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Sample records for national atmospheric deposition

  1. Influence of atmospheric deposition on Okefenokee National Wildlife Refuge

    SciTech Connect

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

    1995-12-31

    Designation of Okefenokee National Wildlife Refuge (Georgia) as a Class 1 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 concentrations of 9 ng/L and 0.1 ng/L, respectively. Surface waters were acidic (pH 4.7--4.9), with average total and methyl mercury 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--16ng/g. Lead was 0--1.7 {micro}g/L in rainfall, not detectable in surface water, 3.4--5.4 {micro}g/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.

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

    USGS Publications Warehouse

    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.

  3. Evaluation of bias in wet deposition data from the National Atmospheric Deposition Program/National Trends Network (NADP/NTN)

    SciTech Connect

    Bowersox, V.C.; Stensland, G.J.; Peden, M.E. )

    1987-01-01

    Wet deposition data spanning the years from 1978 to 1986 are now available in National Atmospheric Deposition Program/National Trends Network (NADP/NTN) data reports and summaries. This information is complemented by quality assurance summaries that report various measurements of bias and precision or that address possible sources of sampling bias in the NADP/NTN data. Measurements of bias that accrue from the sampling container, a plastic (LPE) bucket; fugitive dust that enters the bucket while it is installed in the collector; laboratory handing of the sample; and analytical measurement of the sample have been reported. By integrating data from these various sources, this paper evaluates bias in the measurement system and thus a lower limit to which NADP/NTN data can be quantified.

  4. The precision of wet atmospheric deposition data from national atmospheric deposition program/national trends network sites determined with collocated samplers

    USGS Publications Warehouse

    Nilles, M.A.; Gordon, J.D.; Schroder, L.J.

    1994-01-01

    A collocated, wet-deposition sampler program has been operated since October 1988 by the U.S. Geological Survey to estimate the overall sampling precision of wet atmospheric deposition data collected at selected sites in the National Atmospheric Deposition Program and National Trends Network (NADP/NTN). A duplicate set of wet-deposition sampling instruments was installed adjacent to existing sampling instruments at four different NADP/NTN sites for each year of the study. Wet-deposition samples from collocated sites were collected and analysed using standard NADP/NTN procedures. Laboratory analyses included determinations of pH, specific conductance, and concentrations of major cations and anions. The estimates of precision included all variability in the data-collection system, from the point of sample collection through storage in the NADP/NTN database. Sampling precision was determined from the absolute value of differences in the analytical results for the paired samples in terms of median relative and absolute difference. The median relative difference for Mg2+, Na+, K+ and NH4+ concentration and deposition was quite variable between sites and exceeded 10% at most sites. Relative error for analytes whose concentrations typically approached laboratory method detection limits were greater than for analytes that did not typically approach detection limits. The median relative difference for SO42- and NO3- concentration, specific conductance, and sample volume at all sites was less than 7%. Precision for H+ concentration and deposition ranged from less than 10% at sites with typically high levels of H+ concentration to greater than 30% at sites with low H+ concentration. Median difference for analyte concentration and deposition was typically 1.5-2-times greater for samples collected during the winter than during other seasons at two northern sites. Likewise, the median relative difference in sample volume for winter samples was more than double the annual median

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

    USGS Publications Warehouse

    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

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

    USGS Publications Warehouse

    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.

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

    USGS Publications Warehouse

    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

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

    PubMed

    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.

  9. National Atmospheric Deposition Program (NADP) Networks: Data on the chemistry of precipitation

    DOE Data Explorer

    The National Atmospheric Deposition Program/National Trends Network (NADP/NTN) is a nationwide network of sites collecting data on the chemistry of precipitation for monitoring of geographical and temporal long-term trends. The precipitation at each station is collected weekly according to strict clean-handling procedures. It is then sent to the Central Analytical Laboratory where it is analyzed for hydrogen (acidity as pH), sulfate, nitrate, ammonium, chloride, and base cations (such as calcium, magnesium, potassium and sodium). The network is a cooperative effort between many different groups, including the State Agricultural Experiment Stations, U.S. Geological Survey, U.S. Department of Agriculture, and numerous other governmental and private entities. DOE is one of these cooperating agencies, though it plays a smaller funding role than some of the other federal sources. Since 1978, the NADP/NTN has grown from 22 stations to over 250 sites spanning the continental United States, Alaska, and Puerto Rico, and the Virgin Islands. The National Atmospheric Deposition Program has also expanded its sampling to two additional networks: 1) the Mercury Deposition Network (MDN), currently with over 90 sites, was formed in 1995 to collect weekly samples of precipitation which are analyzed by Frontier Geosciences for total mercury, and 2) the Atmospheric Integrated Research Monitoring Network (AIRMoN), formed for the purpose of studying precipitation chemistry trends with greater temporal resolution than the NTN. [taken from the NADP History and Overview page at http://nadp.sws.uiuc.edu/nadpoverview.asp] Data from these networks are freely available in via customized search interfaces linked to interactive maps of the stations in the three networks. Animated Isopleth maps in Flash and PowerPoint are also available to display concentrations and depositions various substances such as sulfate, nitrate, etc. (Specialized Interface)

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

    USGS Publications Warehouse

    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.

  11. Monitoring Atmospheric Deposition of Nitrogen in Alpine Environments in Rocky Mountain and Yosemite National Parks, USA

    NASA Astrophysics Data System (ADS)

    Roop, H. A.; Clow, D. W.; Mills, J.; Fenn, M. E.

    2011-12-01

    Recent increases in atmospheric deposition of nitrogen (N) in the western U.S. have adversely impacted surface water quality and changed the composition of aquatic biota in high-elevation lakes. Existing N deposition data are generally not spatially diverse; representation of remote wilderness areas and high-elevation watersheds is often lacking, making it difficult to assess the importance of variations in N deposition on water quality impacts. This study aims to better understand N deposition in remote environments, particularly in alpine environments, where both the quantity and environmental impact of atmospheric N deposition are poorly understood. Understanding the impacts of N deposition on these environments is important for National Park resource and water-quality managers. Using ion-exchange resin (IER) collectors, seasonal through-fall of nitrogen was measured at 29 sites in the Rocky Mountains and 21 sites in the Sierra Nevada from 2006-2011. The IER collectors, deployed in pairs, represent geographically diverse transects aimed to quantify the spatial distribution of nitrogen deposition. Placed on talus slopes or in areas of exposed bedrock, the IER collectors were installed immediately following snowmelt (June/July) and replaced with new collectors prior to the first snowfall (September). Following spring melt, the collectors deployed over the winter were exchanged with new collectors. These seasonal swaps capture winter/spring and summer/fall deposition. A majority of the sites were paired with seasonal surface-water quality samples, allowing for comparison with nitrate levels in surface waters. In the lab, N compounds are eluted from the resins, then diluted and analyzed on an ion- chromatograph. Preliminary data from 2006, representing 16 sites with uncontaminated samples in Rocky Mountain National Park, suggest higher nitrogen deposition on the east side of the park. Average summer N deposition for an 85-day exposure period at the eastern slope

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

    PubMed

    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. PMID:25525712

  13. External quality-assurance results for the National Atmospheric Deposition Program/National Trends Network during 1988. Water resources investigation

    SciTech Connect

    See, R.B.; Gordon, J.D.; Willoughby, T.C.

    1990-01-01

    The National Atmospheric Deposition Program (NADP) was established in 1978 as a national monitoring network to investigate acid deposition. The National Trends Network (NTN) was established in 1982 to expand the NADP effort into areas not previously sampled. Most sites in the NADP were incorporated into the NTN operation. Data collected as part of the NADP/NTN programs are used to monitor spatial and temporal trends in the chemical composition of natural wet deposition and to provide accurate data to individual scientists or agencies involved in research on the effects of acid deposition. The report describes the results of the external quality-assurance programs operated by the U.S. Geological Survey during 1988. These programs: (1) Assess the precision and accuracy of onsite determinations of pH and specific conductance; (2) evaluate the effects of onsite and laboratory protocols on the bias and precision of NADP/NTN analyte determinations; (3) determine the comparability, bias, and precision of analytical results obtained by separate laboratories when portions of a common sample were analyzed; and (4) estimate the precision of the entire sampling system.

  14. Bias and precision of selected analytes reported by the National Atmospheric Deposition Program and National Trends Network, 1984

    USGS Publications Warehouse

    Brooks, M.H.; Schroder, L.J.; Willoughby, T.C.

    1987-01-01

    The U.S. Geological Survey operated a blind audit sample program during 1974 to test the effects of the sample handling and shipping procedures used by the National Atmospheric Deposition Program and National Trends Network on the quality of wet deposition data produced by the combined networks. Blind audit samples, which were dilutions of standard reference water samples, were submitted by network site operators to the central analytical laboratory disguised as actual wet deposition samples. Results from the analyses of blind audit samples were used to calculate estimates of analyte bias associated with all network wet deposition samples analyzed in 1984 and to estimate analyte precision. Concentration differences between double blind samples that were submitted to the central analytical laboratory and separate analyses of aliquots of those blind audit samples that had not undergone network sample handling and shipping were used to calculate analyte masses that apparently were added to each blind audit sample by routine network handling and shipping procedures. These calculated masses indicated statistically significant biases for magnesium, sodium , potassium, chloride, and sulfate. Median calculated masses were 41.4 micrograms (ug) for calcium, 14.9 ug for magnesium, 23.3 ug for sodium, 0.7 ug for potassium, 16.5 ug for chloride and 55.3 ug for sulfate. Analyte precision was estimated using two different sets of replicate measures performed by the central analytical laboratory. Estimated standard deviations were similar to those previously reported. (Author 's abstract)

  15. Results of external quality-assurance program for the National Atmospheric Deposition Program and National Trends Network during 1985

    USGS Publications Warehouse

    Brooks, M.H.; Schroder, L.J.; Willoughby, T.C.

    1988-01-01

    External quality assurance monitoring of the National Atmospheric Deposition Program (NADP) and National Trends Network (NTN) was performed by the U.S. Geological Survey during 1985. The monitoring consisted of three primary programs: (1) an intersite comparison program designed to assess the precision and accuracy of onsite pH and specific conductance measurements made by NADP and NTN site operators; (2) a blind audit sample program designed to assess the effect of routine field handling on the precision and bias of NADP and NTN wet deposition data; and (3) an interlaboratory comparison program designed to compare analytical data from the laboratory processing NADP and NTN samples with data produced by other laboratories routinely analyzing wet deposition samples and to provide estimates of individual laboratory precision. An average of 94% of the site operators participated in the four voluntary intersite comparisons during 1985. A larger percentage of participating site operators met the accuracy goal for specific conductance measurements (average, 87%) than for pH measurements (average, 67%). Overall precision was dependent on the actual specific conductance of the test solution and independent of the pH of the test solution. Data for the blind audit sample program indicated slight positive biases resulting from routine field handling for all analytes except specific conductance. These biases were not large enough to be significant for most data users. Data for the blind audit sample program also indicated that decreases in hydrogen ion concentration were accompanied by decreases in specific conductance. Precision estimates derived from the blind audit sample program indicate that the major source of uncertainty in wet deposition data is the routine field handling that each wet deposition sample receives. Results of the interlaboratory comparison program were similar to results of previous years ' evaluations, indicating that the participating laboratories

  16. External quality-assurance results for the National Atmospheric Deposition Program and the National Trends Network during 1986

    USGS Publications Warehouse

    See, Randolph B.; Schroder, LeRoy J.; Willoughby, Timothy C.

    1988-01-01

    During 1986, the U.S. Geological Survey operated three programs to provide external quality-assurance monitoring of the National Atmospheric Deposition Program and National Trends Network. An intersite-comparison program was used to assess the accuracy of onsite pH and specific-conductance determinations at quarterly intervals. The blind-audit program was used to assess the effect of routine sample handling on the precision and bias of program and network wet-deposition data. Analytical results from four laboratories, which routinely analyze wet-deposition samples, were examined to determine if differences existed between laboratory analytical results and to provide estimates of the analytical precision of each laboratory. An average of 78 and 89 percent of the site operators participating in the intersite-comparison met the network goals for pH and specific conductance. A comparison of analytical values versus actual values for samples submitted as part of the blind-audit program indicated that analytical values were slightly but significantly (a = 0.01) larger than actual values for pH, magnesium, sodium, and sulfate; analytical values for specific conductance were slightly less than actual values. The decreased precision in the analyses of blind-audit samples when compared to interlaboratory studies indicates that a large amount of uncertainty in network deposition data may be a result of routine field operations. The results of the interlaboratory comparison study indicated that the magnitude of the difference between laboratory analyses was small for all analytes. Analyses of deionized, distilled water blanks by participating laboratories indicated that the laboratories had difficulty measuring analyte concentrations near their reported detection limits. (USGS)

  17. Deposition of atmospheric ions to pine branches and surrogate surfaces in the vicinity of emerald lake watershed, Sequoia National Park

    NASA Astrophysics Data System (ADS)

    Bytnerowicz, A.; Dawson, P. J.; Morrison, C. L.; Poe, M. P.

    Atmospheric dry deposition of ions to branches of native Pinus contorta and Pinus monticola (natural surfaces), and nylon filters and Whatman paper filters (surrogate surfaces) were measured in the summer of 1987 in the vicinity of Emerald Lake Watershed (ELW) of the Sequoia National Park located on the western slope of the Sierra Nevada in California. Deposition fluxes of airborne NO -3, NH +4 and SO 2-4 to native pines at the ELW were much higher than in the eastern Sierra Nevada, but several times lower than deposition fluxes to natural and surrogate surfaces at the highly polluted site in the San Gabriel Mountains of southern California. Deposition fluxes of NO 3- and NH 4+ to the natural and surrogate surfaces at the ELW were much higher than deposition of SO 42-, providing the importance of N compounds in atmospheric dry deposition in this part of the western U.S. A deficit of inorganic anions in materials deposited to various surfaces indicated a possibility of substantial participation of organic acids in atmospheric dry deposition processes. Nylon and paper filters proved to be poor surrogate surfaces for the estimation of ionic dry deposition to conifer branches.

  18. The role of annual circulation and precipitation on national scale deposition of atmospheric sulphur and nitrogen compounds.

    PubMed

    Kryza, Maciej; Werner, Małgorzata; Dore, Anthony J; Błaś, Marek; Sobik, Mieczysław

    2012-10-30

    Atmospheric circulation and rainfall are important factors controlling the deposition of atmospheric pollutants. This paper aims to quantify the role of these factors in the deposition of sulphur and nitrogen compounds, using case studies in the United Kingdom and Poland. The FRAME model has been applied to calculate deposition for the base year (2005), dry and wet years (2003 and 2000 for the UK and 2003 and 1974 for Poland, respectively), and for years with contrasting annual wind patterns (1986 and 1996 for the UK, and 1998 and 1996 for Poland). Variation in annual wind and rainfall resulted in statistically significant changes in spatial patterns of deposition and the national deposition budget of sulphur and nitrogen compounds in both countries. The deposition budgets of S and N are 5% lower than for the reference year if the dry year is considered in both countries. For the wet year, there is an increase in country total deposition by up to 17%. Years with an increased frequency of eastern winds are associated with an increase in deposition of up to 14% in Poland and 8% in the UK. The national deposition budget is below the average for the years with high frequencies of W winds, especially for the UK (up to 13%). Wet deposition varies due to meteorological factors to a larger extent than dry deposition. In Poland, the changes in national deposition budget due to meteorological factors exceed the changes resulting from emission abatements in years 2000-2009 for nitrogen compounds. In the UK, emission abatements influence the national deposition budget to a larger extent than meteorological changes (except for NH(x)). The findings are important in relation to future climate changes, especially considering the potential increase in annual precipitation. This may lead to an increase in deposition over mountainous areas with sensitive ecosystems, where annual rainfall brings significant load of S and N. Changes in annual wind speed and frequency can modify the

  19. Sensitivity of Alpine and Subalpine Lakes to Atmospheric Deposition in Grand Teton National Park and Yellowstone National Park, Wyoming

    NASA Astrophysics Data System (ADS)

    Nanus, L.; Campbell, D. H.; Williams, M. W.

    2004-12-01

    Acidification of high-elevation lakes in the Western United States is of concern because of the storage and release of pollutants in snowmelt runoff combined with steep topography, granitic bedrock, and limited soils and biota. Land use managers have limited resources for sampling and thus need direction on how best to design monitoring programs. We evaluated the sensitivity of 400 lakes in Grand Teton (GRTE) and Yellowstone (YELL) National Parks to acidification from atmospheric deposition of nitrogen and sulfur based on statistical relations between acid-neutralizing capacity (ANC) concentrations and basin characteristics to aid in the design of a long-term monitoring plan for Outstanding Natural Resource Waters. ANC concentrations that were measured at 52 lakes in GRTE and 23 lakes in YELL during synoptic surveys were used to calibrate the statistical models. Basin-characteristic information was derived from Geographic Information System data sets. The explanatory variables that were considered included bedrock type, basin slope, basin aspect, basin elevation, lake area, basin area, inorganic nitrogen (N) deposition, sulfate deposition, hydrogen ion deposition, basin precipitation, soil type, and vegetation type. A logistic regression model was developed and applied to lake basins greater than 1 hectare (ha) in GRTE (n=106) and YELL (n=294). For GRTE, 36 percent of lakes had a greater than 60-percent probability of having ANC concentrations less than 100 microequivalents per liter, and 14 percent of lakes had a greater than 80-percent probability of having ANC concentrations less than 100 microequivalents per liter. The elevation of the lake outlet and the area of the basin with northeast aspects were determined to be statistically significant and were used as the explanatory variables in the multivariate logistic regression model. For YELL, results indicated that 13 percent of lakes had a greater than 60-percent probability of having ANC concentrations less

  20. Deposition of Atmospheric Pollutants

    NASA Astrophysics Data System (ADS)

    Malet, L. M.

    Deposition of Atmospheric Pollutants, containing the proceedings of a colloquium held at Oberursel/Taunus, FRG, November 9-11, 1981, is divided into three main parts: dry deposition; wet deposition; and deposition on plants and vegetation.The 20 articles in the volume permit a fair survey of present-day knowledge and will be a useful tool to all working on the topic. Pollution by deposition of either the dry or wet sort is very insidious; its importance only appears in the long range, when its effects are or are almost irreversible. That is why concern was so long in emerging from decision makers.

  1. A quality-assurance assessment for constituents reported by the National Atmospheric Deposition Program and the National Trends Network

    USGS Publications Warehouse

    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.

  2. Alpine Microbial Community Responses to Climate Change and Atmospheric Nitrogen Deposition in Rocky Mountain National Park

    NASA Astrophysics Data System (ADS)

    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

  3. External quality-assurance results for the National Atmospheric Deposition Program/National Trends Network during 1991

    USGS Publications Warehouse

    Nilles, M.A.; Gordon, J.D.; Schroder, L.J.; Paulin, C.E.

    1995-01-01

    The U.S. Geological Survey used four programs in 1991 to provide external quality assurance for the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). An intersite-comparison program was used to evaluate onsite pH and specific-conductance determinations. The effects of routine sample handling, processing, and shipping of wet-deposition samples on analyte determinations and an estimated precision of analyte values and concentrations were evaluated in the blind-audit program. Differences between analytical results and an estimate of the analytical precision of four laboratories routinely measuring wet deposition were determined by an interlaboratory-comparison program. Overall precision estimates for the precipitation-monitoring system were determined for selected sites by a collocated-sampler program. Results of the intersite-comparison program indicated that 93 and 86 percent of the site operators met the NADP/NTN accuracy goal for pH determinations during the two intersite-comparison studies completed during 1991. The results also indicated that 96 and 97 percent of the site operators met the NADP/NTN accuracy goal for specific-conductance determinations during the two 1991 studies. The effects of routine sample handling, processing, and shipping, determined in the blind-audit program indicated significant positive bias (a=.O 1) for calcium, magnesium, sodium, potassium, chloride, nitrate, and sulfate. Significant negative bias (or=.01) was determined for hydrogen ion and specific conductance. Only ammonium determinations were not biased. A Kruskal-Wallis test indicated that there were no significant (*3t=.01) differences in analytical results from the four laboratories participating in the interlaboratory-comparison program. Results from the collocated-sampler program indicated the median relative error for cation concentration and deposition exceeded eight percent at most sites, whereas the median relative error for sample volume

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

    USGS Publications Warehouse

    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.

  5. Evaluation of candidate rain gages for upgrading precipitation measurement tools for the National Atmospheric Deposition Program

    USGS Publications Warehouse

    Gordon, John D.

    2003-01-01

    The National Atmospheric Deposition Program (NADP) was established in 1977 to investigate atmospheric deposition and its effects on the environment. Since its establishment, precipitation records have been obtained at all NADP sites using a gage developed approximately 50 years ago-the Belfort 5-780 mechanical rain gage. In 1998 and 1999, a study was done by the U.S. Geological Survey to evaluate four recently developed, technologically advanced rain gages as possible replacement candidates for the mechanical gage currently (2002) in use by the NADP. The gage types evaluated were the Belfort 3200, Geonor T-200, ETI Noah II, and the OTT PLUVIO. The Belfort 5-780 was included in the study to compare the performance of the rain gage currently (2002) used by NADP to the performance of the more recently developed gages. As a reference gage, the NovaLynx Model 260-2510 National Weather Service type stick gage also was included in the study. Two individual gages of each type were included in the study to evaluate precision between gages of the same type. A two-phase evaluation was completed. Phase I consisted of indoor bench tests with known amounts of simulated rainfall applied in 20 individual tests. Phase II consisted of outdoor testing by collecting precipitation during a 26-week period near Bay St. Louis, Mississippi. The ETI Noah II, OTT PLUVIO, and NovaLynx stick gages consistently recorded depths more commensurate with the amounts of applied simulated rainfall in Phase I testing than the Geonor T-200, Belfort 5-780, and Belfort 3200 gages. Gages where both the median difference between the measured and applied simulated rainfall and the interquartile range of all of their measured minus applied simulated rainfall differences were small (less than or equal to 0.01 inch) were judged to have performed very well in Phase I testing. The median and interquartile-range values were 0.01 inch or less for each of the ETI Noah II gages, OTT PLUVIO gages, and NovaLynx stick

  6. U.S. Geological Survey external quality-assurance project report to the National Atmospheric Deposition Program / National Trends Network and Mercury Deposition Network, 2007-08

    USGS Publications Warehouse

    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.

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

    USGS Publications Warehouse

    Wetherbee, Gregory A.; Martin, RoseAnn

    2016-01-01

    The Mercury Deposition Network programs include the system blank program and an interlaboratory comparison program. System blank results indicated that maximum total mercury contamination concentrations in samples were less than the third percentile of all Mercury Deposition Network sample concentrations. The Mercury Analytical Laboratory produced chemical concentration results with low bias and variability compared with other domestic and international laboratories that support atmospheric-deposition monitoring.

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

    USGS Publications Warehouse

    Wetherbee, Gregory A.; Martin, RoseAnn

    2016-07-05

    The Mercury Deposition Network programs include the system blank program and an interlaboratory comparison program. System blank results indicated that maximum total mercury contamination concentrations in samples were less than the third percentile of all Mercury Deposition Network sample concentrations. The Mercury Analytical Laboratory produced chemical concentration results with low bias and variability compared with other domestic and international laboratories that support atmospheric-deposition monitoring.

  9. Deposited atmospheric chemicals

    SciTech Connect

    Schell, W.R.

    1986-09-01

    A mountaintop bog in western Pennsylvania serves as a reservoir for materials deposited from the atmosphere. Biological activity in the bog decomposes plant matter, which becomes humified and mineralized at increasing depths. Little or no mixing of elements occurs below the active root zone. Radionuclides produced by natural means and by nuclear weapons have been used to measure the ages of the layers deposited during the growing season of each year. The upper layers of the bog indicate that the deposition of total sulfur is at least 20 times and that of nitrogen is 45 times the value estimated prior to cutting the forest, with a doubling time for each of 25-35 yr. Bromine deposition also doubles every 35 yr. The pattern of mass and element deposition illustrates the changes in land use and industrial effluents that were sources for the material deposited on the bog. The decrease in atmospheric particle removal shows up in the 1960 and later layers. Compared with terrestrial abundances, the relative enrichments over time for chlorine, nitrogen, sulfur, and bromine are more than 100 times those calculated for 1817; lead, calcium, and antimony are 10 to 40 times greater.

  10. External quality-assurance results for the National Atmospheric Deposition Program/National Trends Network, 2002-03

    USGS Publications Warehouse

    Wetherbee, Gregory A.; Latysh, Natalie E.; Burke, Kevin P.

    2005-01-01

    Six external quality-assurance programs were operated by the U.S. Geological Survey (USGS) External Quality-Assurance (QA) Project for the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) from 2002 through 2003. Each program measured specific components of the overall error inherent in NADP/NTN wet-deposition measurements. The intersite-comparison program assessed the variability and bias of pH and specific conductance determinations made by NADP/NTN site operators twice per year with respect to accuracy goals. The percentage of site operators that met the pH accuracy goals decreased from 92.0 percent in spring 2002 to 86.3 percent in spring 2003. In these same four intersite-comparison studies, the percentage of site operators that met the accuracy goals for specific conductance ranged from 94.4 to 97.5 percent. The blind-audit program and the sample-handling evaluation (SHE) program evaluated the effects of routine sample handling, processing, and shipping on the chemistry of weekly NADP/NTN samples. The blind-audit program data indicated that the variability introduced by sample handling might be environmentally significant to data users for sodium, potassium, chloride, and hydrogen ion concentrations during 2002. In 2003, the blind-audit program was modified and replaced by the SHE program. The SHE program was designed to control the effects of laboratory-analysis variability. The 2003 SHE data had less overall variability than the 2002 blind-audit data. The SHE data indicated that sample handling buffers the pH of the precipitation samples and, in turn, results in slightly lower conductivity. Otherwise, the SHE data provided error estimates that were not environmentally significant to data users. The field-audit program was designed to evaluate the effects of onsite exposure, sample handling, and shipping on the chemistry of NADP/NTN precipitation samples. Field-audit results indicated that exposure of NADP/NTN wet-deposition samples

  11. Effects of equipment performance on data quality from the National Atmospheric Deposition Program/National Trends Network and the Mercury Deposition Network

    USGS Publications Warehouse

    Wetherbee, Gregory A.; Rhodes, Mark F.

    2013-01-01

    The U.S. Geological Survey Branch of Quality Systems operates the Precipitation Chemistry Quality Assurance project (PCQA) to provide independent, external quality-assurance for the National Atmospheric Deposition Program (NADP). NADP is composed of five monitoring networks that measure the chemical composition of precipitation and ambient air. PCQA and the NADP Program Office completed five short-term studies to investigate the effects of equipment performance with respect to the National Trends Network (NTN) and Mercury Deposition Network (MDN) data quality: sample evaporation from NTN collectors; sample volume and mercury loss from MDN collectors; mercury adsorption to MDN collector glassware, grid-type precipitation sensors for precipitation collectors, and the effects of an NTN collector wind shield on sample catch efficiency. Sample-volume evaporation from an NTN Aerochem Metrics (ACM) collector ranged between 1.1–33 percent with a median of 4.7 percent. The results suggest that weekly NTN sample evaporation is small relative to sample volume. MDN sample evaporation occurs predominantly in western and southern regions of the United States (U.S.) and more frequently with modified ACM collectors than with N-CON Systems Inc. collectors due to differences in airflow through the collectors. Variations in mercury concentrations, measured to be as high as 47.5 percent per week with a median of 5 percent, are associated with MDN sample-volume loss. Small amounts of mercury are also lost from MDN samples by adsorption to collector glassware irrespective of collector type. MDN 11-grid sensors were found to open collectors sooner, keep them open longer, and cause fewer lid cycles than NTN 7-grid sensors. Wind shielding an NTN ACM collector resulted in collection of larger quantities of precipitation while also preserving sample integrity.

  12. National Acid Precipitation Assessment Program (NAPAP) Interim Assessment: the causes and effects of acidic deposition. Volume 3. Atmospheric processes

    SciTech Connect

    Not Available

    1987-01-01

    This volume on Atmospheric Processes and Deposition is the third in a four volume set which comprises the NAPAP Interim Assessment. It contains two chapters dealing with (4) Atmospheric Processes, and (5) Acidic Deposition and Air Quality. Volume II, Emissions and Controls, contains chapters on (1) Historical Emissions, (2) Emission Control Technologies, and (3) Future Emissions. Volume IV, Effects of Acidic Deposition, contains chapters on (6) Agricultural Crops, (7) Forests, (8) Aquatic Systems, (9) Materials, and (10) Human Health and Visibility. Each of these chapters describes the National Program's research orientation and major conclusions within each of the ten primary areas of substantive concern. In order to learn how these first-order conclusions relate to the issue of acidic deposition in an overall, or synoptic, sense the reader is directed to Volume I, Executive Summary and Major Conclusions, where the conclusions from each of the ten chapters are distilled in a manner that will allow interested parties to quickly reference the status of a variety of factors that pertain to the scientific understanding of acidic deposition.

  13. Glacial atmospheric phosphorus deposition

    NASA Astrophysics Data System (ADS)

    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).

  14. National Atmospheric Deposition Program/National Trends Network (NADP/NTN) site visitation program: summary report for the period December 1984 through September 1986

    SciTech Connect

    Eaton, W.C.; Tew, E.L.; Moore, C.E.; Ward, D.A.

    1987-11-01

    The proper collection of precipitation and the accurate measurement of its constituents are important steps in attaining a better understanding of the distribution and effects of acid rain in the United States. One of NAPAP Task Group IV's major programs concerns wet deposition monitoring. The document is a summary report of the findings from the 1985-1986 Site Visitation Program to the 195 sites that comprise the National Atmospheric Deposition Program and National Trends Network precipitation networks, referred to collectively as the NADP/NTN network.

  15. Precision and bias of selected analytes reported by the National Atmospheric Deposition Program and National Trends Network, 1983; and January 1980 through September 1984

    USGS Publications Warehouse

    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)

  16. External quality-assurance results for the national atmospheric deposition program/national trends network, 2000-2001

    USGS Publications Warehouse

    Wetherbee, Gregory A.; Latysh, Natalie E.; Gordon, John D.

    2004-01-01

    Five external quality-assurance programs were operated by the U.S. Geological Survey for the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) from 2000 through 2001 (study period): the intersite-comparison program, the blind-audit program, the field-audit program, the interlaboratory-comparison program, and the collocated-sampler program. Each program is designed to measure specific components of the total error inherent in NADP/NTN wet-deposition measurements. The intersite-comparison program assesses the variability and bias of pH and specific-conductance determinations made by NADP/NTN site operators with respect to accuracy goals. The accuracy goals are statistically based using the median of all of the measurements obtained for each of four intersite-comparison studies. The percentage of site operators responding on time that met the pH accuracy goals ranged from 84.2 to 90.5 percent. In these same four intersite-comparison studies, 88.9 to 99.0 percent of the site operators met the accuracy goals for specific conductance. The blind-audit program evaluates the effects of routine sample handling, processing, and shipping on the chemistry of weekly precipitation samples. The blind-audit data for the study period indicate that sample handling introduced a small amount of sulfate contamination and slight changes to hydrogen-ion content of the precipitation samples. The magnitudes of the paired differences are not environmentally significant to NADP/NTN data users. The field-audit program (also known as the 'field-blank program') was designed to measure the effects of field exposure, handling, and processing on the chemistry of NADP/NTN precipitation samples. The results indicate potential low-level contamination of NADP/NTN samples with calcium, ammonium, chloride, and nitrate. Less sodium contamination was detected by the field-audit data than in previous years. Statistical analysis of the paired differences shows that contaminant ions

  17. Trends in snowpack chemistry and comparison to National Atmospheric Deposition Program results for the Rocky Mountains, US, 1993-2004

    USGS Publications Warehouse

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

    2008-01-01

    Seasonal snowpack chemistry data from the Rocky Mountain region of the US was examined to identify long-term trends in concentration and chemical deposition in snow and in snow-water equivalent. For the period 1993-2004, comparisons of trends were made between 54 Rocky Mountain Snowpack sites and 16 National Atmospheric Deposition Program wetfall sites located nearby in the region. The region was divided into three subregions: Northern, Central, and Southern. A non-parametric correlation method known as the Regional Kendall Test was used. This technique collectively computed the slope, direction, and probability of trend for several sites at once in each of the Northern, Central, and Southern Rockies subregions. Seasonal Kendall tests were used to evaluate trends at individual sites. Significant trends occurred during the period in wetfall and snowpack concentrations and deposition, and in precipitation. For the comparison, trends in concentrations of ammonium, nitrate, and sulfate for the two networks were in fair agreement. In several cases, increases in ammonium and nitrate concentrations, and decreases in sulfate concentrations for both wetfall and snowpack were consistent in the three subregions. However, deposition patterns between wetfall and snowpack more often were opposite, particularly for ammonium and nitrate. Decreases in ammonium and nitrate deposition in wetfall in the central and southern rockies subregions mostly were moderately significant (p<0.11) in constrast to highly significant increases in snowpack (p<0.02). These opposite trends likely are explained by different rates of declining precipitation during the recent drought (1999-2004) and increasing concentration. Furthermore, dry deposition was an important factor in total deposition of nitrogen in the region. Sulfate deposition decreased with moderate to high significance in all three subregions in both wetfall and snowpack. Precipitation trends consistently were downward and significant for

  18. Modeled subalpine plant community response to climate change and atmospheric nitrogen deposition in Rocky Mountain National Park, USA.

    PubMed

    McDonnell, T C; Belyazid, S; Sullivan, T J; Sverdrup, H; Bowman, W D; Porter, E M

    2014-04-01

    To evaluate potential long-term effects of climate change and atmospheric nitrogen (N) deposition on subalpine ecosystems, the coupled biogeochemical and vegetation community competition model ForSAFE-Veg was applied to a site at the Loch Vale watershed of Rocky Mountain National Park, Colorado. Changes in climate and N deposition since 1900 resulted in pronounced changes in simulated plant species cover as compared with ambient and estimated future community composition. The estimated critical load (CL) of N deposition to protect against an average future (2010-2100) change in biodiversity of 10% was between 1.9 and 3.5 kg N ha(-1) yr(-1). Results suggest that the CL has been exceeded and vegetation at the study site has already undergone a change of more than 10% as a result of N deposition. Future increases in air temperature are forecast to cause further changes in plant community composition, exacerbating changes in response to N deposition alone.

  19. Use of regression-based models to map sensitivity of aquatic resources to atmospheric deposition in Yosemite National Park, USA

    USGS Publications Warehouse

    Clow, David W.; Nanus, Leora; Huggett, Brian

    2010-01-01

    An abundance of exposed bedrock, sparse soil and vegetation, and fast hydrologic flushing rates make aquatic ecosystems in Yosemite National Park susceptible to nutrient enrichment and episodic acidification due to atmospheric deposition of nitrogen (N) and sulfur (S). In this study, multiple linear regression (MLR) models were created to estimate fall-season nitrate and acid neutralizing capacity (ANC) in surface water in Yosemite wilderness. Input data included estimated winter N deposition, fall-season surface-water chemistry measurements at 52 sites, and basin characteristics derived from geographic information system layers of topography, geology, and vegetation. The MLR models accounted for 84% and 70% of the variance in surface-water nitrate and ANC, respectively. Explanatory variables (and the sign of their coefficients) for nitrate included elevation (positive) and the abundance of neoglacial and talus deposits (positive), unvegetated terrain (positive), alluvium (negative), and riparian (negative) areas in the basins. Explanatory variables for ANC included basin area (positive) and the abundance of metamorphic rocks (positive), unvegetated terrain (negative), water (negative), and winter N deposition (negative) in the basins. The MLR equations were applied to 1407 stream reaches delineated in the National Hydrography Data Set for Yosemite, and maps of predicted surface-water nitrate and ANC concentrations were created. Predicted surface-water nitrate concentrations were highest in small, high-elevation cirques, and concentrations declined downstream. Predicted ANC concentrations showed the opposite pattern, except in high-elevation areas underlain by metamorphic rocks along the Sierran Crest, which had relatively high predicted ANC (>200 μeq L-1). Maps were created to show where basin characteristics predispose aquatic resources to nutrient enrichment and acidification effects from N and S deposition. The maps can be used to help guide development of

  20. External quality-assurance results for the National Atmospheric Deposition Program/National Trends Network, 1995-96

    USGS Publications Warehouse

    Gordon, John D.

    1999-01-01

    The U.S. Geological Survey operated four external quality-assurance programs for the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) in 1995 and 1996: the intersite-comparison program, the blind-audit program, the interlaboratory- comparison program, and the collocated-sampler program. The intersite-comparison program assessed the precision and bias of pH and specific-conductance determinations made by NADP/NTN site operators. The analytical bias introduced during routine handling, processing, and shipping of wet-deposition samples and precision of analyte values was estimated using a blind-audit program. An interlaboratory-comparison program was used to evaluate differences between analytical results and to estimate the analytical precision of five North American laboratories that routinely analyzed wet deposition. A collocated-sampler program estimated the precision of the overall precipitation collection and analysis system from initial sample collection through final storage of the data. Results of two intersite-comparison studies completed in 1995 indicated 94.6 and 94.4 percent of the onsite pH determinations met the NADP/NTN accuracy goals, whereas 97.2 and 98.3 percent of the specific-conductance determinations were within the established limits. The percentages of onsite determinations that met the accuracy goals in 1996 were slightly less for both pH and specific-conductance than in 1995. In 1996, 93.2 and 87.5 percent of onsite pH determinations met the accuracy goals, whereas the percentage of onsite specific-conductance measurements that met the goals was 93.9 and 94.9 percent.The blind audit program utilizes a paired sample design to evaluate the effects of routine sample handling, processing and shipping on the chemistry of weekly precipitation samples. The portion of the blind audit sample subject to all of the normal onsite handling and processing steps of a regular weekly precipitation sample is referred to as the bucket

  1. Evaluation of OTT PLUVIO Precipitation Gage versus Belfort Universal Precipitation Gage 5-780 for the National Atmospheric Deposition Program

    USGS Publications Warehouse

    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.

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

    USGS Publications Warehouse

    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

  3. Evaluation of National Atmospheric Deposition Program measurements for colocated sites CO89 and CO98 at Rocky Mountain National Park, water years 2010–14

    USGS Publications Warehouse

    Wetherbee, Gregory A.

    2016-07-22

    Atmospheric wet-deposition monitoring in Rocky Mountain National Park included precipitation depth and aqueous chemical measurements at colocated National Atmospheric Deposition Program/National Trends Network (NADP/NTN) sites CO89 and CO98 (Loch Vale) during water years 2010–14 (study period). The colocated sites were separated by approximately 6.5 meters horizontally and 0.5 meter in elevation, in accordance with NADP siting criteria. Assessment of the 5-year record of colocated data is intended to inform man-agement decisions pertaining to the achievement of nitrogen deposition reduction goals of the Rocky Mountain National Park Nitrogen Deposition Reduction Plan.The data at site CO98 met NADP completeness criteria for the first time in 29 years of operation in 2011 and then again in 2012. During the study period, data at site CO89 met completeness criteria in 2012. Median weekly relative precipitation-depth differences between sites CO89 and CO98 ranged from 0 to 0.25 millimeter during the study period. Median weekly absolute percent differences in sample volume ranged from 5 to 10 percent. Median relative concentration differences for weekly ammonium (NH4+) and nitrate (NO3-) concentrations were near the NADP Central Analytical Laboratory’s method detection limits and thus were considered small. Absolute percent differences for water-year 2010–14 precipitation-weighted mean concentrations of NH4+, NO3-, and inorganic nitrogen (Ninorg) ranged from 0.0 to 25.7 percent. Absolute percent differences for water-year 2010–14 NH4+, NO3-, and Ninorg deposition ranged from 2.1 to 18.9 percent, 3.3 to 24.5 percent, and 0.3 to 17.4 percent, respectively.

  4. External quality-assurance results for the National Atmospheric Deposition Program/National Trends Network, 1997-99

    USGS Publications Warehouse

    Gordon, John D.; Latysh, Natalie E.; Lindholm, Sandy J.

    2003-01-01

    Five external quality-assurance programs were operated by the U.S. Geological Survey for the National Atmospheric Deposition Program/ National Trends Network (NADP/NTN) during 1997 through 1999: the intersite-comparison program, the blind-audit program, the field- audit program, the interlaboratory-comparison program, and the collocated-sampler program. The intersite-comparison program assesses the accuracy of pH and specific-conductance determinations made by NADP/NTN site operators. In two 1997 intersite-comparison studies, 83.7 and 85.8 percent of the pH determinations met the NADP/NTN accuracy goals, whereas 97.3 and 92.4 percent of the specific-conductance determinations met the NADP/NTN accuracy goals. The percentage of pH and specific-conductance determinations that met the accuracy goals in 1998 were, for the most part, higher than in 1997. In two 1998 studies, 90.9 and 90.3 percent of the pH determinations met the accuracy goals compared to 94.7 and 96.0 percent of the specific- conductance measurements meeting the accuracy goals. In one 1999 intersite-comparison study, 89.5 percent and 99.4 percent of pH and specific- conductance determinations, respectively, met the NADP/NTN accuracy goals. The blind-audit program evaluates the effects of routine sample handling, processing, and shipping on the analytical bias and precision of weekly precipitation samples. A portion of the blind-audit sample subject to the normal onsite handling and processing of a weekly precipitation sample is referred to as the bucket portion, whereas the portion receiving only minimal handling is referred to as the bottle portion. Positive bias in regard to blind-audit results indicates that the bucket portion has a higher concentration than the bottle portion. The paired t-test for the 1997 through 1999 blind- audit data indicates that routine sample handling, processing, and shipping introduced a positive bias (a=0.05) for calcium and chloride and a negative bias (cz=0.05) for

  5. Mercury in soils, lakes, and fish in Voyageurs National Park (Minnesota): Importance of atmospheric deposition and ecosystem factors

    USGS Publications Warehouse

    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.

  6. Temporal and Spatial Variation of Atmospherically Deposited Organic Contaminants at High Elevation in Yosemite National Park, California, USA

    EPA Science Inventory

    Atmospherically deposited organic contaminants in the Sierra Nevada mountains of California, USA, have exceeded some thresholds of concern, but the spatial and temporal distributions of contaminants in the mountains are not well known. The present study evaluated (1) whether the...

  7. Atmospheric deposition maps for the Rocky Mountains

    USGS Publications Warehouse

    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.

  8. External Quality Assurance Programs Managed by the U.S. Geological Survey in Support of the National Atmospheric Deposition Program/Mercury Deposition Network

    USGS Publications Warehouse

    Latysh, Natalie E.; Wetherbee, Gregory A.

