposition estimates, the contributions of wet and dry deposition to total deposition, and the potential reductions in total nitrogen deposition to the Albemarle-Pamlico basin stemming from future air emissions reductions is used to illustrate the WDT capabilities.

  7. Thaumasite formation in hydraulic mortars by atmospheric SO^ deposition

    OpenAIRE

    Blanco-Varela, María Teresa; Martínez-Ramírez, S.; Sabbioni, C.; Zappia, G.; Toumbakari, E. E.; Aguilera, J.; Palomo, Ángel; Riontino, C.; Van Valen, K.

    2001-01-01

    [EN]Sulphation of mortars and concretes is a function of diverse environmental factors (SO^ aerosol, temperature, etc) as well as some material characteristics. One of the phases that could be formed as consequence of the sulphation of the hydraulic binder is thaumasite. In this paper different hydraulic mortars have been exposed to laboratory exposure chambers in order to reproduce thaumasite formation due to atmospheric SO^. Under the laboratory exposure conditions, ...

  8. Environmental consequences of uranium atmospheric releases from fuel cycle facility: II. The atmospheric deposition of uranium and thorium on plants

    International Nuclear Information System (INIS)

    Uranium and thorium isotopes were measured in cypress leaves, wheat grains and lettuce taken in the surroundings of the uranium conversion facility of Malvési (South of France). The comparison of activity levels and activity ratios (namely 238U/232Th and 230Th/232Th) in plants with those in aerosols taken at this site and plants taken far from it shows that aerosols emitted by the nuclear site (uranium releases in the atmosphere by stacks and 230Th-rich particles emitted from artificial ponds collecting radioactive waste mud) accounts for the high activities recorded in the plant samples close to the site. The atmospheric deposition process onto the plants appears to be the dominant process in plant contamination. Dry deposition velocities of airborne uranium and thorium were measured as 4.6 × 10−3 and 5.0 × 10−3 m s−1, respectively. - Highlights: • Uranium and thorium were measured in plants near the uranium conversion facility. • Activity ratios show that emissions account for the high activities recorded in the plants. • The atmospheric deposition process appears to dominate in plant contamination. • Dry deposition velocities of airborne uranium and thorium were determined

  9. Saharan versus local influence on atmospheric aerosol deposition in the southern Iberian Peninsula: Significance for N and P inputs

    Science.gov (United States)

    Morales-Baquero, Rafael; Pérez-Martínez, Carmen

    2016-03-01

    A novel methodology was used to evaluate the contribution of Saharan dust to the atmospheric deposition of particulate material (PM), total phosphorus (TP), and total nitrogen (TN) in the southeastern Iberian Peninsula. Dry and wet aerosol depositions were measured weekly during two 1 year periods at one site and simultaneously during spring-summer of the same years at two other sites (intersite distance of ~ 40 km). Statistical relationships among depositions at the different sites permitted differentiation of Saharan dust inputs from locally derived dust. PM and TP depositions were synchronous among the three study sites; the synchrony was elevated during periods of Saharan intrusions (evaluated by air mass retrotrajectories analyses), but no temporal correlation was observed during periods without Saharan intrusions. According to analysis of variance results, PM and TP depositions were both significantly affected by Saharan intrusions. During weeks with Saharan intrusions, PM deposition increased around 85% above background levels, with no differences among the three sites, while TP deposition increased by 1.1 µmol TP m-2 d-1, i.e., 29% to 81% above background levels depending on the site. There were no correlations or differences in TN deposition among sites or as a function of Saharan intrusion periods. The annual contribution of PM and TP from Saharan dust was 75 kg ha-1 and 0.07 kg P ha-1, respectively, which can be considered a genuine input for the ecosystems in this area. This novel approach is likely to be valid in any area in the world under atmospheric deposition of long-range transported material.

  10. LEAF WASHING AS AN ASSESSMENT TOOL TO CHARACTERIZE DRY ATMOSPHERIC DEPOSITION

    Directory of Open Access Journals (Sweden)

    Livia Vittori Antisari

    2012-12-01

    Full Text Available The aim of this work was to characterize dry atmospheric deposition after the washing of broad leaves and conifer foliage. To assess this method different sites chosen on the basis of different exposure to both point (e.g. waste incinerator plant (WIP, local crafts and widespread (e.g. roads, agricultural practices sources of anthropogenic pollution.The principal components analysis (PCA, performed on the major and trace elements identified after leaf washing, extracted four factors. F2 was lithogenic while the other three were anthropogenic. The enrichment factor (EF highlights that Cd, Cu and Zn had a purely anthropogenic origin. The sites were grouped according to the predominant source of exposure and the synthetic index of enrichment (SIE showed a decrease as follows: downwind from WIP > max exposure to WIP > min exposure to WIP > road > craft > rural zone.The leaf area allows to calculate the annual flow of elements and the deposition flux in the study area varied for Cd from 0.07 to 0.55 mg m-2, for Co from 0.1 to 0.48 mg m-2, for Cr from 0.63 to 3.7 mg m-2, for Cu from 14.5 to 32.27 mg m-2. The Cd flux in the Bologna area was lower than in some industrial zones of the World and the lowest values were found in the rural zones and under a minimum exposure to the incinerator plant, while the highest values were near the roads and under maximum exposure to the incinerator. The direct analysis of the leaf-washing water allows to discriminate the anthropogenic or geogenic metals deposited on the leaves using multivariate statistical analysis. It is also possible to predict the flow of metals in different areas of investigation.

  11. Current state and temporal evolution of the chemical composition of atmospheric depositions in forest areas of the CONECOFOR network

    Directory of Open Access Journals (Sweden)

    Marchetto A

    2014-04-01

    Full Text Available Current state and temporal evolution of the chemical composition of atmospheric depositions in forest areas of the CONECOFOR network. Since 1997, atmospheric deposition was sampled and analyzed in the permanent plots of the Italian network for the evaluation of forest health (CONECOFOR, under the coordination of the Italian Forest Service. This paper presents the results of the activity carried out in 2009, when the EU-funded LIFE+ “FutMon” project allowed to extend the sampling network to 22 sites. Long-term trends will also be evaluated for the sampling sites with the longest time series. The sampling of open field bulk deposition was performed in a clearance close to the CONECOFOR permanent plots, while throughfall deposition and stemflow (in beech stand, only were sampled in the plot. Deposition samples were collected weekly and sent to the laboratories, where they were analyzed for pH, conductivity, major ions, and total carbon and nitrogen. Most measured variables showed a strong geographical gradient. For example, nitrogen deposition was relatively high in the Po plain (where the emissions of nitrogen oxides and ammonia are the highest and surrounding hills, reaching 10-20 kgN ha-1 y-1 in the open field and 13-25 kgN ha-1 y-1 in the throughfall. Sulphate deposition also showed a marked geographical gradient. Deposition of marine aerosol also had an important impact on the chemical composition of atmospheric deposition in Italy, together with the episodic deposition of Saharan dust, which showed a marked gradient, with highest values in the southernmost plots. Trend analysis was carried out on 10 sites running since the beginning of the program. A general negative trend in sulphate concentration was detected, paralleled in most plots by a positive trend in deposition pH, in good agreement with the strong reduction in the emission of sulphur dioxide recorded in the last decades. Nitrogen concentration also showed a significant decrease

  12. Wet and dry atmospheric depositions of inorganic nitrogen during plant growing season in the coastal zone of Yellow River Delta.

    Science.gov (United States)

    Yu, Junbao; Ning, Kai; Li, Yunzhao; Du, Siyao; Han, Guangxuan; Xing, Qinghui; Wu, Huifeng; Wang, Guangmei; Gao, Yongjun

    2014-01-01

    The ecological problems caused by dry and wet deposition of atmospheric nitrogen have been widespread concern in the world. In this study, wet and dry atmospheric depositions were monitored in plant growing season in the coastal zone of the Yellow River Delta (YRD) using automatic sampling equipment. The results showed that SO4 (2-) and Na(+) were the predominant anion and cation, respectively, in both wet and dry atmospheric depositions. The total atmospheric nitrogen deposition was ~2264.24 mg m(-2), in which dry atmospheric nitrogen deposition was about 32.02%. The highest values of dry and wet atmospheric nitrogen deposition appeared in May and August, respectively. In the studied area, NO3 (-)-N was the main nitrogen form in dry deposition, while the predominant nitrogen in wet atmospheric deposition was NH4 (+)-N with ~56.51% of total wet atmospheric nitrogen deposition. The average monthly attribution rate of atmospheric deposition of NO3 (-)-N and NH4 (+)-N was ~31.38% and ~20.50% for the contents of NO3 (-)-N and NH4 (+)-N in 0-10 cm soil layer, respectively, suggested that the atmospheric nitrogen was one of main sources for soil nitrogen in coastal zone of the YRD. PMID:24977238

  13. Wet and Dry Atmospheric Depositions of Inorganic Nitrogen during Plant Growing Season in the Coastal Zone of Yellow River Delta

    Directory of Open Access Journals (Sweden)

    Junbao Yu

    2014-01-01

    Full Text Available The ecological problems caused by dry and wet deposition of atmospheric nitrogen have been widespread concern in the world. In this study, wet and dry atmospheric depositions were monitored in plant growing season in the coastal zone of the Yellow River Delta (YRD using automatic sampling equipment. The results showed that SO42- and Na+ were the predominant anion and cation, respectively, in both wet and dry atmospheric depositions. The total atmospheric nitrogen deposition was ~2264.24 mg m−2, in which dry atmospheric nitrogen deposition was about 32.02%. The highest values of dry and wet atmospheric nitrogen deposition appeared in May and August, respectively. In the studied area, NO3-–N was the main nitrogen form in dry deposition, while the predominant nitrogen in wet atmospheric deposition was NH4+–N with ~56.51% of total wet atmospheric nitrogen deposition. The average monthly attribution rate of atmospheric deposition of NO3-–N and NH4+–N was ~31.38% and ~20.50% for the contents of NO3-–N and NH4+–N in 0–10 cm soil layer, respectively, suggested that the atmospheric nitrogen was one of main sources for soil nitrogen in coastal zone of the YRD.

  14. Human - driven atmospheric deposition of N & P controls on the East Mediterranean marine ecosystem

    Science.gov (United States)

    Christodoulaki, Sylvia; Petihakis, George; Mihalopoulos, Nikolaos; Tsiaras, Konstantinos; Triantafyllou, George; Kanakidou, Maria

    2016-04-01

    The historical and future impacts of atmospheric deposition of inorganic nitrogen (N) and phosphorus (P) on the marine ecosystem in the East Mediterranean Sea are investigated by using a 1-D coupled physical- biogeochemical model, set-up for the Cretan Sea as a representative area of the basin. For the present-day simulation (2010), the model is forced by observations of atmospheric deposition fluxes at Crete, while for the hindcast (1860) and forecast (2030) simulations, the changes in atmospheric deposition calculated by global chemistry- transport models are applied to the present-day observed fluxes. The impact of the atmospheric deposition on the fluxes of carbon in the food chain is calculated together with the contribution of human activities to these impacts. The results show that total phytoplanktonic biomass increased by 16% over the past 1.5 century. Small fractional changes in carbon fluxes and planktonic biomasses are predicted for the near future. Simulations show that atmospheric deposition of N and P may be the main mechanism responsible for the anomalous N to P ratio observed in the Mediterranean Sea.

  15. 7Be in atmospheric deposition. Determination of seasonal indices

    International Nuclear Information System (INIS)

    This paper is focused on the results for activity concentrations of 7Be in depositions recorded in Vinca Institute of Nuclear Sciences, as part of radioactivity monitoring in Institute from 1994 to 2013. year. Samples were collected on a monthly basis and activities were present on sampling day (middle of the month). The activities were determined on HPGe detectors by standard gamma spectrometry, and they ranged from 0.05 to 10.4 Bq m-2. The obtained results were statistically analyzed. The 7Be activity shows a pronounced seasonal pattern, with the maximum in spring-summer and minimum in winter. (author)

  16. Atmospheric deposition patterns of 210Pb and 7Be in Cienfuegos, Cuba

    International Nuclear Information System (INIS)

    The radiometric composition of bulk deposition samples, collected monthly for one year, February 2010 until January 2011, at a site located in Cienfuegos (22° 03′ N, 80° 29′ W) (Cuba), are analysed in this paper. Measurement of 7Be and 210Pb activity concentrations were carried out in 12 bulk deposition samples. The atmospheric deposition fluxes of 7Be and 210Pb are in the range of 13.2–132 and 1.24–8.29 Bq m−2, and their mean values are: 56.6 and 3.97 Bq m−2, respectively. The time variations of the different radionuclide have been discussed in relation with meteorological factors and the mean values have been compared to those published in recent literature from other sites located at different latitudes. The annual average flux of 210Pb and 7Be were 47 and 700 Bq m−2 y−1, respectively. Observed seasonal variations of deposition data are explained in terms of different environmental features. The atmospheric deposition fluxes of 7Be and 210Pb were moderately well correlated with precipitation and well correlated with one another. The 210Pb/7Be ratios in the monthly depositions samples varied in the range of 0.05–0.10 and showed a strong correlation with the number of rainy days. - Highlights: • We evaluated for first time in Cuba the atmospheric deposition fluxes of 7Be and 210Pb. • The annual average flux of 210Pb and 7Be were 47 and 700 Bq m−2 y−1, respectively. • The atmospheric deposition fluxes of 7Be and 210Pb are correlated with precipitation. • 7Be and 210Pb present similar removal behaviour from the atmosphere

  17. Natural or anthropogenic? On the origin of atmospheric sulfate deposition in the Andes of southeastern Ecuador

    Directory of Open Access Journals (Sweden)

    S. Makowski Giannoni

    2014-05-01

    Full Text Available Atmospheric sulfur deposition above certain limits can represent a threat to tropical forests, causing nutrient imbalances and mobilizing toxic elements that impact biodiversity and forest productivity. Atmospheric sources of sulfur deposited by precipitation have being roughly identified in only a few lowland tropical forests. Even scarcer are these type of studies in tropical mountain forests, many of them megadiversity hotspots and especially vulnerable to acidic deposition. Here, the topographic complexity and related streamflow condition the origin, type, and intensity of deposition. Furthermore, in regions with a variety of natural and anthropogenic sulfur sources, like active volcanoes and biomass-burning, no source-emission data has been used for determining the contribution of each of them to the deposition. The main goal of the current study is to evaluate sulfate (SO4− deposition by rain and occult precipitation at two topographic locations in a tropical mountain forest of southern Ecuador, and to trace back the deposition to possible emission sources applying back trajectory modeling. To link upwind natural (volcanic and anthropogenic (urban/industrial and biomass-burning sulfur emissions and observed sulfate deposition, we employed state of the art inventory and satellite data, including volcanic passive degassing as well. We conclude that biomass-burning sources generally dominate sulfate deposition at the evaluated sites. Minor sulfate transport occurs during the shifting of the predominant winds to the north and west. Occult precipitation sulfate deposition and likely rain sulfate deposition are mainly linked to biomass-burning emissions from the Amazon lowlands. Volcanic and anthropogenic emissions from the north and west contribute to occult precipitation sulfate deposition at the mountain crest Cerro del Consuelo meteorological station and to rain-deposited sulfate at the upriver mountain-pass El Tiro meteorological station.

  18. Solar Flux Deposition And Heating Rates In Jupiter's Atmosphere

    Science.gov (United States)

    Perez-Hoyos, Santiago; Sánchez-Lavega, A.

    2009-09-01

    We discuss here the solar downward net flux in the 0.25 - 2.5 µm range in the atmosphere of Jupiter and the associated heating rates under a number of vertical cloud structure scenarios focusing in the effect of clouds and hazes. Our numerical model is based in the doubling-adding technique to solve the radiative transfer equation and it includes gas absorption by CH4, NH3 and H2, in addition to Rayleigh scattering by a mixture of H2 plus He. Four paradigmatic Jovian regions have been considered (hot-spots, belts, zones and Polar Regions). The hot-spots are the most transparent regions with downward net fluxes of 2.5±0.5 Wm-2 at the 6 bar level. The maximum solar heating is 0.04±0.01 K/day and occurs above 1 bar. Belts and zones characterization result in a maximum net downward flux of 0.5 Wm-2 at 2 bar and 0.015 Wm-2 at 6 bar. Heating is concentrated in the stratospheric and tropospheric hazes. Finally, Polar Regions are also explored and the results point to a considerable stratospheric heating of 0.04±0.02 K/day. In all, these calculations suggest that the role of the direct solar forcing in the Jovian atmospheric dynamics is limited to the upper 1 - 2 bar of the atmosphere except in the hot-spot areas. Acknowledgments: This work has been funded by Spanish MEC AYA2006-07735 with FEDER support and Grupos Gobierno Vasco IT-464-07.

  19. Modeling of atmospheric iron processing carried by mineral dust and its deposition to ocean

    Science.gov (United States)

    Nickovic, Slobodan; Vukovic, Ana; Vujadinovic, Mirjam

    2014-05-01

    Relatively insoluble iron in dust originating from desert soils increases its solubility after Fe carried by mineral dust is chemically processed by the atmosphere. After dust is deposited deposition to the ocean, soluble Fe as a nutrient could enhance the marine primary production. The atmospheric dust cycle is driven by the atmospheric processes often of smaller, meso-scales. The soil mineralogy of dust emitted from sources determines also how much Fe in the aerosol will be finding. Once Fe is exposed to the atmospheric processes, the atmospheric radiation, clouds and polluted air will chemically affect the iron in dust. Global dust-iron models, having typical horizontal resolutions of 100-300 km which are mostly used to numerically simulate the fate of iron in the atmosphere can provide rather global picture of the dust and iron transport, but not details. Such models often introduce simplistic approximation on the Fe content in dust-productive soils. To simulate the Fe processing we instead implemented a high resolution regional atmospheric dust-iron model with detailed 1km global map for the geographic distribution of Fe content in soil. We also introduced a parameterization of the Fe processing caused by dust mineralogy, cloud processes and solar radiation. We will present results from simulation experiments in order to explore the model capability to reproduce major observed patterns of deposited Fe into the Atlantic cruises.

  20. Historical and current atmospheric deposition to the epilithic lichen Xanthoparmelia in Maricopa County, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Zschau, T.; Getty, S.; Gries, C.; Ameron, Y.; Zambrano, A.; Nash, T.H

    2003-09-01

    Spatial variation of elemental deposition to lichen receptors across Maricopa County, Arizona, USA is documented for 1998 and historical trends relative to 1974 are documented. - Spatial patterns of atmospheric deposition of trace elements to an epilithic lichen were assessed using a spatial grid of 28 field sites in 1998 throughout Maricopa County, Arizona, USA. In addition, samples of Xanthoparmelia spp. from Arizona State University lichen herbarium material (1975-1976) was utilized for a limited number of sites in order to explore temporal trends. The lichen material was cleaned, wet digested and analyzed by ICP-MS for a suite of elemental concentrations [antimony (Sb), cadmium (Cd), cerium (Ce), chromium (Cr), cobalt (Co), copper (Cu), dysprosium (Dy), europium (Eu), gadolinium (Gd), gold (Au), holmium (Ho), lead (Pb), lutetium (Lu), neodymium (Nd), nickel (Ni), palladium (Pd), platinum (Pt), praseodymium (Pr), samarium (Sm), scandium (Sc), silver (Ag), terbium (Tb), thulium (Tm), tin (Sn), uranium (U), ytterbium (Yb), yttrium (Y), and zinc (Zn)]. Cluster analysis and principal component analysis suggest three major factors, which, depending on regional aerosol fractionation, explain most of the variation in elemental signatures: (1) a group of widely distributed rare earth elements (2) a highly homogenous Co, Cr, Ni, and Sc component representing the influence of mafic rocks, and (3) anthropogenic emissions. Elemental concentrations in Maricopa County lichens were generally comparable to those reported for relatively unpolluted areas. Only highly urbanized regions, such as the greater Phoenix Metropolitan Area and the NW corner of the county, exhibited elevated concentrations for Zn, Cu, Pb, and Cd. Lead levels in lichens have fallen over the last 30 years by 71%, while Zn concentrations for some regions have increased by as much as 245%. From the spatial pattern of elemental deposition for Cd, Cu, Ni, Pr, Pb, and Cu, we infer that agriculture, mining

  1. Environmental consequences of uranium atmospheric releases from fuel cycle facility: II. The atmospheric deposition of uranium and thorium on plants.

    Science.gov (United States)

    Pourcelot, L; Masson, O; Renaud, P; Cagnat, X; Boulet, B; Cariou, N; De Vismes-Ott, A

    2015-03-01

    Uranium and thorium isotopes were measured in cypress leaves, wheat grains and lettuce taken in the surroundings of the uranium conversion facility of Malvési (South of France). The comparison of activity levels and activity ratios (namely (238)U/(232)Th and (230)Th/(232)Th) in plants with those in aerosols taken at this site and plants taken far from it shows that aerosols emitted by the nuclear site (uranium releases in the atmosphere by stacks and (230)Th-rich particles emitted from artificial ponds collecting radioactive waste mud) accounts for the high activities recorded in the plant samples close to the site. The atmospheric deposition process onto the plants appears to be the dominant process in plant contamination. Dry deposition velocities of airborne uranium and thorium were measured as 4.6 × 10(-3) and 5.0 × 10(-3) m s(-1), respectively.

  2. Environmental consequences of uranium atmospheric releases from fuel cycle facility: II. The atmospheric deposition of uranium and thorium on plants.

    Science.gov (United States)

    Pourcelot, L; Masson, O; Renaud, P; Cagnat, X; Boulet, B; Cariou, N; De Vismes-Ott, A

    2015-03-01

    Uranium and thorium isotopes were measured in cypress leaves, wheat grains and lettuce taken in the surroundings of the uranium conversion facility of Malvési (South of France). The comparison of activity levels and activity ratios (namely (238)U/(232)Th and (230)Th/(232)Th) in plants with those in aerosols taken at this site and plants taken far from it shows that aerosols emitted by the nuclear site (uranium releases in the atmosphere by stacks and (230)Th-rich particles emitted from artificial ponds collecting radioactive waste mud) accounts for the high activities recorded in the plant samples close to the site. The atmospheric deposition process onto the plants appears to be the dominant process in plant contamination. Dry deposition velocities of airborne uranium and thorium were measured as 4.6 × 10(-3) and 5.0 × 10(-3) m s(-1), respectively. PMID:25500060

  3. Characteristics of atmospheric depositions of ionic and carbonaceous components at remote sites in Japan

    Science.gov (United States)

    Sato, K.; Inomata, Y.; Kajino, M.; Tang, N.; Hayakawa, K.; Hakamata, M.; Morisaki, H.

    2015-12-01

    Atmospheric deposition process is important to evaluate lifetimes and budget of atmospheric components. Deposition amounts of sulfur and nitrogen compounds have been evaluated not only in East Asian region but also worldwide. On the other hand, atmospheric deposition of carbonaceous components including organic carbon (OC), elementary carbon (EC) and Polycyclic Aromatic Hydrocarbons (PAHs) were monitored only at a few sites in Europe, North America and Africa, which will obscure removal process and atmospheric concentration distribution of those components. In this study, ionic and carbonaceous components in precipitation and aerosol are monitored at remote sites in Japan, and the characteristics of atmospheric deposition amounts were evaluated.Field observations have been implemented at the Noto station since November 2013 and the Sado station since May 2011. Wet deposition samples were collected by rain samplers, and dry deposition samples were collected by high volume or low volume aerosol samplers. Concentrations of Cl-, NO3-, SO42-, NH4+, Na+, K+, Mg2+, Ca2+ were measured by ion chromatography, EC and OC by the IMPROVE protocol, and PAHs by HPLC with a fluorescence detector. Wet deposition amounts were calculated as the products of aqueous concentration and precipitation amounts, and dry deposition amounts were as the products of aerosol concentrations and deposition velocity estimated by the Inferential Method.Total (wet and dry) annual deposition amounts of carbonaceous components of NO3-, SO42-, EC, water insoluble OC, Fluoranthene at Noto (Nov. 2013 to Oct. 2014) were 4353.81 mg/m2, 7020.50 mg/m2, 149.84 mg/m2, 1191.09 mg/m2, 28.6 μg/m2, respectively. These amounts are comparable total annual deposition amounts of OC and EC at Sado (May 2011 to Feb. 2012), which were 166.04 mg/m2 and 834.0 mg/m2. Higher deposition amounts of ionic and carbonaceous components were observed, which would be attributable to long range transportation of the East Asian

  4. Atmospheric deposition in coniferous and deciduous tree stands in Poland

    Science.gov (United States)

    Kowalska, Anna; Astel, Aleksander; Boczoń, Andrzej; Polkowska, Żaneta

    2016-05-01

    The objective of this study was to assess the transformation of precipitation in terms of quantity and chemical composition following contact with the crown layer in tree stands with varied species composition, to investigate the effect of four predominant forest-forming species (pine, spruce, beech, and oak) on the amount and composition of precipitation reaching forest soils, and to determine the sources of pollution in atmospheric precipitation in forest areas in Poland. The amount and chemical composition (pH, electric conductivity, alkalinity, and chloride, nitrate, sulfate, phosphate, ammonium, calcium, magnesium, sodium, potassium, iron aluminum, manganese, zinc, copper, total nitrogen, and dissolved organic carbon contents) of atmospheric (bulk, BP) and throughfall (TF) precipitation were studied from January to December 2010 on twelve forest monitoring plots representative of Polish conditions. The study results provided the basis for the determination of the fluxes of pollutants in the forest areas of Poland and allowed the comparison of such fluxes with values provided in the literature for European forest areas. The transformation of precipitation in the canopy was compared for different tree stands. The fluxes of substances in an open field and under canopy were influenced by the location of the plot, including the regional meteorological conditions (precipitation amounts), vicinity of the sea (effect of marine aerosols), and local level of anthropogenic pollution. Differences between the plots were higher in TF than in BP. The impact of the vegetation cover on the chemical composition of precipitation depended on the region of the country and dominant species in a given tree stand. Coniferous species tended to cause acidification of precipitation, whereas deciduous species increased the pH of TF. Pine and oak stands enriched precipitation with components that leached from the canopy (potassium, manganese, magnesium) to a higher degree than spruce and

  5. Atmospheric wet and litterfall mercury deposition at urban and rural sites in China

    Science.gov (United States)

    Fu, Xuewu; Yang, Xu; Lang, Xiaofang; Zhou, Jun; Zhang, Hui; Yu, Ben; Yan, Haiyu; Lin, Che-Jen; Feng, Xinbin

    2016-09-01

    Mercury (Hg) concentrations and deposition fluxes in precipitation and litterfall were measured at multiple sites (six rural sites and an urban site) across a broad geographic area in China. The annual deposition fluxes of Hg in precipitation at rural sites and an urban site were 2.0 to 7.2 and 12.6 ± 6.5 µg m-2 yr-1, respectively. Wet deposition fluxes of Hg at rural sites showed a clear regional difference with elevated deposition fluxes in the subtropical zone, followed by the temporal zone and arid/semi-arid zone. Precipitation depth is the primary influencing factor causing the variation of wet deposition. Hg fluxes through litterfall ranged from 22.8 to 62.8 µg m-2 yr-1, higher than the wet deposition fluxes by a factor of 3.9 to 8.7 and representing approximately 75 % of the total Hg deposition at the forest sites in China. This suggests that uptake of atmospheric Hg by foliage is the dominant pathway to remove atmospheric Hg in forest ecosystems in China. Wet deposition fluxes of Hg at rural sites of China were generally lower compared to those in North America and Europe, possibly due to a combination of lower precipitation depth, lower GOM concentrations in the troposphere and the generally lower cloud base heights at most sites that wash out a smaller amount of GOM and PBM during precipitation events.

  6. Annual input fluxes and source identification of trace elements in atmospheric deposition in Shanxi Basin: the largest coal base in China.

    Science.gov (United States)

    Zhong, Cong; Yang, Zhongfang; Jiang, Wei; Yu, Tao; Hou, Qingye; Li, Desheng; Wang, Jianwu

    2014-11-01

    Industrialization and urbanization have led to a great deterioration of air quality and provoked some serious environmental concerns. One hundred and five samples of atmospheric deposition were analyzed for their concentrations of 13 trace elements (As, Cd, Cu, Fe, Al, Co, Cr, Hg, Mn, Mo, Pb, Se, and Zn) in Shanxi Basin, which includes six isolate basins. The input fluxes of the trace elements in atmospheric deposition were observed and evaluated. Geostatistical analysis (EF, PCA, and CA ) were conducted to determine the spatial distribution, possible sources, and enrichment degrees of trace elements in atmospheric deposition. Fe/Al and K/Al also contribute to identify the sources of atmospheric deposition. The distribution of trace elements in atmospheric deposition was proved to be geographically restricted. The results show that As, Cd, Pb, Zn, and Se mainly come from coal combustion. Fe, Cu, Mn, Hg, and Co originate mainly from interactions between local polluted soils and blowing dust from other places, while the main source of Al, Cr, and Mo are the soil parent materials without pollution. This work provides baseline information to develop policies to control and reduce trace elements, especially toxic elements, from atmospheric deposition. Some exploratory analytical methods applied in this work are also worth considering in similar researches.

  7. Mapping correlations between nitrogen concentrations in atmospheric deposition and mosses for natural landscapes in Europe

    OpenAIRE

    Schroder, Winfried; Pesch, Roland; Schonrock, Simon; Harmens, Harry; Mills, Gina; Fagerli, Hilde

    2014-01-01

    Recent investigations proved that nitrogen (N) concentrations in mosses are primarily determined byatmospheric deposition. The correlations are country- and N compound-specific and agree well withspatial patterns and temporal trends across Europe as a whole and in single European countries. Thisstudy investigates whether correlations between the concentration of N in atmospheric deposition andmosses within the units of an ecological land classification of Europe can be established. To this en...

  8. Nutrient availability and phytoplankton nutrient limitation across a gradient of atmospheric nitrogen deposition

    Science.gov (United States)

    Elser, J.J.; Kyle, M.; Steuer, L.; Nydick, K.R.; Baron, J.S.

    2009-01-01

    Atmospheric nitrogen (N) deposition to lakes and watersheds has been increasing steadily due to various anthropogenic activities. Because such anthropogenic N is widely distributed, even lakes relatively removed from direct human disturbance are potentially impacted. However, the effects of increased atmospheric N deposition on lakes are not well documented, We examined phytoplankton biomass, the absolute and relative abundance of limiting nutrients (N and phosphorus [P]), and phytoplankton nutrient limitation in alpine lakes of the Rocky Mountains of Colorado (USA) receiving elevated (>6 kg N??ha-1??yr-1) or low (atmospheric N deposition. Highdeposition lakes had higher NO3-N and total N concentrations and higher total N : total P ratios. Concentrations of chlorophyll and seston carbon (C) were 2-2.5 times higher in highdeposition relative to low-deposition lakes, while high-deposition lakes also had higher seston C:N and C:P (but not N:P) ratios. Short-term enrichment bioassays indicated a qualitative shift in the nature of phytoplankton nutrient limitation due to N deposition, as highdeposition lakes had an increased frequency of primary P limitation and a decreased frequency and magnitude of response to N and to combined N and P enrichment. Thus elevated atmospheric N deposition appears to have shifted nutrient supply from a relatively balanced but predominantly N-deficient regime to a more consistently P-limited regime in Colorado alpine lakes. This adds to accumulating evidence that sustained N deposition may have important effects on lake phytoplankton communities and plankton-based food webs by shifting the quantitative and qualitative nature of nutrient limitation. ?? 2009 by the Ecological Society of America.

  9. Predicting wetland contamination from atmospheric deposition measurements of pesticides in the Canadian Prairie Pothole region

    Science.gov (United States)

    Messing, Paul G.; Farenhorst, Annemieke; Waite, Don T.; McQueen, D. A. Ross; Sproull, James F.; Humphries, David A.; Thompson, Laura L.

    2011-12-01

    Although it has been suggested that atmospheric deposition alone can result in detectable levels of pesticides in wetlands of the Pairie Pothole Region of Canada, this is the first field study to compare the masses of pesticides entering wetlands by atmospheric deposition with those concentrations of pesticides detected in the water-column of prairie wetlands. Weekly air and bulk deposition samples were collected from May 26th to Sept. 15th, 2008 at the Manitoba Zero Tillage Research Association (MZTRA) Farm, Brandon, Manitoba, with four on-site wetlands (approximate sizes 0.15-0.45 ha) monitored every second week. Twelve pesticides were detected in the air, with MCPA (one of the three pesticides applied on the farm in 2008 in addition to clopyralid and glyphosate), triallate, and γ-HCH being detected every week. Calculations were performed to predict wetland pesticide concentrations based on bulk deposits alone for those pesticides that had detectable concentrations in the bulk deposition samples (in order of the highest total seasonal deposition mass to the lowest): MCPA, glyphosate, 2,4-D, clopyralid, bromoxynil, atrazine, dicamba, metolachlor, and mecoprop. The estimated concentrations were closest to actual concentrations for MCPA (Pearson correlation coefficient's = 0.91 to 0.98; p-values atmospheric deposition was clearly relevant to detections of clopyralid in the wetland water-column. Although the types and levels of pesticides detected in the wetlands of the current study suggest that regional pesticide applications can contribute to pesticide surface water contamination following atmospheric transport and deposition, the greater frequency and concentrations of clopyralid, MCPA, and glyphosate detections in wetlands confirm that on-farm pesticide applications have a greater impact on on-site water quality. Beneficial management practices that reduce application drift, as well as rainfall or snowmelt runoff, will be important measures in reducing

  10. Metal contamination of Ganga River (India) as influenced by atmospheric deposition.

    Science.gov (United States)

    Pandey, J; Shubhashish, K; Pandey, Richa

    2009-08-01

    Metal contamination of Ganga river in relation to atmospheric deposition was investigated. The data revealed that, although Cr and Cu remained below their maximum admissible concentrations, levels of Cd and Pb in mid-stream waters at five out of six stations were higher than their respective maximum admissible concentration. About 62% of water samples contained Ni above its maximum admissible concentration of 20 microg L(-1). Metal concentrations in water showed significant correlation and seasonal synchrony with atmospheric deposition. The study forms the first report on air-driven metal contamination of Ganga and has relevance from human health perspectives.

  11. Metal contamination of Ganga River (India) as influenced by atmospheric deposition.

    Science.gov (United States)

    Pandey, J; Shubhashish, K; Pandey, Richa

    2009-08-01

    Metal contamination of Ganga river in relation to atmospheric deposition was investigated. The data revealed that, although Cr and Cu remained below their maximum admissible concentrations, levels of Cd and Pb in mid-stream waters at five out of six stations were higher than their respective maximum admissible concentration. About 62% of water samples contained Ni above its maximum admissible concentration of 20 microg L(-1). Metal concentrations in water showed significant correlation and seasonal synchrony with atmospheric deposition. The study forms the first report on air-driven metal contamination of Ganga and has relevance from human health perspectives. PMID:19434353

  12. Atmospheric Deposition of Indium in the Northeastern United States: Flux and Historical Trends.

    Science.gov (United States)

    White, Sarah Jane O; Keach, Carrie; Hemond, Harold F

    2015-11-01

    The metal indium is an example of an increasingly important material used in electronics and new energy technologies, whose environmental behavior and toxicity are poorly understood despite increasing evidence of detrimental health impacts and human-induced releases to the environment. In the present work, the history of indium deposition from the atmosphere is reconstructed from its depositional record in an ombrotrophic bog in Massachusetts. A novel freeze-coring technique is used to overcome coring difficulties posed by woody roots and peat compressibility, enabling retrieval of relatively undisturbed peat cores dating back more than a century. Results indicate that long-range atmospheric transport is a significant pathway for the transport of indium, with peak concentrations of 69 ppb and peak fluxes of 1.9 ng/cm2/yr. Atmospheric deposition to the bog began increasing in the late 1800s/early 1900s, and peaked in the early 1970s. A comparison of deposition data with industrial production and emissions estimates suggests that both coal combustion and the smelting of lead, zinc, copper, and tin sulfides are sources of indium to the atmosphere in this region. Deposition appears to have decreased considerably since the 1970s, potentially a visible effect of particulate emissions controls instated in North America during that decade. PMID:26426729

  13. Atmospheric nitrogen deposition budget in a subtropical hydroelectric reservoir (Nam Theun II case study, Lao PDR)

    Science.gov (United States)

    Adon, Marcellin; Galy-Lacaux, Corinne; Serça, Dominique; Guerin, Frederic; Guedant, Pierre; Vonghamsao, Axay; Rode, Wanidaporn

    2016-04-01

    With 490 km² at full level of operation, Nam Theun 2 (NT2) is one of the largest hydro-reservoir in South East Asia. NT2 is a trans-basin hydropower project that diverts water from the Nam Theun river (a Mekong tributary) to the Xe Ban Fai river (another Mekong tributary). Atmospheric deposition is an important source of nitrogen (N), and it has been shown that excessive fluxes of N from the atmosphere has resulted in eutrophication of many coastal waters. A large fraction of atmospheric N input is in the form of inorganic N. This study presents an estimation of the atmospheric inorganic nitrogen budget into the NT2 hydroelectric reservoir based on a two-year monitoring (July 2010 to July 2012) including gas concentrations and precipitation. Dry deposition fluxes are calculated from monthly mean surface measurements of NH3, HNO3 and NO2 concentrations (passive samplers) together with simulated deposition velocities, and wet deposition fluxes from NH4+ and NO3- concentrations in single event rain samples (automated rain sampler). Annual rainfall amount was 2500 and 3160 mm for the two years. The average nitrogen deposition flux is estimated at 1.13 kgN.ha-1.yr-1 from dry processes and 5.52 kgN.ha-1.yr-1 from wet ones, i.e., an average annual total nitrogen flux of 6.6 kgN.ha-1.yr-1 deposited into the NT2 reservoir. The wet deposition contributes to 83% of the total N deposition. The nitrogen deposition budget has been also calculated over the rain tropical forest surrounding the reservoir. Due to higher dry deposition velocities above forested ecosystems, gaseous dry deposition flux is estimated at 4.0 kgN.ha-1.yr-1 leading to a total nitrogen deposition about 9.5 kgN.ha-1.yr-1. This result will be compared to nitrogen deposition in the African equatorial forested ecosystems in the framework of the IDAF program (IGAC-DEBITS-AFrica).

  14. Contributions of atmospheric nitrogen deposition to U.S. estuaries: Summary and conclusions: Chapter 8

    Science.gov (United States)

    Stacey, Paul E.; Greening, Holly; Kremer, James N.; Peterson, David; Tomasko, David A.

    2001-01-01

    A NOAA project was initiated in 1998, with support from the U.S. EPA, to develop state-of-the-art estimates of atmospheric N deposition to estuarine watersheds and water surfaces and its delivery to the estuaries. Work groups were formed to address N deposition rates, indirect (from the watershed) yields from atmospheric and other anthropogenic sources, and direct deposition on the estuarine waterbodies, and to evaluate the levels of uncertainty within the estimates. Watershed N yields were estimated using both a land-use based process approach and a national (SPARROW) model, compared to each other, and compared to estimates of N yield from the literature. The total N yields predicted by the national model were similar to values found in the literature and the land-use derived estimates were consistently higher. Atmospheric N yield estimates were within a similar range for the two approaches, but tended to be higher in the land-use based estimates and were not wellcorrelated. Median atmospheric N yields were around 15% of the total N yield for both groups, but ranged as high as 60% when both direct and indirect deposition were considered. Although not the dominant source of anthropogenic N, atmospheric N is, and will undoubtedly continue to be, an important factor in culturally eutrophied estuarine systems, warranting additional research and management attention.

  15. Impact of atmospheric deposition of As, Cd and Pb on their concentration in carrot and celeriac

    International Nuclear Information System (INIS)

    Root crops, carrot and celeriac, were exposed to atmospheric deposition in a polluted versus reference area. An effect was observed on the As, Cd and Pb concentrations of the leaves and the storage organs. The concentrations in the whole storage organs correlated well with atmospheric deposition, which shows that they even could be used for biomonitoring. Nevertheless, leaves remain much more appropriate. The results revealed also a significant increase of the As and Cd concentration in the consumable part of the storage organs as a function of their atmospheric deposition. As such the experiments allowed deriving regression equations, useful for modeling the atmospheric impact of trace elements on the edible parts of root crops. For Pb, however, there was hardly any significant impact on the inner parts of the storage organs and as such the transfer of Pb in the food chain through root crops can be considered to be negligible. - Highlights: ► This paper is exploring new ideas on biomonitoring. ► Some airborne trace elements are transported to unexposed plant parts. ► Storage organs accumulate also airborne trace elements. ► Biomonitoring is useful to study the transfer of trace elements in the food chain. - Biomonitoring as a tool to study the impact of atmospherically deposited trace elements on the food chain.

  16. Simulations of the impact of high pulse atmospheric deposition events on a low nutrient low chlorophyll (LNLC) marine ecosystem

    Science.gov (United States)

    Christodoulaki, Sylvia; Petihakis, George; Tsiaras, Konstantinos; Triantafyllou, George; Mihalopoulos, Nikolaos; Kanakidou, Maria

    2014-05-01

    Nutrient availability controls ocean productivity and partitioning of carbon between the ocean and atmosphere, mediated by the limiting potential of macro and micronutrients such as N, P, Fe and Si. Atmospheric deposition is a major pathway for nutrient delivery with potential to alter the role of the ocean from a sink to a source of CO2 and vice versa. Mediterranean region is of interest for both its marine and atmospheric environments. Its Sea is one of the world's most oligotrophic regions in terms of both primary productivity and chlorophyll-a concentration. Its atmosphere is a cross road of air masses of distinct origin highly affected by both natural and anthropogenic emissions. These emissions strongly interact in the atmosphere, due to the high photochemical activity in the area, leading to the formation of nutrients such as nitrogen compounds. Dust aerosols from the African continent are also affecting the area and act as carriers of nutrients such as iron and phosphorus. In the Eastern Basin, where nutrient riverine inputs are very low, wet and dry atmospheric inputs of N and P are the main source of new nutrients in the euphotic zone of the open sea, particularly during the stratification period. In the present study, the impact of an intense atmospheric nitrogen and phosphorus deposition pulse event on the marine ecosystem in the East Mediterranean Sea is investigated. This is achieved by coupling atmospheric and sea water observations with a 1-D ocean physical-biogeochemical model, set up for the Cretan Sea as a representative E. Mediterranean open sea area (Christodoulaki et al., 2012, Journal of Marine Systems, doi: 10.1016/j.jmarsys.2012.07.007). Atmospheric deposition measurements of Dissolved Inorganic Phosphorous and Nitrogen are obtained from the station of Finokalia, shown to be a representative background station for atmospheric observations in the area, whereas, oceanographic data are obtained from the M3A station. Analysis of this high pulse

  17. Western Pacific atmospheric nutrient deposition fluxes, their impact on surface ocean productivity

    Science.gov (United States)

    Martino, M.; Hamilton, D.; Baker, A. R.; Jickells, T. D.; Bromley, T.; Nojiri, Y.; Quack, B.; Boyd, P. W.

    2014-07-01

    The atmospheric deposition of both macronutrients and micronutrients plays an important role in driving primary productivity, particularly in the low-latitude ocean. We report aerosol major ion measurements for five ship-based sampling campaigns in the western Pacific from ~25°N to 20°S and compare the results with those from Atlantic meridional transects (~50°N to 50°S) with aerosols collected and analyzed in the same laboratory, allowing full incomparability. We discuss sources of the main nutrient species (nitrogen (N), phosphorus (P), and iron (Fe)) in the aerosols and their stoichiometry. Striking north-south gradients are evident over both basins with the Northern Hemisphere more impacted by terrestrial dust sources and anthropogenic emissions and the North Atlantic apparently more impacted than the North Pacific. We estimate the atmospheric supply rates of these nutrients and the potential impact of the atmospheric deposition on the tropical western Pacific. Our results suggest that the atmospheric deposition is P deficient relative to the needs of the resident phytoplankton. These findings suggest that atmospheric supply of N, Fe, and P increases primary productivity utilizing some of the residual excess phosphorus (P*) in the surface waters to compensate for aerosol P deficiency. Regional primary productivity is further enhanced via the stimulation of nitrogen fixation fuelled by the residual atmospheric iron and P*. Our stoichiometric calculations reveal that a P* of 0.1 µmol L-1 can offset the P deficiency in atmospheric supply for many months. This study suggests that atmospheric deposition may sustain ~10% of primary production in both the western tropical Pacific.

  18. Impact of acid atmospheric deposition on soils: Field monitoring and aluminium chemistry.

    OpenAIRE

    Mulder, J.

    1988-01-01

    The effect of acid atmospheric deposition on concentrations and transfer of major solutes in acid, sandy soils was studied. Emphasis was given to mobilization and transport of potentially toxic aluminum. Data on solute concentrations and fluxes in meteoric water as well as soil solutions were obtained from intensive monitoring programmes conducted at a number of sites in northwestern Europe and North-America. Specific hypotheses were tested in laboratory experiments.Atmospheric acid inputs do...

  19. Atmospheric dry deposition in the vicinity of the Salton Sea, California - I: Air pollution and deposition in a desert environment

    Science.gov (United States)

    Alonso, R.; Bytnerowicz, A.; Boarman, W.I.

    2005-01-01

    Air pollutant concentrations and atmospheric dry deposition were monitored seasonally at the Salton Sea, southern California. Measurements of ozone (O 3), nitric acid vapor (HNO3), ammonia (NH3), nitric oxide (NO), nitrogen dioxide (NO2) and sulfur dioxide (SO 2) were performed using passive samplers. Deposition rates of NO 3-, NH4+, Cl-, SO 42-, Na+, K+ and Ca2+ to creosote bush branches and nylon filters as surrogate surfaces were determined for one-week long exposure periods. Maximum O3 values were recorded in spring with 24-h average values of 108.8 ??g m-3. Concentrations of NO and NO2 were low and within ranges of the non-urban areas in California (0.4-5.6 and 3.3-16.2 ??g m-3 ranges, respectively). Concentrations of HNO3 (2.0-6.7 ??g m-3) and NH 3 (6.4-15.7 ??g m-3) were elevated and above the levels typical for remote locations in California. Deposition rates of Cl-, SO42-, Na+, K+ and Ca2+ were related to the influence of sea spray or to suspended soil particles, and no strong enrichments caused by ions originated by human activities were detected. Dry deposition rates of NO3- and NH4+ were similar to values registered in areas where symptoms of nitrogen saturation and changes in species composition have been described. Deposition of nitrogenous compounds might be contributing to eutrophication processes at the Salton Sea. ?? 2005 Elsevier Ltd. All rights reserved.

  20. Atmospheric deposition of nitrogen to the Baltic Sea in the period 1995–2006

    OpenAIRE

    Bartnicki, J.; Semeena, V. S.; H. Fagerli

    2011-01-01

    The EMEP Unified model has been used to compute atmospheric nitrogen deposition into the Baltic Sea basin for the period of 12 years: 1995–2006. The level of annual total nitrogen deposition into the Baltic Sea basin has changed from 230 Gg N in 1995 to 199 Gg N in 2006, decreasing 13%. This value corresponds well with the total nitrogen emission reduction (11%) in the HELCOM Contracting Parties. However, inter-annual variability of nitrogen depositions to the Baltic Sea basin is relatively l...

  1. Atmospheric gaseous elemental mercury (GEM) concentrations and mercury depositions at a high-altitude mountain peak in south China

    OpenAIRE

    X. W. Fu; Feng, X.; Dong, Z. Q.; R. S. Yin; Wang, J. X.; Yang, Z. R.; Zhang, H.

    2010-01-01

    China is regarded as the largest contributor of mercury (Hg) to the global atmospheric Hg budget. However, concentration levels and depositions of atmospheric Hg in China are poorly known. Continuous measurements of atmospheric gaseous elemental mercury (GEM) were carried out from May 2008 to May 2009 at the summit of Mt. Leigong in south China. Simultaneously, deposition fluxes of THg and MeHg in precipitation, throughfall and litterfall were also studied. Atmospheric GEM concentrations aver...