    2007-01-01

    The U.S. Geological Survey (USGS) Branch of Quality Systems operates external quality assurance programs for the National Atmospheric Deposition Program/Mercury Deposition Network (NADP/MDN). Beginning in 2004, three programs have been implemented: the system blank program, the interlaboratory comparison program, and the blind audit program. Each program was designed to measure error contributed by specific components in the data-collection process. The system blank program assesses contamination that may result from sampling equipment, field exposure, and routine handling and processing of the wet-deposition samples. The interlaboratory comparison program evaluates bias and precision of analytical results produced by the Mercury Analytical Laboratory (HAL) for the NADP/MDN, operated by Frontier GeoSciences, Inc. The HAL's performance is compared with the performance of five other laboratories. The blind audit program assesses bias and variability of MDN data produced by the HAL using solutions disguised as environmental samples to ascertain true laboratory performance. This report documents the implementation of quality assurance procedures for the NADP/MDN and the operating procedures for each of the external quality assurance programs conducted by the USGS. The USGS quality assurance information provides a measure of confidence to NADP/MDN data users that measurement variability is distinguished from environmental signals.

  9. Streamwater acid-base chemistry and critical loads of atmospheric sulfur deposition in Shenandoah National Park, Virginia.

    PubMed

    Sullivan, T J; Cosby, B J; Webb, J R; Dennis, R L; Bulger, A J; Deviney, F A

    2008-02-01

    A modeling study was conducted to evaluate the acid-base chemistry of streams within Shenandoah National Park, Virginia and to project future responses to sulfur (S) and nitrogen (N) atmospheric emissions controls. Many of the major stream systems in the park have acid neutralizing capacity (ANC) less than 20 microeq/L, levels at which chronic and/or episodic adverse impacts on native brook trout are possible. Model hindcasts suggested that none of these streams had ANC less than 50 microeq/L in 1900. Model projections, based on atmospheric emissions controls representative of laws already enacted as of 2003, suggested that the ANC of those streams simulated to have experienced the largest historical decreases in ANC will increase in the future. The levels of S deposition that were simulated to cause streamwater ANC to increase or decrease to three specified critical levels (0, 20, and 50 microeq/L) ranged from less than zero (ANC level not attainable) to several hundred kg/ha/year, depending on the selected site and its inherent acid-sensitivity, selected ANC endpoint criterion, and evaluation year for which the critical load was calculated. Several of the modeled streams situated on siliciclastic geology exhibited critical loads <0 kg/ha/year to achieve ANC >50 microeq/L in the year 2040, probably due at least in part to base cation losses from watershed soil. The median modeled siliciclastic stream had a calculated critical load to achieve ANC >50 microeq/L in 2100 that was about 3 kg/ha/year, or 77% lower than deposition in 1990, representing the time of model calibration.

  10. Streamwater acid-base chemistry and critical loads of atmospheric sulfur deposition in Shenandoah National Park, Virginia.

    PubMed

    Sullivan, T J; Cosby, B J; Webb, J R; Dennis, R L; Bulger, A J; Deviney, F A

    2008-02-01

    A modeling study was conducted to evaluate the acid-base chemistry of streams within Shenandoah National Park, Virginia and to project future responses to sulfur (S) and nitrogen (N) atmospheric emissions controls. Many of the major stream systems in the park have acid neutralizing capacity (ANC) less than 20 microeq/L, levels at which chronic and/or episodic adverse impacts on native brook trout are possible. Model hindcasts suggested that none of these streams had ANC less than 50 microeq/L in 1900. Model projections, based on atmospheric emissions controls representative of laws already enacted as of 2003, suggested that the ANC of those streams simulated to have experienced the largest historical decreases in ANC will increase in the future. The levels of S deposition that were simulated to cause streamwater ANC to increase or decrease to three specified critical levels (0, 20, and 50 microeq/L) ranged from less than zero (ANC level not attainable) to several hundred kg/ha/year, depending on the selected site and its inherent acid-sensitivity, selected ANC endpoint criterion, and evaluation year for which the critical load was calculated. Several of the modeled streams situated on siliciclastic geology exhibited critical loads <0 kg/ha/year to achieve ANC >50 microeq/L in the year 2040, probably due at least in part to base cation losses from watershed soil. The median modeled siliciclastic stream had a calculated critical load to achieve ANC >50 microeq/L in 2100 that was about 3 kg/ha/year, or 77% lower than deposition in 1990, representing the time of model calibration. PMID:17492359

  11. Fission products in National Atmospheric Deposition Program—Wet deposition samples prior to and following the Fukushima Dai-Ichi Nuclear Power Plant incident, March 8?April 5, 2011

    USGS Publications Warehouse

    Wetherbee, Gregory A.; Debey, Timothy M.; Nilles, Mark A.; Lehmann, Christopher M.B.; Gay, David A.

    2012-01-01

    Radioactive isotopes I-131, Cs-134, or Cs-137, products of uranium fission, were measured at approximately 20 percent of 167 sampled National Atmospheric Deposition Program monitoring sites in North America (primarily in the contiguous United States and Alaska) after the Fukushima Dai-Ichi Nuclear Power Plant incident on March 12, 2011. Samples from the National Atmospheric Deposition Program were analyzed for the period of March 8-April 5, 2011. Calculated 1- or 2-week radionuclide deposition fluxes at 35 sites from Alaska to Vermont ranged from 0.47 to 5,100 Becquerels per square meter during the sampling period of March 15-April 5, 2011. No fission-product isotopes were measured in National Atmospheric Deposition Program samples obtained during March 8-15, 2011, prior to the arrival of contaminated air in North America.

  12. Temporal and spatial variation of atmospherically deposited organic contaminants at high elevation in Yosemite National Park, California, USA.

    PubMed

    Bradford, David F; Stanley, Kerri A; Tallent, Nita G; Sparling, Donald W; Nash, Maliha S; Knapp, Roland A; McConnell, Laura L; Massey Simonich, Staci L

    2013-03-01

    Contaminants used at low elevation, such as pesticides on crops, can be transported tens of kilometers and deposited in adjacent mountains in many parts of the world. Atmospherically deposited organic contaminants in the Sierra Nevada Mountains of California, USA, have exceeded some thresholds of concern, but the spatial and temporal distributions of contaminants in the mountains are not well known. The authors sampled shallow-water sediment and tadpoles (Pseudacris sierra) for pesticides, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls in four high-elevation sites in Yosemite National Park in the central Sierra Nevada twice during the summers of 2006, 2007, and 2008. Both historic- and current-use pesticides showed a striking pattern of lower concentrations in both sediment and tadpoles in Yosemite than was observed previously in Sequoia-Kings Canyon National Parks in the southern Sierra Nevada. By contrast, PAH concentrations in sediment were generally greater in Yosemite than in Sequoia-Kings Canyon. The authors suggest that pesticide concentrations tend to be greater in Sequoia-Kings Canyon because of a longer air flow path over agricultural lands for this park along with greater pesticide use near this park. Concentrations for DDT-related compounds in some sediment samples exceeded guidelines or critical thresholds in both parks. A general pattern of difference between Yosemite and Sequoia-Kings Canyon was not evident for total tadpole cholinesterase activity, an indicator of harmful exposure to organophosphorus and carbamate pesticides. Variability of chemical concentrations among sites, between sampling periods within each year, and among years, contributed significantly to total variation, although the relative contributions differed between sediment and tadpoles.

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

    PubMed

    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.

  14. ATMOSPHERIC DEPOSITION OF CURRENT-USE AND HISTORIC-USE PESTICIDES IN SNOW AT NATIONAL PARKS IN THE WESTERN UNITED STATES

    EPA Science Inventory

    The United States (U.S.) National Park Service has initiated research on the atmospheric deposition and fate of semi-volatile organic compounds in its alpine, sub-Arctic, and Arctic ecosystems in the Western U.S. Results for the analysis of pesticides in seasonal snowpack samples...

  15. Atmospherically deposited PBDEs, pesticides, PCBs, and PAHs in western U.S. National Park fish: concentrations and consumption guidelines.

    PubMed

    Ackerman, Luke K; Schwindt, Adam R; Simonich, Staci L Massey; Koch, Dan C; Blett, Tamara F; Schreck, Carl B; Kent, Michael L; Landers, Dixon H

    2008-04-01

    Concentrations of polybrominated diphenyl ethers (PBDEs), pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons were measured in 136 fish from 14 remote lakes in 8 western U.S. National Parks/Preserves between 2003 and 2005 and compared to human and wildlife contaminant health thresholds. A sensitive (median detection limit--18 pg/g wet weight), efficient (61% recovery at 8 ng/g), reproducible (4.1% relative standard deviation (RSD)), and accurate (7% deviation from standard reference material (SRM)) analytical method was developed and validated for these analyses. Concentrations of PCBs, hexachlorobenzene, hexachlorocyclohexanes, DDTs, and chlordanes in western U.S. fish were comparable to or lower than mountain fish recently collected from Europe, Canada, and Asia. Dieldrin and PBDE concentrations were higher than recent measurements in mountain fish and Pacific Ocean salmon. Concentrations of most contaminants in western U.S. fish were 1-6 orders of magnitude below calculated recreational fishing contaminant health thresholds. However, lake average contaminant concentrations in fish exceeded subsistence fishing cancer thresholds in 8 of 14 lakes and wildlife contaminant health thresholds for piscivorous birds in 1 of 14 lakes. These results indicate that atmospherically deposited organic contaminants can accumulate in high elevation fish, reaching concentrations relevant to human and wildlife health.

  16. Atmospherically deposited PBDEs, pesticides, PCBs, and PAHs in western U.S. National Park fish: concentrations and consumption guidelines.

    PubMed

    Ackerman, Luke K; Schwindt, Adam R; Simonich, Staci L Massey; Koch, Dan C; Blett, Tamara F; Schreck, Carl B; Kent, Michael L; Landers, Dixon H

    2008-04-01

    Concentrations of polybrominated diphenyl ethers (PBDEs), pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons were measured in 136 fish from 14 remote lakes in 8 western U.S. National Parks/Preserves between 2003 and 2005 and compared to human and wildlife contaminant health thresholds. A sensitive (median detection limit--18 pg/g wet weight), efficient (61% recovery at 8 ng/g), reproducible (4.1% relative standard deviation (RSD)), and accurate (7% deviation from standard reference material (SRM)) analytical method was developed and validated for these analyses. Concentrations of PCBs, hexachlorobenzene, hexachlorocyclohexanes, DDTs, and chlordanes in western U.S. fish were comparable to or lower than mountain fish recently collected from Europe, Canada, and Asia. Dieldrin and PBDE concentrations were higher than recent measurements in mountain fish and Pacific Ocean salmon. Concentrations of most contaminants in western U.S. fish were 1-6 orders of magnitude below calculated recreational fishing contaminant health thresholds. However, lake average contaminant concentrations in fish exceeded subsistence fishing cancer thresholds in 8 of 14 lakes and wildlife contaminant health thresholds for piscivorous birds in 1 of 14 lakes. These results indicate that atmospherically deposited organic contaminants can accumulate in high elevation fish, reaching concentrations relevant to human and wildlife health. PMID:18504962

  17. Atmospherically Deposited PBDEs, Pesticides, PCBs, and PAHs in Western US National Park Fish: Concentrations and Consumption Guidelines

    PubMed Central

    Ackerman, Luke K.; Schwindt, Adam R.; Simonich, Staci L.; Koch, Dan C.; Blett, Tamara F.; Schreck, Carl B.; Kent, Michael L.; Landers, Dixon H.

    2014-01-01

    Concentrations of polybrominated diphenyl ethers (PBDEs), pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons were measured in 136 fish from 14 remote lakes in 8 western US National Parks/Preserves between 2003 and 2005 and compared to human and wildlife contaminant health thresholds. A sensitive (median detection limit −18 pg/g wet weight), efficient (61% recovery at 8 ng/g), reproducible (4.1 %RSD), and accurate (7 % deviation from SRM) analytical method was developed and validated for these analyses. Concentrations of PCBs, hexachlorobenzene, hexachlorocyclohexanes, DDTs and chlordanes in western US fish were comparable to or lower than mountain fish recently collected from Europe, Canada, and Asia. Dieldrin and PBDE concentrations were higher than recent measurements in mountain fish and Pacific Ocean salmon. Concentrations of most contaminants in western US fish were 1–6 orders of magnitude below calculated recreational fishing contaminant health thresholds. However, contaminant concentrations exceeded subsistence fishing cancer screening values in 8 of 14 lakes. Average contaminant concentrations in fish exceeded wildlife contaminant health thresholds for piscivorous mammals in 5 lakes, and piscivorous birds in all 14 lakes. These results indicate that atmospherically deposited organic contaminants can accumulate in high elevation fish, reaching concentrations relevant to human and wildlife health. PMID:18504962

  18. Atmospherically deposited PBDEs, pesticides, PCBs, and PAHs in western U.S. National Park fish: Concentrations and consumption guidelines

    USGS Publications Warehouse

    Ackerman, L.K.; Schwindt, A.R.; Simonich, S.L.M.; Koch, D.C.; Blett, T.F.; Schreck, C.B.; Kent, M.L.; Landers, D.H.

    2008-01-01

    Concentrations of polybrominated diphenyl ethers (PBDEs), pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons were measured in 136 fish from 14 remote lakes in 8 western U.S. National Parks/Preserves between 2003 and 2005 and compared to human and wildlife contaminant health thresholds. A sensitive (median detection limit, -18 pg/g wet weight), efficient (61% recovery at 8 ng/g), reproducible (4.1% relative standard deviation (RSD)), and accurate (7% deviation from standard reference material (SRM)) analytical method was developed and validated for these analyses. Concentrations of PCBs, hexachlorobenzene, hexachlorocyclohexanes, DDTs, and chlordanes in western U.S. fish were comparable to or lower than mountain fish recently collected from Europe, Canada, and Asia. Dieldrin and PBDE concentrations were higher than recent measurements in mountain fish and Pacific Ocean salmon. Concentrations of most contaminants in western U.S. fish were 1-6 orders of magnitude below calculated recreational fishing contaminant health thresholds. However, lake average contaminant concentrations in fish exceeded subsistence fishing cancer thresholds in 8 of 14 lakes and wildlife contaminant health thresholds for piscivorous birds in 1of 14 lakes. These results indicate that atmospherically deposited organic contaminants can accumulate in high elevation fish, reaching concentrations relevant to human and wildlife health. ?? 2008 American Chemical Society.

  19. Temporal and spatial variation of atmospherically deposited organic contaminants at high elevation in Yosemite National Park, California, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Atmospherically deposited organic contaminants in the Sierra Nevada Mountains of California, USA, have exceeded some thresholds of concern, yet the distributions of contaminants in the mountains are not well known and there is little knowledge of temporal variation. The present study, (1) evaluated...

  20. Trace elements in glacial meltwater at Grand Teton National Park, Wyoming: Contributions from atmospheric deposition and other sources

    NASA Astrophysics Data System (ADS)

    Carling, G. T.; Fernandez, D. P.; Tingey, D. G.

    2014-12-01

    Glaciers are a reservoir of mercury and other trace elements that have accumulated in the ice from atmospheric deposition during the industrial era. As glaciers continue to melt at an alarming rate, potentially toxic metals are released from the ice to the environment. In order to evaluate the impact of glacier melt on water quality in high elevation catchments in Grand Teton National Park, we sampled transects along the Teton and Middle Teton glaciers and proglacial streams during early-July and mid-August 2013. The glaciers were snow-covered during July, and thus water samples were primarily melt of snowpack from the previous winter. During August, the glacier ice was exposed across the ablation zone. The contrasting sample sets from July and August allowed for a comparison of water chemistry of snowmelt and glacier melt, respectively. The Teton Glacier transect included ten sample sites: four samples of surface drainage on the glacier, three near the terminal moraine, and three in Glacier Gulch stream. The Middle Teton transect included thirteen sample sites: one above the glacier, four of surface drainage on the glacier, two near the terminal moraine, two at the moraine of adjacent Teepe Glacier, and four in Garnet Canyon stream. All water samples were analyzed for total and methyl mercury, a suite of trace elements (including U, Sr, and Mn), solutes, and stable water isotopes (δ2H and δ18O). A subset of samples were analyzed for tritium to differentiate recent snowmelt from older ice melt. Preliminary results indicate that snowmelt and glacier melt were a significant source of total mercury, with little additional inputs downstream of the glaciers. Methyl mercury concentrations increased downstream of the glaciers, possibly indicating that mercury from the glaciers undergoes methylation in the proglacial streams. Other trace elements were found in low concentrations in melt water, but increased substantially downstream of the glaciers likely due to water

  1. An interpretation of differences between field and laboratory pH values reported by the national atmospheric deposition program/national trends network monitoring program

    USGS Publications Warehouse

    Bigelow, D.S.; Sisterson, D.L.; Schroder, L.J.

    1989-01-01

    Differences between field and laboratory pH values reported by the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) monitoring program from 1984 through 1986 are investigated. Median differences in hydrogen ion concentration between laboratory and field pH determinations at sites averaged -4.6 ??equiv/L in natural precipitation samples on an annual basis. The median difference found in external quality assurance samples analyzed during the same time period was -11 ??equiv/L. The results suggest a systematic bias in pH values reported by the NADP/NTN network. The bias appears to have a fixed component of approximately -7 ??equiv/L, which can be attributed to the sampling bucket and lid, and a seasonal and regional component that ranges from +4 to -22 ??equiv/L at the 10th and 90th percentiles. Differences were found to be independent of sample pH and sample volume. The magnitude of the bias has implications for the interpretation of previously published pH and hydrogen ion concentration and deposition values in the western United States.

  2. External quality-assurance programs managed by the U.S. Geological Survey in support of the National Atmospheric Deposition Program/National Trends Network

    USGS Publications Warehouse

    Latysh, Natalie E.; Wetherbee, Gregory A.

    2005-01-01

    The U.S. Geological Survey, Branch of Quality Systems, operates the external quality-assurance programs for the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). Beginning in 1978, six different programs have been implemented?the intersite-comparison program, the blind-audit program, the sample-handling evaluation program, the field-audit program, the interlaboratory-comparison program, and the collocated-sampler program. Each program was designed to measure error contributed by specific components in the data-collection process. The intersite-comparison program, which was discontinued in 2004, was designed to assess the accuracy and reliability of field pH and specific-conductance measurements made by site operators. The blind-audit and sample-handling evaluation programs, which also were discontinued in 2002 and 2004, respectively, assessed contamination that may result from sampling equipment and routine handling and processing of the wet-deposition samples. The field-audit program assesses the effects of sample handling, processing, and field exposure. The interlaboratory-comparison program evaluates bias and precision of analytical results produced by the contract laboratory for NADP, the Illinois State Water Survey, Central Analytical Laboratory, and compares its performance with the performance of international laboratories. The collocated-sampler program assesses the overall precision of wet-deposition data collected by NADP/NTN. This report documents historical operations and the operating procedures for each of these external quality-assurance programs. USGS quality-assurance information allows NADP/NTN data users to discern between actual environmental trends and inherent measurement variability.

  3. Atmospheric deposition, water-quality, and sediment data for selected lakes in Mount Rainer, North Cascades, and Olympic National Parks, Washington, 2008-10

    USGS Publications Warehouse

    Sheibley, Rich W.; Foreman, James R.; Moran, Patrick W.; Swarzenski, Peter W.

    2012-01-01

    To evaluate the potential effect from atmospheric deposition of nitrogen to high-elevation lakes, the U.S. Geological Survey partnered with the National Park Service to develop a "critical load" of nitrogen for sediment diatoms. A critical load is defined as the level of a given pollutant (in this case, nitrogen) at which detrimental effects to a target endpoint (sediment diatoms) result. Because sediment diatoms are considered one of the "first responders" to ecosystem changes from nitrogen, they are a sensitive indicator for nitrogen deposition changes in natural areas. This report presents atmospheric deposition, water quality, sediment geochronology, and sediment diatom data collected from July 2008 through August 2010 in support of this effort.

  4. Sensitivity of alpine and subalpine lakes to acidification from atmospheric deposition in Grand Teton National Park and Yellowstone National Park, Wyoming

    USGS Publications Warehouse

    Nanus, Leora; Campbell, Donald H.; Williams, Mark W.

    2005-01-01

    The sensitivity of 400 lakes in Grand Teton and Yellowstone National Parks to acidification from atmospheric deposition of nitrogen and sulfur was estimated based on statistical relations between acid-neutralizing capacity concentrations and basin characteristics to aid in the design of a long-term monitoring plan for Outstanding Natural Resource Waters. Acid-neutralizing capacity concentrations that were measured at 52 lakes in Grand Teton and 23 lakes in Yellowstone during synoptic surveys were used to calibrate the statistical models. Three acid-neutralizing capacity concentration bins (bins) were selected that are within the U.S. Environmental Protection Agency criteria of sensitive to acidification; less than 50 microequivalents per liter (?eq/L) (0-50), less than 100 ?eq/L (0-100), and less than 200 ?eq/L (0-200). The development of discrete bins enables resource managers to have the ability to change criteria based on the focus of their study. Basin-characteristic information was derived from Geographic Information System data sets. The explanatory variables that were considered included bedrock type, basin slope, basin aspect, basin elevation, lake area, basin area, inorganic nitrogen deposition, sulfate deposition, hydrogen ion deposition, basin precipitation, soil type, and vegetation type. A logistic regression model was developed and applied to lake basins greater than 1 hectare in Grand Teton (n = 106) and Yellowstone (n = 294). A higher percentage of lakes in Grand Teton than in Yellowstone were predicted to be sensitive to atmospheric deposition in all three bins. For Grand Teton, 7 percent of lakes had a greater than 60-percent probability of having acid-neutralizing capacity concentrations in the 0-50 bin, 36 percent of lakes had a greater than 60-percent probability of having acid-neutralizing capacity concentrations in the 0-100 bin, and 59 percent of lakes had a greater than 60-percent probability of having acid-neutralizing capacity

  5. STREAMWATER ACID-BASED CHEMISTRY AND CRITICAL LOADS OF ATMOSPHERIC SULFUR DEPOSITION IN SHENANDOAH NATIONAL PARK, VIRGINIA

    EPA Science Inventory

    A modeling study was conducted to evaluate the acid-base chemistry of streams within Shenandoah National Park, Virginia and to project future responses to sulfur (S) and nitrogen (N) atmospheric emissions controls. Many of the major stream systems in the Park have acid neutraliz...

  6. ATMOSPHERIC MERCURY TRANSPORT AND DEPOSITION

    EPA Science Inventory

    The current state of our scientific understanding the mercury cycle tells us that most of the mercury getting into fish comes from atmospheric deposition, but methylation of that mercury in aquatic systems is required for the concentrations in fish to reach harmful levels. We st...

  7. Atmospheric Deposition and Surface-Water Chemistry in Mount Rainier and North Cascades National Parks, U.S.A., Water Years 2000 and 2005-2006

    USGS Publications Warehouse

    Clow, David W.; Campbell, Donald H.

    2008-01-01

    High-elevation aquatic ecosystems in Mount Rainier and North Cascades National Parks are highly sensitive to atmospheric deposition of nitrogen and sulfur. Thin, rocky soils promote fast hydrologic flushing rates during snowmelt and rain events, limiting the ability of basins to neutralize acidity and assimilate nitrogen deposited from the atmosphere. Potential effects of nitrogen and sulfur deposition include episodic or chronic acidification of terrestrial and aquatic ecosystems. In addition, nitrogen deposition can cause eutrophication of water bodies and changes in species composition in lakes and streams. This report documents results of a study performed by the U.S. Geological Survey, in cooperation with the National Park Service, of the effects of atmospheric deposition of nitrogen and sulfur on surface-water chemistry in Mount Rainier and North Cascades National Parks. Inorganic nitrogen in wet deposition was highest in the vicinity of North Cascades National Park, perhaps due to emissions from human sources and activities in the Puget Sound area. Sulfur in wet deposition was highest near the Pacific coast, reflecting the influence of marine aerosols. Dry deposition generally accounted for less than 30 percent of wet plus dry inorganic nitrogen and sulfur deposition, but occult deposition (primarily fog) represents a potentially substantial unmeasured component of total deposition. Trend analyses indicate inorganic nitrogen in wet deposition was relatively stable during 1986-2005, but sulfur in wet deposition declined substantially during that time, particularly after 2001, when emissions controls were added to a large powerplant in western Washington. Surface-water sulfate concentrations at the study site nearest the powerplant showed a statistically significant decrease between 2000 and 2005-06, but there was no statistically significant change in alkalinity, indicating a delayed response in surface-water alkalinity. Seasonal patterns in surface

  8. Spatial patterns of atmospheric deposition of nitrogen and sulfur using ion-exchange resin collectors in Rocky Mountain National Park, USA

    USGS Publications Warehouse

    Clow, David W.; Roop, Heidi; Nanus, Leora; Fenn, Mark; Sexstone, Graham A.

    2015-01-01

    Lakes and streams in Class 1 wilderness areas in the western United States (U.S.) are at risk from atmospheric deposition of nitrogen (N) and sulfur (S), and protection of these resources is mandated under the Federal Clean Air Act and amendments. Assessment of critical loads, which are the maximum exposure to pollution an area can receive without adverse effects on sensitive ecosystems, requires accurate deposition estimates. However, deposition is difficult and expensive to measure in high-elevation wilderness, and spatial patterns in N and S deposition in these areas remain poorly quantified. In this study, ion-exchange resin (IER) collectors were used to measure dissolved inorganic N (DIN) and S deposition during June 2006–September 2007 at approximately 20 alpine/subalpine sites spanning the Continental Divide in Rocky Mountain National Park. Results indicated good agreement between deposition estimated from IER collectors and commonly used wet + dry methods during summer, but poor agreement during winter. Snowpack sampling was found to be a more accurate way of quantifying DIN and S deposition during winter. Summer DIN deposition was significantly greater on the east side of the park than on the west side (25–50%; p ≤ 0.03), consistent with transport of pollutants to the park from urban and agricultural areas to the east. Sources of atmospheric nitrate (NO3−) were examined using N isotopes. The average δ15N of NO3− from IER collectors was 3.5‰ higher during winter than during summer (p < 0.001), indicating a seasonal shift in the relative importance of regional NOxsources, such as coal combustion and vehicular sources of atmospheric NO3−. There were no significant differences in δ15N of NO3− between east and west sides of the park during summer or winter (p = 0.83), indicating that the two areas may have similar sources of atmospheric NO3−. Results from this study indicate that a combination of IER collectors and snowpack

  9. Spatial patterns of atmospheric deposition of nitrogen and sulfur using ion-exchange resin collectors in Rocky Mountain National Park, USA

    NASA Astrophysics Data System (ADS)

    Clow, David W.; Roop, Heidi A.; Nanus, Leora; Fenn, Mark E.; Sexstone, Graham A.

    2015-01-01

    Lakes and streams in Class 1 wilderness areas in the western United States (U.S.) are at risk from atmospheric deposition of nitrogen (N) and sulfur (S), and protection of these resources is mandated under the Federal Clean Air Act and amendments. Assessment of critical loads, which are the maximum exposure to pollution an area can receive without adverse effects on sensitive ecosystems, requires accurate deposition estimates. However, deposition is difficult and expensive to measure in high-elevation wilderness, and spatial patterns in N and S deposition in these areas remain poorly quantified. In this study, ion-exchange resin (IER) collectors were used to measure dissolved inorganic N (DIN) and S deposition during June 2006-September 2007 at approximately 20 alpine/subalpine sites spanning the Continental Divide in Rocky Mountain National Park. Results indicated good agreement between deposition estimated from IER collectors and commonly used wet + dry methods during summer, but poor agreement during winter. Snowpack sampling was found to be a more accurate way of quantifying DIN and S deposition during winter. Summer DIN deposition was significantly greater on the east side of the park than on the west side (25-50%; p ≤ 0.03), consistent with transport of pollutants to the park from urban and agricultural areas to the east. Sources of atmospheric nitrate (NO3-) were examined using N isotopes. The average δ15N of NO3- from IER collectors was 3.5‰ higher during winter than during summer (p < 0.001), indicating a seasonal shift in the relative importance of regional NOx sources, such as coal combustion and vehicular sources of atmospheric NO3-. There were no significant differences in δ15N of NO3- between east and west sides of the park during summer or winter (p = 0.83), indicating that the two areas may have similar sources of atmospheric NO3-. Results from this study indicate that a combination of IER collectors and snowpack sampling can be used to

  10. ATMOSPHERIC DEPOSITION MODELING AND MONITORING OF NUTRIENTS

    EPA Science Inventory

    This talk presents an overview of the capabilities and roles that regional atmospheric deposition models can play with respect to multi-media environmental problems. The focus is on nutrient deposition (nitrogen). Atmospheric deposition of nitrogen is an important contributor to...

  11. Biogeochemical responses of two alpine lakes to climate change and atmospheric deposition, Jasper and Banff National Parks, Canadian Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Hobbs, W.; Vinebrooke, R. D.; Wolfe, A. P.

    2012-12-01

    The sensitivity of remote alpine ecosystems to global change has been documented by 20th century changes in climate, glacial recession, and terrestrial and aquatic ecosystems. In many cases the magnitude and dominance of abiotic drivers on recent changes in alpine lakes is often mediated by processes within the hydrologic catchment. Here we present sedimentary records of biogeochemical responses in two alpine lake ecosystems to multiple environmental drivers over the last ~ 500 years in Banff and Jasper National parks. We combine paleoecological measures of primary production (fossil microbial pigments) and diatom community structure with geochemical proxies of reactive N (Nr) deposition to describe the nature and rate of recent ecosystem changes. Curator Lake in Jasper shows a strong diatom response to the limnological effects of climate warming (e.g. thermal stratification), but little evidence of changes in Nr cycling over the last ~500 years. The response of McConnell Lake in Banff to climate change is strongly mediated by glacial activity within the catchment, and changing inputs of Nr. Our findings highlight the range of limnological responses that may be expressed by similar ecosystems subjected to comparable abiotic stressors, while further documenting the magnitude of the ecological footprint associated with recent environmental change in mountain park environments.

  12. Atmospheric deposition of current-use and historic-use pesticides in snow at national parks in the western United States.

    PubMed

    Hageman, Kimberly J; Simonich, Staci L; Campbell, Donald H; Wilson, Glenn R; Landers, Dixon H

    2006-05-15

    The United States (U.S.) National Park Service has initiated research on the atmospheric deposition and fate of semi-volatile organic compounds in its alpine, sub-Arctic, and Arctic ecosystems in the Western U.S. Results for the analysis of pesticides in seasonal snowpack samples collected in spring 2003 from seven national parks are presented herein. From a target analyte list of 47 pesticides and degradation products, the most frequently detected current-use pesticides were dacthal, chlorpyrifos, endosulfan, and gamma-hexachlorocyclohexane, whereas the mostfrequently detected historic-use pesticides were dieldrin, alpha-hexachlorocyclohexane, chlordane, and hexachlorobenzene. Correlation analysis with latitude, temperature, elevation, particulate matter, and two indicators of regional pesticide use reveal that regional current and historic agricultural practices are largely responsible for the distribution of pesticides in the national parks in this study. Pesticide deposition in the Alaskan parks is attributed to long-range transport because there are no significant regional pesticide sources. The percentage of total pesticide concentration due to regional transport (%RT) was calculated for the other parks. %RT was highest at parks with higher regional cropland intensity and for pesticides with lower vapor pressures and shorter half-lives in air.

  13. Atmospheric deposition of current-use and historic-use pesticides in snow at National Parks in the Western United States

    USGS Publications Warehouse

    Hageman, K.J.; Simonich, S.L.; Campbell, D.H.; Wilson, G.R.; Landers, D.H.

    2006-01-01

    The United States (U.S.) National Park Service has initiated research on the atmospheric deposition and fate of semi-volatile organic compounds in its alpine, sub-Arctic, and Arctic ecosystems in the Western U.S. Results for the analysis of pesticides in seasonal snowpack samples collected in spring 2003 from seven national parks are presented herein. From a target analyte list of 47 pesticides and degradation products, the most frequently detected current-use pesticides were dacthal, chlorpyrifos, endosulfan, and ??- hexachlorocyclohexane, whereas the most frequently detected historic-use pesticides were dieldrin, ??-hexachlorocyclohexane, chlordane, and hexachlorobenzene. Correlation analysis with latitude, temperature, elevation, particulate matter, and two indicators of regional pesticide use reveal that regional current and historic agricultural practices are largely responsible for the distribution of pesticides in the national parks in this study. Pesticide deposition in the Alaskan parks is attributed to long-range transport because there are no significant regional pesticide sources. The percentage of total pesticide concentration due to regional transport (%RT) was calculated for the other parks. %RT was highest at parks with higher regional cropland intensity and for pesticides with lower vapor pressures and shorter half-lives in air. ?? 2006 American Chemical Society.

  14. Atmospheric deposition to high-elevation forests

    SciTech Connect

    Lovett, G.M.; Weathers, K.C.; Lindberg, S.E. Oak Ridge National Lab., TN )

    1994-06-01

    Three important phenomena characterize atmospheric deposition to high-elevation forests: (1) multiple deposition mechanisms (wet, dry, and cloud deposition), (2) high rates of deposition, and (3) high spatial variability. The high rates of deposition are caused by changes in meteorological conditions with elevation, especially increasing wind speed and cloud immersion frequency. The high spatial variability of deposition is a result of the regulation of cloud and dry deposition rates by microclimatic and canopy structure conditions, which can be extremely heterogeneous in mountain landscapes. Spruce-fir forests are often [open quotes]hot spots[close quotes] of deposition when viewed in a landscape or regional context because of their elevation, exposure, and evergreen canopy. In this talk we will consider atmospheric depositions to high-elevation forests in both the northeastern and southeastern U.S., using field data and geographic information systems to illustrate deposition patterns.

  15. Quality-assurance results for field pH and specific-conductance measurements, and for laboratory analysis, National Atmospheric Deposition Program and National Trends Network; January 1980-September 1984

    USGS Publications Warehouse

    Schroder, L.J.; Brooks, M.H.; Malo, B.A.; Willoughby, T.C.

    1986-01-01

    Five intersite comparison studies for the field determination of pH and specific conductance, using simulated-precipitation samples, were conducted by the U.S.G.S. for the National Atmospheric Deposition Program and National Trends Network. These comparisons were performed to estimate the precision of pH and specific conductance determinations made by sampling-site operators. Simulated-precipitation samples were prepared from nitric acid and deionized water. The estimated standard deviation for site-operator determination of pH was 0.25 for pH values ranging from 3.79 to 4.64; the estimated standard deviation for specific conductance was 4.6 microsiemens/cm at 25 C for specific-conductance values ranging from 10.4 to 59.0 microsiemens/cm at 25 C. Performance-audit samples with known analyte concentrations were prepared by the U.S.G.S.and distributed to the National Atmospheric Deposition Program 's Central Analytical Laboratory. The differences between the National Atmospheric Deposition Program and national Trends Network-reported analyte concentrations and known analyte concentrations were calculated, and the bias and precision were determined. For 1983, concentrations of calcium, magnesium, sodium, and chloride were biased at the 99% confidence limit; concentrations of potassium and sulfate were unbiased at the 99% confidence limit. Four analytical laboratories routinely analyzing precipitation were evaluated in their analysis of identical natural- and simulated precipitation samples. Analyte bias for each laboratory was examined using analysis of variance coupled with Duncan 's multiple-range test on data produced by these laboratories, from the analysis of identical simulated-precipitation samples. Analyte precision for each laboratory has been estimated by calculating a pooled variance for each analyte. Interlaboratory comparability results may be used to normalize natural-precipitation chemistry data obtained from two or more of these laboratories. (Author

  16. Spatial and temporal variability of the overall error of National Atmospheric Deposition Program measurements determined by the USGS collocated-sampler program, water years 1989-2001.

    PubMed

    Wetherbee, Gregory A; Latysh, Natalie E; Gordon, John D

    2005-06-01

    Data from the U.S. Geological Survey (USGS) collocated-sampler program for the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) are used to estimate the overall error of NADP/NTN measurements. Absolute errors are estimated by comparison of paired measurements from collocated instruments. Spatial and temporal differences in absolute error were identified and are consistent with longitudinal distributions of NADP/NTN measurements and spatial differences in precipitation characteristics. The magnitude of error for calcium, magnesium, ammonium, nitrate, and sulfate concentrations, specific conductance, and sample volume is of minor environmental significance to data users. Data collected after a 1994 sample-handling protocol change are prone to less absolute error than data collected prior to 1994. Absolute errors are smaller during non-winter months than during winter months for selected constituents at sites where frozen precipitation is common. Minimum resolvable differences are estimated for different regions of the USA to aid spatial and temporal watershed analyses.

  17. Spatial and temporal variability of the overall error of National Atmospheric Deposition Program measurements determined by the USGS collocated-sampler program, water years 1989-2001

    USGS Publications Warehouse

    Wetherbee, G.A.; Latysh, N.E.; Gordon, J.D.

    2005-01-01

    Data from the U.S. Geological Survey (USGS) collocated-sampler program for the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) are used to estimate the overall error of NADP/NTN measurements. Absolute errors are estimated by comparison of paired measurements from collocated instruments. Spatial and temporal differences in absolute error were identified and are consistent with longitudinal distributions of NADP/NTN measurements and spatial differences in precipitation characteristics. The magnitude of error for calcium, magnesium, ammonium, nitrate, and sulfate concentrations, specific conductance, and sample volume is of minor environmental significance to data users. Data collected after a 1994 sample-handling protocol change are prone to less absolute error than data collected prior to 1994. Absolute errors are smaller during non-winter months than during winter months for selected constituents at sites where frozen precipitation is common. Minimum resolvable differences are estimated for different regions of the USA to aid spatial and temporal watershed analyses.

  18. Comparison of precipitation chemistry measurements obtained by the Canadian Air and Precipitation Monitoring Network and National Atmospheric Deposition Program for the period 1995-2004

    USGS Publications Warehouse

    Wetherbee, Gregory A.; Shaw, Michael J.; Latysh, Natalie E.; Lehmann, Christopher M.B.; Rothert, Jane E.

    2010-01-01

    Precipitation chemistry and depth measurements obtained by the Canadian Air and Precipitation Monitoring Network (CAPMoN) and the US National Atmospheric Deposition Program/National Trends Network (NADP/NTN) were compared for the 10-year period 1995–2004. Colocated sets of CAPMoN and NADP instrumentation, consisting of precipitation collectors and rain gages, were operated simultaneously per standard protocols for each network at Sutton, Ontario and Frelighsburg, Ontario, Canada and at State College, PA, USA. CAPMoN samples were collected daily, and NADP samples were collected weekly, and samples were analyzed exclusively by each network’s laboratory for pH, H + , Ca2+  , Mg2+  , Na + , K + , NH+4 , Cl − , NO−3 , and SO2−4 . Weekly and annual precipitation-weighted mean concentrations for each network were compared. This study is a follow-up to an earlier internetwork comparison for the period 1986–1993, published by Alain Sirois, Robert Vet, and Dennis Lamb in 2000. Median weekly internetwork differences for 1995–2004 data were the same to slightly lower than for data for the previous study period (1986–1993) for all analytes except NO−3 , SO2−4 , and sample depth. A 1994 NADP sampling protocol change and a 1998 change in the types of filters used to process NADP samples reversed the previously identified negative bias in NADP data for hydrogen-ion and sodium concentrations. Statistically significant biases (α = 0.10) for sodium and hydrogen-ion concentrations observed in the 1986–1993 data were not significant for 1995–2004. Weekly CAPMoN measurements generally are higher than weekly NADP measurements due to differences in sample filtration and field instrumentation, not sample evaporation, contamination, or analytical laboratory differences.

  19. Empirical modeling of atmospheric deposition in mountainous landscapes.

    PubMed

    Weathers, Kathleen C; Simkin, Samuel M; Lovett, Gary M; Lindberg, Steven E

    2006-08-01

    Atmospheric deposition has long been recognized as an important source of pollutants and nutrients to ecosystems. The need for reliable, spatially explicit estimates of total atmospheric deposition (wet + dry + cloud) is central, not only to air pollution effects researchers, but also for calculation of input-output budgets, and to decision makers faced with the challenge of assessing the efficacy of policy initiatives related to deposition. Although atmospheric deposition continues to represent a critical environmental and scientific issue, current estimates of total deposition have large uncertainties, particularly across heterogeneous landscapes such as montane regions. We developed an empirical modeling approach that predicts total deposition as a function of landscape features. We measured indices of total deposition to the landscapes of Acadia (121 km2) and Great Smoky Mountains (2074 km2) National Parks (USA). Using approximately 300-400 point measurements and corresponding landscape variables at each park, we constructed a statistical (general linear) model relating the deposition index to landscape variables measured in the field. The deposition indices ranged over an order of magnitude, and in response to vegetation type and elevation, which together explained approximately 40% of the variation in deposition. Then, using the independent landscape variables available in GIS data layers, we created a GIS-relevant statistical nitrogen (N) and sulfur (S) deposition model (LandMod). We applied this model to create park-wide maps of total deposition that were scaled to wet and dry deposition data from the closest national network monitoring stations. The resultant deposition maps showed high spatial heterogeneity and a four- to sixfold variation in "hot spots" and "cold spots" of N and S deposition ranging from 3 to 31 kg N x ha(-1) x yr(-1) and from 5 to 42 kg S x ha(-1) x yr(-1) across these park landscapes. Area-weighted deposition was found to be up to 70

  20. Chesapeake Bay atmospheric deposition study. Final report

    SciTech Connect

    Baker, J.E.; Clark, C.A.

    1996-08-01

    The results of the Chesapeake Bay Atmospheric Deposition Study (CBADS) are presented and discussed relative to the issues raised by the U.S. Environmental Protection Agency`s Great Waters Program. The primary objective of the CBADS network was to provide the best possible estimates of total, annual atmospheric loadings of a variety of trace elements and organic contaminants directly to the surface waters of the Chesapeake Bay.

  1. Modeling atmospheric concentrations and deposition of Hg

    SciTech Connect

    Shannon, J.D.

    1994-06-01

    The deleterious effects on ecosystems of mercury pollution are well established and fish advisories are in effect for many lakes in North America. Because methylation and other transformation processes in ecosystems can alter the original speciation of deposited Hg, a decrease in atmospheric loading of Hg in all forms is highly desirable. The contribution to Hg deposition by emissions from current anthropogenic activities relative to the deposition contribution by emissions from natural processes must be estimated to establish what fraction of atmospheric loading to watersheds and ecosystems is at least potentially amenable to control actions. Additional modeling questions concern source-receptor relationships (SRR) for major point sources and for emissions aggregated over geopolitical regions or emission sectors, because of the usefulness of SRR in comparing effectiveness of alternate control strategies. Modeling of atmospheric Hg is less advanced than that of some other widespread air pollution problems such as acid deposition. Nonetheless, several promising studies have been made for northern Europe and North America. For this study of Hg deposition in eastern North America we extend modeling techniques used extensively and successfully during the last 15 years for concentrations and deposition of SO{sub x} and NO{sub x} over regional scales, with parameterization rates adjusted to suitable values for Hg transformation and removal.

  2. Atmospheric Deposition of Metals to Forest Vegetation

    NASA Astrophysics Data System (ADS)

    Lindberg, Steven E.; Harriss, Robert C.; Turner, Ralph R.

    1982-03-01

    Atmospheric deposition during the growing season contributes one-third or more of the estimated total flux of lead, zinc, and cadium from the forest canopy to soils beneath an oak stand in the Tennessee Valley but less than 10 percent of the flux of manganese. The ratio of the wet to dry deposition flux to the vegetation during this period ranges from 0.1 for manganese to 0.8 for lead to ~ 3 to 4 for cadmium and zinc. Interactions between metal particles deposited on dry leaf surfaces and subsequent acid precipitation can result in metal concentrations on leaves that are considerably higher than those in rain alone.

  3. Atmospheric deposition of metals to forest vegetation.

    PubMed

    Lindberg, S E; Harriss, R C; Turner, R R

    1982-03-26

    Atmospheric deposition during the growing season contributes one-third or more of the estimated total flux of lead, zinc, and cadium from the forest canopy to soils beneath an oak stand in the Tennessee Valley but less than 10 percent of the flux of manganese. The ratio of the wet to dry deposition flux to the vegetation during this period ranges from 0.1 for manganese to 0.8 for lead to approximately 3 to 4 for cadmium and zinc. Interactions between metal particles deposited on dry leaf surfaces and subsequent acid precipitation can result in metal concentrations on leaves that are considerably higher than those in rain alone.

  4. How Much Atmospheric Deposition Across the US: Comparison of N and S Deposition Estimates

    NASA Astrophysics Data System (ADS)

    Weathers, K. C.; Lynch, J. A.

    2008-12-01

    Despite decades of research and monitoring efforts, generating accurate measurements of total (wet + dry) atmospheric deposition across heterogeneous landscapes is still a challenge. In addition, there have been two major, national scale approaches used for generating nitrogen (N) and sulfur (S) deposition across the US. There are two monitoring sources that, when combined with deposition models, result in S and N input estimates. Here we compare N and S total deposition as modeled using the (1) Community Multiscale Air Quality (CMAQ) modeling system, which uses air emissions data combined with chemical transformations, meterologic, and land cover data in a mechanistic model, and (2) the sum of the Clean Air Status and Trends (CASTNET) air chemistry and modeling program data for dry deposition and wet deposition estimates from the National Atmospheric Deposition Program (NADP). Here we examine wet, dry and total deposition estimates based on these two approaches. Overall, estimates of wet deposition of S and N comparisons showed close agreement (r2 = 0.79 to 0.83) while estimates of dry deposition based on the two approaches varied considerably (r2 = 0.25 to 0.67). Relative to deposition measured at NADP sites, CMAQ values slightly over represented wet sulfate deposition, but slightly underrepresented wet nitrate and ammonium input. However, CMAQ-estimated dry deposition of nitric acid was much higher than CASTNET-estimated deposition, while dry ammonium and nitrate were much lower using the CMAQ model. When compared spatially, regions that showed large differences in total N and S deposition included the Midwest and west central Appalachian mountains, showing differences of up to 6kgN or S/ha/yr.

  5. Are climate warming and enhanced atmospheric deposition of sulfur and nitrogen threatening tufa landscapes in Jiuzhaigou National Nature Reserve, Sichuan, China?

    PubMed

    Qiao, Xue; Du, Jie; Lugli, Stefano; Ren, Jinhai; Xiao, Weiyang; Chen, Pan; Tang, Ya

    2016-08-15

    Massive deposition of calcium carbonate in ambient temperature waters (tufa) can form magnificent tufa landscapes, many of which are designated as protected areas. However, tufa landscapes in many areas are threatened by both local anthropogenic activities and climate change. This study, for the first time, posed the question whether the tufa landscape degradation (characterized by tufa degradation and increased biomass of green algae) in Jiuzhaigou National Nature Reserve of China is partially caused by regional air pollution and climate warming. The results indicate that wet deposition (including rain and snow) polluted by anthropogenic SO2, NOx, and NH3 emissions dissolves exposed tufa and may considerably reduce tufa deposition rate and even cause tufa dissolution within shallow waters. These effects of wet deposition on tufa enhanced as pH of wet deposition decreased from 8.01 to 5.06. Annual Volume Weighted Mean concentration of reactive nitrogen (including NH4(+) and NO3(-)) in wet deposition (26.1μmolL(-1)) was 1.8 times of the corresponding value of runoff (14.8μmolL(-1)) and exceeded China's national standard of total nitrogen in runoff for nature reserves (14.3μmolL(-1)), indicating a direct nitrogen fertilization effect of wet deposition on green algae. As water temperature is the major limiting factor of algal growth in Jiuzhaigou and temperature in the top layer (0-5cm) of runoff (depth<1m, no canopy coverage of trees and shrubs) was significantly higher at the sites with increased biomass of green algae (p<0.05), climate warming in this region would favor algal growth. In sum, this study suggests that climate warming and enhanced sulfur and nitrogen deposition have contributed to the current degradation of tufa landscape in Jiuzhaigou, but in order to quantify the contributions, further studies are needed, as many other anthropogenic and natural processes also influence tufa landscape evolution. PMID:27110983

  6. Are climate warming and enhanced atmospheric deposition of sulfur and nitrogen threatening tufa landscapes in Jiuzhaigou National Nature Reserve, Sichuan, China?

    PubMed

    Qiao, Xue; Du, Jie; Lugli, Stefano; Ren, Jinhai; Xiao, Weiyang; Chen, Pan; Tang, Ya

    2016-08-15

    Massive deposition of calcium carbonate in ambient temperature waters (tufa) can form magnificent tufa landscapes, many of which are designated as protected areas. However, tufa landscapes in many areas are threatened by both local anthropogenic activities and climate change. This study, for the first time, posed the question whether the tufa landscape degradation (characterized by tufa degradation and increased biomass of green algae) in Jiuzhaigou National Nature Reserve of China is partially caused by regional air pollution and climate warming. The results indicate that wet deposition (including rain and snow) polluted by anthropogenic SO2, NOx, and NH3 emissions dissolves exposed tufa and may considerably reduce tufa deposition rate and even cause tufa dissolution within shallow waters. These effects of wet deposition on tufa enhanced as pH of wet deposition decreased from 8.01 to 5.06. Annual Volume Weighted Mean concentration of reactive nitrogen (including NH4(+) and NO3(-)) in wet deposition (26.1μmolL(-1)) was 1.8 times of the corresponding value of runoff (14.8μmolL(-1)) and exceeded China's national standard of total nitrogen in runoff for nature reserves (14.3μmolL(-1)), indicating a direct nitrogen fertilization effect of wet deposition on green algae. As water temperature is the major limiting factor of algal growth in Jiuzhaigou and temperature in the top layer (0-5cm) of runoff (depth<1m, no canopy coverage of trees and shrubs) was significantly higher at the sites with increased biomass of green algae (p<0.05), climate warming in this region would favor algal growth. In sum, this study suggests that climate warming and enhanced sulfur and nitrogen deposition have contributed to the current degradation of tufa landscape in Jiuzhaigou, but in order to quantify the contributions, further studies are needed, as many other anthropogenic and natural processes also influence tufa landscape evolution.

  7. Quality-assurance support for the National Atmospheric Deposition Program and National Trends Network monitoring activites: 1987-1990. Interim report

    SciTech Connect

    Bigelow, D.S.; Bennett, B.I.

    1989-02-01

    This report summarizes the quality-assurance activities of the NADP/NTN network from mid-1987 through mid-1988. The report presents some accomplishments and makes recommendations for the network. The report discusses data quality issues relating to site representativeness, field versus laboratory measurements of pH, site operator turnover rates and various monitoring network reviews. The report also contains the previously released NADP/NTN Instruction Manual for Site Operation and the Quality Assurance Report of NADP/NTN Deposition Monitoring for Laboratory Operations as well as an NADP/NTN quality assurance bibliography.

  8. Atmospheric deposition of nitrogen and sulfur in Louisiana

    NASA Astrophysics Data System (ADS)

    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.

  9. Summary report for the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) site-visitation program. Rept. for Oct 88-Sep 89

    SciTech Connect

    Eaton, W.C.; Moore, C.E.; Murdoch, R.W.; Shores, R.C.; Ward, D.A.

    1991-12-01

    The proper collection of precipitation and the accurate measurement of its constituents are important steps in attaining a better understanding of the distribution and effects of acid rain in the United States. One of NAPAP Task Group IV's major programs concerns wet deposition monitoring. One of that program's project, 4A-15, 'Quality Assurance Support for Wet Deposition Monitoring,' is sponsored by the U.S. Environmental Protection Agency (EPA) to evaluate the sample collection process and provide technical assistance to the NADP/NTN network through a site visitation program. Research Triangle Institute, as contractor to EPA, conducts these visits. If deficiencies or nonstandard procedures are noted, the site operator and supervisor are notified. Brief reports are sent to the EPA Project Officer, the NADP/NTN Quality Assurance Manager, and others. In this way, necessary changes can be made promptly. All NADP/NTN sites were visited in 1985-1986. A second round of visits began in October 1986, with the goal of visiting approximately one-third of the 200 sites each year over the next three years. The document is a summary report of the findings from the 1988-1989 (Fiscal Year 1989) site visitation program to 72 of the sites of the NADP/NTN network.

  10. Summary report for the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) site-visitation program for the period October 1989 through September 1990

    SciTech Connect

    Eaton, W.C.; Moore, C.E.; Murdoch, R.W.; Shores, R.C.; Ward, D.A.

    1992-02-01

    The proper collection of precipitation and the accurate measurement of its constituents are important steps in attaining a better understanding of the distribution and effects of acid rain in the United States. One of NAPAP Task Group IV's major programs concerns wet deposition monitoring. One of that program's projects, 4A-15, 'Quality Assurance Support for Wet Deposition Monitoring,' is sponsored by the U.S. Environmental Protection Agency (EPA) to evaluate the sample collection process and provide technical assistance to the NADP/NTN network through a site visitation program. If deficiencies or nonstandard procedures are noted, the site operator and supervisor are notified. All NADP/NTN sites were visited in 1985-1986. A second round of visits began in October 1986, with the goal of visiting approximately one-third of the 200 sites each year over the next three years. The document is a summary report of the findings from the 1989-1990 (Fiscal Year 1990) site visitation program to 67 of the sites of the NADP/NTN network.

  11. Evaluation of National Atmospheric Deposition Program measurements for co-located Sites CO89 and CO98 at Rocky Mountain National Park, 2012

    USGS Publications Warehouse

    ,

    2013-01-01

    Median weekly absolute percent differences for selected parameters including: sample volume, 8.0 percent; ammonium concentration, 9.1 percent; nitrate concentration, 8.5 percent; sulfate concentration, 10.2 percent. Annual precipitation-weighted mean concentrations were higher for CO98 compared to CO89 for all analytes. The chemical concentration record for CO98 contains more valid samples than the CO89 record. Therefore, the CO98 record is more representative of 2012 total annual deposition at Loch Vale. Daily precipitation-depth records for the co-located precipitation gages were 100 percent complete, and the total annual precipitation depths between the sites differed by 0.1 percent for the year (91.5 and 91.4 cm).

  12. MEAD Marine Effects of Atmospheric Deposition

    NASA Astrophysics Data System (ADS)

    Jickells, T.; Spokes, L.

    2003-04-01

    The coastal seas are one of the most valuable resources on the planet but they are threatened by human activity. We rely on the coastal area for mineral resources, waste disposal, fisheries and recreation. In Europe, high population densities and high levels of industrial activity mean that the pressures arising from these activities are particularly acute. One of the main problems concerning coastal seas is the rapid increase in the amounts of nitrogen-based pollutants entering the water. They come from many sources, the most important ones being traffic, industry and agriculture. These pollutants can be used by algae as nutrients. The increasing concentrations of these nutrients have led to excessive growth of algae, some of which are harmful. When algae die and decay, oxygen in the water is used up and the resulting lower levels of oxygen may lead to fish kills. Human activity has probably doubled the amount of chemically and biologically reactive nitrogen present globally. In Europe the increases have been greater than this, leading to real concern over the health of coastal waters. Rivers have, until recently, been thought to be the most important source of reactive nitrogen to the coastal seas but we now know that inputs from the atmosphere are large and can equal, or exceed, those from the rivers. Our initial hypothesis was that atmospheric inputs are important and potentially different in their effect on coastal ecosystems to riverine inputs and hence require different management strategies. However, we had almost no information on the direct effects of atmospheric deposition on marine ecosystems, though clearly such a large external nitrogen input should lead to enhanced phytoplankton growth The aim of this European Union funded MEAD project has been to determine how inputs of nitrogen from the atmosphere affect the chemistry and biology of coastal waters. To try to answer this, we have conducted field experiments in the Kattegat, an area where we know

  13. Atmospheric deposition fluxes to Monetary Bay

    NASA Astrophysics Data System (ADS)

    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.

  14. Investigation of differences between field and laboratory pH measurements of national atmospheric deposition program/national trends network precipitation samples

    USGS Publications Warehouse

    Latysh, N.; Gordon, J.

    2004-01-01

    A study was undertaken to investigate differences between laboratory and field pH measurements for precipitation samples collected from 135 weekly precipitation-monitoring sites in the National Trends Network from 12/30/1986 to 12/28/1999. Differences in pH between field and laboratory measurements occurred for 96% of samples collected during this time period. Differences between the two measurements were evaluated for precipitation samples collected before and after January 1994, when modifications to sample-handling protocol and elimination of the contaminating bucket o-ring used in sample shipment occurred. Median hydrogen-ion and pH differences between field and laboratory measurements declined from 3.9 ??eq L-1 or 0.10 pH units before the 1994 protocol change to 1.4 ??eq L-1 or 0.04 pH units after the 1994 protocol change. Hydrogen-ion differences between field and laboratory measurements had a high correlation with the sample pH determined in the field. The largest pH differences between the two measurements occurred for high-pH samples (>5.6), typical of precipitation collected in Western United States; however low- pH samples (<5.0) displayed the highest variability in hydrogen-ion differences between field and laboratory analyses. Properly screened field pH measurements are a useful alternative to laboratory pH values for trend analysis, particularly before 1994 when laboratory pH values were influenced by sample-collection equipment.

  15. Alkylphenols in atmospheric depositions and urban runoff.

    PubMed

    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

  16. Modeling Atmospheric Energy Deposition (by energetic ions)

    NASA Astrophysics Data System (ADS)

    Parkinson, C. D.; Brain, D. A.; Lillis, R. J.; Liemohn, M. W.; Bougher, S. W.

    2011-12-01

    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. Such modeling has been previously done for Earth, Mars and Jupiter using a guiding center precipitation model with extensive collisional physics. 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 that can perform calculations for cases where there is only a weak or nonexistent magnetic field that includes detailed physical interaction with the atmosphere (i.e. collisional physics). We show initial efforts to apply a full Lorentz motion particle transport model to study the effects of particle precipitation in the upper atmospheres of Venus, Mars, and Titan. A systematic study of the ionization, excitation, and energy

  17. Simple Approaches for Measuring Dry Atmospheric Nitrogen Deposition to Watersheds

    EPA Science Inventory

    Assessing the effects of atmospheric nitrogen (N) deposition on surface water quality requires accurate accounts of total N deposition (wet, dry, and cloud vapor); however, dry deposition is difficult to measure and is often spatially variable. Affordable passive sampling methods...

  18. Atmospheric mercury footprints of nations.

    PubMed

    Liang, Sai; Wang, Yafei; Cinnirella, Sergio; Pirrone, Nicola

    2015-03-17

    The Minamata Convention was established to protect humans and the natural environment from the adverse effects of mercury emissions. A cogent assessment of mercury emissions is required to help implement the Minamata Convention. Here, we use an environmentally extended multi-regional input-output model to calculate atmospheric mercury footprints of nations based on upstream production (meaning direct emissions from the production activities of a nation), downstream production (meaning both direct and indirect emissions caused by the production activities of a nation), and consumption (meaning both direct and indirect emissions caused by final consumption of goods and services in a nation). Results show that nations function differently within global supply chains. Developed nations usually have larger consumption-based emissions than up- and downstream production-based emissions. India, South Korea, and Taiwan have larger downstream production-based emissions than their upstream production- and consumption-based emissions. Developed nations (e.g., United States, Japan, and Germany) are in part responsible for mercury emissions of developing nations (e.g., China, India, and Indonesia). Our findings indicate that global mercury abatement should focus on multiple stages of global supply chains. We propose three initiatives for global mercury abatement, comprising the establishment of mercury control technologies of upstream producers, productivity improvement of downstream producers, and behavior optimization of final consumers.

  19. Atmospheric mercury footprints of nations.

    PubMed

    Liang, Sai; Wang, Yafei; Cinnirella, Sergio; Pirrone, Nicola

    2015-03-17

    The Minamata Convention was established to protect humans and the natural environment from the adverse effects of mercury emissions. A cogent assessment of mercury emissions is required to help implement the Minamata Convention. Here, we use an environmentally extended multi-regional input-output model to calculate atmospheric mercury footprints of nations based on upstream production (meaning direct emissions from the production activities of a nation), downstream production (meaning both direct and indirect emissions caused by the production activities of a nation), and consumption (meaning both direct and indirect emissions caused by final consumption of goods and services in a nation). Results show that nations function differently within global supply chains. Developed nations usually have larger consumption-based emissions than up- and downstream production-based emissions. India, South Korea, and Taiwan have larger downstream production-based emissions than their upstream production- and consumption-based emissions. Developed nations (e.g., United States, Japan, and Germany) are in part responsible for mercury emissions of developing nations (e.g., China, India, and Indonesia). Our findings indicate that global mercury abatement should focus on multiple stages of global supply chains. We propose three initiatives for global mercury abatement, comprising the establishment of mercury control technologies of upstream producers, productivity improvement of downstream producers, and behavior optimization of final consumers. PMID:25723898

  20. Acid deposition: a national problem

    SciTech Connect

    Hendrey, G.R.

    1985-01-01

    The deposition of excessive quantities of sulfur and nitrogen from the atmosphere constitutes a problem encompassing all of the United States east of the Mississippi River. It also occurs in some areas of the western US. Calculations based on emission inventories and simplifying assumptions indicate electric utilities account for 66% of SO/sub 2/ emissions, 29% of NO/sub x/ emissions and about half of precipitation acidity. Acidification of clearwater lakes and streams is a widespread problem only in areas receiving rain with an average acidity less than or equal to 4.7. The dominant anion in such waters is SO/sub 4//sup 2 -/ and concentrations of aluminum derived from watershed acidification may exceed 200 ..mu..g 1/sup -1/. Changes in assemblages of aquatic biota become increasingly apparent as pH decreases below 6.0, and elimination of fish from some waters has been documented. The sensitivity of surface waters is controlled by and represents an integration of biogeochemical processes in their edaphic settings. Changes in surface water chemistry imply changes in the terrestrial environment. Direct evidence of changes in terrestrial environments is sparse. Nevertheless, observations of forest dieback in the US and abroad suggest that acid deposition may contribute to the problem. Very few credible studies are available which allow an evaluation of acid precipitation effects on crops.

  1. Atmospheric Transport and Deposition of Agricultural Chemicals

    NASA Astrophysics Data System (ADS)

    Majewski, M. S.; Vogel, J. R.; Capel, P. D.

    2006-05-01

    Concentrations of more than 80 pesticides and select transformation products were measured in atmospheric deposition during two growing seasons in five agricultural areas across the United States. Rainfall samples were collected at study areas in California, Indiana, Maryland, and Nebraska. In the arid Yakima Valley of Washington, dry deposition for the same compounds was estimated using air concentration measurements and depositional models. In the predominantly corn, soybean, and alfalfa growing region of Nebraska, Indiana, and Maryland, the herbicides acetochlor, alachlor, atrazine, and metolachlor where the predominant pesticides detected, and the highest concentrations ranged from 0.64 microgram per liter (ug/L) for metolachlor in a small, predominantly dairy use dominated watershed in Maryland to 6.6 ug/L and 19 ug/L for atrazine in Indiana and Nebraska, respectively. California showed a different seasonal occurrence pattern and suite of detected pesticides because the rainy season occurs during the winter months and a wide variety of crops are grown throughout the year. With the exception of metolachlor (0.23 ug/L, max.), the corn and soybean herbicides were not used to any great extent in the California study area and were not detected. The insecticides diazinon (1.21 ug/L, max.) and chlorpyrifos (0.12 ug/L, max.) were detected in nearly every sample taken in California. The Washington study area was similar to California in terms of the variety of crops grown and the pesticides use, but it receives very little rainfall. Dry deposition was estimated at this site from air concentrations and particle settling velocities. The results of these studies show the importance of the atmosphere as an additional source of pesticide loading to agricultural watersheds.

  2. Energy Deposition Processes in Titan's Upper Atmosphere

    NASA Technical Reports Server (NTRS)

    Sittler, Edward C., Jr.; Bertucci, Cesar; Coates, Andrew; Cravens, Tom; Dandouras, Iannis; Shemansky, Don

    2008-01-01

    Most of Titan's atmospheric organic and nitrogen chemistry, aerosol formation, and atmospheric loss are driven from external energy sources such as Solar UV, Saturn's magnetosphere, solar wind and galactic cosmic rays. The Solar UV tends to dominate the energy input at lower altitudes of approximately 1100 km but which can extend down to approximately 400 km, while the plasma interaction from Saturn's magnetosphere, Saturn's magnetosheath or solar wind are more important at higher altitudes of approximately 1400 km, but the heavy ion plasma [O(+)] of approximately 2 keV and energetic ions [H(+)] of approximately 30 keV or higher from Saturn's magnetosphere can penetrate below 950km. Cosmic rays with energies of greater than 1 GeV can penetrate much deeper into Titan's atmosphere with most of its energy deposited at approximately 100 km altitude. The haze layer tends to dominate between 100 km and 300 km. The induced magnetic field from Titan's interaction with the external plasma can be very complex and will tend to channel the flow of energy into Titan's upper atmosphere. Cassini observations combined with advanced hybrid simulations of the plasma interaction with Titan's upper atmosphere show significant changes in the character of the interaction with Saturn local time at Titan's orbit where the magnetosphere displays large and systematic changes with local time. The external solar wind can also drive sub-storms within the magnetosphere which can then modify the magnetospheric interaction with Titan. Another important parameter is solar zenith angle (SZA) with respect to the co-rotation direction of the magnetospheric flow. Titan's interaction can contribute to atmospheric loss via pickup ion loss, scavenging of Titan's ionospheric plasma, loss of ionospheric plasma down its induced magnetotail via an ionospheric wind, and non-thermal loss of the atmosphere via heating and sputtering induced by the bombardment of magnetospheric keV ions and electrons. This

  3. Atmospheric mass deposition by captured planetesimals

    NASA Astrophysics Data System (ADS)

    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.

  4. Atmospheric wet deposition of mercury in North America

    SciTech Connect

    Sweet, C.W.; Prestbo, E.; Brunette, B.

    1999-07-01

    Currently, 39 states in the US and 5 Canadian provinces have issued advisories about the dangers of eating mercury-contaminated fish taken from waters within their boundaries. The problem is most severe in the Great Lakes region, the Northeast US states, the Canadian maritime provinces, and in south Florida where many lakes and streams contain fish with concentrations of 1 ppm or higher. For many rural and remote locations, atmospheric deposition is the primary source of mercury. In 1995, the National Atmospheric Deposition Program (NADP) initiated a program to monitor total mercury and methylmercury (MMHg) in wet deposition (rain and snow) in North America. In this program, the Mercury Deposition Network (MDN), individual monitoring sites are funded and operated by a variety of local, state, and federal agencies. However, sampling and analysis are coordinated through a central laboratory so that all of the samples are collected and analyzed using the same protocols. Weekly wet-only precipitation samples are collected using an all-glass sampling train and special handling techniques. Analysis is by cold vapor atomic fluorescence spectrometry using USEPA Method 1631 for total mercury. Nearly 40 MDN sites are in operation in 1999. Most of the sites are in the eastern US and Canada. During 1996 and 1997, the volume-weighted mean concentration of total mercury in precipitation collected at 22 sites ranged from 6.0 to 18.9 ng/L. Annual deposition varied between 2.1 and 25.3 {micro} g/m{sup 2}. The average weekly wet deposition of total mercury is more than three times higher in the summer (June-August) than in the winter (December-February). This increase is due to both higher amounts of precipitation and higher concentrations of mercury in precipitation during the summer. The highest values for mercury concentration in precipitation and wet deposition of mercury were measured in the southeastern US.

  5. Atmospheric mercury deposition to Lake Michigan during the Lake Michigan Mass Balance Study.

    PubMed

    Landis, Matthew S; Keeler, Gerald J

    2002-11-01

    Wet and dry mercury (Hg) deposition were calculated to Lake Michigan using a hybrid receptor modeling framework. The model utilized mercury monitoring data collected during the Lake Michigan Mass Balance Study and the Atmospheric Exchange Over Lakes and Oceans Studytogether with high-resolution over-water meteorological date provided by the National Oceanic and Atmospheric Administration (July, 1994-October, 1995). Atmospheric deposition was determined to be the primary pathway for mercury inputto Lake Michigan, contributing approximately 84% of the estimated 1403 kg total annual input (atmospheric deposition + tributary input). Wet (10.6 microg m(-2)) and dry deposition (9.7 microg m(-2)) contributed almost equally to the annual atmospheric Hg deposition of 20.3 microg m(-2) (1173 kg). Re-emission of dissolved gaseous Hg from the lake was also significant (7.8 microg m(-2)), reducing the net atmospheric deposition to 12.5 microg m(-2) (720 kg). A strong urban influence was observed in the over-water mercury deposition estimates in the southern portion of the lake. The Chicago/Gary urban area was estimated to contribute approximately 20% (127 kg) of the annual atmospheric mercury deposition to Lake Michigan. The magnitude of local anthropogenic mercury sources in the Chicago/Gary urban area suggests that emission reductions could significantly reduce atmospheric mercury deposition into Lake Michigan.

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

    USGS Publications Warehouse

    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

  7. 77 FR 15358 - National Oceanic and Atmospheric Administration

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-15

    ... National Oceanic and Atmospheric Administration Availability of Seats for the Monitor National Marine...), National Oceanic and Atmospheric Administration (NOAA), Department of Commerce (DOC). ACTION: Notice and..., National Ocean Service, National Oceanic and Atmospheric Administration. BILLING......

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

    USGS Publications Warehouse

    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

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

    PubMed Central

    Skarżyńska, K.; Polkowska, Ż; Namieśnik, J.

    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. PMID:17671615

  10. Variation of wet deposition chemistry in Sequoia National Park, California

    USGS Publications Warehouse

    Stohlgren, Thomas J.; Parsons, David J.

    1987-01-01

    Sequoia National Park has monitored wet deposition chemistry in conjunction with the National Atmospheric Deposition Program and National Trends Network (NADP/NTN), on a weekly basis since July, 1980. Annual deposition of H, NO3 and SO4 (0.045, 3.6, and 3.9 kg ha−1 a−1, respectively) is relatively low compared to that measured in the eastern United States, or in the urban Los Angeles and San Francisco areas. Weekly ion concentrations are highly variable. Maximum concentrations of 324,162, and 156 μeq ol−1 of H, NO3 and SO4 have been recorded for one low volume summer storm (1.4 mm). Summer concentrations of NO3 and SO4 average two and five times higher, respectively, than concentrations reported for remote areas in the world. There is considerable variability in the ionic concentration of low volume samples, and much less variability in moderate and high volume samples.

  11. Atmospheric transport and deposition of acidic air pollutants

    SciTech Connect

    Murphy, C.E. Jr.

    1981-01-01

    Although general principles which govern atmospheric chemistry of sulfur are understood, a purely theoretical estimation of the magnitude of the processes is not likely to be useful. Furthermore, the data base necessary to make empirical estimates does not yet exist. The sulfur budget of the atmosphere appears to be dominated by man-associated sulfur. The important processes in deposition of man-associated sulfur are wet deposition of sulfate and dry deposition of SO/sub 2/. The relative importance of sulfate and SO/sub 2/ to sulfur deposition (input to watersheds) depends on the air concentrations, and either compound may be the greater contributor depending on conditions. (PSB)

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

    EPA Science Inventory

    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...

  13. [Basic features and monitoring methodologies of atmospheric nitrogen deposition].

    PubMed

    Song, Huan-Huan; Jiang, Chun-Ming; Yu, Wan-Tai

    2014-02-01

    Atmospheric nitrogen (N) deposition, including dry and wet deposition, is an important inorganic and organic N source for ecosystems, and also a key link of the N biogeochemical cycle. Recently, considerable active nitrogen has been emitted into the atmosphere due to enhanced human activities. High N emission leads to high deposition which has caused a series of environment risks, and more attentions have been focused on this issue. This article gave an overview of the basic content about the present N deposition research, such as the component, process, spatial and temporal variation, as well as ecological effect. Then the sampling methods of wet and dry deposition in the field, analysis methods in laboratory and primary techniques of N source identification were summarized. The N deposition research trend in the future was emphasized.

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

    PubMed

    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.

  15. Dry and Wet Atmospheric Nitrogen Deposition in Africa

    NASA Astrophysics Data System (ADS)

    Galy-Lacaux, C.; Al Ourabi, H.; Lacaux, J. P.; Gardrat, E.; Mphepya, J.; Pienaar, K.

    2003-04-01

    This work is part of the IDAF* (IGAC/DEBITS/AFrica) programme which started in 1995 with the establishment of 10 measurement sites representative of major African ecosystems. The objectives of the programme are to study dry and wet deposition of important trace species and more generally the biogeochemical cycles of key nutrients. In this way, the IDAF activity is based on high quality measurements of atmospheric chemical data (gaseous, precipitation and aerosols chemical composition) on the basis of a multi-year monitoring. In this paper, our objective is to present the first estimation of the atmospheric nitrogen deposition budget in Africa based on experimental measurements. To estimate atmospheric nitrogen deposition, including both wet and dry processes, we compiled the IDAF nitrogen data (rain, particles and gases) obtained from the network for three consecutive years: 1998, 1999 and 2000. In western and central Africa, we studied a transect going from dry savanna (Niger and Mali) to humid savanna (Ivory Coast and Central Republic of Africa) and forest (Congo and Cameroon). In South Africa, two IDAF very different sites were chosen to be representative on one hand of a rural (semi-arid savanna) and on the other hand of an industrialized site. Presenting the different components of the nitrogen atmospheric deposition on these sites, i.e, dry deposition in gaseous (NO2, NH3, HNO3) and particulate forms (pNH4+, pNO3-) associated with wet deposition (NH4+, NO3-), this study allows us to give the relative contribution of dry and wet deposition processes to the total nitrogen deposition. The nitrogen atmospheric deposition presented for all the IDAF sites of the african continent range from 8 to 19 kgN.ha-1.yr-1. Sites from dry savanna in South Africa and West Africa have similar values (around 8-9 kgN.ha-1.yr-1 ) which are found in the lower part of the range. Wet zones from savanna and forests give values in the upper range (15 to 19 kgN.ha-1.yr-1). The

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

    PubMed

    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 < 0.05). The three nitrogen 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

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

    NASA Astrophysics Data System (ADS)

    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.

  18. National Oceanic and Atmospheric Administration

    NASA Astrophysics Data System (ADS)

    Mockler, Susan Bucci

    Although slightly reduced from the 1994 funding level of $2 billion, James Baker, under secretary for Oceans and Atmosphere at NOAA, said they are “pleased with the numbers.” The total request for 1995 of $1.96 billion includes some new programmatic funds, and the decrease from fiscal 1994 reflects, in part, some one-time projects in last year's budget, Baker said. NOAA's budget request for 1995 is driven by its strategic plan, which was established in 1993 to unify the agency, identify coherent objectives that capitalize on available resources across NOAA's program elements, and develop implementation measures to maximize cost-effectiveness. The strategic plan organizes NOAA's program responsibilities into two broad “portfolios”—Environmental Stewardship and Environmental Assessment and Prediction, and two other priorities—Cross-Cut Programs and Infrastructure.

  19. Atmospheric corrosion and chloride deposition on metal surfaces

    SciTech Connect

    Matthes, Steven A.; Holcomb, Gordon R.; Cramer, Stephen D.; Covino, Bernard S., Jr.; Bullard, Sophie J.

    2004-01-01

    Atmospheric corrosion and chloride deposition on metal surfaces was studied at an unpolluted coastal (marine) site, an unpolluted rural inland site, and a polluted urban site. Chloride deposition by both wet (precipitation) and dry deposition processes over a multi-year period was measured using ion chromatography analysis of incident precipitation and precipitation runoff from the surface of metal samples. Chloride deposition was measured on zinc, copper, lead, mild steel, and non-reactive blank panels, as well as two panels coated with thermal-sprayed zinc alloys. Chloride deposition measured by runoff chemistry was compared with chloride deposition measurements made by the ASTM wet candle technique. Corrosion mass loss as a function of distance from the ocean is presented for copper and mild steel in bold exposures on the west coast.

  20. Atmospheric transport of iron and its deposition in the ocean

    SciTech Connect

    Duce, R.A.; Tindale, N.W. )

    1991-12-01

    The atmospheric transport of continental weathering products is responsible for much of the mineral material and Fe entering the open ocean and is probably the dominant source of nutrient Fe in the photic zone. In regions where other nutrients are present in high concentrations, the flux of Fe from the atmosphere may be a limiting factor in primary productivity. Due to the larger source regions for dust north of the equator, {approximately}8 times more atmospheric Fe is deposited in the northern hemisphere than in the southern hemisphere. The mineral aerosol and Fe transport and deposition are highly variable due to the episodic nature of dust generation and its transport and deposition processes. Between 10 and 50% of the total atmospheric Fe entering the world ocean appears to dissolve rapidly when the mineral matter enters the ocean. Much of the atmospheric Fe is present as Fe(II), apparently produced as a result of photochemical reduction reactions taking place during atmospheric transport. This readily soluble Fe(II) should be available immediately for use as a nutrient by phytoplankton. Atmospheric transport from the continents is estimated to supply {approximately}3 times as much dissolved Fe to the oceans as that delivered via rivers.

  1. SENSITIVITY OF THE NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION MULTILAYER MODEL TO INSTRUMENT ERROR AND PARAMETERIZATION UNCERTAINTY

    EPA Science Inventory

    The response of the National Oceanic and Atmospheric Administration multilayer inferential dry deposition velocity model (NOAA-MLM) to error in meteorological inputs and model parameterization is reported. Monte Carlo simulations were performed to assess the uncertainty in NOA...

  2. 77 FR 33443 - National Oceanic and Atmospheric Administration

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-06

    ... National Oceanic and Atmospheric Administration Pacific Fishery Management Council; Public Meeting AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce... Assessment Methods for Data-Moderate Stocks will be held at the National Marine Fisheries Service's...

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Potential for atmospheric deposition of bacteria to influence bacterioplankton communities.

    PubMed

    Jones, Stuart E; Newton, Ryan J; McMahon, Katherine D

    2008-06-01

    Biogeographic patterns in microbial communities are an exciting but controversial topic in microbial ecology. Advances in theory pertaining to assembly of microbial communities have made strong assumptions about dispersal of bacteria without exploration. For this reason, we investigated rates of atmospheric bacterial deposition and compared the taxonomic composition of bacteria in rain with that of common freshwater bacterial communities. Our findings suggest that it is not appropriate to take for granted that atmospheric deposition of bacteria is a significant vector of immigration to freshwater ecosystems.

  6. Puff-Plume Atmospheric Deposition Model.

    1992-06-24

    Version: 00 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 ofmore » 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. Data files are provided for demonstration. The software for archiving the required on-line meteorological data is not included. Subroutines used for graphic display of results and operational control of the DEC VT100 and Tektronix terminals in the terminal network are included. Anyone wishing t use these routines must make appropriate modifications to the file TERMINALS.DAT. The DAT files provided were copied during the afternoon of December 28, 1983. Test runs attempting to use these files should specify release times on or before that date. Any user wishing to obtain numerical output only form the model based on conditions in his locality must supply appropriate wind data for the program.« less

  7. An automatic collector to monitor insoluble atmospheric deposition: application for mineral dust deposition

    NASA Astrophysics Data System (ADS)

    Laurent, B.; Losno, R.; Chevaillier, S.; Vincent, J.; Roullet, P.; Bon Nguyen, E.; Ouboulmane, N.; Triquet, S.; Fornier, M.; Raimbault, P.; Bergametti, G.

    2015-07-01

    Deposition is one of the key terms of the mineral dust cycle. However, dust deposition remains poorly constrained in transport models simulating the atmospheric dust cycle. This is mainly due to the limited number of relevant deposition measurements. This paper aims to present an automatic collector (CARAGA), specially developed to sample the total (dry and wet) atmospheric deposition of insoluble dust in remote areas. The autonomy of the CARAGA can range from 25 days to almost 1 year depending on the programmed sampling frequency (from 1 day to 2 weeks respectively). This collector is used to sample atmospheric deposition of Saharan dust on the Frioul islands in the Gulf of Lions in the Western Mediterranean. To quantify the mineral dust mass in deposition samples, a weighing and ignition protocol is applied. Almost 2 years of continuous deposition measurements performed on a weekly sampling basis on Frioul Island are presented and discussed with air mass trajectories and satellite observations of dust. Insoluble mineral deposition measured on Frioul Island was 2.45 g m-2 for February to December 2011 and 3.16 g m-2 for January to October 2012. Nine major mineral deposition events, measured during periods with significant MODIS aerosol optical depths, were associated with air masses coming from the southern Mediterranean Basin and North Africa.

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

    PubMed

    Costanza, Jennifer K; Marcinko, Sarah E; Goewert, Ann E; Mitchell, Charles E

    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(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(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(3) yr(-1), 73% of which originates from the Coastal Plain. Stronger waste management and emission standards for CAFOs, particularly those on the Coastal Plain nearest to sensitive water

  9. Modeling Atmospheric Deposition across the Northeastern U.S. and its Potential Effects on Forest Albedo

    NASA Astrophysics Data System (ADS)

    Haddad, D. M.; Ollinger, S. V.; Jenkins, J.; Martin, M.

    2009-12-01

    In 1993 Ollinger did a study to model Atmospheric Deposition across the Northeastern U.S. My project was to update the model to see if the atmospheric deposition concentration or trends have changed in the past 16 year. I also drew a connection to some of Ollinger’s more recent work where he studied the nitrogen content in leaves and its effects on carbon uptake and forest albedo. From his study in 2008 he found that an increase in the nitrogen content in the leaves leads to increased carbon uptake and an increase in short wave albedo. I was hypothesizing that nitrogen deposition acts as an input of nitrogen into the ecosystem, so if you increased the nitrogen deposition the nitrogen content in the leaves would increase as well. This should mean that with greater nitrogen deposition you have a higher short wave albedo. So the second goal of my study was to see if there is a relationship between nitrogen deposition and short wave albedo. I used data from NADP (National Atmospheric Deposition Sites), CASTNET (Clean Air Status and Trends Network sites), and NOAA weather stations to model wet deposition, dry deposition, and rainfall by the latitude, longitude, and elevation of the sites in the Northeastern US. I found a trend between wet deposition and longitude, as you head east in the region the wet deposition decreases. We believe this is because wet deposition reflects long distance pollution transport from major pollution sources to the west of the study region, like power plants in the Great Lakes Region. I then found a trend between dry deposition and latitude, as you head north in the region the dry deposition decreases. This we believe is because dry deposition reflects more local pollution sources, like the concentration of urban areas along the southern coast of the region. With precipitation I found a trend with latitude, longitude, and elevation. The most important fact is that rainfall is greater along the coast and at higher elevations. Then I compared

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    Ecological effects of elevated atmospheric N deposition for high elevation lakes of the western and northeastern US include nutrient enrichment and acidification. These effects are most evident in high elevation lakes, which are sensitive to atmospheric deposition and have been minimally impacted by land disturbance. Nitrogen-limited lakes will exhibit increases in productivity and shifts in the composition of phytoplankton in response to increases in atmospheric N deposition. Wet N deposition reported by NADP/NTN does not accurately depict total N deposition including dry species, and national NADP maps can misrepresent total deposition amounts in regions of complex terrain, so we calculated N deposition three different ways in order to explore critical loads. The nutrient enrichment critical load for Western lakes ranged 1.0-3.0 kg N per ha per yr, reflecting near-lack of watershed vegetation in complex, snow-melt dominated terrain. The nutrient enrichment critical load for Northeastern lakes ranged 3.5-6.0 kg N per ha per yr. 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 yr (western) and 8.0 kg N per ha per yr (northeastern). Empirical critical loads for N-caused acidification were difficult to determine due to lack of observations in the West, and because of the additive effects of decades of atmospheric sulfur deposition in the Northeast. For both nutrient enrichment and acidification, the N critical load was a function of how atmospheric N deposition was determined.

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

    USGS Publications Warehouse

    Stacey, Paul E.; Greening, Holly; Kremer, James N.; Peterson, David; Tomasko, David A.; Valigura, Richard A.; Alexander, Richard B.; Castro, Mark S.; Meyers, Tilden P.; Paerl, Hans W.; Stacey, Paul E.; Turner, R. Eugene

    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.