  2. Assessment of toxicity in waters due to heavy metals derived from atmospheric deposition using Vibrio fischeri.

    Science.gov (United States)

    Cukurluoglu, Sibel; Muezzinoglu, Aysen

    2013-01-01

    Water toxicity originating from the atmospheric deposition of six heavy metals (Cd, Cr, Cu, Ni, Pb, Zn) was investigated on Vibrio fischeri activity in Izmir, Turkey. A LUMIStox® test was applied to dry and wet deposition samples and metal solutions. The inhibition levels and effective toxicity concentrations of these samples and solutions were determined. Interactive toxicity effects among the metals were investigated. When the impacts of the synthetic single heavy metal solutions were compared with each other, a toxicity ranking of Cr>Cd>Pb>Cu>Zn>Ni was obtained in order of decreasing severity. The total effective concentrations of these six metals were in the ranges of 0.074-0.221 mg/L and 0.071-0.225 mg/L for receiving aqueous solutions of dry and wet atmospheric depositions, respectively. The toxicity data showed that the wet deposition samples were 15% more toxic than the dry deposition samples. The interactive toxicity effects of the heavy metals in both dry and wet deposition samples were classified as antagonistic. High levels of heavy metals deposited in dissolved form may constitute an important input in the biochemical cycle and may have significant impacts. PMID:23030388

  3. Lichen-based critical loads for atmospheric nitrogen deposition in Western Oregon and Washington Forests, USA

    Energy Technology Data Exchange (ETDEWEB)

    Geiser, Linda H., E-mail: lgeiser@fs.fed.u [US Forest Service Pacific Northwest Region Air Resource Management Program, Siuslaw National Forest, PO Box 1148, Corvallis, OR 97339 (United States); Jovan, Sarah E. [US Forest Service Forest Inventory and Analysis Program, Pacific Northwest Research Station, 620 SW Main St, Suite 400, Portland, OR 97205 (United States); Glavich, Doug A. [US Forest Service Pacific Northwest Region Air Resource Management Program, Siuslaw National Forest, PO Box 1148, Corvallis, OR 97339 (United States); Porter, Matthew K. [Laboratory for Atmospheric Research, Washington State University, Pullman, WA 99164 (United States)

    2010-07-15

    Critical loads (CLs) define maximum atmospheric deposition levels apparently preventative of ecosystem harm. We present first nitrogen CLs for northwestern North America's maritime forests. Using multiple linear regression, we related epiphytic-macrolichen community composition to: 1) wet deposition from the National Atmospheric Deposition Program, 2) wet, dry, and total N deposition from the Communities Multi-Scale Air Quality model, and 3) ambient particulate N from Interagency Monitoring of Protected Visual Environments (IMPROVE). Sensitive species declines of 20-40% were associated with CLs of 1-4 and 3-9 kg N ha{sup -1} y{sup -1} in wet and total deposition. CLs increased with precipitation across the landscape, presumably from dilution or leaching of depositional N. Tight linear correlation between lichen and IMPROVE data suggests a simple screening tool for CL exceedance in US Class I areas. The total N model replicated several US and European lichen CLs and may therefore be helpful in estimating other temperate-forest lichen CLs. - Lichen-based critical loads for N deposition in western Oregon and Washington forests ranged from 3 to 9 kg ha{sup -1} y{sup -1}, increasing with mean annual precipitation.

  4. Conditional vulnerability of plant diversity to atmospheric nitrogen deposition across the United States

    Science.gov (United States)

    Simkin, Samuel M.; Allen, Edith B.; Bowman, William D.; Clark, Christopher M.; Belnap, Jayne; Brooks, Matthew L.; Cade, Brian S.; Collins, Scott L.; Geiser, Linda H.; Gilliam, Frank S.; Jovan, Sarah E.; Pardo, Linda H.; Schulz, Bethany K.; Stevens, Carly J.; Suding, Katharine N.; Throop, Heather L.; Waller, Donald M.

    2016-01-01

    Atmospheric nitrogen (N) deposition has been shown to decrease plant species richness along regional deposition gradients in Europe and in experimental manipulations. However, the general response of species richness to N deposition across different vegetation types, soil conditions, and climates remains largely unknown even though responses may be contingent on these environmental factors. We assessed the effect of N deposition on herbaceous richness for 15,136 forest, woodland, shrubland, and grassland sites across the continental United States, to address how edaphic and climatic conditions altered vulnerability to this stressor. In our dataset, with N deposition ranging from 1 to 19 kg N⋅ha−1⋅y−1, we found a unimodal relationship; richness increased at low deposition levels and decreased above 8.7 and 13.4 kg N⋅ha−1⋅y−1 in open and closed-canopy vegetation, respectively. N deposition exceeded critical loads for loss of plant species richness in 24% of 15,136 sites examined nationwide. There were negative relationships between species richness and N deposition in 36% of 44 community gradients. Vulnerability to N deposition was consistently higher in more acidic soils whereas the moderating roles of temperature and precipitation varied across scales. We demonstrate here that negative relationships between N deposition and species richness are common, albeit not universal, and that fine-scale processes can moderate vegetation responses to N deposition. Our results highlight the importance of contingent factors when estimating ecosystem vulnerability to N deposition and suggest that N deposition is affecting species richness in forested and nonforested systems across much of the continental United States.

  5. Historical atmospheric mercury emissions and depositions in North America compared to mercury accumulations in sedimentary records

    Science.gov (United States)

    Pirrone, Nicola; Allegrini, Ivo; Keeler, Gerald J.; Nriagu, Jerome O.; Rossmann, Ronald; Robbins, John A.

    Gold and silver production in North America (included United States, Canada and Mexico) released a large amount of mercury to the atmosphere until well into this century when mercury (Hg) amalgamation was replaced by cyanide concentration. Since then, emissions from industries have been the dominant anthropogenic sources of atmospheric Hg in North America as a whole. Past Hg emissions from gold and silver extractions in North America during the 1800s do not show a clear evidence of atmospheric deposition occurred at the coring sites considered in this study. Estimated atmospheric emissions of Hg in North America peaked in 1879 (at about 1708 t yr -1) and 1920 (at about 940 t yr -1), primarily due to Hg emissions from gold and silver mining. After the Great Economic Depression (1929) Hg emissions peaked again in the 1947 (274 t yr -1), in 1970 (325 t yr -1) and in 1989 (330 t yr -1) as result of increased Hg emissions from industrial sources, though improvements in the emissions control technology in United States and Canada have been substantial. Estimates of total atmospheric deposition fluxes of Hg to water and terrestrial receptors were in the range of 14.3-19.8 μg m -2 yr -1 in North America as a whole, and averaged 135 μg m -2 yr -1 (global background + local emissions) in the Great Lakes. These values were in good agreement with recent estimates reported in literature. The comparison of atmospheric Hg deposition fluxes with Hg accumulation rates in sediment cores suggests that atmospheric deposition was the major source of Hg entering the lakes system at coring sites, however, important contributions to Lake Ontario sediment cores sites from 1940 to 1970 were likely originated from local point sources (i.e. direct discharges).

  6. Spatial pattern and temporal changes in the NH4+/NO3- ratio in atmospheric deposition in Czech forests

    Science.gov (United States)

    Hunova, Iva; Kurfurst, Pavel; Stráník, Vojtěch

    2016-04-01

    The ratio between NH4+ and NO3- in wet atmospheric deposition is an essential indicator of atmospheric chemistry, reflects the share of emission sources (Du et al., 2014), and is also important regarding the nitrogen deposition environmental impacts. There are evidences for differential effects of reduced and oxidised nitrogen deposition on vegetation independent of nitrogen load (van den Berg et al., 2016). NH4+ deposition appears to be more effective than NO3- deposition in decreasing biodiversity and is more harmful to vegetation (Erisman et al., 2007). We present temporal trends and spatial patterns for NH4+/NO3- ratio on one-country scale based on long-term monitoring precipitation chemistry in Central European forests. We discuss the indicated changes within the changing emission patterns. Acknowledgements: We would like to acknowledge the grant GA14-12262S - Effects of changing growth conditions on tree increment, stand production and vitality - danger or opportunity for the Central-European forestry? for support of this contribution. The input data used for the analysis were provided by the Czech Hydrometeorological Institute. References: Du, E., de Vries, W., Galloway, J.N., Hu, X., Fang, J., 2014. Changes in wet nitrogen deposition in the United States between 1985 and 2012. Environmental Research Letters 9, 095004. Erisman, J.W., Bleeker, A., Galloway, J.N., Sutton, M.S., 2007. Reduced nitrogen in ecology and the environment. Environmental Pollution 150, 140-149. van den Berg, L.J.L., Jones L., Sheppard, L.J., Smart, S.M., Bobbink, R., Dise, N.B., Ashmore, M.R., 2016. Evidence for differential effects of reduced and oxidized nitrogen deposition on vegetation independent of nitrogen load. Environmental Pollution 208, 890-897.

  7. Equipment for atmospheric, spatial atomic layer deposition in roll-to-roll processes

    NARCIS (Netherlands)

    Knaapen, R.; Poodt, P.; Olieslagers, R.; Lankhorst, A.; Boer, M. van den; Berg, D. van den; Asten, A. van; Roozeboom, F.

    2012-01-01

    A novel type of reactor has been designed for atmospheric atomic layer deposition (ALD) on flexible substrates. In the reactor, a flexible substrate slowly advances around a fast rotating drum. Gas bearing technology is used to prevent physical contact between the flexible substrate and the drum, an

  8. INTERMEDIATE-RANGE GRID MODEL FOR ATMOSPHERIC SULFUR DIOXIDE AND SULFATE CONCENTRATIONS AND DEPOSITIONS

    Science.gov (United States)

    A three-dimensional time-dependent grid type model for two chemically reacting species which undergo atmospheric transport, diffusion and wet and dry deposition over a region of several hundred km is presented. Accuracy and sensitivity of the model are discussed. The model is app...

  9. ATMOSPHERIC DEPOSITION OF TOXIC METALS TO LAKE MICHIGAN: PRELIMINARY ANNUAL MODEL CALCULATIONS

    Science.gov (United States)

    Concern is growing for the environmental water quality of the Great Lakes. tmospheric deposition of toxic substances is recognized as a major pathway of contaminants to the water medium. o estimate the annual atmospheric loadings of five toxic metals -- arsenic (As), cadmium (Cd)...

  10. Atmospheric spatial atomic layer deposition of in-doped ZnO

    NARCIS (Netherlands)

    Illiberi, A.; Scherpenborg, R.; Roozeboom, F.; Poodt, P.

    2014-01-01

    Indium-doped zinc oxide (ZnO:In) has been grown by spatial atomic layer deposition at atmospheric pressure (spatial-ALD). Trimethyl indium (TMIn), diethyl zinc (DEZ) and deionized water have been used as In, Zn and O precursor, respectively. The metal content of the films is controlled in the range

  11. Spatial atmospheric atomic layer deposition of InxGayZnzO for thin film transistors

    NARCIS (Netherlands)

    Illiberi, A.; Cobb, B.; Sharma, A.; Grehl, T.; Brongersma, H.; Roozeboom, F.; Gelinck, G.; Poodt, P.

    2015-01-01

    We have investigated the nucleation and growth of InGaZnO thin films by spatial atmospheric atomic layer deposition. Diethyl zinc (DEZ), trimethyl indium (TMIn), triethyl gallium (TEGa), and water were used as Zn, In, Ga and oxygen precursors, respectively. The vaporized metal precursors have been c

  12. Biomagnetic monitoring of heavy metals contamination in deposited atmospheric dust, a case study from Isfahan, Iran.

    Science.gov (United States)

    Norouzi, Samira; Khademi, Hossein; Cano, Angel Faz; Acosta, Jose A

    2016-05-15

    Tree leaves are considered as one of the best biogenic dust collectors due to their ability to trap and retain particulate matter on their surfaces. In this study, the magnetic susceptibility (MS) and the concentration of selected heavy metals of plane tree (Platanus orientalis L.) leaves and deposited atmospheric dust, sampled by an indirect and a direct method, respectively, were determined to investigate the relationships between leaf magnetic parameters and the concentration of heavy metals in deposited atmospheric dust. The objective was to develop a biomagnetic method as an alternative to the common ones used for determining atmospheric heavy metal contaminations. Plane tree leaves were monthly sampled on the 19th of May to November, 2012 (T1-T7), for seven months from 21 different sites in the city of Isfahan, central Iran. Deposited atmospheric dust samples were also collected using flat glass surfaces from the same sites on the same dates, except for T1. MS (χlf, χhf) values in washed (WL) and unwashed leaves (UL) as well as Cu, Fe, Mn, Ni, Pb, and Zn concentrations in UL and deposited atmospheric dust samples were determined. The results showed that the MS content with a biogenic source was low with almost no significant change during the sampling period, while an increasing trend was observed in the MS content of UL samples due to the deposition of heavy metals and magnetic particles on leaf surfaces throughout the plant growth. The latter type of MS content could be reduced through washing off by rain. Most heavy metals examined, as well as the Tomlinson pollution load index (PLI) in UL, showed statistically significant correlations with MS values. The correlation between heavy metals content in atmospheric dust deposited on glass surfaces and leaf MS values was significant for Cu, Fe, Pb, and Zn. Moreover, the similarity observed between the spatial distribution maps of leaf MS and deposited atmospheric dust PLI provided convincing evidence regarding

  13. Comparison of Mercury Mass Loading in Streams to Wet and Dry Atmospheric Deposition in Watersheds of the Western US: Evidence for Non-Atmospheric Mercury Sources

    Science.gov (United States)

    Domagalski, J. L.; Majewski, M. S.; Alpers, C. N.; Eckley, C.

    2015-12-01

    Many streams in the western United States (US) are listed as impaired by mercury (Hg), and it is important to understand the magnitudes of the various sources in order to implement management strategies. Atmospheric deposition of Hg and can be a major source of aquatic contamination, along with mine wastes, and other sources. Prior studies in the eastern US have shown that streams deliver less than 50% of the atmospherically deposited Hg on an annual basis. In this study, we compared annual stream Hg loads for 20 watersheds in the western US to measured wet and modeled dry deposition. Land use varies from undisturbed to mixed (agricultural, urban, forested, mining). Data from the Mercury Deposition Network was used to estimate Hg input from precipitation. Dry deposition was not directly measured, but can be modeled using the Community Multi-scale Air Quality model. At an undeveloped watershed in the Rocky Mountains, the ratio of stream Hg load to atmospheric deposition was 0.2 during a year of average precipitation. In contrast, at the Carson River in Nevada, with known Hg contamination from historical silver mining with Hg amalgamation, stream export exceeded atmospheric deposition by a factor of 60, and at a small Sierran watershed with gold mining, the ratio was 70. Larger watersheds with mixed land uses, tend to have lower ratios of stream export relative to atmospheric deposition suggesting storage of Hg. The Sacramento River was the largest watershed for which Hg riverine loads were available with an average ratio of stream Hg export to atmospheric deposition of 0.10. Although Hg was used in upstream historical mining operations, the downstream river Hg load is partially mitigated by reservoirs, which trap sediment. This study represents the first compilation of riverine Hg loads in comparison to atmospheric deposition on a regional scale; the approach may be useful in assessing the relative importance of atmospheric and non-atmospheric Hg sources.

  14. Structural and Luminescent Properties of ZnO Thin Films Deposited by Atmospheric Pressure Chemical Vapour Deposition

    Institute of Scientific and Technical Information of China (English)

    ZHAO Guo-Liang; LIN Bi-Xia; HONG Liang; MENG Xiang-Dong; FU Zhu-Xi

    2004-01-01

    ZnO thin films were successfully deposited on Si (100) substrates by chemical vapour deposition (CVD) at atmospheric pressure (1 atm). The only solid source used here is zinc acetate, (CHsCOO)2Zn, and the carrier gas is nitrogen. The sample, which was prepared at 550℃ during growth and then annealed in air at 900℃ , has only a ZnO (002) diffraction peak at 34.6° with its FWHM of 0.23° in the XRD pattern. The room-temperature PL spectrum shows a strong ultraviolet emission with the peak centred at 380nm. We analysed the effects of many factors, such as the source, substrates, growth and annealing temperatures, and annealing ambience, on the structural and optical properties of our prepared ZnO films.

  15. Atmospheric deposition patterns of (210)Pb and (7)Be in Cienfuegos, Cuba.

    Science.gov (United States)

    Alonso-Hernández, Carlos M; Morera-Gómez, Yasser; Cartas-Águila, Héctor; Guillén-Arruebarrena, Aniel

    2014-12-01

    The radiometric composition of bulk deposition samples, collected monthly for one year, February 2010 until January 2011, at a site located in Cienfuegos (22° 03' N, 80° 29' W) (Cuba), are analysed in this paper. Measurement of (7)Be and (210)Pb activity concentrations were carried out in 12 bulk deposition samples. The atmospheric deposition fluxes of (7)Be and (210)Pb are in the range of 13.2-132 and 1.24-8.29 Bq m(-2), and their mean values are: 56.6 and 3.97 Bq m(-2), respectively. The time variations of the different radionuclide have been discussed in relation with meteorological factors and the mean values have been compared to those published in recent literature from other sites located at different latitudes. The annual average flux of (210)Pb and (7)Be were 47 and 700 Bq m(-2) y(-1), respectively. Observed seasonal variations of deposition data are explained in terms of different environmental features. The atmospheric deposition fluxes of (7)Be and (210)Pb were moderately well correlated with precipitation and well correlated with one another. The (210)Pb/(7)Be ratios in the monthly depositions samples varied in the range of 0.05-0.10 and showed a strong correlation with the number of rainy days.

  16. Atmospheric deposition patterns of (210)Pb and (7)Be in Cienfuegos, Cuba.

    Science.gov (United States)

    Alonso-Hernández, Carlos M; Morera-Gómez, Yasser; Cartas-Águila, Héctor; Guillén-Arruebarrena, Aniel

    2014-12-01

    The radiometric composition of bulk deposition samples, collected monthly for one year, February 2010 until January 2011, at a site located in Cienfuegos (22° 03' N, 80° 29' W) (Cuba), are analysed in this paper. Measurement of (7)Be and (210)Pb activity concentrations were carried out in 12 bulk deposition samples. The atmospheric deposition fluxes of (7)Be and (210)Pb are in the range of 13.2-132 and 1.24-8.29 Bq m(-2), and their mean values are: 56.6 and 3.97 Bq m(-2), respectively. The time variations of the different radionuclide have been discussed in relation with meteorological factors and the mean values have been compared to those published in recent literature from other sites located at different latitudes. The annual average flux of (210)Pb and (7)Be were 47 and 700 Bq m(-2) y(-1), respectively. Observed seasonal variations of deposition data are explained in terms of different environmental features. The atmospheric deposition fluxes of (7)Be and (210)Pb were moderately well correlated with precipitation and well correlated with one another. The (210)Pb/(7)Be ratios in the monthly depositions samples varied in the range of 0.05-0.10 and showed a strong correlation with the number of rainy days. PMID:25233214

  17. Atmospheric deposition of nitrogen to the Baltic Sea in the period 1995–2006

    Directory of Open Access Journals (Sweden)

    J. Bartnicki

    2011-01-01

    Full Text Available The EMEP Unified model has been used to compute atmospheric nitrogen deposition into the Baltic Sea basin for the period of 12 years: 1995–2006. The level of annual total nitrogen deposition into the Baltic Sea basin has changed from 230 Gg N in 1995 to 199 Gg N in 2006, decreasing 13%. This value corresponds well with the total nitrogen emission reduction (11% in the HELCOM Contracting Parties. However, inter-annual variability of nitrogen depositions to the Baltic Sea basin is relatively large, ranging from −13% to +17% of the averaged value. It is mainly caused by the changing meteorological conditions and especially precipitation in the considered period. The calculated monthly depositions are similar for most of the years showing maxima in the autumn months October and November. The source allocation budget for atmospheric nitrogen deposition to the Baltic Sea basin was calculated for each year of the period 1997–2006. The main emission sources contributing to total nitrogen deposition are: Germany 18–22 %, Poland 11–13% and Denmark 8–11%. There is also a significant contribution from distant sources like the United Kingdom 6–10%, as well as from the international ship traffic on the Baltic Sea 4–5%.

  18. Atmospheric deposition of nitrogen to the Baltic Sea in the period 1995–2006

    Directory of Open Access Journals (Sweden)

    J. Bartnicki

    2011-10-01

    Full Text Available The EMEP/MSC-W model has been used to compute atmospheric nitrogen deposition into the Baltic Sea basin for the period of 12 yr: 1995–2006. The level of annual total nitrogen deposition into the Baltic Sea basin has changed from 230 Gg N in 1995 to 199 Gg N in 2006, decreasing 13 %. This value corresponds well with the total nitrogen emission reduction (11 % in the HELCOM Contracting Parties. However, inter-annual variability of nitrogen deposition to the Baltic Sea basin is relatively large, ranging from −13 % to +17 % of the averaged value. It is mainly caused by the changing meteorological conditions and especially precipitation in the considered period. The calculated monthly deposition pattern is similar for most of the years showing maxima in the autumn months October and November. The source allocation budget for atmospheric nitrogen deposition to the Baltic Sea basin was calculated for each year of the period 1997–2006. The main emission sources contributing to total nitrogen deposition are: Germany 18–22 %, Poland 11–13 % and Denmark 8–11 %. There is also a significant contribution from distant sources like the United Kingdom 6–9 %, as well as from the international ship traffic on the Baltic Sea 4–5 %.

  19. Development and Implementation of Critical Loads for Atmospheric Deposition: Federal Land Management Implications

    Science.gov (United States)

    Porter, E. M.

    2004-12-01

    Critical loads for atmospheric deposition have been widely developed and used in Europe, Canada, and other countries. Critical loads are used to influence air pollution emissions reductions, thereby protecting and restoring aquatic and terrestrial ecosystems. In the United States, federal land management agencies are adopting the critical load concept as a potentially valuable resource management tool. Certain parks and wilderness areas are currently being affected by anthropogenic nitrogen and sulfur deposition. Effects of excess deposition include acidification, nitrogen enrichment, toxicity, and changes in biotic communities. Streams in both Shenandoah and Great Smoky Mountains National Parks are experiencing chronic and episodic acidification and brook trout fisheries in Shenandoah have been affected. High elevation ecosystems in Rocky Mountain National Park are undergoing subtle changes in aquatic and terrestrial ecosystems attributable to atmospheric deposition. Natural resources in many other federal areas have been affected or are at risk from deposition. Federal land managers are refining strategies for critical loads that include working with scientists to identify resources sensitive to deposition, defining resource protection criteria that will meet management objectives, and estimating and implementing critical loads. Critical loads will be used in resource management decisions and federal land management planning. They will be used to evaluate management actions and assess progress towards meeting management goals. Federal land managers will also communicate critical loads information to air pollution regulatory agencies to inform emissions management strategies for clean air.

  20. Deuterium retention in the carbon co-deposition layers deposited by magnetron sputtering in D2/He atmosphere

    International Nuclear Information System (INIS)

    Carbon was deposited on Si and W substrates using a D2/He plasma in a radio frequency magnetron sputtering system. The deposited layers were examined with ion beam analysis (IBA), Raman spectra analysis (RS) and scanning electron microscopy (SEM). The growth rate of the layers deposited at 2.5 Pa total pressure and 300 K decreased with increasing He fraction in the D2/He gas mixture. The deuterium concentration in the layers deposited on the Si substrate increased from 14% to 28% when the flow rate of the He gas relative to the D2 gas was varied from 0.125 to 0.5, but the deuterium concentration in the layers on a W substrate decreased from 24% to 14%. Deuterium or helium retention and the layer thickness all significantly decreased when the substrate temperature was increased from 423 K to 773 K. Raman analysis showed that the deposited layers were amorphous deuterated-carbon layers (named a-C: D layer) and the extent of bond disorder increased dramatically with the increasing helium content in the film. Blisters and bubbles occurred in the films for high helium content in the films, and surface cracking and exfoliation were also observed

  1. Atmospheric deposition of nutrients, pesticides, and mercury in Rocky Mountain National Park, Colorado, 2002

    Science.gov (United States)

    Mast, M. Alisa; Campbell, Donald H.; Ingersoll, George P.; Foreman, William T.; Krabbenhoft, David P.

    2003-01-01

    Nutrients, current-use pesticides, and mercury were measured in atmospheric deposition during summer in Rocky Mountain National Park in Colorado to improve understanding of the type and magnitude of atmospheric contaminants being deposited in the park. Two deposition sites were established on the east side of the park: one at an elevation of 2,902 meters near Bear Lake for nutrients and pesticides, and one at an elevation of 3,159 meters in the Loch Vale watershed for mercury. Concentrations of nutrients in summer precipitation at Bear Lake ranged from less than 0.007 to 1.29 mg N/L (milligrams of nitrogen per liter) for ammonium and 0.17 to 4.59 mg N/L for nitrate and were similar to those measured at the Loch Vale National Atmospheric Deposition Network station, where nitrogen concentrations in precipitation are among the highest in the Rocky Mountains. Atrazine, dacthal, and carbaryl were the most frequently detected pesticides at Bear Lake, with carbaryl present at the highest concentrations (0.0079 to 0.0952 ?g/L (micrograms per liter), followed by atrazine (less than 0.0070 to 0.0604 ?g/L), and dacthal (0.0030 to 0.0093 ?g/L). Mercury was detected in weekly bulk deposition samples from Loch Vale in concentrations ranging from 2.6 to 36.2 ng/L (nanograms per liter). Concentrations in summer precipitation were combined with snowpack data from a separate study to estimate annual deposition rates of these contaminants in 2002. Annual bulk nitrogen deposition in 2002 was 2.28 kg N/ha (kilograms of nitrogen per hectare) at Bear Lake and 3.35 kg N/ha at Loch Vale. Comparison of wet and bulk deposition indicated that dry deposition may account for as much as 28 percent of annual nitrogen deposition, most of which was deposited during the summer months. Annual deposition rates for three pesticides were estimated as 45.8 mg/ha (milligrams per hectare) of atrazine, 14.2 mg/ha of dacthal, and 54.8 mg/ha of carbaryl. Because of much higher pesticide concentrations in

  2. Fractionation of trace elements in total atmospheric deposition by filtrating-bulk passive sampling.

    Science.gov (United States)

    Rueda-Holgado, F; Palomo-Marín, M R; Calvo-Blázquez, L; Cereceda-Balic, F; Pinilla-Gil, E

    2014-07-01

    We have developed and validated a new simple and effective methodology for fractionation of soluble and insoluble forms of trace elements in total atmospheric deposition. The proposed methodology is based on the modification of a standard total deposition passive sampler by integrating a quartz fiber filter that retains the insoluble material, allowing the soluble fraction to pass through and flow to a receiving bottle. The quartz filter containing the insoluble fraction and the liquid containing the soluble fraction are then separately assayed by standardized ICP-MS protocols. The proposed atmospheric elemental fractionation sampler (AEFS) was validated by analyzing a Coal Fly Ash reference material with proper recoveries, and tested for field fractionation of a set of 10 key trace elements in total atmospheric deposition at the industrial area of Puchuncaví-Ventanas, Chile. The AEFS was proven useful for pollution assessment and also to identify variability of the soluble and insoluble fractions of the selected elements within the study area, improving the analytical information attainable by standard passive samplers for total deposition without the need of using sophisticated and high cost wet-only/dry only collectors.

  3. The impact of atmospheric deposition of cadmium on dominant algal species in the East China Sea

    Science.gov (United States)

    Quan, Qiwei; Chen, Ying; Ma, Qingwei; Wang, Fujiang; Meng, Xi; Wang, Bo

    2016-04-01

    Cadmium (Cd) mainly derived from anthropogenic emissions can be transported through atmospheric pathway to marine ecosystem, affecting the phytoplankton community and primary productivity. In this study, we identified the toxicity threshold of Cd for phytoplankton under seawater conditions of the coastal East China Sea (ECS) through both laboratory and in situ mesocosm incubation experiments. The mesocosm experiment showed that Cd in low concentration (0.003 μg per μg chl a) was conducive to the growth of natural community and increased chl a productivity. In high concentration (0.03 μg per μg chl a) Cd acted as an inhibiting factor which decreased the total chl a productivity. The diatom community was found to be more sensitive to Cd toxicity than dinoflagellate, as the low concentration Cd showed toxicity to diatom but enhanced dinoflagellate growth. We noticed that the soluble Cd estimated from atmosphere deposition to the coastal ECS was below the toxicity threshold and the Cd deposition might promote phytoplankton growth in this region. In our laboratory experiments, adding Cd, similar to aerosol deposition, stimulated the growth of both dominant algal species Prorocentrum donghaiense Lu (dinoflagellate) and Skeletonema costatum (diatom). Adding Cd on a higher level inhibited the growth of both the species, but Skeletonema costatum seemed obviously more sensitive to toxicity. This indicates the potential impact of atmospheric deposition Cd on phytoplankton community succession in the ECS.

  4. Reconciling modeled and observed atmospheric deposition of soluble organic nitrogen at coastal locations

    Science.gov (United States)

    Ito, Akinori; Lin, Guangxing; Penner, Joyce E.

    2014-06-01

    Atmospheric deposition of reactive nitrogen (N) species from air pollutants is a significant source of exogenous nitrogen in marine ecosystems. Here we use an atmospheric chemical transport model to investigate the supply of soluble organic nitrogen (ON) from anthropogenic sources to the ocean. Comparisons of modeled deposition with observations at coastal and marine locations show good overall agreement for inorganic nitrogen and total soluble nitrogen. However, previous modeling approaches result in significant underestimates of the soluble ON deposition if the model only includes the primary soluble ON and the secondary oxidized ON in gases and aerosols. Our model results suggest that including the secondary reduced ON in aerosols as a source of soluble ON contributes to an improved prediction of the deposition rates (g N m-2 yr-1). The model results show a clear distinction in the vertical distribution of soluble ON in aerosols between different processes from the primary sources and the secondary formation. The model results (excluding the biomass burning and natural emission changes) suggest an increase in soluble ON outflow from atmospheric pollution, in particular from East Asia, to the oceans in the twentieth century. These results highlight the necessity of improving the process-based quantitative understanding of the chemical reactions of inorganic nitrogen species with organics in aerosol and cloud water.

  5. Characterization of atmospheric deposition and runoff water in a small suburban catchment.

    Science.gov (United States)

    Lamprea, Katerine; Ruban, Véronique

    2011-07-01

    A study has been carried out as part of the mission assigned to IRSTV (Research Institute of Urban Sciences and Techniques), a federative research network supported by the Loire Valley Region, with the objective of characterizing atmospheric deposition, roof runoff and street runoff in a small (31 ha) suburban catchment in Nantes equipped with a separate sewer system. Trace metals, polycyclic aromatic hydrocarbons (PAHs) and pesticides were investigated. The characterization of atmospheric deposition reveals a high variability of trace metal concentrations, which could not be explained by rainfall characteristics. The relative abundance order of the metals was as follows: Zn > Cu > Cr approximately Ni > Cd. Organic pollutants, i.e., PAHs and pesticides, were only rarely detected in the atmospheric deposition. Zn and Pb appear to be the major contaminants in runoff water, whereas the concentrations of Ni, Cu, Cr, Cd, PAHs and pesticides tend to remain low. On the whole, concentrations were similar to the lowest range reported in the literature. According to statutory thresholds, runoff water quality is poor because of the high Pb and Zn concentrations. Based on scanning electron microscopy observations, atmospheric particles do not apparently differ from runoff particles, with a predominance of pollen, bacteria and particles resulting from soil erosion. Spherical organic particles produced during fuel combustion have also been observed. PMID:21882566

  6. [Pollution evaluation and health risk assessment of heavy metals from atmospheric deposition in Lanzhou].

    Science.gov (United States)

    Li, Ping; Xue, Su-Yin; Wang, Sheng-Li; Nan, Zhong-Ren

    2014-03-01

    In order to evaluate the contamination and health risk of heavy metals from atmospheric deposition in Lanzhou, samples of atmospheric deposition were collected from 11 sampling sites respectively and their concentrations of heavy metals were determined. The results showed that the average contents of Cu, Pb, Cd, Cr, Ni, Zn and Mn were 82.22, 130.31, 4.34, 88.73, 40.64, 369.23 and 501.49 mg x kg(-1), respectively. There was great difference among different functional areas for all elements except Mn. According to the results, the enrichment factor score of Mn was close to 1, while the enrichment of Zn, Ni, Cu and Cr was more serious, and Pb and Cd were extremely enriched. The assessment results of geoaccumulation index of potential ecological risk indicated that the pollution of Cd in the atmospheric deposition of Lanzhou should be classified as extreme degree, and that of Cu, Ni, Zn, Pb as between slight and extreme degrees, and Cr as practically uncontaminated. Contaminations of atmospheric dust by heavy metals in October to the next March were more serious than those from April to August. Health risk assessment indicated that the heavy metals in atmospheric deposition were mainly ingested by human bodies through hand-mouth ingestion. The non-cancer risk was higher for children than for adults. The order of non-cancer hazard indexes of heavy metals was Pb > Cr > Cd > Cu > Ni > Zn. The non-cancer hazard indexes and carcinogen risks of heavy metals were both lower than their threshold values, suggesting that they will not harm the health.

  7. Atmospheric deposition and watershed nitrogen export along an elevational gradient in the Catskill Mountains, New York

    Science.gov (United States)

    Lawrence, G.B.; Lovett, Gary M.; Baevsky, Y.H.

    2000-01-01

    Cumulative effects of atmospheric N deposition may increase N export from watersheds and contribute to the acidification of surface waters, but natural factors (such as forest productivity and soil drainage) that affect forest N cycling can also control watershed N export. To identify factors that are related to stream-water export of N, elevational gradients in atmospheric deposition and natural processes were evaluated in a steep, first-order watershed in the Catskill Mountains of New York, from 1991 to 1994. Atmospheric deposition of SO4/2-, and probably N, increased with increasing elevation within this watershed. Stream-water concentrations of SO4/2- increased with increasing elevation throughout the year, whereas stream-water concentrations of NO3/- decreased with increasing elevation during the winter and spring snowmelt period, and showed no relation with elevation during the growing season or the fall. Annual export of N in stream water for the overall watershed equaled 12% to 17% of the total atmospheric input on the basis of two methods of estimation. This percentage decreased with increasing elevation, from about 25% in the lowest subwatershed to 7% in the highest subwatershed; a probable result of an upslope increase in the thickness of the surface organic horizon, attributable to an elevational gradient in temperature that slows decomposition rates at upper elevations. Balsam fir stands, more prevalent at upper elevations than lower elevations, may also affect the gradient of subwatershed N export by altering nitrification rates in the soil. Variations in climate and vegetation must be considered to determine how future trends in atmospheric deposition will effect watershed export of nitrogen.

  8. Polybrominated diphenyl ethers at a solid waste incineration plant II: atmospheric deposition

    Science.gov (United States)

    ter Schure, Arnout F. H.; Agrell, Cecilia; Bokenstrand, Alma; Sveder, Jeanette; Larsson, Per; Zegers, Bart N.

    2004-09-01

    In the second of two papers, the atmospheric polybrominated diphenyl ethers (PBDE) deposition (wet and dry) at a municipal solid waste incineration (MSW) plant with electronics recycling is compared with that at an industrial urban reference site (URS) producing asphalt and concrete. Results of BDE209 and ΣPBDE excluding BDE209 as representatives of "new" vs. "old" PBDEs are presented. Volume weighted mean ΣPBDE and BDE209 concentrations at the MSW were 6.2 and 14.4 ng l-1, and at the URS were 2.5 and 14.1 ng l-1. Median ΣPBDE and BDE209 deposition fluxes were 21.3, 63.8 and 7.0, 14.7 ng m-2 day-1 at the MSW and URS, respectively. The concentrations in precipitation and the deposition fluxes were significantly higher at the MSW compared to the URS. Measured total washout- ratios (WT) were dependent on particle scavenging and the median WT for all congeners was 5.4×105. Median dry particle deposition velocities ranged from 0.4 to 49 cm s-1, depending on congener, showing that PBDEs are effectively removed from the atmosphere by particle deposition. PBDE fluxes increased at the reference site when winds were blowing from west-south-west, i.e. from the direction of the MSW. PBDE deposition and washout ratios were not influenced by temperature or rain volume, suggesting a constant emission from the MSW regardless of weather conditions. Together with the results of paper I (Agrell et al., 2004, Atmospheric Environment, this issue) we therefore suggest that treatment of waste, e.g. electronics recycling, is more a source of "old" PBDEs to the environment, whereas the rather similar BDE209 concentrations at the two urban sites are more a result of proximity to potential diffuse sources.

  9. Atmospheric Ionic Deposition in Tropical Sites of Central Sulawesi Determined by Ion Exchange Resin Collectors and Bulk Water Collector

    OpenAIRE

    Köhler, S; Jungkunst, H.; Gutzler, C.; Herrera, R.; Gerold, G

    2012-01-01

    In the light of global change, the necessity to monitor atmospheric depositions that have relevant effects on ecosystems is ever increasing particularly for tropical sites. For this study, atmospheric ionic depositions were measured on tropical Central Sulawesi at remote sites with both a conventional bulk water collector system (BWS collector) and with a passive ion exchange resin collector system (IER collector). The principle of IER collector to fix all ionic depositions, i.e. anions and c...

  10. [Atmospheric deposition fluxes and seasonal variations of elements in northeast of Sichuan, central China].

    Science.gov (United States)

    Tong, Xiao-Ning; Zhou, Hou-Yun; You, Chen-Feng; Tang, Jing; Liu, Hou-Chun; Huang, Ying; He, Hai-Bo

    2014-01-01

    Monthly atmospheric deposition was collected in Northeast of Sichuan Province from August 2011 to July 2012. Contents of Na, Mg, Ca, K, Si, Sr, Ba and Zn in weak-acid leachable fraction (with pH values of ca. 2) of the deposition were determined using ICP-MS. The results indicated that the deposition fluxes of all these elements exhibited notable seasonal variations. For example, the deposition flux of Na increased with precipitation, suggesting a dominant derivation from wet deposition; whereas the fluxes of Ca, Ba, Si, Sr and Mg displayed higher values during winter or spring season, suggesting that these elements may be closely associated with atmospheric dust activity. The annual fluxes of these elements were remarkably different in value. Na had the highest flux of 30 497 microg x (10(2) cm2 x a)(-1), more than three orders of magnitude higher than the lowest flux of Ba of 27.4 microg x (10(2) cm2 x a)(-1).

  11. ENVIRONMENTAL MONITORING USING LINDEN TREE LEAVES AS NATURAL TRAPS OF ATMOSPHERIC DEPOSITION: A PILOT STUDY IN TRANSILVANIA, ROMANIA

    OpenAIRE

    MIHÁLY BRAUN; ZITA MARGITAI; ALBERT TÓTH; MARTINE LEERMAKERS

    2007-01-01

    Atmospheric pollution caused by toxic elements is an emerging problem of concern. Tree leaves have been widely used as indicator of atmospheric pollutions and they are effective alternatives to the moreusual biomonitoring methods. Tree leaves can be used as natural traps of atmospheric deposition. Elemental composition of dust deposited onto leaf surfaces can be used to characterize the urban environment. A pilot survey including 16 Romanian settlements was carried out in order to evaluate th...

  12. Atmospheric Deposition And MediterraneAN sea water productiviTy (Thales - ADAMANT) An overview

    Science.gov (United States)

    Christodoulaki, Sylvia; Petihakis, George; Triantafyllou, George; Pitta, Paraskevi; Papadimitriou, Vassileios; Tsiaras, Konstantinos; Mihalopoulos, Nikolaos; Kanakidou, Maria

    2015-04-01

    In the marine environment the salinity and biological pumps sequester atmospheric carbon dioxide. The biological pump is directly related to marine primary production which is controlled by nutrient availability mainly of iron, nitrogen and phosphorus. The Mediterranean Sea, especially the eastern basin is one of the most oligotrophic seas. The nitrogen (N) to phosphorus (P) ratio is unusually high, especially in the eastern basin (28:1) and primary production is limited by phosphorus availability. ADAMANT project contributes to new knowledge into how nutrients enter the marine environment through atmospheric deposition, how they are assimilated by organisms and how this influences carbon and nutrient fluxes. Experimental work has been combined with atmospheric and marine models. Important knowledge is obtained on nutrients deposition through mesocosm experiments on their uptake by the marine systems and their effects on the marine carbon cycle and food chain. Kinetic parameters of adsorption of acidic and organic volatile compounds in atmospheric samples of dust and marine salts are estimated in conjunction with solubility of N and P in mixtures contained in dust. Atmospheric and oceanographic models are coupled to create a system that is able to holistically simulate the effects of atmospheric deposition on the marine environment over time, beginning from the pre-industrial era until the future years (hind cast, present and forecast simulations). This research has been co-financed by the European Union (European Social Fund) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework - Research Funding Program: THALES, Investing in knowledge society through European Social Fund.

  13. Impact of biomass burning on surface water quality in Southeast Asia through atmospheric deposition: field observations

    Science.gov (United States)

    Sundarambal, P.; Balasubramanian, R.; Tkalich, P.; He, J.

    2010-03-01

    Atmospheric nutrients have recently gained attention as a significant additional source of new nitrogen (N) and phosphorus (P) loading to the ocean. The effect of atmospheric N on marine productivity depends on the biological availability of both inorganic and organic N and P forms. During October 2006, the regional smoke haze episode in Southeast Asia (SEA) that resulted from uncontrolled forest fires in Sumatra and Borneo blanketed large tracts of the region. In this work, we determined the composition of nutrients in aerosols and rainwater during haze and non-haze periods to assess their impacts on aquatic ecosystem in SEA for the first time. We compared atmospheric dry and wet deposition of N and P species in aerosol and rainwater in Singapore between haze and non haze periods. Air mass back trajectories showed that large-scale forest and peat fires in Sumatra and Kalimantan were a significant source of atmospheric nutrients to aquatic environments in Singapore and SEA region on hazy days. It was observed that the average concentrations of nutrients increased approximately by a factor of 3 to 8 on hazy days when compared with non-hazy days. The mean dry atmospheric fluxes (g/m2/year) of TN and TP observed during hazy and non-hazy days were 4.77±0.775 and 0.3±0.082, and 0.91±0.471 and 0.046±0.01, respectively. The mean wet deposition fluxes (g/m2/year) of TN and TP were 12.2±3.53 and 0.726±0.074, and 2.71±0.989 and 0.144±0.06 for hazy and non-hazy days, respectively. The occurrences of higher concentrations of nutrients from atmospheric deposition during smoke haze episodes may have adverse consequences on receiving aquatic ecosystems with cascading impacts on water quality.

  14. Atmospheric mecury deposition in alpine snow, northern British Columbia and southwestern Yukon, Canada

    OpenAIRE

    Karlsson, Pia

    2014-01-01

    High mercury (Hg) levels have been measured in fish in Kusawa Lake (KL), a subalpine, partly glacier-fed lake situated in the southwestern Yukon, Canada, but it is presently unknown where this Hg comes from. One possible source may be atmospheric deposition of Hg in snow and subsequent release by melt into the lake. In this study, the amounts of total Hg (THg) deposited in sampled alpine snow and glacial ice from the KL catchment area were measured in order to quantify this input. Samples of ...

  15. CVD diamond deposition under atmospheric conditions on steel with a silicon intermediate layer

    OpenAIRE

    Prieske, Markus

    2016-01-01

    In order to realize dry metal forming, the requirements of the surface layer, e.g. to load-bearing capacity and tribological properties are increasing. Therefore, the feasibility of chemical vapour deposition (CVD) of diamond onto tool steel 1.2379 under atmospheric conditions without a vacuum chamber is investigated, so that there is no limit according to the size of the tool. For the deposition of CVD diamond coatings, a laser-based plasma CVD process combined with a physical vapour dep-osi...

  16. Use of mosses as biomonitors of atmospheric deposition of trace elements

    International Nuclear Information System (INIS)

    Some basic facts about the use of mosses as biomonitors of atmospheric trace element deposition are reviewed, and advantages and limitations of this approach are discussed, largely on the basis of experience from regular use of this technique in Norway over the last 20 years. Topics discussed include different versions of the moss technique, mechanisms and efficiencies of trace element uptake, conversion of concentrations in moss to bulk deposition rates, and contribution from sources other than air pollution to the elemental composition of different elements. Suggestions are presented for further work in order to extend the use of mosses as biomonitors. (author)

  17. The fine structure of niobium condensates deposited from ion-atomic fluxes in helium atmosphere

    International Nuclear Information System (INIS)

    Helium gas influence on the structural characteristics of niobium coatings deposited by low-energy metallic Nb ion-stoic fluxes in He atmosphere is investigated. It is shown that He implantation in Nb films during condensation is accompanied with the decreasing of the mean size of condensate grains. At the same time, He atoms modify no physical processes of the fine structure formation. Using thermodesorption spectroscopy we have determined that He atoms mainly belong to vacancy/vacancy-solute complexes in Nb coatings. Our conclusion is that such complexes play a dominant role in formation of the fine structure of vacuum coatings deposited from ion-atomic fluxes

  18. Long-term atmospheric deposition of nitrogen, phosphorus and sulfate in a large oligotrophic lake.

    Science.gov (United States)

    Ellis, Bonnie K; Craft, James A; Stanford, Jack A

    2015-01-01

    We documented significantly increasing trends in atmospheric loading of ammonium (NH4) and nitrate/nitrite (NO2/3) and decreasing trends in total phosphorus (P) and sulfate (SO4) to Flathead Lake, Montana, from 1985 to 2004. Atmospheric loading of NO2/3 and NH4 increased by 48 and 198% and total P and SO4 decreased by 135 and 39%. The molar ratio of TN:TP also increased significantly. Severe air inversions occurred periodically year-round and increased the potential for substantial nutrient loading from even small local sources. Correlations between our loading data and various measures of air quality in the basin (e.g., particulate matter dust and smoke are important sources. Ammonium was the primary form of N in atmospheric deposition, whereas NO3 was the primary N form in tributary inputs. Atmospheric loading of NH4 to Flathead Lake averaged 44% of the total load and on some years exceeded tributary loading. Primary productivity in the lake is colimited by both N and P most of the year; and in years of high atmospheric loading of inorganic N, deposition may account for up to 6.9% of carbon converted to biomass.

  19. Long-term atmospheric deposition of nitrogen, phosphorus and sulfate in a large oligotrophic lake

    Directory of Open Access Journals (Sweden)

    Bonnie K. Ellis

    2015-03-01

    Full Text Available We documented significantly increasing trends in atmospheric loading of ammonium (NH4 and nitrate/nitrite (NO2/3 and decreasing trends in total phosphorus (P and sulfate (SO4 to Flathead Lake, Montana, from 1985 to 2004. Atmospheric loading of NO2/3 and NH4 increased by 48 and 198% and total P and SO4 decreased by 135 and 39%. The molar ratio of TN:TP also increased significantly. Severe air inversions occurred periodically year-round and increased the potential for substantial nutrient loading from even small local sources. Correlations between our loading data and various measures of air quality in the basin (e.g., particulate matter <10 µm in size, aerosol fine soil mass, aerosol nutrient species, aerosol index, hectares burned suggest that dust and smoke are important sources. Ammonium was the primary form of N in atmospheric deposition, whereas NO3 was the primary N form in tributary inputs. Atmospheric loading of NH4 to Flathead Lake averaged 44% of the total load and on some years exceeded tributary loading. Primary productivity in the lake is colimited by both N and P most of the year; and in years of high atmospheric loading of inorganic N, deposition may account for up to 6.9% of carbon converted to biomass.

  20. ATMOSPHERIC DISPERSAL AND DEPOSITION OF TEPHRA FROM A POTENTIAL VOLCANIC ERUPTION AT YUCCA MOUNTAIN, NEVADA

    Energy Technology Data Exchange (ETDEWEB)

    C. Harrington

    2004-10-25

    The purpose of this model report is to provide documentation of the conceptual and mathematical model (Ashplume) for atmospheric dispersal and subsequent deposition of ash on the land surface from a potential volcanic eruption at Yucca Mountain, Nevada. This report also documents the ash (tephra) redistribution conceptual model. These aspects of volcanism-related dose calculation are described in the context of the entire igneous disruptive events conceptual model in ''Characterize Framework for Igneous Activity'' (BSC 2004 [DIRS 169989], Section 6.1.1). The Ashplume conceptual model accounts for incorporation and entrainment of waste fuel particles associated with a hypothetical volcanic eruption through the Yucca Mountain repository and downwind transport of contaminated tephra. The Ashplume mathematical model describes the conceptual model in mathematical terms to allow for prediction of radioactive waste/ash deposition on the ground surface given that the hypothetical eruptive event occurs. This model report also describes the conceptual model for tephra redistribution from a basaltic cinder cone. Sensitivity analyses and model validation activities for the ash dispersal and redistribution models are also presented. Analyses documented in this model report update the previous documentation of the Ashplume mathematical model and its application to the Total System Performance Assessment (TSPA) for the License Application (TSPA-LA) igneous scenarios. This model report also documents the redistribution model product outputs based on analyses to support the conceptual model. In this report, ''Ashplume'' is used when referring to the atmospheric dispersal model and ''ASHPLUME'' is used when referencing the code of that model. Two analysis and model reports provide direct inputs to this model report, namely ''Characterize Eruptive Processes at Yucca Mountain, Nevada and Number of Waste Packages Hit

  1. Characteristics Of Atmospheric Dry Deposition Of Metals To The Region Of Lake Asan And Sapgyo, Korea

    Science.gov (United States)

    Han, J.; Shin, H.; Lee, M.; Lim, Y.; Seo, M.; Jung, I.

    2008-12-01

    Environment includes a multi-media such as air, surface water, soil, underground water and ecosystem. Some pollutants transfer among a multi-media, posing serious threat to humans, animals and plants. Pollutants released into the environment remain for long times and transport long distances while going through physical and chemical interactions such as transports between multi-media ; air, water and soil, deposition, and absorption and release from organisms. This study assessed the amount of heavy metals transferred from air to water and soil using dry deposition plate and water surface sampler during spring (June 13 ~ 21, 2007) and winter (October 23 ~ 30 in 2007) at 9 locations including Dangjin, Pyeongtaek and Asan. Micro-Orifice Uniform Deposit Impactor, MOUDI was used to confirm the size distribution. The measured heavy metal deposition flux was compared with the expectation obtained with deposition model. In addition, amount of heavy metal deposition at Asan and Sapgyo lakes were evaluated to verify the water pollution state driven by atmospheric deposition. Atmospheric dry deposition flux of metals are 133.92 microgram m-2 day-1, 44.01 microgram m-2 day-1, 0.915 microgram m-2 day-1, and 0.175 microgram m-2 day-1 during spring, and 72.86 microgram m-2 day- 1, 88.14 microgram m-2 day-1, 0.991 microgram m-2 day-1, and 0.189 microgram m-2 day-1 during fall, for lead, nickel, arsenic, and cadmium, respectively. It is required to re- calculation the dry deposition flux by land use type due to possibility of underestimating the flux in case of using grease surrogate surface having low surface roughness. The cadmium, lead, and arsenic size distribution was mono-modal with the peaks in the 0.65 ~ 1.1 micrometer size range in the fine mode showing sharp peak in the condensation submode especially for cadmium and lead because of effect of primary emission. The nickel size distribution was bimodal, a typical size distribution for an urban atmosphere, showing sharp

  2. Mosses as biomonitors to study the atmospheric deposition of heavy metals over the territory of Slovakia

    International Nuclear Information System (INIS)

    In regional trace element studies it is advantageous to determine as many elements as possible in order to better distinguish between different source categories. In the present work the moss bio-monitoring technique and the combination of two analytical techniques - epithermal neutron activation analysis (ENAA) and flame atomic absorption spectrometry (AAS) - were applied to elucidate these problems. The total concentrations of 44 individual elements were determined in 86 samples of mosses. The mean, median, standard deviation and range values was determined for each elements. The use of terrestrial mosses as bio monitors is a well-established technique in Europe Comparison with the current median level in Norway shows strong pollution of the examined areas of Slovakia with the most of heavy metals. Strongly elevated Pb values with compare even South Ural Maintains is evident. The Cd value is 1.5 to 9 times higher than in other Europeans regions, only concentration of Zn are approximately equally. The most important feature of the sampling is that it correlates with the European Moss-Survey-2000, and the results obtained will be incorporated in the Atlas of Heavy Metal Atmospheric Deposition in Europe. (authors)

  3. Heavy Metals and Trace Elements Atmospheric Deposition Studies in Tula Region Using Moss Biomonitors Technique

    CERN Document Server

    Ermakova, E V; Steinnes, E

    2002-01-01

    For the first time the moss biomonitors technique was used in air pollution studies in Tula Region (Central Russia), applying NAA, AAS. Moss samples were collected at 83 sites in accordance with the sampling strategy adopted in European projects on biomonitoring atmospheric deposition. A wide set of trace elements in mosses was determined. The method of epithermal neutron activation at IBR-2 reactor of FLNP JINR has made it possible to identify 33 elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, As, Br, Rb, Sr, Mo, Sb, I, Cs, Ba, La, Ce, Sm, Tb, Yb, Hf, Ta, W, Th, U) in the large-scale concentration range - from 10000 ppm for K to 0,001 ppm for Tb and Ta. Cu, Cd and Pb were determined by the flame AAS in the Norwegian Institute of Science and Technology. Using the graphical technique and principal component analysis allowed to separate plant, crustal and general pollution components in the moss. The obtained data will be used for constructing coloured maps of the distribution of elements over t...

  4. Subalpine grassland carbon balance during 7 years of increased atmospheric N deposition

    Science.gov (United States)

    Volk, Matthias; Enderle, Jan; Bassin, Seraina

    2016-07-01

    Air pollution agents interact when affecting biological sinks for atmospheric CO2, e.g., the soil organic carbon (SOC) content of grassland ecosystems. Factors favoring plant productivity, like atmospheric N deposition, are usually considered to favor SOC storage. In a 7-year experiment in subalpine grassland under N- and O3-deposition treatment, we examined C fluxes and pools. Total N deposition was 4, 9, 14, 29 and 54 kg N ha-1 yr-1 (N4, N9, etc.); annual mean phytotoxic O3 dose was 49, 65 and 89 mmol m-2 projected leaf area. We hypothesized that between years SOC of this mature ecosystem would not change in control treatments and that effects of air pollutants are similar for plant yield, net ecosystem productivity (NEP) and SOC content, leading to SOC content increasing with N deposition. Cumulative plant yield showed a significant N and N × N effect (+38 % in N54) but no O3 effect. In the control treatment SOC increased significantly by 9 % in 7 years. Cumulative NEP did show a strong, hump-shaped response pattern to N deposition with a +62 % increase in N14 and only +39 % increase in N54 (N effect statistically not significant, N × N interaction not testable). SOC had a similar but not significant response to N, with highest C gains at intermediate N deposition rates, suggesting a unimodal response with a marginal (P = 0.09) N × N interaction. We assume the strong, pollutant-independent soil C sink developed as a consequence of the management change from grazing to cutting. The non-parallel response of SOC and NEP compared to plant yield under N deposition is likely the result of increased respiratory SOC losses, following mitigated microbial N-limitation or priming effects, and a shift in plant C allocation leading to smaller C input from roots.

  5. Atmospheric deposition of N, P and Fe to the Northern Indian Ocean: implications to C- and N-fixation.

    Science.gov (United States)

    Srinivas, Bikkina; Sarin, M M

    2013-07-01

    This study presents the first data set on atmospheric input of N, P and Fe to the Northern Indian Ocean. Based on the chemical analysis of ambient aerosols, collected from the marine atmospheric boundary layer (MABL) during the continental outflow (January-April), we document that dry-deposition fluxes (μmolm(-2) d(-1)) of N (2-167), P (0.5-4.8) and Fe (0.02-1.2) to the Bay of Bengal are significantly higher compared to those over the Arabian Sea [N: 0.2-18.6; P: 0.3-0.9; Fe: 0.001-0.015]. Using atmospherically derived P and Fe, C-fixation (1.1 Pg yr(-1)) in the Bay of Bengal is dominated by anthropogenic sources. In contrast, C-fixation (0.03 Pg yr(-1)) in the Arabian Sea is limited by P and Fe. This is attributed to the poor fractional solubility of atmospheric mineral dust transported to the Arabian Sea. However, N-fixation by diazotrophs in the two oceanic regions is somewhat similar (0.5 Tg yr(-1)). Our estimate of N-deposition (0.2 Tg yr(-1)) to the Northern Indian Ocean is significantly lower compared to model results (~800-1200 mg-Nm(-2)yr(-1)≈5.7-8.6 Tg yr(-1) by Duce et al. (2008); ~4.1 Tg yr(-1) by Okin et al. (2011); ~0.8 Tg yr(-1) by Kanakidou et al. (2012)). An overestimate of N-deposition by models could arise due to inappropriate parameterization of temporal variability associated with the continental outflow spread over only four months.

  6. In Search of Patagonian Dust: Atmospheric Deposition of Micronutrients to the Southern Atlantic

    Science.gov (United States)

    Chance, R.; Baker, A. R.; Jickells, T. D.

    2012-12-01

    Atmospheric inputs constitute a low but variable source of micronutrients to the south Atlantic and Southern Ocean, the magnitude and spatial distribution of which remains poorly constrained. In particular, dust arising from the arid parts of southern South America has been identified as a potentially significant source of micronutrients. Ice core records indicate large fluctuations in Patagonian dust supply over glacial-interglacial timescales, but little is known about modern day fluxes. As part of the UK-GEOTRACES program, atmospheric aerosol was simultaneously sampled in the eastern and western basins of the southern Atlantic downwind of Patagonia. Specifically, a new time-series station for monitoring atmospheric aerosol in the western south Atlantic was established at Carcass Island (51o15' S, 60o35' W) in the Falkland Islands, in September 2010, and shipboard aerosol and rain samples were collected in the region between Cape Town, South Africa, and 40oS, 5oW in November and December 2010 (cruise D357). Sampling at Carcass Island continued during the austral summer of 2011-2012, and in January 2012 a second shipboard transect across the Atlantic at 40oS was completed (cruise JC068). Here we compare atmospheric concentrations and wet and dry deposition fluxes for trace metals and major nutrients in the two basins are compared, and use principal component analysis to investigate qualitative differences in the overall composition of aerosol from different sources. Concentrations of aerosol nitrogen were higher at Carcass Island than in the eastern Atlantic. During cruise D357, median concentrations of 1.7 nmol m-3 nitrate and 2.0 nmol m-3 ammonium were observed, consistent with remote south Atlantic air, while on Carcass Island corresponding concentrations were 2.3 and 6.3 nmol m-3 during the first year of sampling. Differences in the isotopic composition of aerosol nitrate from the two campaigns are discussed. "Soluble" trace metals were operationally defined

  7. Nitrogen accumulation and partitioning in a High Arctic tundra ecosystem from extreme atmospheric N deposition events.

    Science.gov (United States)

    Choudhary, Sonal; Blaud, Aimeric; Osborn, A Mark; Press, Malcolm C; Phoenix, Gareth K

    2016-06-01

    Arctic ecosystems are threatened by pollution from recently detected extreme atmospheric nitrogen (N) deposition events in which up to 90% of the annual N deposition can occur in just a few days. We undertook the first assessment of the fate of N from extreme deposition in High Arctic tundra and are presenting the results from the whole ecosystem (15)N labelling experiment. In 2010, we simulated N depositions at rates of 0, 0.04, 0.4 and 1.2 g Nm(-2)yr(-1), applied as (15)NH4(15)NO3 in Svalbard (79(°)N), during the summer. Separate applications of (15)NO3(-) and (15)NH4(+) were also made to determine the importance of N form in their retention. More than 95% of the total (15)N applied was recovered after one growing season (~90% after two), demonstrating a considerable capacity of Arctic tundra to retain N from these deposition events. Important sinks for the deposited N, regardless of its application rate or form, were non-vascular plants>vascular plants>organic soil>litter>mineral soil, suggesting that non-vascular plants could be the primary component of this ecosystem to undergo measurable changes due to N enrichment from extreme deposition events. Substantial retention of N by soil microbial biomass (70% and 39% of (15)N in organic and mineral horizon, respectively) during the initial partitioning demonstrated their capacity to act as effective buffers for N leaching. Between the two N forms, vascular plants (Salix polaris) in particular showed difference in their N recovery, incorporating four times greater (15)NO3(-) than (15)NH4(+), suggesting deposition rich in nitrate will impact them more. Overall, these findings show that despite the deposition rates being extreme in statistical terms, biologically they do not exceed the capacity of tundra to sequester pollutant N during the growing season. Therefore, current and future extreme events may represent a major source of eutrophication. PMID:26956177

  8. Atmospheric dry deposition of inorganic and organic nitrogen to the Bay of Bengal: Impact of continental outflow

    Digital Repository Service at National Institute of Oceanography (India)

    Srinivas, B.; Sarin, M.M.; Sarma, V.V.S.S.

    in the deep freezer at - 19 0 C until the time of analysis. The mass concentrations of PM 2.5 and PM 10 were obtained gravimetrically by measuring the weight of the filters, before and after the collection. All samples were handled under a clean laminar-flow..., including organic nitrogen (N Org ), are bio-available (Bronk et al., 2007; Duce et al., 2008; Jickells, 2006; Seitzinger and Sanders, 1999; Spokes et al., 2000). As a result, studies on atmospheric deposition needs to be extended to measure organic...

  9. Deposition and microstructure characterization of atmospheric plasma-sprayed ZnO coatings for NO2 detection

    International Nuclear Information System (INIS)

    This work studied the possibility of using a sensor based on plasma-sprayed zinc oxide (ZnO) sensitive layer for NO2 detection. The atmospheric plasma spray process was employed to deposit ZnO gas sensing layer and the obtained coating structure was characterized by scanning electron microscopy and X-ray diffraction analysis. The influences of gas concentration, working temperature, water vapor in testing air on NO2 sensing performance of the ZnO sensors were studied. ZnO sensors showed a good sensor response and selectivity to NO2 at an optimal working temperature.

  10. Atmospheric Deposition of Pb, Zn, Cu, and Cd in Amman, Jordan

    International Nuclear Information System (INIS)

    Atmospheric samples were collected by high-volume air sampler and dust fall containers during the summer of 1995 at different sites in Amman City, Jordan. Heavy metal contents in settle able (dust fall) as well as in air particulates (suspended) were analyzed by graphite furnace atomic absorption spectrophotometry. The atmospheric concentrations of Zn, Cu, Pb, and Cd were 344, 170, 291, and 3.8 ng/m3 , respectively. On the other hand, the levels of these elements in dust fall deposition were 505, 94, 74, and 3.1 μg/g, respectively. The fluxes and dry deposition velocities of these heavy metals were determined and compared with the findings of other investigators worldwide. Significant enrichment coefficients of heavy metals in dust fall were observed. The enrichment coefficients were 12.1, 6.1, 11.7, and 1.1 for Zn, Cu, Pb, and Cd, respectively

  11. Atmospheric deposition and surface stratification as controls of contrasting chlorophyll abundance in the North Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Patra, P.K.; DileepKumar, M.; Mahowald, N.; Sarma, V.V.S.S.

    this limitation [Measures and Vink, 1999]. Though dissolved Fe brought from the subsurface waters by upwelling might support biological activity to some extent, the aeolian Fe supply supplements the requirement; the importance of which actually increases from... et al.: Contrasts of Arabian Sea and Bay of Bengal J. Geophys. Res. ? Ocean 14 supplemented by atmospheric dust deposition. During the OND months both the oceanic basins receive low inputs of land-originated aerosols as seen from the aerosol index...

  12. Recent atmospheric dust deposition in an ombrotrophic peat bog in Great Hinggan Mountain, Northeast China.

    Science.gov (United States)

    Bao, Kunshan; Xing, Wei; Yu, Xiaofei; Zhao, Hongmei; McLaughlin, Neil; Lu, Xianguo; Wang, Guoping

    2012-08-01

    Recent deposition of atmospheric soil dust (ASD) was studied using (210)Pb-dated Sphagnum-derived peat sequences from Great Hinggan Mountain in northeast China. Physicochemical indices of peat including dry bulk density, water content, ash content, total organic carbon and mass magnetic susceptibility were measured. Acid-insoluble concentration of lithogenic metals (Al, Ca, Fe, Mn, V and Ti) were measured using ICP-AES. The basic physicochemical properties were used to assess the peat trophic status and indicated that the sections above 45-60 cm are rain-fed peat. A continuous record of ASD fluxes over the past 150 years was reconstructed based on the geochemical data obtained from the ombrotrophic zone, and the average input rate of ASD is 13.4-68.1 g m(-2) year(-1). The source of soil dust deposited in peat was dominated by the long-range transport of mineral aerosol from the drylands in north China and Mongolia. The temporal variation of ASD fluxes in the last 60 years coincides well with the meteorological records of dust storm frequency during 1954-2002 in north China. This suggests that the reconstructed sequence of atmospheric dust deposition is reliable and we can look back in time at the dust evolution before 1949. Dust storm events were observed occasionally in the late Qing dynasty, and their frequency and intensity were smaller than dust weather occurring in recent times. Four peaks of ASD fluxes were distinguished and correlated with the historical events at that time. This study presents the first atmospheric soil dust data in peat records in northeast China, and complements a global database of peat bog archives of atmospheric deposition. The results reflect the patterns of local environmental change over the past century in north China and will be helpful in formulating policies to achieve sustainable and healthy development.

  13. Heavy Metal Determination in Atmospheric Deposition and Other Fluxes in Northern France Agrosystems

    OpenAIRE

    Azimi, Sam; Cambier, Philippe; Lecuyer, Isabelle; Thevenot, Daniel,

    2004-01-01

    International audience The aim of this study is to assess the annual balance of the fluxes of Cd, Cu, Ni, Pb and Zn within different cropping systems, in an experimental site located near Versailles, France. Four fluxes through the cultivated horizon were considered to assess the annual heavy metal balance in these systems: 1) atmospheric depositions, 2) fertilisers as inputs, 3) crops and 4) leaching water as outputs. The water mass flow was estimated with a model (CERES) while the other ...

  14. Time Invariant Surface Roughness Evolution during Atmospheric Pressure Thin Film Depositions

    OpenAIRE

    Thomas Merkh; Robert Spivey; Toh Ming Lu

    2016-01-01

    The evolution of thin film morphology during atmospheric pressure deposition has been studied utilizing Monte Carlo methods. Time invariant root-mean-squared roughness and local roughness morphology were both observed when employing a novel simulation parameter, modeling the effect of the experimental high pressure condition. This growth regime, where the surface roughness remains invariant after reaching a critical value, has not been classified by any existing universality class. An anti-sh...

  15. A European survey of atmospheric heavy metal deposition in 2000-2001

    International Nuclear Information System (INIS)

    The background, administration and current status of the monitoring programme 'European Survey of Atmospheric Heavy Metal Deposition' is described. All European states are invited to join the survey 2000- 2001. The co-ordination and responsibility for the survey will gradually be transferred from the Nordic Council of Ministers to the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops (ICP Vegetation). (author)

  16. Recent atmospheric dust deposition in an ombrotrophic peat bog in Great Hinggan Mountain, Northeast China.

    Science.gov (United States)

    Bao, Kunshan; Xing, Wei; Yu, Xiaofei; Zhao, Hongmei; McLaughlin, Neil; Lu, Xianguo; Wang, Guoping

    2012-08-01

    Recent deposition of atmospheric soil dust (ASD) was studied using (210)Pb-dated Sphagnum-derived peat sequences from Great Hinggan Mountain in northeast China. Physicochemical indices of peat including dry bulk density, water content, ash content, total organic carbon and mass magnetic susceptibility were measured. Acid-insoluble concentration of lithogenic metals (Al, Ca, Fe, Mn, V and Ti) were measured using ICP-AES. The basic physicochemical properties were used to assess the peat trophic status and indicated that the sections above 45-60 cm are rain-fed peat. A continuous record of ASD fluxes over the past 150 years was reconstructed based on the geochemical data obtained from the ombrotrophic zone, and the average input rate of ASD is 13.4-68.1 g m(-2) year(-1). The source of soil dust deposited in peat was dominated by the long-range transport of mineral aerosol from the drylands in north China and Mongolia. The temporal variation of ASD fluxes in the last 60 years coincides well with the meteorological records of dust storm frequency during 1954-2002 in north China. This suggests that the reconstructed sequence of atmospheric dust deposition is reliable and we can look back in time at the dust evolution before 1949. Dust storm events were observed occasionally in the late Qing dynasty, and their frequency and intensity were smaller than dust weather occurring in recent times. Four peaks of ASD fluxes were distinguished and correlated with the historical events at that time. This study presents the first atmospheric soil dust data in peat records in northeast China, and complements a global database of peat bog archives of atmospheric deposition. The results reflect the patterns of local environmental change over the past century in north China and will be helpful in formulating policies to achieve sustainable and healthy development. PMID:22664536

  17. Estimation of aquifer recharge by means of atmospheric chloride deposition balance

    OpenAIRE

    Custodio Gimena, Emilio

    2010-01-01

    The measurement of the atmospheric chloride deposition on land allows the estimation of long-term average aquifer recharge when the average chloride content in the recharge water is known. This is a well-established, simple method, although not exempt from theoretical and practical difficulties. In spite of its potential, it is seldom applied. Under favorable circumstances, the results are reliable and the associated uncertainty can be determined. The chloride content of recharge water ...

  18. Atmospheric deposition in an urban area: Implications for assessing the effects of hazardous air pollutants

    OpenAIRE

    Bouzonville, Adrien; Elsass, Philippe; Elsass, Francoise; Atkins, Sharon

    2011-01-01

    Pollutants emitted to the atmosphere in urban areas have indirect effects through deposition onto the ground, which, over time, could negatively affect the quality of soil, plants, water and groundwater. In this baseline study, evaluation of topsoil contamination in an urban area of France has been carried out to correlate concentrations observed in the soil with the local air emission sources. The analytical program is an extensive study carried out over a 200 km2 area and the results confir...

  19. Atmospheric deposition of PCDD/Fs measured via automated and traditional samplers in Northern Taiwan.

    Science.gov (United States)

    Chi, Kai Hsien; Liu, Kung Ting; Chang, Shu Hao; Chang, Moo Been

    2009-11-01

    Most polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the atmosphere are bound to particles which are suspended in the atmosphere, and eventually settle on soil, vegetation, water bodies or other receptors in the environment. Monitoring atmospheric deposition fluxes (dry/wet) is important in tracing the environmental fate and behavior of PCDD/Fs. PCDD/F depositions were collected via an automated PCDD/F ambient sampler and traditional cylindrical vessels, respectively, from April 2007 to February 2008. The automated PCDD/F ambient sampler used in this study can prevent both re-suspension and photo degradation of the PCDD/Fs collected and effectively separates the PCDD/F samples into dry and wet contributions. The results indicated that the ambient PCDD/F concentrations collected using the PS-1 sampler ranged from 0.02 pg I-TEQ/m(3) to 0.16 pg I-TEQ/m(3) in Northern Taiwan. The results also indicated that the PCDD/F deposition flux collected using the automated PCDD/F sampler (17.5 pg I-TEQ/m(2) d to 25.8 pg I-TEQ/m(2) d) was significantly higher than that sampled with the cylindrical vessels (2.0 pg I-TEQ/m(2) d to 9.9 pg I-TEQ/m(2) d). The difference was attributed to the fact that part of the PCDD/F depositions collected using the traditional cylindrical vessels had undergone photo degradation and evaporation. In addition, the wet deposition flux of PCDD/Fs (39.4 pg I-TEQ/m(2) rainy day to 228 pg I-TEQ/m(2) rainy day) observed in this study was significantly higher than the dry deposition flux (12.3 pg I-TEQ/m(2) sunny day to 16.7 pg I-TEQ/m(2) sunny day). These results demonstrated that wet deposition is the major PCDD/F removal mechanism in the atmosphere. PMID:19819518

  20. Tipping point analysis of atmospheric oxygen concentration

    Energy Technology Data Exchange (ETDEWEB)

    Livina, V. N.; Forbes, A. B. [National Physical Laboratory, Teddington TW11 0LW (United Kingdom); Vaz Martins, T. M. [John Innes Centre, Norwich NR4 7UH (United Kingdom)

    2015-03-15

    We apply tipping point analysis to nine observational oxygen concentration records around the globe, analyse their dynamics and perform projections under possible future scenarios, leading to oxygen deficiency in the atmosphere. The analysis is based on statistical physics framework with stochastic modelling, where we represent the observed data as a composition of deterministic and stochastic components estimated from the observed data using Bayesian and wavelet techniques.

  1. Benefits of deposition reduction for nature management; a nation-wide assessment of the relation between atmospheric deposition, ecological quality and avoidable management costs

    NARCIS (Netherlands)

    Jong, de J.J.; Wamelink, G.W.W.; Dobben, van H.F.; Wijk, van M.N.

    2004-01-01

    Alterra was commissioned by the Dutch Ministry of Housing, Spatial Planning and the Environment (VROM) to estimate the additional costs made by nature reserve managers to mitigate the effects of atmospheric deposition. The costs of increasing deposition levels - or the benefits of reducing depositio

  2. Response of stable carbon isotope in epilithic mosses to atmospheric nitrogen deposition

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xueyan, E-mail: liuxueyan@vip.skleg.c [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Xiao Huayun; Liu Congqiang [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Li Youyi; Xiao Hongwei; Wang Yanli [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Graduate University of Chinese Academy of Sciences, Yuquanlu, Beijing 100049 (China)

    2010-06-15

    Epilithic mosses are characterized by insulation from substratum N and hence meet their N demand only by deposited N. This study investigated tissue C, total Chl and delta{sup 13}C of epilithic mosses along 2 transects across Guiyang urban (SW China), aiming at testing their responses to N deposition. Tissue C and total Chl decreased from the urban to rural, but delta{sup 13}C{sub moss} became less negative. With measurements of atmospheric CO{sub 2} and delta{sup 13}CO{sub 2}, elevated N deposition was inferred as a primary factor for changes in moss C and isotopic signatures. Correlations between total Chl, tissue C and N signals indicated a nutritional effect on C fixation of epilithic mosses, but the response of delta{sup 13}C{sub moss} to N deposition could not be clearly differentiated from effects of other factors. Collective evidences suggest that C signals of epilithic mosses are useful proxies for N deposition but further works on physiological mechanisms are still needed. - Photosynthetic {sup 13}C discrimination of bryophytes might increase with elevated N deposition.

  3. Characterisation of atmospheric deposited particles during a dust storm in urban areas of Eastern Australia.

    Science.gov (United States)

    Gunawardena, Janaka; Ziyath, Abdul M; Bostrom, Thor E; Bekessy, Lambert K; Ayoko, Godwin A; Egodawatta, Prasanna; Goonetilleke, Ashantha

    2013-09-01

    The characteristics of dust particles deposited during the 2009 dust storm in the Gold Coast and Brisbane regions of Australia are discussed in this paper. The study outcomes provide important knowledge in relation to the potential impacts of dust storm related pollution on ecosystem health in the context that the frequency of dust storms is predicted to increase due to anthropogenic desert surface modifications and climate change impacts. The investigated dust storm contributed a large fraction of fine particles to the environment with an increased amount of total suspended solids, compared to dry deposition under ambient conditions. Although the dust storm passed over forested areas, the organic carbon content in the dust was relatively low. The primary metals present in the dust storm deposition were aluminium, iron and manganese, which are common soil minerals in Australia. The dust storm deposition did not contain significant loads of nickel, cadmium, copper and lead, which are commonly present in the urban environment. Furthermore, the comparison between the ambient and dust storm chromium and zinc loads suggested that these metals were contributed to the dust storm by local anthropogenic sources. The potential ecosystem health impacts of the 2009 dust storm include, increased fine solids deposition on ground surfaces resulting in an enhanced capacity to adsorb toxic pollutants as well as increased aluminium, iron and manganese loads. In contrast, the ecosystem health impacts related to organic carbon and other metals from dust storm atmospheric deposition are not considered to be significant.

  4. Deposition and retention of air pollutants on vegetation and other atmospheric interfaces

    International Nuclear Information System (INIS)

    The question of the deposition of aerosols and gases are applied to biological and ecological problems concerning the filtering aspect of atmospheric interfaces, especially vegetation, with respect to air pollution, and also the resulting pollutant effect. In order to determine the deposition of aerosols, numerous field experiments were carried out. The deposition of gases was treated on the basis of current literature data. The experiments indicate that the deposition of aerosols on grass largely depends on aerosol diameter, dry weight per unit area and the wind velocity or turbulence of the air layer near the ground. Of the interfaces studied, namely soil without vegetation, water, filter paper, smooth and structured metals, grass, clover and trees, the latter had the greatest dust collecting capability. It is recommended that in the afforestation of areas in the close proximity of industrial regions the common beech, silver birch and Japanese larch should be taken into particular consideration due to their great deposition effectiveness with respect to dusts and their comparatively high resistance to pollutant gases. Silver birch and moreover red horse chestnut should be considered for filtering the air in urban regions because of the high aerosol deposition. (orig./HP)

  5. Characterisation of atmospheric deposited particles during a dust storm in urban areas of Eastern Australia.

    Science.gov (United States)

    Gunawardena, Janaka; Ziyath, Abdul M; Bostrom, Thor E; Bekessy, Lambert K; Ayoko, Godwin A; Egodawatta, Prasanna; Goonetilleke, Ashantha

    2013-09-01

    The characteristics of dust particles deposited during the 2009 dust storm in the Gold Coast and Brisbane regions of Australia are discussed in this paper. The study outcomes provide important knowledge in relation to the potential impacts of dust storm related pollution on ecosystem health in the context that the frequency of dust storms is predicted to increase due to anthropogenic desert surface modifications and climate change impacts. The investigated dust storm contributed a large fraction of fine particles to the environment with an increased amount of total suspended solids, compared to dry deposition under ambient conditions. Although the dust storm passed over forested areas, the organic carbon content in the dust was relatively low. The primary metals present in the dust storm deposition were aluminium, iron and manganese, which are common soil minerals in Australia. The dust storm deposition did not contain significant loads of nickel, cadmium, copper and lead, which are commonly present in the urban environment. Furthermore, the comparison between the ambient and dust storm chromium and zinc loads suggested that these metals were contributed to the dust storm by local anthropogenic sources. The potential ecosystem health impacts of the 2009 dust storm include, increased fine solids deposition on ground surfaces resulting in an enhanced capacity to adsorb toxic pollutants as well as increased aluminium, iron and manganese loads. In contrast, the ecosystem health impacts related to organic carbon and other metals from dust storm atmospheric deposition are not considered to be significant. PMID:23712117

  6. Atmospheric Nitrogen Deposition to the Oceans: Observation- and Model-Based Estimates

    Science.gov (United States)

    Baker, Alex

    2016-04-01

    The reactive nitrogen (Nr) burden of the atmosphere has been increased by a factor of 3-4 by anthropogenic activity since the Industrial Revolution. This has led to large increases in the deposition of nitrate and ammonium to the surface waters of the open ocean, particularly downwind of major human population centres, such as those in North America, Europe and Southeast Asia. In oligotrophic waters, this deposition has the potential to significantly impact marine productivity and the global carbon cycle. Global-scale understanding of N deposition to the oceans is reliant on our ability to produce effective models of reactive nitrogen emission, atmospheric chemistry, transport and deposition (including deposition to the land surface). Over land, N deposition models can be assessed using comparisons to regional monitoring networks of precipitation chemistry (notably those located in North America, Europe and Southeast Asia). No similar datasets exist which would allow observation - model comparisons of wet deposition for the open oceans, because long-term wet deposition records are available for only a handful of remote island sites and rain collection over the open ocean itself is logistically very difficult. In this work we attempt instead to use ~2800 observations of aerosol nitrate and ammonium concentrations, acquired from sampling aboard ships in the period 1995 - 2012, to assess the performance of modelled N deposition fields over the remote ocean. This database is non-uniformly distributed in time and space. We selected three ocean regions (the eastern tropical North Atlantic, the northern Indian Ocean and northwest Pacific) where we considered the density and distribution of observational data is sufficient to provide effective comparison to the model ensemble. Our presentation will focus on the eastern tropical North Atlantic region, which has the best data coverage of the three. We will compare dry deposition fluxes calculated from the observed nitrate

  7. Volcano emissions of trace metals, atmospheric deposition, and supply to biogeochemical cycles

    Science.gov (United States)

    Hinkley, T.; Thornber, C. R.; Matsumoto, A.

    2003-12-01

    Quiescently degassing (not exploding) volcanoes inject into the troposphere plumes that have remarkably high concentrations of ordinarily-rare, volatile trace metals. In pre-industrial times, these emissions appear to have accounted for the strong "enrichments" (relative to concentrations in crustal material or in ocean solute) of many such trace metals in the material deposited from the atmosphere. This has been shown by measuring the source strength of the emissions of metals from volcanoes, and comparing that to the amounts of the metals (excess over amounts accounted for by rock dust and sea salt) deposited onto high-latitude ice sheets: volcano degassing outputs of metals and deposition masses of metals to ice are comparable, on the basis of the masses (fluxes) and proportions of the metals, and from the proportions of lead (Pb) isotopes. There is indication that in modern industrial times the elevated trace metal fractions in the atmospheric material that has small particle size and long atmospheric residence time is still more strongly influenced by volcano emissions than by industrial emissions. Throughout earth's history it is likely that volcano emissions were a major control on the environmental background levels of trace elements, in which plants and animals evolved their tolerances to these mostly-poisonous substances.

  8. Atmospheric transport and deposition of mineral dust to the ocean: implications for research needs.

    Science.gov (United States)

    Schulz, Michael; Prospero, Joseph M; Baker, Alex R; Dentener, Frank; Ickes, Luisa; Liss, Peter S; Mahowald, Natalie M; Nickovic, Slobodan; García-Pando, Carlos Pérez; Rodríguez, Sergio; Sarin, Manmohan; Tegen, Ina; Duce, Robert A

    2012-10-01

    This paper reviews our knowledge of the measurement and modeling of mineral dust emissions to the atmosphere, its transport and deposition to the ocean, the release of iron from the dust into seawater, and the possible impact of that nutrient on marine biogeochemistry and climate. Of particular concern is our poor understanding of the mechanisms and quantities of dust deposition as well as the extent of iron solubilization from the dust once it enters the ocean. Model estimates of dust deposition in remote oceanic regions vary by more than a factor of 10. The fraction of the iron in dust that is available for use by marine phytoplankton is still highly uncertain. There is an urgent need for a long-term marine atmospheric surface measurement network, spread across all oceans. Because the southern ocean is characterized by large areas with high nitrate but low chlorophyll surface concentrations, that region is particularly sensitive to the input of dust and iron. Data from this region would be valuable, particularly at sites downwind from known dust source areas in South America, Australia, and South Africa. Coordinated field experiments involving both atmospheric and marine measurements are recommended to address the complex and interlinked processes and role of dust/Fe fertilization on marine biogeochemistry and climate.

  9. Impact of atmospheric wet deposition on phytoplankton community structure in the South China Sea

    Science.gov (United States)

    Cui, Dong-Yang; Wang, Jiang-Tao; Tan, Li-Ju; Dong, Ze-Yi

    2016-05-01

    The South China Sea (SCS), which is the largest marginal sea in East Asia, plays a significant role in regional climate change. However, research on the phytoplankton community structure (PCS) response to atmospheric wet deposition remains inadequate. In this study, field incubation experiments were performed to survey the impact of atmospheric wet deposition on the PCS in the SCS in December 2013. Results indicate that the mean dissolved inorganic nitrogen/dissolved inorganic phosphorous (DIN/DIP) ratio in rainwater was 136, which was higher than that in seawater. Under low initial nutrient concentrations, rainwater inputs not only significantly increased total chlorophyll a (Chl a) concentrations but also potentially altered the PCS. The total Chl a concentration increased 1.7-, 1.9-, and 1.6-fold; microphytoplankton increased 2.6-, 3.2-, and 1.7-fold with respect to their initial values in the 5%, 10% addition, and 10% addition (filtered) treatment samples, respectively. Finally, microphytoplankton contributed 61% to the total Chl a concentration in 10% addition treatment samples. Differences in the nutrients induced by atmospheric wet deposition resulted in a shift in the advantage from picophytoplankton to microphytoplankton. Diatoms became the predominant species, accounting for 55% of the total abundance after rainwater addition.

  10. Uncertainty and perspectives in studies of atmospheric nitrogen deposition in China: A response to Liu et al. (2015).

    Science.gov (United States)

    He, Nianpeng; Zhu, Jianxing; Wang, Qiufeng

    2015-07-01

    In this paper, we have formally responded to the speculation in "Liu et al. suspect that Zhu et al. (2015) may have underestimated dissolved organic N but overestimated total particulate N in wet deposition in China" by Liu et al. (2015). Here, we first discussed the uncertainty and plausible reasons of atmospheric deposition in China, which have been reported in different studies. We disagree with their interpretation on some points. Firstly, the difficulties in quality control from sampling to analyzing are common to all studies regarding atmospheric deposition, including the studies cited by Liu et al. (2015). More importantly, their discussion did not fully consider the apparent influence of different scaling-up methods (from an observation site scale to a national scale) on estimations of atmospheric N deposition in China. Furthermore, we provided the optimal approaches to resolve these challenges discussed in order to promote the related studies of atmospheric N deposition in China in the future.

  11. Atmospheric deposition and soil vertical distribution of 7Be in a semiarid region of central Argentina

    International Nuclear Information System (INIS)

    Beryllium-7 is a potentially powerful tracer of soil erosion but poor information on 7Be atmospheric deposition and associated soil inventories in a semiarid region of Central Argentina exists. We estimated the 7Be atmospheric wet deposition and 7Be inventory in undisturbed soils north of the City of San Luis (S 33 deg. 9'; W 66 deg. 16') and explored its seasonal variation. Rain and soil samples were collected during 2006-2008 and 2009-2012, respectively. The atmospheric wet deposition was estimated considering both the mean activity concentration in rainwater and the precipitation regime of the region. Using the assessed monthly wet deposition of 7Be, the expected 7Be areal activity in soil was estimated applying a simple model. These estimated values were confronted with the experimental measurements in soil. The 7Be rainwater activity concentration ranged from 0.7 to 3.2 Bq l-1, with a mean of 1.7 Bq l-1 (sd = 0.53 Bq l-1). A good linear relationship between 7Be wet deposition and rain magnitude was obtained (R=0.92, p-2 with a mean value of 32.7 Bq m-2 (sd = 29.9 Bq m-2). The annual depositional flux was estimated at 1140 ± 120 Bq m-2 y-1. The 7Be mass activity (Bq kg-1) values in soil samples in the wet period (November-April) were higher than in the dry period (May-October). A typical decreasing exponential function of 7Be areal activity (Bq m-2) with soil mass depth (kg m-2) was found and the distribution parameters for each month were determined. The minimum value of areal activity was 51 Bq m-2 in August, reaching the maximum of 438 Bq m-2 in February. The relaxation mass depth ranged from 2.9 kg m-2 in March to 1.3 kg m-2 in August. The confrontation of experimental measurements in soil with the estimated values using the model showed a good agreement. 7Be wet deposition explains the 7Be inventory in soil, but little differences detected for summer months could be explained by the runoff caused by heavy rains. During the wind season (September and

  12. Diamond synthesis at atmospheric pressure by microwave capillary plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Polycrystalline diamond has been synthesized on silicon substrates at atmospheric pressure, using a microwave capillary plasma chemical vapor deposition technique. The CH4/Ar plasma was generated inside of quartz capillary tubes using 2.45 GHz microwave excitation without adding H2 into the deposition gas chemistry. Electronically excited species of CN, C2, Ar, N2, CH, Hβ, and Hα were observed in the emission spectra. Raman measurements of deposited material indicate the formation of well-crystallized diamond, as evidenced by the sharp T2g phonon at 1333 cm−1 peak relative to the Raman features of graphitic carbon. Field emission scanning electron microscopy images reveal that, depending on the growth conditions, the carbon microstructures of grown films exhibit “coral” and “cauliflower-like” morphologies or well-facetted diamond crystals with grain sizes ranging from 100 nm to 10 μm

  13. Atmospheric depositions of 210Pb and 210Po in Lisbon, Portugal

    International Nuclear Information System (INIS)

    The long lived radon daughters 210Pb and 210Po were determined in samples of total surface deposition obtained with collectors continuously operated during 5 years, near Lisbon. The annual 210Pb flux was 66±12 Bqm-2, and the average annual 210Po flux was 8±3 Bq m-2, with an overall 210Po/210Pb activity ratio of 0.15±0.06. The deposition of 210Pb was positively correlated with seasonal rainfall, while 210Po was mainly originated in soil particles re-suspension throughout the year and also in seasonal forest fires. Unusually high 210Po/210Pb activity ratios, higher than unity, were occasionally recorded and the sources and causes are discussed. Long time-series of 210Pb and 210Po deposition fluxes, as presented herein, are rare although essential to test and constrain parameter of the atmospheric Global Circulation Models. (author)

  14. Atmospheric Plasma Deposition of SiO2 Films for Adhesion Promoting Layers on Titanium

    Directory of Open Access Journals (Sweden)

    Liliana Kotte

    2014-12-01

    Full Text Available This paper evaluates the deposition of silica layers at atmospheric pressure as a pretreatment for the structural bonding of titanium (Ti6Al4V, Ti15V3Cr3Sn3Al in comparison to an anodizing process (NaTESi process. The SiO2 film was deposited using the LARGE plasma source, a linearly extended DC arc plasma source and applying hexamethyldisiloxane (HMDSO as a precursor. The morphology of the surface was analyzed by means of SEM, while the characterization of the chemical composition of deposited plasma layers was done by XPS and FTIR. The long-term durability of bonded samples was evaluated by means of a wedge test in hot/wet condition. The almost stoichiometric SiO2 film features a good long-term stability and a high bonding strength compared to the films produced with the wet-chemical NaTESi process.

  15. Atmospheric mercury deposition recorded in an ombrotrophic peat core from Xiaoxing'an Mountain, Northeast China

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Shunlin, E-mail: tangshunlin@vip.gyig.ac.cn [Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan province (China); State Key laboratory of Geochemistry, Chinese Academy of Science, Guiyang (China); Huang, Zhongwei; Liu, Jun; Yang, Zaichan [Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan province (China); Lin, Qinhua [State Key laboratory of Geochemistry, Chinese Academy of Science, Guiyang (China)

    2012-10-15

    The historical mercury accumulation rates (Hg AR) resulting from atmospheric deposition to Xiaoxing'an Mountain were determined via analysis of {sup 210}Pb- and {sup 14}C-dated cores up to 5000 years old. Natural Hg AR background, pre-industrial Hg AR and maximum industrial Hg AR in Northeast China were 2.2 {+-}1.0 {mu}g/m{sup 2}/yr for 5100-4500 BP, 5.7 {mu}g/m{sup 2}/yr and 112.4 {mu}g/m{sup 2}/yr, respectively. We assumed that the increase in Hg deposition in the Xiaoxing'an mountain area during industrial time was mainly attributed to local anthropogenic emissions around this peat bog.

  16. Enhanced solubility and ecological impact of atmospheric phosphorus deposition upon extended seawater exposure.

    Science.gov (United States)

    Mackey, Katherine R M; Roberts, Kathryn; Lomas, Michael W; Saito, Mak A; Post, Anton F; Paytan, Adina

    2012-10-01

    Atmospheric P solubility affects the amount of P available for phytoplankton in the surface ocean, yet our understanding of the timing and extent of atmospheric P solubility is based on short-term leaching experiments where conditions may differ substantially from the surface ocean. We conducted longer- term dissolution experiments of atmospheric aerosols in filtered seawater, and found up to 9-fold greater dissolution of P after 72 h compared to instantaneous leaching. Samples rich in anthropogenic materials released dissolved inorganic P (DIP) faster than mineral dust. To gauge the effect of biota on the fate of atmospheric P, we conducted field incubations with aerosol samples collected in the Sargasso Sea and Red Sea. In the Sargasso Sea phytoplankton were not P limited, and biological activity enhanced DIP release from aerosols, and aerosols induced biological mineralization of dissolved organic P in seawater, leading to DIP accumulation. However, in the Red Sea where phytoplankton were colimited by P and N, soluble P was rapidly consumed by phytoplankton following aerosol enrichment. Our results suggest that atmospheric P dissolution could continue over multiple days once reaching the surface ocean, and that previous estimates of atmospheric P deposition may underestimate the contribution from this source.

  17. An evaluation of atmospheric Nr pollution and deposition in North China after the Beijing Olympics

    Science.gov (United States)

    Luo, X. S.; Liu, P.; Tang, A. H.; Liu, J. Y.; Zong, X. Y.; Zhang, Q.; Kou, C. L.; Zhang, L. J.; Fowler, D.; Fangmeier, A.; Christie, P.; Zhang, F. S.; Liu, X. J.

    2013-08-01

    North China is known for its large population densities and rapid development of industry and agriculture. Air quality around Beijing improved substantially during the 2008 Summer Olympics. We measured atmospheric concentrations of various Nr compounds at three urban sites and three rural sites in North China from 2010 to 2012 and estimated N dry and wet deposition by inferential models and the rain gauge method to determine current air conditions with respect to reactive nitrogen (Nr) compounds and nitrogen (N) deposition in Beijing and the surrounding area. NH3, NO2, and HNO3 and particulate NH4+ and NO3-, and NH4+-N and NO3--N in precipitation averaged 8.2, 11.5, 1.6, 8.2 and 4.6 μg N m-3, and 2.9 and 1.9 mg N L-1, respectively, with large seasonal and spatial variability. Atmospheric Nr (especially oxidized N) concentrations were highest at urban sites. Dry deposition of Nr ranged from 35.2 to 60.0 kg N ha-1 yr-1, with wet deposition of Nr of 16.3 to 43.2 kg N ha-1 yr-1 and total deposition of 54.4-103.2 kg N ha-1 yr-1. The rates of Nr dry and wet deposition were 36.4 and 33.2% higher, respectively, at the urban sites than at the rural sites. These high levels reflect the occurrence of a wide range of Nr pollution in North China and suggest that further strict air pollution control measures are required.

  18. Challenges in tracing the fate and effects of atmospheric polycyclic aromatic hydrocarbon deposition in vascular plants.

    Science.gov (United States)

    Desalme, Dorine; Binet, Philippe; Chiapusio, Geneviève

    2013-05-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic pollutants that raise environmental concerns because of their toxicity. Their accumulation in vascular plants conditions harmful consequences to human health because of their position in the food chain. Consequently, understanding how atmospheric PAHs are taken up in plant tissues is crucial for risk assessment. In this review we synthesize current knowledge about PAH atmospheric deposition, accumulation in both gymnosperms and angiosperms, mechanisms of transfer, and ecological and physiological effects. PAHs emitted in the atmosphere partition between gas and particulate phases and undergo atmospheric deposition on shoots and soil. Most PAH concentration data from vascular plant leaves suggest that contamination occurs by both direct (air-leaf) and indirect (air-soil-root) pathways. Experimental studies demonstrate that PAHs affect plant growth, interfering with plant carbon allocation and root symbioses. Photosynthesis remains the most studied physiological process affected by PAHs. Among scientific challenges, identifying specific physiological transfer mechanisms and improving the understanding of plant-symbiont interactions in relation to PAH pollution remain pivotal for both fundamental and applied environmental sciences.

  19. Development of ion-exchange collectors for monitoring atmospheric deposition of inorganic pollutants in Alaska parklands

    Science.gov (United States)

    Brumbaugh, William G.; Arms, Jesse W.; Linder, Greg L.; Melton, Vanessa D.