  12. Impact of crustal elements on global atmospheric deposition of Nitrogen

    NASA Astrophysics Data System (ADS)

    Myriokefalitakis, Stelios; Daskalakis, Nikos; Kanakidou, Maria

    2014-05-01

    Nitrogen deposition plays a significant role in ecosystem functioning and particularly in ocean productivity. Chemical transformations occurring in all phases present in the atmosphere, affect the solubility of reactive nitrogen pool and thus of N-deposition. A significant fraction of N-deposition occurs in the form of particulate matter (PM) deposition. Atmospheric PM is composed of water, inorganic salts, crustal material, organics and trace metals. Important contributors to the dry fine PM are inorganic compounds like ammonium (NH4+), and nitrate (NO3-), sodium (Na+), sulfate (SO4=) and bisulfate (HSO4-). Crustal species like Ca2+, K+, Mg2+ are major components of dust and can neutralize part of the acidity of the atmosphere (e.g. NO3-, SO4=). Their presence is thus affecting the partitioning of NO3-, SO4= and NH4+ on atmospheric PM as well as N-solubility and deposition, especially in areas where dust comprises a significant portion of total PM such as the Mediterranean region. The effect of crustal material on N-containing species deposition is here investigated using the global TM4-ECPL global chemistry-transport model that is able to simulate oxidant chemistry, accounting for non-methane volatile organic compounds and all major aerosol components, including secondary aerosols like sulfate, nitrate and secondary organic aerosols. The model also accounts for multiphase chemistry in clouds and aerosol water. Gas-particle partitioning of inorganic and crustal components is solved using the ISORROPIA II aerosol thermodynamics model. Global simulations have been performed considering and neglecting crustal material for the partitioning of HNO3/NO3 and H2SO4/SO4=. Differences between the N-deposition amounts and their solubility are presented and thoroughly discussed.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. REGIONAL MODELING OF THE ATMOSPHERIC TRANSPORT AND DEPOSITION OF ATRAZINE

    EPA Science Inventory

    A version of the Community Multiscale Air Quality (CMAQ) model has been developed by the U.S. EPA that is capable of addressing the atmospheric fate, transport and deposition of some common trace toxics. An initial, 36-km rectangular grid-cell application for atrazine has been...

  15. A summary of the Lake Tahoe Atmospheric Deposition Study (LTADS)

    NASA Astrophysics Data System (ADS)

    Dolislager, Leon J.; VanCuren, Richard; Pederson, James R.; Lashgari, Ash; McCauley, Eileen

    2012-01-01

    The Lake Tahoe Atmospheric Deposition Study (LTADS) was conducted by the California Air Resources Board (CARB) primarily to generate refined estimates of the atmospheric deposition of nitrogen (N), phosphorous (P), and particulate matter (PM) directly to Lake Tahoe, which straddles the boundary between the states of California and Nevada in the United States of America. LTADS estimated that approximately 185, 3, and 755 metric tons respectively of N, P, and PM being directly deposited to the lake from the atmosphere. Various measurements of emissions, meteorology, and air quality were made within and west (typically upwind) of the Lake Tahoe Air Basin to better understand the pollutant sources contributing to the atmospheric deposition. The data indicate that ammonia (NH 3) contributes the bulk of the N loading. Aerosols with diameters greater than 2.5 μm contribute the bulk of the P and PM mass loadings. The emission sources of P and PM appear to be primarily local and associated with motor vehicles. However, construction, fires, and natural sources also contribute to the pollutant loadings. LTADS was part of a much larger research program to guide efforts to restore the remarkable water clarity of Lake Tahoe.

  16. ANALYSIS OF ATMOSPHERE DEPOSITION SAMPLES FROM EASTON, PA

    EPA Science Inventory

    The report gives results of an analysis of samples of tenacious atmospheric deposits on exposed surfaces (e.g., automobiles and houses) in an industrial area near Easton, PA. The analysis was made at the request of the State of Pennsylvania. The Pennsylvania Department of Environ...

  17. Atmospheric deposition of nitrogen: Potential benefits to agricultural production

    SciTech Connect

    Coveney, E.A.; Medeiros, W.H.; Moskowitz, P.D.

    1986-11-01

    Effects of indirect fertilization on agricultural lands by atmospheric deposition are examined for the four most valuable crops in the US: corn, soybean, wheat, and pasture grasses. A literature search was conducted to find suitable dose-response functions for the effects of fertilization on yield of each crop. Predicted yield changes were computed from the deposition of nitrogen to the soil in addition to nitrogen applied in accordance with current agronomic practices using these dose-response functions. Low to high nitrogen inputs from atmospheric deposition (1 to 7 kg/ha) are expected to increase the average yield of corn by 0.2 to 1.1%, soybean by 0.1 to 0.7%, wheat by 0.1 to 0.4%, and pasture grasses by 1.6 to 14%. Pasture land is predicted to receive the greatest impact because it is usually unfertilized.

  18. Sources of nitrogen in three watersheds of northern Florida, USA: Mainly atmospheric deposition

    SciTech Connect

    Fu, Ji-Meng; Winchester, J.W. )

    1994-03-01

    Atmospheric deposition is estimated to be the principal source of N in water that flows to the Apalachicola river from the Chattahoochee and Flint Rivers (ACF) as well as in two nearby small rivers, Ochlockonee (Och) and Sopchoppy (Sop), that drain watersheds with different land use characteristics. By mass balance and descriptive statistics of hundreds of rainfall and river water samples from monitoring programs since the 1960s, the average nitrate and ammonium deposition flux from the atmosphere is sufficient to account for N that flows toward Apalachicola Bay, an estuary in which N may be a limiting nutrient. Urban and agricultural sources of N in the three watersheds ACF, Och, and Sop appear to be relatively smaller. The work was based on long-term data bases from the National Atmospheric Deposition Program (NADP) rain chemistry monitoring network and the U.S. Geological Survey (USGS) water monitoring program. Average atmospheric N depositions to the three river watersheds are nearly the same as river fluxes of N in all forms monitored. Nitrogen is not likely to be a limiting nutrient in the three watersheds, since river water N:P exceeds the Redfield ratio. An estimate of largest possible input of urban sewage is several times lower than the atmospheric flux of N to the ACF watershed. And N from N-fertilizer, comparable to the atmospheric deposition flux of N, is likely to be smaller if mostly retained in crops or farmland before it reaches the estuary. Annual nitrogen export from the Apalachicola River to the estuary, 1.22 x 10[sup 9] moles N yr[sup [minus]1], consists of organic nitrogen 60%, nitrate 34%, and NH[sup +][sub 4]6%. Atmospheric nitrate and sulfate depositions are highly correlated, both being principally from fossil fuel combustion. Hydrologic conditions, which exhibit variations on seasonal and longer time scales, play an important role in the transport of nutrients and other species in the rivers.

  19. Sources of nitrogen in three watersheds of northern Florida, USA: Mainly atmospheric deposition

    NASA Astrophysics Data System (ADS)

    Fu, Ji-Meng; Winchester, John W.

    1994-03-01

    Atmospheric deposition is estimated to be the principal source of N in water that flows to the Apalachicola River from the Chattahoochee and Flint Rivers (ACF) as well as in two nearby small rivers, Ochlockonee (Och) and Sopchoppy (Sop), that drain watersheds with different land use characteristics. By mass balance and descriptive statistics of hundreds of rainfall and river water samples from monitoring programs since the 1960s, the average nitrate and ammonium deposition flux from the atmosphere is sufficient to account for N that flows toward Apalachicola Bay, an estuary in which N may be a limiting nutrient. Urban and agricultural sources of N in the three watersheds ACF, Och and Sop appear to be relatively smaller. The work was based on long-term data bases from the National Atmospheric Deposition Program (NADP) rain chemistry monitoring network and the U.S. Geological Survey (USGS) water monitoring program. Average atmospheric N depositions to the three river watersheds are nearly the same as river fluxes of N in all forms monitored. Nitrogen is not likely to be a limiting nutrient in the three watersheds, since river water N:P exceeds the Redfield ratio. An estimate of largest possible input of urban sewage is several times lower than the atmospheric flux of N to the ACF watershed. And N from N-fertilizer, comparable to the atmospheric deposition flux of N, is likely to be smaller if mostly retained in crops or farmland before it reaches the estuary. Annual nitrogen export from the Apalachicola River to the estuary, 1.22 × 10 9 moles N yr -1, consists of organic nitrogen 60%, nitrate 34% and NH 4+ 6%. Atmospheric nitrate and sulfate depositions are highly correlated, both being principally from fossil fuel combustion. Hydrologie conditions, which exhibit variations on seasonal and longer time scales, play an important role in the transport of nutrients and other species in the rivers.

  20. Atmospheric nitrogen deposition promotes carbon loss from peat bogs.

    PubMed

    Bragazza, Luca; Freeman, Chris; Jones, Timothy; Rydin, Håkan; Limpens, Juul; Fenner, Nathalie; Ellis, Tim; Gerdol, Renato; Hájek, Michal; Hájek, Tomás; Iacumin, Paola; Kutnar, Lado; Tahvanainen, Teemu; Toberman, Hannah

    2006-12-19

    Peat bogs have historically represented exceptional carbon (C) sinks because of their extremely low decomposition rates and consequent accumulation of plant remnants as peat. Among the factors favoring that peat accumulation, a major role is played by the chemical quality of plant litter itself, which is poor in nutrients and characterized by polyphenols with a strong inhibitory effect on microbial breakdown. Because bogs receive their nutrient supply solely from atmospheric deposition, the global increase of atmospheric nitrogen (N) inputs as a consequence of human activities could potentially alter the litter chemistry with important, but still unknown, effects on their C balance. Here we present data showing the decomposition rates of recently formed litter peat samples collected in nine European countries under a natural gradient of atmospheric N deposition from approximately 0.2 to 2 g.m(-2).yr(-1). We found that enhanced decomposition rates for material accumulated under higher atmospheric N supplies resulted in higher carbon dioxide (CO2) emissions and dissolved organic carbon release. The increased N availability favored microbial decomposition (i) by removing N constraints on microbial metabolism and (ii) through a chemical amelioration of litter peat quality with a positive feedback on microbial enzymatic activity. Although some uncertainty remains about whether decay-resistant Sphagnum will continue to dominate litter peat, our data indicate that, even without such changes, increased N deposition poses a serious risk to our valuable peatland C sinks.

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

    PubMed

    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.

  2. Atmospheric deposition and critical loads for nitrogen and metals in Arctic Alaska: Review and current status

    USGS Publications Warehouse

    Linder, Greg L.; 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.

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

    USGS Publications Warehouse

    Linder, Greg L.; 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.

  4. Atmospheric deposition of toxics onto Massachusetts Bay—I. Metals

    NASA Astrophysics Data System (ADS)

    Golomb, D.; Ryan, D.; Eby, N.; Underhill, J.; Zemba, S.

    Wet and dry atmospheric deposition of toxic metals was measured at biweekly intervals for one year, from i5 September i992 to i6 September i993 at two sites on Massachusetts Bay, Nahant, near Boston and Truro, near the tip of Cape Cod. Wet and dry deposition was measured using a conventional wet/dry collector, except that the dry bucket contained a layer of water in order to simulate the uptake of dry deposition onto a water surface. In addition, at Nahant, a dichotomous particle collector was used to measure metal concentrations on particles. Analytical methods were INAA and ICP-MS. Generally, dry deposition of metals was greater at Nahant than at Truro, and wet deposition was greater or equal at Truro than at Nahant. Averaging results from the two sites, the following deposition rates (wet + dry) were obtained for the Bay in μg m -2 yr -1: Al i02000, As i32, Cd 405, Co 58, Cr 2700, Cu 3500, Fe 140,000, Mn 4420, Ni 7200, Pb 2700, Sb i60, Se 264, Zn 7800. Preliminary results are also given for mercury wet deposition, which was measured for 6 weekly periods in the fall of 1993.

  5. Atmospheric deposition of phosphorus to land and freshwater.

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Marine N inventory sensitivity to atmospheric N deposition

    NASA Astrophysics Data System (ADS)

    Landolfi, Angela; Somes, Chris; Zamora, Lauren; Koeve, Wolfgang; Oschlies, Andreas

    2015-04-01

    The marine inventory of fixed nitrogen (N), an essential nutrient controlling productivity, is determined by the balance between N2 fixation by cyanobacteria and N-loss via microbially-mediated processes under low oxygen conditions. Human-driven perturbations of ocean temperature and atmospheric N deposition impact on the magnitude of N-loss and N-gain with potential effects on oceanic N2O emissions. However, the timescale and the net effect of these changes on the N inventory is not known. This is particularly so since the degree of coupling between the major source and sink of N is debated and the sign of the feedbacks among these two opposite processes is not well defined. Here we use a global biogeochemical model to investigate how projected changes in ocean warming and atmospheric N deposition may impact the marine N inventory and affect future N2O emissions.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Atmospheric Nitrate Deposition: a Large Nutrient Source in North Florida Watersheds

    NASA Astrophysics Data System (ADS)

    Fu, Jimeng

    Dry deposition of nitrate, estimated from a box model based on NO_{x} emissions and rain chemistry monitoring data over the contiguous 48 states, accounts for about half of the total US NO_{x} emissions, a deposition flux twice that of measured wet deposition. Thus, total atmospheric nitrate deposition is roughly three times wet only deposition. Ten subregions of wet only nitrate depositions were delineated by EOF analysis from the entire U.S.A., in which each has a narrow range of annual deposition flux and exhibits unique seasonal variation. The study was based on statistical analysis of chemical concentrations measured for more than 10 years in weekly rainfall samples of the National Atmospheric Deposition Program, NADP, and more than 20 years of river water samples of the U.S. Geological Survey, USGS. NO _{x} emissions appear to regulate the annual average total deposition fluxes while in the subregions rainfall characterizes the seasonal and shorter term variations in wet only depositions. Atmospheric wet and dry deposition ("acid rain") appears to be the principal source of nitrogen in twelve northern Florida watersheds that range from Pensacola to Gainesville (Escambia to Alachua Counties). River fluxes of total dissolved nitrogen average close to the atmospheric deposition fluxes of nitrate and ammonium ions. Factor analysis was applied to the data sets to resolve principal components: (1) in atmospheric data, that distinguish air pollution nitrate and sulfate from sea salt sodium and chloride, and (2) in surface water data, that distinguish ground water calcium, magnesium, and silica from meteoric water nitrate and sulfate. River concentration ratios N/P in the watersheds are high, averaging twice the Redfield mole ratio N/P = 16 for aquatic plant nutrients. The results indicate that excess dissolved nitrogen could be temporarily recycled in the watersheds but not retained, so that it could eventually flow to the coastal zone where N may be a limiting

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

    PubMed

    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. PMID:25706750

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

    PubMed

    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.

  12. Energy deposition of single femtosecond filaments in the atmosphere.

    PubMed

    Rosenthal, E W; Jhajj, N; Larkin, I; Zahedpour, S; Wahlstrand, J K; Milchberg, H M

    2016-08-15

    We present spatially resolved measurements of energy deposition into atmospheric air by femtosecond laser filaments. Single filaments formed with varying laser pulse energy and pulsewidth were examined using longitudinal interferometry, sonographic probing, and direct energy loss measurements. We measure peak and average energy absorption of ∼4  μJ/cm and ∼1  μJ/cm for input pulse powers up to ∼6 times the critical power for self-focusing. PMID:27519120

  13. Atmospheric deposition of polycyclic aromatic hydrocarbons onto Massachusetts Bay

    SciTech Connect

    Golomb, D.; Ryan, D.; Underhill, J.

    1997-12-31

    Wet and dry atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) was measured at biweekly intervals from 15 September 1992 to 16 September 1993 at two sites on Massachusetts Bay, Nahant, near Boston, and Truro, near the tip of Cape Cod. Wet and dry deposition was measured using a conventional wet/dry collector, except that the dry bucket contained a layer of water in order to simulate the uptake of dry deposition onto a water surface. The PAHs were extracted from the aqueous solution/suspension by methylene chloride and analyzed by GC-ECD and GC-MS. Dry and wet depositions of PAHs were significantly greater at Nahant than at Truro, due to the proximity of emission sources in the metropolitan Boston area. Highest deposition of PAHs was observed in the winter season. At Nahant, the total deposition (wet + dry) of PAHs amounted to 970 {mu}g m{sup {minus}2} yr{sup {minus}1}, at Truro 350 {mu}g m{sup {minus}2} yr{sup {minus}1}. Polychlorinated biphenyls (PCBs) were not found above the detection limit of the analytical procedure.

  14. Atmospheric deposition of trace metals onto Massachusetts Bay

    SciTech Connect

    Golomb, D.; Ryan, D.; Eby, N.; Underhill, J.

    1997-12-31

    Wet and dry atmospheric deposition of trace metals was measured at biweekly intervals for one year, from 15 September 1992 to 16 September 1993, at two sites on Massachusetts Bay, Nahant, near Boston and Truro, near the tip of Cape Cod. Wet and dry deposition was measured using a conventional wet/dry collector, except that the dry bucket contained a layer of water in order to simulate the uptake of dry deposition onto a water surface. In addition, at Nahant, a dichotomous particle collector was used to measure metal concentrations on particles. Analytical methods were INAA and ICP-MS. Generally, dry deposition of metals was greater at Nahant than at Truro, and wet deposition was greater or equal at Truro than at Nahant. Averaging results from the two sites, the following deposition rates (wet + dry) were obtained for the Bay in {mu}g m{sup {minus}2} yr{sup {minus}1}: Al 102000, As 132, Cd 405, Co 58, Cr 2700, Cu 3500, Fe 140000, Mn 4420, Ni 7200, Pb 2700, Sb 160, Se 264, Zn 7800.

  15. Oceanic Emissions and Atmospheric Depositions of Volatile Organic Compounds

    NASA Astrophysics Data System (ADS)

    Yang, M.; Blomquist, B.; Beale, R.; Nightingale, P. D.; Liss, P. S.

    2015-12-01

    Atmospheric volatile organic compounds (VOCs) affect the tropospheric oxidative capacity due to their ubiquitous abundance and relatively high reactivity towards the hydroxyal radical. Over the ocean and away from terrestrial emission sources, oxygenated volatile organic compounds (OVOCs) make up a large fraction of VOCs as airmasses age and become more oxidized. In addition to being produced or destroyed in the marine atmosphere, OVOCs can also be emitted from or deposited to the surface ocean. Here we first present direct air-sea flux measurements of three of the most abundant OVOCs - methanol, acetone, and acetaldehyde, by the eddy covariance technique from two cruises in the Atlantic: the Atlantic Meridional Transect in 2012 and the High Wind Gas Exchange Study in 2013. The OVOC mixing ratios were quantified by a high resolution proton-reaction-transfer mass spectrometer with isotopically labeled standards and their air-sea (net) fluxes were derived from the eddy covariance technique. Net methanol flux was consistently from the atmosphere to the surface ocean, while acetone varied from supersaturation (emission) in the subtropics to undersaturation (deposition) in the higher latitudes of the North Atlantic. The net air-sea flux of acetaldehyde is near zero through out the Atlantic despite the apparent supersaturation of this compound in the surface ocean. Knowing the dissolved concentrations and in situ production rates of these compounds in seawater, we then estimate their bulk atmospheric depositions and oceanic emissions. Lastly, we summarize the state of knowledge on the air-sea transport of a number of organic gasses, and postulate the magnitude and environmental impact of total organic carbon transfer between the ocean and the atmosphere.

  16. Spatial variation in atmospheric nitrogen deposition on low canopy vegetation.

    PubMed

    Verhagen, Rene; van Diggelen, Rudy

    2006-12-01

    Current knowledge about the spatial variation of atmospheric nitrogen deposition on a local scale is limited, especially for vegetation with a low canopy. We measured nitrogen deposition on artificial vegetation at variable distances of local nitrogen emitting sources in three nature reserves in the Netherlands, differing in the intensity of agricultural practices in the surroundings. In the nature reserve located in the most intensive agricultural region nitrogen deposition decreased with increasing distance to the local farms, until at a distance of 1500 m from the local nitrogen emitting sources the background level of 15 kg N ha(-1) yr(-1) was reached. No such trend was observed in the other two reserves. Interception was considerably lower than in woodlands and hence affected areas were larger. The results are discussed in relation to the prospects for the conservation or restoration of endangered vegetation types of nutrient-poor soil conditions.

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

    NASA Astrophysics Data System (ADS)

    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.

  18. Direct atmospheric deposition of water-soluble nitrogen to the Gulf of Maine

    NASA Astrophysics Data System (ADS)

    Jordan, C. E.; Talbot, R. W.

    2000-12-01

    Measurements were made at New Castle, New Hampshire, on the shore of the Gulf of Maine from 1994 to 1997 to assess direct atmospheric deposition of water-soluble nitrogen to the surface waters of the gulf. Daily dry deposition was highly variable and ranged from ˜ 1 to 144 μmol N m-2 d-1 (median 16 μmol N m-2 d-1). Wet deposition dominated dry deposition, contributing 80-90% of the total flux annually. Wet deposition was also highly variable and ranged from 3 to 4264 μmol N m-2 d-1 (median 214 μmol N m-2 d-1). Fog water nitrogen deposition could contribute as much as large precipitation nitrogen deposition events, in excess of 500 μmol N m-2d-1. Dissolved organic nitrogen (DON) in precipitation constituted only a small fraction (3%) of the total precipitation nitrogen flux most of the year, except in spring where it comprised 14%, on average, of the total. The total atmospheric direct nitrogen (ADN) deposition numbers reported here do not include the contributions of fog and DON as they were not sampled regularly over the course of this study. The total ADN flux ranged from 1 to 4262 μmol N m-2 d-1 (median 23 μmol N m-2 d-1), depositing 52 mmol N m-2 yr-1 to the surface waters of the Gulf of Maine, 3% of the total N input to those waters annually. However, this deposition was highly episodic with events over 500 μmol N m-2 d-1 occurring in 8% of the days sampled but contributing 56% of the total measured flux and events in excess of 1000 μmol N m-2 d-1 occurring in 2% of the samples and contributing 22% of the total measured flux. It is these large events that may influence biological productivity of the Gulf of Maine. The annual wet deposition of inorganic N measured at New Castle exceeded that reported by two National Atmospheric Deposition Program (NADP) sites by 42% on average of that reported from Cape Cod, Massachusetts, and by 69% ofthat at Mt. Dessert Island, Maine. Estimates of the episodic atmospheric nitrogen flux to the surface waters of the

  19. Atmospheric sulfur deposition and streamwater quality in Finland

    NASA Astrophysics Data System (ADS)

    Lahermo, P. W.; Tarvainen, T.; Tuovinen, J.-P.

    1994-10-01

    The correlation between sulfate concentrations in Finnish headwater streams and atmospheric sulfate deposition has been studied by using data from the streamwater chemistry in August September 1990 and computed S deposition from the anthropogenic emissions. The sulfate concentrations and acidity in water are interpolated and smoothed into a deposition model grid. These data are compared with geological and pedogeochemical (glacial till) background information. The areas where the streamwater SO4 concentrations are mainly controlled by either anthropogenic S deposition or sulfur in till is estimated by applying the fuzzy Gustafsson-Kessel algorithm, which provides a soft clustering suitable for overlapping control factors. Residual areas can be well explained by the SO4-rich Littorina clay deposits. The higher overall background SO4 concentrations in streams in south Finland compared with central and northern Finland are an indisputable consequence of the heavier S deposition load in the south. However, anthropogenic sulfur deposition has a clear correlation with the sulfates in streamwaters only in northeastern Lapland impacted by the large industrial emissions in the Kola Peninsula. The secondary sulfide and sulfate minerals of marine Littorina sediments are dominating sources in the broad coastal belts, as are the primary sulfide minerals locally in the Pori-Vammala area, at the eastern end of the main sulfide ore belt between Lake Ladoga and the Gulf of Bothnia, in the Outokumpu area, and in the Peräpohja and central Lapland schist belts. Consequently, in addition to the anthropogenic deposition, there are natural sources of sulfur which cause acidity of streamwaters.

  20. Atmospheric Deposition and Fate of Mercury in High-altitude Watersheds of the Rocky Mountains.

    NASA Astrophysics Data System (ADS)

    Campbell, D. H.; Mast, M. A.; Ingersoll, G. P.; Manthorne, D. J.; Krabbenhoft, D. P.; Taylor, H. E.; Aiken, G. R.; Schuster, P. F.; Reddy, M. M.

    2003-12-01

    Despite the potential for cold high-altitude ecosystems to act as sinks in the global mercury cycle, atmospheric deposition and fate of mercury have not been measured extensively at mountain sites in the Western United States. At Buffalo Pass in northwestern Colorado (the highest site in the national Mercury Deposition Network at 3234 m elevation), mercury in wet deposition was 9 μ gm-2 in 2000, comparable to many sites in the upper Midwestern United States where fish consumption advisories are widespread because of elevated levels of mercury from atmospheric deposition. Similar levels of mercury deposition were measured about 90 km east of Buffalo Pass at Loch Vale in Rocky Mountain National Park (RMNP) during 2002. Concentrations of total mercury in headwater streams in RMNP averaged 2-4 ngL-1 during spring and summer of 2001-2002. Higher concentrations were observed during snowmelt and rainfall events. Dissolved mercury was generally greater than particulate mercury in these clear mountain streams. Mercury and dissolved organic carbon peaked as soils were flushed during early snowmelt and rainy summer periods. Overall, mercury deposition was greater than mercury export, indicating accumulation in alpine/subalpine ecosystems; however, the mercury exported in streamflow may contribute substantially to mercury loading in downstream lakes and reservoirs where fish consumption advisories have increased. Methyl mercury concentrations measured in the streams in 2002 were generally near or less than detection limits, however, extreme drought conditions limited hydrologic flushing of soils and wetlands that may be sources of methyl mercury. In 2003, surface and ground water from various alpine and subalpine landscapes were sampled to determine sources and transport of total and methyl mercury. The elevated levels of mercury in atmospheric deposition indicate a need for better understanding of mercury cycling and transport in high-altitude ecosystems of Western North

  1. Atmospheric deposition and hydrogeologic flow of nitrogen in northern Florida watersheds

    NASA Astrophysics Data System (ADS)

    Winchester, John W.; Escalona, Leyda; Fu, Ji-Meng; Furbish, David J.

    1995-06-01

    Atmospheric wet and dry deposition ("acid rain") appears to be the principal source of nitrogen in twelve northern Florida watersheds that range from Pensacola to Gainesville (Escambia to Alachua Counties). The study was based on statistical analysis of chemical concentrations measured for more than ten years in weekly rainfall samples of the National Atmospheric Deposition Program, NADP, and more than twenty years of river water samples of the US Geological Survey, USGS. River fluxes of total dissolved nitrogen average close to the atmospheric deposition fluxes of nitrate and ammonium ions. Factor analysis was applied to the datasets to resolve principal components: (1) in atmospheric data, that distinguish air pollution nitrate and sulfate from sea salt sodium and chloride, and (2) in surface water data, that distinguish ground water Ca, Mg, and silica from meteoric water nitrate and sulfate. Relationships within the sets of measured concentration data suggest that, following atmospheric deposition, inorganic nitrogen undergoes biogeochemical transformation within the watersheds, which results in inorganic nitrogen being transformed to organic forms. River concentration ratios N/P in the watersheds are high, averaging twice the Redfield mole ratio N/P = 16 for aquatic plant nutrients. The results indicate that excess dissolved nitrogen could be temporarily recycled in the watersheds but not retained, so that it could eventually flow to the coastal zone where N may be a limiting nutrient for marine plants. Chemical interactions of meteoric water within the watersheds depend on geologic, hydrologic, and biogeochemical processes and are certainly complex. However, in one watershed that is geologically the simplest, separate statistical analyses of river water composition during high and low flow conditions show nitrate and sulfate to be correlated during high flow, but not during low flow, providing further evidence for an atmospheric nitrogen source and watershed

  2. Modeling Atmospheric Energy Deposition (by energetic ions): New Results

    NASA Astrophysics Data System (ADS)

    Parkinson, C.; Brain, D. A.; Lillis, R. J.; Liemohn, M. W.; Bougher, S. W.

    2012-12-01

    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. Such modeling has been previously done for Earth, Mars and Jupiter using a guiding center precipitation model with extensive collisional physics. 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 that can perform calculations for cases where there is only a weak or nonexistent magnetic field that includes detailed physical interaction with the atmosphere (i.e. collisional physics). We show initial efforts to apply a full Lorentz motion particle transport model to study the effects of particle precipitation in the upper atmospheres of Venus, Mars, and Titan. A systematic study of the ionization, excitation, and energy

  3. Modeling Planetary Atmospheric Energy Deposition By Energetic Ions

    NASA Astrophysics Data System (ADS)

    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

  4. Acid rain and dry deposition of atmospheric pollutants: ORNL studies the effects

    SciTech Connect

    Shriner, D.

    1984-01-01

    Acidic precipitation and atmospheric deposition may be involved in the decline of some forests and in the elevation of aluminum levels in streams. The research programs at Oak Ridge National Laboratory which are focussed on acid rain are described. Some of the areas currently under scrutiny are: soil buffering capacity, the quantitative relationships between wet and dry deposition, the effects of acid rain on forest growth, forest canopy interactions with acid precipitation, the effects of acid rain on aquatic ecosystems, and innovations in pollution control technology.

  5. Mechanisms controlling soil carbon sequestration under atmospheric nitrogen deposition

    SciTech Connect

    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.

  6. Atmospheric Deposition of Soluble Organic Nitrogen due to Biomass Burning

    NASA Astrophysics Data System (ADS)

    Ito, A.; Lin, G.; Penner, J. E.

    2014-12-01

    Atmospheric deposition of reactive nitrogen (N) species from large fires may contribute to enrichment of nutrients in aquatic ecosystems. Here we use an atmospheric chemistry transport model to investigate the supply of soluble organic nitrogen (ON) from open biomass burning to the ocean. The model results show that the annual deposition rate of soluble ON to the oceans is increased globally by 13% with the increase being particularly notable over the coastal water downwind from the source regions. The estimated deposition of soluble ON due to haze events from the secondary formation is more than half of that from the primary sources. We examine the secondary formation of particulate C-N compounds (e.g., imidazole) from the reactions of glyoxal and methylglyoxal with atmospheric ammonium in wet aerosols and upon cloud evaporation. These ON sources result in a significant contribution to the open ocean, suggesting that atmospheric processing in aqueous phase may have a large effect. We compare the soluble ON concentration in aerosols with and without open biomass burning as a case study in Singapore. The model results demonstrate that the soluble ON concentration in aerosols is episodically enriched during the fire events, compared to the without smoke simulations. However, the model results show that the daily soluble ON concentration can be also enhanced in the without smoke simulations during the same period, compared to the monthly averages. This indicates that care should be taken when using in-situ observations to constrain the soluble ON source strength from biomass burning. More accurate quantification of the soluble ON burdens with no smoke sources is therefore needed to assess the effect of biomass burning on bioavailable ON input to the oceans.

  7. Heavy-Particle Deposition in the Atmospheric Boundary Layer.

    NASA Astrophysics Data System (ADS)

    Liao, Yingcheng

    A set of experiments of heavy-particle deposition on the ground in a wind-tunnel simulated atmospheric boundary layer has been conducted. Different particle fall velocities and different wind speeds were used. In order to analyze inertial, continuity, and crossing-trajectories effects of heavy particles, a new random-walk model has been developed in which vertical velocity variance is a function of height. For calibration of the numerical model, a set of tracer-gas concentration measurements was also carried out. The analysis of experimental results reveals that, in the atmospheric surface layer, for most of the practical situations, the crossing-trajectories and the inertia of heavy particles have a very limited effect on heavy-particle dispersion and deposition. However, the continuity effect greatly affects the lateral dispersion and deposition of heavy particles. The continuity effect is strongly height dependent. Influences of different factors on heavy-particle deposition are discussed. This includes the fall-velocity distribution of heavy particles, the integral-time scales of turbulent flow, longitudinal turbulent velocity components, release height, etc. Comparisons between the theoretical prediction and the calculated results from both the model used in this study and the model of Legg and Raupach (1982) support the author's approach in which vertical velocity variance is taken to be height dependent. For practical purposes, the new random-walk model has greatly improved the accuracy of predicting longitudinal deposition of heavy particles compared to that of the traditional Gaussian model. Experiments with more release heights and larger differences of particle fall velocity are suggested in order to further confirm the findings of this dissertation.

  8. Heavy-particle deposition in the atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Liao, Yingcheng

    A set of experiments of heavy-particle deposition on the ground in a wind-tunnel simulated atmospheric boundary layer was conducted. Different particle fall velocities and different wind speeds were used. In order to analyze inertial, continuity, and crossing-trajectories effects of heavy particles, a new random-walk model was developed in which vertical velocity variance is a function of height. For calibration of the numerical model, a set of tracer-gas concentration measurements was also carried out. The analysis of experimental results reveals that, in the atmospheric surface layer, for most of the practical situations, the crossing-trajectories and the inertia of heavy particles have a very limited effect on heavy-particle dispersion and deposition. However, the continuity effect greatly affects the lateral dispersion and deposition of heavy particles. The continuity effect is strongly height dependent. Influences of different factors on heavy-particle deposition are discussed. This includes the fall-velocity distribution of heavy particles, the integral-time scales of turbulent flow, longitudinal turbulent velocity components, release height, etc. Comparisons between the theoretical prediction and the calculated results from both the model used in this study and the model of Legg and Raupach (1982) support the author's approach in which vertical velocity variance is taken to be height dependent. For practical purposes, the new random-walk model has greatly improved the accuracy of predicting longitudinal deposition of heavy particles compared to that of the traditional Gaussian model. Experiments with more release heights and larger differences of particle fall velocity are suggested in order to further confirm the findings.

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

    PubMed

    Geiser, Linda H; Jovan, Sarah E; Glavich, Doug A; Porter, Matthew K

    2010-07-01

    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(-1)y(-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.

  10. Ammonia in the atmosphere: a review on emission sources, atmospheric chemistry and deposition on terrestrial bodies.

    PubMed

    Behera, Sailesh N; Sharma, Mukesh; Aneja, Viney P; Balasubramanian, Rajasekhar

    2013-11-01

    Gaseous ammonia (NH3) is the most abundant alkaline gas in the atmosphere. In addition, it is a major component of total reactive nitrogen. The largest source of NH3 emissions is agriculture, including animal husbandry and NH3-based fertilizer applications. Other sources of NH3 include industrial processes, vehicular emissions and volatilization from soils and oceans. Recent studies have indicated that NH3 emissions have been increasing over the last few decades on a global scale. This is a concern because NH3 plays a significant role in the formation of atmospheric particulate matter, visibility degradation and atmospheric deposition of nitrogen to sensitive ecosystems. Thus, the increase in NH3 emissions negatively influences environmental and public health as well as climate change. For these reasons, it is important to have a clear understanding of the sources, deposition and atmospheric behaviour of NH3. Over the last two decades, a number of research papers have addressed pertinent issues related to NH3 emissions into the atmosphere at global, regional and local scales. This review article integrates the knowledge available on atmospheric NH3 from the literature in a systematic manner, describes the environmental implications of unabated NH3 emissions and provides a scientific basis for developing effective control strategies for NH3. PMID:23982822

  11. Ammonia in the atmosphere: a review on emission sources, atmospheric chemistry and deposition on terrestrial bodies.

    PubMed

    Behera, Sailesh N; Sharma, Mukesh; Aneja, Viney P; Balasubramanian, Rajasekhar

    2013-11-01

    Gaseous ammonia (NH3) is the most abundant alkaline gas in the atmosphere. In addition, it is a major component of total reactive nitrogen. The largest source of NH3 emissions is agriculture, including animal husbandry and NH3-based fertilizer applications. Other sources of NH3 include industrial processes, vehicular emissions and volatilization from soils and oceans. Recent studies have indicated that NH3 emissions have been increasing over the last few decades on a global scale. This is a concern because NH3 plays a significant role in the formation of atmospheric particulate matter, visibility degradation and atmospheric deposition of nitrogen to sensitive ecosystems. Thus, the increase in NH3 emissions negatively influences environmental and public health as well as climate change. For these reasons, it is important to have a clear understanding of the sources, deposition and atmospheric behaviour of NH3. Over the last two decades, a number of research papers have addressed pertinent issues related to NH3 emissions into the atmosphere at global, regional and local scales. This review article integrates the knowledge available on atmospheric NH3 from the literature in a systematic manner, describes the environmental implications of unabated NH3 emissions and provides a scientific basis for developing effective control strategies for NH3.

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

    USGS Publications Warehouse

    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

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

    NASA Astrophysics Data System (ADS)

    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.

  14. Microbial release of sulphur ions from atmospheric pollution deposits

    SciTech Connect

    Killhan, K.; Wainwright, M.

    1981-12-01

    The surfaces of leaves of Acer pseudoplatanus growing in areas exposed to heavy atmospheric pollution are covered with atmospheric pollution deposits (APD). Using scanning electron microscopy, micro-organisms were seen to be growing in intimate association with these deposits. The deposits contained sufficient carbon and nitrogen to support growth of the fungus Fusarium solani in culture and in autoclaved and non-sterilized soils; and sufficient reduced sulphur for the in vitro growth of Thiobacillus thioparus. When T. thioparus and F. solani were grown in medium supplemented with APD as sole carbon and nitrogen sources, increases in the concentrations of soluble S/sub 2/O/sup 2 -//sub 3/; S/sub 4/O/sup 2 -//sub 6/ and SO/sup 2 -//sub 4/ resulted. Similar increases also occurred when APD was added to complete fungal growth medium. Increases in LiCl/sub 2/-extractable sulphur-ions also occurred in fresh soil amended with APD, and in autoclaved soils containing APD, and inoculated with spores of F. solani. Arylsulphatase activity increased in fresh soils and in soils autoclaved and inoculated with F. solani when APD was added; suggesting sulphur mineralization, as well as sulphur oxidation, in the release of sulphur ions from APD. We concluded that APD can support microbial growth in vitro and in soils when provided as sole carbon and sulphur source; and that micro-organisms can release sulphur ions from this complex substrate. Microbial release of sulphur ions from APD can account in part for the increased concentrations of sulphur ions in heavy atmospheric-polluted soils.

  15. Microbial release of sulphur ions from atmospheric pollution deposits

    SciTech Connect

    Killham, K.; Wainwright, M.

    1981-12-01

    The surface of leaves of Acer pseudoplatanus growing in areas exposed to heavy atmospheric pollution are covered with atmospheric pollution deposits (APD). Using scanning electric microscopy, micro-organisms were seen to be growing in intimate association with these deposits. The deposits contained sufficient carbon and nitrogen to support growth of the fungus Fusarium solani in culture and in autoclaved and non-sterilized soils; and sufficient reduced sulphur for in vitro growth of Thiobacillus thioparus. When T. thioparus and F. solani were grown in medium supplemented with APD as sole carbon and nitrogen sources, increases in the concentrations of soluble S/sub 2/O/sub 3//sup 2/ btw/sup -/ and; S/sub 4/O/sub 6//sup 2 -/ and SO/sub 4//sup 2 -/ resulted. Similar increases also occurred when APD was added to complete fungal growth medium. Increases in LiCl/sub 2/-extractable sulphur-ions also occurred is fresh soil amended with APD, and in autoclaved soils containing APD, and inoculated with spores of F. solani. Arylsulphatase activity increased in fresh soils and in soils autoclaved and inoculated with F. solani when APD was added; suggesting sulphur mineralization, as well as sulphur oxidation, in the release of sulphur ions from APD. We conclude that APD can support microbial growth in vitro and in soils when provided as sole carbon and sulphur source; and that micro-organisms can release sulphur ions from this complex substrate. Microbial release of sulphur ions from APD can account in part for the increased concentrations of sulphur ions in heavy atmospheric-polluted soils.

  16. The effects of uncertainty on the analysis of atmospheric deposition

    SciTech Connect

    Bloyd, C.N. ); Small, M.J.; Henrion, M.; Rubin, E.S. )

    1988-01-01

    Research efforts on the problem of acid ran are directed at improving current scientific understanding in critical areas, including sources of precursor emissions, the transport and transformation of pollutants in the atmosphere, the deposition of acidic species, and the chemical and biological effects of acid deposition on aquatic systems, materials, forests, crops and human health. The general goal of these research efforts is to characterize the current situation and to develop analytical models which can be used to predict the response of various systems to changes in critical parameters. This paper describes a framework which enables one to characterize uncertainty at each major stage of the modeling process. Following a general presentation of the modeling framework, a description is given of the methods chosen to characterize uncertainty for each major step. Analysis is then performed to illustrate the effects of uncertainty on future lake acidification in the Adirondacks Park area of upstate New York.

  17. [Nutrients in atmospheric wet deposition in the East China Sea].

    PubMed

    Zhu, Yu-Mei; Liu, Su-Mei

    2011-09-01

    92 rainwater samples were collected at Shengsi Archipelago from January 2008 to December 2009. The pH and the concentrations of nutrients (NH4(+), NO3(-) + NO2(-), PO4(3-), SiO3(2-)) were analyzed using spectrophotometry to understand the impacts of the atmospheric wet deposition on the ecosystem of the East China Sea. The results showed that the pH of 85% samples were less than 5.0, and had significant effect on the environment. There were significant differences among monthly average concentrations of nutrients and rainfall and seasonal average wet deposition of nutrients in investigation periods. The annual average wet deposition flux was 52.05 mmol x (m2 x a) (-1) for DIN, 0.08 mmol x (m2 x a) (-1) for PO4(3-), 2.05 mmol x (m2 x a) (-1) for SiO3(2-). The average molar ratios of NO3(-)/NH4(+) is 0.73, N: P ratio is 684: 1, indicating that nutrients composition in rainwater was different from seawater of the East China Sea Shelf (10-150). The wet deposition may change the nutrients structure, pH and lead to change the phytoplankton production in the surface seawater of the East China Sea, even lead to the red tide. PMID:22165245

  18. [Nutrients in atmospheric wet deposition in the East China Sea].

    PubMed

    Zhu, Yu-Mei; Liu, Su-Mei

    2011-09-01

    92 rainwater samples were collected at Shengsi Archipelago from January 2008 to December 2009. The pH and the concentrations of nutrients (NH4(+), NO3(-) + NO2(-), PO4(3-), SiO3(2-)) were analyzed using spectrophotometry to understand the impacts of the atmospheric wet deposition on the ecosystem of the East China Sea. The results showed that the pH of 85% samples were less than 5.0, and had significant effect on the environment. There were significant differences among monthly average concentrations of nutrients and rainfall and seasonal average wet deposition of nutrients in investigation periods. The annual average wet deposition flux was 52.05 mmol x (m2 x a) (-1) for DIN, 0.08 mmol x (m2 x a) (-1) for PO4(3-), 2.05 mmol x (m2 x a) (-1) for SiO3(2-). The average molar ratios of NO3(-)/NH4(+) is 0.73, N: P ratio is 684: 1, indicating that nutrients composition in rainwater was different from seawater of the East China Sea Shelf (10-150). The wet deposition may change the nutrients structure, pH and lead to change the phytoplankton production in the surface seawater of the East China Sea, even lead to the red tide.

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

    USGS Publications Warehouse

    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.