    2016-09-19

    Between 2010 and 2014, the U.S. Geological Survey completed a series of laboratory and field experiments designed to develop methodology to support the National Park Service’s long-term atmospheric pollutant monitoring efforts in parklands of Arctic Alaska. The goals of this research were to develop passive sampling methods that could be used for long-term monitoring of inorganic pollutants in remote areas of arctic parklands and characterize relations between wet and dry deposition of atmospheric pollutants to that of concentrations accumulated by mosses, specifically the stair-step, splendid feather moss, Hylocomium splendens. Mosses and lichens have been used by National Park Service managers as atmospheric pollutant biomonitors since about 1990; however, additional research is needed to better characterize the dynamics of moss bioaccumulation for various classes of atmospheric pollutants. To meet these research goals, the U.S. Geological Survey investigated the use of passive ionexchange collectors (IECs) that were adapted from the design of Fenn and others (2004). Using a modified IEC configuration, mulitple experiments were completed that included the following: (a) preliminary laboratory and development testing of IECs, (b) pilot-scale validation field studies during 2012 with IECs at sites with instrumental monitoring stations, and (c) deployment of IECs in 2014 at sites in Alaska having known or suspected regional sources of atmospheric pollutants where samples of Hylocomium splendens moss also could be collected for comparison. The targeted substances primarily included ammonium, nitrate, and sulfate ions, and certain toxicologically important trace metals, including cadmium, cobalt, copper, nickel, lead, and zinc.Deposition of atmospheric pollutants is comparatively low throughout most of Alaska; consequently, modifications of the original IEC design were needed. The most notable modification was conversion from a single-stage mixed-bed column to a two

  20. Assessment of atmospheric heavy metal deposition in the Tarkwa gold mining area of Ghana using epiphytic lichens

    Energy Technology Data Exchange (ETDEWEB)

    Boamponsem, L.K. [Department of Theoretical and Applied Biology, College of Science, Kwame Nkrumah University of Science and Technology, University Post Office, Kumasi (Ghana); Department of Laboratory Technology, School of Physical Sciences, University of Cape Coast, Cape Coast (Ghana); Adam, J.I. [Department of Theoretical and Applied Biology, College of Science, Kwame Nkrumah University of Science and Technology, University Post Office, Kumasi (Ghana); Dampare, S.B., E-mail: dampare@cc.okayama-u.ac.j [National Nuclear Research Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon-Accra (Ghana); Department of Earth Sciences, Okayama University, 1-1, Tsushima-Naka 3-Chome, Okayama 700-8530 (Japan); Nyarko, B.J.B. [National Nuclear Research Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon-Accra (Ghana); Essumang, D.K. [Department of Laboratory Technology, School of Physical Sciences, University of Cape Coast, Cape Coast (Ghana)

    2010-05-01

    In situ lichens (Parmelia sulcata) have been used to assess atmospheric heavy metal deposition in the Tarkwa gold mining area of Ghana. Total heavy metal concentrations obtained by instrumental neutron activation analysis (INAA) were processed by positive matrix factorization (PMF), principal component (PCA) and cluster (CA) analyses. The pollution index factor (PIF) and pollution load index (PLI) criteria revealed elevated levels of Sb, Mn, Cu, V, Al, Co, Hg, Cd and As in excess of the background values. The PCA and CA classified the examined elements into anthropogenic and natural sources, and PMF resolved three primary sources/factors: agricultural activities and other non-point anthropogenic origins, natural soil dust, and gold mining activities. Gold mining activities, which are characterized by dominant species of Sb, Th, As, Hg, Cd and Co, and significant contributions of Cu, Al, Mn and V, are the main contributors of heavy metals in the atmosphere of the study area.

  1. Exploratory analysis of atmospheric pollution in a coastal forest ecosystem in central Italy

    OpenAIRE

    Rita Aromolo; Valerio Moretti; Luca Salvati

    2015-01-01

    Exploratory analysis of atmospheric pollution in a coastal forest ecosystem in central Italy - The study of spatial and temporal distribution of heavy metals in the atmosphere through the continuous assessment of deposition is of great interest for the analysis of anthropogenic pressure on the environment and the potential toxicity to humans and other living organisms. Information based on reliable estimates of heavy metals is therefore crucial for the evaluation of environmental quality. Tre...

  2. Atmospheric mercury deposition and its contribution of the regional atmospheric transport to mercury pollution at a national forest nature reserve, southwest China.

    Science.gov (United States)

    Ma, Ming; Wang, Dingyong; Du, Hongxia; Sun, Tao; Zhao, Zheng; Wei, Shiqing

    2015-12-01

    Atmospheric mercury deposition by wet and dry processes contributes to the transformation of mercury from atmosphere to terrestrial and aquatic systems. Factors influencing the amount of mercury deposited to subtropical forests were identified in this study. Throughfall and open field precipitation samples were collected in 2012 and 2013 using precipitation collectors from forest sites located across Mt. Jinyun in southwest China. Samples were collected approximately every 2 weeks and analyzed for total (THg) and methyl mercury (MeHg). Forest canopy was the primary factor on THg and MeHg deposition. Simultaneously, continuous measurements of atmospheric gaseous elemental mercury (GEM) were carried out from March 2012 to February 2013 at the summit of Mt. Jinyun. Atmospheric GEM concentrations averaged 3.8 ± 1.5 ng m(-3), which was elevated compared with global background values. Sources identification indicated that both regional industrial emissions and long-range transport of Hg from central, northeast, and southwest China were corresponded to the elevated GEM levels. Precipitation deposition fluxes of THg and MeHg in Mt. Jinyun were slightly higher than those reported in Europe and North America, whereas total fluxes of MeHg and THg under forest canopy on Mt. Jiuyun were 3 and 2.9 times of the fluxes of THg in wet deposition in the open. Highly elevated litterfall deposition fluxes suggest that even in remote forest areas of China, deposition of atmospheric Hg(0) via uptake by vegetation leaf may be a major pathway for the deposition of atmospheric Hg. The result illustrates that areas with greater atmospheric pollution can be expected to have greater fluxes of Hg to soils via throughfall and litterfall.

  3. External quality-assurance project report for the National Atmospheric Deposition Program/National Trends Network and Mercury Deposition Network, 2009-2010

    Science.gov (United States)

    Wetherbee, Gregory A.; Martin, RoseAnn; Rhodes, Mark F.; Chesney, Tanya A.

    2014-01-01

    The U.S. Geological Survey operated six distinct programs to provide external quality-assurance monitoring for the National Atmospheric Deposition Program/National Trends Network (NTN) and Mercury Deposition Network (MDN) during 2009–2010. The field-audit program assessed the effects of onsite exposure, sample handling, and shipping on the chemistry of NTN samples; a system-blank program assessed the same effects for MDN. Two interlaboratory-comparison programs assessed the bias and variability of the chemical analysis data from the Central Analytical Laboratory (CAL) and Mercury (Hg) Analytical Laboratory (HAL). The blind-audit program was also implemented for the MDN to evaluate analytical bias in total Hg concentration data produced by the HAL. The co-located-sampler program was used to identify and quantify potential shifts in NADP data resulting from replacement of original network instrumentation with new electronic recording rain gages (E-gages) and precipitation collectors that use optical sensors. The results indicate that NADP data continue to be of sufficient quality for the analysis of spatial distributions and time trends of chemical constituents in wet deposition across the United States. Results also suggest that retrofit of the NADP networks with the new precipitation collectors could cause –8 to +14 percent shifts in NADP annual precipitation-weighted mean concentrations and total deposition values for ammonium, nitrate, sulfate, and hydrogen ion, and larger shifts (+13 to +74 percent) for calcium, magnesium, sodium, potassium, and chloride. The prototype N-CON Systems bucket collector is more efficient in the catch of precipitation in winter than Aerochem Metrics Model 301 collector, especially for light snowfall.

  4. [Characteristics of Atmospheric Dry and Wet Deposition of Trace Metals in the Hinterland of the Three Gorges Reservoir, China].

    Science.gov (United States)

    Zhang, Liu-yi; Liu, Yuan; Qiao, Bao-qing; Fu, Chuan; Wang, Huan-bo; Huang, Yi-min; Yang, Fu-mo

    2016-02-15

    In order to investigate the characteristics of atmospheric trace metals deposition in the hinterland of the Three Gorges Reservoir, the wet and dry deposition samples were collected at an urban area sampling site in Wanzhou during January to June 2014. Besides, the samples were collected at five other sampling sites in April 2014 for comparative analysis, including factory region, town suburb, nature reserve, county suburb, and rural area. pH, conductivity, and trace metals (Al, As, B, Ba, Bi, Cd, Co, Cr, Cu, Fe, Li, Mn, Pb, Ni, Sb, Sr, Sn, Ti, Zn, V) were analyzed. In urban area, the acid rain frequency was 48.44% , and the acid rain occurred mainly in the period of January to April. The order of acid rain frequency in various functional areas was factory region > urban area > county suburb > town suburb > nature reserve > county rural area. All of the trace metals in wet deposition during the sampling period were lower than the National Environmental Quality Standard for Surface Water Standard of Class III. Cd, Cu, Ph and Zn were found exceeding the standard of class I , and the pollution in factory region was more serious compared to other functional areas. The extract pH of dry deposition in urban area was in the range of 4.91-6.74, with an average value of 5.79. The order of dry deposition in various functional areas was factory region > county suburb > urban area > county rural area > town suburb > nature reserve, which was exactly the same as that of the wet deposition, indicating the similar sources of dry and wet deposition. In urban area, the contents of Ba, Co, Cu, Cr, Li, Mn, Ni, Sr, Zn in dry deposition were greater than those in wet deposition, but the contents of Al, As, B, Bi, Cd, Fe, Ph, Sb, Sn, Ti, V showed the opposite trend. Analysis of the enrichment factors showed that Al was in moderate enrichment, while Bi and Cd were significantly enriched. PMID:27363132

  5. Multi-year Surface Deposition of {sup 210}Pb and {sup 210}Po at Lisbon - Atmospheric Depositions of {sup 210}Pb and {sup 210}Po in Lisbon, Portugal

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Fernando P.; Oliveira, Joao M.; Alberto, G. [Instituto Superior Tecnico/ Campus Tecnologico e Nuclear, Universidade Tecnica de Lisboa, E.N. 10, 2686-953 Sacavem (Portugal)

    2014-07-01

    The long lived radon daughters {sup 210}Pb and {sup 210}Po were determined in samples of total atmospheric depositions obtained with surface collectors continuously operated during 5 years, near Lisbon. The average annual {sup 210}Pb flux was 66±12 Bq m{sup -2}, and the average annual {sup 210}Po flux was 8±3 Bq m{sup -2}, with an overall {sup 210}Po/{sup 210}Pb activity ratio of 0.15±0.06. Direct determination of the {sup 210}Pb atmospheric flux was compared with the {sup 210}Pb excess determined in soil surface layers along with atmospheric depositions of {sup 137}Cs. The deposition of atmospheric {sup 210}Pb was positively correlated with seasonal rainfall, while {sup 210}Po was mainly originated in soil particles re-suspension throughout the year and also in seasonal forest fires. Unusually high {sup 210}Po/{sup 210}Pb activity ratios, higher than unity, were occasionally recorded in atmospheric depositions and the sources and causes are discussed. Long time-series of {sup 210}Pb and {sup 210}Po deposition fluxes, as presented herein are useful to test and constrain parameters of the atmospheric Global Circulation Models. (authors)

  6. Multi-year Surface Deposition of 210Pb and 210Po at Lisbon - Atmospheric Depositions of 210Pb and 210Po in Lisbon, Portugal

    International Nuclear Information System (INIS)

    The long lived radon daughters 210Pb and 210Po were determined in samples of total atmospheric depositions obtained with surface collectors continuously operated during 5 years, near Lisbon. The average annual 210Pb flux was 66±12 Bq m-2, and the average annual 210Po flux was 8±3 Bq m-2, with an overall 210Po/210Pb activity ratio of 0.15±0.06. Direct determination of the 210Pb atmospheric flux was compared with the 210Pb excess determined in soil surface layers along with atmospheric depositions of 137Cs. The deposition of atmospheric 210Pb was positively correlated with seasonal rainfall, while 210Po was mainly originated in soil particles re-suspension throughout the year and also in seasonal forest fires. Unusually high 210Po/210Pb activity ratios, higher than unity, were occasionally recorded in atmospheric depositions and the sources and causes are discussed. Long time-series of 210Pb and 210Po deposition fluxes, as presented herein are useful to test and constrain parameters of the atmospheric Global Circulation Models. (authors)

  7. A new sampler for collecting separate dry and wet atmospheric depositions of trace organic chemicals

    Science.gov (United States)

    Waite, Don T.; Cessna, Allan J.; Gurprasad, Narine P.; Banner, James

    Studies conducted in Saskatchewan and elsewhere have demonstrated the atmospheric transport of agricultural pesticides and other organic contaminants and their deposition into aquatic ecosystems. To date these studies have focused on ambient concentrations in the atmosphere and in wet precipitation. To measure the dry deposition of organic chemicals, a new sampler was designed which uses a moving sheet of water to passively trap dry particles and gasses. The moving sheet of water drains into a reservoir and, during recirculation through the sampler, is passed through an XAD-2 resin column which adsorbs the trapped organic contaminants. All surfaces which contact the process water are stainless steel or Teflon. Chemicals collected can be related to airborne materials depositing into aquatic ecosystems. The sampler has received a United States patent (number 5,413,003 - 9 May 1996) with the Canadian patent pending. XAD-2 resin adsorption efficiencies for 10 or 50 μg fortifications of ten pesticides ranged from 76% for atrazine (2-chloro-4-ethylamino-6-isopropylamino- S-triazine) to 110% for triallate [ S-(2,3,3-trichloro-2-phenyl)bis(1-methylethyl)carbamothioate], dicamba (2-methoxy-3,6-dichlorobenzoic acid) and toxaphene (chlorinated camphene mixture). Field testing using duplicate samplers showed good reproducibility and amounts trapped were consistent with those from high volume and bulk pan samplers located on the same site. Average atmospheric dry deposition rates of three chemicals, collected for 5 weeks in May and June, were: dicamba, 69 ng m -2 da -1; 2,4-D (2,4-dichlorophenoxyacetic acid), 276 ng m -2 da -1: and, γ-HCH ( γ-1, 2, 3, 4, 5, 6-hexachlorocyclohexane), 327 ng m -2 da -1.

  8. Critical loads of nitrogen deposition and critical levels of atmospheric ammonia for mediterranean evergreen woodlands

    Science.gov (United States)

    Pinho, P.; Theobald, M. R.; Dias, T.; Tang, Y. S.; Cruz, C.; Martins-Loução, M. A.; Máguas, C.; Sutton, M.; Branquinho, C.

    2011-11-01

    Nitrogen (N) has emerged in recent years as a key factor associated with global changes, with impacts on biodiversity, ecosystems functioning and human health. In order to ameliorate the effects of excessive N, safety thresholds have been established, such as critical loads (deposition fluxes) and levels (concentrations). For Mediterranean ecosystems, few studies have been carried out to assess these parameters. Our objective was therefore to determine the critical loads of N deposition and long-term critical levels of atmospheric ammonia for Mediterranean evergreen woodlands. For that we have considered changes in epiphytic lichen communities, which have been shown to be one of the most sensitive to excessive N. Based on a classification of lichen species according to their tolerance to N we grouped species into response functional groups, which we used as a tool to determine the critical loads and levels. This was done under Mediterranean climate, in evergreen cork-oak woodlands, by sampling lichen functional diversity and annual atmospheric ammonia concentrations and modelling N deposition downwind from a reduced N source (a cattle barn). By modelling the highly significant relationship between lichen functional groups and N deposition, the critical load was estimated to be below 26 kg (N) ha-1 yr-1, which is within the upper range established for other semi-natural ecosystems. By modelling the highly significant relationship of lichen functional groups with annual atmospheric ammonia concentration, the critical level was estimated to be below 1.9 μg m-3, in agreement with recent studies for other ecosystems. Taking into account the high sensitivity of lichen communities to excessive N, these values should be taken into account in policies that aim at protecting Mediterranean woodlands from the initial effects of excessive N.

  9. Critical loads of nitrogen deposition and critical levels of atmospheric ammonia for mediterranean evergreen woodlands

    Directory of Open Access Journals (Sweden)

    P. Pinho

    2011-11-01

    Full Text Available Nitrogen (N has emerged in recent years as a key factor associated with global changes, with impacts on biodiversity, ecosystems functioning and human health. In order to ameliorate the effects of excessive N, safety thresholds have been established, such as critical loads (deposition fluxes and levels (concentrations. For Mediterranean ecosystems, few studies have been carried out to assess these parameters. Our objective was therefore to determine the critical loads of N deposition and long-term critical levels of atmospheric ammonia for Mediterranean evergreen woodlands. For that we have considered changes in epiphytic lichen communities, which have been shown to be one of the most sensitive to excessive N. Based on a classification of lichen species according to their tolerance to N we grouped species into response functional groups, which we used as a tool to determine the critical loads and levels. This was done under Mediterranean climate, in evergreen cork-oak woodlands, by sampling lichen functional diversity and annual atmospheric ammonia concentrations and modelling N deposition downwind from a reduced N source (a cattle barn. By modelling the highly significant relationship between lichen functional groups and N deposition, the critical load was estimated to be below 26 kg (N ha−1 yr−1, which is within the upper range established for other semi-natural ecosystems. By modelling the highly significant relationship of lichen functional groups with annual atmospheric ammonia concentration, the critical level was estimated to be below 1.9 μg m−3, in agreement with recent studies for other ecosystems. Taking into account the high sensitivity of lichen communities to excessive N, these values should be taken into account in policies that aim at protecting Mediterranean woodlands from the initial effects of excessive N.

  10. Control of Toxic Chemicals in Puget Sound, Phase 3: Study of Atmospheric Deposition of Air Toxics to the Surface of Puget Sound

    Energy Technology Data Exchange (ETDEWEB)

    Brandenberger, Jill M.; Louchouarn, Patrick; Kuo, Li-Jung; Crecelius, Eric A.; Cullinan, Valerie I.; Gill, Gary A.; Garland, Charity R.; Williamson, J. B.; Dhammapala, R.

    2010-07-05

    The results of the Phase 1 Toxics Loading study suggested that runoff from the land surface and atmospheric deposition directly to marine waters have resulted in considerable loads of contaminants to Puget Sound (Hart Crowser et al. 2007). The limited data available for atmospheric deposition fluxes throughout Puget Sound was recognized as a significant data gap. Therefore, this study provided more recent or first reported atmospheric deposition fluxes of PAHs, PBDEs, and select trace elements for Puget Sound. Samples representing bulk atmospheric deposition were collected during 2008 and 2009 at seven stations around Puget Sound spanning from Padilla Bay south to Nisqually River including Hood Canal and the Straits of Juan de Fuca. Revised annual loading estimates for atmospheric deposition to the waters of Puget Sound were calculated for each of the toxics and demonstrated an overall decrease in the atmospheric loading estimates except for polybrominated diphenyl ethers (PBDEs) and total mercury (THg). The median atmospheric deposition flux of total PBDE (7.0 ng/m2/d) was higher than that of the Hart Crowser (2007) Phase 1 estimate (2.0 ng/m2/d). The THg was not significantly different from the original estimates. The median atmospheric deposition flux for pyrogenic PAHs (34.2 ng/m2/d; without TCB) shows a relatively narrow range across all stations (interquartile range: 21.2- 61.1 ng/m2/d) and shows no influence of season. The highest median fluxes for all parameters were measured at the industrial location in Tacoma and the lowest were recorded at the rural sites in Hood Canal and Sequim Bay. Finally, a semi-quantitative apportionment study permitted a first-order characterization of source inputs to the atmosphere of the Puget Sound. Both biomarker ratios and a principal component analysis confirmed regional data from the Puget Sound and Straits of Georgia region and pointed to the predominance of biomass and fossil fuel (mostly liquid petroleum products such

  11. Increased atmospheric deposition of mercury in reference lakes near major urban areas

    Science.gov (United States)

    Van Metre, P.C.

    2012-01-01

    Atmospheric deposition of Hg is the predominant pathway for Hg to reach sensitive ecosystems, but the importance of emissions on near-field deposition remains unclear. To better understand spatial variability in Hg deposition, mercury concentrations were analyzed in sediment cores from 12 lakes with undeveloped watersheds near to (150 km) several major urban areas in the United States. Background and focusing corrected Hg fluxes and flux ratios (modern to background) in the near-urban lakes (68 ?? 6.9 ??g m -2 yr -1 and 9.8 ?? 4.8, respectively) greatly exceed those in the remote lakes (14 ?? 9.3 ??g m -2 yr -1 and 3.5 ?? 1.0) and the fluxes are strongly related to distance from the nearest major urban area (r 2 = 0.87) and to population and Hg emissions within 50-100 km of the lakes. Comparison to monitored wet deposition suggests that dry deposition is a major contributor of Hg to lakes near major urban areas. ?? 2011 Elsevier Ltd. All rights reserved.

  12. Four studies on effects of environmental factors on the quality of National Atmospheric Deposition Program measurements

    Science.gov (United States)

    Wetherbee, Gregory A.; Latysh, Natalie E.; Lehmann, Christopher M.B.; Rhodes, Mark F.

    2011-01-01

    Selected aspects of National Atmospheric Deposition Program / National Trends Network (NADP/NTN) protocols are evaluated in four studies. Meteorological conditions have minor impacts on the error in NADP/NTN sampling. Efficiency of frozen precipitation sample collection is lower than for liquid precipitation samples. Variability of NTN measurements is higher for relatively low-intensity deposition of frozen precipitation than for higher-intensity deposition of liquid precipitation. Urbanization of the landscape surrounding NADP/NTN sites is not affecting trends in wet-deposition chemistry data to a measureable degree. Five NADP siting criteria intended to preserve wet-deposition sample integrity have varying degrees of effectiveness. NADP siting criteria for objects within the 90 degrees cones and trees within the 120 degrees cones projected from the collector bucket to sky are important for protecting sample integrity. Tall vegetation, fences, and other objects located within 5 meters of the collectors are related to the frequency of visible sample contamination, indicating the importance of these factors in NADP siting criteria.

  13. Deposition of hard thin films from HMDSO in atmospheric pressure dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Trunec, D; Zajickova, L; BursIkova, V; Studnicka, F; Stahel, P; Prysiazhnyi, V; Navratil, Z; Franta, D [Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Perina, V [Institute of Nuclear Physics, Academy of Sciences of the Czech Republic, 250 68 Rez (Czech Republic); Houdkova, J, E-mail: trunec@physics.muni.c [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 53 Prague (Czech Republic)

    2010-06-09

    An atmospheric pressure dielectric barrier discharge burning in nitrogen with a small admixture of hexamethyldisiloxane (HMDSO) was used for the deposition of thin organosilicon films. The thin films were deposited on glass, silicon and polycarbonate substrates, and the substrate temperature during the deposition process was increased up to values within the range 25-150 {sup 0}C in order to obtain hard SiO{sub x}-like thin films. The properties of the discharge were studied by means of optical emission spectroscopy and electrical measurements. The deposited films were characterized by the Rutherford backscattering and elastic recoil detection methods, x-ray photoelectron spectroscopy, infrared spectroscopy measurements, ellipsometry and the depth sensing indentation technique. It was found that the films' properties depend significantly on the substrate temperature at deposition. An increase in substrate temperature from 25 to 150 {sup 0}C led to an increase in film hardness from 0.4 to 7 GPa and the film chemical composition changed from CH{sub x}Si{sub y}O{sub z} to SiO{sub x}H{sub y}. The films were transparent in the visible range.

  14. Modelling atmospheric dry deposition in urban areas using an urban canopy approach

    Directory of Open Access Journals (Sweden)

    N. Cherin

    2015-03-01

    Full Text Available Atmospheric dry deposition is typically modelled using an average roughness length, which depends on land use. This classical roughness-length approach cannot account for the spatial variability of dry deposition in complex settings such as urban areas. Urban canopy models have been developed to parametrise momentum and heat transfer. We extend this approach here to mass transfer, and a new dry deposition model based on the urban canyon concept is presented. It uses a local mixing-length parametrisation of turbulence within the canopy, and a description of the urban canopy via key parameters to provide spatially distributed dry deposition fluxes. Three different flow regimes are distinguished in the urban canyon depending on the height-to-width ratio of built areas: isolated roughness flow, wake interference flow and skimming flow. Differences between the classical roughness-length model and the model developed here are investigated. Sensitivity to key parameters are discussed. This approach provides spatially distributed dry deposition fluxes that depend on surfaces (streets, walls, roofs and flow regimes (recirculation and ventilation within the urban area.

  15. Modelling atmospheric dry deposition in urban areas using an urban canopy approach

    Directory of Open Access Journals (Sweden)

    N. Cherin

    2014-12-01

    Full Text Available Atmospheric dry deposition is typically modelled using an average roughness length, which depends on land use. This classical roughness-length approach cannot account for the spatial variability of dry deposition in complex settings such as urban areas. Urban canopy models have been developed to parametrise momentum and heat transfer. We extend this approach here to mass transfer and a new dry deposition model based on the urban canyon concept is presented. It uses a local mixing length parametrisation of turbulence within the canopy, and a description of the urban canopy via key parameters to provide spatially-distributed dry deposition fluxes. Three different flow regimes are distinguished in the urban canyon depending on the height-to-width ratio of built areas: isolated roughness flow, wake interference flow and skimming flow. Differences between the classical roughness-length model and the model developed here are investigated. Sensitivity to key parameters are discussed. This approach provides spatially-distributed dry deposition fluxes that depend on surfaces (streets, walls, roofs and flow regimes (recirculation and ventilation within the urban area.

  16. Box-modeling of the impacts of atmospheric nitrogen deposition and benthic remineralization on the nitrogen cycle of the eastern tropical South Pacific

    Directory of Open Access Journals (Sweden)

    B. Su

    2015-09-01

    Full Text Available Both atmospheric deposition and benthic remineralization influence the marine nitrogen cycle, and hence ultimately also marine primary production. The biological and biogeochemical relations of the eastern tropical South Pacific (ETSP to nitrogen deposition, benthic denitrification and phosphate regeneration are analysed in a prognostic box model of the oxygen, nitrogen and phosphorus cycles in the ETSP. In the model, atmospheric nitrogen deposition based on estimates for the years 2000–2009 is offset by half by reduced N2 fixation, with the other half transported out of the model domain. Both model- and data-based benthic denitrification are found to trigger nitrogen fixation, partly compensating for the NO3− loss. Since phosphate is the ultimate limiting nutrient in the model, enhanced sedimentary phosphate regeneration under suboxic conditions stimulates primary production and subsequent export production and NO3− loss in the oxygen minimum zone (OMZ. A sensitivity analysis of the local response to both atmospheric deposition and benthic remineralization indicates dominant stabilizing feedbacks in the ETSP, which tend to keep a balanced nitrogen inventory, i.e., nitrogen input by atmospheric deposition is counteracted by decreasing nitrogen fixation; NO3− loss via benthic denitrification is partly compensated by increased nitrogen fixation; enhanced nitrogen fixation stimulated by phosphate regeneration is partly removed by the stronger water-column denitrification. Even though the water column in our model domain acts as a NO3− source, the ETSP including benthic denitrification might become a NO3− sink.

  17. Atmospheric transport, deposition, and fate of triazine herbicides and their metabolites in pristine areas at Isle Royale National Park

    Science.gov (United States)

    Thurman, E.M.; Cromwell, A.E.

    2000-01-01

    Trace concentrations of triazine herbicides, used in the Midwestern United States, are being transported atmospherically hundreds of kilometers and deposited by precipitation onto pristine areas, such as Isle Royale National Park (Lake Superior). Atrazine, deethylatrazine, deisopropylatrazine, and cyanazine were detected in Isle Royale rainfall from mid-May to early July (1992-1994) at concentrations of less than 0.005 to 1.8 ??g/L. Analysis of predominant wind direction indicated that the herbicides originated from the upper Midwestern United States. The annual mass of herbicides deposited by rainfall varied between years, from 13.4 ??g/m2/yr for 1992, 3.7 ??g/m2/yr for 1993, and 54 ??g/m2/yr for 1994. Atrazine and deethylatrazine were found also in concentrations of less than 5-22 ng/L in lakes across Isle Royale. Concentrations of atrazine in the surface layer of the lakes increased during deposition periods and decreased later in the year. The fate of triazines in shallow lakes suggests faster degradation and shorter half-lives, while deeper lakes have residence times for atrazine that may exceed 10 years.Trace concentrations of triazine herbicides, used in the Midwestern United States, are being transported atmospherically hundreds of kilometers and deposited by precipitation onto pristine areas, such as Isle Royale National Park (Lake Superior). Atrazine, deethylatrazine, deisopropylatrazine, and cyanazine were detected in Isle Royale rainfall from mid-May to early July (1992-1994) at concentrations of less than 0.005 to 1.8 ??g/L. Analysis of predominant wind direction indicated that the herbicides originated from the upper Midwestern United States. The annual mass of herbicides deposited by rainfall varied between years, from 13.4 ??g/m2/yr for 1992, 3.7 ??g/m2/yr for 1993, and 54 ??g/m2/yr for 1994. Atrazine and deethylatrazine were found also in concentrations of less than 5-22 ng/L in lakes across Isle Royale. Concentrations of atrazine in the surface

  18. Heavy metals in particulate and colloidal matter from atmospheric deposition of urban Guangzhou, South China.

    Science.gov (United States)

    Huang, Wen; Duan, Dandan; Zhang, Yulong; Cheng, Hefa; Ran, Yong

    2014-08-30

    Suspended particulate matter (SPM) and colloidal matter (COM) in annual dry and wet deposition samples in urban Guangzhou were for the first time collected, and their trace metals were investigated by using inductively coupled plasma mass spectrometry (ICP-MS). The deposition flux of SPM and of metal elements varied largely among the investigated seasons, and reached the maximum in spring. The correlation analysis indicated that significant correlations existed among some of the metal elements in the deposition samples. The enrichment factors (EF) of metals in COM in the deposition ranging from 79.66 to 130,000 were much higher than those of SPM ranging from 1.65 to 286.48, indicating the important role of COM. The factor analysis showed that emissions from street dust, non-ferrous metal production, and heavy fuel oil were major sources of the trace metals. Positive matrix factorization (PMF) model was used to quantitatively estimate anthropogenic source.

  19. Do N-isotopes in atmospheric nitrate deposition reflect air pollution levels?

    Science.gov (United States)

    Beyn, Fabian; Matthias, Volker; Aulinger, Armin; Dähnke, Kirstin

    2015-04-01

    Dry and wet deposition of atmospheric reactive nitrogen compounds mostly originate from anthropogenic NH3 and NOX sources. Regarding land-borne pollutants, coastal environments usually have a lower pollution level than terrestrial/urban areas, which have a greater anthropogenic imprint. To investigate this spatial characteristic, we measured NO3- and NH4+ deposition and N isotopes of NO3-(δ15N-NO3-) in 94 and 88 wet and dry deposition samples, respectively, at a coastal (List on Sylt) and a terrestrial/urban site (Geesthacht) in Germany from May 2012 to May 2013. A higher total N deposition rate was observed in Geesthacht (10.4 vs. 8.9 kg N ha-1 yr-1) due to higher NH4+ deposition, which can be explained by more agricultural influence. Surprisingly, overall NO3- fluxes were higher at the coastal site than at the terrestrial/urban site. We assume that sea-salt aerosols and the increased influence of NOX emissions from ships in most recent times compensate the higher terrestrial/urban pollution level and thus lead to higher NO3- fluxes in dry and comparable fluxes in wet deposition at the coastal site, despite a much lower impact of land-based sources. In line with this, overall mean N isotopes values of NO3- show higher values in List than in Geesthacht in dry (+3.1 vs. +1.9‰) as well as in wet deposition (-0.1 vs. -1.0‰). This surprising result can mainly be attributed to an emerging source of NOX, ship emissions, which have a distinctly higher impact at the coastal site. The usage of heavy oil and possibly new technologies in marine engines, which emit more enriched 15N in comparison to older engines, caused the spatial isotopic differences.

  20. Atmospheric Nitrogen Deposition Threatens Biodiversity: Development of Novel Mitigation Policies in California

    Science.gov (United States)

    Weiss, S. B.

    2011-12-01

    Atmospheric nitrogen deposition threatens biodiversity in many parts of the world. In California, 20% of the land surface receives > 5 kg-N ha-1 year-1, with hotspots receiving > 50 kg-N ha-1 year-1. Documented impacts of N-deposition include increased growth of annual grass and other invasives in coastal sage scrub, serpentine grasslands, vernal pools, and deserts, altered nutrient cycling and fuel accumulation of montane forests, enhanced fire cycles, nitrate leaching into surface and groundwater, and eutrophication of montane lakes such as Lake Tahoe. 40% of listed threatened and endangered plants are exposed to > 5 kg-N ha-1 year-1, and N-deposition is arguably a greater immediate threat to biodiversity than is climate change. Appropriate policy responses are lagging, because the magnitude of N-deposition impacts on biodiversity is poorly known in the broader conservation/regulatory community and the general public. Policies to decrease emissions and deposition are clearly the ultimate solution on a decadal time scale. In the interim, habitat management is critical to preventing extinction of many species. This presentation reviews recent policies and regulatory actions in California that address N-deposition impacts on biodiversity. The immediate and long-term needs for invasive weed management are overwhelming and require long-term endowment funding. Mitigation requirements under the US Endangered Species Act have been used to secure land and management resources. The on-going story of the threatened Bay checkerspot butterfly, from the first precedent setting mitigation in 2001 through a regional Habitat Conservation Plan (HCP), illustrates the development of these novel policies based on science, regulatory authority, grassroots activism, public education, habitat restoration, and legal actions. The 50-year HCP will ultimately result in a network of conserved lands with management endowments. Eventually N-deposition may be reduced below critical loads

  1. Pitfalls and new mechanisms in moss isotope biomonitoring of atmospheric nitrogen deposition.

    Science.gov (United States)

    Liu, Xue-Yan; Koba, Keisuke; Liu, Cong-Qiang; Li, Xiao-Dong; Yoh, Muneoki

    2012-11-20

    Moss N isotope (δ(15)N(bulk)) has been used to monitor N deposition, but it remains questionable whether inhibition of nitrate reductase activity (NRA) by reduced dissolved N (RDN) engenders overestimation of RDN in deposition when using moss δ(15)N(bulk). We tested this question by investigation of δ(15)N(bulk) and δ(15)NO(3)(-) in mosses under the dominance of RDN in N depositions of Guiyang, SW China. The δ(15)N(bulk) of mosses on bare rock (-7.9‰) was unable to integrate total dissolved N (TDN) (δ(15)N = -6.3‰), but it reflected δ(15)N-RDN (-7.5‰) exactly. Moreover, δ(15)N-NO(3)(-) in mosses (-1.7‰) resembled that of wet deposition (-1.9‰). These isotopic approximations, together with low isotopic enrichment with moss [NO(3)(-)] variations, suggest the inhibition of moss NRA by RDN. Moreover, isotopic mixing modeling indicated a negligible contribution from NO(3)(-) to moss δ(15)N(bulk) when the RDN/NO(3)(-) reaches 3.8, at which maximum overestimation (21%) of RDN in N deposition can be generated using moss δ(15)N(bulk) as δ(15)N-TDN. Moss δ(15)N-NO(3)(-) can indicate atmospheric NO(3)(-) under distinctly high RDN/NO(3)(-) in deposition, although moss δ(15)N(bulk) can reflect only the RDN therein. These results reveal pitfalls and new mechanisms associated with moss isotope monitoring of N deposition and underscore the importance of biotic N dynamics in biomonitoring studies. PMID:23050838

  2. Gas-particle partitioning of atmospheric Hg(II and its effect on global mercury deposition

    Directory of Open Access Journals (Sweden)

    H. M. Amos

    2011-10-01

    Full Text Available Atmospheric deposition represents a major input of mercury to surface environments. The phase of mercury (gas or particle has important implications for its removal from the atmosphere. We use long-term observations of reactive gaseous mercury (RGM, particle-bound mercury (PBM, fine particulate matter (PM2.5, and temperature at five sites in North America to derive an empirical gas-particle partitioning relationship log10(K-1 = (10 ± 1 − (2500 ± 300/T where K = (PBM/PM2.5/RGM with PBM and RGM in common mixing ratio units, PM2.5 in μg m−3, and T in Kelvin. This relationship is in the range of previous work but is based on far more extensive data from multiple sites. We implement this empirical relationship in the GEOS-Chem global 3-D Hg model to partition divalent mercury (Hg(II. The resulting gas-phase fraction of Hg(II ranges from over 90% in warm air with little aerosol to less than 10% in cold air with high aerosol. Hg deposition to high latitudes increases because of more efficient scavenging of particulate Hg(II by snow. Model comparison to Hg observations at surface sites suggests that subsidence from the free troposphere (warm air, low aerosol is a major factor driving the seasonality of RGM, while elevated PBM is mostly associated with high aerosol loads. This and other model updates, including the correction of an outstanding algorithm error, to wet deposition improve the simulation of Hg wet deposition fluxes in the US relative to the previous version of the model. The observed wintertime minimum in wet deposition fluxes is attributed to inefficient snow scavenging of gas-phase Hg(II.

  3. The Abundance of Atmospheric CO2 in Ocean Exoplanets: A Novel CO2 Deposition Mechanism

    CERN Document Server

    Levi, Amit; Podolak, Morris

    2016-01-01

    We consider super-Earth sized planets which have a water mass fraction that is large enough to form an external mantle composed of high pressure water ice polymorphs and that lack a substantial H/He atmosphere. We consider such planets in their habitable zone so that their outermost condensed mantle is a global deep liquid ocean. For these ocean planets we investigate potential internal reservoirs of CO2; the amount of CO2 dissolved in the ocean for the various saturation conditions encountered, and the ocean-atmosphere exchange flux of CO2. We find that in steady state the abundance of CO2 in the atmosphere has two possible states. When the wind-driven circulation is the dominant CO2 exchange mechanism, an atmosphere of tens of bars of CO2 results, where the exact value depends on the subtropical ocean surface temperature and the deep ocean temperature. When sea-ice formation, acting on these planets as a CO2 deposition mechanism, is the dominant exchange mechanism, an atmosphere of a few bars of CO2 is esta...

  4. Assessing the Emission Sources of Atmospheric Mercury in Wet Deposition Across Illinois, USA

    Directory of Open Access Journals (Sweden)

    Gratz L. E.

    2013-04-01

    Full Text Available From August 2007 to August 2009, we collected event-based precipitation samples for mercury (Hg and trace element analysis at four sites in Illinois, USA. The objectives of these measurements were to quantify the levels of Hg wet deposition across the state, and to assess the contributions to Hg in precipitation from major local and regional emission sources. The measurement sites were located in Chicago, Peoria, Nilwood, and Carbondale, IL. We were not able to identify a clear spatial gradient in Hg wet deposition among the sites. At all four locations we frequently observed Hg concentrations in precipitation > 25 ng/L, while each site received > 10 μg/m2 of Hg wet deposition annually, suggesting a substantial impact from local and regional anthropogenic emission sources. We applied the multivariate statistical receptor model Positive Matrix Factorization (PMF to the measured Hg and trace element wet deposition amounts at the four sites. The results suggested that 60-83% of total Hg deposition at each site could be attributed to coal combustion emissions. Although we identified other source signatures in the precipitation composition, including cement manufacturing, metal smelting / waste incineration, and iron-steel production, these sources contributed substantially less to the measured amounts of Hg wet deposition. We also applied the hybrid receptor model Quantitative Transport Bias Analysis (QTBA to the Hg wet deposition data from each site to identify the major source regions associated with the measured values. Results suggested that sources in the Chicago/Gary, St. Louis, and Ohio River Valley urban/industrial areas had a substantial impact on Hg wet deposition, strongly supporting the conclusion that local and regional coal combustion was the largest source of Hg wet deposition in Illinois.

  5. Atmospheric Deposition of Trace Elements in Ombrotrophic Peat as a Result of Anthropic Activities

    Science.gov (United States)

    Fabio Lourençato, Lucio; Cabral Teixeira, Daniel; Vieira Silva-Filho, Emmanoel

    2014-05-01

    Ombrotrophic peat can be defined as a soil rich in organic matter, formed from the partial decomposition of vegetable organic material in a humid and anoxic environment, where the accumulation of material is necessarily faster than the decomposition. From the physical-chemical point of view, it is a porous and highly polar material with high adsorption capacity and cation exchange. The high ability of trace elements to undergo complexation by humic substances happens due to the presence of large amounts of oxygenated functional groups in these substances. Since the beginning of industrialization human activities have scattered a large amount of trace elements in the environment. Soil contamination by atmospheric deposition can be expressed as a sum of site contamination by past/present human activities and atmospheric long-range transport of trace elements. Ombrotrophic peat records can provide valuable information about the entries of trace metals into the atmosphere and that are subsequently deposited on the soil. These trace elements are toxic, non-biodegradable and accumulate in the food chain, even in relatively low quantities. Thus studies on the increase of trace elements in the environment due to human activities are necessary, particularly in the southern hemisphere, where these data are scarce. The aims of this study is to evaluate the concentrations of mercury in ombrotrophic peat altomontanas coming from atmospheric deposition. The study is conducted in the Itatiaia National Park, Brazilian conservation unit, situated between the southeastern state of Rio de Janeiro, São Paulo and Minas Gerais. An ombrotrophic peat core is being sampled in altitude (1980m), to measure the trace elements concentrations of this material. As it is conservation area, the trace elements found in the samples is mainly from atmospheric deposition, since in Brazil don't exist significant lithology of trace elements. The samples are characterized by organic matter content which

  6. Empirical critical loads of atmospheric nitrogen deposition for nutrient enrichment and acidification of sensitive US lakes

    Science.gov (United States)

    Baron, J.S.; Driscoll, C.T.; Stoddard, J.L.; Richer, E.E.

    2011-01-01

    The ecological effects of elevated atmospheric nitrogen (N) deposition on high-elevation lakes of the western and northeastern United States include nutrient enrichment and acidification. The nutrient enrichment critical load for western lakes ranged from 1.0 to 3.0 kilograms (kg) of N per hectare (ha) per year, reflecting the nearly nonexistent watershed vegetation in complex, snowmelt-dominated terrain. The nutrient enrichment critical load for northeastern lakes ranged from 3.5 to 6.0 kg N per ha per year. The N acidification critical loads associated with episodic N pulses in waters with low values of acid neutralizing capacity were 4.0 kg N per ha per year (western) and 8.0 kg N per ha per year (northeastern). The empirical critical loads for N-caused acidification were difficult to determine because of a lack of observations in the West, and high sulfur deposition in the East. For both nutrient enrichment and acidification, the N critical load was a function of how atmospheric N deposition was determined. ?? 2011 by American Institute of Biological Sciences. All rights reserved.

  7. Influence of the nucleation layer annealing atmosphere on the resistivity of GaN grown by metalorganic chemical vapor deposition

    International Nuclear Information System (INIS)

    Graphical abstract: LT-PL spectra of GaN samples A, B and C with sheet resistance of 1.1 × 104 Ω/sq, 5.5 × 104 Ω/sq and 1.0 × 108 Ω/sq, respectively. - Highlights: • HR-GaN was fabricated by optimizing the nucleation layer annealing (NL) atmosphere. • The morphology of NLs annealed in different atmosphere has been investigated. • The resistance of GaN increased with density of edge type threading dislocations. • The PL results indicate that the HR-GaN is achieved due to the compensation of acceptor states. - Abstract: High-resistance (HR) GaN with sheet resistance of 1.0 × 108 Ω/sq was grown on sapphire substrates using metal organic chemical vapor deposition. Sheet resistance of the GaN film increases 4 orders of magnitude by changing the nucleation layer (NL) annealing atmosphere from H2 to N2. It is observed that the morphology of the NLs strongly depends on the annealing atmosphere. The analysis results based on high-resolution X-ray diffraction (HR-XRD) and etch pit density (EPD) measurements demonstrate that the density of edge-type threading dislocations increases with the proportion of the N2 in the annealing atmosphere. Photoluminescence (PL) spectra is employed to analyze the optical properties of GaN films. The XRD and PL results indicate the primary compensating mechanism is due to acceptor levels introduced by the increase in edge-type threading dislocations density. It is concluded that the annealing atmosphere of the NL controls sizes and densities of the nucleation islands, which affect electrical properties of GaN epitaxial films through changing the ratio of edge to screw/mixed-type threading dislocations

  8. Atmospheric pressure plasma enhanced chemical vapor deposition of zinc oxide and aluminum zinc oxide

    International Nuclear Information System (INIS)

    Zinc oxide (ZnO) and aluminum-doped zinc oxide (AZO) thin films were deposited via atmospheric pressure plasma enhanced chemical vapor deposition. A second-generation precursor, bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)(N,N′-diethylethylenediamine) zinc, exhibited significant vapor pressure and good stability at one atmosphere where a vaporization temperature of 110 °C gave flux ∼ 7 μmol/min. Auger electron spectroscopy confirmed that addition of H2O to the carrier gas stream mitigated F contamination giving nearly 1:1 metal:oxide stoichiometries for both ZnO and AZO with little precursor-derived C contamination. ZnO and AZO thin film resistivities ranged from 14 to 28 Ω·cm for the former and 1.1 to 2.7 Ω·cm for the latter. - Highlights: • A second generation precursor was utilized for atmospheric pressure film growth. • Addition of water vapor to the carrier gas stream led to a marked reduction of ZnF2. • Carbonaceous contamination from the precursor was minimal

  9. Atmospheric Deposition of Organic Carbon in Pennsylvania as Affected by Climatic Factors

    Science.gov (United States)

    Iavorivska, L.; Boyer, E. W.; Grimm, J.; Fuentes, J. D.

    2014-12-01

    Organic matter which is usually expressed through measurements of dissolved organic carbon (DOC) is ubiquitous in atmospheric water. It plays an important role in cloud formation processes, and contributes to organic acidity of precipitation. Rain and snow deposited to the landscape is a source of nutrient enrichment to ecosystems and water bodies, and is especially important as an input of carbon in coastal regions. Since DOC is highly chemically reactive and bioavailable it influences rates of primary and secondary productivity in aquatic ecosystems. Despite the significance of DOC to many ecosystem processes, knowledge about its contributions to landscapes in precipitation remains limited. Here, we quantified the removal of DOC from the atmosphere via precipitation over space and time in order to assess the magnitude of wet deposition as a link between terrestrial and aquatic components of the carbon cycle. Further, we consider the predictability of organic matter in precipitation as a function of hydro-chemical and climatic variables. We measured DOC concentration and composition in storm events both sequentially (hourly during events) and seasonally (weekly over the year). Data on the chemical composition of precipitation, along with meteorological back-trajectory analyses help clarify how an interplay between emission sources, atmospheric transport and climatic conditions determine the abundance of rainwater DOC across Pennsylvania.

  10. Impact of biomass burning on ocean water quality in Southeast Asia through atmospheric deposition: field observations

    Science.gov (United States)

    Sundarambal, P.; Balasubramanian, R.; Tkalich, P.; He, J.

    2010-12-01

    Atmospheric nutrients have recently gained considerable attention as a significant additional source of new nitrogen (N) and phosphorus (P) loading to the ocean. The effect of atmospheric macro nutrients on marine productivity depends on the biological availability of both inorganic and organic N and P forms. During October 2006, the regional smoke haze episodes in Southeast Asia (SEA) that resulted from uncontrolled forest and peat fires in Sumatra and Borneo blanketed large parts of the region. In this work, we determined the chemical composition of nutrients in aerosols and rainwater during hazy and non-hazy days to assess their impacts on aquatic ecosystem in SEA for the first time. We compared atmospheric dry and wet deposition of N and P species in aerosol and rainwater in Singapore between hazy and non-hazy days. Air mass back trajectories showed that large-scale forest and peat fires in Sumatra and Kalimantan were a significant source of atmospheric nutrients to aquatic environments in Singapore and SEA region on hazy days. It was observed that the average concentrations of nutrients increased approximately by a factor of 3 to 8 on hazy days when compared with non-hazy days. The estimated mean dry and wet atmospheric fluxes (mg/m2/day) of total nitrogen (TN) were 12.72 ± 2.12 and 2.49 ± 1.29 during non-hazy days and 132.86 ± 38.39 and 29.43 ± 10.75 during hazy days; the uncertainty estimates are represented as 1 standard deviation (1σ) here and throughout the text. The estimated mean dry and wet deposition fluxes (mg/m2/day) of total phosphorous (TP) were 0.82 ± 0.23 and 0.13 ± 0.03 for non-hazy days and 7.89 ± 0.80 and 1.56 ± 0.65 for hazy days. The occurrences of higher concentrations of nutrients from atmospheric deposition during smoke haze episodes may have adverse consequences on receiving aquatic ecosystems with cascading impacts on water quality.

  11. Xenon-133 and caesium-137 releases into the atmosphere from the Fukushima Dai-ichi nuclear power plant: determination of the source term, atmospheric dispersion, and deposition

    Directory of Open Access Journals (Sweden)

    A. Stohl

    2011-10-01

    Full Text Available On 11 March 2011, an earthquake occurred about 130 km off the Pacific coast of Japan's main island Honshu, followed by a large tsunami. The resulting loss of electric power at the Fukushima Dai-ichi nuclear power plant (FD-NPP developed into a disaster causing massive release of radioactivity into the atmosphere. In this study, we determine the emissions of two isotopes, the noble gas xenon-133 (133Xe and the aerosol-bound caesium-137 (137Cs, which have very different release characteristics as well as behavior in the atmosphere. To determine radionuclide emissions as a function of height and time until 20 April, we made a first guess of release rates based on fuel inventories and documented accident events at the site. This first guess was subsequently improved by inverse modeling, which combined the first guess with the results of an atmospheric transport model, FLEXPART, and measurement data from several dozen stations in Japan, North America and other regions. We used both atmospheric activity concentration measurements as well as, for 137Cs, measurements of bulk deposition. Regarding 133Xe, we find a total release of 16.7 (uncertainty range 13.4–20.0 EBq, which is the largest radioactive noble gas release in history not associated with nuclear bomb testing. There is strong evidence that the first strong 133Xe release started very early, possibly immediately after the earthquake and the emergency shutdown on 11 March at 06:00 UTC. The entire noble gas inventory of reactor units 1–3 was set free into the atmosphere between 11 and 15 March 2011. For 137Cs, the inversion results give a total emission of 35.8 (23.3–50.1 PBq, or about 42% of the estimated Chernobyl emission. Our results indicate that 137Cs emissions peaked on 14–15 March but were generally high from 12 until 19 March, when they suddenly dropped by orders of magnitude exactly when spraying of

  12. Atmospheric wet deposition of trace elements to a suburban environment, Reston, Virginia, USA

    Science.gov (United States)

    Conko, K.M.; Rice, K.C.; Kennedy, M.M.

    2004-01-01

    Wet deposition from a suburban area in Reston, Virginia was collected during 1998 and analyzed to assess the anion and trace-element concentrations and depositions. Suburban Reston, approximately 26km west of Washington, DC, is densely populated and heavily developed. Wet deposition was collected bi-weekly in an automated collector using trace-element clean sampling and analytical techniques. The annual volume-weighted concentrations of As, Cd, and Pb were similar to those previously reported for a remote site on Catoctin Mt., Maryland (70km northwest), which indicated a regional signal for these elements. The concentrations and depositions of Cu and Zn at the suburban site were nearly double those at remote sites because of the influence of local vehicular traffic. The 1998 average annual wet deposition (??gm-2yr -1) was calculated for Al (52,000), As (94), Cd (54), Cr (160), Cu (700), Fe (23,000), Mn (2000), Ni (240), Pb (440), V (430), and Zn (4100). The average annual wet deposition (meqm-2yr-1) was calculated for H+ (74), Cl- (8.5), NO3- (33), and SO42- (70). Analysis of digested total trace-element concentrations in a subset of samples showed that the refractory elements in suburban precipitation comprised a larger portion of the total deposition of trace elements than in remote areas. ?? 2004 Elsevier Ltd. All rights reserved.

  13. Atmospheric Mg2+ wet deposition within the continental United States and implications for soil inorganic carbon sequestration

    OpenAIRE

    Goddard, Megan A.; Mikhailova, Elena A.; Post, Christopher J.; Schlautman, Mark A.

    2011-01-01

    Little is known about atmospheric magnesium ion (Mg2+) wet deposition in relation to soil inorganic carbon sequestration. Understanding the conversion of carbon dioxide (CO2) or organic carbon to a form having a long residence time within the soil (e.g., dolomite, magnesian calcite) will greatly benefit agriculture, industry, and society on a global scale. This preliminary study was conducted to analyze atmospheric Mg2+ wet deposition within the continental United States (U.S.) and to rank th...

  14. Current state and temporal evolution of the chemical composition of atmospheric depositions in forest areas of the CONECOFOR network

    OpenAIRE

    Marchetto A; Arisci S.; Tartari GA; Balestrini R; Tait D

    2014-01-01

    Current state and temporal evolution of the chemical composition of atmospheric depositions in forest areas of the CONECOFOR network. Since 1997, atmospheric deposition was sampled and analyzed in the permanent plots of the Italian network for the evaluation of forest health (CONECOFOR), under the coordination of the Italian Forest Service. This paper presents the results of the activity carried out in 2009, when the EU-funded LIFE+ “FutMon” project allowed to extend the sampling network to 2...

  15. Atmospheric salt deposition in a tropical mountain rainforest at the eastern Andean slopes of south Ecuador - Pacific or Atlantic origin?

    Science.gov (United States)

    Makowski Giannoni, Sandro; Trachte, Katja; Rollenbeck, Ruetger; Lehnert, Lukas; Fuchs, Julia; Bendix, Joerg

    2016-08-01

    Sea salt (NaCl) has recently been proven to be of the utmost importance for ecosystem functioning in Amazon lowland forests because of its impact on herbivory, litter decomposition and, thus, carbon cycling. Sea salt deposition should generally decline as distance from its marine source increases. For the Amazon, a negative east-west gradient of sea salt availability is assumed as a consequence of the barrier effect of the Andes Mountains for Pacific air masses. However, this generalized pattern may not hold for the tropical mountain rainforest in the Andes of southern Ecuador. To analyse sea salt availability, we investigated the deposition of sodium (Na+) and chloride (Cl-), which are good proxies of sea spray aerosol. Because of the complexity of the terrain and related cloud and rain formation processes, sea salt deposition was analysed from both, rain and occult precipitation (OP) along an altitudinal gradient over a period between 2004 and 2009. To assess the influence of easterly and westerly air masses on the deposition of sodium and chloride over southern Ecuador, sea salt aerosol concentration data from the Monitoring Atmospheric Composition and Climate (MACC) reanalysis data set and back-trajectory statistical methods were combined. Our results, based on deposition time series, show a clear difference in the temporal variation of sodium and chloride concentration and Na+ / Cl- ratio in relation to height and exposure to winds. At higher elevations, sodium and chloride present a higher seasonality and the Na+ / Cl- ratio is closer to that of sea salt. Medium- to long-range sea salt transport exhibited a similar seasonality, which shows the link between our measurements at high elevations and the sea salt synoptic transport. Although the influence of the easterlies was predominant regarding the atmospheric circulation, the statistical analysis of trajectories and hybrid receptor models revealed a stronger impact of the north equatorial Atlantic, Caribbean

  16. The importance of source configuration in quantifying footprints of regional atmospheric sulphur deposition.

    Science.gov (United States)

    Vieno, M; Dore, A J; Bealey, W J; Stevenson, D S; Sutton, M A

    2010-01-15

    An atmospheric transport-chemistry model is applied to investigate the effects of source configuration in simulating regional sulphur deposition footprints from elevated point sources. Dry and wet depositions of sulphur are calculated for each of the 69 largest point sources in the UK. Deposition contributions for each point source are calculated for 2003, as well as for a 2010 emissions scenario. The 2010 emissions scenario has been chosen to simulate the Gothenburg protocol emission scenario. Point source location is found to be a major driver of the dry/wet deposition ratio for each deposition footprint, with increased precipitation scavenging of SO(x) in hill areas resulting in a larger fraction of the emitted sulphur being deposited within the UK for sources located near these areas. This reduces exported transboundary pollution, but, associated with the occurrence of sensitive soils in hill areas, increases the domestic threat of soil acidification. The simulation of plume rise using individual stack parameters for each point source demonstrates a high sensitivity of SO(2) surface concentration to effective source height. This emphasises the importance of using site-specific information for each major stack, which is rarely included in regional atmospheric pollution models, due to the difficulty in obtaining the required input data. The simulations quantify how the fraction of emitted SO(x) exported from the UK increases with source magnitude, effective source height and easterly location. The modelled reduction in SO(x) emissions, between 2003 and 2010 resulted in a smaller fraction being exported, with the result that the reductions in SO(x) deposition to the UK are less than proportionate to the emission reduction. This non-linearity is associated with a relatively larger fraction of the SO(2) being converted to sulphate aerosol for the 2010 scenario, in the presence of ammonia. The effect results in less-than-proportional UK benefits of reducing in SO(2

  17. Characterisation of atmospheric deposition as a source of contaminants in urban rainwater tanks.

    Science.gov (United States)

    Huston, R; Chan, Y C; Gardner, T; Shaw, G; Chapman, H

    2009-04-01

    To characterise atmospheric input of chemical contaminants to urban rainwater tanks, bulk deposition (wet+dry deposition) was collected at sixteen sites in Brisbane, Queensland, Australia on a monthly basis during April 2007-March 2008 (N=175). Water from rainwater tanks (22 sites, 26 tanks) was also sampled concurrently. The deposition/tank water was analysed for metals, soluble anions and selected samples were additionally analysed for PAHs, pesticides, phenols, organic & inorganic carbon. Flux (mg/m(2)/d) of total solids mass was found to correlate with average daily rainfall (R(2)=0.49) indicating the dominance of the wet deposition contribution to total solids mass. On average 97% of the total mass of analysed components was accounted for by Cl(-) (25.0%), Na (22.6%), organic carbon (20.5%), NO(3)(-) (10.5%), SO(4)(2-) (9.8%), inorganic carbon (5.7%), PO(4)(3-) (1.6%) and NO(2)(-) (1.5%). For other minor elements the average flux from highest to lowest was in the order of Fe>Al>Zn>Mn>Sr>Pb>Ba>Cu>Se. There was a significant effect of location on flux of K, Sb, Sn, Li, Mn, Fe, Cu, Zn, Ba, Pb and SO(4)(2-) but not other metals or anions. Overall the water quality resulting from the deposition (wet+dry) was good but 10.3%, 1.7% and 17.7% of samples had concentrations of Pb, Cd and Fe respectively greater than the Australian Drinking Water Guidelines (ADWG). This generally occurred in the drier months. In comparison 14.2% and 6.1% of tank samples had total Pb and Zn concentrations exceeding the guidelines. The cumulative mean concentration of lead in deposition was on average only 1/4 of that in tank water over the year at a site with high concentrations of Pb in tank water. This is an indication that deposition from the atmosphere is not the major contributor to high lead concentrations in urban rainwater tanks in a city with reasonable air quality, though it is still a significant portion. PMID:19171360

  18. The importance of source configuration in quantifying footprints of regional atmospheric sulphur deposition.

    Science.gov (United States)

    Vieno, M; Dore, A J; Bealey, W J; Stevenson, D S; Sutton, M A

    2010-01-15

    An atmospheric transport-chemistry model is applied to investigate the effects of source configuration in simulating regional sulphur deposition footprints from elevated point sources. Dry and wet depositions of sulphur are calculated for each of the 69 largest point sources in the UK. Deposition contributions for each point source are calculated for 2003, as well as for a 2010 emissions scenario. The 2010 emissions scenario has been chosen to simulate the Gothenburg protocol emission scenario. Point source location is found to be a major driver of the dry/wet deposition ratio for each deposition footprint, with increased precipitation scavenging of SO(x) in hill areas resulting in a larger fraction of the emitted sulphur being deposited within the UK for sources located near these areas. This reduces exported transboundary pollution, but, associated with the occurrence of sensitive soils in hill areas, increases the domestic threat of soil acidification. The simulation of plume rise using individual stack parameters for each point source demonstrates a high sensitivity of SO(2) surface concentration to effective source height. This emphasises the importance of using site-specific information for each major stack, which is rarely included in regional atmospheric pollution models, due to the difficulty in obtaining the required input data. The simulations quantify how the fraction of emitted SO(x) exported from the UK increases with source magnitude, effective source height and easterly location. The modelled reduction in SO(x) emissions, between 2003 and 2010 resulted in a smaller fraction being exported, with the result that the reductions in SO(x) deposition to the UK are less than proportionate to the emission reduction. This non-linearity is associated with a relatively larger fraction of the SO(2) being converted to sulphate aerosol for the 2010 scenario, in the presence of ammonia. The effect results in less-than-proportional UK benefits of reducing in SO(2

  19. Characterisation of atmospheric deposition as a source of contaminants in urban rainwater tanks.

    Science.gov (United States)

    Huston, R; Chan, Y C; Gardner, T; Shaw, G; Chapman, H

    2009-04-01

    To characterise atmospheric input of chemical contaminants to urban rainwater tanks, bulk deposition (wet+dry deposition) was collected at sixteen sites in Brisbane, Queensland, Australia on a monthly basis during April 2007-March 2008 (N=175). Water from rainwater tanks (22 sites, 26 tanks) was also sampled concurrently. The deposition/tank water was analysed for metals, soluble anions and selected samples were additionally analysed for PAHs, pesticides, phenols, organic & inorganic carbon. Flux (mg/m(2)/d) of total solids mass was found to correlate with average daily rainfall (R(2)=0.49) indicating the dominance of the wet deposition contribution to total solids mass. On average 97% of the total mass of analysed components was accounted for by Cl(-) (25.0%), Na (22.6%), organic carbon (20.5%), NO(3)(-) (10.5%), SO(4)(2-) (9.8%), inorganic carbon (5.7%), PO(4)(3-) (1.6%) and NO(2)(-) (1.5%). For other minor elements the average flux from highest to lowest was in the order of Fe>Al>Zn>Mn>Sr>Pb>Ba>Cu>Se. There was a significant effect of location on flux of K, Sb, Sn, Li, Mn, Fe, Cu, Zn, Ba, Pb and SO(4)(2-) but not other metals or anions. Overall the water quality resulting from the deposition (wet+dry) was good but 10.3%, 1.7% and 17.7% of samples had concentrations of Pb, Cd and Fe respectively greater than the Australian Drinking Water Guidelines (ADWG). This generally occurred in the drier months. In comparison 14.2% and 6.1% of tank samples had total Pb and Zn concentrations exceeding the guidelines. The cumulative mean concentration of lead in deposition was on average only 1/4 of that in tank water over the year at a site with high concentrations of Pb in tank water. This is an indication that deposition from the atmosphere is not the major contributor to high lead concentrations in urban rainwater tanks in a city with reasonable air quality, though it is still a significant portion.

  20. Atmospheric particle characterization, distribution, and deposition in Xi'an, Shaanxi Province, Central China.

    Science.gov (United States)

    Cao, Zongze; Yang, Yuhua; Lu, Julia; Zhang, Chengxiao

    2011-02-01

    Physical characterization and chemical analysis of settled dusts collected in Xi'an from November 2007 to December 2008 show that (1) dust deposition rates ranged from 14.6 to 350.4 g m(-2) yr(-1). The average deposition rate (76.7 g m(-2) yr(-1)) ranks the 11th out of 56 dust deposition rates observed throughout the world. The coal-burning power was the major particle source; (2) on average (except site 4), ∼10% of the settled dusts having size 70% having size deposition rates of dusts that contain elevated levels of toxic elements, actions should be taken to reduce emission and studies are needed to assess the potential impacts of settled particles on surface ecosystem, water resource, and human health in the area.

  1. Two high resolution terrestrial records of atmospheric Pb deposition from New Brunswick, Canada, and Loch Laxford, Scotland

    International Nuclear Information System (INIS)

    Environmental archives like peat deposits allow for the reconstruction of both naturally and anthropogenically forced changes in the biogeochemical cycle of Pb as well as the quantification of past and present atmospheric Pb pollution. However, records of atmospheric Pb deposition from pre-industrial times are lacking. In a publication by Weiss et al. [Weiss, D., Shotyk, W., Boyle, E.A., Kramers, J.D., Appleby, P.G., Cheburkin, A.K., Comparative study of the temporal evolution of atmospheric lead deposition in Scotland and eastern Canada using blanket peat bogs. Sci Total Environ 2002;292:7-18]. Pb isotopes data measured by Q-ICP-MS and TIMS, concentration and enrichment data was presented for sites in eastern Canada (PeW1) and northwestern Scotland (LL7c), dating to 1586 A.D and 715 A.D., respectively. Here these same cores are re-analysed for Pb isotopes by MC-ICP-MS thereby acquiring 204Pb data and improving on the original data in terms of resolution and temporal coverage. Significant differences were found between the Q-ICP-MS/TIMS and MC-ICP-MS measurements, particularly at PeW1. These discrepancies are attributed to the problematic presence of organic matter during sample preparation and analysis complicated by the heterogeneity of the organic compounds that survived sample preparation steps. The precision and accuracy of Pb isotopes in complex matrices like peat is not always well estimated by industrial standards like NIST-SRM 981 Pb. Lead pollution histories at each site were constructed using the MC-ICP-MS data. The entire LL7c record is likely subject to anthropogenic additions. Contributions from local mining were detected in Medieval times. Later, coal use and mining in Scotland, Wales and England became important. After industrialization (ca. 1885 A.D.) contributions from Broken Hill type ores and hence, leaded petrol, dominate atmospheric Pb signatures right up to modern times. At PeW1 anthropogenic impacts are first distinguishable in the late 17th

  2. Two high resolution terrestrial records of atmospheric Pb deposition from New Brunswick, Canada, and Loch Laxford, Scotland

    Energy Technology Data Exchange (ETDEWEB)

    Kylander, Malin E. [Department of Geology and Geochemistry, Stockholm University, 10691 Stockholm (Sweden)], E-mail: malin.kylander@geo.su.se; Weiss, Domink J. [Department of Earth Science and Engineering, Imperial College London, SW7 2AZ (United Kingdom); Department of Mineralogy, The Natural History Museum, London, SW7 5BD (United Kingdom)], E-mail: d.weiss@imperial.ac.uk; Kober, Bernd [Institute of Earth Sciences, University of Heidelberg, Im Neuenheimer Feld 234-236, D-69120 Heidelberg (Germany)], E-mail: bernd.kober@urz.uni-heidelberg.de

    2009-02-15

    Environmental archives like peat deposits allow for the reconstruction of both naturally and anthropogenically forced changes in the biogeochemical cycle of Pb as well as the quantification of past and present atmospheric Pb pollution. However, records of atmospheric Pb deposition from pre-industrial times are lacking. In a publication by Weiss et al. [Weiss, D., Shotyk, W., Boyle, E.A., Kramers, J.D., Appleby, P.G., Cheburkin, A.K., Comparative study of the temporal evolution of atmospheric lead deposition in Scotland and eastern Canada using blanket peat bogs. Sci Total Environ 2002;292:7-18]. Pb isotopes data measured by Q-ICP-MS and TIMS, concentration and enrichment data was presented for sites in eastern Canada (PeW1) and northwestern Scotland (LL7c), dating to 1586 A.D and 715 A.D., respectively. Here these same cores are re-analysed for Pb isotopes by MC-ICP-MS thereby acquiring {sup 204}Pb data and improving on the original data in terms of resolution and temporal coverage. Significant differences were found between the Q-ICP-MS/TIMS and MC-ICP-MS measurements, particularly at PeW1. These discrepancies are attributed to the problematic presence of organic matter during sample preparation and analysis complicated by the heterogeneity of the organic compounds that survived sample preparation steps. The precision and accuracy of Pb isotopes in complex matrices like peat is not always well estimated by industrial standards like NIST-SRM 981 Pb. Lead pollution histories at each site were constructed using the MC-ICP-MS data. The entire LL7c record is likely subject to anthropogenic additions. Contributions from local mining were detected in Medieval times. Later, coal use and mining in Scotland, Wales and England became important. After industrialization (ca. 1885 A.D.) contributions from Broken Hill type ores and hence, leaded petrol, dominate atmospheric Pb signatures right up to modern times. At PeW1 anthropogenic impacts are first distinguishable in the

  3. Assessing the emission sources of atmospheric mercury in wet deposition across Illinois.

    Science.gov (United States)

    Gratz, Lynne E; Keeler, Gerald J; Morishita, Masako; Barres, James A; Dvonch, J Timothy

    2013-03-15

    From August 4, 2007 to August 31, 2009, we collected event-based precipitation samples for mercury (Hg) and trace element analyses at four sites in Illinois (IL), USA. The objectives of these measurements were to quantify Hg wet deposition across the state, and to assess the contributions to Hg in precipitation from major local and regional emission sources. Monitoring sites were located, from north to south, in Chicago, Peoria, Nilwood, and Carbondale, IL. Measurements from these four sites demonstrated that a clear spatial gradient in Hg wet deposition was not evident across the state. Each site received>10μgm(-2) of Hg wet deposition annually, and these observed values were comparable to annual Hg wet deposition measurements from other event-based precipitation monitoring sites in source-impacted areas of the Midwestern U.S. We applied the multivariate statistical receptor model, Positive Matrix Factorization (EPA PMF v3.0), to the measured Hg and trace element wet deposition amounts at the four sites. Results suggested that 50% to 74% of total Hg wet deposition at each site could be attributed to coal combustion emissions. The other source signatures identified in the precipitation compositions included cement manufacturing, mixed metal smelting/waste incineration, iron-steel production, and a phosphorus source. We also applied a hybrid receptor model, Quantitative Transport Bias Analysis (QTBA), to the Hg wet deposition datasets to identify the major source regions associated with the measured values. The calculated QTBA probability fields suggested that transport from urban/industrial areas, such as Chicago/Gary, St. Louis, and the Ohio River Valley, resulted in some of the highest estimated event-based Hg wet deposition amounts at the four sites (potential mass transfer of up to 0.32μgm(-2)). The combined application of PMF and QTBA supported the hypothesis that local and regional coal combustion was the largest source of Hg wet deposition in Illinois

  4. Atmospheric pressure chemical vapor deposition (APCVD) grown bi-layer graphene transistor characteristics at high temperature

    KAUST Repository

    Qaisi, Ramy M.

    2014-05-15

    We report the characteristics of atmospheric chemical vapor deposition grown bilayer graphene transistors fabricated on ultra-scaled (10 nm) high-κ dielectric aluminum oxide (Al2O3) at elevated temperatures. We observed that the drive current increased by >400% as temperature increased from room temperature to 250 °C. Low gate leakage was maintained for prolonged exposure at 100 °C but increased significantly at temperatures >200 °C. These results provide important insights for considering chemical vapor deposition graphene on aluminum oxide for high temperature applications where low power and high frequency operation are required. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Time Invariant Surface Roughness Evolution during Atmospheric Pressure Thin Film Depositions.

    Science.gov (United States)

    Merkh, Thomas; Spivey, Robert; Lu, Toh Ming

    2016-01-01

    The evolution of thin film morphology during atmospheric pressure deposition has been studied utilizing Monte Carlo methods. Time invariant root-mean-squared roughness and local roughness morphology were both observed when employing a novel simulation parameter, modeling the effect of the experimental high pressure condition. This growth regime, where the surface roughness remains invariant after reaching a critical value, has not been classified by any existing universality class. An anti-shadowing growth mechanism responsible for this regime occurs when particles undergo binary collisions beneath the surface apexes. Hence, this mechanism is applicable when the mean free path of the depositing species is comparable to the amplitude of the surface features. Computationally this has been modeled by allowing particles to change direction at a specified height above the local film surface. This modification of the incoming flux trajectory consequently has a dramatic smoothening effect, and the resulting surfaces appear in agreement with recent experimental observations. PMID:26814165

  6. Atmospheric vapor phase deposition of nanometer-thick anti-stiction fluoropolymer coatings for silicon surfaces

    Science.gov (United States)

    Itoh, Shintaro; Takahashi, Kazuhiro; Morita, Hiroyuki; Fukuzawa, Kenji; Zhang, Hedong

    2016-06-01

    Anti-stiction coatings for silicon surfaces are a key technology to prevent the failure of nanoelectromechanical systems (NEMS) during operation and improve the forming accuracy in nanoimprint technology. In this study, we propose an atmospheric vapor phase deposition method to coat a silicon surface with fluoropolymers such as the perfluoropolyethers Fomblin Zdol 2000 and Zdol 4000. Thickness distributions, surface energies, coverages, and stiction forces for the deposited films were evaluated experimentally. The proposed method resulted in over 90% coverage with a film thickness of about 1 nm. The film thickness uniformity was around 0.1 nm over an area of 5 × 5 mm2. This coating effectively reduced the stiction forces by half compared with a bare silicon surface.

  7. Spatio-temporal variations of atmospheric heavy metal deposition in the Lisbon area by moss monitoring

    International Nuclear Information System (INIS)

    The use of mosses as biomonitors of heavy metal deposition has been extensively applied in numerous studies in the last three decades. This type of organisms acquires almost their nutrients from the atmosphere, by dry or wet deposition. In Portugal, the first biomonitoring survey using mosses was done in 1992, which covered all national area. A new study is presently being implemented, where samples are collected in the same sampling points of the previous ones, so a comparison can be made between the results of the two campaigns. This work presents the results obtained for the Lisbon region. Samples of Hypnum cupressiforme, or whenever unavailable, Scleropodium touretii were collected in 27 sites in this area, and the concentration of Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn was determined for each sample. Maps for each element were drawn after geostatistical estimation of the metal concentration in the moss. The spatial and temporal variations in the distribution of metal concentration are discussed. (author)

  8. Deposition of heavy water on soil and reemission to the atmosphere

    International Nuclear Information System (INIS)

    Field experiments using heavy water as a tracer instead of tritiated water (HTO) were carried out in November 1995 and August 1996 in Japan. The objective of these experiments was to estimate the behavior of HTO in the environment when HTO was released to the atmosphere. We measured the evolution of depth profiles of heavy water concentrations in soil water and compared the reemission rates with the evaporation velocities to study the deposition and reemission of heavy water to/from soil. The depth profiles of heavy water concentrations in soil were expressed by exponential functions of which the gradient depended on the deposition period. The initial reemission rates of heavy water from the soil were the highest, regardless of the meteorological conditions. The reemission occurred not only during the day but also at night, suggesting that the exchange of heavy water in the soil surface layer with H2O in air played a dominant role during nighttime. (orig.)

  9. Influence of NaCl Deposition on Atmospheric Corrosion of A3 Steel

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Regularity of the initial atmospheric corrosion of A3 steel in the presence of NaCl was investigated. The results showed that NaCl can accelerate the corrosion of A3 steel. Dry mass gain of A3 steel in the presence of NaCl deposition increases with the exposure time, which can be correlated by using exponential decay function. The relationship between dry mass gain and amount of NaCl deposition at a certain exposure time follows a quadratic function. More amount of NaCl deposition will slow down the corrosion rate to some extent after exposure for a certain time. SEM/EDAX was used to characterize the corrosion surface and products. The surfaces of the NaCl treated A3 steel were obviously uneven, and some tiny crevices appear in the corrosion products that could help O2 transmit to the inner layer. The amount of oxygen in atomic percentage in the corrosion products increases with the amount of NaCl deposition.

  10. Riverine Response of Sulfate to Declining Atmospheric Sulfur Deposition in Agricultural Watersheds.

    Science.gov (United States)

    David, Mark B; Gentry, Lowell E; Mitchell, Corey A

    2016-07-01

    Sulfur received extensive study as an input to terrestrial ecosystems from acidic deposition during the 1980s. With declining S deposition inputs across the eastern United States, there have been many studies evaluating ecosystem response, with the exception of agricultural watersheds. We used long-term (22 and 18 yr) sulfate concentration data from two rivers and recent (6 yr) data from a third river to better understand cycling and transport of S in agricultural, tile-drained watersheds. Sulfate concentrations and yields steadily declined in the Embarras (from ∼10 to 6 mg S L) and Kaskaskia rivers (from 7 to 3.5 mg S L) during the sampling period, with an overall -23.1 and -12.8 kg S ha yr balance for the two watersheds. There was evidence of deep groundwater inputs of sulfate in the Salt Fork watershed, with a much smaller input to the Embarras and none to the Kaskaskia. Tiles in the watersheds had low sulfate concentrations (fertilizer. A multiple regression model of runoff (cm) and S deposition explained much of the variation in Embarras River sulfate ( = 0.86 and 0.80 for concentrations and yields; = 46). Although atmospheric deposition was much less than outputs (grain harvest + stream export of sulfate), riverine transport of sulfate reflected the decline in inputs. Watershed S balances suggest a small annual depletion of soil organic S pools, and S fertilization will likely be needed at some future date to maintain crop yields. PMID:27380080

  11. Atmospheric pressure spatial atomic layer deposition web coating with in situ monitoring of film thickness

    International Nuclear Information System (INIS)

    Spectral reflectometry was implemented as a method for in situ thickness monitoring in a spatial atomic layer deposition (ALD) system. Al2O3 films were grown on a moving polymer web substrate at 100 °C using an atmospheric pressure ALD web coating system, with film growth of 0.11–0.13 nm/cycle. The modular coating head design and the in situ monitoring allowed for the characterization and optimization of the trimethylaluminum and water precursor exposures, purge flows, and web speed. A thickness uniformity of ±2% was achieved across the web. ALD cycle times as low as 76 ms were demonstrated with a web speed of 1 m/s and a vertical gap height of 0.5 mm. This atmospheric pressure ALD system with in situ process control demonstrates the feasibility of low-cost, high throughput roll-to-roll ALD

  12. Optical properties of metal oxynitride thin films grown with atmospheric plasma deposition

    Science.gov (United States)

    Hovish, Michael Q.; Dauskardt, Reinhold H.

    2016-10-01

    Thin films of tantalum oxynitride (TaO x N y ) and titanium oxynitride (TiO x N y ) are deposited using atmospheric plasma deposition and a suite of optical properties are reported. Tantalum and titanium ethoxide are introduced into the afterglow of a radio-frequency capacitively coupled plasma, facilitating the growth of oxynitride films on silicon and polycarbonate at temperatures below 180 °C. The plasma power and nitrogen flow within the plasma are varied between 60 and 120 W and between 0.1 and 0.3 LPM respectively. We use spectroscopic ellipsometry to show that the optical properties of the metal oxynitride films grown in this study are comparable to those synthesized with sol-gel methods. Measurement of both the extinction coefficient and the transmission on polycarbonate substrates indicates good transparency in the visible wavelengths of light. Additionally, the refractive index increases when increasing the number of reactive nitrogen species within the discharge. We use x-ray photoelectron spectroscopy to correlate the higher indexes observed at large secondary gas flows to the presence of metal oxynitride bonding. Single layer anti-reflection coatings are deposited on silicon, with a five-fold and seven-fold reduction in reflection for TaO x N y and TiO x N y coatings, respectively. In total, we have found that the modulation of nitrogen concentration within the plasma discharge results in good control over optical constants. In addition, we observe similarities between films deposited with atmospheric plasma and those reported for sol-gel, indicating an alternative processing route where solution chemistries are currently applied.

  13. Background atmospheric sulfate deposition at a remote alpine site in the Southern Canadian Rocky Mountains

    Science.gov (United States)

    Wasiuta, Vivian; Norman, Ann-Lise; Lafrenière, Melissa J.; Hastings, Meredith G.

    2015-11-01

    We report observations of stable isotope ratios and ion concentrations from seasonal snowpack and summer bulk precipitation from remote alpine sites in the Southern Canadian Rocky Mountains. Spatial deposition patterns for sulfur (S) and δ34S-SO42- values indicate dominantly distant sources with little impact from local to regional pollution. Comparable S loads and total snowpack δ34S-SO42- values for glacier snowpack indicates S emissions were well mixed prior to dry deposition or incorporation into snowfall. A uniform S load and similar δ34S-SO42- values in a detailed study of summer bulk precipitation implies well-mixed distant emissions. We interpret the deposited 0.9 kg S ha-1yr-1 as atmospheric background deposition in midlatitude Western Canada. This study will improve calculations for sites impacted by point source emissions and provide a baseline for attributing changes associated with climate change, industrialization, and urban growth. Field evidence from this study supports theoretical and laboratory research on the relative importance of oxidation pathways on atmospheric δ34S-SO42- values for long-range transported sulfate. δ34S-SO42- of the dominant S source in summer bulk precipitation (~ +2‰) versus snowpack (≥ +9‰) cannot be explained by seasonal emission sources, temperature effects on fractionation, or Rayleigh distillation. The study supports a seasonal difference in the relative importance of the different SO2 to SO42- oxidation pathways with homogeneous oxidation by OH and heterogeneous oxidation by H2O2 most important in summer, and O2 catalyzed by transition metal ions in a radical chain reaction pathway more significant in winter.

  14. Deposition of flux and atmospheric behavior of oil shale combustion aerosols

    International Nuclear Information System (INIS)

    The atmospheric behavior of oil shale combustion fly ash aerosol was studied under simulated conditions. The fine (respirable) fraction of fly ash particles, which contributes most to the health effects of the aerosol, significantly increased (from 25 to 65 % by mass) in time scale. The toxic elements and carcinogenic PAH adsorbed on the fine particles of fly ash could represent a health hazard for human. The bulk and trace elements in emissions (flue gases) and integrated deposition samples were also investigated based on original measurements and literature data. (author)

  15. Fabrication of transparent antifouling thin films with fractal structure by atmospheric pressure cold plasma deposition.

    Science.gov (United States)

    Miyagawa, Hayato; Yamauchi, Koji; Kim, Yoon-Kee; Ogawa, Kazufumi; Yamaguchi, Kenzo; Suzaki, Yoshifumi

    2012-12-21

    Antifouling surface with both superhydrophobicity and oil-repellency has been fabricated on glass substrate by forming fractal microstructure(s). The fractal microstructure was constituted by transparent silica particles of 100 nm diameter and transparent zinc-oxide columns grown on silica particles by atmospheric pressure cold plasma deposition. The sample surface was coated with a chemically adsorbed monomolecular layer. We found that one sample has the superhydrophobic ability with a water droplet contact angle of more than 150°, while another sample has a high transmittance of more than 85% in a wavelength range from 400 to 800 nm.

  16. Atmospheric pressure chemical vapor deposition of CdTe—reactor design considerations

    Science.gov (United States)

    Meyers, Peter V.; Kee, Robert J.; Raja, Laxminarayan; Wolden, Colin A.; Aire, Michael

    1999-03-01

    Atmospheric Pressure Chemical Vapor Deposition (APCVD) of polycrystalline thin-film CdTe appears to offer several practical advantages over state-of-the-art manufacturing techniques. APCVD employs the same reaction chemistry utilized to produce 16% efficient CdTe cells (i.e., same reaction chemistry as Close Spaced Sublimation), avoids use of vacuum equipment, allows for physical separation of the source and substrate, and employs forced convection to ensure uniform delivery of source material over large-area substrates. Reactor design considerations and preliminary numerical simulations of mass transport are presented.

  17. Forest condition and chemical characteristics of atmospheric depositions: research and monitoring network in Lombardy

    Directory of Open Access Journals (Sweden)

    Flaminio DI GIROLAMO

    2002-09-01

    Full Text Available Since 1987, the Regional Forestry Board of Lombardy and the Water Research Institute of the National Research Council have been carrying out surveys of forest conditions and the response of the ecosystem to environmental factors. The study approach is based on a large number of permanent plots for extensive monitoring (Level 1. At this level, crown condition is assessed annually, and soil condition and the nutritional status of forests surveyed. Some of the permanent plots were selected for intensive monitoring (Level 2, focussing mainly on the impact of atmospheric pollution on forest ecosystems. Level 2 monitoring also includes increment analyses, ground vegetation assessment, atmospheric deposition, soil solution analyses and climatic observations. This paper summarises the main results of a pluriannual research, which provides a general picture of the state of forest health in the region and focuses on more detailed investigations, described as case studies. Modified wet and dry samplers which use a water surface to collect dry deposition were used in a pluriannual field campaign at five sites in alpine and prealpine areas, to measure the total atmospheric depositions and to evaluate the nitrogen and sulphate exceedances of critical loads. Throughfall and bulk precipitation chemistry were studied for five years (June 1994-May 1999 at two high elevation forest sites (Val Gerola and Val Masino which were known to differ in terms of tree health, as assessed by live crown condition. Results indicated a higher contribution from the dry deposition of N-NO3 -, N-NH4 + and H+ and considerable canopy leaching of Ca2+, K+ and weak organic acids at Val Gerola, where the symptoms of damage were more evident. In the area of Val Masino (SO, included since 1997 in the national CONECOFOR network, investigations focused on the effectiveness of the biological compartment in modifying fluxes of atmospheric elements, and on the role of nitrogen both as an

  18. Fabrication of transparent antifouling thin films with fractal structure by atmospheric pressure cold plasma deposition.

    Science.gov (United States)

    Miyagawa, Hayato; Yamauchi, Koji; Kim, Yoon-Kee; Ogawa, Kazufumi; Yamaguchi, Kenzo; Suzaki, Yoshifumi

    2012-12-21

    Antifouling surface with both superhydrophobicity and oil-repellency has been fabricated on glass substrate by forming fractal microstructure(s). The fractal microstructure was constituted by transparent silica particles of 100 nm diameter and transparent zinc-oxide columns grown on silica particles by atmospheric pressure cold plasma deposition. The sample surface was coated with a chemically adsorbed monomolecular layer. We found that one sample has the superhydrophobic ability with a water droplet contact angle of more than 150°, while another sample has a high transmittance of more than 85% in a wavelength range from 400 to 800 nm. PMID:23186100

  19. Reconstructing historical atmospheric mercury deposition in Western Europe using : Misten peat bog cores, Belgium

    OpenAIRE

    Allan, Mohammed; Le Roux, Gaël; Jeroen E Sonke; Piotrowska, Natalia; Streel, Maurice; Fagel, Nathalie

    2013-01-01

    Four sediment cores were collected in 2008 from the Misten ombrotrophic peat bog in the Northern part of the Hautes Fagnes Plateau in Belgium. Total mercury (Hg) concentrations were analyzed to investigate the intra-site variability in atmospheric Hg deposition over the past 1500 years. Mercury concentrations in the four cores ranged from 16 to 1100 μg kg− 1, with the maxima between 840 and 1100 μg kg− 1. A chronological framework was established using radiometric 210Pb and 14C dating of two ...

  20. Development of ion-exchange collectors for monitoring atmospheric deposition of inorganic pollutants in Alaska parklands

    Science.gov (United States)

    Brumbaugh, William G.; Arms, Jesse W.; Linder, Greg L.; Melton, Vanessa D.

    2016-09-19

    Between 2010 and 2014, the U.S. Geological Survey completed a series of laboratory and field experiments designed to develop methodology to support the National Park Service’s long-term atmospheric pollutant monitoring efforts in parklands of Arctic Alaska. The goals of this research were to develop passive sampling methods that could be used for long-term monitoring of inorganic pollutants in remote areas of arctic parklands and characterize relations between wet and dry deposition of atmospheric pollutants to that of concentrations accumulated by mosses, specifically the stair-step, splendid feather moss, Hylocomium splendens. Mosses and lichens have been used by National Park Service managers as atmospheric pollutant biomonitors since about 1990; however, additional research is needed to better characterize the dynamics of moss bioaccumulation for various classes of atmospheric pollutants. To meet these research goals, the U.S. Geological Survey investigated the use of passive ionexchange collectors (IECs) that were adapted from the design of Fenn and others (2004). Using a modified IEC configuration, mulitple experiments were completed that included the following: (a) preliminary laboratory and development testing of IECs, (b) pilot-scale validation field studies during 2012 with IECs at sites with instrumental monitoring stations, and (c) deployment of IECs in 2014 at sites in Alaska having known or suspected regional sources of atmospheric pollutants where samples of Hylocomium splendens moss also could be collected for comparison. The targeted substances primarily included ammonium, nitrate, and sulfate ions, and certain toxicologically important trace metals, including cadmium, cobalt, copper, nickel, lead, and zinc.Deposition of atmospheric pollutants is comparatively low throughout most of Alaska; consequently, modifications of the original IEC design were needed. The most notable modification was conversion from a single-stage mixed-bed column to a two

  1. Effects of atmospheric deposition of energy-related pollutants on water quality: a review and assessment

    International Nuclear Information System (INIS)

    The effects on surface-water quality of atmospheric pollutants that are generated during energy production are reviewed and evaluated. Atmospheric inputs from such sources to the aquatic environment may include trace elements, organic compounds, radionuclides, and acids. Combustion is the largest energy-related source of trace-element emissions to the atmosphere. This report reviews the nature of these emissions from coal-fired power plants and discusses their terrestrial and aquatic effects following deposition. Several simple models for lakes and streams are developed and are applied to assess the potential for adverse effects on surface-water quality of trace-element emissions from coal combustion. The probability of acute impacts on the aquatic environment appears to be low; however, more subtle, chronic effects are possible. The character of acid precipitation is reviewed, with emphasis on aquatic effects, and the nature of existing or potential effects on water quality, aquatic biota, and water supply is considered. The response of the aquatic environment to acid precipitation depends on the type of soils and bedrock in a watershed and the chemical characteristics of the water bodies in question. Methods for identifying regions sensitive to acid inputs are reviewed. The observed impact of acid precipitation ranges from no effects to elimination of fish populations. Coal-fired power plants and various stages of the nuclear fuel cycle release radionuclides to the atmosphere. Radioactive releases to the atmosphere from these sources and the possible aquatic effects of such releases are examined. For the nuclear fuel cycle, the major releases are from reactors and reprocessing. Although aquatic effects of atmospheric releases have not been fully quantified, there seems little reason for concern for man or aquatic biota

  2. Effects of atmospheric deposition of energy-related pollutants on water quality: a review and assessment

    Energy Technology Data Exchange (ETDEWEB)

    Davis, M.J.

    1981-05-01

    The effects on surface-water quality of atmospheric pollutants that are generated during energy production are reviewed and evaluated. Atmospheric inputs from such sources to the aquatic environment may include trace elements, organic compounds, radionuclides, and acids. Combustion is the largest energy-related source of trace-element emissions to the atmosphere. This report reviews the nature of these emissions from coal-fired power plants and discusses their terrestrial and aquatic effects following deposition. Several simple models for lakes and streams are developed and are applied to assess the potential for adverse effects on surface-water quality of trace-element emissions from coal combustion. The probability of acute impacts on the aquatic environment appears to be low; however, more subtle, chronic effects are possible. The character of acid precipitation is reviewed, with emphasis on aquatic effects, and the nature of existing or potential effects on water quality, aquatic biota, and water supply is considered. The response of the aquatic environment to acid precipitation depends on the type of soils and bedrock in a watershed and the chemical characteristics of the water bodies in question. Methods for identifying regions sensitive to acid inputs are reviewed. The observed impact of acid precipitation ranges from no effects to elimination of fish populations. Coal-fired power plants and various stages of the nuclear fuel cycle release radionuclides to the atmosphere. Radioactive releases to the atmosphere from these sources and the possible aquatic effects of such releases are examined. For the nuclear fuel cycle, the major releases are from reactors and reprocessing. Although aquatic effects of atmospheric releases have not been fully quantified, there seems little reason for concern for man or aquatic biota.

  3. U.S. Geological Survey external quality-assurance project report to the National Atmospheric Deposition Program / National Trends Network and Mercury Deposition Network, 2007-08

    Science.gov (United States)

    Wetherbee, Gregory A.; Latysh, Natalie E.; Chesney, Tanya A.

    2010-01-01

    The U.S. Geological Survey (USGS) used six distinct programs to provide external quality-assurance monitoring for the National Atmospheric Deposition Program / National Trends Network (NTN) and Mercury Deposition Network (MDN) during 2007-08. The field-audit program assessed the effects of onsite exposure, sample handling, and shipping on the chemistry of NTN samples, and a system-blank program assessed the same effects for MDN. Two interlaboratory-comparison programs assessed the bias and variability of the chemical analysis data from the Central Analytical Laboratory (CAL), Mercury (Hg) Analytical Laboratory (HAL), and 12 other participating laboratories. A blind-audit program was also implemented for the MDN to evaluate analytical bias in HAL total Hg concentration data. A co-located-sampler program was used to identify and quantify potential shifts in NADP data resulting from replacement of original network instrumentation with new electronic recording rain gages (E-gages) and prototype precipitation collectors. The results indicate that NADP data continue to be of sufficient quality for the analysis of spatial distributions and time trends of chemical constituents in wet deposition across the U.S. NADP data-quality objectives continued to be achieved during 2007-08. Results also indicate that retrofit of the NADP networks with the new E-gages is not likely to create step-function type shifts in NADP precipitation-depth records, except for sites where annual precipitation depth is dominated by snow because the E-gages tend to catch more snow than the original NADP rain gages. Evaluation of prototype precipitation collectors revealed no difference in sample volumes and analyte concentrations between the original NADP collectors and modified, deep-bucket collectors, but the Yankee Environmental Systems, Inc. (YES) collector obtained samples of significantly higher volumes and analyte concentrations than the standard NADP collector.

  4. Atmospheric aerosol in an urban area: Comparison of measurement instruments and methodologies and pulmonary deposition assessment

    International Nuclear Information System (INIS)

    In March 1995 a measurement campaign of atmospheric aerosol in the Bologna urban area (Italy) was carried out. A transportable laboratory, set up by ENEA (Italian national Agency for New Technologies, Energy and the Environment) Environmental Department (Bologna), was utilized with instruments for measurement of atmospheric aerosol and meteorological parameters. The aim of this campaign was of dual purpose: to characterize aerosol in urban area and to compare different instruments and methodologies of measurements. Mass concentrations measurements, evaluated on a 23-hour period with total filter, PM10 dichotomous sampler and low pressure impactor (LPI Berner), have provided information respectively about total suspended particles, respirable fraction and granulometric parameters of aerosol. Eight meteorologic parameters, number concentration of submicromic fraction of aerosol and mass concentration of micromic fraction have been continually measured. Then, in a daytime period, several number granulometries of atmospheric aerosol have also been estimated by means of diffusion battery system. Results related to different measurement methodologies and granulometric characteristics of aerosol are presented here. Pulmonary deposition of atmospheric aerosol is finally calculated, using granulometries provided by LPI Brener and ICRP 66 human respiratory tract model

  5. Nitrogen budget of Lago Maggiore: the relative importance of atmospheric deposition and catchment sources

    Directory of Open Access Journals (Sweden)

    Gabriele TARTARI

    2001-02-01

    Full Text Available Hydrological and chemical data of 1996 and 1997 are used to evaluate the relative contributions of atmospheric deposition and urban/industrial wastewaters to the nitrogen budget of Lago Maggiore. The atmospheric load of nitrogen was about 80% of the total input to the lake, with negligible variations in dry (1997 and wet (1996 years. A comparison of the two study years with the yearly N budgets evaluated from 1978 to 1998, showed that the N load was higher with increasing amounts of precipitation/water inflow. Soils and vegetation act as N sinks; the % retention varies between 40-60% for the forested catchments with low population density in the central-northern part of the basin, to values close to zero or even negative in the south, indicating a net leaching from the soils. The Traaen & Stoddard (1995 approach revealed that all the catchments of the major inflowing rivers were oversaturated with nitrogen. The long-term trend of nitrogen concentrations in Lago Maggiore (1955-99 is analogous to the trend for atmospheric deposition (1975-99, which is related to emissions of nitrogen oxides and ammonia in the atmosphere. The relationships between the present N load and in-lake concentrations are discussed using a budget model, which is also used to infer the pristine load of N. The close relationships between N trends in lakes Maggiore, Como and Iseo, and the geographical and anthropogenic features common to their catchments, suggest that the results obtained for Lago Maggiore can be extended to a wider area.