  20. Modeling atmospheric mercury deposition in the vicinity of power plants.

    PubMed

    Seigneur, Christian; Lohman, Kristen; Vijayaraghavan, Krish; Jansen, John; Levin, Leonard

    2006-06-01

    Two mathematical models of the atmospheric fate and transport of mercury (Hg), an Eulerian grid-based model and a Gaussian plume model, are used to calculate the atmospheric deposition of Hg in the vicinity (i.e., within 50 km) of five coal-fired power plants. The former is applied using two different horizontal resolutions: coarse (84 km) and fine (16.7 km). More than 96% of the power plant Hg emissions are calculated with the plume model to be transported beyond 50 km from the plants. The grid-based model predicts a lower fraction to be transported beyond 50 km: >91% with a coarse resolution and >95% with a fine resolution. The contribution of the power plant emissions to total Hg deposition within a radius of 50 km from the plants is calculated to be <8% with the plume model, <14% with the Eulerian model with a coarse resolution, and <10% with the Eulerian model with a fine resolution. The Eulerian grid-based model predicts greater local impacts than the plume model because of artificially enhanced vertical dispersion; the former predicts about twice as much Hg deposition as the latter when the area considered is commensurate with the resolution of the grid-based model. If one compares the local impacts for an area that is significantly less than the grid-based model resolution, then the grid-based model may predict lower local deposition than the plume model, because two compensating errors affect the results obtained with the grid-based model: initial dilution of the power plant emissions within one or more grid cells and enhanced vertical mixing to the ground.

  1. Stable isotopes in alpine precipitation as tracers of atmospheric deposition

    NASA Astrophysics Data System (ADS)

    Wasiuta, V. L.; Lafreniere, M. J.; Kyser, T. K.; Norman, A. L.; Mayer, B.; Wieser, M.

    2010-12-01

    Alpine ecosystems, which are generally nutrient poor and exist under extreme climatic conditions, are particularly sensitive to environmental and climatic stressors. Studies in the USA Rocky Mountains and European Alps have shown that alpine terrestrial and aquatic ecosystems are particularly sensitive to enhanced deposition of reactive nitrogen and can show ecologically destructive responses at relatively low levels of nitrogen deposition. However, there is no base line for atmospheric deposition of natural and anthropogenic contaminants in the Canadian alpine. Preliminary results of isotopic and chemical analyses of precipitation from an elevational transect on a glaciated alpine site in the Canadian Rockies are presented. Precipitation accumulating from early autumn through to spring (2008/2009 and 2009/2010) was sampled by means of seasonal snow cover on alpine glaciers. Summer precipitation was sampled through July and August 2010 using bulk collectors installed at the sites of winter sampling. The isotope ratios of dissolved sulphate (δ34S, δ18O), nitrogen (δ15N, δ18O), as well as precipitation (δ2H, δ18O) are utilized in addition to major ion concentrations and trace metal concentrations. Results from 2008/2009 snowpack samples indicate a strong seasonal trend in sulphate (SO42-) and nitrogen (NO3-) deposition which is consistent across the altitudinal transect. Snow horizons representing early autumn and spring precipitation show higher SO42- and NO3- concentrations in contrast to lower concentrations in winter horizons. The aforementioned suite of isotopic and chemical analyses are used to investigate the variability in dominant geographic source regions for atmospheric SO42- and NO3- (local, regional, or long range transported contaminants), as well as to identify contributions from the major biogeochemical source types (e.g. hydrocarbon combustion, lithogenic dust, agricultural emissions).

  2. Energy deposition rates by charged particles. [in upper atmosphere

    NASA Technical Reports Server (NTRS)

    Torkar, K. M.; Urban, A.; Bjordal, J.; Lundblad, J. A.; Soraas, F.; Smith, L. G.; Dumbs, A.; Grandal, B.; Ulwick, J. C.; Vancour, R. P.

    1985-01-01

    A summary of measurements of the precipitation of electrons and positive ions (in the keV-MeV range) detected aboard eight rockets launched within the Energy Budget Campaign from Northern Scandinavia is given, together with corresponding satellite data. In some cases strong temporal variations of the downgoing integral fluxes were observed. The fluxes provide the background for the calculated ion production rates and altitude profiles of the energy deposition into the atmosphere at different levels of geomagnetic disturbance and cosmic noise absorption. The derived ion production rates by eneretic particles are compared to other night-time ionisation sources.

  3. Electron deposition in water vapor, with atmospheric applications.

    NASA Technical Reports Server (NTRS)

    Olivero, J. J.; Stagat, R. W.; Green, A. E. S.

    1972-01-01

    Examination of the consequences of electron impact on water vapor in terms of the microscopic details of excitation, dissociation, ionization, and combinations of these processes. Basic electron-impact cross-section data are assembled in many forms and are incorporated into semianalytic functions suitable for analysis with digital computers. Energy deposition in water vapor is discussed, and the energy loss function is presented, along with the 'electron volts per ion pair' and the efficiencies of energy loss in various processes. Several applications of electron and water-vapor interactions in the atmospheric sciences are considered, in particular, H2O comets, aurora and airglow, and lightning.

  4. Atmospheric Plasma Deposition of Diamond-like Carbon Coatings

    SciTech Connect

    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.

  5. Atmospheric mercury speciation in Yellowstone National Park

    USGS Publications Warehouse

    Hall, B.D.; Olson, M.L.; Rutter, A.P.; Frontiera, R.R.; Krabbenhoft, D.P.; Gross, D.S.; Yuen, M.; Rudolph, T.M.; Schauer, J.J.

    2006-01-01

    Atmospheric concentrations of elemental mercury (Hg0), reactive gaseous Hg (RGM), and particulate Hg (pHg) concentrations were measured in Yellowstone National Park (YNP), U.S.A. using high resolution, real time atmospheric mercury analyzers (Tekran 2537A, 1130, and 1135). A survey of Hg0 concentrations at various locations within YNP showed that concentrations generally reflect global background concentrations of 1.5-2.0 ng m- 3, but a few specific locations associated with concentrated geothermal activity showed distinctly elevated Hg0 concentrations (about 9.0 ng m- 3). At the site of intensive study located centrally in YNP (Canyon Village), Hg0 concentrations did not exceed 2.5 ng m- 3; concentrations of RGM were generally below detection limits of 0.88 pg m- 3 and never exceeded 5 pg m- 3. Concentrations of pHg ranged from below detection limits to close to 30 pg m-3. RGM and pHg concentrations were not correlated with any criteria gases (SO2, NOx, O3); however pHg was weakly correlated with the concentration of atmospheric particles. We investigated three likely sources of Hg at the intensive monitoring site: numerous geothermal features scattered throughout YNP, re-suspended soils, and wildfires near or in YNP. We examined relationships between the chemical properties of aerosols (as measured using real time, single particle mass spectrometry; aerosol time-of-flight mass spectrometer; ATOFMS) and concentrations of atmospheric pHg. Based on the presence of particles with distinct chemical signatures of the wildfires, and the absence of signatures associated with the other sources, we concluded that wildfires in the park were the main source of aerosols and associated pHg to our sampling site. ?? 2005 Elsevier B.V. All rights reserved.

  6. Atmospheric mercury speciation in Yellowstone National Park.

    PubMed

    Hall, B D; Olson, M L; Rutter, A P; Frontiera, R R; Krabbenhoft, D P; Gross, D S; Yuen, M; Rudolph, T M; Schauer, J J

    2006-08-15

    Atmospheric concentrations of elemental mercury (Hg(0)), reactive gaseous Hg (RGM), and particulate Hg (pHg) concentrations were measured in Yellowstone National Park (YNP), U.S.A. using high resolution, real time atmospheric mercury analyzers (Tekran 2537A, 1130, and 1135). A survey of Hg(0) concentrations at various locations within YNP showed that concentrations generally reflect global background concentrations of 1.5-2.0 ng m(-3), but a few specific locations associated with concentrated geothermal activity showed distinctly elevated Hg(0) concentrations (about 9.0 ng m(-3)). At the site of intensive study located centrally in YNP (Canyon Village), Hg(0) concentrations did not exceed 2.5 ng m(-3); concentrations of RGM were generally below detection limits of 0.88 pg m(-3) and never exceeded 5 pg m(-3). Concentrations of pHg ranged from below detection limits to close to 30 pg m(-3). RGM and pHg concentrations were not correlated with any criteria gases (SO(2), NO(x), O(3)); however pHg was weakly correlated with the concentration of atmospheric particles. We investigated three likely sources of Hg at the intensive monitoring site: numerous geothermal features scattered throughout YNP, re-suspended soils, and wildfires near or in YNP. We examined relationships between the chemical properties of aerosols (as measured using real time, single particle mass spectrometry; aerosol time-of-flight mass spectrometer; ATOFMS) and concentrations of atmospheric pHg. Based on the presence of particles with distinct chemical signatures of the wildfires, and the absence of signatures associated with the other sources, we concluded that wildfires in the park were the main source of aerosols and associated pHg to our sampling site.

  7. Estimates of the atmospheric deposition of sulfur and nitrogen species: Clean Air Status and Trends Network 1990-2000.

    PubMed

    Baumgardner, Ralph E; Lavery, Thomas F; Rogers, Christopher M; Isil, Selma S

    2002-06-15

    The Clean Air Status and Trends Network (CASTNet) was established by the U.S. EPA in response to the requirements of the 1990 Clean Air Act Amendments. To satisfy these requirements CASTNet was designed to assess and report on geographic patterns and long-term, temporal trends in ambient air pollution and acid deposition in order to gauge the effectiveness of current and future mandated emission reductions. This paper presents an analysis of the spatial patterns of deposition of sulfur and nitrogen pollutants for the period 1990-2000. Estimates of deposition are provided for two 4-yr periods: 1990-1993 and 1997-2000. These two periods were selected to contrast deposition before and after the large decrease in SO2 emissions that occurred in 1995. Estimates of dry deposition were obtained from measurements at CASTNet sites combined with deposition velocities that were modeled using the multilayer model, a 20-layer model that simulates the various atmospheric processes that contribute to dry deposition. Estimates of wet deposition were obtained from measurements at sites operated bythe National Atmospheric Deposition Program. The estimates of dry and wet deposition were combined to calculate total deposition of atmospheric sulfur (dry SO2, dry and wet SO4(2-)) and nitrogen (dry HNO3, dry and wet NO3-, dry and wet NH4+). An analysis of the deposition estimates showed a significant decline in sulfur deposition and no change in nitrogen deposition. The highest rates of sulfur deposition were observed in the Ohio River Valley and downwind states. This region also observed the largest decline in sulfur deposition. The highest rates of nitrogen deposition were observed in the Midwest from Illinois to southern New York State. Sulfur and nitrogen deposition fluxes were significantly higher in the eastern United States as compared to the western sites. Dry deposition contributed approximately 38% of total sulfur deposition and 30% of total nitrogen deposition in the eastern

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

    NASA Astrophysics Data System (ADS)

    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

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

    USGS Publications Warehouse

    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.

  10. Multi-elements atmospheric deposition study in Albania.

    PubMed

    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.

  11. Status and trends in atmospheric deposition and emissions near Atlanta, Georgia, 1986-99

    USGS Publications Warehouse

    Peters, N.E.; Meyers, T.P.; Aulenbach, Brent T.

    2002-01-01

    Wet and dry atmospheric deposition were investigated from weekly data, 1986-99 (1986-97 for dry deposition) at the Panola Mountain Research Watershed (PMRW), a forested research site 25 km, southeast of Atlanta, Georgia. Furthermore, the wet deposition was compared to that at three adjacent National Atmospheric Deposition Program's National Trends Network (NTN) sites (GA41, 50 km south of PMRW; AL99, 175 km northwest; NC25, 175 km north-northeast) and dry deposition was compared to that at adjacent Clean Air Status and Trends Network (CASTNET) sites, co-located at the NTN sites. The pH of precipitation is acidic and the dominant acid anion is SO4; the pH (derived from the volume-weighted mean H concentration) averages 4.44 for 1986-99, and varies seasonally with average lowest values in summer (4.19) and highest in winter (4.63). From 1986-99, the annual wet deposition of sulfur (S) and nitrogen (N) averaged 400 and 300 eq ha-1 (6.4 and 4.2 kg ha-1), respectively. Inferential model estimates of annual dry S and N deposition from 1986-97 averaged 130 and 150 eq ha-1 (2.1 and 2.1 kg ha-1), respectively. From 1993-99, net S deposition (dry deposition plus canopy interactions) for coniferous and deciduous throughfall (throughfall minus wet-only deposition) averaged 400 and 150 eq ha-1 (6.4 and 2.1 kg ha-1), respectively. The annual wet deposition of S and N species at PMRW was comparable to that at NTN sites, with the exception of higher N species deposition at AL99 and relatively lower H, SO4 and NO3 deposition at GA41. Dry S deposition at PMRW differed markedly from the CASTNET sites despite similarity in S concentrations for all but NC25; the differences are attributed to differences in model parameters associated with the landscape and vegetation characteristics at the sites. At PMRW, atmospheric deposition trends were not detected for the entire sampling period, but were detected for shorter periods (4-5yr). Annual S and N deposition increased from 1986 to 1991

  12. Simulating soil atmosphere above a leaky CCS deposit

    NASA Astrophysics Data System (ADS)

    Schack-Kirchner, Helmer; Maier, Martin

    2015-04-01

    The escape of CO2 at the surface above a leaky geological deposit of carbon dioxide can be a fumarole-like point source or a subsurface plume distributing the gas over a larger area. In the latter case the lost CO2 from the deposit is added to the soil respiration as a quasi one-dimensional non-equimolar gas flux. Whether such an additional flux leads to inhibitory high levels of soil CO2 combined with a rather complete advective displacement of O2 or simply changes the diffusion characteristics in a more or less normal soil atmosphere depends for a given gas diffusivity and permeability on the ratio between the equimolar (respiratory) and the non-equimolar (leak based) flux of CO2. We tested the effecs by parametrization of a conceptual soil model consisting of capillaries filled either with soil air or water joining the soil air and the above-ground atmosphere. Soil atmosphere was simulated by combining a numerical solution of the Dusty-Gas model and a simple gas diffusion model in the water filled capillaries in an iterative process until Argon as noble gas is stagnant. The results show that in soils with high gas permeability even non-equimolar CO2 fluxes more than twice the soil respiration can be transferred to the surface without spectacular changes in soil-air pressure or O2 displacement. However, even low extra CO2 fluxes change significantly the gradient ratio of O2 and CO2 and stress soil aeration which is for many forest ecosystems a limiting factor of root growth.

  13. Sources and Ecosystem Effects of Atmospheric Mercury Deposition in Southwest Colorado, USA

    NASA Astrophysics Data System (ADS)

    Nydick, K. R.; Wright, W.

    2008-12-01

    Some of the highest concentrations of wet atmospheric deposition of mercury for the U.S. are recorded in Mesa Verde National Park in the southwest corner of Colorado, and several nearby reservoirs have fish consumption advisories for mercury. We asked whether or not similarly high concentrations of mercury are deposited at two sites near a high-elevation, class one Wilderness Area, which is farther from potential local sources of mercury emissions than the National Park but receives more annual precipitation. Back trajectory analyses were used to investigate sources of the mercury in the deposition samples. We further asked how much mercury is incorporated into the zooplankton of 28 lakes and reservoirs in this region and investigated biological and physical sources of variability. Sediment cores from four of the high-elevation lakes were analyzed to understand changes in mercury flux over time. Wet deposition samples collected from April to October 2007 had concentrations of 3-70 ng Hg/L, which were slightly lower than samples from the National Park. Back trajectory analyses suggest that samples with high mercury concentration often are associated with source areas to the south and southwest that have coal-fired power plants. Mercury in zooplankton varied greatly among size fractions and lakes, ranging from undetectable to 89 ng MeHg/g dry for the 80-300 um size class and 5-185 ng MeHg/g dry. Mercury flux measured by sediment cores increased from preindustrial levels beginning ~1870 and either peaked from 1970-1990 before declining to mid-levels after 1990 or increased rapidly starting at about 1960 but did not demonstrate much of a decline after 1990. These data show that atmospheric mercury is being deposited at high concentrations at high-elevation sites downwind of a coal-fired energy production area, but that the effect on aquatic food webs is variable. Sources of variability will be discussed.

  14. [Atmospheric deposition of PAHs in Dashiwei Karst Tiankeng Group in Leye, Guangxi].

    PubMed

    Kong, Xiang-Sheng; Qi, Shi-Hua; Huang, Bao-Jian; Zhang, Yuan; Li, Jie

    2012-03-01

    In order to understand atmospheric deposition of polycyclic aromatic hydrocarbons impact on ecological environment of Dashiwei Karst Tiankeng Group in Leye County, Guangxi (National Geological Park), the dry and wet deposition samples around Dashiwei Tiankeng were collected by season for a year, and were analyzed utilizing GC-MS for 16 EPA PAHs. The results showed that PAH depositional fluxes ranged from 132.36-1 655.27 ng x (m2 x d)(-1), with an average value of 855.00 ng x (m2 x d)(-1). Weight of PAHs which deposited into Dashiwei Tiankeng was 51.98 g x a(-1), and the dominant PAH compounds are benzo[b] fluoranthene, chrysene, benzo[a] pryene, benzo[k]fluoranthene, anthracene, phenanthrene and naphthalene. Spatial distribution of PAHs around Dashiwei Tiankeng was: the east valley entrance > the south valley entrance > the north valley entrance > the west peak; seasonal variability of PAH depositional fluxes was: spring > summer > autumn > winter. Deposition fluxes of PAHs were 4.6 times higher in spring and summer than those in autumn and winter. The dominant PAH compounds were 4-6 rings PAHs in spring and summer, but the dominant PAH compounds were 2-3 rings PAHs in autumn and winter. PAH depositional fluxes in this study area were closely related with precipitation, wind direction, temperature, wind speed and location of pollution sources. PAHs increased in spring and summer in Dashiwei Karst Tiankeng Group, this could be transported by atmospheric movement from higher air temperature and lower elevation areas where industry developed in Guangxi.

  15. Atmospheric deposition of nitrogen over Czech forests: refinement of estimation of dry deposition for unmeasured nitrogen species

    NASA Astrophysics Data System (ADS)

    Hunova, Iva; Stoklasova, Petra; Kurfurst, Pavel; Vlcek, Ondrej; Schovankova, Jana

    2014-05-01

    The accurate quantification of atmospheric deposition is very important for assessment of ambient air pollution impacts on ecosystems. Our contribution presents an advanced approach to improved quantification of atmospheric deposition of nitrogen over Czech forests, merging available measured data and model results. The ambient air quality monitoring in the Czech Republic is paid an appreciable attention (Hůnová, 2001) due to the fact, that in the recent past its territory belonged to the most polluted parts of Europe (Moldan and Schnoor, 1992). The time trends and spatial patterns of atmospheric deposition were published (Hůnová et al. 2004, Hůnová et al. 2014). Nevertheless, it appears that the atmospheric deposition of nitrogen, particularly the dry deposition, is likely to be underestimated due to unavailability of data of certain nitrogen species as HNO3(g) and NH3. It is known that HNO3(g) may contribute significantly to the dry deposition of nitrogen even in regions with relatively low concentrations (Flechard et al., 2011). We attempted to substitute unmeasured nitrogen species using an Eulerian photochemical dispersion model CAMx, the Comprehensive Air Quality Model with extensions (ESSS, 2011), coupled with a high resolution regional numeric weather prediction model Aladin (Vlček, Corbet, 2011). Preliminary results for 2008 indicate that dry deposition of nitrogen, so far based on detailed monitoring of ambient NOx levels, is underestimated substantially. The dry deposition of N/NOx in 2008 reported by Ostatnická (2009) was about 0.5 g.m-2.year-1 over 99.5 % of the nation-wide area, while the contribution of unmeasured nitrogen species estimated by CAMx model were much higher. To be specific, the dry deposition of N/HNO3(g) accounted for 1.0 g.m-2.year-1, and N/NH3 for 1.6 g.m-2.year-1. In contrast, the deposition of N/HONO (g) with 0.001 g.m-2.year-1, N/PAN with 0.007 g.m-2.year-1, particulate N/NO3- with 0.002 g.m-2.year-1, and particulate N/NH4

  16. Atmospheric acid deposition damage to paints. Environmental research brief

    SciTech Connect

    Haynie, F.H.

    1986-01-01

    Available data from laboratory and field studies of damage to paints by erosion were analyzed to develop an atmospheric acid-deposition damage function for exterior house paints containing calcium carbonate or silicate extenders. Regression-analysis coefficients associated with sulfur dioxide levels are consistent with the reaction between the SO/sub 2/ and calcium carbonate to form soluble calcium sulfate. The effect of sulfuric acid in rain on paint is expected to behave similarly. Observed actual household painting frequencies prior to 1970 are consistent with the damage functions calculated from the experimental erosion data obtained in the 1950's, 1960's and early 1970's. Changes in both environmental conditions and types of paints marketed make it necessary to make assumptions when using the damage functions to estimate costs associated with repainting.

  17. Depositional characteristics of atmospheric polybrominated diphenyl ethers on tree barks

    PubMed Central

    Chun, Man Young

    2014-01-01

    Objectives This study was conducted to determine the depositional characteristics of several tree barks, including Ginkgo (Ginkgo biloba), Pine (Pinus densiflora), Platanus (Platanus), and Metasequoia (Metasequoia glyptostroboides). These were used as passive air sampler (PAS) of atmospheric polybrominated diphenyl ethers (PBDEs). Methods Tree barks were sampled from the same site. PBDEs were analyzed by highresolution gas chromatography/high-resolution mass spectrometer, and the lipid content was measured using the gravimetric method by n-hexane extraction. Results Gingko contained the highest lipid content (7.82 mg/g dry), whereas pine (4.85 mg/g dry), Platanus (3.61 mg/g dry), and Metasequoia (0.97 mg/g dry) had relatively lower content. The highest total PBDEs concentration was observed in Metasequoia (83,159.0 pg/g dry), followed by Ginkgo (53,538.4 pg/g dry), Pine (20,266.4 pg/g dry), and Platanus (12,572.0 pg/g dry). There were poor correlations between lipid content and total PBDE concentrations in tree barks (R2=0.1011, p =0.682). Among the PBDE congeners, BDE 206, 207 and 209 were highly brominated PBDEs that are sorbed to particulates in ambient air, which accounted for 90.5% (84.3-95.6%) of the concentration and were therefore identified as the main PBDE congener. The concentrations of particulate PBDEs deposited on tree barks were dependent on morphological characteristics such as surface area or roughness of barks. Conclusions Therefore, when using the tree barks as the PAS of the atmospheric PBDEs, samples belonging to same tree species should be collected to reduce errors and to obtain reliable data. PMID:25116365

  18. Improving parameterization of gaseous dry deposition in atmospheric chemistry models

    SciTech Connect

    Gao, W.; Wesely, M.L.; Pierce, T.

    1996-12-31

    Realistic description of physical and biological conditions of the Earth`s surface with reasonably small spatial and temporal resolutions are critical for modeling the rate of surface uptake of trace chemical substances. We used satellite remote sensing data recently available over global scales to develop a new dry deposition module that is coupled with spectral reflectance observations derived from the advanced very-high resolution radiometer (AVHRR) on NOAA satellites. The surface conductance for transfer of chemical substances to plant leaves is integrated for total canopy leaf amounts by use of spectral characteristics detected from satellites. The new module is capable of describing spatial variations, seasonal changes, and annual changes in dry deposition over large geographical regions. The current version of the module can be coupled to AVHRR data with a spatial resolution of 15 km by 15 km; advanced Pathfinder AVHRR data with a resolution of 8 km by 8 km will also be used. Work continues on further improving the module`s critical components and making the module operational with regional and global atmospheric chemistry models.

  19. Water Deposition into Titan atmosphere from Saturn's E-ring

    NASA Astrophysics Data System (ADS)

    Juhasz, A.; Horanyi, M.; Kempf, S.; Srama, R.

    2013-12-01

    Cassini's discovery of the geologically active regions on the south polar region of Enceladus allowed the identification of these active plumes as the primary source of Saturn's E-ring. Micron and submicron sized ice particles are supplied from the plumes to sustain the entire E-ring. In situ measurements by the Cassini Cosmic Dust Analyzer (CDA) also led to the recognition that the E-ring extends way beyond its originally recognized limits of 4 - 8 Saturn radii (Rs), reaching beyond 20 Rs, engulfing Titan, Saturn's largest moon. Ice grains entrained in the plumes experience radiation pressure and plasma drag perturbations and their orbits slowly evolve outward. Simultaneously, the ice particles are exposed to energetic ion bombardment, leading to their mass loss due to sputtering. Initially micron sized particles from Enceladus take about 500 years to reach the orbit of Titan, arriving there as approximately 0.1-0.3 micron sized particles. Due to their large eccentricities, these small grains enter Titan's atmosphere with speeds v > 1 km/s,sufficiently fast to ablate, delivering on the order of 5 g/s of water. This presentation will discuss the resulting profiles of water vapor deposition rates as function of altitude in Titan's atmosphere.

  20. Atmospheric deposition of methanol over the Atlantic Ocean.

    PubMed

    Yang, Mingxi; Nightingale, Philip D; Beale, Rachael; Liss, Peter S; Blomquist, Byron; Fairall, Christopher

    2013-12-10

    In the troposphere, methanol (CH3OH) is present ubiquitously and second in abundance among organic gases after methane. In the surface ocean, methanol represents a supply of energy and carbon for marine microbes. Here we report direct measurements of air-sea methanol transfer along a ∼10,000-km north-south transect of the Atlantic. The flux of methanol was consistently from the atmosphere to the ocean. Constrained by the aerodynamic limit and measured rate of air-sea sensible heat exchange, methanol transfer resembles a one-way depositional process, which suggests dissolved methanol concentrations near the water surface that are lower than what were measured at ∼5 m depth, for reasons currently unknown. We estimate the global oceanic uptake of methanol and examine the lifetimes of this compound in the lower atmosphere and upper ocean with respect to gas exchange. We also constrain the molecular diffusional resistance above the ocean surface-an important term for improving air-sea gas exchange models.

  1. Atmospheric deposition of methanol over the Atlantic Ocean

    PubMed Central

    Yang, Mingxi; Nightingale, Philip D.; Beale, Rachael; Liss, Peter S.; Blomquist, Byron; Fairall, Christopher

    2013-01-01

    In the troposphere, methanol (CH3OH) is present ubiquitously and second in abundance among organic gases after methane. In the surface ocean, methanol represents a supply of energy and carbon for marine microbes. Here we report direct measurements of air–sea methanol transfer along a ∼10,000-km north–south transect of the Atlantic. The flux of methanol was consistently from the atmosphere to the ocean. Constrained by the aerodynamic limit and measured rate of air–sea sensible heat exchange, methanol transfer resembles a one-way depositional process, which suggests dissolved methanol concentrations near the water surface that are lower than what were measured at ∼5 m depth, for reasons currently unknown. We estimate the global oceanic uptake of methanol and examine the lifetimes of this compound in the lower atmosphere and upper ocean with respect to gas exchange. We also constrain the molecular diffusional resistance above the ocean surface—an important term for improving air–sea gas exchange models. PMID:24277830

  2. Atmospheric nitrogen deposition and its long-term dynamics in a southeast China coastal area.

    PubMed

    Chen, Nengwang; Hong, Huasheng; Huang, Quanjia; Wu, Jiezhong

    2011-06-01

    Measurements were conducted during 2004-2005 and 2009-2010 to characterize atmospheric nitrogen (N) deposition to the Jiulong River Estuary - Xiamen Bay area in southeast China. Isotopic analysis and long-term data (1990-2009) for inorganic N extracted from the national acid deposition dataset were used to determine the dominant source of atmospheric nitrate and N component dynamics. The results showed that the mean dissolved total N concentration in rain water for the three coastal area sites was 2.71 ± 1.58 mg N L(-1) (n = 141) in 2004. The mean dissolved inorganic N at the Xiamen site was 1.62 ± 1.19 mg N L(-1) (n = 46) in 2004-2005 and 1.56 ± 1.39 mg N L(-1) (n = 36) in 2009-2010, although the difference is not significant, nitrate turnover dominates the N component in the latter period. Total deposition flux over Xiamen was 30 kg N ha(-1) yr(-1), of which dry and wet deposition contributed 16% and 84%, respectively. Nitrate in wet deposition with low isotopic value (between -3.05 and -7.48‰) was likely to have mostly originated from combustion NO(x) from vehicle exhausts. The inorganic N in acid deposition exhibited a significant increase (mainly for nitrate) since the mid-1990s, which is consistent with the increased gaseous concentrations of NO(x) and expanding number of automobiles in the coastal city (Xiamen). The time series of nitrate anions and ammonium cations as well as pH values during the period 1990-2009 reflected an increasing trend of N emission with potential implication for N-induced acidification.

  3. The effect of four landscape features on atmospheric deposition to Hunter Mountain, New York

    SciTech Connect

    Weathers, K.C.

    1993-01-01

    Atmospheric deposition to montane ecosystems is higher than to adjacent lowlands. Because of the heterogeneous nature of mountainous landscapes, rates of deposition are likely to vary considerably with major landscape features. Estimates of total atmospheric deposition for mountains in the northeastern United States are wide-ranging and based on models that do not take into account landscape heterogeneity. Little had been known about the spatial variability of atmospheric deposition to these high elevation ecosystems. On Hunter Mountain in the Catskill Mountains, New York, four landscape features-(1) edges/gaps, (2) elevation, (3) aspect and (4) vegetation type-were identified as likely to control atmospheric deposition in mountainous terrain. Relative rates of atmospheric deposition, or enhancement factors, were measured across these landscape features by using lead in the forest floor as an indicator of total deposition, and, in the case of forest edges, also by making direct measurements of cloudwater deposition. These enhancement factors were used to model deposition to the Hunter Mountain landscape. Average deposition to the area above 1000 m was estimated to be 13% greater than to a nearby low elevation site. [open quotes]Hotspots[close quotes] were identified at high elevation, conifer forest edges where atmospheric deposition of pollutants and nutrients is up to 300% greater than a low-elevation forest. More detailed measurements of cloudwater deposition to an edge of a high elevation spruce forest revealed enhancement from 0- to 15-fold over the interior, with an average 3-fold increase. Sulfate flux in throughfall during cloud events was found to mirror cloudwater deposition and may be a useful tool to quantify patterns of atmospheric deposition in mountains. The data suggest current estimates of atmospheric deposition to mountainous terrain that do not include landscape heterogeneity may seriously underestimate loading of pollutants and nutrients.

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

    NASA Astrophysics Data System (ADS)

    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 < 1 μm (PM1), 1-10 μm (PM1-10), and > 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    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 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 μm (PM1), 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 different regions of the

  6. Observational constraints of Polar Ice Deposits on Mars Atmospheric GCMs

    NASA Astrophysics Data System (ADS)

    Teodoro, L. F. A.; Elphic, R. C.; Hollingsworth, J. L.; Haberle, R. M.; Kahre, M. A.; Eke, V. R.; Roush, T. L.; Marzo, G. A.; Brown, A. J.; Feldman, W. C.; Maurice, S.

    2012-04-01

    Much of our current knowledge about Mars' climate and atmospheric global circulation stems from measurements taken by landers and orbiters. Thus for many years the details of the atmospheric circulation were studied using numerical global circulation models (GCMs) that have been successful in reproducing most of the available observations [1]. More than ever, GCMs will play a central role in analyzing the existing data and in planning and execution of upcoming missions. The Mars Odyssey Neutron Spectrometer (MONS) has enabled a comprehensive study of the overall distribution of hydrogen in the surface of Mars [2]. Deposits ranging between 20% and 100% Water-Equivalent Hydrogen (WEH) by mass are found pole-ward of 55 deg. latitude, while less H-rich deposits are found at lower latitudes. These results assume that the H distribution is uniform in the top meter of the martian soil. The Mars Reconnaissance Orbiter-Compact Reconnaissance Imaging Spectrometer for Mars (MRO-CRISM) has identified numerous locations on Mars where hydrous minerals occur [3]. The information collected by MRO-CRISM samples the top few mm's to cm's of the surface. This independent information can impose additional constrains on the 3-D H distribution inferred from the MONS data. For instance, the absence of a correlation between WEH wt% drawn from the MONS and CRISM data at a location where the neutron data indicate high WEH implies the presence of a 3-D structure that is characterized by a top layer with a low abundance of water, either ice or hydrated minerals, and some buried layers where the concentration of H is higher than that expected in a uniformly mixed layer. However, the spatial resolution of MONS and MRO-CRISM are ~550 km and ~20-200m, respectively. Hence, one must assure the MRO-CRISM and MONS data are on the same scales. The MRO-CRISM data can be re-binned to lower resolution, but additionally the MONS instrumental smearing must be properly understood and removed. Usually, in the

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Patterns of atmospheric deposition to a mountain landscape in southeastern New York

    SciTech Connect

    Weathers, K.C.; Lovett, G.M.; Likens, G.E. )

    1994-06-01

    We postulate that in the Catskill Mts., of southeastern NY, patterns of atmospheric deposition across the landscape are regulated primarily by four landscape features: (1) edges and gaps; (2) elevation; (3) slope aspect; and (4) vegetation type. We measured relative rates of deposition associated with these features using Pb in the forest floor as an indicator of total deposition. Deposition enhancement factors generated by these measurements were used in a geographic information system to model deposition to the landscape of Hunter Mt. Average deposition in the area above 1000m elevation was estimated to be 13% greater than to nearby low-elevation sites. Combinations of the landscape features can create [open quotes]hotspots[close quotes] of deposition, for instance, high-elevation coniferous forest edges, where deposition can be 300% greater than to a low-elevation forest. These results illustrate the importance of considering landscape-level variation when modeling atmospheric deposition or extrapolating deposition measurements.

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

    PubMed

    Yu, Xue; Driscoll, Charles T; Huang, Jiaoyan; Holsen, Thomas M; Blackwell, Bradley D

    2013-01-01

    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).

  11. Chemical instrumentation for field studies of atmospheric wet deposition processes

    SciTech Connect

    Tanner, R.L.

    1986-04-01

    Field studies of wet deposition processes require the differentiation and determination of many trace reactive species in the atmosphere. The species may be present in clear-air-gaseous or aerosol phases, or they may be distributed between cloudwater or precipitation and interstitial gaseous phases. Analytical requirement on existing techniques have been extremely rigorous and, in several cases, have required development of new approaches to the sampling and determination of critical species. This paper views these developments with respect to airborne sampling in the following general areas: determination of sub-ppb levels of nitrogen oxides (NO, NO/sub x/, HNO/sub 3/) in real-time using ozone chemiluminescence; determination of sub-ppb levels of sulfur dioxide and aersol sulfate in real-time using the flame photometric detector; determination of oxidants (ozone, PAN, H/sub 2/O/sub 2/) in gaseous and aqueous phases; determination of organic species (hydrocarbons, aldehydes, acids in gaseous and aqueous phases; cloud/raindrop - free air sampling; collection of aqueous liquid and solid samples; direct measurement of particle size distributions (aerosols, cloud droplets, rain droplets.)

  12. The Measurement of Atmospheric Concentrations and Deposition of Semi-Volatile Organic Compounds.

    ERIC Educational Resources Information Center

    Lee, David S.; Nicholson, Ken W.

    1994-01-01

    Provides a physical description of semivolatile organic compounds (SVOCs), both in terms of their characteristic nature in the atmosphere and the processes which control their deposition. Contains a summary of the requirements for a full assessment of atmospheric SVOCs and their deposition. (LZ)

  13. Nitrogen Deposition Effects on Diatom Communities in Lakes from Three National Parks in Washington State.

    PubMed

    Sheibley, Richard W; Enache, Mihaela; Swarzenski, Peter W; Moran, Patrick W; Foreman, James R

    2014-01-01

    The goal of this study was to document if lakes in National Parks in Washington have exceeded critical levels of nitrogen (N) deposition, as observed in other Western States. We measured atmospheric N deposition, lake water quality, and sediment diatoms at our study lakes. Water chemistry showed that our study lakes were ultra-oligotrophic with ammonia and nitrate concentrations often at or below detection limits with low specific conductance (<100 μS/cm), and acid neutralizing capacities (<400 μeq/L). Rates of summer bulk inorganic N deposition at all our sites ranged from 0.6 to 2.4 kg N ha(-1) year(-1) and were variable both within and across the parks. Diatom assemblages in a single sediment core from Hoh Lake (Olympic National Park) displayed a shift to increased relative abundances of Asterionella formosa and Fragilaria tenera beginning in the 1969-1975 timeframe, whereas these species were not found at the remaining (nine) sites. These diatom species are known to be indicative of N enrichment and were used to determine an empirical critical load of N deposition, or threshold level, where changes in diatom communities were observed at Hoh Lake. However, N deposition at the remaining nine lakes does not seem to exceed a critical load at this time. At Milk Lake, also in Olympic National Park, there was some evidence that climate change might be altering diatom communities, but more research is needed to confirm this. We used modeled precipitation for Hoh Lake and annual inorganic N concentrations from a nearby National Atmospheric Deposition Program station, to calculate elevation-corrected N deposition for 1980-2009 at Hoh Lake. An exponential fit to this data was hindcasted to the 1969-1975 time period, and we estimate a critical load of 1.0 to 1.2 kg N ha(-1) year(-1) for wet deposition for this lake.

  14. Discovering the causes, consequences, and implications of acid rain and atmospheric deposition

    SciTech Connect

    Cowling, E.B.

    1983-09-01

    Most forest industry personnel concerned with environmental issues are located at mill sites, where the major focus of their concern is with emissions and regulations rather than with deposition and its effects. The forest products industry needs to think of itself as a net receiver rather than a primary emitter of air pollution, acid rain, and atmospheric deposition. A shift in focus to include research on the chemistry of atmospheric deposition and both beneficial and detrimental effects on forest productivity and water quality is recommended. An attempt is made to summarize some important principles concerning air pollution, acid deposition, and atmospheric deposition and their effects on terrestrial and aquatic ecosystems. The effects on water quality, agricultural crops, forests, and soils are examined. Recent federal coordinated research programs that have been developed on the biological and atmospheric aspects of the acid deposition problem are presented.

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

    NASA Astrophysics Data System (ADS)

    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

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

    USGS Publications Warehouse

    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

  17. Integrated Assessment of Ecosystem Effects of Atmospheric Deposition

    EPA Science Inventory

    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...

  18. Nitrogen deposition effects on diatom communities in lakes from three National Parks in Washington State

    USGS Publications Warehouse

    Sheibley, Richard W.; Enache, Mihaela; Swarzenski, Peter W.; Moran, Patrick W.; Foreman, James R.

    2014-01-01

    The goal of this study was to document if lakes in National Parks in Washington have exceeded critical levels of nitrogen (N) deposition, as observed in other Western States. We measured atmospheric N deposition, lake water quality, and sediment diatoms at our study lakes. Water chemistry showed that our study lakes were ultra-oligotrophic with ammonia and nitrate concentrations often at or below detection limits with low specific conductance (−1 year−1 and were variable both within and across the parks. Diatom assemblages in a single sediment core from Hoh Lake (Olympic National Park) displayed a shift to increased relative abundances of Asterionella formosa and Fragilaria tenera beginning in the 1969–1975 timeframe, whereas these species were not found at the remaining (nine) sites. These diatom species are known to be indicative of N enrichment and were used to determine an empirical critical load of N deposition, or threshold level, where changes in diatom communities were observed at Hoh Lake. However, N deposition at the remaining nine lakes does not seem to exceed a critical load at this time. At Milk Lake, also in Olympic National Park, there was some evidence that climate change might be altering diatom communities, but more research is needed to confirm this. We used modeled precipitation for Hoh Lake and annual inorganic N concentrations from a nearby National Atmospheric Deposition Program station, to calculate elevation-corrected N deposition for 1980–2009 at Hoh Lake. An exponential fit to this data was hindcasted to the 1969–1975 time period, and we estimate a critical load of 1.0 to 1.2 kg N ha−1 year−1 for wet deposition for this lake.

  19. Atmospheric deposition of mercury and major ions to the Pensacola (Florida) watershed: spatial, seasonal, and inter-annual variability

    NASA Astrophysics Data System (ADS)

    Caffrey, J. M.; Landing, W. M.; Nolek, S. D.; Gosnell, K. J.; Bagui, S. S.; Bagui, S. C.

    2010-06-01

    Atmospheric deposition was measured at three sites in the Pensacola Bay watershed, Florida, between November 2004 and December 2007. Mercury deposition in the Pensacola Bay watershed was similar to that from nearby Mercury Deposition Network sites along the Northern Gulf of Mexico coast. Mercury deposition during the summer months is higher than other months due to higher concentrations in rainfall throughout the region. Deposition of constituents like H+, sulfate, nitrate, ammonium, chloride and sodium, were much higher in Pensacola Bay that at National Atmospheric Deposition Program (NADP) sites. Chloride and sodium deposition are higher because Pensacola Bay sites are closer to the Gulf of Mexico which is a source of sea salt aerosols. Acid rain constituents, H+, sulfate, nitrate and ammonium are most likely higher at Pensacola Bay sites because these sites are much closer to emission sources of these constituents than NADP sites, particularly two Florida NADP sites, FL14 and FL23, which are located in rural counties far from major industrial activities.

  20. Effects of collector types in sampling of atmospheric depositional fluxes.

    PubMed

    Dueñas, C; Fernández, M C; Cañete, S; Pérez Barea, J J; Pérez, M

    2009-02-01

    The bulk gross alpha, gross beta and (7)Be depositional fluxes were measured in Málaga (36.7 degrees N, 4.5 degrees W), a coastal Mediterranean station in the south of Spain for one whole year. In order to quantify the local variation of deposition rates, we have analysed the monthly results from two deposition collectors: a "pot "collector with a continuous water-covered surface and a "funnel" collector. In general, the alpha and beta depositional fluxes from the funnel collector were approximately two times lower than the pot collector. Whereas for the cosmogenic (7)Be, the depositional flux of (7)Be from funnel collector was also approximately two times lower than the pot collector. A good correlation of the depositional flux of (7)Be has been obtained from both collectors.

  1. 75 FR 22047 - Intent To Initiate Consultation and Coordinate the National Oceanic and Atmospheric...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-27

    ... National Oceanic and Atmospheric Administration 15 CFR Part 922 Intent To Initiate Consultation and Coordinate the National Oceanic and Atmospheric Administration's Responsibilities Under Section 106 of the... National Marine Sanctuaries (ONMS), National Ocean Service (NOS), National Oceanic and......

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

    PubMed

    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.