  6. An evaluation of atmospheric deposition of trace elements into the Great Lakes.

    Science.gov (United States)

    Biegalski, S; Landsberger, S

    1999-01-01

    High-volume air samplers were used to collect aerosol samples on Whatman 41 air filters at the Canadian air sampling stations Burnt Island, Egbert, and Point Petre. Once collected, the samples were analyzed for trace elements by neutron activation analysis. Air concentrations of over 30 trace elements were determined. A special focus was made to utilize Compton suppression gamma-ray spectroscopy and epithermal irradiations to enhance the detection limits of neutron activation analysis. These techniques allowed for the determination of trace elements at very low levels. Results of the study of the trace-metal dry deposition into Lakes Huron and Ontario indicated that the majority of the total deposition resulted from crustal materials. However, dry deposition is also a significant pathway for many toxic anthropogenic trace metals into the Great Lakes. PMID:10676498

  7. Photocatalytic Functional Coating of TiO2 Thin Film Deposited by Cyclic Plasma Chemical Vapor Deposition at Atmospheric Pressure

    Science.gov (United States)

    Kwon, Jung-Dae; Rha, Jong-Joo; Nam, Kee-Seok; Park, Jin-Seong

    2011-08-01

    Photocatalytic TiO2 thin films were prepared with titanium tetraisopropoxide (TTIP) using cyclic plasma chemical vapor deposition (CPCVD) at atmospheric pressure. The CPCVD TiO2 films contain carbon-free impurities up to 100 °C and polycrystalline anatase phases up to 200 °C, due to the radicals and ion-bombardments. The CPCVD TiO2 films have high transparency in the visible wavelength region and absorb wavelengths below 400 nm (>3.2 eV). The photocatalytic effects of the CPCVD TiO2 and commercial sprayed TiO2 films were measured by decomposing methylene blue (MB) solution under UV irradiation. The smooth CPCVD TiO2 films showed a relatively lower photocatalytic efficiency, but superior catalyst-recycling efficiency, due to their high adhesion strength on the substrates. This CPCVD technique may provide the means to produce photocatalytic thin films with low cost and high efficiency, which would be a reasonable candidate for practical photocatalytic applications, because of the reliability and stability of their photocatalytic efficiency in a practical environment.

  8. Conductive zinc oxide thin film coatings by combustion chemical vapour deposition at atmospheric pressure

    International Nuclear Information System (INIS)

    We have established a combustion chemical vapour deposition (C-CVD) system for the deposition of zinc oxide (ZnO) at atmospheric pressure. This C-CVD process has the advantage of a short exposure of the substrates to the flame. It is also potentially applicable as an inline coating system. Fundamental studies were performed on undoped ZnO. The specific resistivity of these layers strongly depends on the film thickness and decreases with increasing thickness. As the lowest resistivities, values of about 2.0 · 10−1 Ωcm are achieved. Ultra-violet photoemission spectra show the valence band structure of the deposited ZnO. The work function and valence band edge were determined. UV–vis spectra were taken to investigate the transmission of the coated glass samples. From these spectra the band gap energy was obtained. Raman spectroscopy as well as infrared spectroscopy confirmed the presence of ordered ZnO crystallites. The X-ray diffraction verified this result and illustrates the hexagonal structure. In the mid-infrared range precursor deposits were detected for low substrate temperatures. - Highlights: ► Zinc oxide (ZnO) films are conductive in the range of 2.0 · 10−1 Ωcm. ► X-ray diffraction, Raman and infrared spectroscopy indicate crystalline ZnO films. ► Precursor deposits were proved within the films for low growing temperatures. ► Band gap energy changes are achieved due to different growing temperatures

  9. Nitrogen-rich plasma polymers: Comparison of films deposited in atmospheric- and low-pressure plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Truica-Marasescu, Florina [Groupe des Couches Minces (GCM) and Department of Engineering Physics, Ecole Polytechnique, C.P. 6079, Succ. Centre-Ville, Montreal, QC H3C 3A7 (Canada)], E-mail: florina-elena.truica-marasescu@polymtl.ca; Girard-Lauriault, Pierre-Luc; Lippitz, Andreas; Unger, Wolfgang E.S. [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Unter den Eichen 44-46, D-12203 Berlin (Germany); Wertheimer, Michael R. [Groupe des Couches Minces (GCM) and Department of Engineering Physics, Ecole Polytechnique, C.P. 6079, Succ. Centre-Ville, Montreal, QC H3C 3A7 (Canada)

    2008-09-01

    Low- and atmospheric-pressure plasma co-polymerisations of binary gas mixtures of C{sub 2}H{sub 4} and NH{sub 3} or N{sub 2}, respectively, were investigated for depositing N-rich plasma polymer coatings for biomedical applications. Deposition kinetics and relevant surface characteristics of resulting plasma polymerised ethylene enriched with nitrogen, 'PPE:N', coatings were investigated as a function of the gas mixture ratio, X = NH{sub 3}(N{sub 2})/C{sub 2}H{sub 4}. Physico-chemical properties of the coatings were determined using a combination of complementary surface-sensitive techniques: for example, total nitrogen concentrations, [N], up to 40 at.% were measured by X-ray Photoelectron Spectroscopy, XPS, while those of primary amines, [-NH{sub 2}], were determined by performing chemical derivatisation followed by XPS analyses. PPE:N films were further characterised by UV-VIS Ellipsometry, Near Edge X-ray Absorption Fine Structure Spectroscopy, IR Spectroscopy and by Contact Angle Goniometry measurements. The stability of the coatings was tested, both in terms of water solubility and of 'ageing' in ambient atmosphere. For the latter, selected samples were stored in the laboratory for different durations, in order to assess possible changes in their chemical structures.

  10. Dietary intake of pollutant aerosols via vegetables influenced by atmospheric deposition and wastewater irrigation.

    Science.gov (United States)

    Pandey, Richa; Shubhashish, Kumar; Pandey, Jitendra

    2012-02-01

    Pot culture experiments were conducted to study dietary intake of heavy metals via vegetables, spinach (Spinacia oleracea L.), radish (Raphanus sativus L.) and tomato (Lycopersicon esculentum Mill) grown under the influence of atmospheric deposition and wastewater irrigation. The results indicated substantial accumulation of heavy metals in vegetables, which contribute significantly to dietary intake of total heavy metals ranging from 1.34 to 110.40 μg g⁻¹ through leaves (spinach), 1.04 to 105.86 μg g⁻¹ through root (radish) and 0.608 to 82.19 μg g⁻¹ through fruits (tomato). Concentration of Cd, Ni and Pb in vegetables exceeded the safe limits of Prevention of Food Adulteration Act 1954. Health risk index for Cd and Pb exceeded the safe limits set by the United States Environmental Protection Agency. The study indicated that the atmospheric depositions as well as wastewater irrigation have significantly elevated the levels of heavy metals in dietary vegetables presenting a significant threat for the health of users. PMID:22019253

  11. Atmospheric Pressure Spray Chemical Vapor Deposited CuInS2 Thin Films for Photovoltaic Applications

    Science.gov (United States)

    Harris, J. D.; Raffaelle, R. P.; Banger, K. K.; Smith, M. A.; Scheiman, D. A.; Hepp, A. F.

    2002-01-01

    Solar cells have been prepared using atmospheric pressure spray chemical vapor deposited CuInS2 absorbers. The CuInS2 films were deposited at 390 C using the single source precursor (PPh3)2CuIn(SEt)4 in an argon atmosphere. The absorber ranges in thickness from 0.75 - 1.0 micrometers, and exhibits a crystallographic gradient, with the leading edge having a (220) preferred orientation and the trailing edge having a (112) orientation. Schottky diodes prepared by thermal evaporation of aluminum contacts on to the CuInS2 yielded diodes for films that were annealed at 600 C. Solar cells were prepared using annealed films and had the (top down) composition of Al/ZnO/CdS/CuInS2/Mo/Glass. The Jsc, Voc, FF and (eta) were 6.46 mA per square centimeter, 307 mV, 24% and 0.35%, respectively for the best small area cells under simulated AM0 illumination.

  12. Atmospheric deposition of long-lived Beta radionuclides over the territory of Bulgaria during the last decades

    International Nuclear Information System (INIS)

    The sources of atmospheric radioactivity are discussed and compared. Radon isotopes and their daughters' dominate the natural background of beta activity in the surface air. The man-made radionuclides, much of them beta emitters, started to contaminate regionally and globally the environment after 1940's due to the atmospheric nuclear bomb tests. Additional significant sources of technogenic radionuclides in the atmosphere were nuclear accidents with pronounced examples of Chernobyl and Fukushima. The Bulgarian network for atmospheric radioactivity monitoring has been developing since 1959 in the frame of the state Hydro-meteorological service, now National Institute of Meteorology and Hydrology. It includes daily measurements of aerosol beta activity and deposition immediately and 120h after the sampling. The time and space variations of deposited beta activity, based on long term data records are presented and impact assessment of the different sources is given. The role of precipitation in deposition of radionuclides is evaluated. (author)

  13. Evaluation of OTT PLUVIO Precipitation Gage versus Belfort Universal Precipitation Gage 5-780 for the National Atmospheric Deposition Program

    Science.gov (United States)

    Tumbusch, Mary L.

    2003-01-01

    The National Atmospheric Deposition Program, a cooperative effort supported by Federal, State, and local agencies, and Indian Tribes, was established in 1977 to study atmospheric deposition and its impact on the environment. The program's National Trends Network now includes wet-deposition networks at more than 250 sites across the United States, Canada, Puerto Rico, and the Virgin Islands. Precipitation amounts are currently measured using a Belfort Universal Precipitation Gage 5-780, which involves technology that is more than 50 years old. In 1999, a three-phase study was begun to evaluate several weighing, all-weather precipitation gages to find a possible replacement for the Belfort Universal Precipitation Gage 5-780. One gage that performed consistently well in phase I and II testing was the OTT PLUVIO Precipitation Gage. Phase III of the study, discussed herein, was to determine the accuracy and comparability of the data sets collected by the OTT PLUVIO Precipitation Gages and the existing Belfort Universal Precipitation Gage 5-780. Seven OTT PLUVIO Precipitation Gages were installed at six National Trends Network sites across the country for a data-collection period of approximately 18 months. The NovaLynx Model 260-2510 Standard Rain and Snow Gage also was used, as a reference, at two of the sites. Paired t-tests analysis showed no significant differences in precipitation measurements between the Belfort Universal Precipitation Gage 5-780 and the OTT PLUVIO Precipitation Gages at three of the six sites. When the false positives were removed from the precipitation-event data sets, the gages at all sites were in agreement and the paired t-tests showed the gage measurements were not significantly different. A false positive is defined as a zero response from the Belfort Universal Precipitation Gage 5-780 concurrent with a recorded response from the OTT PLUVIO Precipitation Gage.

  14. Variability of atmospheric depositions of artificial radioelements and their transfer into soils

    International Nuclear Information System (INIS)

    In this Habilitation thesis, I present the results and prospects of the main research topics that contribute to bettering our knowledge of the behaviour of artificial radioelements in the geosphere and biosphere. In the first chapter I present a summary of the research carried out for my thesis on the Oklo reactors. In the subsequent chapters I present my research work at the IRSN. The second chapter concerns the atmospheric depositions of radioactive contaminants. I have studied the principal environmental parameters involved in the empirical modelling of the transfer of artificial radioelements from the atmosphere to the soil. Here I essentially use measurements of artificial radioelements (137Cs, plutonium, americium) in soils that reveal the variability of accidental depositions further to the Chernobyl disaster (paragraph 2.1) and chronic radioactive depositions coming from the atmospheric testing of nuclear weapons (paragraph 2.2). In the third chapter I address the problem of transfers of artificial radioelements into the soil. The interest of this lies in the fact that these transfers represent serious risks for man. Taken over the long term (in the months and years that follow the depositing of radioactive elements on the ground and plants), the transfers of radioactive pollutants into the soil are responsible for the contamination of both plants (transfer via the roots) and underground water and surface water (transfer after vertical migration). My research work into the transfers of radioactive pollutants in soils is centred on vertical migrations and root transfers, as both these processes can be studied through environmental samplings and measurements. More precisely, I have studied the migrations of radioactive pollutants and their geochemical analogues in different types of soils (paragraph 3.1) and the variability of the activities of radiostrontium and radiocesium in the compartments of permanent grassland zones (soil, grass, milk and cheese

  15. Atmospheric deposition and solute export in giant sequoia: mixed conifer watersheds in the Sierra Nevada, California

    Science.gov (United States)

    Stohlgren, Thomas J.; Melack, John M.; Esperanza, Anne M.; Parsons, David J.

    1991-01-01

    Atmospheric depostion and stream discharge and solutes were measured for three years (September 1984 - August 1987) in two mixed conifer watersheds in Sequoia National Park, in the southern Sierra Nevada of California. The Log Creek watershed (50 ha, 2067-2397 m elev.) is drained by a perennial stream, while Tharp's Creek watershed (13 ha, 2067-2255 m elev.) contains an intermittent stream. Dominant trees in the area include Abies concolor (white fir), Sequoiadendron giganteum (giant sequoia), A. magnifica (red fir), and Pinus lambertiana (sugar pine). Bedrock is predominantly granite and granodiorite, and the soils are mostly Pachic Xerumbrepts. Over the three year period, sulfate (SO42-), nitrate (NO3-), and chloride (Cl-) were the major anions in bulk precipitation with volume-weighted average concentrations of 12.6, 12.3 and 10.0 μeq/1, respectively. Annual inputs of NO3-N, NH4-N and SO4-S from wet deposition were about 60 to 75% of those reported from bulk deposition collectors. Discharge from the two watersheds occurs primarily during spring snowmelt. Solute exports from Log and Tharp's Creeks were dominated by HCO3-, Ca2+ and Na+, while H+, NO3-, NH4+ and PO43- outputs were relatively small. Solute concentrations were weakly correlated with instantaneous stream flow for all solutes (r2 3- (Log Cr. r2=0.72; Tharp's Cr. r2=0.38), Na+ (Log Cr. r2=0.56; Tharp's Cr. r2=0.47), and silicate (Log Cr. r2=0.71; Tharp's Cr. r2=0.49). Mean annual atmospheric contributions of NO3-N (1.6 kg ha-1), NH4-N (1.7 kg ha-1), and SO4-S (1.8 kg ha-1), which are associated with acidic deposition, greatly exceed hydrologic losses. Annual watershed yields (expressed as eq ha-1) of HCO3- exceeded by factors of 2.5 to 37 the annual atmospheric deposition of H+.

  16. Mercury in soils, lakes, and fish in Voyageurs National Park (Minnesota): Importance of atmospheric deposition and ecosystem factors

    Science.gov (United States)

    Wiener, J.G.; Knights, B.C.; Sandheinrich, M.B.; Jeremiason, J.D.; Brigham, M.E.; Engstrom, D.R.; Woodruff, L.G.; Cannon, W.F.; Balogh, S.J.

    2006-01-01

    Concentrations of methylmercury in game fish from many interior lakes in Voyageurs National Park (MN, U.S.A.) substantially exceed criteria for the protection of human health. We assessed the importance of atmospheric and geologic sources of mercury to interior lakes and watersheds within the Park and identified ecosystem factors associated with variation in methylmercury contamination of lacustrine food webs. Geologic sources of mercury were small, based on analyses of underlying bedrock and C-horizon soils, and nearly all mercury in the O- and A-horizon soils was derived from atmospheric deposition. Analyses of dated sediment cores from five lakes showed that most (63% ?? 13%) of the mercury accumulated in lake sediments during the 1900s was from anthropogenic sources. Contamination of food webs was assessed by analysis of whole, 1-year-old yellow perch (Perca flavescens), a regionally important prey fish. The concentrations of total mercury in yellow perch and of methylmercury in lake water varied substantially among lakes, reflecting the influence of ecosystem processes and variables that affect the microbial production and abundance of methylmercury. Models developed with the information-theoretic approach (Akaike Information Criteria) identified lake water pH, dissolved sulfate, and total organic carbon (an indicator of wetland influence) as factors influencing methylmercury concentrations in lake water and fish. We conclude that nearly all of the mercury in fish in this seemingly pristine landscape was derived from atmospheric deposition, that most of this bioaccumulated mercury was from anthropogenic sources, and that both watershed and lacustrine factors exert important controls on the bioaccumulation of methylmercury. ?? 2006 American Chemical Society.

  17. Polycyclic aromatic hydrocarbons (PAHs) in the Mediterranean Sea: Atmospheric occurrence, deposition and decoupling with settling fluxes in the water column

    International Nuclear Information System (INIS)

    ∑30PAH gas phase concentrations (13–86 and 22–40 ng m−3 in the Mediterranean and Black Seas, respectively) dominated the atmospheric levels due to the high contribution of phenanthrene, dibenzothiophene and their alkylated derivates. The high variability of PAH atmospheric concentrations in the different sub-basins is due to several factors (i.e. air-mass trajectory, proximity to sources and losses by deposition). The ∑30PAH atmospheric deposition (dominated by low MW PAH net air–water diffusive fluxes) is estimated to be ∼3100 ton y−1 (Mediterranean) and ∼500 ton y−1 (Black Sea). Net volatilization for certain PAHs was estimated. Deposition fluxes (1–2 orders of magnitude higher than reported PAH settling fluxes in the water column) confirm an important depletion/sink of water column PAH in the photic zone, especially for low MW PAHs. Degradation processes in the water column may be responsible for this decoupling. Conversely, high MW PAHs dry deposition fluxes are similar to their settling fluxes. Highlights: ► First comprehensive assessment of atmospheric PAH levels and deposition across the Mediterranean Sea. ► PAH atmospheric concentrations are highly variable across the Mediterranean Sea. ► Mediterranean Sea open waters receive ∼3100 ton of PAHs each year from the atmosphere. ► Important depletion of low MW PAH water column concentrations in the photic zone. ► Degradation processes most likely responsible of the atmospheric deposition – settling fluxes decoupling. - Capsule: Mediterranean Sea open waters receive ∼3100 ton of PAHs each year from the atmosphere but only a small fraction of this input settle down in the water column due to degradation processes.

  18. An Evaluation of Atmospheric-pressure Plasma for the Cost-Effective Deposition of Antireflection Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Rob Sailer; Guruvenket Srinivasan; Kyle W. Johnson; Douglas L. Schulz

    2010-04-01

    Atmospheric-pressure plasma deposition (APPD) has previously been used to deposit various functional materials including polymeric surface modification layers, transparent conducting oxides, and photo catalytic materials. For many plasma polymerized coatings, reaction occurs via free radical mechanism where the high energy electrons from the plasma activate the olefinic carbon-carbon double bonds - a typical functional group in such precursors. The precursors for such systems are typically inexpensive and readily available and have been used in vacuum PECVD previously. The objectives are to investigate: (1) the effect of plasma power, gas composition and substrate temperature on the Si-based film properties using triethylsilane(TES) as the precursor; and (2) the chemical, mechanical, and optical properties of several experimental matrices based on Design of Experiment (DOE) principals. A simple APPD route has been utilized to deposit Si based films from an inexpensive precursor - Triethylsilane (TES). Preliminary results indicates formation of Si-C & Si-O and Si-O, Si-C & Si-N bonds with oxygen and nitrogen plasmas respectively. N{sub 2}-O{sub 2} plasma showed mixed trend; however oxygen remains a significant portion of all films, despite attempts to minimize exposure to atmosphere. SiN, SiC, and SiO ratios can be modified by the reaction conditions resulting in differing film properties. SE studies revealed that films with SiN bond possess refractive index higher than coatings with Si-O/Si-C bonds. Variable angle reflectance studies showed that SiOCN coatings offer AR properties; however thickness and refractive index optimization of these coatings remains necessary for application as potential AR coatings.

  19. Atmospheric background trace elements deposition in Tierra del Fuego region (Patagonia, Argentina), using transplanted Usnea barbata lichens.

    Science.gov (United States)

    Conti, Marcelo Enrique; Finoia, Maria Grazia; Bocca, Beatrice; Mele, Giustino; Alimonti, Alessandro; Pino, Anna

    2012-01-01

    Lichen, Usnea barbata, transplants taken from Tierra del Fuego (south Patagonia, Argentina) were tested as potential biomonitors of atmospheric airborne deposition in an apparently pristine environment. In 2005, lichens were sampled in a reference site (n = 31) and transplanted in the northern Region of Tierra del Fuego. After, respectively, 1 month and 1 year of exposure, we collected them. The aim of the study was to determine the bioaccumulation of 26 elements in order to evaluate the background levels in the selected area. Samples were analyzed by the sector field inductively coupled plasma mass spectrometry. Discriminant analysis on principal component analysis factors was applied in order to explore the relationship among the different elements as far as time and spatial variation in transplants regards. The analysis was tested by Monte Carlo test based on 999 replicates. The most important contamination source resulted to be the atmospheric soil particle deposition. Furthermore, the results were compared with those obtained from the lichens collected in central and southern Tierra del Fuego. This study confirms the ability of U. barbata to reflect the background levels of the 26 elements in that environment. Compared with other background sites in the world, we did confirm that Tierra del Fuego lichens have a low content of the studied elements. Tierra del Fuego turned out not to be a pristine environment as supposed, but it can be considered as a reference basal ecosystem for useful comparisons among different geographical areas. These findings can be very relevant and useful for environmental conservation programs. PMID:21409357

  20. The effects of atmospheric nitrogen deposition in the Rocky Mountains of Colorado and southern Wyoming, USA-a critical review

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Douglas A

    2004-01-01

    The Rocky Mountains of Colorado and southern Wyoming receive atmospheric nitrogen (N) deposition that ranges from 2 to 7 kg ha{sup -1} yr{sup -1}, and some previous research indicates pronounced ecosystem effects at the highest rates of deposition. This paper provides a critical review of previously published studies on the effects of atmospheric N deposition in the region. Plant community changes have been demonstrated through N fertilization studies, however, N limitation is still widely reported in alpine tundra and subalpine forests of the Front Range, and sensitivity to changes in snow cover alone indicate the importance of climate sensitivity in these ecosystems. Retention of N in atmospheric wet deposition is <50% in some watersheds east of the Continental Divide, which reflects low biomass and a short growing season relative to the timing and N load in deposition. Regional upward temporal trends in surface water NO{sub 3}{sup -} concentrations have not been demonstrated, and future trend analyses must consider the role of climate as well as N deposition. Relatively high rates of atmospheric N deposition east of the Divide may have altered nutrient limitation of phytoplankton, species composition of diatoms, and amphibian populations, but most of these effects have been inconclusive to date, and additional studies are needed to confirm hypothesized cause and effect relations. Projected future population growth and energy use in Colorado and the west increase the likelihood that the subtle effects of atmospheric N deposition now evident in the Front Range will become more pronounced and widespread in the future. - The effects of nitrogen deposition will become more evident as growth increases.

  1. Diamond synthesis at atmospheric pressure by microwave capillary plasma chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hemawan, Kadek W.; Gou, Huiyang; Hemley, Russell J. [Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Rd., NW, Washington, DC 20015 (United States)

    2015-11-02

    Polycrystalline diamond has been synthesized on silicon substrates at atmospheric pressure, using a microwave capillary plasma chemical vapor deposition technique. The CH{sub 4}/Ar plasma was generated inside of quartz capillary tubes using 2.45 GHz microwave excitation without adding H{sub 2} into the deposition gas chemistry. Electronically excited species of CN, C{sub 2}, Ar, N{sub 2}, CH, H{sub β}, and H{sub α} were observed in the emission spectra. Raman measurements of deposited material indicate the formation of well-crystallized diamond, as evidenced by the sharp T{sub 2g} phonon at 1333 cm{sup −1} peak relative to the Raman features of graphitic carbon. Field emission scanning electron microscopy images reveal that, depending on the growth conditions, the carbon microstructures of grown films exhibit “coral” and “cauliflower-like” morphologies or well-facetted diamond crystals with grain sizes ranging from 100 nm to 10 μm.

  2. Modeling chemical vapor deposition of silicon dioxide in microreactors at atmospheric pressure

    International Nuclear Information System (INIS)

    We developed a multiphysics mathematical model for simulation of silicon dioxide Chemical Vapor Deposition (CVD) from tetraethyl orthosilicate (TEOS) and oxygen mixture in a microreactor at atmospheric pressure. Microfluidics is a promising technology with numerous applications in chemical synthesis due to its high heat and mass transfer efficiency and well-controlled flow parameters. Experimental studies of CVD microreactor technology are slow and expensive. Analytical solution of the governing equations is impossible due to the complexity of intertwined non-linear physical and chemical processes. Computer simulation is the most effective tool for design and optimization of microreactors. Our computational fluid dynamics model employs mass, momentum and energy balance equations for a laminar transient flow of a chemically reacting gas mixture at low Reynolds number. Simulation results show the influence of microreactor configuration and process parameters on SiO2 deposition rate and uniformity. We simulated three microreactors with the central channel diameter of 5, 10, 20 micrometers, varying gas flow rate in the range of 5-100 microliters per hour and temperature in the range of 300-800 °C. For each microchannel diameter we found an optimal set of process parameters providing the best quality of deposited material. The model will be used for optimization of the microreactor configuration and technological parameters to facilitate the experimental stage of this research

  3. Remote plasma-enhanced chemical vapour deposition of silicon nitride at atmospheric pressure

    International Nuclear Information System (INIS)

    Silicon nitride films were deposited using an atmospheric pressure plasma source. The discharge was produced by flowing nitrogen and helium through two perforated metal electrodes that were driven by 13.56 MHz radio frequency power. Deposition occurred by mixing the plasma effluent with silane and directing the flow onto a rotating silicon wafer heated to between 100 deg. C and 500 deg. C. Film growth rates ranged from 90±10 to 1300±130 A min-1. Varying the N2/SiH4 feed ratio from 55.0 to 5.5 caused the film stoichiometry to shift from SiN1.45 to SiN1.2. Minimum impurity concentrations of 0.04% carbon, 3.6% oxygen and 13.6% hydrogen were achieved at 500 deg. C, and an N2/SiH4 feed ratio of 22.0. The growth rate increased with increasing silane and nitrogen partial pressures, but was invariant with respect to substrate temperature and rotational speed. The deposition rate also decreased sharply with distance from the plasma. These results combined with emission spectra taken of the afterglow suggest that gas-phase reactions between nitrogen atoms and silane play an important role in this process

  4. Atmospheric pressure chemical vapor deposition of titanium dioxide films from TiCl4

    International Nuclear Information System (INIS)

    We report a low temperature atmospheric pressure chemical vapor deposition technique to deposit titanium oxide films on silicon wafers. The growth is achieved by using TiCl·H2O2 and O2 at temperatures ranging from 140 to 280 deg. C. Addition of H2O2 yields a significant reduction in the surface roughness with an enhanced deposition rate at temperatures as low as 170 deg. C. Growth at temperatures below 140 deg. C results in insignificant growth whereas at high temperatures a hazy and three-dimensional growth is observed. Using this technique a growth rate as high as 0.5 μm/h can be obtained with little roughness on the surface of the substrate. XRD, SEM, and FTIR analyses have been exploited to study the physical behavior of the layers. The electrical characterization of the films reveals a relative permittivity (εr) of 19-21 for the samples prepared with H2O2. A breakdown field of 1x107 V/cm is also obtained

  5. Climate, not atmospheric deposition, drives the biogeochemical mass-balance of a mountain watershed

    Science.gov (United States)

    Baron, Jill S.; Heath, Jared

    2014-01-01

    Watershed mass-balance methods are valuable tools for demonstrating impacts to water quality from atmospheric deposition and chemical weathering. Owen Bricker, a pioneer of the mass-balance method, began applying mass-balance modeling to small watersheds in the late 1960s and dedicated his career to expanding the literature and knowledge of complex watershed processes. We evaluated long-term trends in surface-water chemistry in the Loch Vale watershed, a 660-ha. alpine/subalpine catchment located in Rocky Mountain National Park, CO, USA. Many changes in surface-water chemistry correlated with multiple drivers, including summer or monthly temperature, snow water equivalent, and the runoff-to-precipitation ratio. Atmospheric deposition was not a significant causal agent for surface-water chemistry trends. We observed statistically significant increases in both concentrations and fluxes of weathering products including cations, SiO2, SO4 2−, and ANC, and in inorganic N, with inorganic N being primarily of atmospheric origin. These changes are evident in the individual months June, July, and August, and also in the combined June, July, and August summer season. Increasingly warm summer temperatures are melting what was once permanent ice and this may release elements entrained in the ice, stimulate chemical weathering with enhanced moisture availability, and stimulate microbial nitrification. Weathering rates may also be enhanced by sustained water availability in high snowpack years. Rapid change in the flux of weathering products and inorganic N is the direct and indirect result of a changing climate from warming temperatures and thawing cryosphere.

  6. Atmospheric Dispersion Analysis using MACCS2

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, R; Yang, J M

    2004-02-02

    The Nuclear Regulatory Commission (NRC) Regulatory Guide 1.145 requires an evaluation of the offsite atmospheric dispersion coefficient, {Chi}/Q, as a part of the acceptance criteria in the accident analysis. In it, it requires in sequence computations of (1) the overall site 95th percentile {Chi}/Q, (2) the maximum of the sixteen sector 99.5th percentile {Chi}/Q, and (3) comparison and selection of the worst of the two values for reporting in the safety analysis report (SAR). In all cases, the site-specific meteorology and sector-specific site boundary distances are employed in the evaluation. There are sixteen 22.5-sectors, the nearest site boundary of which is determined within the 45-arc centered on each of the sixteen compass directions.

  7. Observations of atmospheric Hg species and depositions in remote areas of China

    Directory of Open Access Journals (Sweden)

    Feng X.

    2013-04-01

    Full Text Available From September 2007, we conducted continuous measurements of speciated atmospheric mercury (Hg and atmospheric mercury depositions at five remote sites in China. Four of these sites were involved in the Global Mercury Observation System (GMOS as ground-based stations. These stations were located in the northwest, southwest, northeast, and east part of China, respectively, which represent the regional atmospheric Hg budgets in different areas of China. The preliminary results showed that mean TGM concentrations were in the range of 1.60 – 2.88 ng m-3, with relatively higher levels observed at sites in Eastern China and Southwestern China and lower levels at sites in Northeastern and Northwestern China. TGM concentrations at remote sites of China were also higher than those reported from background sites in North America and Europe, and this is corresponding very well with the Chinese great anthropogenic Hg emissions. Gaseous oxidized mercury (GOM and particulate bounded mercury (PBM were in the ranges of 3.2 – 7.4 pg m−3 and 19.4 – 43.5 pg m-3, respectively. The preliminary result on precipitation showed mean precipitation THg concentrations were in the range of 2.7 – 18.0 ng L-1.

  8. Chemical cycling and deposition of atmospheric mercury in polar regions: review of recent measurements and comparison with models

    Science.gov (United States)

    Angot, Hélène; Dastoor, Ashu; De Simone, Francesco; Gårdfeldt, Katarina; Gencarelli, Christian N.; Hedgecock, Ian M.; Langer, Sarka; Magand, Olivier; Mastromonaco, Michelle N.; Nordstrøm, Claus; Pfaffhuber, Katrine A.; Pirrone, Nicola; Ryjkov, Andrei; Selin, Noelle E.; Skov, Henrik; Song, Shaojie; Sprovieri, Francesca; Steffen, Alexandra; Toyota, Kenjiro; Travnikov, Oleg; Yang, Xin; Dommergue, Aurélien

    2016-08-01

    Mercury (Hg) is a worldwide contaminant that can cause adverse health effects to wildlife and humans. While atmospheric modeling traces the link from emissions to deposition of Hg onto environmental surfaces, large uncertainties arise from our incomplete understanding of atmospheric processes (oxidation pathways, deposition, and re-emission). Atmospheric Hg reactivity is exacerbated in high latitudes and there is still much to be learned from polar regions in terms of atmospheric processes. This paper provides a synthesis of the atmospheric Hg monitoring data available in recent years (2011-2015) in the Arctic and in Antarctica along with a comparison of these observations with numerical simulations using four cutting-edge global models. The cycle of atmospheric Hg in the Arctic and in Antarctica presents both similarities and differences. Coastal sites in the two regions are both influenced by springtime atmospheric Hg depletion events and by summertime snowpack re-emission and oceanic evasion of Hg. The cycle of atmospheric Hg differs between the two regions primarily because of their different geography. While Arctic sites are significantly influenced by northern hemispheric Hg emissions especially in winter, coastal Antarctic sites are significantly influenced by the reactivity observed on the East Antarctic ice sheet due to katabatic winds. Based on the comparison of multi-model simulations with observations, this paper discusses whether the processes that affect atmospheric Hg seasonality and interannual variability are appropriately represented in the models and identifies research gaps in our understanding of the atmospheric Hg cycling in high latitudes.

  9. Multi-model Mean Nitrogen and Sulfur Deposition from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP): Evaluation Historical and Projected Changes

    Science.gov (United States)

    Lamarque, J.-F.; Dentener, F.; McConnell, J.; Ro, C.-U.; Shaw, M.; Vet, R.; Bergmann, D.; Cameron-Smith, P.; Doherty, R.; Faluvegi, G.; Ghan, S. J.; Josse, B.; Lee, Y. H.; MacKenzie, I. A.; Plummer, D.; Shindell, D. T.; Stevenson, D. S.; Strode, S.; Zeng, G.

    2013-01-01

    We present multi-model global datasets of nitrogen and sulfate deposition covering time periods from 1850 to 2100, calculated within the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The computed deposition fluxes are compared to surface wet deposition and ice-core measurements. We use a new dataset of wet deposition for 2000-2002 based on critical assessment of the quality of existing regional network data. We show that for present-day (year 2000 ACCMIP time-slice), the ACCMIP results perform similarly to previously published multi-model assessments. For this time slice, we find a multi-model mean deposition of 50 Tg(N) yr1 from nitrogen oxide emissions, 60 Tg(N) yr1 from ammonia emissions, and 83 Tg(S) yr1 from sulfur emissions. The analysis of changes between 1980 and 2000 indicates significant differences between model and measurements over the United States but less so over Europe. This difference points towards misrepresentation of 1980 NH3 emissions over North America. Based on ice-core records, the 1850 deposition fluxes agree well with Greenland ice cores but the change between 1850 and 2000 seems to be overestimated in the Northern Hemisphere for both nitrogen and sulfur species. Using the Representative Concentration Pathways to define the projected climate and atmospheric chemistry related emissions and concentrations, we find large regional nitrogen deposition increases in 2100 in Latin America, Africa and parts of Asia under some of the scenarios considered. Increases in South Asia are especially large, and are seen in all scenarios, with 2100 values more than double 2000 in some scenarios and reaching 1300 mg(N) m2 yr1 averaged over regional to continental scale regions in RCP 2.6 and 8.5, 3050 larger than the values in any region currently (2000). The new ACCMIP deposition dataset provides novel, consistent and evaluated global gridded deposition fields for use in a wide range of climate and ecological studies.

  10. Spatio-temporal variations and influencing factors of polycyclic aromatic hydrocarbons in atmospheric bulk deposition along a plain-mountain transect in western China

    Science.gov (United States)

    Xing, Xinli; Zhang, Yuan; Yang, Dan; Zhang, Jiaquan; Chen, Wei; Wu, Chenxi; Liu, Hongxia; Qi, Shihua

    2016-08-01

    Ten atmospheric bulk deposition (the sum of wet and dry deposition) samplers for polycyclic aromatic hydrocarbons (PAHs) were deployed at a plain-mountain transect (namely PMT transect, from Daying to Qingping) in Chengdu Plain, West China from June 2007 to June 2008 in four consecutive seasons (about every three months). The bulk deposition fluxes of ∑15-PAHs ranged from 169.19 μg m-2 yr-1 to 978.58 μg m-2 yr-1 with geometric mean of 354.22 μg m-2 yr-1. The most prevalent PAHs were 4-ring (39.65%) and 3-ring (35.56%) PAHs. The flux values were comparable to those in rural areas. Higher fluxes of total PAHs were observed in the middle of PMT transect (SL, YX and JY, which were more urbanized than other sites). The seasonal deposition fluxes in the sampling profile indicated seasonality of the contaminant source was an important factor in controlling deposition fluxes. PAHs bulk deposition was negatively correlated with meteorological parameters (temperature, wind speed, humidity, and precipitation). No significant correlations between soil concentrations and atmospheric deposition were found along this transect. PAHs in soil samples had combined sources of coal, wood and petroleum combustion, while a simple source of coal, wood and grass combustion for bulk deposition. There were significant positive correlation relationship (p Mountain cold trap effect existed in this transect where the altitude was higher than 1000 m. Long-range transport had an impact on the bulk deposition in summer. And this transect was a source to Tibetan only in summer. The forward trajectory analysis showed most air masses did not undergo long-range transport due to the blocking effect of surrounding mountains. Only a few air masses (<10%) arrived at the eastern and northern region of China or farther regions via long-range transport.

  11. Atmospheric deposition of polybromodiphenyl ethers in remote mountain regions of Europe

    Directory of Open Access Journals (Sweden)

    L. Arellano

    2013-08-01

    Full Text Available Polybromodiphenyl ethers (PBDEs were analyzed in bulk atmospheric deposition collected in four European remote mountain areas over a period of two years (2004–2006: Lake Redon (Pyrenees, Gossenköllesee (Alps, Lochnagar (Grampian Mountains and Skalnate (Tatras. In all sites, the PBDE distributions were dominated by BDE209. BDE47 and BDE99 were the major low-brominated congeners, followed by BDE100 and BDE183. This composition is consistent with predominant inputs from the commercial mixtures decaBDE and pentaBDE. The total congener site-averaged fluxes ranged between 100 ng m−2 mo−1 (Alps and 190 ng m−2 mo−1 (Tatras. Significant correlations between PBDE deposition and percent of North Atlantic backwards air mass trajectories in the collected samples of the westernmost sites, Lochnagar and Redon, suggested an impact of transcontinental transfer of these pollutants from North American sources into Europe. Skalnate and, to a lower extent Redon, recorded another main PBDE source from central Europe corresponding to secondary emissions of the penta BDE commercial mixture. The fluxes of these secondary emissions were temperature dependent and correlated to total particle deposition and rainfall. Higher PBDE fluxes were observed at increasing temperature, particle deposition and precipitation. Another specific PBDE source was observed in United Kingdom and recorded in Lochnagar. Photolytic degradation during transport decreased the relative abundance of BDE209 and modified the emitted pentaBDE technical mixtures by depletion of the relative composition of BDE99 and, to a lower extent, BDE47. The transformations were more intense in the sites located above 2000 m, Redon and Gossenköllesee, and, particularly, during the warm periods.

  12. Atmospheric deposition of heavy metals in Norway. Nationwide survey 2010.; Atmosfareisk nedfall av tungmetaller i Norge. Landsomfattende undersoekelse i 2010,

    Energy Technology Data Exchange (ETDEWEB)

    Steinnes, Eiliv; Berg, Torunn; Uggerud, Hilde Thelle; Pfaffhuber, Katrine Aspmo

    2011-07-01

    The geographical distribution of atmospheric deposition of heavy metals in Norway was mapped in 2010 by analysis of moss samples from 464 sites all over the country. This report provides a presentation of the results and a comparison with data from a series of corresponding moss surveys starting 1977. The survey is part of an international program comprising large parts of Europe. The survey primarily concerns the ten metals of priority in the European program: vanadium, chromium, iron, nickel, copper, zinc, arsenic, cadmium, mercury, and lead. In addition data are reported for another 42 elements in the moss. The discussion of the obtained data mainly refers to contributions from air pollution. In addition influence from natural processes to the elemental composition of the moss and how it may influence the interpretation of the data is discussed. (Author)

  13. INFLUENCE OF NaC1 DEPOSITION ON ATMOSPHERIC CORROSION OF A3 STEEL IN THE PRESENCE OF SO2

    Institute of Scientific and Technical Information of China (English)

    Q. Qu; C.W. Yan; L. Zhang; Y. Wan; C.N. Cao

    2002-01-01

    The regularities of atmospheric corrosion of A3 steel deposited with different amountof NaCl exposed to the air containing 1ppm SO2 at 80% RH and 25℃ were studied inlaboratory. NaCl can accelerate the corrosion of A3 steel obviously under such con-dition. The relationship between the weight loss of A3 steel and the amount of NaCldeposition can be well described by using a quadratic function. Fourier transform in-frared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopyand electron dispersion X-ray analysis (SEM/EDAX) were used to characterize thecorrosion products. In the absence of NaCl, FeSO4 xH2O is the dominant corro-sion products, while Fe3O4, FeSO4@ H2O, β-FeOOH and γ-FeOOH dominate in thepresence of NaCl.

  14. Estimation of the contribution of ultrafine particles to lung deposition of particle-bound mutagens in the atmosphere.

    Science.gov (United States)

    Kawanaka, Youhei; Matsumoto, Emiko; Sakamoto, Kazuhiko; Yun, Sun-Ja

    2011-02-15

    The present study was performed to estimate the contributions of fine and ultrafine particles to the lung deposition of particle-bound mutagens in the atmosphere. This is the first estimation of the respiratory deposition of atmospheric particle-bound mutagens. Direct and S9-mediated mutagenicity of size-fractionated particulate matter (PM) collected at roadside and suburban sites was determined by the Ames test using Salmonella typhimurium strain TA98. Regional deposition efficiencies in the human respiratory tract of direct and S9-mediated mutagens in each size fraction were calculated using the LUDEP computer-based model. The model calculations showed that about 95% of the lung deposition of inhaled mutagens is caused by fine particles for both roadside and suburban atmospheres. Importantly, ultrafine particles were shown to contribute to the deposition of mutagens in the alveolar region of the lung by as much as 29% (+S9) and 26% (-S9) for the roadside atmosphere and 11% (+S9) and 13% (-S9) for the suburban atmosphere, although ultrafine particles contribute very little to the PM mass concentration. These results indicated that ultrafine particles play an important role as carriers of mutagens into the lung.

  15. Atmospheric gaseous elemental mercury (GEM concentrations and mercury depositions at a high-altitude mountain peak in south China

    Directory of Open Access Journals (Sweden)

    X. W. Fu

    2010-03-01

    Full Text Available China is regarded as the largest contributor of mercury (Hg to the global atmospheric Hg budget. However, concentration levels and depositions of atmospheric Hg in China are poorly known. Continuous measurements of atmospheric gaseous elemental mercury (GEM were carried out from May 2008 to May 2009 at the summit of Mt. Leigong in south China. Simultaneously, deposition fluxes of THg and MeHg in precipitation, throughfall and litterfall were also studied. Atmospheric GEM concentrations averaged 2.80±1.51 ng m−3, which was highly elevated compared to global background values but much lower than semi-rural and industrial/urban areas in China. Sources identification indicates that both regional industrial emissions and long range transport of Hg from central, south and southwest China were corresponded to the elevated GEM level. Seasonal and diurnal variations of GEM were observed, which reflected variations in source intensity, deposition processes and meteorological factors. Precipitation and throughfall deposition fluxes of THg and MeHg in Mt. Leigong were comparable or lower compared to those reported in Europe and North America, whereas litterfall deposition fluxes of THg and MeHg were higher compared to Europe and North America. This highlights the importance of vegetation to Hg atmospheric cycling. In th remote forest ecosystem of China, deposition of GEM via uptake of foliage followed by litterfall was very important for the depletion of atmospheric Hg. Elevated GEM level in ambient air may accelerate the foliar uptake of Hg through air which may partly explain the elevated litterfall deposition fluxes of Hg observed in Mt. Leigong.

  16. Methods, quality assurance, and data for assessing atmospheric deposition of pesticides in the Central Valley of California

    Science.gov (United States)

    Zamora, Celia; Majewski, Michael S.; Foreman, William T.

    2013-01-01

    The U.S. Geological Survey monitored atmospheric deposition of pesticides in the Central Valley of California during two studies in 2001 and 2002–04. The 2001 study sampled wet deposition (rain) and storm-drain runoff in the Modesto, California, area during the orchard dormant-spray season to examine the contribution of pesticide concentrations to storm runoff from rainfall. In the 2002–04 study, the number and extent of collection sites in the Central Valley were increased to determine the areal distribution of organophosphate insecticides and other pesticides, and also five more sample types were collected. These were dry deposition, bulk deposition, and three sample types collected from a soil box: aqueous phase in runoff, suspended sediment in runoff, and surficial-soil samples. This report provides concentration data and describes methods and quality assurance of sample collection and laboratory analysis for pesticide compounds in all samples collected from 16 sites. Each sample was analyzed for 41 currently used pesticides and 23 pesticide degradates, including oxygen analogs (oxons) of 9 organophosphate insecticides. Analytical results are presented by sample type and study period. The median concentrations of both chloryprifos and diazinon sampled at four urban (0.067 micrograms per liter [μg/L] and 0.515 μg/L, respectively) and four agricultural sites (0.079 μg/L and 0.583 μg/L, respectively) during a January 2001 storm event in and around Modesto, Calif., were nearly identical, indicating that the overall atmospheric burden in the region appeared to be fairly similar during the sampling event. Comparisons of median concentrations in the rainfall to those in the McHenry storm-drain runoff showed that, for some compounds, rainfall contributed a substantial percentage of the concentration in the runoff; for other compounds, the concentrations in rainfall were much greater than in the runoff. For example, diazinon concentrations in rainfall were about

  17. Atmospheric-pressure plasma-enhanced chemical vapor deposition of electrochromic organonickel oxide thin films with an atmospheric pressure plasma jet

    International Nuclear Information System (INIS)

    Deposition of electrochromic organonickel oxide (NiOxCy) films onto glass/indium tin oxide (ITO) substrates using atmospheric-pressure plasma-enhanced chemical vapor deposition with an atmospheric pressure plasma jet under various precursor injection angles is investigated. A precursor [nickelocene, Ni(C5H5)2] vapor, carried by argon gas and mixed with oxygen gas, is injected into an air plasma torch for the deposition of NiOxCy films by a short exposure of the substrate, 20 s, in the plasma. Uniform light modulation on glass/ITO/NiOxCy is produced while the moving glass/ITO substrate is exposed to the plasma torch at room temperature (∼ 23 °C) and under atmospheric pressure. Light modulation with up to a 40.9% transmittance variation at a wavelength of 513.9 nm under Li+ intercalation and de-intercalation in a 1 M LiClO4–propylene carbonate electrolyte is achieved. - Highlights: ► Rapid deposition of electrochromic NiOxCy film by atmospheric pressure plasma jet ► Uniform light modulation on NiOxCy film is produced. ► Nano-grains in NiOxCy films offer fast coloration and bleaching

  18. Atmospheric deposition of mercury in Atlantic Forest and ecological risk to soil fauna

    Science.gov (United States)

    Cristhy Buch, Andressa; Cabral Teixeira, Daniel; Fernandes Correia, Maria Elizabeth; Vieira Silva-Filho, Emmanoel

    2014-05-01

    The increasing levels of mercury (Hg) found in the atmosphere nowadays has a great contribution from anthropogenic sources and has been a great concern in the past two decades in industrialized countries. Brazil is the seventh country with the highest rate of mercury in the atmosphere. Certainly, the petroleum refineries have significant contribution, seen that 100 million m3 of crude oil are annually processed. These refineries contribute with low generation of solid waste; however, a large fraction of Hg can be emitted to the atmosphere. There are sixteen refineries in Brazil, three of them located in the state of Rio de Janeiro. The Hg is a toxic and hazardous trace element, naturally found in the earth crust. The major input of Hg to ecosystems is through atmospheric deposition (wet and dry), being transported in the atmosphere over large distances. The forest biomes are of great importance in the atmosphere/soil cycling of elemental Hg through foliar uptake and subsequent transfer to the soil through litterfall, which play an important role as Hg sink. The Atlantic Forest of Brazil is the greater contributor of fauna and flora biodiversity in the world and, according to recent studies, this biome has the highest concentrations of mercury in litter in the world, as well as in China, at Subtropical Forest. Ecotoxicological assessments can predict the potential ecological risk of Hg toxicity in the soil can lead to impact the soil fauna and indirectly other trophic levels of the food chain within one or more ecosystems. This study aims to determine mercury levels that represent risks to diversity and functioning of soil fauna in tropical forest soils. The study is conducted in two forest areas inserted into conservation units of Rio de Janeiro state. One area is located next to an important petroleum refinery in activity since fifty-two years ago, whereas the other one is located next to other refinery under construction (beginning activities in 2015), which will

  19. Nitric oxide and nitrous oxide emission from Hungarian forest soils; link with atmospheric N-deposition

    Directory of Open Access Journals (Sweden)

    L. Horváth

    2005-06-01

    Full Text Available Studies of forest nitrogen (N budgets generally measure inputs to the atmosphere in wet and dry precipitation and outputs via hydrologic export. Although denitrification has been shown to be important in many wetland ecosystems, emission of nitrogen oxides from forest soils is an important, and often overlooked, component of an ecosystem nitrogen budget. During one year (2002-2003, emissions of nitric oxide (NO and nitrous oxide (N2O were measured from Sessile oak and Norway spruce forest soils in northeast Hungary. Accumulation in small static chambers followed by gas chromatography-mass spectrometry detection was used for the estimation of N2O emission flux. Because there are rapid chemical reactions of NO and ozone, small dynamic chambers were used for in situ NO flux measurements. Average soil emissions of NO were 1.2 and 2.1 µgNm-2h-1, and for N2O were 15 and 20 µgNm-2h-1, for spruce and oak soils, respectively. The previously determined nitrogen balance between the atmosphere and the forest ecosystem was re-calculated using these soil emission figures. The total (dry + wet atmospheric N-deposition to the soil was 1.42 and 1.59gNm-2yr-1 for spruce and oak, respectively, while the soil emissions are 0.14 and 0.20 gNm-2yr-1. Thus, about 10-13% of N compounds deposited to the soil, mostly as NH3/NH4+ and HNO3/NO3-, are transformed in the soil and emitted back to the atmosphere, mostly as a greenhouse gas (N2O.