  3. Can sulfate fluxes in forest canopy throughfall be used to estimate atmospheric sulfur deposition

    SciTech Connect

    Lindberg, S.E.; Garten, C.T. Jr. ); Cape, J.N. ); Ivens, W. )

    1991-01-01

    The flux of sulfate is forest throughfall and stemflow (the sum of which is designated here as TF) may be an indicator of the atmospheric deposition of S, particularly if foliar leaching of internal plant S is small relative to washoff of deposition. Extensive data from 13 forests indicate that annual sulfate fluxes in TF and in atmospheric deposition are very similar, and recent studies with {sup 35}S tracers indicate that leaching is only a few percent of total TF. However, some short-term deposition/TF comparisons show large differences, and there remain questions about interpretation of tracer results. Considering the data, we conclude that TF may be used under some conditions to estimate deposition within acceptable uncertainty limits, but that some assumptions need further testing. If TF does reflect deposition, these data suggest that commonly used methods and models seriously underestimate total S deposition at some sites. 39 refs. ,4 figs., 1 tab.

  4. Glacial ice composition: A potential long-term record of the chemistry of atmospheric deposition, Wind River Range, Wyoming

    SciTech Connect

    Naftz, D.L. ); Rice, J.A. ); Ranville, J.R. )

    1991-06-01

    During a reconnaissance study, ice samples were collected from Knife Point glacier to determine if glaciers in the Wind River Range Could provide a long-term record of the chemical composition of wet deposition. Eight annual ice layers comprising the years 1980-1987 were identified. The concentration of calcium, chloride, and sulfate in the annual-weighted wet deposition samples collected at the National Atmospheric deposition Program (NADP) station near Pinedale, Wyoming, showed a significant, positive correlation to the concentration of the same major ions in composite samples from the annual ice layers. results of the study imply that continuous ice cores reaching to the deeper parts of glaciers in the Wind River Range could provide long-term records of the chemical composition of wet deposition.

  5. Thresholds for protecting Pacific Northwest ecosystems from atmospheric deposition of nitrogen: state of knowledge report

    USGS Publications Warehouse

    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.

  6. Direct measurements of atmospheric iron, cobalt, and aluminum-derived dust deposition at Kerguelen Islands

    NASA Astrophysics Data System (ADS)

    Heimburger, A.; Losno, R.; Triquet, S.; Dulac, F.; Mahowald, N.

    2012-12-01

    Atmospheric deposition is one of the major sources of nutrients bringing trace metals to remote marine biota. In this study, total atmospheric deposition and crustal aerosol concentrations were monitored at Kerguelen Islands (49°18'S; 70°07'E) in the Southern Ocean during a short campaign in early 2005 and then continuously for about 2 years (2009-2010). Results show very low levels of atmospheric dust and trace metals concentrations but higher deposition fluxes than expected. The averaged total dust deposition flux as derived from Al deposition measurements is 659 μg m-2 d-1. Simultaneously measured Fe and Co deposition fluxes are respectively 29 μg m-2 d-1 (520 nmol m-2 d-1) and 0.014 μg m-2 d-1 (0.24 nmol m-2 d-1), giving typically crustal elemental ratios to Al of 0.54 and 2.6 10-4. Measured dust deposition is in relatively good agreement with those simulated by current atmospheric models, but suggest that previous indirect calculations from field experiments are too low by a factor of 20. Observations and model results show that dust is transported above the marine atmospheric boundary layer to Kerguelen Islands, and thus that surface concentrations are not representative of the total dust column. Indeed, using surface concentrations leads to very large computed wet scavenging ratios, and to the conclusion that it is not appropriate to derive deposition fluxes from surface concentrations at remote ocean sites.

  7. Storms, polar deposits and the methane cycle in Titan's atmosphere.

    PubMed

    Griffith, Caitlin Ann

    2009-02-28

    In Titan's atmosphere, the second most abundant constituent, methane, exists as a gas, liquid and solid, and cycles between the atmosphere and the surface. Similar to the Earth's hydrological cycle, Titan sports clouds, rain and lakes. Yet, Titan's cycle differs dramatically from its terrestrial counterpart, and reveals the workings of weather in an atmosphere that is 10 times thicker than the Earth's atmosphere, that is two orders of magnitude less illuminated, and that involves a different condensable. While ongoing measurements by the Cassini-Huygens mission are revealing the intricacies of the moon's weather, circulation, lake coverage and geology, knowledge is still limited by the paucity of observations. This review of Titan's methane cycle therefore focuses on measured characteristics of the lower atmosphere and surface that appear particularly perplexing or alien.

  8. Temporal Variation in Atmospheric Phosphorus Transport and Deposition to the Yucatan Peninsula: Local and Remote Sources

    NASA Astrophysics Data System (ADS)

    Das, R.

    2011-12-01

    Atmospheric phosphorus (P) inputs are rarely considered in models of terrestrial P cycling, but may be critical in balancing losses of P from ecosystems over the long-term, especially in the tropics. Several authors have suggested that forests in the Amazon basin, Hawaiian and Caribbean islands may be sustained by atmospheric P inputs from long-distance dust transport and other sources, but relatively few studies combine field measurements in a region with remote sensing or modeling approaches to quantify atmospheric P inputs. We use measurements of P in atmospheric bulk deposition collected periodically between 2006 and 2011 in a tropical dry forest in the southern Yucatan peninsula and compare these with remote sensing and atmospheric transport modeling estimates. There is a seasonal pattern in P deposition, with the greatest deposition occurring between April and August, when local biomass burning is greatest. Saharan dust transport to the region occurs between June and August, and is an important contributor to atmospheric P deposition. There is also interannual variation in atmospheric P deposition that is driven by variations in biomass burning and dust transport. We evaluate the importance of long-distance dust transport to the Yucatan as a source of P relative to other atmospheric inputs and losses, and its importance to ecosystem productivity.

  9. Climate, not atmospheric deposition, drives the biogeochemical mass-balance of a mountain watershed

    USGS Publications Warehouse

    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.

  10. Atmospheric deposition of mercury and major ions to the Pensacola Bay (Florida) watershed: spatial, seasonal, and inter-annual variability

    NASA Astrophysics Data System (ADS)

    Caffrey, J. M.; Landing, W. M.; Nolek, S. D.; Gosnell, K.; Bagui, S. S.; Bagui, S. C.

    2010-02-01

    Atmospheric deposition was measured at three sites in the Pensacola Bay watershed, Florida, between November 2004 and December 2007. Mercury deposition in the Pensacola Bay watershed was similar to that from nearby Mercury Deposition Network sites along the Northern Gulf of Mexico coast. Mercury deposition during the summer months is higher than other months due to higher concentrations in rainfall throughout the region. Deposition of constituents like H+, sulfate, nitrate, ammonium, chloride and sodium, were much higher in Pensacola Bay that at National Atmospheric Deposition Program (NADP) sites. Chloride and sodium fluxes are higher because Pensacola Bay sites are closer to the Gulf of Mexico which is a source of sea salt aerosols. Acid rain constituents, H+, sulfate, nitrate and ammonium are most likely higher at Pensacola Bay sites because these sites are much closer to emission sources of these constituents than NADP sites, particularly two Florida NADP sites, FL14 and FL23, which are located in rural counties far from major industrial activities.

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    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 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 their increases in

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

    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

  14. ESTIMATING GASEOUS EXCHANGES BETWEEN THE ATMOSPHERE AND PLANTS USING A COUPLED BIOCHEMICAL DRY DEPOSITION MODEL

    EPA Science Inventory

    To study gaseous exchanges between the soil, biosphere and atmosphere, a biochemical model was coupled with the latest version of Meyers Multi-Layer Deposition Model. The biochemical model describes photosynthesis and respiration and their coupling with stomatal resistance for...

  15. ATMOSPHERIC MERCURY SIMULATION USING THE CMAQ MODEL: FORMULATION DESCRIPTION AND ANALYSIS OF WET DEPOSITION RESULTS

    EPA Science Inventory

    The Community Multiscale Air Quality (CMAQ) modeling system has recently been adapted to simulate the emission, transport, transformation and deposition of atmospheric mercury in three distinct forms; elemental mercury gas, reactive gaseous mercury, and particulate mercury. Emis...

  16. Atmospheric deposition and solute export in giant sequoia: mixed conifer watersheds in the Sierra Nevada, California

    USGS Publications Warehouse

    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+.

  17. Chinese coastal seas are facing heavy atmospheric nitrogen deposition

    NASA Astrophysics Data System (ADS)

    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.

  18. Modeling atmospheric deposition using a stochastic transport model

    SciTech Connect

    Buckley, R.L.

    1999-12-17

    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.

  19. The significance of the episodic nature of atmospheric deposition to Low Nutrient Low Chlorophyll regions

    NASA Astrophysics Data System (ADS)

    Guieu, C.; Aumont, O.; Paytan, A.; Bopp, L.; Law, C. S.; Mahowald, N.; Achterberg, E. P.; Marañón, E.; Salihoglu, B.; Crise, A.; Wagener, T.; Herut, B.; Desboeufs, K.; Kanakidou, M.; Olgun, N.; Peters, F.; Pulido-Villena, E.; Tovar-Sanchez, A.; Völker, C.

    2014-11-01

    In the vast Low Nutrient Low-Chlorophyll (LNLC) Ocean, the vertical nutrient supply from the subsurface to the sunlit surface waters is low, and atmospheric contribution of nutrients may be one order of magnitude greater over short timescales. The short turnover time of atmospheric Fe and N supply (<1 month for nitrate) further supports deposition being an important source of nutrients in LNLC regions. Yet, the extent to which atmospheric inputs are impacting biological activity and modifying the carbon balance in oligotrophic environments has not been constrained. Here, we quantify and compare the biogeochemical impacts of atmospheric deposition in LNLC regions using both a compilation of experimental data and model outputs. A metadata-analysis of recently conducted field and laboratory bioassay experiments reveals complex responses, and the overall impact is not a simple "fertilization effect of increasing phytoplankton biomass" as observed in HNLC regions. Although phytoplankton growth may be enhanced, increases in bacterial activity and respiration result in weakening of biological carbon sequestration. The application of models using climatological or time-averaged non-synoptic deposition rates produced responses that were generally much lower than observed in the bioassay experiments. We demonstrate that experimental data and model outputs show better agreement on short timescale (days to weeks) when strong synoptic pulse of aerosols deposition, similar in magnitude to those observed in the field and introduced in bioassay experiments, is superimposed over the mean atmospheric deposition fields. These results suggest that atmospheric impacts in LNLC regions have been underestimated by models, at least at daily to weekly timescales, as they typically overlook large synoptic variations in atmospheric deposition and associated nutrient and particle inputs. Inclusion of the large synoptic variability of atmospheric input, and improved representation and

  20. 77 FR 74174 - National Oceanic and Atmospheric Administration (NOAA) National Climate Assessment and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-13

    ... National Oceanic and Atmospheric Administration (NOAA) National Climate Assessment and Development Advisory... notice sets forth the schedule of a forthcoming meeting of the DoC NOAA National Climate Assessment and... the call. Please check the National Climate Assessment Web site for additional information at...

  1. Improved Formulations for Air-Surface Exchanges Related to National Security Needs: Dry Deposition Models

    SciTech Connect

    Droppo, James G.

    2006-07-01

    The Department of Homeland Security and others rely on results from atmospheric dispersion models for threat evaluation, event management, and post-event analyses. The ability to simulate dry deposition rates is a crucial part of our emergency preparedness capabilities. Deposited materials pose potential hazards from radioactive shine, inhalation, and ingestion pathways. A reliable characterization of these potential exposures is critical for management and mitigation of these hazards. A review of the current status of dry deposition formulations used in these atmospheric dispersion models was conducted. The formulations for dry deposition of particulate materials from am event such as a radiological attack involving a Radiological Detonation Device (RDD) is considered. The results of this effort are applicable to current emergency preparedness capabilities such as are deployed in the Interagency Modeling and Atmospheric Assessment Center (IMAAC), other similar national/regional emergency response systems, and standalone emergency response models. The review concludes that dry deposition formulations need to consider the full range of particle sizes including: 1) the accumulation mode range (0.1 to 1 micron diameter) and its minimum in deposition velocity, 2) smaller particles (less than .01 micron diameter) deposited mainly by molecular diffusion, 3) 10 to 50 micron diameter particles deposited mainly by impaction and gravitational settling, and 4) larger particles (greater than 100 micron diameter) deposited mainly by gravitational settling. The effects of the local turbulence intensity, particle characteristics, and surface element properties must also be addressed in the formulations. Specific areas for improvements in the dry deposition formulations are 1) capability of simulating near-field dry deposition patterns, 2) capability of addressing the full range of potential particle properties, 3) incorporation of particle surface retention/rebound processes, and

  2. Current and Future Deposition of Reactive Nitrogen to United States National Parks

    NASA Astrophysics Data System (ADS)

    Ellis, R.; Jacob, D. J.; Zhang, L.; Payer, M.; Holmes, C. D.; Schichtel, B. A.

    2012-12-01

    The concentrations of reactive nitrogen species in the atmosphere have been altered by anthropogenic activities such as fossil fuel combustion and agriculture. The United States National Parks are protected areas wherein the natural habitat is to be conserved for future generations. However, deposition of reactive nitrogen (N) to terrestrial and aquatic ecosystems can lead to changes, some of which may not be reversible. We investigate the deposition of N to U.S. National Parks using the GEOS-Chem chemical transport model with 0.5 x 0.667 degree resolution over North America. We compare the annual nitrogen deposition for each park to a critical load, above which significant harmful effects on specific ecosystem elements are likely to occur. For our base year 2006, we find 9 parks to be in exceedance of their critical load, mainly located in the east where N deposition can reach up to 25 kg N per hectare per year. Future changes in N deposition are also investigated using the IPCC Representative Concentration Pathway (RCP) emission scenarios for 2050. We use RCP8.5 as a "business-as-usual" scenario for N deposition and find that under this emission scenario, 18 parks are predicted to be in exceedance of their critical loads by the year 2050. Most of this increase in N deposition is due to increases in the emissions of ammonia. RCP4.5 was used as a more optimistic scenario but we still find 12 parks in exceedance of their critical loads. This work suggests that in order to meet N deposition critical load goals in U.S. National Parks, policy-makers should consider regulations on ammonia.

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

    NASA Astrophysics Data System (ADS)

    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

  4. Sources and deposition of polycyclic aromatic hydrocarbons to Western U.S. national parks.

    PubMed

    Usenko, Sascha; Simonich, Staci L Massey; Hageman, Kimberly J; Schrlau, Jill E; Geiser, Linda; Campbell, Don H; Appleby, Peter G; Landers, Dixon H

    2010-06-15

    Seasonal snowpack, lichens, and lake sediment cores were collected from fourteen lake catchments in eight western U.S. National Parks and analyzed for sixteen polycyclic aromatic hydrocarbons (PAHs) to determine their current and historical deposition, as well as to identify their potential sources. Seasonal snowpack was measured to determine the current wintertime atmospheric PAH deposition; lichens were measured to determine the long-term, year around deposition; and the temporal PAH deposition trends were reconstructed using lake sediment cores dated using (210)Pb and (137)Cs. The fourteen remote lake catchments ranged from low-latitude catchments (36.6 degrees N) at high elevation (2900 masl) in Sequoia National Park, CA to high-latitude catchments (68.4 degrees N) at low elevation (427 masl) in the Alaskan Arctic. Over 75% of the catchments demonstrated statistically significant temporal trends in SigmaPAH sediment flux, depending on catchment proximity to source regions and topographic barriers. The SigmaPAH concentrations and fluxes in seasonal snowpack, lichens, and surficial sediment were 3.6 to 60,000 times greater in the Snyder Lake catchment of Glacier National Park than the other 13 lake catchments. The PAH ratios measured in snow, lichen, and sediment were used to identify a local aluminum smelter as a major source of PAHs to the Snyder Lake catchment. These results suggest that topographic barriers influence the atmospheric transport and deposition of PAHs in high-elevation ecosystems and that PAH sources to these national park ecosystems range from local point sources to diffuse regional and global sources.

  5. Sources and Deposition of Polycyclic Aromatic Hydrocarbons to Western U.S. National Parks

    PubMed Central

    USENKO, SASCHA; MASSEY SIMONICH, STACI L.; HAGEMAN, KIMBERLY J.; SCHRLAU, JILL E.; GEISER, LINDA; CAMPBELL, DON H.; APPLEBY, PETER G.; LANDERS, DIXON H.

    2010-01-01

    Seasonal snowpack, lichens, and lake sediment cores were collected from fourteen lake catchments in eight western U.S. National Parks and analyzed for sixteen polycyclic aromatic hydrocarbons (PAHs) in order to determine their current and historical deposition, as well as to identify their potential sources. Seasonal snowpack was measured to determine the current wintertime atmospheric PAH deposition; lichens were measured to determine the long-term, year around deposition; and the temporal PAH deposition trends were reconstructed using lake sediment cores dated using 210Pb and 137Cs. The fourteen remote lake catchments ranged from low-latitude catchments (36.6° N) at high elevation (2900 masl) in Sequoia National Park, CA to high-latitude catchments (68.4° N) at low elevation (427 masl) in the Alaskan Arctic. Over 75% of the catchments demonstrated statistically significant temporal trends in ΣPAH sediment flux, depending on catchment proximity to source regions and topographic barriers. The ΣPAH concentrations and fluxes in seasonal snowpack, lichens, and surficial sediment were 3.6 to 60,000 times greater in the Snyder Lake catchment of Glacier National Park than the other 13 lake catchments. The PAH ratios measured in snow, lichen, and sediment were used to identify a local aluminum smelter as a major source of PAHs to the Snyder Lake catchment. These results suggest that topographic barriers influence the atmospheric transport and deposition of PAHs in high-elevation ecosystems and that PAH sources to these national park ecosystems range from local point sources to diffuse regional and global sources. PMID:20465303

  6. Nitrogen deposition to lakes in national parks of the western Great Lakes region: Isotopic signatures, watershed retention, and algal shifts

    NASA Astrophysics Data System (ADS)

    Hobbs, William O.; Lafrancois, Brenda Moraska; Stottlemyer, Robert; Toczydlowski, David; Engstrom, Daniel R.; Edlund, Mark B.; Almendinger, James E.; Strock, Kristin E.; VanderMeulen, David; Elias, Joan E.; Saros, Jasmine E.

    2016-03-01

    Atmospheric deposition is a primary source of reactive nitrogen (Nr) to undisturbed watersheds of the Great Lakes region of the U.S., raising concerns over whether enhanced delivery over recent decades has affected lake ecosystems. The National Atmospheric Deposition Program (NADP) has been measuring Nr deposition in this region for over 35 years. Here we explore the relationships among NADP-measured Nr deposition, nitrogen stable isotopes (δ15N) in lake sediments, and the response of algal communities in 28 lakes situated in national parks of the western Great Lakes region of the U.S. We find that 36% of the lakes preserve a sediment δ15N record that is statistically correlated with some form of Nr deposition (total dissolved inorganic N, nitrate, or ammonium). Furthermore, measured long-term (since 1982) nitrogen biogeochemistry and inferred critical nitrogen loads suggest that watershed nitrogen retention and climate strongly affect whether sediment δ15N is related to Nr deposition in lake sediment records. Measurements of algal change over the last ~ 150 years suggest that Nr deposition, in-lake nutrient cycling, and watershed inputs are important factors affecting diatom community composition, in addition to direct climatic effects on lake physical limnology. The findings suggest that bulk sediment δ15N does reflect Nr deposition in some instances. In addition, this study highlights the interactive effects of Nr deposition and climate variability.

  7. Acid deposition: Atmospheric processes in Eastern North America

    SciTech Connect

    Not Available

    1983-01-01

    This report examines scientific evidence on the relationship between emissions of acid-forming pollutants and damage to sensitive ecosystems from acid rain and other forms of acid deposition. The report's conclusions represent the most authoritative statement yet that reductions in emissions of these pollutants will result in proportional reductions in acid rain.

  8. Interactions of atmospheric deposition with coniferous canopies in Estonia.

    PubMed

    Pajuste, K; Frey, J; Asi, E

    2006-01-01

    Throughfall and open field bulk precipitation were measured at three coniferous sites during 1995-2002 in the framework of ICP Integrated Monitoring and at five coniferous sites during 1996-2002 in the framework of ICP Forests (Level II). The coniferous canopies acted as a sink for nitrate and ammonium and as a source for base cations: Ca(2+), Mg(2+) and K(+). The estimated share of SO(4)-S dry deposition from total deposition was 1.5-4 times higher for dormant period compared to growing period. During the study period average annual throughfall and bulk deposition of SO(4)-S decreased significantly, 2.8 and 2.3 times, respectively. Throughfall enrichment with base cations increased in the order Mg < Na < Ca < K. Using Na as a tracer ion, average dry deposition and canopy leaching were calculated. Leaching was the dominant process for TF enrichment by potassium. Leaching of base cations occurred during growing as well as dormant period. The calculated internal flux of Ca(2+) and Mg(2+) varied in the range of 0.6-2.0 and 0.6-1.2 kg ha(-1) per year in spruce and pine stands, respectively. The internal circulation of K(+) was significantly higher (8.9-10.9 kg ha(-1) per year) in spruce stands than in pine stands (2.7-4.4 kg ha(-1) per year).

  9. Chesapeake Bay atmospheric deposition study. Phase 1. Final report, July 1990-June 1991

    SciTech Connect

    Baker, J.E.; Church, T.M.; Ondov, J.M.; Scudlark, J.R.; Conko, K.M.

    1992-12-01

    The purpose of the study was to determine atmospheric loadings of selected trace elements and organic compounds directly into the Chesapeake Bay. The work represents the first year of the Chesapeake Bay Atmospheric Deposition Study. A one-year study (6/90-7/91) was conducted to estimate the deposition of atmospheric contaminants to the Maryland portion of the Chesapeake Bay. The studied contaminants included the trace elements (Aluminum, Arsenic, Cadmium, Chromium, Copper, Iron, Manganese, Nickel, Lead, Selenium, and Zinc) polychlorinated biphenyl (PCBs) congeners, and polycyclic aromatic hydrocarbons (PAHs).

  10. Energy deposition in the earth's atmosphere due to impact of solar activity-generated disturbances

    NASA Technical Reports Server (NTRS)

    Wu, S. T.; Kan, L. C.; Tandberg-Hanssen, E.; Dryer, M.

    1979-01-01

    Energy deposition in and dynamic responses of the terrestrial atmosphere to solar flare-generated shocks and other physical processes - such as particle precipitation and local heating - are investigated self-consistently in the context of hydrodynamics, the problem being treated as an initial boundary-value problem. It is extremely difficult to construct a general model for the line solar activity-magnetosphere-atmosphere; however, a limited model for this link is possible. The paper describes such a model, and presents some results on energy deposition into the earth's atmosphere due to solar activity-generated disturbances. Results from the present calculations are presented and discussed.

  11. Contribution of atmospheric nitrate deposition to nitrate loading in the Chesapeake Bay. Final report

    SciTech Connect

    Tyler, M.

    1988-12-01

    Recent studies have suggested that nitrate introduced into the Chesapeake Bay via atmospheric deposition may be a significant source of excess nutrients. In order to determine if concerns about atmospheric deposition are justified, modeled estimates of wetfall nitrate deposition over the Chesapeake Bay basin, based on monitoring data collected in 1984, were used to estimate basin-wide nitrate loading (1.38 x 10/sup 8/ kg) over the land area of the basin. Estimates of transfer coefficients and nitrate loadings to the Bay for various land-use categories were also calculated, using figures developed by the EPA Chesapeake Bay Program. The conservative nature of assumptions made in developing these figures suggests that the actual percentage contribution of atmospheric nitrate deposition may be lower than the estimated value.

  12. Wet and Dry Atmospheric Mercury Deposition Accumulates in Watersheds of the Northeastern United States

    NASA Astrophysics Data System (ADS)

    Boyer, E. W.; Grant, C.; Grimm, J.; Drohan, P. J.; Bennett, J.; Lawler, D.

    2013-12-01

    Mercury emissions to the atmosphere from coal-fired power plants and other sources such as waste incineration can be deposited to landscapes in precipitation and in dry fallout. Some mercury reaches watersheds and streams, where it can accumulate in sediments and biota. Human exposure to mercury occurs primarily through fish consumption, and currently mercury fish eating advisories are in place for many of the streams and lakes in the state. Here, we explored mercury in air, soils, water, and biota. To quantify atmospheric mercury deposition, we measured both wet and dry mercury deposition at over 10 locations in Pennsylvania, from which we present variation in mercury deposition and initial assessments of factors affecting the patterns. Further, we simulated mercury deposition at unmonitored locations in Pennsylvania and the northeastern United States over space and time with a high-resolution modeling technique that reflects storm tracks and air flow patterns. To consider mercury accumulation in watersheds, we collected data on soil mercury concentrations in a set of soil samples, and collected baseline data on mercury in streams draining 35 forested watersheds across Pennsylvania, spanning gradients of atmospheric deposition, climate and geology. Mercury concentrations were measured in stream water under base-flow conditions, in streambed sediments, aquatic mosses, and in fish tissues from brook trout. Results indicate that wet and dry atmospheric deposition is a primary source of mercury that is accumulating in watersheds of Pennsylvania and the northeastern United States.

  13. Trends in the composition of wet deposition: effects of the atmospheric rehabilitation in East-Germany

    NASA Astrophysics Data System (ADS)

    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.

  14. Atmospheric nitrogen deposition in the Rocky Mountains of Colorado and southern Wyoming—a review and new analysis of past study results

    NASA Astrophysics Data System (ADS)

    Burns, Douglas A.

    The Rocky Mountain region of Colorado and southern Wyoming receives as much as 7 kg ha -1 yr -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 (> 3000 m) sites east of the Continental Divide in the Front Range. Much of this increase is the result of increased ammonium (NH 4+) 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 NH 4+ 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 0.013 kg ha -1 yr -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.

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

    USGS Publications Warehouse

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Nitrogen Deposition Effects on Diatom Communities in Lakes from Three National Parks in Washington State.

    PubMed

    Sheibley, Richard W; Enache, Mihaela; Swarzenski, Peter W; Moran, Patrick W; Foreman, James R

    2014-01-01

    The goal of this study was to document if lakes in National Parks in Washington have exceeded critical levels of nitrogen (N) deposition, as observed in other Western States. We measured atmospheric N deposition, lake water quality, and sediment diatoms at our study lakes. Water chemistry showed that our study lakes were ultra-oligotrophic with ammonia and nitrate concentrations often at or below detection limits with low specific conductance (<100 μS/cm), and acid neutralizing capacities (<400 μeq/L). Rates of summer bulk inorganic N deposition at all our sites ranged from 0.6 to 2.4 kg N ha(-1) year(-1) and were variable both within and across the parks. Diatom assemblages in a single sediment core from Hoh Lake (Olympic National Park) displayed a shift to increased relative abundances of Asterionella formosa and Fragilaria tenera beginning in the 1969-1975 timeframe, whereas these species were not found at the remaining (nine) sites. These diatom species are known to be indicative of N enrichment and were used to determine an empirical critical load of N deposition, or threshold level, where changes in diatom communities were observed at Hoh Lake. However, N deposition at the remaining nine lakes does not seem to exceed a critical load at this time. At Milk Lake, also in Olympic National Park, there was some evidence that climate change might be altering diatom communities, but more research is needed to confirm this. We used modeled precipitation for Hoh Lake and annual inorganic N concentrations from a nearby National Atmospheric Deposition Program station, to calculate elevation-corrected N deposition for 1980-2009 at Hoh Lake. An exponential fit to this data was hindcasted to the 1969-1975 time period, and we estimate a critical load of 1.0 to 1.2 kg N ha(-1) year(-1) for wet deposition for this lake. PMID:24578586

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed Central

    Li, Yunzhao; Du, Siyao; Han, Guangxuan; Xing, Qinghui; Wu, Huifeng; Wang, Guangmei

    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 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. PMID:24977238

  1. Current and historical deposition of PBDEs, pesticides, PCBs, and PAHs to Rocky Mountain National Park.

    PubMed

    Usenko, Sascha; Landers, Dixon H; Appleby, Peter G; Simonich, Staci L

    2007-11-01

    An analytical method was developed for the trace analysis of 98 semivolatile organic compounds (SOCs) in remote, high-elevation lake sediment. Sediment cores from Lone Pine Lake (west of the Continental Divide) and Mills Lake (east of the Continental Divide) in Rocky Mountain National Park, CO, were dated using 210Pb and 137Cs and analyzed for polybrominated diphenyl ethers (PBDEs), organochlorine pesticides, phosphorothioate pesticides, thiocarbamate pesticides, amide herbicides, triazine herbicides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) using this method. SOC deposition profiles were reconstructed, and deposition half-lives and doubling times were calculated, for U.S. historic-use pesticides (HUPs) and current-use pesticides (CUPs) as well as PBDEs, PCBs, and PAHs. Sediment records indicate that the deposition of CUPs has increased in recent years, while the deposition of HUPs has decreased since U.S. restriction, but has not been eliminated. This is likely due to the revolatilization of HUPs from regional soils, atmospheric transport, and deposition. Differences in the magnitude of SOC sediment fluxes, flux profiles, time trends within those profiles, and isomeric ratios suggest that SOC deposition in high-elevation ecosystems is dependent on regional upslope wind directions and site location with respect to regional sources and topographic barriers. PMID:18044494

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Global Simulation of Atmospheric Mercury Concentrations and Deposition Fluxes. Appendix Q

    NASA Technical Reports Server (NTRS)

    Shia, Run-Lie; Seigneur, Christian; Pai, Prasad; Ko, Malcolm; Sze, Nien Dak

    1999-01-01

    Results from a numerical model of the global emissions, transport, chemistry, and deposition of mercury (Hg) in the atmosphere are presented. Hg (in the form of Hg(O) and Hg(II)) is emitted into the atmosphere from natural and anthropogenic sources (estimated to be 4000 and 2100 Mg/ yr, respectively). It is distributed between gaseous, aqueous and particulate phases. Removal of Hg from the atmosphere occurs via dry deposition and wet deposition, which are calculated by the model to be 3300 and 2800 Mg/ yr, respectively. Deposition on land surfaces accounts for 47% of total global deposition. The simulated Hg ambient surface concentrations and deposition fluxes to the Earth's surface are consistent with available observations. Observed spatial and seasonal trends are reproduced by the model, although larger spatial variations are observed in Hg(O) surface concentrations than are predicted by the model. The calculated atmospheric residence time of Hg is -1.7 years. Chemical transformations between Hg(O) and HG(II) have a strong influence on Hg deposition patterns because HG(II) is removed faster than Hg(O). Oxidation of Hg(O) to HG(II) occurs primarily in the gas phase, whereas HG(II) reduction to Hg(O) occurs solely in the aqueous phase. Our model results indicated that in the absence of the aqueous reactions the atmospheric residence time of Hg is reduced to 1.2 from 1.7 years and the Hg surface concentration is -25% lower because of the absence of the HG(II) reduction pathway. This result suggests that aqueous chemistry is an essential component of the atmospheric cycling of Hg.

  4. Wet atmospheric deposition of pesticides in Minnesota, 1989-94

    USGS Publications Warehouse

    Capel, Paul D.; Lin, Ma; Wotzka, Paul J.

    1998-01-01

    The pesticide fluxes in the streams out of the small three watersheds was compared to the pesticide flux into the watersheds in rain. The data indicate that flux into the watersheds from the rain is generally much greater than the flux from the watersheds in the streams. Therefore, a large fraction of the pesticides deposited in rain is retained within the watersheds. For the urban area, this is on the order of 98 percent for the four most commonly observed herbicides in rain and runoff.

  5. Atmospheric Nitrogen Deposition: An increasingly Important Source of "new" Nitrogen Supporting Coastal Eutrophication

    NASA Astrophysics Data System (ADS)

    Paerl, H. W.; Whitall, D. R.; Dennis, R. L.

    2004-12-01

    Atmospheric deposition of nitrogen (AD-N) to the North Atlantic Ocean (NAO) basin arises from diverse pollution sources in North America and Western Europe; these sources have increased by 5 to10 fold since the Industrial Revolution, agricultural expansion and urbanization in the NAO airshed and continue to increase in both geographic and depositional magnitudes. Based on recent estimates, AD-N flux (11.2 Tg N per year) accounts for 46-57 per cent of the total new or externally-supplied anthropogenic N flux to the NAO. In US estuarine and coastal waters, from 10 to over 40 per cent of new N loading is attributed to AD-N; estimates for North Carolina's Albemarle-Pamlico Sound system range from 20 to over 30 per cent. In developing regions of the world, AD-N is one of the most rapidly expanding sources of new N. AD-N has been linked to eutrophication in N-sensitive coastal waters. In North Carolina, N deposition has increased since the 1960's as a result of urbanization (chiefly NOx) and more recently agricultural growth (NH4+ and organic N). In particular, rapidly-expanding livestock operations have led to increases in the generation of N-enriched wastes and manures; a substantial proportion (30- >70 per cent) of which may be emitted as NH3 gas. Recent growth and intensification of animal operations in the midwest and coastal regions (e.g., Mid-Atlantic coastal plain) have been linked to increasing amounts of NH4+ deposition, according to a 2 decadal analysis of the National Acid Deposition Program (NADP) network. The impacts of both increasing amounts and altered chemical composition of AD-N are being examined in the N-limited, eutrophying (i.e., expanding algal blooms, hypoxia and anoxia) Neuse River Estuary, Pamlico Sound and coastal waters of North Carolina. Because of its relatively large contribution to total new N loading and potential biogeochemical and ecological importance in N sensitive waters, AD-N requires attention from air/watershed nutrient budgeting

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

    NASA Astrophysics Data System (ADS)

    Makowski Giannoni, S.; Rollenbeck, R.; Trachte, K.; Bendix, J.

    2014-10-01

    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 been roughly identified in only a few lowland tropical forests. Even scarcer are studies of this type in tropical mountain forests, many of them mega-diversity hotspots and especially vulnerable to acidic deposition. In these places, the topographic complexity and related streamflow conditions affect 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 source 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.

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

    NASA Astrophysics Data System (ADS)

    Makowski Giannoni, S.; Rollenbeck, R.; Trachte, K.; Bendix, J.

    2014-05-01

    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.

  8. AIRSHED DOMAINS FOR MODELING ATMOSPHERIC DEPOSITION OF OXIDIZED AND REDUCED NITROGEN TO THE NEUSE/PAMLICO SYSTEM OF NORTH CAROLINA

    EPA Science Inventory

    Atmospheric deposition is important to nutrient loadings to coastal estuaries. Atmospheric emissions of nitrogen travel hundreds of kilometers as they are removed via atmospheric deposition. Long-range transport from outside the Neuse/Pamlico system in North Carolina is an impo...

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Spatial and Temporal Trends in Atmospheric Deposition in the Pensacola Bay Watershed

    NASA Astrophysics Data System (ADS)

    Caffrey, J. M.; Landing, W. M.; Cleveland, S. D.; Gosnell, K. J.; Bagui, S.

    2009-12-01

    Event based atmospheric deposition of mercury, trace metals and major ions has been monitored in the Pensacola Bay (Florida) watershed over the last three years at three locations to evaluate the temporal and spatial patterns in atmospheric wet deposition. A goal of this project is to evaluate the contribution of local sources (coal fired power plant and paper mill) to atmospheric deposition of mercury. There were no significant differences in the rainfall mercury flux among the three Pensacola Bay sites or between these sites and nearby Mercury Deposition Network monitoring sites along the Gulf Coast. Mercury deposition during the summer months is higher than other months due to higher concentrations in rainfall throughout the region. Correlation of mercury with other elements and major ions suggest that coal combustion is a significant source of mercury to the region, and may account for between 25 and 54% of the mercury deposited. Deposition of constituents like H+, sulfate, nitrate, ammonium, chloride and sodium, are much higher in Pensacola Bay that at NADP sites. Chloride and sodium fluxes are higher because Pensacola Bay sites are closer to the Gulf of Mexico which is a source of sea salt aerosols. Acid rain constituents, H+, sulfate, nitrate and ammonium are most likely higher at Pensacola Bay sites than NADP sites because Pensacola Bay sites are much closer to emission sources of these constituents, particularly the two Florida NADP sites FL14 and FL23 which are located in rural counties far from major industrial activities.

  11. Atmospheric Mercury Transfer to Peat Bogs Dominated by Gaseous Elemental Mercury Dry Deposition.

    PubMed

    Enrico, Maxime; Roux, Gaël Le; Marusczak, Nicolas; Heimbürger, Lars-Eric; Claustres, Adrien; Fu, Xuewu; Sun, Ruoyu; Sonke, Jeroen E

    2016-03-01

    Gaseous elemental mercury (GEM) is the dominant form of mercury in the atmosphere. Its conversion into oxidized gaseous and particulate forms is thought to drive atmospheric mercury wet deposition to terrestrial and aquatic ecosystems, where it can be subsequently transformed into toxic methylmercury. The contribution of mercury dry deposition is however largely unconstrained. Here we examine mercury mass balance and mercury stable isotope composition in a peat bog ecosystem. We find that isotope signatures of living sphagnum moss (Δ(199)Hg = -0.11 ± 0.09‰, Δ(200)Hg = 0.03 ± 0.02‰, 1σ) and recently accumulated peat (Δ(199)Hg = -0.22 ± 0.06‰, Δ(200)Hg = 0.00 ± 0.04‰, 1σ) are characteristic of GEM (Δ(199)Hg = -0.17 ± 0.07‰, Δ(200)Hg = -0.05 ± 0.02‰, 1σ), and differs from wet deposition (Δ(199)Hg = 0.73 ± 0.15‰, Δ(200)Hg = 0.21 ± 0.04‰, 1σ). Sphagnum covered during three years by transparent and opaque surfaces, which eliminate wet deposition, continue to accumulate Hg. Sphagnum Hg isotope signatures indicate accumulation to take place by GEM dry deposition, and indicate little photochemical re-emission. We estimate that atmospheric mercury deposition to the peat bog surface is dominated by GEM dry deposition (79%) rather than wet deposition (21%). Consequently, peat deposits are potential records of past atmospheric GEM concentrations and isotopic composition.

  12. Atmospheric Mercury Transfer to Peat Bogs Dominated by Gaseous Elemental Mercury Dry Deposition.

    PubMed

    Enrico, Maxime; Roux, Gaël Le; Marusczak, Nicolas; Heimbürger, Lars-Eric; Claustres, Adrien; Fu, Xuewu; Sun, Ruoyu; Sonke, Jeroen E

    2016-03-01

    Gaseous elemental mercury (GEM) is the dominant form of mercury in the atmosphere. Its conversion into oxidized gaseous and particulate forms is thought to drive atmospheric mercury wet deposition to terrestrial and aquatic ecosystems, where it can be subsequently transformed into toxic methylmercury. The contribution of mercury dry deposition is however largely unconstrained. Here we examine mercury mass balance and mercury stable isotope composition in a peat bog ecosystem. We find that isotope signatures of living sphagnum moss (Δ(199)Hg = -0.11 ± 0.09‰, Δ(200)Hg = 0.03 ± 0.02‰, 1σ) and recently accumulated peat (Δ(199)Hg = -0.22 ± 0.06‰, Δ(200)Hg = 0.00 ± 0.04‰, 1σ) are characteristic of GEM (Δ(199)Hg = -0.17 ± 0.07‰, Δ(200)Hg = -0.05 ± 0.02‰, 1σ), and differs from wet deposition (Δ(199)Hg = 0.73 ± 0.15‰, Δ(200)Hg = 0.21 ± 0.04‰, 1σ). Sphagnum covered during three years by transparent and opaque surfaces, which eliminate wet deposition, continue to accumulate Hg. Sphagnum Hg isotope signatures indicate accumulation to take place by GEM dry deposition, and indicate little photochemical re-emission. We estimate that atmospheric mercury deposition to the peat bog surface is dominated by GEM dry deposition (79%) rather than wet deposition (21%). Consequently, peat deposits are potential records of past atmospheric GEM concentrations and isotopic composition. PMID:26849121

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

    PubMed

    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.

  14. Atmospheric trace elements over source regions for Chinese dust: concentrations, sources and atmospheric deposition on the Loess plateau

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoye; Arimoto, Richard; An, Zhisheng; Chen, Tuo; Zhang, Guangyu; Zhu, Guanghua; Wang, Xinfu

    The mass-particle size distributions of up to 17 trace elements in aerosol particle samples from dust storm and non-dust storm periods were determined for three sites in or near the source regions of Chinese dust. The mass of particulate material in the atmosphere at the sites is dominated by mineral aerosol particles. An absolute principal component analysis of the non-dust storm elemental data for the loess region allows the estimation of the mass contributions from two coarse-particle classes (soil dust and dust associated with pollutants), and two fine-particle classes (soil dust and anomalously enriched). For most elements (Al, Si, Ca, Fe, Ti, K, S and As), the mass-particle size distributions (MSDs) were approximately log-normal. The mass-median diameters (MMDs) of the soil-derived elements tended to decrease with distance from the desert region and when the dust storms subsided. Total dry deposition velocities were calculated by fitting a log-normal distribution to the aerosol data and calculating deposition rates for 100 particle-size intervals using a two-layer deposition model. The mean dry-deposition rates and fluxes were highest during dust storms over desert regions. In thloess region, the calculated dry deposition velocities of soil derived elements (Al, Si, Ca, Fe and Ti) during non-dust storm periods were from 3.1 to 3.7 cm s -1. From the estimated mass-particles size distributions, the coarser and finer mineral particles were found to benriched with Ca, Fe, Ti and K relative to Al or Si. On a yearly basis, the dry atmospheric input to the Loess Plateau was mainly attributable to normal transport processes, i.e. non-dust storm conditions. Wet deposition fluxes estimated from scavenging ratios indicate that dry deposition dominated the total atmospheric deposition of mineral aerosol. The deposition of aerosol particles associated with coal burning or other anthropogenic sources also was considerable on the Loess Plateau.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. National Atmospheric Release Advisory Center (NARAC) Capabilities for Homeland Security

    SciTech Connect

    Sugiyama, G; Nasstrom, J; Baskett, R; Simpson, M

    2010-03-08

    The Department of Energy's National Atmospheric Release Advisory Center (NARAC) provides critical information during hazardous airborne releases as part of an integrated national preparedness and response strategy. Located at Lawrence Livermore National Laboratory, NARAC provides 24/7 tools and expert services to map the spread of hazardous material accidentally or intentionally released into the atmosphere. NARAC graphical products show affected areas and populations, potential casualties, and health effect or protective action guideline levels. LLNL experts produce quality-assured analyses based on field data to assist decision makers and responders. NARAC staff and collaborators conduct research and development into new science, tools, capabilities, and technologies in strategically important areas related to airborne transport and fate modeling and emergency response. This paper provides a brief overview of some of NARAC's activities, capabilities, and research and development.