  20. Analysis of software for modeling atmospheric dispersion

    International Nuclear Information System (INIS)

    During last few years, a number software packages for microcomputes have appeared with the aim to simulate diffusion of atmospheric pollutants. These codes, simplifying the models used for safety analyses of industrial plants are becoming more useful, and are even used for post-accidental conditions. The report presents for the first time in a critical manner, principal models available up to this date. The problem arises in adapting the models to the demanded post-accidental interventions. In parallel to this action an analysis of performance was performed. It means, identifying the need of forecasting the most appropriate actions to be performed having in mind short available time and lack of information. Because of these difficulties, it is possible to simplify the software, which will not include all the options but could deal with a specific situation. This would enable minimisation of data to be collected on the site

  1. Antifouling Transparent ZnO Thin Films Fabricated by Atmospheric Pressure Cold Plasma Deposition

    Science.gov (United States)

    Suzaki, Yoshifumi; Du, Jinlong; Yuji, Toshifumi; Miyagawa, Hayato; Ogawa, Kazufumi

    2015-09-01

    One problem with outdoor-mounted solar panels is that power generation efficiency is reduced by face plate dirt; a problem with electronic touch panels is the deterioration of screen visibility caused by finger grease stains. To solve these problems, we should fabricate antifouling surfaces which have superhydrophobic and oil-repellent properties without spoiling the transparency of the transparent substrate. In this study, an antifouling surface with both superhydrophobicity and oil-repellency was fabricated on a glass substrate by forming a fractal microstructure. The fractal microstructure was constituted of transparent silica particles 100 nm in diameter and transparent zinc-oxide columns grown on silica particles through atmospheric pressure cold plasma deposition; the sample surface was coated with a chemically adsorbed monomolecular layer. Samples were obtained which had a superhydrophobic property (with a water droplet contact angle of more than 150°) and a high average transmittance of about 90% (with wavelengths ranging from 400 nm to 780 nm).

  2. An assessment of the variability in performance of wet atmospheric deposition samplers

    Science.gov (United States)

    Graham, R.C.; Robertson, J.K.; Obal, John

    1987-01-01

    The variability in performance of two brands of wet/dry atmospheric deposition samplers were compared for 1 year at a sincle site. A total of nine samplers were used. Samples were collected weekly and analyzed for pH, specific conductance, common chemical constituents, and sample volume. Additionally, data on the duration of each sampler opening were recorded using a microdatalogger. These data disprove the common perception that samplers remain open throughout a precipitation event. The sensitivity of sampler sensors within the range tested did not have a defineable impact on sample collection. The nonnormal distribution within the data set necessitated application of the nonparametric Friedman Test to assess comparability of sample chemical composition and volume between and within sampler brands. Statistically significant differences existed for most comparisons, however the test did not permit quantification of their magnitudes. Differences in analyte concentrations between samplers were small. (USGS)

  3. Impacts of changing atmospheric deposition chemistry on nitrogen and phosphorus loading to Ganga River (India).

    Science.gov (United States)

    Pandey, Jitendra; Singh, Anand V; Singh, Ashima; Singh, Rachna

    2013-08-01

    Investigations on atmospheric deposition (AD) and water chemistry along a 35 km stretch of Ganga River indicated that although N:P stoichiometry of AD did not change, there were over 1.4-2.0 fold increase in AD-NO₃⁻, AD-NH₄⁺ and AD-PO₄³⁻ overtime. Concentration of dissolved inorganic-N (DIN) in river showed significant positive correlations with AD-NO₃⁻ and runoff DIN. Similarly, dissolved reactive-P (DRP) in river showed significant positive correlation with AD-PO₄³⁻ and runoff DRP. The study shows that AD has become an important source of N and P input to Ganga River.

  4. Combustion of spent shales from the Rotem deposit. Pt. 2. Behavior in oxygen-containing atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Zabicky, J. (Ben-Gurion Univ. of the Negev, Beersheba (Israel). Inst. for Applied Research Ben-Gurion Univ. of the Negev, Beersheba (Israel). M.R. Bloch Center for Coal Research); Wohlfarth, A. (Energy Resources Development Ltd., Mishor Rotem, Arava (Israel))

    1991-09-01

    Spent shales prepared by the Fisher method from oils shales of the Rotem deposit were studied in a continuous fluidized bed reactor at 700-900deg C under atmospheric pressure, using mixtures of nitrogen, oxygen and carbon dioxide as the fluidizing gas. Combustion of the organic residue takes place together with other processes, the most important of which are decomposition of calcium carbonate and gasification of the organic residue by carbon dioxide produced by combustion and carbonate decomposition. The extent to which each of these reactions takes place determines wether the particles undergo predominantly pyrolytic or oxidative processes. This depends on temperature, composition of the fluidizing gas, particle size of the spent shales, and mean residence time of the particles in the reactor. (orig.).

  5. Recharge to extensive aquifers by means of atmospheric chloride deposition and ground temperature

    International Nuclear Information System (INIS)

    One of the most uncertain and at the same time essential values for groundwater knowledge and management is aquifer recharge, especially in large areas with scarce data. Under steady state circumstances the atmospheric chloride deposition balance is an effective method to estimate average diffuse recharge and its possible error. Progress in the application are reported to some aquifers, in some of which the water mixtures in groundwater sampling from the aquifer due to recharge spatial variability are considered. Also, recharge affects in ground temperature distribution is considered as an indicator of recharge. Spanish examples from the Iberian Peninsula: Donana, Anoia, the Llobregat delta, and the whole territory are considered, and also from the archipelagos The Canaries: Gran Canaria, Fuerteventura and La Gomera, and the Balearic Islands: Mallorca. (Author) 19 refs.

  6. Impacts of changing atmospheric deposition chemistry on nitrogen and phosphorus loading to Ganga River (India).

    Science.gov (United States)

    Pandey, Jitendra; Singh, Anand V; Singh, Ashima; Singh, Rachna

    2013-08-01

    Investigations on atmospheric deposition (AD) and water chemistry along a 35 km stretch of Ganga River indicated that although N:P stoichiometry of AD did not change, there were over 1.4-2.0 fold increase in AD-NO₃⁻, AD-NH₄⁺ and AD-PO₄³⁻ overtime. Concentration of dissolved inorganic-N (DIN) in river showed significant positive correlations with AD-NO₃⁻ and runoff DIN. Similarly, dissolved reactive-P (DRP) in river showed significant positive correlation with AD-PO₄³⁻ and runoff DRP. The study shows that AD has become an important source of N and P input to Ganga River. PMID:23700007

  7. Spatial atmospheric atomic layer deposition of InxGayZnzO for thin film transistors.

    Science.gov (United States)

    Illiberi, A; Cobb, B; Sharma, A; Grehl, T; Brongersma, H; Roozeboom, F; Gelinck, G; Poodt, P

    2015-02-18

    We have investigated the nucleation and growth of InGaZnO thin films by spatial atmospheric atomic layer deposition. Diethyl zinc (DEZ), trimethyl indium (TMIn), triethyl gallium (TEGa), and water were used as Zn, In, Ga and oxygen precursors, respectively. The vaporized metal precursors have been coinjected in the reactor. The metal composition of InGaZnO has been controlled by varying the TMIn or TEGa flow to the reactor, for a given DEZ flow and exposure time. The morphology of the films changes from polycrystalline, for ZnO and In-doped ZnO, to amorphous for In-rich IZO and InGaZnO. The use of these films as the active channel in TFTs has been demonstrated and the influence of In and Ga cations on the electrical characteristics of the TFTs has been studied.

  8. Assessing the Emission Sources of Atmospheric Mercury in Wet Deposition Across Illinois, USA

    OpenAIRE

    Gratz L. E.; Keeler G. J.; Dvonch J. T.; Morishita M; Barres J. A.

    2013-01-01

    From August 2007 to August 2009, we collected event-based precipitation samples for mercury (Hg) and trace element analysis at four sites in Illinois, USA. The objectives of these measurements were to quantify the levels of Hg wet deposition across the state, and to assess the contributions to Hg in precipitation from major local and regional emission sources. The measurement sites were located in Chicago, Peoria, Nilwood, and Carbondale, IL. We were not able to identify a clear spatial gradi...

  9. Spatio-temporal variations and influencing factors of polycyclic aromatic hydrocarbons in atmospheric bulk deposition along a plain-mountain transect in western China

    Science.gov (United States)

    Xing, Xinli; Zhang, Yuan; Yang, Dan; Zhang, Jiaquan; Chen, Wei; Wu, Chenxi; Liu, Hongxia; Qi, Shihua

    2016-08-01

    Ten atmospheric bulk deposition (the sum of wet and dry deposition) samplers for polycyclic aromatic hydrocarbons (PAHs) were deployed at a plain-mountain transect (namely PMT transect, from Daying to Qingping) in Chengdu Plain, West China from June 2007 to June 2008 in four consecutive seasons (about every three months). The bulk deposition fluxes of ∑15-PAHs ranged from 169.19 μg m-2 yr-1 to 978.58 μg m-2 yr-1 with geometric mean of 354.22 μg m-2 yr-1. The most prevalent PAHs were 4-ring (39.65%) and 3-ring (35.56%) PAHs. The flux values were comparable to those in rural areas. Higher fluxes of total PAHs were observed in the middle of PMT transect (SL, YX and JY, which were more urbanized than other sites). The seasonal deposition fluxes in the sampling profile indicated seasonality of the contaminant source was an important factor in controlling deposition fluxes. PAHs bulk deposition was negatively correlated with meteorological parameters (temperature, wind speed, humidity, and precipitation). No significant correlations between soil concentrations and atmospheric deposition were found along this transect. PAHs in soil samples had combined sources of coal, wood and petroleum combustion, while a simple source of coal, wood and grass combustion for bulk deposition. There were significant positive correlation relationship (p atmospheric bulk deposition and local PAHs emission, with biomass burning as the major contribution to the total emission of PAHs. This transect acts as an important PAHs source rather than being a sink according to the ratio of deposition/emission. Mountain cold trap effect existed in this transect where the altitude was higher than 1000 m. Long-range transport had an impact on the bulk deposition in summer. And this transect was a source to Tibetan only in summer. The forward trajectory analysis showed most air masses did not undergo long-range transport due to the blocking effect of surrounding mountains. Only a few air masses (<10

  10. Trends in the composition of wet deposition: effects of the atmospheric rehabilitation in East-Germany

    Science.gov (United States)

    Marquardt, Wolfgang; Brüggemann, Erika; Ihle, Peter

    1996-07-01

    The chemical components in precipitation largely depend on type and quantity of emissions on the course of the air masses at the sampling site. Beginning in 1982, the concentrations of major ions in precipitation at initially 3 sites are described in total as well as arrival sectors. For regions with specific geographical or emission features, 5 to 7 sectors for every sampling site are established, e.g., Scandinavia, or the centres of brown coal combustion in the former GDR. Particulary from the sectors of the former GDR, the precipitation was over-averaged contaminated anthropogenically in the years before the political change. Some components were significantly raised in comparison to other sectors. However, acidity remained on the level of the other sectors in the 80s. In the early 90s, anthropogenic emissions were systematically reduced partly by substitution of brown coal of inferior quality, better flue gas cleaning and partly by closing down industries. The effect of such steps on the wet deposition is being studied in a national German SANA research project (SANA: scientific program of rehabilitation of the atmosphere). In this project, the sampling sites were extended to 7 while maintaining the sampling procedure and the recording of relevant meteorological input-data. As a result, there now exists a homogeneous long-term data base allowing us to study the effects of emissions on wet deposition by the rehabilitation of the atmosphere in the former GDR. The paper focusses on changes in sulphate, nitrate, calcium, acidity, chloride and potassium concentrations in precipitation at the 3 so-called long-term sites. There are conspicuous decreases of some ions on one hand, but there is also an increase of nitrate and acidity, especially in recent years.

  11. Lightning driven inner radiation belt energy deposition into the atmosphere: regional and global estimates

    Directory of Open Access Journals (Sweden)

    C. J. Rodger

    2005-12-01

    Full Text Available In this study we examine energetic electron precipitation fluxes driven by lightning, in order to determine the global distribution of energy deposited into the middle atmosphere. Previous studies using lightning-driven precipitation burst rates have estimated losses from the inner radiation belts. In order to confirm the reliability of those rates and the validity of the conclusions drawn from those studies, we have analyzed New Zealand data to test our global understanding of troposphere to magnetosphere coupling. We examine about 10000h of AbsPAL recordings made from 17 April 2003 through to 26 June 2004, and analyze subionospheric very-low frequency (VLF perturbations observed on transmissions from VLF transmitters in Hawaii (NPM and western Australia (NWC. These observations are compared with those previously reported from the Antarctic Peninsula. The perturbation rates observed in the New Zealand data are consistent with those predicted from the global distribution of the lightning sources, once the different experimental configurations are taken into account. Using lightning current distributions rather than VLF perturbation observations we revise previous estimates of typical precipitation bursts at L~2.3 to a mean precipitation energy flux of ~1×10-3 ergs cm-2s-1. The precipitation of energetic electrons by these bursts in the range L=1.9-3.5 will lead to a mean rate of energy deposited into the atmosphere of 3×10-4 ergs cm-2min-1, spatially varying from a low of zero above some ocean regions to highs of ~3-6×10-3 ergs cm-2min-1 above North America and its conjugate region.

  12. Phytoplankton responses to atmospheric metal deposition in the coastal and open-ocean Sargasso Sea

    Directory of Open Access Journals (Sweden)

    Katherine Rose Marie Mackey

    2012-10-01

    Full Text Available This study investigated the impact of atmospheric metal deposition on natural phytoplankton communities at open-ocean and coastal sites in the Sargasso Sea during the spring bloom. Locally collected aerosols with different metal contents were added to natural phytoplankton assemblages from each site, and changes in nitrate, dissolved metal concentration, and phytoplankton abundance and carbon content were monitored. Addition of aerosol doubled the concentrations of cadmium, cobalt, copper, iron, manganese and nickel in the incubation water. Over the three-day experiments, greater drawdown of dissolved metals occurred in the open ocean water, whereas little metal drawdown occurred in the coastal water. Two populations of picoeukaryotic algae and Synechococcus grew in response to aerosol additions in both experiments. Particulate organic carbon (POC increased and was most sensitive to changes in picoeukaryote abundance. Phytoplankton community composition differed depending on the chemistry of the aerosol added. Enrichment with aerosol that had higher metal content led to a 10-fold increase in Synechococcus abundance in the oceanic experiment but not in the coastal experiment. Enrichment of aerosol-derived cobalt (Co, manganese, and nickel were particularly enhanced in the oceanic experiment, suggesting the Synechococcus population may have been fertilized by these aerosol metals. Copper (Cu-binding ligand concentrations were in excess of dissolved Cu in both experiments, and increased with aerosol additions. Bioavailable free hydrated Cu2+ concentrations were below toxicity thresholds throughout both experiments. These experiments show (1 atmospheric deposition contributes biologically important metals to seawater, (2 these metals are consumed over time scales commensurate with cell growth, and (3 growth responses can differ between distinct Synechococcus or eukaryotic algal populations despite relatively close geographic proximity and taxonomic

  13. Quantitative analysis of diamond deposition reactor efficiency

    International Nuclear Information System (INIS)

    Graphical abstract: Surface H atom densities in a diamond deposition plasma reactor and the highest predicted value (black line). A 350 μm diamond crystal grown at 70 μm/h. Highlights: ► Electron temperature measurement at high pressure in diamond deposition reactor. ► H-atom density measurements at high pressure and high power in diamond deposition reactor. ► Surface H-atom density measurements at high pressure and high power in diamond deposition reactor. ► Microwave cavity based reactor efficiency compared to others reactors. - Abstract: Optical emission spectroscopy has been used to characterize diamond deposition microwave chemical vapour deposition (MWCVD) plasmas operating at high power density. Electron temperature has been deduced from H atom emission lines while H-atom mole fraction variations have been estimated using actinometry technique, for a wide range of working conditions: pressure 25–400 hPa and MW power 600–4000 W. An increase of the pressure from 14 hPa to 400 hPa with a simultaneous increase in power causes an electron temperature decrease from 17,000 K to 10,000 K and a H atom mole fraction increase from 0.1 to up to 0.6. This last value however must be considered as an upper estimate due to some assumptions made as well as experimental uncertainties.

  14. Assessing the Sources of Atmospheric Mercury Wet Deposited in Florida, USA

    Directory of Open Access Journals (Sweden)

    Dvonch J. T.

    2013-04-01

    Full Text Available From October 2008 through August 2010, event-based precipitation samples for mercury (Hg, trace elements, and major ions analysis were collected at six monitoring sites in Florida, USA. The objectives of these measurements were to quantify the levels of Hg wet deposition across the state, and to assess the contributions to Hg in precipitation from major local and regional emission sources in support of a Hg Total Maximum Daily Load (TMDL project. The measurement sites were located in Pensacola, Jacksonville, Orlando, Tampa, Davie, and Everglades National Park. For the period April 2009 through August 2010, Hg wet deposition rates ranged from 26.8 to 38.7 μg/m2 across the six sites. We observed a strong seasonal pattern, with increases in measured Hg concentrations and Hg wet deposition occurring during the summer months, which was further pronounced at the southern sites. We also observed a clear overall spatial gradient in Hg wet deposition, increasing across sites from north to south.

  15. Multi-model Mean Nitrogen and Sulfur Deposition from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP): Evaluation of Historical and Projected Future Changes

    Energy Technology Data Exchange (ETDEWEB)

    Lamarque, Jean-Francois; Dentener, Frank; McConnell, J.R.; Ro, C-U; Shaw, Mark; Vet, Robert; Bergmann, D.; Cameron-Smith, Philip; Dalsoren, S.; Doherty, R.; Faluvegi, G.; Ghan, Steven J.; Josse, B.; Lee, Y. H.; MacKenzie, I. A.; Plummer, David; Shindell, Drew; Skeie, R. B.; Stevenson, D. S.; Strode, S.; Zeng, G.; Curran, M.; Dahl-Jensen, D.; Das, S.; Fritzsche, D.; Nolan, M.

    2013-08-20

    We present multi-model global datasets of nitrogen and sulfate deposition covering time periods from 1850 to 2100, calculated within the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The computed deposition fluxes are compared to surface wet deposition and ice-core measurements. We use a new dataset of wet deposition for 2000-2002 based on critical assessment of the quality of existing regional network data. We show that for present-day (year 2000 ACCMIP time-slice), the ACCMIP results perform similarly to previously published multi-model assessments. The analysis of changes between 1980 and 2000 indicates significant differences between model and measurements over the United States, but less so over Europe. This difference points towards misrepresentation of 1980 NH3 emissions over North America. Based on ice-core records, the 1850 deposition fluxes agree well with Greenland ice cores but the change between 1850 and 2000 seems to be overestimated in the Northern Hemisphere for both nitrogen and sulfur species. Using the Representative Concentration Pathways to define the projected climate and atmospheric chemistry related emissions and concentrations, we find large regional nitrogen deposition increases in 2100 in Latin America, Africa and parts of Asia under some of the scenarios considered. Increases in South Asia are especially large, and are seen in all scenarios, with 2100 values more than double 2000 in some scenarios and reaching >1300 mgN/m2/yr averaged over regional to continental scale regions in RCP 2.6 and 8.5, ~30-50% larger than the values in any region currently (2000). Despite known issues, the new ACCMIP deposition dataset provides novel, consistent and evaluated global gridded deposition fields for use in a wide range of climate and ecological studies.

  16. Mosses as biomonitors of atmospheric heavy metal deposition: Spatial patterns and temporal trends in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Harmens, H., E-mail: hh@ceh.ac.u [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Norris, D.A., E-mail: danor@ceh.ac.u [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Steinnes, E., E-mail: Eiliv.Steinnes@chem.ntnu.n [Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim (Norway); Kubin, E., E-mail: Eero.Kubin@metla.f [Finnish Forest Research Institute, Kirkkosaarentie 7, 91500 Muhos (Finland); Piispanen, J., E-mail: Juha.Piispanen@metla.f [Finnish Forest Research Institute, Kirkkosaarentie 7, 91500 Muhos (Finland); Alber, R., E-mail: Renate.Alber@provinz.bz.i [Environmental Agency of Bolzano, 39055 Laives (Italy); Aleksiayenak, Y., E-mail: beataa@gmail.co [International Sakharov Environmental University, Minsk (Belarus); Blum, O., E-mail: blum@nbg.kiev.u [National Botanical Garden, Academy of Science of Ukraine, Timiryazevs' ka St. 1, 01014 Kyiv (Ukraine); Coskun, M., E-mail: coskunafm@yahoo.co [Canakkale Onsekiz Mart University, 17100 Canakkale (Turkey); Dam, M., E-mail: mariad@us.f [Environment Agency, Traoagota 38, FO-165 Argir (Faroe Islands); De Temmerman, L., E-mail: ludet@var.fgov.b [Veterinary and Agrochemical Research Centre, Leuvensesteenweg 17, 3080 Tervuren (Belgium); Fernandez, J.A., E-mail: jangel.fernandez@usc.e [University of Santiago de Compestela, Faculty of Biology, Department of Ecology, 15782 Santiago de Compostela (Spain); Frolova, M., E-mail: marina.frolova@lvgma.gov.l [Latvian Environment, Geology and Meteorology Agency, Maskavas Str. 165, Riga LV 1019 (Latvia); Frontasyeva, M., E-mail: marina@nf.jinr.r [Joint Institute for Nuclear Research, Str. Joliot-Curie 6, 141980 Dubna (Russian Federation); Gonzalez-Miqueo, L., E-mail: lgonzale2@alumni.unav.e [University of Navarra, Irunlarrea No 1, 31008 Pamplona (Spain)

    2010-10-15

    In recent decades, mosses have been used successfully as biomonitors of atmospheric deposition of heavy metals. Since 1990, the European moss survey has been repeated at five-yearly intervals. Although spatial patterns were metal-specific, in 2005 the lowest concentrations of metals in mosses were generally found in Scandinavia, the Baltic States and northern parts of the UK; the highest concentrations were generally found in Belgium and south-eastern Europe. The recent decline in emission and subsequent deposition of heavy metals across Europe has resulted in a decrease in the heavy metal concentration in mosses for the majority of metals. Since 1990, the concentration in mosses has declined the most for arsenic, cadmium, iron, lead and vanadium (52-72%), followed by copper, nickel and zinc (20-30%), with no significant reduction being observed for mercury (12% since 1995) and chromium (2%). However, temporal trends were country-specific with sometimes increases being found. - Since 1990, heavy metal concentrations in mosses have declined in Europe for most metals.

  17. Deposition of atmospheric (137)Cs in Japan associated with the Asian dust event of March 2002.

    Science.gov (United States)

    Fujiwara, Hideshi; Fukuyama, Taijiro; Shirato, Yasuhito; Ohkuro, Toshiya; Taniyama, Ichiro; Zhang, Tong-Hui

    2007-10-01

    Considerable deposition of (137)Cs was observed in the northwestern coastal area of Japan in March 2002. Since there were no nuclear explosions or serious nuclear accidents in the early 2000s, transport of previously contaminated dust appears to be the only plausible explanation for this event. In March 2002, there was a massive sandstorm on the East Asian continent, and the dust raised by the storm was transported across the sea to Japan. This dust originated in Mongolia and northeastern China, in an area distant from the Chinese nuclear test site at Lop Nor or any other known possible sources of (137)Cs. Our radioactivity measurements showed (137)Cs enrichment in the surface layer of grassland soils in the area of the sandstorm, which we attributed to accumulation as a result of past nuclear testing. We suggest that the grassland is a potential source of (137)Cs-bearing soil particles. Since the late 1990s, this area has experienced drought conditions, resulting in a considerable reduction of vegetation cover. We attribute the prodigious release of (137)Cs-bearing soil particles into the atmosphere during the sandstorm and the subsequent deposition of (137)Cs in Japan to this change.

  18. Mechanistic modeling study on process optimization and precursor utilization with atmospheric spatial atomic layer deposition

    International Nuclear Information System (INIS)

    Spatial atomic layer deposition (SALD) is a promising technology with the aim of combining the advantages of excellent uniformity and conformity of temporal atomic layer deposition (ALD), and an industrial scalable and continuous process. In this manuscript, an experimental and numerical combined model of atmospheric SALD system is presented. To establish the connection between the process parameters and the growth efficiency, a quantitative model on reactant isolation, throughput, and precursor utilization is performed based on the separation gas flow rate, carrier gas flow rate, and precursor mass fraction. The simulation results based on this model show an inverse relation between the precursor usage and the carrier gas flow rate. With the constant carrier gas flow, the relationship of precursor usage and precursor mass fraction follows monotonic function. The precursor concentration, regardless of gas velocity, is the determinant factor of the minimal residual time. The narrow gap between precursor injecting heads and the substrate surface in general SALD system leads to a low Péclet number. In this situation, the gas diffusion act as a leading role in the precursor transport in the small gap rather than the convection. Fluid kinetics from the numerical model is independent of the specific structure, which is instructive for the SALD geometry design as well as its process optimization

  19. Chemical vapor deposition of high quality graphene films from carbon dioxide atmospheres.

    Science.gov (United States)

    Strudwick, Andrew James; Weber, Nils Eike; Schwab, Matthias Georg; Kettner, Michel; Weitz, R Thomas; Wünsch, Josef R; Müllen, Klaus; Sachdev, Hermann

    2015-01-27

    The realization of graphene-based, next-generation electronic applications essentially depends on a reproducible, large-scale production of graphene films via chemical vapor deposition (CVD). We demonstrate how key challenges such as uniformity and homogeneity of the copper metal substrate as well as the growth chemistry can be improved by the use of carbon dioxide and carbon dioxide enriched gas atmospheres. Our approach enables graphene film production protocols free of elemental hydrogen and provides graphene layers of superior quality compared to samples produced by conventional hydrogen/methane based CVD processes. The substrates and resulting graphene films were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Raman microscopy, sheet resistance and transport measurements. The superior quality of the as-grown graphene films on copper is indicated by Raman maps revealing average G band widths as low as 18 ± 8 cm(-1) at 514.5 nm excitation. In addition, high charge carrier mobilities of up to 1975 cm(2)/(V s) were observed for electrons in transferred films obtained from a carbon dioxide based growth protocol. The enhanced graphene film quality can be explained by the mild oxidation properties of carbon dioxide, which at high temperatures enables an uniform conditioning of the substrates by an efficient removal of pre-existing and emerging carbon impurities and a continuous suppression and in situ etching of carbon of lesser quality being co-deposited during the CVD growth. PMID:25398132

  20. Thresholds for protecting Pacific Northwest ecosystems from atmospheric deposition of nitrogen: state of knowledge report

    Science.gov (United States)

    Cummings, Tonnie; Blett, Tamara; Porter, Ellen; Geiser, Linda; Graw, Rick; McMurray, Jill; Perakis, Steven S.; Rochefort, Regina

    2014-01-01

    The National Park Service and U.S. Forest Service manage areas in the states of Idaho, Oregon, and Washington – collectively referred to in this report as the Pacific Northwest - that contain significant natural resources and provide many recreational opportunities. The agencies are mandated to protect the air quality and air pollution-sensitive resources on these federal lands. Human activity has greatly increased the amount of nitrogen emitted to the atmosphere, resulting in elevated amounts of nitrogen being deposited in park and forest ecosystems. There is limited information in the Pacific Northwest about the levels of nitrogen that negatively affect natural systems, i.e., the critical loads. The National Park Service and U.S. Forest Service, with scientific input from the U.S. Geological Survey, have developed an approach for accumulating additional nitrogen critical loads information in the Pacific Northwest and using the data in planning and regulatory arenas. As a first step in that process, this report summarizes the current state of knowledge about nitrogen deposition, effects, and critical loads in the region. It also describes ongoing research efforts and identifies and prioritizes additional data needs.

  1. Atmospheric pressure plasma deposition of antimicrobial coatings on non-woven textiles

    Science.gov (United States)

    Nikiforov, Anton Yu.; Deng, Xiaolong; Onyshchenko, Iuliia; Vujosevic, Danijela; Vuksanovic, Vineta; Cvelbar, Uros; De Geyter, Nathalie; Morent, Rino; Leys, Christophe

    2016-08-01

    A simple method for preparation of nanoparticle incorporated non-woven fabric with high antibacterial efficiency has been proposed based on atmospheric pressure plasma process. In this work direct current plasma jet stabilized by fast nitrogen flow was used as a plasma deposition source. Three different types of the nanoparticles (silver, copper and zinc oxide nanoparticles) were employed as antimicrobial agents. X-ray photoelectron spectroscopy (XPS) measurements have shown a positive chemical shift observed for Ag 3d 5/2 (at 368.1 eV) suggests that silver nanoparticles (AgNPs) are partly oxidized during the deposition. The surface chemistry and the antibacterial activity of the samples against Staphylococcus aureus and Escherichia coli were investigated and analyzed. It is shown that the samples loaded with nanoparticles of Ag and Cu and having the barrier layer of 10 nm characterized by almost 97% of bacterial reduction whereas the samples with ZnO nanoparticles provide 86% reduction of Staphylococcus aureus. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  2. Deposition of atmospheric (137)Cs in Japan associated with the Asian dust event of March 2002.

    Science.gov (United States)

    Fujiwara, Hideshi; Fukuyama, Taijiro; Shirato, Yasuhito; Ohkuro, Toshiya; Taniyama, Ichiro; Zhang, Tong-Hui

    2007-10-01

    Considerable deposition of (137)Cs was observed in the northwestern coastal area of Japan in March 2002. Since there were no nuclear explosions or serious nuclear accidents in the early 2000s, transport of previously contaminated dust appears to be the only plausible explanation for this event. In March 2002, there was a massive sandstorm on the East Asian continent, and the dust raised by the storm was transported across the sea to Japan. This dust originated in Mongolia and northeastern China, in an area distant from the Chinese nuclear test site at Lop Nor or any other known possible sources of (137)Cs. Our radioactivity measurements showed (137)Cs enrichment in the surface layer of grassland soils in the area of the sandstorm, which we attributed to accumulation as a result of past nuclear testing. We suggest that the grassland is a potential source of (137)Cs-bearing soil particles. Since the late 1990s, this area has experienced drought conditions, resulting in a considerable reduction of vegetation cover. We attribute the prodigious release of (137)Cs-bearing soil particles into the atmosphere during the sandstorm and the subsequent deposition of (137)Cs in Japan to this change. PMID:17604085

  3. Mechanistic modeling study on process optimization and precursor utilization with atmospheric spatial atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Zhang; He, Wenjie; Duan, Chenlong [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Chen, Rong, E-mail: rongchen@mail.hust.edu.cn [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Shan, Bin [State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

    2016-01-15

    Spatial atomic layer deposition (SALD) is a promising technology with the aim of combining the advantages of excellent uniformity and conformity of temporal atomic layer deposition (ALD), and an industrial scalable and continuous process. In this manuscript, an experimental and numerical combined model of atmospheric SALD system is presented. To establish the connection between the process parameters and the growth efficiency, a quantitative model on reactant isolation, throughput, and precursor utilization is performed based on the separation gas flow rate, carrier gas flow rate, and precursor mass fraction. The simulation results based on this model show an inverse relation between the precursor usage and the carrier gas flow rate. With the constant carrier gas flow, the relationship of precursor usage and precursor mass fraction follows monotonic function. The precursor concentration, regardless of gas velocity, is the determinant factor of the minimal residual time. The narrow gap between precursor injecting heads and the substrate surface in general SALD system leads to a low Péclet number. In this situation, the gas diffusion act as a leading role in the precursor transport in the small gap rather than the convection. Fluid kinetics from the numerical model is independent of the specific structure, which is instructive for the SALD geometry design as well as its process optimization.

  4. Reconstruction of historical atmospheric deposition of DDT in the Zempoala Lagoon, in the center of Mexico

    Science.gov (United States)

    van, Afferden M.; Hansen, A.M.; Fuller, C.C.

    2005-01-01

    Historical trend in deposition of DDT and its metabolites has been reconstructed by analyzing sediment cores of the Zempoala Lagoon, in the center of Mexico. The small watershed of this mountain lagoon is closed, and it is located between 2.800 and 3.700 masl. It ls neither affected by agriculture nor by permanent populations. The Zempoala Lagoon has an average depth of 3.9 mand a maximum depth of 8.8 m. Sediments were extracted with a eore sampler and analyzed by isotope methods (137CS and 2'OPb) for dating. Average sedimentation rate was determined in 0.129 9 cm" yr', corresponding to a maximum age of the 44 cm eore of approximately 60 years. The first presence of total-DDT oecurs in a depth between 28 and 32 cm of the sediment profile, corresponding to the 1960's, with a concentration of 5.3 I1g kg-'. The maximum eoncentration of total-DDT (13.0I1g kg-') occurs in sediment layers representing the late 1970's and beginning 1980's. More recently the concentration decreases towards the present concentration of 1.6 I1g kg-'. This concentration is below most DDT levels reported in recent sediment studies in the USA. The results indicate that the Zempoala Lagoon represents a natural reeipient for studies of the reconstruction of historical trends of atmospheric contaminant deposition in this region. The limitations of the methodology applied, due to the influenee of biodegradation on the definition of correct historical coneentrations of DDT depositions, are demonstrated.

  5. Atmospheric deposition of mercury and methylmercury to landscapes and waterbodies of the Athabasca oil sands region.

    Science.gov (United States)

    Kirk, Jane L; Muir, Derek C G; Gleason, Amber; Wang, Xiaowa; Lawson, Greg; Frank, Richard A; Lehnherr, Igor; Wrona, Fred

    2014-07-01

    Atmospheric deposition of metals originating from a variety of sources, including bitumen upgrading facilities and blowing dusts from landscape disturbances, is of concern in the Athabasca oil sands region of northern Alberta, Canada. Mercury (Hg) is of particular interest as methylmercury (MeHg), a neurotoxin which bioaccumulates through foodwebs, can reach levels in fish and wildlife that may pose health risks to human consumers. We used spring-time sampling of the accumulated snowpack at sites located varying distances from the major developments to estimate winter 2012 Hg loadings to a ∼20 000 km(2) area of the Athabasca oil sands region. Total Hg (THg; all forms of Hg in a sample) loads were predominantly particulate-bound (79 ± 12%) and increased with proximity to major developments, reaching up to 1000 ng m(-2). MeHg loads increased in a similar fashion, reaching up to 19 ng m(-2) and suggesting that oil sands developments are a direct source of MeHg to local landscapes and water bodies. Deposition maps, created by interpolation of measured Hg loads using geostatistical software, demonstrated that deposition resembled a bullseye pattern on the landscape, with areas of maximum THg and MeHg loadings located primarily between the Muskeg and Steepbank rivers. Snowpack concentrations of THg and MeHg were significantly correlated (r = 0.45-0.88, p < 0.01) with numerous parameters, including total suspended solids (TSS), metals known to be emitted in high quantities from the upgraders (vanadium, nickel, and zinc), and crustal elements (aluminum, iron, and lanthanum), which were also elevated in this region. Our results suggest that at snowmelt, a complex mixture of chemicals enters aquatic ecosystems that could impact biological communities of the oil sands region.

  6. Sphagnum mosses as archives of recent and past atmospheric lead deposition in Switzerland

    Science.gov (United States)

    Weiss, Dominik; Shotyk, William; Kramers, Jan D.; Gloor, Marlies

    Sphagnum mosses received from a herbarium and collected recently from a peat bog surface, were used to assess the isotopic character of past and recent atmospheric Pb deposition in Switzerland and to constrain possible Pb sources. Lead removed from the moss surface was isotopically similar to that measured in the corresponding solid plant, suggesting that neither preservative actions for the herbarium samples nor dust had affected the isotopic composition of the samples. The addition of HCl to aqueous extracts to remove surface particles from the plants released more Pb compared to H 2O alone. The changes in isotope ratios between Sphagnum collected during the past c. 130 yr were significantly greater than the small fluctuations between and among species collected at any one time. Three isotope ratio plots and emission inventories indicated that the most likely source of atmospheric Pb was coal-burning at the turn of the century, fly ash from waste incineration until approximately 1950, and gasoline combustion after that. The pollution record derived from the Sphagnum plants is in good agreement with other archives from Switzerland (peat, sediment, ice) and with other herbarium records in Europe.

  7. VALDRIFT 1.0: A valley atmospheric dispersion model with deposition

    Energy Technology Data Exchange (ETDEWEB)

    Allwine, K.J.; Bian, X.; Whiteman, C.D.

    1995-05-01

    VALDRIFT version 1.0 is an atmospheric transport and diffusion model for use in well-defined mountain valleys. It is designed to determine the extent of ddft from aedal pesticide spraying activities, but can also be applied to estimate the transport and diffusion of various air pollutants in valleys. The model is phenomenological -- that is, the dominant meteorological processes goveming the behavior of the valley atmosphere are formulated explicitly in the model, albeit in a highly parameterized fashion. The key meteorological processes treated are: (1) nonsteady and nonhomogeneous along-valley winds and turbulent diffusivities, (2) convective boundary layer growth, (3) inversion descent, (4) noctumal temperature inversion breakup, and (5) subsidence. The model is applicable under relatively cloud-free, undisturbed synoptic conditions and is configured to operate through one diumal cycle for a single valley. The inputs required are the valley topographical characteristics, pesticide release rate as a function of time and space, along-valley wind speed as a function of time and space, temperature inversion characteristics at sunrise, and sensible heat flux as a function of time following sunrise. Default values are provided for certain inputs in the absence of detailed observations. The outputs are three-dimensional air concentration and ground-level deposition fields as a function of time.

  8. Atmospheric deposition and lake chemistry trends at a high mountain site in the eastern Alps

    Directory of Open Access Journals (Sweden)

    Bertha THALER

    2000-02-01

    Full Text Available Records of atmospheric precipitation chemistry starting in 1983 and a series of limnological investigations at two high mountain reference lakes starting in 1988 enable us to describe the response of lake water chemistry to changes in precipitation chemistry and climate. The lakes are located at an altitude well above the timberline in a watershed composed of acidic rocks. Despite the observed reduction in the sulphur atmospheric deposition, the reference lakes showed no corresponding decline in sulphate concentrations, but a marked increase in the acid neutralising capacity was apparent. Changes of the seasonal distribution pattern of the precipitation amounts and a general increase of the air temperature have likely produced an increased weathering which increased the concentration of many inlake solutes and drove the lakes toward more buffered conditions. This phenomenon superimposed to changes like other physical factors (radiation, nutritional conditions and biological factors (enhanced production, competition, predation has produced in the last years greater modifications than merely those to be expected from the decreased acidic input.

  9. Distributed emergency response system to model dispersion and deposition of atmospheric releases

    International Nuclear Information System (INIS)

    Aging hardware and software and increasing commitments by the Departments of Energy and Defense have led us to develop a new, expanded system to replace the existing Atmospheric Release Advisory Capability (ARAC) system. This distributed, computer-based, emergency response system is used by state and federal agencies to assess the environmental health hazards resulting from an accidental release of radioactive material into the atmosphere. Like its predecessor, the expanded system uses local meteorology (e.g., wind speed and wind direction), as well as terrain information, to simulate the transport and dispersion of the airborne material. The system also calculates deposition and dose and displays them graphically over base maps of the local geography for use by on-site authorities. This paper discusses the limitations of the existing ARAC system. It also discusses the components and functionality of the new system, the technical difficulties encountered and resolved in its design and implementation, and the software methodologies and tools employed in its development

  10. Use of the lichen Xanthoria mandschurica in monitoring atmospheric elemental deposition in the Taihang Mountains, Hebei, China

    OpenAIRE

    Hua-Jie Liu; Liang-Cheng Zhao; Shi-Bo Fang; Si-Wa Liu; Jian-Sen Hu; Lei Wang; Xiao-Di Liu; Qing-Feng Wu

    2016-01-01

    Air pollution is a major concern in China. Lichens are a useful biomonitor for atmospheric elemental deposition but have rarely been used in North China. The aim of this study was to investigate the atmospheric depositions of 30 trace elements (Al, Ba, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, Sb, Sc, Sm, Sr, Tb, Th, Ti, Tl, V and Zn) in a region of the Taihang Mountains, Hebei Province, China using lichens as biomonitors. Epilithic foliose lichen Xanthoria mandsch...

  11. Ammonium first: natural mosses prefer atmospheric ammonium but vary utilization of dissolved organic nitrogen depending on habitat and nitrogen deposition.

    Science.gov (United States)

    Liu, Xue-Yan; Koba, Keisuke; Makabe, Akiko; Li, Xiao-Dong; Yoh, Muneoki; Liu, Cong-Qiang

    2013-07-01

    Mosses, among all types of terrestrial vegetation, are excellent scavengers of anthropogenic nitrogen (N), but their utilization of dissolved organic N (DON) and their reliance on atmospheric N remain uncharacterized in natural environments, which obscures their roles in N cycles. Natural (15) N abundance of N sources (nitrate (NO(3)(-)), ammonium (NH(4)(+)) and DON in deposition and soil) for epilithic and terricolous mosses was analyzed at sites with different N depositions at Guiyang, China. Moss NO(3)(-) assimilation was inhibited substantially by the high supply of NH(4)(+) and DON. Therefore, contributions of NH(4)(+) and DON to moss N were partitioned using isotopic mass-balance methods. The N contributions averaged 56% and 46% from atmospheric NH(4)(+), and 44% and 17% from atmospheric DON in epilithic and terricolous mosses, respectively. In terricolous mosses, soil NH(4)(+) and soil DON accounted for 16% and 21% of bulk N, which are higher than current estimations obtained using (15) N-labeling methods. Moreover, anthropogenic NH(4)(+) deposition suppressed utilization of DON and soil N because of the preference of moss for NH(4)(+) under elevated NH(4)(+) deposition. These results underscore the dominance of, and preference for, atmospheric NH(4)(+) in moss N utilization, and highlight the importance of considering DON and soil N sources when estimating moss N sequestration and the impacts of N deposition on mosses. PMID:23692546

  12. Superconducting MgB2 film prepared by chemical vapor deposition at atmospheric pressure of N2

    International Nuclear Information System (INIS)

    A simple and effective chemical vapor deposition equipment was developed for deposition of superconducting MgB2 thin films. The pure precursor Boron films were prepared in base pressure of low vacuum and deposited in atmospheric pressure. After the precursor film annealed in Mg vapor, the superconducting MgB2 film was fabricated. During the precursor Boron films preparation, N2 and Ar were used as carrier gas. Compared to Ar gas, the films show better crystallization, surface morphology and superconducting performance when N2 is adopted as carrier gas. With flow rate of 200 sccm of N2 gas, the fabricated MgB2 films exhibit the highest superconducting transition temperature of 39.5 K, which is among the best results of MgB2 thin films. This method provides a suitable method to realize high quality MgB2 Josephson junctions and industrial manufacture of MgB2 superconducting thin films on a large scale. - Highlights: • Boron films were deposited in atmospheric pressure. • Boron films deposited in N2 atmosphere have better morphology than that of in Ar. • MgB2 films show better crystallization and superconductivity in N2 atmosphere

  13. Box-modelling of the impacts of atmospheric nitrogen deposition and benthic remineralisation on the nitrogen cycle of the eastern tropical South Pacific

    Science.gov (United States)

    Su, Bei; Pahlow, Markus; Oschlies, Andreas

    2016-09-01

    Both atmospheric deposition and benthic remineralisation influence the marine nitrogen cycle, and hence ultimately also marine primary production. The biological and biogeochemical relations in the eastern tropical South Pacific (ETSP) among nitrogen deposition, benthic denitrification and phosphorus regeneration are analysed in a prognostic box model of the oxygen, nitrogen and phosphorus cycles in the ETSP. Atmospheric nitrogen deposition ( ≈ 1.5 Tg N yr-1 for the years 2000-2009) is offset by half in the model by reduced N2 fixation, with the other half transported out of the model domain. Model- and data-based benthic denitrification in our model domain are responsible for losses of 0.19 and 1.0 Tg Tg N yr-1, respectively, and both trigger nitrogen fixation, partly compensating for the NO3- loss. Model- and data-based estimates of enhanced phosphate release via sedimentary phosphorus regeneration under suboxic conditions are 0.062 and 0.11 Tg N yr-1, respectively. Since phosphate is the ultimate limiting nutrient in the model, even very small additional phosphate inputs stimulate primary production and subsequent export production and NO3- loss in the oxygen minimum zone (OMZ). A sensitivity analysis of the local response to both atmospheric deposition and benthic remineralisation indicates dominant stabilising feedbacks in the ETSP, which tend to keep a balanced nitrogen inventory; i.e. nitrogen input by atmospheric deposition is counteracted by decreasing nitrogen fixation; NO3- loss via benthic denitrification is partly compensated for by increased nitrogen fixation; enhanced nitrogen fixation stimulated by phosphate regeneration is partly counteracted by stronger water-column denitrification. Even though the water column in our model domain acts as a NO3- source, the ETSP including benthic denitrification might be a NO3- sink.

  14. Atmospheric deposition of selected chemicals and their effect on nonpoint-source pollution in the Twin Cities Metropolitan Area, Minnesota

    Science.gov (United States)

    Brown, R.G.

    1984-01-01

    Atmospheric deposition and subsequent runoff concentrations of total Kjeldahl nitrogen, dissolved nitrite-plus-nitrate nitrogen, total phosphorus, total sulfate (only for atmospheric deposition), total chloride, and total lead were studied from April 1 to October 31, 1980, in one rural and three urban watersheds in the Twin Cities Metropolitan Area, Minnesota. Seasonal patterns of wetfall and dryfall generally were similar for all constituents except chloride in both rural and urban watersheds. Similarity between constituents and between rural and urban watersheds suggested that regional air masses transported from the Gulf of Mexico by frontal storm movements influence seasonal patterns of atmospheric deposition in the metropolitan area. Local influences such as industrial, agricultural, and vehicular air pollutants were found to influence the magnitude or rate of atmospheric deposition rather than the seasonal pattern. Chloride was primarily influenced by northwest frontal storms laden with coastal chloride. Local influences such as dust from road deicing salt dust are thought to have caused an increase in atmospheric chloride during June.

  15. Combining In SITU And Multi-Sensor Satellite Data To Assess The Impact Of Atmospheric Deposition In Lake Garda

    Science.gov (United States)

    Giardino, Claudia; Bresciani, Mariano; Cazzaniga, Ilaria; Di Nicolantonio, Walter; Cacciari, Alessandra; Matta, Erica; Rampini, Anna; Gianinetto, Marco; Ober, Giovanna

    2013-12-01

    In this study we investigated the effect of the deposition of Saharan dust on the phytoplankton growth (i.e. dust fertilization hypothesis) in Lake Garda, an oligotrophic basin with low nutrient and low chlorophyll-a (chl-a) concentration, by combining satellite data with in situ measurements. A Saharan dust event has been recognised on 28/07/2005 by: (i) SEVIRI (Spinning Enhanced Visible and InfraRed Imager) data processing, (ii) a significant increase of PM10 with respect to PM2.5 in a site southern the lake; and (iii) the high values of AOT (aerosol optical thickness) with corresponding low values of the Angstrom parameter measured by AERONET in Ispra. Few days later, an increase of chl-a in the lake was detected from MERIS (Medium Resolution Imaging Spectrometer). The images were processed with the Case-2 Regional (C2R) processor that provided values comparable to in situ measurements (r=0.78). Therefore, preliminary results seem to indicate a response of the Lake Garda in terms of increasing of chl-a as a consequence of the Saharan dust event recognised on 28/07/2005. Nevertheless, the analysis of further events is mandatory in order to have confirmation (or no), about the linkage between atmospheric deposition and phytoplankton dynamics in the study area.