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

    PubMed

    De Temmerman, L; Waegeneers, N; Ruttens, A; Vandermeiren, K

    2015-04-01

    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.

  18. Increasing N abundance in the northwestern Pacific Ocean due to atmospheric nitrogen deposition.

    PubMed

    Kim, Tae-Wook; Lee, Kitack; Najjar, Raymond G; Jeong, Hee-Dong; Jeong, Hae Jin

    2011-10-28

    The relative abundance of nitrate (N) over phosphorus (P) has increased over the period since 1980 in the marginal seas bordering the northwestern Pacific Ocean, located downstream of the populated and industrialized Asian continent. The increase in N availability within the study area was mainly driven by increasing N concentrations and was most likely due to deposition of pollutant nitrogen from atmospheric sources. Atmospheric nitrogen deposition had a high temporal correlation with N availability in the study area (r = 0.74 to 0.88), except in selected areas wherein riverine nitrogen load may be of equal importance. The increase in N availability caused by atmospheric deposition and riverine input has switched extensive parts of the study area from being N-limited to P-limited. PMID:21940860

  19. Tracing atmospheric nitrate deposition in a complex semiarid ecosystem using delta17O.

    PubMed

    Michalski, Greg; Meixner, Thomas; Fenn, Mark; Hernandez, Larry; Sirulnik, Abby; Allen, Edith; Thiemens, Mark

    2004-04-01

    The isotopic composition of nitrate collected from aerosols, fog, and precipitation was measured and found to have a large 17O anomaly with delta17O values ranging from 20 percent per thousand to 30% percent per thousand (delta17O = delta17O - 0.52(delta18O)). This 17O anomaly was used to trace atmospheric deposition of nitrate to a semiarid ecosystem in southern California. We demonstrate that the delta17O signal is a conserved tracer of atmospheric nitrate deposition and is a more robust indicator of N deposition relative to standard delta18O techniques. The data indicate that a substantial portion of nitrate found in the local soil, stream, and groundwater is of atmospheric origin and does not undergo biologic processing before being exported from the system.

  20. Recent trends in atmospheric deposition of trace elements in Norway as evident from the 1995 moss survey.

    PubMed

    Berg, T; Steinnes, E

    1997-12-22

    Atmospheric trace element deposition in Norway has been evaluated by using data from a national moss survey from 1995, comprising 53 elements in 458 samples of the ground growing moss Hylocomium splendens. The results are compared with similar surveys carried out in 1977, 1985 and 1990 in order to evaluate temporal deposition trends. Atmospheric long-range transport (LRTP) from other parts of Europe is the main source for deposition of V, Zn, As, Mo, Ag, Cd, Sn, Sb, Hg, Tl, Pb and Bi in Norway. Between 1977 and 1990 the levels of most of the LRTP elements monitored (V, Zn, As, Cd, Sb, Pb) were reduced by more than 50%. Between 1990 and 1995, no further decrease has been observed for any of the LRTP elements, except for Pb where a further reduction is evident. The most north-easterly part of Norway is exposed to high levels of Co, Ni and Cu from emission sources from the Kola peninsula, Russia and the levels have not changed significantly since 1977. A new ferro-chrome smelter at Mo i Rana, northern Norway has resulted in a substantially enhanced deposition of Cr in the surrounding area.

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

    PubMed

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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

  4. Assessment of the Altitudinal Atmospheric Metal(loid) Deposition in a Mountainous City by Mosses.

    PubMed

    Li, Haixia; Zhang, Guoping; Liu, Hong; Li, Ling; Fu, Zhiping; Ouyang, Xiaoxue; Chen, Jingjing; Hu, Jian

    2015-08-01

    Samples of moss (Haplocladium microphyllum) were collected at different elevations on a mountain and four representative sites in Guiyang City, and the concentrations of metal(loid)s were determined by ICP-MS. The altitudinal deposition of soil-originated metals differed from that of anthropogenic metal(loid)s. The concentrations of soil-related elements decreased with elevation, indicating that these elements tend to deposit at lower elevations and their impact on the higher elevations is less. The concentrations of anthropogenic elements varied only slightly with elevation, indicating that the atmospheric deposition of these elements did not vary largely with elevation. The results of this study showed that the mosses at different locations may serve to indicate a vertical gradient of atmospheric metal(loid) deposition. PMID:26055166

  5. Shifts in lake N: P stoichiometry and nutrient limitation driven by atmospheric nitrogen deposition

    USGS Publications Warehouse

    Elser, J.J.; Andersen, T.; Baron, J.S.; Bergstrom, A.-K.; Jansson, M.; Kyle, M.; Nydick, K.R.; Steger, L.; Hessen, D.O.

    2009-01-01

    Human activities have more than doubled the amount of nitrogen (N) circulating in the biosphere. One major pathway of this anthropogenic N input into ecosystems has been increased regional deposition from the atmosphere. Here we show that atmospheric N deposition increased the stoichiometric ratio of N and phosphorus (P) in lakes in Norway, Sweden, and Colorado, United States, and, as a result, patterns of ecological nutrient limitation were shifted. Under low N deposition, phytoplankton growth is generally N-limited; however, in high-N deposition lakes, phytoplankton growth is consistently P-limited. Continued anthropogenic amplification of the global N cycle will further alter ecological processes, such as biogeochemical cycling, trophic dynamics, and biological diversity, in the world's lakes, even in lakes far from direct human disturbance.

  6. Shifts in lake N:P stoichiometry and nutrient limitation driven by atmospheric nitrogen deposition.

    PubMed

    Elser, James J; Andersen, Tom; Baron, Jill S; Bergström, Ann-Kristin; Jansson, Mats; Kyle, Marcia; Nydick, Koren R; Steger, Laura; Hessen, Dag O

    2009-11-01

    Human activities have more than doubled the amount of nitrogen (N) circulating in the biosphere. One major pathway of this anthropogenic N input into ecosystems has been increased regional deposition from the atmosphere. Here we show that atmospheric N deposition increased the stoichiometric ratio of N and phosphorus (P) in lakes in Norway, Sweden, and Colorado, United States, and, as a result, patterns of ecological nutrient limitation were shifted. Under low N deposition, phytoplankton growth is generally N-limited; however, in high-N deposition lakes, phytoplankton growth is consistently P-limited. Continued anthropogenic amplification of the global N cycle will further alter ecological processes, such as biogeochemical cycling, trophic dynamics, and biological diversity, in the world's lakes, even in lakes far from direct human disturbance.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. The biogeochemistry of an ombrotrophic bog: Evaluation of use as an archive of atmospheric mercury deposition

    SciTech Connect

    Benoit, J.M.; Fitzgerald, W.F.; Damman, A.W.H.

    1998-08-01

    The utility of ombrotrophic bogs as archives of atmospheric mercury deposition was assessed with an investigation in Arlberg Bog, Minnesota, US. Since the use of ombrotrophic bogs as archives depends on the immobility of deposited trace metals, the authors examined the postdepositional transport processes revealed by the solid-phase distributions of mercury and ancillary metals in this bog. They modeled metal speciation in bog pore-waters as a function of pe in order to understand metal behavior in ombrotrophic peat. Specifically, they considered the effect of water movement and resultant shifts in redox potential gradients on metal retention. The results indicate that Hg and Pb are immobile in ombrotrophic peat, so their distribution can be used to determine temporal changes in deposition. To substantiate the deposition estimates determined in this study, they emphasized the importance of confirming the validity of the dating scheme, assessing the degree of horizontal homogeneity in the accumulation record, and providing evidence for retention of Hg based on geochemical modeling. As recorded in Arlberg Bog, historic atmospheric Hg deposition increased gradually after the mid-1800s, peaked between 1950 and 1960, and may have declined thereafter. Preindustrial deposition was about 4 {micro}g/m{sup 2} year and recent deposition about 19 {micro}g/m{sup 2} year. The results of this study indicate that deposition at Arlberg Bog has been influenced by a regional and/or local-scale source.

  9. Modelling the effect of atmospheric nitrogen deposition on marine phytoplankton in the Singapore Strait.

    PubMed

    Sundarambal, P; Tkalich, P; Balasubramanian, R

    2010-01-01

    Atmospheric deposition is an important source of nutrients to the ocean, potentially stimulating primary production, but its relative effect on coastal eutrophication remains largely unknown. This paper presents data generated by the 3-D modelling program NEUTRO to assess the proportion of atmospheric nutrient fluxes, allowing a quantification of the relative contribution of atmospheric and ocean fluxes in the Singapore Strait. This work included an assessment of the importance of high concentration episodic inputs of nitrate-nitrogen associated with transport of polluted air onto the surface water. The NEUTRO model features a nutrient-fuelled food web composed of nutrients, plankton, and dissolved oxygen dynamics. Model simulations show that atmospheric deposition fluxes alone might contribute nitrate-nitrogen mass up to 15% into the Singapore Strait. This amount might be a significant contributor toward regional eutrophication when the system is under nutrient-depleted conditions. Model calibrations for temporal and spatial variability of nutrients qualitatively and quantitatively agreed with available measurements.

  10. Uncertainty analysis of atmospheric deposition simulation of radiocesium and radioiodine from Fukushima Daiichi Nuclear Power Plant

    NASA Astrophysics Data System (ADS)

    Morino, Yu; Ohara, Toshimasa; Yumimoto, Keiya

    2014-05-01

    Chemical transport models (CTM) played key roles in understanding the atmospheric behaviors and deposition patterns of radioactive materials emitted from the Fukushima Daiichi nuclear power plant (FDNPP) after the nuclear accident that accompanied the great Tohoku earthquake and tsunami on 11 March 2011. In this study, we assessed uncertainties of atmospheric simulation by comparing observed and simulated deposition of radiocesium (137Cs) and radioiodine (131I). Airborne monitoring survey data were used to assess the model performance of 137Cs deposition patterns. We found that simulation using emissions estimated with a regional-scale (~500 km) CTM better reproduced the observed 137Cs deposition pattern in eastern Japan than simulation using emissions estimated with local-scale (~50 km) or global-scale CTM. In addition, we estimated the emission amount of 137Cs from FDNPP by combining a CTM, a priori source term, and observed deposition data. This is the first use of airborne survey data of 137Cs deposition (more than 16,000 data points) as the observational constraints in inverse modeling. The model simulation driven by a posteriori source term achieved better agreements with 137Cs depositions measured by aircraft survey and at in-situ stations over eastern Japan. Wet deposition module was also evaluated. Simulation using a process-based wet deposition module reproduced the observations well, whereas simulation using scavenging coefficients showed large uncertainties associated with empirical parameters. The best-available simulation reproduced the observed 137Cs deposition rates in high-deposition areas (≥10 kBq m-2) within one order of magnitude. Recently, 131I deposition map was released and helped to evaluate model performance of 131I deposition patterns. Observed 131I/137Cs deposition ratio is higher in areas southwest of FDNPP than northwest of FDNPP, and this behavior was roughly reproduced by a CTM if we assume that released 131I is more in gas phase

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

    USGS Publications Warehouse

    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 (<2 kg N??ha-1??yr-1) levels of 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.

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

    PubMed

    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.

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

    PubMed

    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

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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).

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

    NASA Astrophysics Data System (ADS)

    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.

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

    USGS Publications Warehouse

    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.

  18. Deuterium Retention in the Co-Deposition Carbon Layers Deposited by Radio-Frequency Magnetron Sputtering in D2 Atmosphere

    NASA Astrophysics Data System (ADS)

    Zhang, Wei-Yuan; Shi, Li-Qun; Zhang, Bin; Hu, Jian-Sheng

    2014-05-01

    Carbon is deposited on C and Si substrates by rf magnetron plasma sputtering in a D2 atmosphere. The deposited layers are examined with ion beam analysis and thermal desorption spectroscopy (TDS). The growth rates of the layers deposited on Si decrease with increasing substrate temperature, while increase significantly with the increase of D2 pressure. Meanwhile, the deuterium concentrations in the layers deposited on the Si substrates decrease from 30% to 2% and from 31% to 1% on the C substrates, respectively, when the substrate temperature varies from 350K to 900 K. Similarly, the D concentration in the layer on the Si substrates increases from 3.4% to 47%, and from 8% to 35% on the C substrates when the D2 pressure increases from 0.3Pa to 8.0Pa. D desorption characterized by TDS is mainly in the forms of D2, HD, HDO, CD4, and C2D4, and a similar release peak occurs at 645 K. The release peak of D2 molecules at 960K can be attributed to the escaped gas from the thin co-deposited deuterium-rich carbon layer in the form of C-D bonding.

  19. The Watershed Deposition Tool: A Tool for Incorporating Atmospheric Deposition in Watershed Analysis

    EPA Science Inventory

    The 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. The Watershed Deposition Tool (WDT) takes gridded output of at...

  20. Wet deposition of atmospheric inorganic nitrogen at five remote sites in the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Liu, Y. W.; Xu-Ri; Wang, Y. S.; Pan, Y. P.; Piao, S. L.

    2015-10-01

    Since the mid-20th century, nitrogen (N) deposition has shown an increasing trend in the Tibetan Plateau (TP), where alpine ecosystems are sensitive to elevated N deposition. However, the quantitative characterization of N deposition in the TP remains unclear, due in most part to the lack of in situ measurement. Using the Tibetan Observation and Research Platform network, we conducted short-term in situ measurements of major ions (NO3-, Cl-, SO42-, NH4+, Na+, K+, Ca2+, and Mg2+) wet deposition at five remote sites in the TP during 2011-2013. At Southeast Tibet Station, Nam Co Station, Qomolangma Station, Ngari Station, and Muztagh Ata Station, the NH4+-N wet deposition was 0.63, 0.68, 0.92, 0.36, and 1.25 kg N ha-1 yr-1, respectively; the NO3--N wet deposition was 0.28, 0.24, 0.03, 0.08, and 0.30 kg N ha-1 yr-1, respectively; and the inorganic N wet deposition was 0.91, 0.92, 0.94, 0.44, and 1.55 kg N ha-1 yr-1, respectively. The inorganic N wet deposition mainly occurred in the form of NH4+-N during summer at all sites. Results of enrichment factor analysis and principal component analysis demonstrated that both NH4+-N and NO3--N wet deposition in the TP were mainly influenced by anthropogenic activities. Backward trajectory analysis showed that the inorganic N deposition at Muztagh Ata Station was mainly transported from central Asia and the Middle East through westerlies. At Southeast Tibet Station, Nam Co Station, Qomolangma Station, and Ngari Station, the inorganic N deposition was mainly contributed by anthropogenic sources in south Asia, and was mainly transported by the Indian monsoon. Combining site-scale in situ measurements of inorganic N wet deposition in this and previous studies, the average wet deposition of atmospheric NH4+-N, NO3--N, and inorganic N in the TP was estimated to be 1.06, 0.51, and 1.58 kg N ha-1 yr-1, respectively. The average NH4+-N : NO3--N ratio in precipitation in the TP was approximately 2 : 1. Results from the present study

  1. Atmospheric deposition of nutrients to north Florida rivers: A multivariate statistical analysis. Final report. Master's thesis

    SciTech Connect

    Fu, J.

    1991-01-01

    Atmospheric nutrient input to the Apalachicola Bay estuary was studied because it has been demonstrated that atmospheric deposition can be a major source of nutrients to eastern U.S. estuaries. Besides the Apalachicola River, the Sopchoppy and the Ochlockonee were also selected for a comparative analysis. Receptor model, absolute principal of component analysis (APCA), and mass balance methods were applied in the study. The results of the study show that nitrogen is probably not a limiting nutrient in the three rivers because their N:P mole ratios are nearly 3 times higher than the Redfield ratio for photosynthesis. The total atmospheric nitrogen depositions in the three river watershed are at least as great as their river fluxes. In the Apalachicola River, the atmospheric source of nitrogen is found to be several times higher than the largest possible input of urban sewage. Atmospheric deposition, therefore, might be the dominant nitrogen source entering the estuary. The results of APCA show that Apalachicola River water is mainly a mixture of components that correspond in their compositions to aged rain, ground water, and fresh rain. Atmospheric nitrate deposition is the result of the air pollution, i.e., acid rain. The studies also show that the annual average deposition of nitrate has a narrow range, mainly from 5.8 to 11.5 kg/ha/yr in most of the NADP sites in the 8 southeastern states. Since all the software and data sets employed in the study are accessible nationwide, the methods could be applied in other watersheds.

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

    USGS Publications Warehouse

    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.

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

    PubMed Central

    Simkin, Samuel M.; Allen, Edith B.; Bowman, William D.; Clark, Christopher M.; Belnap, Jayne; Brooks, Matthew L.; Cade, Brian S.; 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. PMID:27035943

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

    PubMed

    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

    2016-04-12

    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. PMID:27035943

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

    NASA Astrophysics Data System (ADS)

    Giordano, Michael R.; Chong, Joey; Weise, David R.; Asa-Awuku, Akua A.

    2016-03-01

    Chronic nitrogen deposition has measureable impacts on soil and plant health. We investigate burning emissions from biomass grown in areas of high and low NO x 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 NO x deposition exhibit a lower volatility than biomass grown in a low deposition area. Furthermore, fuel elemental analysis, NO x 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.

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

    PubMed

    Liu, Xue-Yan; Xiao, Hua-Yun; Liu, Cong-Qiang; Li, You-Yi; Xiao, Hong-Wei; Wang, Yan-Li

    2010-06-01

    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 delta13C 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 delta13C(moss) became less negative. With measurements of atmospheric CO2 and delta13CO2, 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 delta13C(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.

  7. Inorganic nitrogenous air pollutants, atmospheric nitrogen deposition and their potential ecological impacts in remote areas of western North America (Invited)

    NASA Astrophysics Data System (ADS)

    Bytnerowicz, A.; Fenn, M. E.; Fraczek, W.; Johnson, R.; Allen, E. B.

    2013-12-01

    Dry deposition of gaseous inorganic nitrogenous (N) air pollutants plays an important role in total atmospheric N deposition and its ecological effects in the arid and semi-arid ecosystems. Passive samplers and denuder/ filter pack systems have been used for determining ambient concentrations of ammonia (NH3), nitric oxide (NO), nitrogen dioxide (NO2), and nitric acid vapor (HNO3) in the topographically complex remote areas of the western United States and Canada. Concentrations of the measured pollutants varied significantly between the monitoring areas. Highest NH3, NO2 and HNO3 levels occurred in southern California areas downwind of the Los Angeles Basin and in the western Sierra Nevada impacted by emissions from the California Central Valley and the San Francisco Bay area. Strong spatial gradients of N pollutants were also present in southeastern Alaska due to cruise ship emissions and in the Athabasca Oil Sands Region in Canada affected by oil exploitation. Distribution of these pollutants has been depicted by maps generated by several geostatistical methodologies within the ArcGIS Geostatistical Analyst (ESRI, USA). Such maps help to understand spatial and temporal changes of air pollutants caused by various anthropogenic activities and locally-generated vs. long range-transported air pollutants. Pollution distribution maps for individual N species and gaseous inorganic reactive nitrogen (Nr) have been developed for the southern portion of the Sierra Nevada, Lake Tahoe Basin, San Bernardino Mountains, Joshua Tree National Park and the Athabasca Oil Sands Region. The N air pollution data have been utilized for estimates of dry and total N deposition by a GIS-based inferential method specifically developed for understanding potential ecological impacts in arid and semi-arid areas. The method is based on spatial and temporal distribution of concentrations of major drivers of N dry deposition, their surface deposition velocities and stomatal conductance values

  8. Is it possible to estimate atmospheric deposition of heavy metals by analysis of terrestrial mosses?

    PubMed

    Aboal, J R; Fernández, J A; Boquete, T; Carballeira, A

    2010-11-15

    Here we present a critical review of diverse research studies involving estimation of atmospheric deposition of heavy metals from the concentrations of the contaminants in terrestrial moss. The findings can be summarized as follows: i) significant correlations between the concentrations of contaminants in moss and bulk deposition were observed in only 40.1% of the cases in which the relationship was studied and in only 14.1% of the cases, the coefficient of correlation was >0.7; ii) some method-related problems were identified (i.e. small sample sizes, elimination of some data from the regression analyses, large distances between the moss sampling sites and the bulk precipitation collectors, differences in times of exposure of the moss samples and collection times for the bulk precipitation), so that the results of the studies may not be completely valid, and iii) evidence was found in the relevant literature that moss does not actually integrate the atmospheric deposition received. We also discuss the reason why, in accordance with the published data, bulk deposition cannot be correctly estimated by determination of the final concentrations of contaminants in the organism, such as the existence of different sources of contamination, the physicochemical characteristics of the sources of deposition, physicochemical processes to which the organism is subjected and the biological processes that take place in the moss. Taking into account the above findings, it was concluded that, except for certain elements and specific cases (i.e. Pb and Cd), atmospheric deposition of elements cannot be accurately estimated from the concentrations of metals and metalloids in moss tissues. However, the analysis of moss does provide information about the presence of contaminants in the atmosphere, their spatial and temporal patterns of distribution and how they are taken up by live organisms. Use of mosses is therefore recommended as a complementary (rather than an alternative

  9. Eutrophication trends in forest soils in Galicia (NW Spain) caused by the atmospheric deposition of nitrogen compounds.

    PubMed

    Rodríguez, Luis; Macías, Felipe

    2006-06-01

    We calculated the sensitivity of Galician forest soils to eutrophication caused by atmospheric deposition of nitrogen compounds, using the Simple Mass Balance (SMB) method as described by [Posch, M., de Vries, W., Hettelingh, J.-P., 1995. Critical loads of sulphur and nitrogen. In: Posch, M., de Smet, P.A.M., Hettelingh, J.-P., Downing, R.J. Calculation and Mapping of Critical Thresholds in Europe. Status Report 1995, Coordination Center for Effects, National Institute for Public Health and the Environment, Bilthoven, The Netherlands, pp. 31-42]. Deposition values were used to calculate critical loads exceedance. Galician natural forest ecosystems can support nitrogen deposition loads of more than 10 kg Nha (-1) yr (-1). The lowest critical loads (approximately 10 kg Nha (-1) yr (-1)) mainly occurred in forest stands in the interior zone, while highest critical load values (approximately 68 kg Nha (-1) yr (-1)) were observed in eucalyptus stands at low altitudes in the littoral area. Exceedances based on N deposition levels, calculated from data recorded in 2001, occurred in 40% of the forest soils, showing the need to control N emissions in these areas to prevent possible eutrophication of soils and waters. Analysis of rainfall bulk composition revealed that ammonium, probably derived from agricultural and cattle activities, was the main compound responsible for N deposition in Galicia.

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

    NASA Astrophysics Data System (ADS)

    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).

  11. Linking atmospheric composition data across data types and national boundaries

    NASA Astrophysics Data System (ADS)

    Schultz, Martin; Lyapina, Olga; Schröder, Sabine; Stein, Olaf; Mallmann, Daniel

    2016-04-01

    The field of atmospheric composition research involves the management of data sources from various disciplines such as meteorology, chemistry, (radiation) physics, emission inventories, etc. The output from global and regional chemistry climate models, chemistry transport models, and air quality models presents considerable challenges due to the manifold variables of interest and the multitude of diagnostics needed in order to interpret the results. Furthermore, many observations of atmospheric composition exist from different platforms involving different geometries, time resolutions, size spectra, etc. Due to the fact that few observation networks are globally coordinated, various representations of data formats and metadata definitions exist. For example, there is no unique agreement on chemical species names and in many networks, national languages are used to document the data. We will present a summary of the issues involving global interoperability of atmospheric composition data including the aspects of data volume, data compexity and metadata standardisation, and we will demonstrate various activities carried out in Jülich and internationally to overcome these challenges. Specifically, we will describe the current implementation and plans for the Copernicus Atmosphere Monitoring Service boundary condition service (http://ows-server.iek.fz-juelich.de), the design of the JOIN web interface (https://join.fz-juelich.de), and the activities for building an ontology of atmospheric composition vocabulary (https://ontology.geodab.eu/).

  12. ATMOSPHERIC MERCURY DEPOSITION TO LAKE MICHIGAN DURING THE LAKE MICHIGAN MASS BALANCE STUDY

    EPA Science Inventory

    Wet and dry mercury (Hg) deposition were calculated to Lake Michigan using a hybrid receptor modeling framework. The model utilized mercury monitoring data collected during the Lake Michigan Mass Balance Study and the Atmospheric Exchange Over Lakes and Oceans Study together w...

  13. Deposition and accumulation of airborne organic contaminants in Yosemite National Park, Calfornia

    USGS Publications Warehouse

    Mast, Alisa M.; Alvarez, David A.; Zaugg, Steven D.

    2012-01-01

    Deposition and accumulation of airborne organic contaminants in Yosemite National Park were examined by sampling atmospheric deposition, lichen, zooplankton, and lake sediment at different elevations. Passive samplers were deployed in high-elevation lakes to estimate surface-water concentrations. Detected compounds included current-use pesticides chlorpyrifos, dacthal, and endosulfans and legacy compounds chlordane, dichlorodiphenyltrichloroethane-related compounds, dieldrin, hexachlorobenzene, and polychlorinated biphenyls. Concentrations in snow were similar among sites and showed little variation with elevation. Endosulfan concentrations in summer rain appeared to coincide with application rates in the San Joaquin Valley. More than 70% of annual pesticide inputs from atmospheric deposition occurred during the winter, largely because most precipitation falls as snow. Endosulfan and chlordane concentrations in lichen increased with elevation, indicating that mountain cold-trapping might be an important control on accumulation of these compounds. By contrast, chlorpyrifos concentrations were inversely correlated with elevation, indicating that distance from source areas was the dominant control. Sediment concentrations were inversely correlated with elevation, possibly because of the organic carbon content of sediments but also perhaps the greater mobility of organic contaminants at lower elevations. Surface-water concentrations inferred from passive samplers were at sub-parts-per-trillion concentrations, indicating minimal exposure to aquatic organisms from the water column. Concentrations in sediment generally were low, except for dichlorodiphenyldichloroethane in Tenaya Lake, which exceeded sediment guidelines for protection of benthic organisms.

  14. Deposition and accumulation of airborne organic contaminants in Yosemite National Park, California.

    PubMed

    Mast, M Alisa; Alvarez, David A; Zaugg, Steven D

    2012-03-01

    Deposition and accumulation of airborne organic contaminants in Yosemite National Park were examined by sampling atmospheric deposition, lichen, zooplankton, and lake sediment at different elevations. Passive samplers were deployed in high-elevation lakes to estimate surface-water concentrations. Detected compounds included current-use pesticides chlorpyrifos, dacthal, and endosulfans and legacy compounds chlordane, dichlorodiphenyltrichloroethane-related compounds, dieldrin, hexachlorobenzene, and polychlorinated biphenyls. Concentrations in snow were similar among sites and showed little variation with elevation. Endosulfan concentrations in summer rain appeared to coincide with application rates in the San Joaquin Valley. More than 70% of annual pesticide inputs from atmospheric deposition occurred during the winter, largely because most precipitation falls as snow. Endosulfan and chlordane concentrations in lichen increased with elevation, indicating that mountain cold-trapping might be an important control on accumulation of these compounds. By contrast, chlorpyrifos concentrations were inversely correlated with elevation, indicating that distance from source areas was the dominant control. Sediment concentrations were inversely correlated with elevation, possibly because of the organic carbon content of sediments but also perhaps the greater mobility of organic contaminants at lower elevations. Surface-water concentrations inferred from passive samplers were at sub-parts-per-trillion concentrations, indicating minimal exposure to aquatic organisms from the water column. Concentrations in sediment generally were low, except for dichlorodiphenyldichloroethane in Tenaya Lake, which exceeded sediment guidelines for protection of benthic organisms.

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

    PubMed

    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

  16. Atmospheric trace elements at Enewetak Atoll: 2. Transport to the ocean by wet and dry deposition

    NASA Astrophysics Data System (ADS)

    Arimoto, R.; Duce, R. A.; Ray, B. J.; Unni, C. K.

    1985-02-01

    The concentrations of trace elements in precipitation and dry deposition are presented for samples collected at Enewetak Atoll (11°N, 162° E) during SEAREX experiments in 1979. The concentrations of Al, Sc, Mn, Fe, Co, and Th in rain are dominated by crustal material, and for these elements, wet deposition evidently exceeds dry deposition. For most of these elements the present rates of atmospheric deposition at Enewetak are similar to their mean rate of accumulation in sediments over the past 5-10,000 years, suggesting that the air-to-sea exchange of particles is closely tied to the sedimentary cycle of the mid-Pacific. Noncrustal sources govern the concentrations of Pb, Zn, Cu, Se, and Cd in wet and dry deposition samples. Analyses of dry deposition collected from a flat plastic plate indicate that the amount of material recycled from the sea surface varies markedly between samples, and even though these estimates do not necessarily reflect the dry deposition to the ocean surface, the results suggest that recycled sea spray often amounts to more than 50% of the total dry deposition of the enriched elements. Recycled sea spray also makes up a significant fraction of the total wet deposition of the enriched elements. The net deposition rates of elements such as Cu and Zn are greater than or equal to their inputs from vertical mixing, but the net deposition of Pb clearly exceeds the input from upwelling. The current net deposition rates of the enriched elements are also similar to their rates of removal to sediments. These results indicate that air-sea exchange processes may significantly affect the chemistry of trace metals in the open ocean.

  17. 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

    NASA Astrophysics Data System (ADS)

    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.

  18. Chesapeake Bay atmospheric deposition study phase 2: July 1990-December 1991. Final report

    SciTech Connect

    Baker, J.E.; Burdige, D.; Church, T.M.; Cutter, G.; Dickhut, R.M.

    1994-07-01

    The purpose of the study was to determine atmospheric loadings of selected trace elements and organic compounds directly to the surface waters of the Chesapeake Bay. The work in this report represents the first eighteen months of the Chesapeake Bay Atmospheric Deposition Study. Future reports will describe the integrate results from the CBADS network through September 1993. An 18 month field study (6/90 - 12/91), conducted to estimate the deposition of atmospheric trace contaminants to the Chesapeake Bay, represents Phase II of the Chesapeake Bay Atmospheric Deposition Study (CBADS). Previously reported data from Phase I (6/90 - 7/91) is presented here in concert with data from 7/91 - 12/91. The trace elements (aluminum, arsenic, cadmium, chromium, copper, iron, manganese, nickel, lead, selenium, and zinc), polychlorinated biphenyl (PCBs) congeners, and polycyclic aromatic hydrocarbons (PAHs) were measured in the ambient atmosphere and in precipitation. In addition several major ions, (chloride, sulfate, nitrate, sodium) were measured in precipitation at the three sites.

  19. High Elevation Lakes of the Western US: Are we Studying Systems Recovering from Excess Atmospheric Deposition of Acids and Nutrients?

    NASA Astrophysics Data System (ADS)

    Sickman, J. O.

    2011-12-01

    Instrumental records and monitoring of high elevation lakes began in most areas of the western US in the early 1980s. Much effort has been devoted to detecting changes in these aquatic ecosystems resulting from increased atmospheric deposition of acids and nutrients. However, there is growing evidence that thresholds for atmospheric pollutants were crossed much earlier in the 20th Century and that some of the subsequent hydrochemical and ecological changes observed in these lakes may be the result of recovery from earlier atmospheric forcing. We examine responses of high elevation lakes to atmospheric deposition on annual to century timescales using data from a 29-year study of Emerald Lake (Sequoia National Park) and paleolimnological analyses of other high elevation lakes incorporating diatom species analyses and geochemical proxies for fossil-fuel burning. At Emerald Lake, we have observed multiple transitions between nitrogen and phosphorus limitation of phytoplankton, the earliest of which occurred in the beginning of the 1980s and may be the result of reduction in N deposition due to the Clean Air Act. Critical loads analyses incorporating diatom species in lake sediments suggest that thresholds for N deposition were crossed in the period of 1950-1980 in the Rocky Mountains and likely much earlier, 1900-1920, in the Sierra Nevada. Diatom species composition is strongly controlled by acid neutralizing capacity (ANC) in the Sierra Nevada and we have observed a pronounced decline and recovery of ANC over the period of 1920-1980 in some Sierra Nevada lakes that coincides with the abundance of spheroidal carbonaceous particles (i.e., a diagnostic tracer of fossil fuel combustion) preserved in lake sediments; these patterns appear to be driven by increased emissions of oxidized N and S in the mid-20th Century and reductions in acid precursor levels caused by the Clean Air Act in the 1970s. Thus, when interpreting observational records from western high elevation

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

    NASA Astrophysics Data System (ADS)

    Baker, Alex; Altieri, Katye; Okin, Greg; Dentener, Frank; Uematsu, Mitsuo; Kanakidou, Maria; Sarin, Manmohan; Duce, Robert; Galloway, Jim; Keene, Bill; Singh, Arvind; Zamora, Lauren; Lamarque, Jean-Francois; Hsu, Shih-Chieh

    2014-05-01

    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). The Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) recently completed a multi-model analysis of global N deposition, including comparisons to wet deposition observations from three regional networks in North America, Europe and Southeast Asia (Lamarque et al., Atmos. Chem. Phys., 13, 7977-8018, 2013). 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 very difficult. In this work we attempt instead to use ~2600 observations of aerosol nitrate and ammonium concentrations, acquired chiefly from sampling aboard ships in the period 1995 - 2012, to assess the ACCMIP N deposition fields over the remote ocean. This database is non-uniformly distributed in time and space. We selected four ocean regions (the eastern North Atlantic, the South 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. Two of these regions are adjacent to the land networks used in the ACCMIP

  1. Geochemical, isotopic, and mineralogical constraints on atmospheric deposition in the hyper-arid Atacama Desert, Chile

    NASA Astrophysics Data System (ADS)

    Wang, Fan; Michalski, Greg; Seo, Ji-hye; Ge, Wensheng

    2014-06-01

    Modern atmospheric deposition across the Atacama was collected by an array of dust traps that stretched from the Pacific coast to the Andean altiplano, and the material was analyzed for its geochemical, mass and isotopic composition. The coastal trap had the second-highest insoluble mineral particle and highest soluble salt deposition rates due to significant inputs from the Morro Mejillones Range and the Pacific Ocean, respectively. The Andean trap had the highest insoluble mineral particle deposition owing to transport of weathered material, but the lowest deposition rate of soluble salts due to its distance from the ocean and anthropogenic sources. The removal of oceanic material was effective by the coastal mountains, while the westward transport of the Andean material was determined to be minimal. The atmospheric deposition in the inland traps was mainly from the local entrainment of surface material, inland anthropogenic emissions, and transport of marine aerosols. The nitrate isotopes (δ15N and Δ17O) suggested that NOx sources and NO3- chemistry shifted along the west-east transect, and were greatly impacted by anthropogenic emissions with soil NO3- being a minor source of deposited nitrogen.

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

    PubMed

    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

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

    PubMed

    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.

  4. Ahead of his time: Jacob Lipman's 1930 estimate of atmospheric sulfur deposition for the conterminous United States

    USGS Publications Warehouse

    Landa, Edward R.; Shanley, James B.

    2015-01-01

    A 1936 New Jersey Agricultural Experiment Station Bulletin provided an early quantitative assessment of atmospheric deposition of sulfur for the United States that has been compared in this study with more recent assessments. In the early 20th century, anthropogenic sulfur additions from the atmosphere to the soil by the combustion of fossil fuels were viewed as part of the requisite nutrient supply of crops. Jacob G. Lipman, the founding editor of Soil Science, and his team at Rutgers University, made an inventory of such additions to soils of the conterminous United States during the economic depression of the 1930s as part of a federally funded project looking at nutrient balances in soils. Lipman's team gathered data compiled by the US Bureau of Mines on coal and other fuel consumption by state and calculated the corresponding amounts of sulfur emitted. Their work pioneered a method of assessment that became the norm in the 1970s to 1980s—when acid rain emerged as a national issue. Lipman's estimate of atmospheric sulfur deposition in the 1930 is in reasonable agreement with recent historic reconstructions.

  5. Response of lake chemistry to changes in atmospheric deposition and climate in three high-elevation wilderness areas of Colorado

    USGS Publications Warehouse

    Mast, M. Alisa; Turk, John T.; Clow, David W.; Campbell, Donald D.

    2011-01-01

    Trends in precipitation chemistry and hydrologic and climatic data were examined as drivers of long-term changes in the chemical composition of high-elevation lakes in three wilderness areas in Colorado during 1985-2008. Sulfate concentrations in precipitation decreased at a rate of -0.15 to -0.55 μeq/l/year at 10 high-elevation National Atmospheric Deposition Program stations in the state during 1987-2008 reflecting regional reductions in SO2 emissions. In lakes where sulfate is primarily derived from atmospheric inputs, sulfate concentrations also decreased although the rates generally were less, ranging from -0.12 to -0.27 μeq/l/year. The similarity in timing and sulfur isotopic data support the hypothesis that decreases in atmospheric deposition are driving the response of high-elevation lakes in some areas of the state. By contrast, in lakes where sulfate is derived primarily from watershed weathering sources, sulfate concentrations showed sharp increases during 1985-2008. Analysis of long-term climate records indicates that annual air temperatures have increased between 0.45 and 0.93°C per decade throughout most mountainous areas of Colorado, suggesting climate as a factor. Isotopic data reveal that sulfate in these lakes is largely derived from pyrite, which may indicate climate warming is preferentially affecting the rate of pyrite weathering.

  6. Response of lake chemistry to changes in atmospheric deposition and climate in three high-elevation wilderness areas of Colorado

    USGS Publications Warehouse

    Mast, M.A.; Turk, J.T.; Clow, D.W.; Campbell, D.H.

    2011-01-01

    Trends in precipitation chemistry and hydrologic and climatic data were examined as drivers of long-term changes in the chemical composition of high-elevation lakes in three wilderness areas in Colorado during 1985-2008. Sulfate concentrations in precipitation decreased at a rate of -0.15 to -0.55 ??eq/l/year at 10 high-elevation National Atmospheric Deposition Program stations in the state during 1987-2008 reflecting regional reductions in SO2 emissions. In lakes where sulfate is primarily derived from atmospheric inputs, sulfate concentrations also decreased although the rates generally were less, ranging from -0.12 to -0.27 ??eq/l/year. The similarity in timing and sulfur isotopic data support the hypothesis that decreases in atmospheric deposition are driving the response of high-elevation lakes in some areas of the state. By contrast, in lakes where sulfate is derived primarily from watershed weathering sources, sulfate concentrations showed sharp increases during 1985-2008. Analysis of long-term climate records indicates that annual air temperatures have increased between 0.45 and 0.93??C per decade throughout most mountainous areas of Colorado, suggesting climate as a factor. Isotopic data reveal that sulfate in these lakes is largely derived from pyrite, which may indicate climate warming is preferentially affecting the rate of pyrite weathering. ?? 2010 US Government.

  7. Monitoring atmospheric levels and deposition of dioxin-like pollutants in sub-alpine Northern Italy

    NASA Astrophysics Data System (ADS)

    Castro-Jiménez, J.; Eisenreich, S. J.; Mariani, G.; Skejo, H.; Umlauf, G.

    2012-09-01

    The objective of this work was to assess the atmospheric occurrence, seasonal variations and deposition of dioxin-like pollutants (17 PCDD/Fs + 12 DL-PCBs) in sub-alpine northern Italy. A total of 108 weekly integrated samples (aerosol + gas phases) were collected during a 1-year period (2005-2006) at the Ispra EMEP site (Northern Italy, 45°49'N, 8°38'E). Atmospheric loadings into Lake Maggiore were also estimated by implementing a deposition model. ∑2,3,7,8-PCDD/F atmospheric total concentrations were dominated by the aerosol-bound fraction which ranged from 50 to 3080 (1-215 WHO98 TEQ) fg m-3. In contrast DL-PCB levels were dominated by the gas phase concentrations and varied from 1800 to 14800 (1-5 WHO98 TEQ) fg m-3. The aerosol and gas phase concentrations of PCDD/Fs and DL-PCBs exhibited a similar seasonality (higher values in winter time for aerosol-bound contaminants and lower concentrations for gas phase contaminants) in spite of their different environmental sources and properties. Estimated total atmospheric (dry + wet) depositional fluxes of dioxin-like pollutants in sub-alpine northern Italy were ˜0.2-˜9.5 ng m-2 d-1, with wet deposition dominating. Total atmospheric inputs (2,3,7,8-PCDD/Fs + DL-PCBs) into Lake Maggiore ranged from 14 to 304 g y-1. Higher environmental concentrations of dioxin-like pollutants in sub-alpine northern Italy are expected in the cold season and in rainy days due to a combined effect of stagnant atmospheric conditions (low winds), household wood burning in the region and higher pollutant loads via rainfall in winter.

  8. Atmospheric dry deposition on pines in the Eastern Brook Lake Watershed, Sierra Nevada, California

    NASA Astrophysics Data System (ADS)

    Bytnerowicz, Andrzej; Dawson, P. J.; Morrison, C. L.; Poe, M. P.

    Atmospheric dry deposition to branches of Pinus contorta and P. albicaulis was measured during summer 1987 in a sub-alpine zone at Eastern Brook Lake Watershed (EBLW), eastern Sierra Nevada, California. Results are presented as deposition fluxes of NO 3-, SO 42-, PO 43-, Cl -, F -, NH 4+, Ca 2+, Mg 2+, Na +, K +, Zn 2+, Fe 3+, Mn 2+, Pb 2+ and H +, and compared with other locations in California and elsewhere. Deposition fluxes of anions and cations to the pine branches were low, several times lower than the values determined near the Emerald Lake Watershed (ELW), another sub-alpine location in the western Sierra Nevada. The sums of deposition fluxes of the measured cations and anions to pine surfaces were similar, in contrast to the ELW location where the sums of cation fluxes were much higher than the sums of anion fluxes. A strong positive correlation between depositions of NO 3- and NH 4+, as well as SO 42- and Ca 2+, suggested that large portions of these ions might have originated from particulate NH 4NO 3 and CaSO 4 deposited on pine surfaces. An estimated total N dry deposition (surface deposition of NO 3- and NH 4+ and internal uptake of NO 2 and HNO 3) to the forested area of the EBLW was 29.54 eq ha -1 yr - (about 414 g H ha -1 yr -1).