  16. Atmospheric pressure chemical vapour deposition of SnSe and SnSe{sub 2} thin films on glass

    Energy Technology Data Exchange (ETDEWEB)

    Boscher, Nicolas D.; Carmalt, Claire J.; Palgrave, Robert G. [Department of Chemistry, University College London, 20 Gordon Street, London, WC1H OAJ (United Kingdom); Parkin, Ivan P. [Department of Chemistry, University College London, 20 Gordon Street, London, WC1H OAJ (United Kingdom)], E-mail: i.p.parkin@ucl.ac.uk

    2008-06-02

    Atmospheric pressure chemical vapour deposition of tin monoselenide and tin diselenide films on glass substrate was achieved by reaction of diethyl selenide with tin tetrachloride at 350-650 {sup o}C. X-ray diffraction showed that all the films were crystalline and matched the reported pattern for SnSe and/or SnSe{sub 2}. Wavelength dispersive analysis by X-rays show a variable Sn:Se ratio from 1:1 to 1:2 depending on conditions. The deposition temperature, flow rates and position on the substrate determined whether mixed SnSe-SnSe{sub 2}, pure SnSe or pure SnSe{sub 2} thin films could be obtained. SnSe films were obtained at 650 {sup o}C with a SnCl{sub 4} to Et{sub 2}Se ratio greater than 10. The SnSe films were silver-black in appearance and adhesive. SnSe{sub 2} films were obtained at 600-650 {sup o}C they had a black appearance and were composed of 10 to 80 {mu}m sized adherent crystals. Films of SnSe only 100 nm thick showed complete absorbtion at 300-1100 nm.

  17. Xenon-133 and caesium-137 releases into the atmosphere from the Fukushima Dai-ichi nuclear power plant: determination of the source term, atmospheric dispersion, and deposition

    Directory of Open Access Journals (Sweden)

    A. Stohl

    2012-03-01

    Full Text Available On 11 March 2011, an earthquake occurred about 130 km off the Pacific coast of Japan's main island Honshu, followed by a large tsunami. The resulting loss of electric power at the Fukushima Dai-ichi nuclear power plant developed into a disaster causing massive release of radioactivity into the atmosphere. In this study, we determine the emissions into the atmosphere of two isotopes, the noble gas xenon-133 (133Xe and the aerosol-bound caesium-137 (137Cs, which have very different release characteristics as well as behavior in the atmosphere. To determine radionuclide emissions as a function of height and time until 20 April, we made a first guess of release rates based on fuel inventories and documented accident events at the site. This first guess was subsequently improved by inverse modeling, which combined it with the results of an atmospheric transport model, FLEXPART, and measurement data from several dozen stations in Japan, North America and other regions. We used both atmospheric activity concentration measurements as well as, for 137Cs, measurements of bulk deposition. Regarding 133Xe, we find a total release of 15.3 (uncertainty range 12.2–18.3 EBq, which is more than twice as high as the total release from Chernobyl and likely the largest radioactive noble gas release in history. The entire noble gas inventory of reactor units 1–3 was set free into the atmosphere between 11 and 15 March 2011. In fact, our release estimate is higher than the entire estimated 133Xe inventory of the Fukushima Dai-ichi nuclear power plant, which we explain with the decay of iodine-133 (half-life of 20.8 h into 133Xe. There is strong evidence that the 133Xe release started before the first active venting was made, possibly indicating structural damage to reactor components and/or leaks due to overpressure which would have allowed early release of noble gases. For 137

  18. Atmospheric Emissions and Depositions of Cadmium, Lead, and Zinc in Europe During the Period 1955-1987

    OpenAIRE

    Olendrzynski, K.; Anderberg, S.; Bartnicki, J.; PACYNA J.; Stigliani, W.M.

    1995-01-01

    This paper presents a preliminary estimate of atmospheric emissions of cadmium, lead and zinc in Europe during the period 1955-1987. The emission data are used as input to the IIASA's atmospheric transport model, TRACE m a c e toxic Air concentrations in Europe), to compute cumulative deposition loads of heavy metals onto European soils during the investigated time period. To the authors' knowledge, this is the first attempt of this kind in the open literature. The computed with the TRACE mod...

  19. In Vitro Exposures in Diesel Exhaust Atmospheres: Resuspension of PM from Filters Verses Direct Deposition of PM from Air

    Science.gov (United States)

    Lichtveld, Kim M.; Ebersviller, Seth M.; Sexton, Kenneth G.; Vizuete, William; Jaspers, Ilona; Jeffries, Harvey E.

    2012-01-01

    One of the most widely used in vitro particulate matter (PM) exposures methods is the collection of PM on filters, followed by resuspension in a liquid medium, with subsequent addition onto a cell culture. To avoid disruption of equilibria between gases and PM, we have developed a direct in vitro sampling and exposure method (DSEM) capable of PM-only exposures. We hypothesize that the separation of phases and post-treatment of filter-collected PM significantly modifies the toxicity of the PM compared to direct deposition, resulting in a distorted view of the potential PM health effects. Controlled test environments were created in a chamber that combined diesel exhaust with an urban-like mixture. The complex mixture was analyzed using both the DSEM and concurrently-collected filter samples. The DSEM showed that PM from test atmospheres produced significant inflammatory response, while the resuspension exposures at the same exposure concentration did not. Increasing the concentration of resuspended PM sixteen times was required to yield measurable IL-8 expression. Chemical analysis of the resuspended PM indicated a total absence of carbonyl compounds compared to the test atmosphere during the direct-exposures. Therefore, collection and resuspension of PM into liquid modifies its toxicity and likely leads to underestimating toxicity. PMID:22834915

  20. The Gas Nucleation Process Study of Anatase TiO2 in Atmospheric Non-Thermal Plasma Enhanced Chemical Vapor Deposition

    International Nuclear Information System (INIS)

    The gas phase nucleation process of anatase TiO2 in atmospheric non-thermal plasma enhanced chemical vapor deposition is studied. The particles synthesized in the plasma gas phase at different power density were collected outside of the reactor. The structure of the collected particles has been investigated by field scanning electron microscope (FESEM), X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED). The analysis shows that uniform crystalline nuclei with average size of several nanometers have been formed in the scale of micro second through this reactive atmospheric plasma gas process. The crystallinity of the nanoparticles increases with power density. The high density of crystalline nanonuclei in the plasma gas phase and the low gas temperature are beneficial to the fast deposition of the 3D porous anatase TiO2 film. (plasma technology)

  1. Experimentation and simulation of tin oxide deposition on glass based on the SnCl4 hydrolysis in an in-line atmospheric pressure chemical vapor deposition reactor

    International Nuclear Information System (INIS)

    Tin oxide thin films were deposited on glass substrates in an in-line atmospheric pressure chemical vapor deposition reactor under various conditions, which were numerically simulated using a commercial package. A soda-lime glass sheet was used as a deposition substrate, and SnCl4 and H2O in gas phase were separately supplied as the precursor and the oxidizer, respectively. By assuming that the main chemical reactions followed the Rideal–Eley mechanism, the experimentally determined deposition rates were fitted to obtain the reaction factors needed to describe the deposition process. The role of barrier gas injection for minimizing unwanted surface reaction or particle generation inside of the reactor, and not on the target (glass backplane itself) has been elucidated. Furthermore, the optimal operating conditions for the deposition on glass with the additives such as CH3OH and HF have been investigated. - Highlights: • Tin oxide deposition on glass based on the SnCl4 hydrolysis in an in-line reactor • Simulations using Rideal–Eley mechanism were compared to experimental observations. • Results: activation energy—79.3 kJ/mol and frequency factor—1.93 × 1010 m4/kmol·s • Influences of additives on transmittances, hazes, and electrical resistivities

  2. Ombrotrophic peat bogs are not suited as natural archives to investigate the historical atmospheric deposition of perfluoroalkyl substances.

    Science.gov (United States)

    Dreyer, Annekatrin; Thuens, Sabine; Kirchgeorg, Torben; Radke, Michael

    2012-07-17

    As ombrotrophic peat bogs receive only atmospheric input of contaminants, they have been identified as suitable natural archives for investigating historical depositions of airborne pollutants. To elucidate their suitability for determining the historical atmospheric contamination with perfluoroalkyl substances (PFAS), two peat cores were sampled at Mer Bleue, a bog located close to Ottawa, Canada. Peat cores were segmented, dried, and analyzed in duplicate for 25 PFASs (5 perfluororalkyl sulfonates (PFSAs), 13 perfluoroalkyl carboxylates (PFCAs), 7 perfluororalkyl sulfonamido substances). Peat samples were extracted by ultrasonication, cleaned up using a QuEChERS method, and PFASs were measured by HPLC-MS/MS. Twelve PFCAs and PFSAs were detected regularly in peat samples with perfluorooctane sulfonate (85-655 ng kg(-1)), perfluorooctanoate (150-390 ng kg(-1)), and perfluorononanoate (45-320 ng kg(-1)) at highest concentrations. Because of post depositional relocation processes within the peat cores, true or unbiased deposition fluxes (i.e., not affected by post depositional changes) could not be calculated. Apparent or biased deposition rates (i.e., affected by post depositional changes) were lower than measured/calculated deposition rates for similar urban or near-urban sites. Compared to PFAS production, PFAS concentration and deposition maxima were shifted about 30 years toward the past and some analytes were detected even in the oldest segments from the beginning of the 20th century. This was attributed to PFAS mobility in the peat profile. Considerable differences were observed between both peat cores and different PFASs. Overall, this study demonstrates that ombrotrophic bogs are not suited natural archives to provide authentic and reliable temporal trend data of historical atmospheric PFAS deposition. PMID:22680699

  3. Temporal and spatial variation of trace elements in atmospheric deposition around the industrial area of Puchuncaví-Ventanas (Chile) and its influence on exceedances of lead and cadmium critical loads in soils.

    Science.gov (United States)

    Rueda-Holgado, F; Calvo-Blázquez, L; Cereceda-Balic, F; Pinilla-Gil, E

    2016-02-01

    Fractionation of elemental contents in atmospheric samples is useful to evaluate pollution levels for risk assessment and pollution sources assignment. We present here the main results of long-term characterization of atmospheric deposition by using a recently developed atmospheric elemental fractionation sampler (AEFS) for major and trace elements monitoring around an important industrial complex located in Puchuncaví region (Chile). Atmospheric deposition samples were collected during two sampling campaigns (2010 and 2011) at four sampling locations: La Greda (LG), Los Maitenes (LM), Puchuncaví (PU) and Valle Alegre (VA). Sample digestion and ICP-MS gave elements deposition values (Al, As, Ba, Cd, Co, Cu, Fe, K, Mn, Pb, Sb, Ti, V and Zn) in the insoluble fraction of the total atmospheric deposition. Results showed that LG location, the closest location to the industrial complex, was the more polluted sampling site having the highest values for the analyzed elements. PU and LM were the next more polluted and, finally, the lowest elements concentrations were registered at VA. The application of Principal Component Analysis and Cluster Analysis identified industrial, traffic and mineral-crustal factors. We found critical loads exceedances for Pb at all sampling locations in the area affected by the industrial emissions, more significant in LG close to the industrial complex, with a trend to decrease in 2011, whereas no exceedances due to atmospheric deposition were detected for Cd.

  4. Spatial Variation of Atmospheric Nitrogen Deposition and Estimated Critical Loads for Aquatic Ecosystems in the Greater Yellowstone Area

    Science.gov (United States)

    Nanus, L.; McMurray, J. A.; Clow, D. W.; Saros, J. E.; Blett, T.

    2015-12-01

    Aquatic ecosystems at high-elevations in the Greater Yellowstone Area (GYA) are sensitive to the effects of atmospheric nitrogen (N) deposition. Current and historic N deposition has impacted aquatic ecosystems in the GYA and N deposition is increasing in many areas. Anticipated changes in atmospheric emissions may further affect these sensitive ecosystems. Understanding the spatial variation in atmospheric N deposition is needed to develop estimates of air pollution critical loads for aquatic ecosystems in complex terrain. For the GYA, high resolution (400 meter) maps were developed for 1993-2014 to identify areas of high loading of mean annual Total N deposition (wet + dry) and wet deposition of inorganic N (nitrate and ammonium). Total N deposition estimates in the GYA range from ≤ 1.4 to 7.5 kg N ha-1 yr-1 and show greater variability than inorganic N deposition. Spatially explicit estimates of critical loads of N deposition (CLNdep) for nutrient enrichment in aquatic ecosystems were developed using a geostatistical approach. CLNdep in the GYA ranges from less than 1.5 kg N ha-1 yr-1 to over 10 kg N ha-1 yr-1 and variability is controlled by differences in basin characteristics. The lowest CLNdep estimates occurred in high-elevation basins with steep slopes, sparse vegetation, and exposed bedrock, including areas within GYA Wilderness boundaries. These areas often have high inorganic N deposition (>3 kg N ha-1 yr-1), resulting in CLNdep exceedances greater than 1.5 kg N ha-1 yr-1. The N deposition maps were used to identify CLNdep exceedances for aquatic ecosystems, and to explore scale dependence and boundary issues related to estimating CLNdep. Based on a NO3- threshold of 1.0 μmol L-1, inorganic N deposition exceeds CLNdep in 12% of the GYA, and Total N deposition is in exceedance for 23% of the GYA. These maps can be used to help identify and protect sensitive ecosystems that may be impacted by excess N deposition in the GYA.

  5. Catchment-mediated atmospheric nitrogen deposition drives ecological change in two alpine lakes in SE Tibet.

    Science.gov (United States)

    Hu, Zhujun; Anderson, Nicholas John; Yang, Xiangdong; McGowan, Suzanne

    2014-05-01

    The south-east margin of Tibet is highly sensitive to global environmental change pressures, in particular, high contemporary reactive nitrogen (Nr) deposition rates (ca. 40 kg ha(-1)  yr(-1) ), but the extent and timescale of recent ecological change is not well prescribed. Multiproxy analyses (diatoms, pigments and geochemistry) of (210) Pb-dated sediment cores from two alpine lakes in Sichuan were used to assess whether they have undergone ecological change comparable to those in Europe and North America over the last two centuries. The study lakes have contrasting catchment-to-lake ratios and vegetation cover: Shade Co has a relatively larger catchment and denser alpine shrub than Moon Lake. Both lakes exhibited unambiguous increasing production since the late 19th to early 20th. Principle component analysis was used to summarize the trends of diatom and pigment data after the little ice age (LIA). There was strong linear change in biological proxies at both lakes, which were not consistent with regional temperature, suggesting that climate is not the primary driver of ecological change. The multiproxy analysis indicated an indirect ecological response to Nr deposition at Shade Co mediated through catchment processes since ca. 1930, while ecological change at Moon Lake started earlier (ca. 1880) and was more directly related to Nr deposition (depleted δ(15) N). The only pronounced climate effect was evidenced by changes during the LIA when photoautotrophic groups shifted dramatically at Shade Co (a 4-fold increase in lutein concentration) and planktonic diatom abundance declined at both sites because of longer ice cover. The substantial increases in aquatic production over the last ca. 100 years required a substantial nutrient subsidy and the geochemical data point to a major role for Nr deposition although dust cannot be excluded. The study also highlights the importance of lake and catchment morphology for determining the response of alpine lakes to

  6. A quality-assurance assessment for constituents reported by the National Atmospheric Deposition Program and the National Trends Network

    Science.gov (United States)

    See, R.B.; Schroder, L.J.; Willoughby, T.C.

    1989-01-01

    A continuing quality-assurance program has been operated by the U.S. Geographical Survey to evaluate any bias introduced by routine handling, shipping, and laboratory analyses of wet-deposition samples collected in the National Atmospheric Deposition Program (NADP) and National Trends Network (NTN). Blind-audit samples having a variety of constituent concentrations and values were selected. Only blind-audit samples with constituent concentrations and values less than the 95th-percentile concentration for natural wet-deposition samples were included in the analysis. Of the major ions, there was a significant increase of Ca2+, Mg2+, K+ SO42+ and Cl- in samples handled according to standard protocols and shipped in NADP/NTN sample-collection buckets. For 1979-1987, graphs of smoothed data showing the estimated contaminations in blind-audit samples indicate a decrease in the median concentration and ranges of Ca2+, Mg2+ and SO42- contamination of blind-audit samples shipped in sample-collection buckets. Part of the contamination detected in blind-audit samples can be attributed to contact with the sample-collection bucket and lid; however, additional sources also seem to contaminate the blind-audit sample. Apparent decreases in the magnitude and range of sample contamination may be caused by differences in sample-collection bucket- and lid-washing procedures by the NADP/NTN Central Analytical Laboratory. Although the degree of bias is minimal for most constituents, summaries of the NADP/NTN data base may contain overestimates of Ca2+, Mg2+, Na-, K+, SO42- and Cl- concentrations, and underestimates of H+ concentrations.

  7. Atmospheric total gaseous mercury (TGM) concentrations and wet and dry deposition of mercury at a high-altitude mountain peak in south China

    OpenAIRE

    Zhang, H.; Yang, Z. R.; Wang, J. X.; R. S. Yin; Dong, Z. Q.; Feng, X.; X. W. Fu

    2009-01-01

    China is regarded as the largest contributor of mercury (Hg) to the global atmospheric Hg budget. However, concentration levels and depositions of atmospheric Hg in China are poorly known. Continuous measurements of atmospheric total gaseous mercury (TGM) were carried out from May 2008 to May 2009 at the summit of Mt. Leigong in south China. Wet and dry deposition fluxes of Hg were also calculated following collection of precipitation, throughfall and litterfall. Atmospheric TGM concentration...

  8. Methods, quality assurance, and data for assessing atmospheric deposition of pesticides in the Central Valley of California

    Science.gov (United States)

    Zamora, Celia; Majewski, Michael S.; Foreman, William T.

    2013-01-01

    The U.S. Geological Survey monitored atmospheric deposition of pesticides in the Central Valley of California during two studies in 2001 and 2002–04. The 2001 study sampled wet deposition (rain) and storm-drain runoff in the Modesto, California, area during the orchard dormant-spray season to examine the contribution of pesticide concentrations to storm runoff from rainfall. In the 2002–04 study, the number and extent of collection sites in the Central Valley were increased to determine the areal distribution of organophosphate insecticides and other pesticides, and also five more sample types were collected. These were dry deposition, bulk deposition, and three sample types collected from a soil box: aqueous phase in runoff, suspended sediment in runoff, and surficial-soil samples. This report provides concentration data and describes methods and quality assurance of sample collection and laboratory analysis for pesticide compounds in all samples collected from 16 sites. Each sample was analyzed for 41 currently used pesticides and 23 pesticide degradates, including oxygen analogs (oxons) of 9 organophosphate insecticides. Analytical results are presented by sample type and study period. The median concentrations of both chloryprifos and diazinon sampled at four urban (0.067 micrograms per liter [μg/L] and 0.515 μg/L, respectively) and four agricultural sites (0.079 μg/L and 0.583 μg/L, respectively) during a January 2001 storm event in and around Modesto, Calif., were nearly identical, indicating that the overall atmospheric burden in the region appeared to be fairly similar during the sampling event. Comparisons of median concentrations in the rainfall to those in the McHenry storm-drain runoff showed that, for some compounds, rainfall contributed a substantial percentage of the concentration in the runoff; for other compounds, the concentrations in rainfall were much greater than in the runoff. For example, diazinon concentrations in rainfall were about

  9. A kinetic and equilibrium analysis of silicon carbide chemical vapor deposition on monofilaments

    Science.gov (United States)

    Gokoglu, S. A.; Kuczmarski, M. A.

    1993-01-01

    Chemical kinetics of atmospheric pressure silicon carbide (SiC) chemical vapor deposition (CVD) from dilute silane and propane source gases in hydrogen is numerically analyzed in a cylindrical upflow reactor designed for CVD on monofilaments. The chemical composition of the SiC deposit is assessed both from the calculated total fluxes of carbon and silicon and from chemical equilibrium considerations for the prevailing temperatures and species concentrations at and along the filament surface. The effects of gas and surface chemistry on the evolution of major gas phase species are considered in the analysis.

  10. Atmospheric gas-particle partitioning versus gaseous/particle-bound deposition of SVOCs: Why they are not equivalent

    Science.gov (United States)

    Glüge, Juliane; Bogdal, Christian; Scheringer, Martin; Hungerbühler, Konrad

    2015-08-01

    Semi-volatile organic compounds (SVOCs) can be particle-bound or in the gas phase in the atmosphere, depending on the (temperature dependent) gas-particle partitioning of the chemicals and the fraction of particles in air. Several studies linked gas-particle partitioning of SVOCs in the atmosphere directly to the gaseous/particle-bound deposition of these chemicals, i.e. in cases of compounds occurring mainly in the gas phase, the deposition was also assumed to be mainly in gaseous form. In this study, we apply a multi-media fate model to point out that gas-particle partitioning of SVOCs in air and gaseous/particle-bound deposition of SVOCs are driven by different mechanism and, thus, cannot be deduced from each other. We apply our calculations to polychlorinated biphenyls (PCBs), as model SVOCs. We show that the fraction of particle-bound deposition to deciduous forest is 1.5-190 times higher in winter and between 5 and 1000 times higher in summer than the particle-bound fraction of these chemicals in air. The fraction of particle-bound deposition to coniferous forest is 1.5-172 times higher in winter and between 5 and 1000 times higher in summer than the particle-bound fraction of PCBs in air. In addition to the fractions of particle-bound SVOCs in air and particle-bound deposition, we recalculated particle-bound and gaseous deposition velocities to coniferous and deciduous forest for PCBs. The deposition velocities obtained for dry gaseous deposition (PCBs occurring predominantly in the gas phase, interception was also completely due to dry gaseous deposition.

  11. Atmospheric Ionic Deposition in Tropical Sites of Central Sulawesi Determined by Ion Exchange Resin Collectors and Bulk Water Collector.

    Science.gov (United States)

    Köhler, S; Jungkunst, H F; Gutzler, C; Herrera, R; Gerold, G

    2012-09-01

    In the light of global change, the necessity to monitor atmospheric depositions that have relevant effects on ecosystems is ever increasing particularly for tropical sites. For this study, atmospheric ionic depositions were measured on tropical Central Sulawesi at remote sites with both a conventional bulk water collector system (BWS collector) and with a passive ion exchange resin collector system (IER collector). The principle of IER collector to fix all ionic depositions, i.e. anions and cations, has certain advantages referring to (1) post-deposition transformation processes, (2) low ionic concentrations and (3) low rainfall and associated particulate inputs, e.g. dust or sand. The ionic concentrations to be measured for BWS collectors may easily fall below detection limits under low deposition conditions which are common for tropical sites of low land use intensity. Additionally, BWS collections are not as independent from the amount of rain fallen as are IER collections. For this study, the significant differences between both collectors found for nearly all measured elements were partly correlated to the rainfall pattern, i.e. for calcium, magnesium, potassium and sodium. However, the significant differences were, in most cases, not highly relevant. More relevant differences between the systems were found for aluminium and nitrate (434-484 %). Almost five times higher values for nitrate clarified the advantage of the IER system particularly for low deposition rate which is one particularity of atmospheric ionic deposition in tropical sites of extensive land use. The monthly resolution of the IER data offers new insights into the temporal distribution of annual ionic depositions. Here, it did not follow the tropical rain pattern of a drier season within generally wet conditions.

  12. Atmospheric Ionic Deposition in Tropical Sites of Central Sulawesi Determined by Ion Exchange Resin Collectors and Bulk Water Collector.

    Science.gov (United States)

    Köhler, S; Jungkunst, H F; Gutzler, C; Herrera, R; Gerold, G

    2012-09-01

    In the light of global change, the necessity to monitor atmospheric depositions that have relevant effects on ecosystems is ever increasing particularly for tropical sites. For this study, atmospheric ionic depositions were measured on tropical Central Sulawesi at remote sites with both a conventional bulk water collector system (BWS collector) and with a passive ion exchange resin collector system (IER collector). The principle of IER collector to fix all ionic depositions, i.e. anions and cations, has certain advantages referring to (1) post-deposition transformation processes, (2) low ionic concentrations and (3) low rainfall and associated particulate inputs, e.g. dust or sand. The ionic concentrations to be measured for BWS collectors may easily fall below detection limits under low deposition conditions which are common for tropical sites of low land use intensity. Additionally, BWS collections are not as independent from the amount of rain fallen as are IER collections. For this study, the significant differences between both collectors found for nearly all measured elements were partly correlated to the rainfall pattern, i.e. for calcium, magnesium, potassium and sodium. However, the significant differences were, in most cases, not highly relevant. More relevant differences between the systems were found for aluminium and nitrate (434-484 %). Almost five times higher values for nitrate clarified the advantage of the IER system particularly for low deposition rate which is one particularity of atmospheric ionic deposition in tropical sites of extensive land use. The monthly resolution of the IER data offers new insights into the temporal distribution of annual ionic depositions. Here, it did not follow the tropical rain pattern of a drier season within generally wet conditions. PMID:22865942

  13. Characteristics of SiOX thin films deposited by atmospheric pressure chemical vapor deposition using a double-discharge system

    International Nuclear Information System (INIS)

    SiOX thin films were deposited using a gas mixture of hexamethyldisilazane (HMDS)/O2/He/Ar from a remote-type dielectric barrier discharges (DBD) source, with/without the additional direct-type DBD just above the substrate (double discharge), and the effect of the double discharge on the characteristics of the SiOX thin film was investigated. The increase of HMDS flow rate and the decrease of oxygen flow rate in the gas mixture increased the SiOX-thin-film deposition rate. The improvement of the mechanical properties for SiOX film, in addition to the increase of deposition rate, is believed to be related not only to the higher gas dissociation because of the higher power deposition but also to the lesser recombination of oxygen atoms and dissociated HMDS due to the shorter diffusion length to the substrate.

  14. Atmospheric deposition of trace elements around point sources and human health risk assessment. II: Uptake of arsenic and chromium by vegetables grown near a wood preservation factory

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Moseholm, Lars; Nielsen, Margot M.

    1992-01-01

    Kale, lettuce, carrots and potatoes were grown in 20 experimental plots surrounding a wood preservation factory, to investigate the amount and pathways for plant uptake of arsenic and chromium. Arsenate used in the wood preservation process is converted to the more toxic arsenite by incineration...... of waste wood and is emitted into the atmosphere. Elevated concentrations of inorganic arsenic and chromium were found both in the test plants and in the soil around the factory. Multivariate statistical analysis of the results indicated that the dominating pathway of arsenic and chromium from the factory...... to the leafy vegetables grown nearby was by direct atmospheric deposition, while arsenic in the root crops originated from both the soil and the atmosphere. Consumption of vegetables grown near the source would result in an increased intake of inorganic arsenic, but the intake via the total diet was estimated...

  15. First survey of atmospheric heavy metal deposition in Kosovo using moss biomonitoring.

    Science.gov (United States)

    Maxhuni, Albert; Lazo, Pranvera; Kane, Sonila; Qarri, Flora; Marku, Elda; Harmens, Harry

    2016-01-01

    Bryophytes act as bioindicators and bioaccumulators of metal deposition in the environment. The atmospheric deposition of Cd, Cr, Cu, Fe, Hg, Ni, Mn, Pb, and Zn in Kosovo was investigated by using carpet-forming moss species (Pseudocleropodium purum and Hypnum cupressiforme) as bioindicators. This research is part of the European moss survey coordinated by the ICP Vegetation, an International Cooperative Programme reporting on the effects of air pollution on vegetation to the UNECE Convention on Long-range Transboundary Air Pollution. Sampling was performed during the summer of 2011 at 25 sampling sites homogenously distributed over Kosovo. Unwashed, dried samples were digested by using wet digestion in Teflon tubes. The concentrations of metal elements were determined by atomic absorption spectrometry (AAS) equipped with flame and/or furnace systems. The heavy metal concentration in mosses reflected local emission sources. The data obtained in this study were compared with those of similar studies in neighboring countries and Europe (2010-2014 survey). The geographical distribution maps of the elements over the sampled territory were constructed using geographic information system (GIS) technology. The concentrations of Cr, Ni, Pb, and Zn were higher than the respective median values of Europe, suggesting that the zones with heavy vehicular traffic and industry emission input are important emitters of these elements. Selected zones are highly polluted particularly by Cd, Pb, Hg, and Ni. The statistical analyses revealed that a strong correlation exists between the Pb and Cd content in mosses, and the degree of pollution in the studied sites was assessed. PMID:26336845

  16. Reconstructing historical atmospheric mercury deposition in Western Europe using: Misten peat bog cores, Belgium

    Energy Technology Data Exchange (ETDEWEB)

    Allan, Mohammed, E-mail: mallan@doct.ulg.ac.be [Argiles, Geochimie et Environnement sedimentaires, Departement de Geologie, Universite de Liege, Allee du 6 Aout B18 Sart Tilman B4000-Liege (Belgium); Le Roux, Gael [Universite de Toulouse, INP, UPS, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), ENSAT, Avenue de l' Agrobiopole, 31326 Castanet Tolosan (France); CNRS, EcoLab, 31326 Castanet Tolosan (France); Sonke, Jeroen E. [Geosciences Environnement Toulouse, CNRS/IRD/Universite de Toulouse 3, 14 avenue Edouard Belin, 31400 Toulouse (France); Piotrowska, Natalia [Department of Radioisotopes, GADAM Centre of Excellence, Institute of Physics, Silesian University of Technology, Gliwice (Poland); Streel, Maurice [PPM, Departement de Geologie, Universite de Liege, Allee du 6 Aout B18 Sart Tilman B4000-Liege (Belgium); Fagel, Nathalie [Argiles, Geochimie et Environnement sedimentaires, Departement de Geologie, Universite de Liege, Allee du 6 Aout B18 Sart Tilman B4000-Liege (Belgium)

    2013-01-01

    Four sediment cores were collected in 2008 from the Misten ombrotrophic peat bog in the Northern part of the Hautes Fagnes Plateau in Belgium. Total mercury (Hg) concentrations were analyzed to investigate the intra-site variability in atmospheric Hg deposition over the past 1500 years. Mercury concentrations in the four cores ranged from 16 to 1100 {mu}g kg{sup -1}, with the maxima between 840 and 1100 {mu}g kg{sup -1}. A chronological framework was established using radiometric {sup 210}Pb and {sup 14}C dating of two cores (M1 and M4). Pollen horizons from these two cores were correlated with data from two additional cores, providing a consistent dating framework between all the sites. There was good agreement between atmospheric Hg accumulation rates in the four cores over time based on precise age dating and pollen chronosequences. The average Hg accumulation rate before the influence of human activities (from 500 to 1300 AD) was 1.8 {+-} 1 {mu}g m{sup -2} y{sup -1} (2SD). Maximum Hg accumulation rates ranged from 90 to 200 {mu}g m{sup -2} y{sup -1} between 1930 and 1980 AD. During the European-North American Industrial Revolution, the mean Hg accumulation rate exceeded the pre-Industrial values by a factor of 63. Based on comparisons with historical records of anthropogenic activities in Europe and Belgium, the predominant regional anthropogenic sources of Hg during and after the Industrial Revolution were coal burning and smelter Hg emissions. Mercury accumulation rates and chronologies in the Misten cores were consistent with those reported for other European peat records. -- Highlights: Black-Right-Pointing-Pointer Study of Hg concentration in four cores from Belgian peat bog. Black-Right-Pointing-Pointer Reconstruction of Hg deposition over last 1500 years. Black-Right-Pointing-Pointer Maximum Hg accumulation rates ranging from 90 to 200 {mu}g m{sup -2} y{sup -1} are recorded between 1930 and 1980 AD. Black-Right-Pointing-Pointer The average Hg

  17. Reconstructing historical atmospheric mercury deposition in Western Europe using: Misten peat bog cores, Belgium

    International Nuclear Information System (INIS)

    Four sediment cores were collected in 2008 from the Misten ombrotrophic peat bog in the Northern part of the Hautes Fagnes Plateau in Belgium. Total mercury (Hg) concentrations were analyzed to investigate the intra-site variability in atmospheric Hg deposition over the past 1500 years. Mercury concentrations in the four cores ranged from 16 to 1100 μg kg−1, with the maxima between 840 and 1100 μg kg−1. A chronological framework was established using radiometric 210Pb and 14C dating of two cores (M1 and M4). Pollen horizons from these two cores were correlated with data from two additional cores, providing a consistent dating framework between all the sites. There was good agreement between atmospheric Hg accumulation rates in the four cores over time based on precise age dating and pollen chronosequences. The average Hg accumulation rate before the influence of human activities (from 500 to 1300 AD) was 1.8 ± 1 μg m−2 y−1 (2SD). Maximum Hg accumulation rates ranged from 90 to 200 μg m−2 y−1 between 1930 and 1980 AD. During the European–North American Industrial Revolution, the mean Hg accumulation rate exceeded the pre-Industrial values by a factor of 63. Based on comparisons with historical records of anthropogenic activities in Europe and Belgium, the predominant regional anthropogenic sources of Hg during and after the Industrial Revolution were coal burning and smelter Hg emissions. Mercury accumulation rates and chronologies in the Misten cores were consistent with those reported for other European peat records. -- Highlights: ► Study of Hg concentration in four cores from Belgian peat bog. ► Reconstruction of Hg deposition over last 1500 years. ► Maximum Hg accumulation rates ranging from 90 to 200 μg m−2 y−1 are recorded between 1930 and 1980 AD. ► The average Hg accumulation rate before the influence of human activities (e.g. 1300 AD) was 1.8 ± 1 μg m−2 y−1. ► The predominant anthropogenic Hg sources were coal

  18. Alpine Microbial Community Responses to Climate Change and Atmospheric Nitrogen Deposition in Rocky Mountain National Park

    Science.gov (United States)

    Osborne, B. B.; Baron, J.; Wallenstein, M. D.; Richer, E.

    2010-12-01

    Remote alpine ecosystems of the western US exhibit vulnerability to anthropogenic drivers of change. Atmospheric nitrogen (N) deposition and a changing climate introduce nutrients, alter hydrological processes, and expose soils to modified temperature regimes. We cannot yet predict the interacting effects and far-reaching biogeochemical consequences of this influence. Importantly, long-term data reveal headwater nitrate (NO3-) concentration trends increasing >50% from the 1990s to 2006 along the Colorado Front Range in conjunction with warm summer temperatures. Such a change in nutrient cycling raises concern for eutrophication in nutrient-poor alpine lakes. Increasing stream NO3- suggests terrestrial microbes may be responding to changes in important controls of community development and activity: temperature and ammonium (NH4+) availability. Nitrifying bacteria and archaea strongly influence alpine soil NO3- concentrations. Little is understood about alpine microbes. Our research characterizes nitrifier abundance and activity in alpine substrates by exposing them to experimental NH4+ and temperature treatments. Soil substrates fall along a gradient of succession commonly represented in alpine catchments due to deglaciation. These include well-developed meadow soils, unvegetated talus substrate, and newly-exposed glacial sediments. All three substrate types were collected from the Loch Vale watershed in Rocky Mountain National Park, a long-term research site in the Colorado Front Range known to receive elevated levels of atmospheric N deposition. All soils have been evaluated for initial %C, %N, microbial biomass, NO3-, NH4+, and DOC concentrations, and nitrifier abundance. After temperature and NH4+ treatments, samples will be evaluated for changes in biomass and nitrifier abundance as well as net and gross nitrification. Linking the influence of relative soil temperature and NH4+ concentrations on alpine substrates, at a range of successional stages, will

  19. Long-Term Measurments of Atmospheric Mercury Species (TGM, TPM and Hg Deposition in the Silesian Region, Poland – Concept of the Mercury Deposition Coefficient

    Directory of Open Access Journals (Sweden)

    Nowak Bartosz

    2014-12-01

    Full Text Available The aim of this work was to identify concentration levels of different chemical forms of mercury (TGM, TPM in the ambient air in selected areas of the Silesian Region, characterized by low and high mercury emission. Based on the obtained data TGM and TPM concentration levels were determined. The project also focused on determination of dry and wet deposition of mercury compounds. Data concerning TGM and TPM flux rates in the ambient air and data on mercury deposition were used to determine a deposition coefficient. The coefficient was calculated as a share of mercury deposition on the land surface (dry and wet to the amount of this contaminant transported with loads of air in the form of TGM and TPM in a given measurement station. At both monitoring stations the deposition coefficient did not exceed 0.2 %. The idea of calculating the deposition coefficient based on the analysis of TGM and TPM flux rate is a new solution. The proposed deposition coefficient allows to quantify information on a selected contaminant concentration and its potential impact resulting from deposition. Further studies on the deposition coefficient may contribute to the development of methods for estimating the impact of contaminants contained in the ambient air on other environmental components based on the analyses of the contaminant flux rate.

  20. Use of the lichen Xanthoria mandschurica in monitoring atmospheric elemental deposition in the Taihang Mountains, Hebei, China.

    Science.gov (United States)

    Liu, Hua-Jie; Zhao, Liang-Cheng; Fang, Shi-Bo; Liu, Si-Wa; Hu, Jian-Sen; Wang, Lei; Liu, Xiao-Di; Wu, Qing-Feng

    2016-01-01

    Air pollution is a major concern in China. Lichens are a useful biomonitor for atmospheric elemental deposition but have rarely been used in North China. The aim of this study was to investigate the atmospheric depositions of 30 trace elements (Al, Ba, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, Sb, Sc, Sm, Sr, Tb, Th, Ti, Tl, V and Zn) in a region of the Taihang Mountains, Hebei Province, China using lichens as biomonitors. Epilithic foliose lichen Xanthoria mandschurica was sampled from 21 sites and analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The results show that 1) eight elements (Cd, Cr, Cu, Mo, P, Pb, Sb and Zn) are of atmospheric origin and are highly influenced by the atmospheric transportation from the North China Plain, as well as local mining activities, while 2) the remaining 22 elements are primarily of crustal origin, the concentration of which has been enhanced by local mining and quarrying activities. These results clearly validate the applicability of lichens in biomonitoring of atmospheric elemental deposition and demonstrate the spatial pattern for air pollution in the region. PMID:27089945

  1. Effects of wet deposition on optical properties of the atmosphere over Bermuda and Barbados

    Science.gov (United States)

    Todd, Deborah L.; Keene, William C.; Moody, Jennie L.; Maring, Hal; Galloway, James N.

    2003-02-01

    Substantial spatial and temporal variabilities in chemical and physical properties of aerosols complicate attempts to model associated influences on global climate. Although wet deposition is the major mechanism by which most aerosols are removed from the atmosphere, direct effects of precipitation on radiative properties of the atmosphere are not well understood. To address this issue, attenuation coefficients for total insoluble constituents (ACt) and for nonvolatile (at 500°C) insoluble constituents (ACnv; primarily crustal dust) of precipitation at Bermuda and Barbados were measured at six wavelengths between 414 and 859 nm. Coefficients for volatile (at 500°C) insoluble constituents (ACv; primarily carbonaceous species) were calculated by difference. Between April and September, ACt at Bermuda was dominated by mineral constituents transported from North Africa, whereas carbonaceous species from North America were relatively low and exhibited no systematic seasonal variability. ACt and ACnv at Barbados were dominated by mineral dust, especially between April and September. Relative to ACv, ACnv decreased more rapidly with increasing wavelength. The wavelength dependencies of ACs for volatile and nonvolatile constituents at Bermuda were statistically indistinguishable from those at Barbados. The optical and chemical characteristics of precipitation were compared with scattering and absorption by ambient aerosols in associated air parcels to evaluate the influence of scavenging on the radiative properties of air. Although discernible relationships were evident, the small number of cases limited their applicability as reliable empirical predictors. However, these data do provide useful constraints for validating models of aerosol scavenging and wet removal on the optical properties of the troposphere.

  2. Precision and bias of selected analytes reported by the National Atmospheric Deposition Program and National Trends Network, 1983; and January 1980 through September 1984

    Science.gov (United States)

    Schroder, L.J.; Bricker, A.W.; Willoughby, T.C.

    1985-01-01

    Blind-audit samples with known analyte concentrations have been prepared by the U.S. Geological Survey and distributed to the National Atmospheric Deposition Program 's Central Analytical Laboratory. The difference between the National Atmospheric Deposition Program and National Trends Network reported analyte concentrations and known analyte concentrations have been calculated, and the bias has been determined. Calcium, magnesium , sodium, and chloride were biased at the 99-percent confidence limit; potassium and sulfate were unbiased at the 99-percent confidence limit, for 1983 results. Relative-percent differences between the measured and known analyte concentration for calcium , magnesium, sodium, potassium, chloride, and sulfate have been calculated for 1983. The median relative percent difference for calcium was 17.0; magnesium was 6.4; sodium was 10.8; potassium was 6.4; chloride was 17.2; and sulfate was -5.3. These relative percent differences should be used to correct the 1983 data before user-analysis of the data. Variances have been calculated for calcium, magnesium, sodium, potassium, chloride, and sulfate determinations. These variances should be applicable to natural-sample analyte concentrations reported by the National Atmospheric Deposition Program and National Trends Network for calendar year 1983. (USGS)

  3. The effect of deposition atmosphere on the chemical composition of TiN and ZrN thin films grown by pulsed laser deposition

    International Nuclear Information System (INIS)

    Very thin TiN and ZrN films (4 or N2. Auger electron spectroscopy investigations found that films contained a relatively low oxygen concentration, usually below 3.0 at%. Films deposited under residual vacuum or very low N2 pressures (−3 Pa) contained 3–6 at% C atoms in the bulk. This fraction grew to 8–10 at% when the deposition was performed under an atmosphere of 2 × 10−3 Pa CH4. To avoid C atoms incorporation into the bulk a deposition pressure of 10 Pa N2 was required. X-ray photoelectron spectroscopy investigations found that oxygen was mostly bonded in an oxynitride type of compound, while carbon was bonded into a metallic carbide. The presence of C atoms in the chemical composition of the TiN or ZrN improved the measured hardness of the films.

  4. ENVIRONMENTAL MONITORING USING LINDEN TREE LEAVES AS NATURAL TRAPS OF ATMOSPHERIC DEPOSITION: A PILOT STUDY IN TRANSILVANIA, ROMANIA

    Directory of Open Access Journals (Sweden)

    MIHÁLY BRAUN

    2007-12-01

    Full Text Available Atmospheric pollution caused by toxic elements is an emerging problem of concern. Tree leaves have been widely used as indicator of atmospheric pollutions and they are effective alternatives to the moreusual biomonitoring methods. Tree leaves can be used as natural traps of atmospheric deposition. Elemental composition of dust deposited onto leaf surfaces can be used to characterize the urban environment. A pilot survey including 16 Romanian settlements was carried out in order to evaluate the characteristics and sources of air pollutants. Tree leaves (Tilia tomentosa, Tilia cordata, Tilia platyphyllos were collected and used for the measurements. Elemental analyses were carried out by ICP-OES and ICP-MS. Principal component and discriminant analyses were used to characterizing and estimating the level of pollution. Settlements were grouped on the basis of discriminant function values. Multivariate comparison of chemical data ordered the settlements into 3 main groups, which showed a systematic geographic distribution.

  5. On-line coating of glass with tin oxide by atmospheric pressure chemical vapor deposition.

    Energy Technology Data Exchange (ETDEWEB)

    Allendorf, Mark D.; Sopko, J.F. (PPF Industries, Pittsburgh, PA); Houf, William G.; Chae, Yong Kee; McDaniel, Anthony H.; Li, M. (PPF Industries, Pittsburgh, PA); McCamy, J.W. (PPF Industries, Pittsburgh, PA)

    2006-11-01

    Atmospheric pressure chemical vapor deposition (APCVD) of tin oxide is a very important manufacturing technique used in the production of low-emissivity glass. It is also the primary method used to provide wear-resistant coatings on glass containers. The complexity of these systems, which involve chemical reactions in both the gas phase and on the deposition surface, as well as complex fluid dynamics, makes process optimization and design of new coating reactors a very difficult task. In 2001 the U.S. Dept. of Energy Industrial Technologies Program Glass Industry of the Future Team funded a project to address the need for more accurate data concerning the tin oxide APCVD process. This report presents a case study of on-line APCVD using organometallic precursors, which are the primary reactants used in industrial coating processes. Research staff at Sandia National Laboratories in Livermore, CA, and the PPG Industries Glass Technology Center in Pittsburgh, PA collaborated to produce this work. In this report, we describe a detailed investigation of the factors controlling the growth of tin oxide films. The report begins with a discussion of the basic elements of the deposition chemistry, including gas-phase thermochemistry of tin species and mechanisms of chemical reactions involved in the decomposition of tin precursors. These results provide the basis for experimental investigations in which tin oxide growth rates were measured as a function of all major process variables. The experiments focused on growth from monobutyltintrichloride (MBTC) since this is one of the two primary precursors used industrially. There are almost no reliable growth-rate data available for this precursor. Robust models describing the growth rate as a function of these variables are derived from modeling of these data. Finally, the results are used to conduct computational fluid dynamic simulations of both pilot- and full-scale coating reactors. As a result, general conclusions are

  6. Variations of weekly atmospheric deposition for multiple collectors at a site on the shore of Lake Okeechobee, Florida

    Science.gov (United States)

    Peters, N.E.; Reese, R.S.

    1995-01-01

    Eight wet/dry precipitation collectors were modified to house four additional dryfall collectors and one bulk precipitation collector to sample atmospheric deposition for 12 weeks in a small area on the southwestern shore of Lake Okeechobee; sample contamination, primarily by insects, reduced the comparison to the last nine weeks. The deposition was determined for Ca2+, Na+, Cl-, and SO42- and nutrients including total phosphorus, orthophosphate, total ammonia plus organic nitrogen, and nitrite plus nitrate. In general, deposition was lower and less variable in wet precipitation than in bulk precipitation. The higher variability of the bulk precipitation was attributed to local contamination, particularly by dust and insects. Each wet/dry precipitation collector was fitted with dryfall collectors that consisted of the dry-side bucket on a wet/dry collector, which was preloaded with distilled and deionized water, and four glass dish collectors; two of the glass dishes were preloaded with water and the other two remained dry. The deposition to the dry dish collectors was not comparable in adjacent collectors for any constituent; however, the deposition in the adjacent water-loaded dishes was comparable for most major constituents, except nutrients. A comparison of Ortho-P deposition with Total-P indicated that the P collected by the dryfall collectors was predominantly reactive, which also was reflected in the bulk deposition, whereas that in the wet deposition was mostly nonreactive. The large variability in deposition of P among the bulk and dryfall collectors suggests that alternative methods must be used to evaluate the P sources and processes of atmospheric transfer.

  7. Modelling of wet deposition of atmospheric polycyclic aromatic hydrocarbons by the consecutive measurements in an urban area, Japan.

    Science.gov (United States)

    Kojima, Keisuke; Kobayashi, Shinji; Kindaichi, Tomonori; Ozaki, Noriatsu

    2010-01-01

    The wet deposition for particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) was modelled from the consecutive measurements of atmospheric concentration and wet deposition for particulate matter and PAHs in Higashi-Hiroshima city, Japan. In order to estimate the model in detail, the wet deposition was classified with that from gaseous and PM phase. The gaseous PAHs assumed to be dissolved into raindrops according to Henry's constant, and the PAHs attached on atmospheric PM were assumed to be trapped with PM. The PM was classified with coarse (>7 μm) and fine (0.6-7 μm) PM for the calculation of trap. PM and PAHs depositions estimated with the wet deposition model were compared with measured data. The ratios of the measured to the estimated values of PM and PAHs gave close agreement with measurements (0.41-4.29 (1.35: average) for PM and (0.32-3.83 (1.42)) for PAHs) regardless of precipitation. The depositions of PAHs of liquid and particulate phase were on the other hand significantly different from those from g