  9. Open Air Silicon Deposition by Atmospheric Pressure Plasma under Local Ambient Gas Control

    NASA Astrophysics Data System (ADS)

    Naito, Teruki; Konno, Nobuaki; Yoshida, Yukihisa

    2015-09-01

    In this paper, we report open air silicon (Si) deposition by combining a silane free Si deposition technology and a newly developed local ambient gas control technology. Recently, material processing in open air has been investigated intensively. While a variety of materials have been deposited, there were only few reports on Si deposition due to the susceptibility to contamination and the hazardous nature of source materials. Since Si deposition is one of the most important processes in device fabrication, we have developed open air silicon deposition technologies in BEANS project. For a clean and safe process, a local ambient gas control head was designed. Process gas leakage was prevented by local evacuation, and air contamination was shut out by inert curtain gas. By numerical and experimental investigations, a safe and clean process condition with air contamination less than 10 ppm was achieved. Si film was deposited in open air by atmospheric pressure plasma enhanced chemical transport under the local ambient gas control. The film was microcrystalline Si with the crystallite size of 17 nm, and the Hall mobility was 2.3 cm2/V .s. These properties were comparable to those of Si films deposited in a vacuum chamber. This research has been conducted as one of the research items of New Energy and Industrial Technology Development Organization ``BEANS'' project.

  10. On-line coating of glass with tin oxide by atmospheric pressure chemical vapor deposition.

    SciTech Connect

    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.

    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

  11. Estimating Chemical Exchange between Atmospheric Deposition and Forest Canopy in Guizhou, China.

    PubMed

    Li, Wei; Gao, Fang; Liao, Xueqin

    2013-01-01

    To evaluate the effects of atmospheric deposition on forest ecosystems, wet-only precipitation and throughfall samples were collected in two forest types (Masson pine [ Lamb.] forests and mixed conifer and broadleaf forests) in the Longli forest in the Guizhou province of southwestern China for a period of 21 successive months from April 2007 to December 2008. The pH and chemical components of precipitation and throughfall were analyzed. In addition, the canopy budget model was applied to distinguish between in-canopy and atmospheric sources of chemical compounds. Canopy leaching and total potentially acidifying deposition fluxes were calculated. The results showed that the average pH and the concentration of ions in throughfall were higher than those in precipitation, with the exception of the NH concentration. Dry deposition of S and N accumulated more in Masson pine forests than in mixed conifer and broadleaf forests. Canopy leaching was the most significant source of base cations in forest throughfall, which was higher in the mixed forests than in the coniferous forests. Anions in throughfall deposition in Masson pine forests exceeded those in the mixed forests. Higher total potentially acidifying deposition fluxes reflected the more effective amounts of acid delivered to Masson pine forests compared with mixed conifer and broadleaf forests. In addition, acid deposition induced the leaching and loss of nutrient ions such as Mg, K, and Ca. Although the trees of the studied areas have not shown any symptoms of cation loss, a potentially harmful influence was engendered by atmospheric deposition in the two forest types in the Longli area.

  12. Nutrient and trace metals atmospheric deposition in the western Mediterranean: source apportionment

    NASA Astrophysics Data System (ADS)

    Desboeufs, Karine; Bon Nguyen, Elisabeth; Simeoni, Pasquale; Dulac, François

    2015-04-01

    Mediterranean Sea is a typical LNLC region particularly well adapted to assess the role of ocean-atmosphere exchanges. Throughout the summer stratification period when diffusion through the thermocline is low, atmospheric inputs become the main external source of nutrients to the surface open waters of the MS, mostly by wet deposition in the western basin.Here, we show a 3-yr time continuous series of nutrient (N, P) and trace metals (Cr, Cu, Fe, P, V, Zn) total deposition fluxes in Corsica. Between March 2008 and May 2011, a monitoring station was operated with a weekly sampling time step at Galeria (42.44°N; 8.65°E) on the western coast of Corsica in the framework of the projects DUNE (a Dust Experiment in a Low Nutrient Low Chlorophyll Ecosystem) and then ChArMEx (the Chemistry-Aerososl Mediterranean Experiment). Monthly fluxes were measured to assess the temporal variability of the measured elements over the Western Mediterranean. Nutrients deposition presented a clear seasonal pattern which was different for each studied nutrients, emphasizing a difference of sources for the nutrients. The results show no dust event larger than 0.68 g m-2 so that the maximum yearly flux was among the lowest ever observed in Corsica (1.7 g m-2 y-1). One dust deposition event could contribute up to 30% of yearly deposition fluxes of nutrient and trace metals, confirming the high temporal variability of atmospheric deposition. However a source apportionment work via statistical methods shows that the yearly deposition fluxes of considered nutrient and trace metals were dominated by anthropogenic sources, except for Fe. Acknowledgements: DUNE project was funded by ANR. ChArMEx (http://charmex.lsce.ipsl.fr) is funded by CNRS/INSU, ADEME, CEA and Météo-France in the framework of the programme MISTRALS (http://www.mistrals-home.org)

  13. Estimating Chemical Exchange between Atmospheric Deposition and Forest Canopy in Guizhou, China.

    PubMed

    Li, Wei; Gao, Fang; Liao, Xueqin

    2013-01-01

    To evaluate the effects of atmospheric deposition on forest ecosystems, wet-only precipitation and throughfall samples were collected in two forest types (Masson pine [ Lamb.] forests and mixed conifer and broadleaf forests) in the Longli forest in the Guizhou province of southwestern China for a period of 21 successive months from April 2007 to December 2008. The pH and chemical components of precipitation and throughfall were analyzed. In addition, the canopy budget model was applied to distinguish between in-canopy and atmospheric sources of chemical compounds. Canopy leaching and total potentially acidifying deposition fluxes were calculated. The results showed that the average pH and the concentration of ions in throughfall were higher than those in precipitation, with the exception of the NH concentration. Dry deposition of S and N accumulated more in Masson pine forests than in mixed conifer and broadleaf forests. Canopy leaching was the most significant source of base cations in forest throughfall, which was higher in the mixed forests than in the coniferous forests. Anions in throughfall deposition in Masson pine forests exceeded those in the mixed forests. Higher total potentially acidifying deposition fluxes reflected the more effective amounts of acid delivered to Masson pine forests compared with mixed conifer and broadleaf forests. In addition, acid deposition induced the leaching and loss of nutrient ions such as Mg, K, and Ca. Although the trees of the studied areas have not shown any symptoms of cation loss, a potentially harmful influence was engendered by atmospheric deposition in the two forest types in the Longli area. PMID:23673825

  14. National Acid Precipitation Assessment Program (NAPAP) Interim Assessment: the causes and effects of acidic deposition. Volume 4. Effects of acidic deposition

    SciTech Connect

    Not Available

    1987-01-01

    This volume on Effects of Acidic Deposition is the last in a four-volume set which comprises the NAPAP Interim Assessment. It contains five individual chapters covering (6) Agricultural Crops, (7) Forests, (8) Aquatic Systems, (9) Materials, and (10) Human Health and Visibility. Volume III, Atmospheric Processes and Deposition, has two chapters on (4) Atmospheric Processes, and (5) Acidic Deposition and Air Quality. Volume II, Emissions and Controls, contains three chapters on (1) Historical Emissions, (2) Emission Control Technologies, and (3) Future Emissions. Each of these chapters describes the National Program's research orientation and major conclusions within each of the ten primary areas of substantive concern. In order to learn how these first-order conclusions relate to the issue of acidic deposition in an overall, or synoptic, sense, the reader is directed to Volume I, Executive Summary, where the conclusions from each of the ten subject chapters are distilled in a manner that will allow interested parties to quickly reference the status of a variety of factors that pertain to the scientific understanding of acidic deposition.

  15. Tracing industrial ammonium in atmospheric deposition in the Athabasca Oil Sands Region, Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Mayer, B.; Proemse, B. C.; Fenn, M. E.

    2013-12-01

    The expanding industrial development in the Athabasca oil sands region (AOSR) in northeastern Alberta, Canada, has raised concerns about increasing nitrogen (N) emissions from oil sands operations and their potential effects on the surrounding terrestrial and aquatic ecosystems. Stable isotope techniques may help to trace industrial emissions provided that they are isotopically distinct from background isotope ratios of atmospheric N compounds. Ammonium deposition rates (NH4-N) typically exceed nitrate deposition rates (NO3-N) in the AOSR (Proemse et al., 2013), suggesting that emissions of reduced nitrogen compounds play a significant role for the atmospheric nitrogen budget in the AOSR. We collected atmospheric ammonium in open field bulk deposition and throughfall using ion exchange resins over ~6 months time periods from summer 2007 to summer 2011 located at distances between 3 to 113 km to one of the major oil sands developments in the AOSR. Ammonium deposition rates and δ15N-NH4 values were determined using ion chromatography and the ammonium diffusion method (Sebilo et al., 2004) on resin extracts. Atmospheric ammonium deposition rates in open field bulk collectors and throughfall collectors ranged from 1.0 to 4.7 kg ha-1 yr-1 NH4-N, and from 1.0 to 18.3 kg ha-1 yr-1 NH4-N, respectively. δ15N-NH4 values varied from -6.3 to +14.8‰ with the highest δ15N values typically associated with elevated NH4-N deposition rates. δ15N-NH4 values of up to +20.1‰ were observed for industrially emitted NH4 in particulate matter (PM2.5) emissions (Proemse et al., 2012) suggesting that industrial NH3 and NH4 emissions are associated with elevated δ15N values providing a potential tracer. Applying a two-end-member mixing analysis using a background δ15N-NH4 value of -3.6‰ for summer and -3.2‰ for winter periods revealed that particularly sites within ~30 km radius from the main oil sands developments are significantly affected by industrial contributions to

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

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Zhang, L.; Pan, Y.; Wang, Y.; Paulot, F.; Henze, D. K.

    2015-09-01

    Rapid Asian industrialization has led to increased downwind atmospheric nitrogen deposition 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 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 high-NH3 emissions reflect its intensive agricultural activities. We find Asian NH3 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 of 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 estimates 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 (22 %), and transportation (18

  17. Deposition of fixed atmospheric nitrogen and foliar nitrogen content of bryophytes and Calluna vulgaris (L.) Hull.

    PubMed

    Pitcairn, C E; Fowler, D; Grace, J

    1995-01-01

    Atmospheric deposition of fixed nitrogen as nitrate and ammonium in rain and by dry deposition of nitrogen dioxide, nitric acid and ammonia has increased throughout Europe during the last two decades, from 2-6 kg N ha(-1) year(-1) to 15-60 kg N ha(-1) year(-1). The nitrogen contents of bryophytes and the ericaceous shrub Calluna vulgaris have been measured at a range of sites, with the objective of showing the degree to which nitrogen deposition is reflected in foliar plant nitrogen. Tissue nitrogen concentrations of herbarium bryophyte samples and current samples of the same species collected from the same sites were compared. No significant change in tissue nitrogen was recorded at a remote site in north-west Scotland where nitrogen inputs are small (< 6 kg N ha(-1) year(-1)). Significant increases in tissue N occurred at four sites ranging from 38% in central Scotland to 63% in Cumbria where nitrogen inputs range from 15 to 30 kg N ha(-1) year(-1). The relationships found between the estimated input of atmospheric nitrogen and the tissue nitrogen content of the selected bryophytes and Calluna at the sites investigated were found to be generally linear and fitted the form N(tissue) = 0.62 + 0.022 N(dep) for bryophytes and N(tissue) = 0.83 + 0.045 N(dep) for Calluna. There was thus an increase in total tissue nitrogen of 0.02 mg g(-1) dry weight for bryophytes and 0.045 mg g(-1) dry weight for Calluna for an increase in atmospheric nitrogen deposition of 1 kg ha(-1) year(-1). The lowest concentrations were found in north-west Scotland and the highest in Cumbria and the Breckland heaths of East Anglia, both areas of high atmospheric nitrogen deposition (30-40 kg N ha(-1) year(-1)). The implications of increased tissue nitrogen content in terms of vegetation change are discussed. Changes in atmospheric nitrogen deposition with time were also examined using measured values and values inferred from tissue nitrogen content of mosses. The rate of increase in nitrogen

  18. The effect of atmospheric nitrogen deposition on marine nitrogen cycling throughout the global ocean

    NASA Astrophysics Data System (ADS)

    Somes, Christopher; Oschlies, Andreas

    2014-05-01

    The rapidly increasing rate of anthropogenic nitrogen deposition has the potential to perturb marine ecosystems and biogeochemical cycles because nitrogen is one of the major limiting nutrients in the ocean. We use an Earth System Climate Model that includes ocean biogeochemistry to assess the impact of atmospheric nitrogen deposition. Experiments are conducted where we artificially add nitrogen to nearly all locations individually throughout the global surface ocean using a nitrogen deposition rate of 700 mg N m-2 yr-1, which is consistent with modern estimates near industrial areas. We identify oceanic "biomes" that respond differently to atmospheric nitrogen deposition. (1) When nitrogen is deposited near oxygen minimum zones where water column denitrification occurs, locally increased primary production stimulates additional denitrification. Since water column denitrification removes 7 mol N for every mol N of newly formed organic matter respired, the global oceanic nitrogen inventory declines in response to nitrogen deposition in these areas. This slow, but steady decline persists for at least 1,000 years. (2) When nitrogen is deposited above shallow continental shelves where benthic denitrification occurs, our benthic denitrification model predicts an increase that is nearly equal to the nitrogen deposited and thus no net change in the global nitrogen inventory. (3) When nitrogen is deposited into the high latitude open ocean far removed from nitrogen fixation and denitrification, all of this deposited nitrogen initially accumulates in the ocean. This nitrogen eventually circulates into the tropical oxygen minimum zones where it fuels additional primary production and denitrification, which removes nitrogen at a rate equal to the deposition after 1,000 years and leads to a stable, but increased nitrogen inventory in our model. (4) When nitrogen is deposited into the open ocean where nitrogen fixation occurs, nitrogen fixation decreases due to less nitrogen

  19. Atmospheric dry deposition of sulfur and nitrogen in the Athabasca Oil Sands Region, Alberta, Canada.

    PubMed

    Hsu, Yu-Mei; Bytnerowicz, Andrzej; Fenn, Mark E; Percy, Kevin E

    2016-10-15

    Due to the potential ecological effects on terrestrial and aquatic ecosystems from atmospheric deposition in the Athabasca Oil Sands Region (AOSR), Alberta, Canada, this study was implemented to estimate atmospheric nitrogen (N) and sulfur (S) inputs. Passive samplers were used to measure ambient concentrations of ammonia (NH3), nitrogen dioxide (NO2), nitric acid/nitrous acid (HNO3/HONO), and sulfur dioxide (SO2) in the AOSR. Concentrations of NO2 and SO2 in winter were higher than those in summer, while seasonal differences of NH3 and HNO3/HONO showed an opposite trend, with higher values in summer. Concentrations of NH3, NO2 and SO2 were high close to the emission sources (oil sands operations and urban areas). NH3 concentrations were also elevated in the southern portion of the domain indicating possible agricultural and urban emission sources to the southwest. HNO3, an oxidation endpoint, showed wider ranges of concentrations and a larger spatial extent. Concentrations of NH3, NO2, HNO3/HONO and SO2 from passive measurements and their monthly deposition velocities calculated by a multi-layer inference model (MLM) were used to calculate dry deposition of N and S. NH3 contributed the largest fraction of deposited N across the network, ranging between 0.70-1.25kgNha(-1)yr(-1), HNO3/HONO deposition ranged between 0.30-0.90kgNha(-1)yr(-1), and NO2 deposition between 0.03-0.70kgNha(-1)yr(-1). During the modeled period, average dry deposition of the inorganic gaseous N species ranged between 1.03 and 2.85kgNha(-1)yr(-1) and SO4-S deposition ranged between 0.26 and 2.04kgha(-1)yr(-1). Comparisons with co-measured ion exchange resin throughfall data (8.51kgSha(-1)yr(-1)) indicate that modeled dry deposition combined with measured wet deposition (1.37kgSha(-1)yr(-1)) underestimated S deposition. Gas phase NH3 (71%) and HNO3 plus NO2 (79%) dry deposition fluxes dominated the total deposition of NH4-N and NO3-N, respectively.

  20. Atmospheric dry deposition of sulfur and nitrogen in the Athabasca Oil Sands Region, Alberta, Canada.

    PubMed

    Hsu, Yu-Mei; Bytnerowicz, Andrzej; Fenn, Mark E; Percy, Kevin E

    2016-10-15

    Due to the potential ecological effects on terrestrial and aquatic ecosystems from atmospheric deposition in the Athabasca Oil Sands Region (AOSR), Alberta, Canada, this study was implemented to estimate atmospheric nitrogen (N) and sulfur (S) inputs. Passive samplers were used to measure ambient concentrations of ammonia (NH3), nitrogen dioxide (NO2), nitric acid/nitrous acid (HNO3/HONO), and sulfur dioxide (SO2) in the AOSR. Concentrations of NO2 and SO2 in winter were higher than those in summer, while seasonal differences of NH3 and HNO3/HONO showed an opposite trend, with higher values in summer. Concentrations of NH3, NO2 and SO2 were high close to the emission sources (oil sands operations and urban areas). NH3 concentrations were also elevated in the southern portion of the domain indicating possible agricultural and urban emission sources to the southwest. HNO3, an oxidation endpoint, showed wider ranges of concentrations and a larger spatial extent. Concentrations of NH3, NO2, HNO3/HONO and SO2 from passive measurements and their monthly deposition velocities calculated by a multi-layer inference model (MLM) were used to calculate dry deposition of N and S. NH3 contributed the largest fraction of deposited N across the network, ranging between 0.70-1.25kgNha(-1)yr(-1), HNO3/HONO deposition ranged between 0.30-0.90kgNha(-1)yr(-1), and NO2 deposition between 0.03-0.70kgNha(-1)yr(-1). During the modeled period, average dry deposition of the inorganic gaseous N species ranged between 1.03 and 2.85kgNha(-1)yr(-1) and SO4-S deposition ranged between 0.26 and 2.04kgha(-1)yr(-1). Comparisons with co-measured ion exchange resin throughfall data (8.51kgSha(-1)yr(-1)) indicate that modeled dry deposition combined with measured wet deposition (1.37kgSha(-1)yr(-1)) underestimated S deposition. Gas phase NH3 (71%) and HNO3 plus NO2 (79%) dry deposition fluxes dominated the total deposition of NH4-N and NO3-N, respectively. PMID:27295600

  1. Enhanced acid rain and atmospheric deposition of nitrogen, sulfur and heavy metals in Northern China

    NASA Astrophysics Data System (ADS)

    Pan, Y.; Wang, Y.

    2013-12-01

    Atmospheric deposition is known to be important mechanism reducing air pollution. In response to the growing concern on the potential effects of the deposited material entering terrestrial and aquatic environments as well as their subsequent health effects, since 2007 we have established a 10-site monitoring network in Northern China, where particularly susceptible to severe air pollution. Wet and dry deposition was collected using an automatic wet-dry sampler. The presentation will focus on the new results of atmospheric deposition flux for a number of chemical species, such as nutrients (e.g. nitrogen and phosphorus), acidic matters (e.g. sulfur and proton), heavy metals and Polycyclic Aromatic Hydrocarbons, etc. This is to our knowledge the first detailed element budget study in the atmosphere across Northern China. We find that: (1) Over the 3 year period, 26% of precipitation events in the target area were more acid than pH 5.60 and these acidic events occurred in summer and autumn. The annual volume-weighted mean (VWM) pH value of precipitation was lower than 5.60 at most sites, which indicated the acidification of precipitation was not optimistic. The primary ions in precipitation were NH4+, Ca2+, SO42- and NO3-, with 10-sites-average concentrations of 221, 216, 216 and 80 μeq L-1, respectively. The ratio of SO42- to NO3- was 2.7; suggesting SO42- was the dominant acid component. (2) The deposited particles were neutral in general and the pH value increased from rural area to industrial and coastal sites. It is not surprising to note that the annual VWM pH value of precipitation was higher than 5.60 at three urban sites (Beijing and Tianjin mega cities) and one coastal site near the Bohai Bay, considering the fact that high buffer capacity of alkaline component, gas NH3 and mineral aerosols, at these sites compared to other places. (3) The 10-sites annual total deposition amounts for sulfur and nitrogen compounds were 60 and 65 kg N/S ha-1 yr-1

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    PubMed

    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.

  5. Decreased Atmospheric Sulfur Deposition Across the Southeastern U.S.: When Will Watersheds Release Stored Sulfate?

    NASA Astrophysics Data System (ADS)

    Rice, K. C.; Scanlon, T. M.; Lynch, J. A.; Cosby, B. J., Jr.

    2014-12-01

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

    PubMed

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

    2014-09-01

    Emissions of sulfur dioxide (SO2) to the atmosphere lead to atmospheric deposition of sulfate (SO4(2-)), which is the dominant strong acid anion causing acidification of surface waters and soils in the eastern United States. 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 streamwater SO4(2-) concentrations have been observed in unglaciated watersheds. We calculated SO4(2-) 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 SO4(2-), 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 SO4(2-) over the next two decades. The specific years when the watersheds crossover from retaining to releasing SO4(2-) 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 SO4(2-) retention to release anticipates more widespread reductions in streamwater SO4(2-) concentrations in this region. PMID:25046800

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

    USGS Publications Warehouse

    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.

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

    PubMed

    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.

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

    USGS Publications Warehouse

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  11. Atmospheric deposition of toxics onto Massachusetts Bay—II. Polycyclic aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Golomb, D.; Ryan, D.; Underhill, J.; Wade, T.; Zembar, S.

    Wet and dry atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) was measured at biweekly intervals from 15 September 1992 to 16 September 1993 at two sites on Massachusetts Bay, Nahant, near Boston and Truro, near the tip of Cape Cod. Wet and dry deposition was measured using a conventional wet/dry collector, except that the dry bucket contained a layer of water in order to simulate the uptake of dry deposition onto a water surface. The PAHs were extracted from the aqueous solution/suspension by methylene chloride, preconcentrated by low-temperature evaporation, and analyzed by GC-MS. Dry and wet depositions of PAHs were significantly greater at Nahant than at Truro, due to the proximity of emission sources in the metropolitan Boston area. Highest deposition of PAHs was observed in the winter season. At Nahant, the following deposition rates (wet + dry) were observed in units of 10 4 ng m -2 yr -1: fluoroanthene, 13; phenanthrene, 11; pyrene, 9.8; chrysene, 5.3; and the potentially carcinogenic benzo(a) pyrene, 3. At Truro, the deposition rates were several fold lower. Polychlorinated biphenyls (PCBs) were not found above the detection limit of the analytical procedure.

  12. Atmospheric Nitrogen Deposition at Two Sites in an Arid Environment of Central Asia

    PubMed Central

    Li, Kaihui; Liu, Xuejun; Song, Wei; Chang, Yunhua; Hu, Yukun; Tian, Changyan

    2013-01-01

    Arid areas play a significant role in the global nitrogen cycle. Dry and wet deposition of inorganic nitrogen (N) species were monitored at one urban (SDS) and one suburban (TFS) site at Urumqi in a semi-arid region of central Asia. Atmospheric concentrations of NH3, NO2, HNO3, particulate ammonium and nitrate (pNH4+ and pNO3−) concentrations and NH4-N and NO3-N concentrations in precipitation showed large monthly variations and averaged 7.1, 26.6, 2.4, 6.6, 2.7 µg N m−3 and 1.3, 1.0 mg N L−1 at both SDS and TFS. Nitrogen dry deposition fluxes were 40.7 and 36.0 kg N ha−1 yr−1 while wet deposition of N fluxes were 6.0 and 8.8 kg N ha−1 yr−1 at SDS and TFS, respectively. Total N deposition averaged 45.8 kg N ha−1 yr−1at both sites. Our results indicate that N dry deposition has been a major part of total N deposition (83.8% on average) in an arid region of central Asia. Such high N deposition implies heavy environmental pollution and an important nutrient resource in arid regions. PMID:23840576

  13. Atmospheric occurrence, transport and deposition of polychlorinated biphenyls and hexachlorobenzene in the Mediterranean and Black Seas

    NASA Astrophysics Data System (ADS)

    Berrojalbiz, N.; Castro-Jiménez, J.; Mariani, G.; Wollgast, J.; Hanke, G.; Dachs, J.

    2014-04-01

    The Mediterranean and Black Seas are unique marine environments subject to important anthropogenic pressures due to direct and indirect loads of atmospheric inputs of organochlorine compounds (OCl) from primary and secondary sources. Here we report the results obtained during two east-west sampling cruises in June 2006 and May 2007 from Barcelona to Istanbul and Alexandria, respectively, where gas phase and aerosol samples were collected. Both matrices were analyzed for 41 polychlorinated biphenyls (PCBs), including dioxin-like congeners, and hexachlorobencene (HCB). The values reported in this study for gas phase HCB and ∑41PCB (LOD to 418.3 pg m-3 and from 81.99 to 931.6 pg m-3 respectively) are in the same range of those reported in former studies, possibly suggesting a limited decline in their atmospheric concentrations during the last decade for the Mediterranean region due to land base OCl sources. There is a clear influence of the direction of the air-mass on the atmospheric concentrations of PCBs, with higher concentrations when the air mass was from southern Europe, and the lowest concentrations for air masses coming from the SW Mediterranean and Atlantic Ocean. PCBs and HCB are close to air-water equilibrium for most sampling periods, thus resulting in low atmospheric deposition fluxes at open sea. This is consistent with the oligotrophic character of the Mediterranean Sea with a small influence of the biological pump capturing atmospheric PCBs. Therefore, degradation of gas-phase PCBs by OH radicals is estimated to be the main loss process of atmospheric PCBs during their transport over the Mediterranean Sea. Conversely, atmospheric residence times of HCB are predicted to be very long due to a lack of atmospheric degradation and low depositional fluxes due to concentrations at air-water equilibrium.

  14. Atmospheric occurrence, transport and deposition of polychlorinated biphenyls and hexachlorobenzene in the Mediterranean and Black seas

    NASA Astrophysics Data System (ADS)

    Berrojalbiz, N.; Castro-Jiménez, J.; Mariani, G.; Wollgast, J.; Hanke, G.; Dachs, J.

    2014-09-01

    The Mediterranean and Black seas are unique marine environments subject to important anthropogenic pressures due to direct and indirect loads of atmospheric inputs of organochlorine compounds (OCls) from primary and secondary sources. Here we report the results obtained during two east-west sampling cruises in June 2006 and May 2007 from Barcelona to Istanbul and Alexandria, respectively, where gas-phase and aerosol-phase samples were collected. Both matrices were analyzed for 41 polychlorinated biphenyls (PCBs), including dioxin-like congeners, and hexachlorobenzene (HCB). The values reported in this study for gas-phase HCB and ∑41PCB limit of detection (LOD) to 418.3 pg m-3 and from 81.99 to 931.6 pg m-3 respectively) are in the same range of those reported in former studies, possibly suggesting a limited decline in their atmospheric concentrations during the last decade for the Mediterranean region due to land-based OCl sources. There is a clear influence of the direction of the air mass on the atmospheric concentrations of PCBs, with higher concentrations when the air mass was from southern Europe, and the lowest concentrations for air masses coming from the SW Mediterranean and Atlantic Ocean. PCBs and HCB are close to air-water equilibrium for most sampling periods, thus resulting in low atmospheric deposition fluxes at open sea. This is consistent with the oligotrophic character of the Mediterranean Sea with a small influence of the biological pump capturing atmospheric PCBs. Therefore, degradation of gas-phase PCBs by OH radicals is estimated to be the main loss process of atmospheric PCBs during their transport over the Mediterranean Sea. Conversely, atmospheric residence times of HCB are predicted to be very long due to a lack of atmospheric degradation and low depositional fluxes due to concentrations at air-water equilibrium.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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).

  17. Estimating the natural background atmospheric deposition rate of mercury utilizing ombrotrophic bogs in southern Sweden.

    PubMed

    Bindler, R

    2003-01-01

    A critical gap in the understanding of the global cycling of mercury is the limited data describing the natural background atmospheric deposition rate of mercury before the advent of pollution. Existing estimates of the natural deposition rate are typically about 2-5 microg of Hg m(-2) year(-1) (see, for example, Swain et al. Science 1992, 257, 784-787), based on studies that generally rely on short, 210Pb-dated lake sediment and peat cores that span the past 150 years. Analyses of mercury in long peat cores in southcentral Sweden indicate that natural mercury deposition rates in the period 4000-500 BP were lower, about 0.5-1 microg of Hg m(-2) year(-1). This suggests that recent mercury accumulation rates in the peat (15-25 microg of Hg m(-2) year(-1)) and measured atmospheric deposition rates of mercury in Sweden over the past 3 decades (5-30 microg of Hg m(-2) year(-1)) (Munthe et al. Water, Air, Soil Pollut.: Focus 2001, 1, 299-310) are at least an order of magnitude greater than the prepollution deposition rate, rather than representing only a 3-5-fold increase, as has generally been estimated.

  18. Analysis of Atmospheric Nitrate Deposition in Lake Tahoe Using Multiple Oxygen Isotopes

    NASA Astrophysics Data System (ADS)

    McCabe, J. R.; Michalski, G. M.; Hernandez, L. P.; Thiemens, M. H.; Taylor, K.; Kendall, C.; Wankel, S. D.

    2002-12-01

    Lake Tahoe in the Sierra Nevada Mountain Range is world renown for its depth and water clarity bringing 2.2 million visitors per year resulting in annual revenue of \\1.6 billion from tourism. In past decades the lake has suffered from decreased water clarity (from 32 m plate depth to less than 20), which is believed to be largely the result of algae growth initiated by increased nutrient loading. Lake nutrients have also seen a shift from a nitrogen limited to a phosphorous limited system indicating a large increase in the flux of fixed nitrogen. Several sources of fixed nitrogen of have been suggested including surface runoff, septic tank seepage from ground water and deposition from the atmosphere. Bio-available nitrogen in the form of nitrate (NO_{3}$-) is a main component of this system. Recent studies have estimated that approximately 50% of the nitrogen input into the lake is of atmospheric origin (Allison et al. 2000). However, the impact and magnitude of atmospheric deposition is still one of the least understood aspects of the relationship between air and water quality in the Basin (TRPA Threshold Assessment 2002). The utility of stable isotopes as tracers of nitrate reservoirs has been shown in several studies (Bohlke et al. 1997, Kendall and McDonnell 1998, Durka et al. 1994). Stable nitrogen (δ15N) and oxygen (δ18O) isotopes have been implemented in a dual isotope approach to characterize the various nitrate sources to an ecosystem. While δ18O distinguishes between atmospheric and soil sources of nitrate, processes such as denitrification can enrich the residual nitrate in δ18O leaving a misleading atmospheric signature. The benefit of δ15N as a tracer for NO3- sources is the ability to differentiate natural soil, fertilizer, and animal or septic waste, which contain equivalent δ18O values. The recent implementation of multiple oxygen isotopes to measure Δ17O in nitrate has proven to be a more sensitive tracer of atmospheric deposition. The

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Photocatalytic anatase titanium dioxide thin films deposition by an atmospheric pressure blown arc discharge

    NASA Astrophysics Data System (ADS)

    Boscher, Nicolas D.; Olivier, Sébastien; Maurau, Rémy; Bulou, Simon; Sindzingre, Thierry; Belmonte, Thierry; Choquet, Patrick

    2014-08-01

    TiO2 thin films are deposited by means of an atmospheric pressure blown arc discharge fed with nitrogen and titanium bis(acetylacetonate) diisopropoxide (TIPO) as precursor. Different power densities and distances between the plasma nozzle, the precursor injector and the substrate are investigated and different morphologies, compositions and crystallinities of the coatings are generated. The photocatalytic properties of the coatings, determined from the degradation of stearic acid shined by a 254 nm UV light, are shown to be strongly related to the film characteristic and therefore to the deposition parameters.

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

    NASA Astrophysics Data System (ADS)

    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 < 0.001) and predictions were also reasonable for a range of other herbicides, but a source other than 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

  2. Chesapeake Bay atmospheric deposition study phase 1: July 1990-June 1991 appendices

    SciTech Connect

    Not Available

    1994-03-01

    A one-year study (6/90-7/91) was conducted to estimate the deposition of atmospheric contaminants to the Maryland portion of the Chesapeake Bay. The studied contaminants included the trace elements polychlorinated biphenyl (PCBs) congeners, and polycyclic aromatic hydrocarbons (PAHs). Weekly integrated samples of aerosol and precipitation were collected for elemental constituents at two sites, one on the northeastern (Wye) and one on the mid-bay western (Elms) Maryland shore. Organic contaminants in precipitation samples were collected bi-weekly at the Elms site only. Major elements in wet deposition, as related to acid rain monitoring, are being measured at these sites by other groups.

  3. Chesapeake Bay atmospheric deposition study phase 1: July 1990-June 1991

    SciTech Connect

    Baker, J.E.; Church, T.M.; Ondov, J.M.; Scudlark, J.R.; Conko, K.M.

    1992-12-01

    A one-year study (6/90-7/91) was conducted to estimate the deposition of atmospheric contaminants to the Maryland portion of the Chesapeake Bay. The studied contaminants included the trace elements polychlorinated biphenyl (PCBs) congeners, and polycyclic aromatic hydrocarbons (PAHs). Weekly integrated samples of aerosol and precipitation were collected for elemental constituents at two sites, one on the northeastern (Wye) and one on the mid-bay western (Elms) Maryland shore. Organic contaminants in precipitation samples were collected bi-weekly at the Elms site only. Major elements in wet deposition, as related to acid rain monitoring, are being measured at these sites by other groups.

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

    PubMed Central

    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 <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. PMID:25802810

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

    PubMed

    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 <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.

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

    NASA Astrophysics Data System (ADS)

    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

  7. Nitrogen Accumulation and Partitioning in High Arctic Tundra from Extreme Atmospheric N Deposition Events

    NASA Astrophysics Data System (ADS)

    Phoenix, G. K.; Osborn, A.; Blaud, A.; Press, M. C.; Choudhary, S.

    2013-12-01

    Arctic ecosystems are threatened by pollution from extreme atmospheric nitrogen (N) deposition events. These events occur from the long-range transport of reactive N from pollution sources at lower latitudes and can deposit up to 80% of the annual N deposition in just a few days. To date, the fate and impacts of these extreme pollutant events has remained unknown. Using a field simulation study, we undertook the first assessment of the fate of acutely deposited N on arctic tundra. Extreme N deposition events were simulated on field plots at Ny-Ålesund, Svalbard (79oN) at rates of 0, 0.04, 0.4 and 1.2 g N m-2 yr-1 applied as NH4NO3 solution over 4 days, with 15N tracers used in the second year to quantify the fate of the deposited N in the plant, soil, microbial and leachate pools. Separate applications of 15NO3- and 15NH4+ were also made to determine the importance of N form in the fate of N. Recovery of the 15N tracer at the end of the first growing season approached 100% of the 15N applied irrespective of treatment level, demonstrating the considerable capacity of High Arctic tundra to capture pollutant N from extreme deposition events. Most incorporation of the 15N was found in bryophytes, followed by the dominant vascular plant (Salix polaris) and the microbial biomass of the soil organic layer. Total recovery remained high in the second growing season (average of 90%), indicating highly conservative N retention. Between the two N forms, recovery of 15NO3- and 15NH4+ were equal in the non-vascular plants, whereas in the vascular plants (particularly Salix polaris) recovery of 15NO3- was four times higher than of 15NH4+. Overall, these findings show that High Arctic tundra has considerable capacity to capture and retain the pollutant N deposited in acute extreme deposition events. Given they can represent much of the annual N deposition, extreme deposition events may be more important than increased chronic N deposition as a pollution source. Furthermore

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

    NASA Astrophysics Data System (ADS)

    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.

  9. The effects of atmospheric nitrogen deposition in the Rocky Mountains of Colorado and southern Wyoming -- a synthesis and critical assessment of published results

    USGS Publications Warehouse

    Burns, Douglas A.

    2002-01-01

    The Rocky Mountain region of Colorado and southern Wyoming receives as much as 7 kilograms per hectare per year ((kg/ha)/yr) of atmospheric nitrogen (N) deposition, an amount that may have caused changes in aquatic and terrestrial life in otherwise pristine ecosystems. The Rocky Mountain National Park, in its role of protecting air-quality related values under provisions of the Clean Air Act Amendments of 1977, has provided support for this synthesis and critical assessment of published literature on the effects of atmospheric N deposition. Results from published studies indicate a long-term increase in the rate of atmospheric N deposition during the 20th century, but no region-wide increase during the past 2 decades, although the rate of atmospheric N deposition has increased at three sites east of the Continental Divide in the Front Range region since the mid-1980s. Much of the increase in atmospheric N deposition at all three sites has resulted from an increase in the ammonium concentrations of wet deposition; this suggests an increase in contributions from agricultural areas or from vehicle traffic east of the Rocky Mountains. Lakes at two study sites in the Front Range (Loch Vale and Green Lakes Valley) had NO3- concentrations of 30 to 40 micromoles per liter (?mol/L) during early spring snowmelt and remained at 5 to 10 ?mol/L during summer. Retention of N in atmospheric wet deposition in some sub-catchments of these lakes was less than 50 percent, which reflects an advanced stage of N saturation. Nitrate concentrations in surface waters west of the Continental Divide were lower -- often less than 10 ?mol/L during snowmelt and less than 2 ?mol/L during summer -- than surface waters east of the Divide, except in areas such as the Mt. Zirkel Wilderness that receive elevated amounts of atmospheric N deposition of 4 to 5 (kg/ha)/yr. Atmospheric N deposition in the Front Range east of the Divide may have altered the composition of alpine tundra-plant communities

  10. Biodiversity of European grasslands - gradient studies to investigate impacts of atmospheric nitrogen deposition on grasslands

    NASA Astrophysics Data System (ADS)

    Stevens, C. J.; Gowing, D. J.

    2009-04-01

    Experiments have suggested that reactive nitrogen deposition may reduce species richness in plant communities. However, until recently there was no clear evidence that regional air pollution was actually reducing biodiversity on a regional scale.. An extensive field survey of acidic grasslands along a gradient of atmospheric nitrogen deposition in the UK showed a dramatic decline in plant-species richness with increasing atmospheric nitrogen deposition [1, 2]. Changes in soil chemistry were also observed [3]. Combining the results of this gradient study with experimental manipulations allowed us to estimate the timescale of the observed change in species richness. The BEGIN project (Biodiversity of European Grasslands - the Impact of Atmospheric Nitrogen Deposition) is a collaborative EUROCORES project between The Open University (UK), Manchester Metropolitan University (UK), Bordeaux University (France), Utrecht University (The Netherlands) and The University of Bremen (Germany). This project builds on the results collected in the UK survey to investigate changes in species richness further. In addition to the 68 acid grasslands already surveyed in the UK, the BEGIN project has surveyed 70 acidic grassland sites throughout the Atlantic biogeographic region of Europe. At each site, data were collected on species composition, soil chemistry and plant-tissue chemistry. This data set is being combined with a field experiment replicated across three grasslands (Norway, Wales and Aquitaine) of the same community and an analysis of historical changes in species composition. Surveys have also been conducted in a contrasting grassland system; calcareous grasslands belonging to the Mesobromion alliance. Initial results of the BEGIN project will be presented, demonstrating declines in species richness and changes in species composition across the Atlantic Biogeographic Zone of Europe during the last 70 years that can be related to nitrogen deposition. We will also report

  11. Atmospheric deposition of polycyclic aromatic hydrocarbons to Atlantic Canada: geographic and temporal distributions and trends 1980-2001.

    PubMed

    Brun, Guy L; Vaidya, Om C; Léger, Martin G

    2004-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants. The semivolatile organic compounds may disperse into the atmosphere by direct input from several sources such as the burning of fossil fuels, from motor vehicle emissions, and forest fires. Once in the atmosphere, they may travel great distances before being deposited to the earth's surface by the scavenging action of rain and snow. Up to 14 PAHs were determined in wet precipitation samples collected monthly from five sites in the four Canadian Atlantic Provinces during 1980-2001. The relatively more volatile PAHs (phenanthrene, fluoranthene, naphthalene, and pyrene) were predominant in the samples. Significant (P < 0.05) spatial variations in the deposition of some PAHs were observed among sites, but there were no consistent geographic patterns. Seasonal patterns were discernible with peak deposition for sigma6&14 PAHs occurring during the colder months of the year (December to March) and coinciding with higher energy consumption for heating and transport. The monthly volume weighed mean concentration for sigma6 PAHs has declined steadily since the mid-1980s at Kejimkujik National Park in southwest Nova Scotia, with a calculated half-life of 6.4 +/- 0.3 years. The maximum annual deposition flux of 20 microg m(-2) yr(-1) reached in 1985 for sigma6 PAHs decreased approximately 1 order of magnitude by the year 2000. The decrease in sigma6&14 PAHs for the region was found to be correlated (P < 0.05) with decreasing sulfate ion concentrations in the precipitation. The implementation of air pollution abatement programs in Canada, the United States, and elsewhere, switching to cleaner sources of energy and improved technology during the pastfew decades is most likely responsible for the observed decline. PMID:15112792

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

    PubMed

    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

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

    PubMed

    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.

  14. Variation in mineral content of red maple sap across an atmospheric deposition gradient

    SciTech Connect

    McCormick, L.H.

    1997-11-01

    Xylem sap was collected from red maple (Acer rubrum L.) trees during the spring of 1988 and 1989 at seven forest sites along an atmospheric deposition gradient in north central Pennsylvania and analyzed for pH and twelve mineral constituents. The objectives of the study were to examine the sources and patterns of variation in red maple sap chemistry across an atmospheric deposition gradient and to assess the feasibility of using sap analysis as an indicator of nutrient bioavailability. For most sap constituents, there was considerable spatial and temporal variation in concentration. Sources of variation included within and between site variation, date, and year of collection. The nature and extent of variation varied for different constituents. Site differences were similar in 1988 and 1989 for most sap constituents and for some constituents corresponded with differences in soil levels.

  15. Lead isotopes tracing weathering and atmospheric deposition in a small volcanic catchment

    NASA Astrophysics Data System (ADS)

    Négrel, Philippe; Petelet-Giraud, Emmanuelle; Guerrot, Catherine; Millot, Romain

    2015-09-01

    Lead isotopes were studied in soil and sediments of the small volcanic catchment in the Massif Central (France), a large area of Tertiary to Recent continental alkaline volcanism. The comparison of Pb and K (normalized to Zr) shows a linear evolution of weathering processes, whereby lead enrichment from atmospheric deposition is a major contributor explaining the deviation of several points from this line. A box model simulates the lead evolution in sediments from soil production on the hillslopes due to bedrock weathering and from anthropogenic input through atmospheric deposition and constrains the dynamics of sediment transfer. Lead isotope ratios decrease from bedrock to sediment and soil without any clear relationship when compared to lead contents. Pb isotopic compositions showed that most of the lead budget in sediment and soil results from bedrock weathering with influence of gasoline-additive-lead and past mining activities derived inputs, but no lead input from agricultural activity.

  16. Detection of Atmospheric Water Deposits in Porous Media Using the TDR Technique

    PubMed Central

    Nakonieczna, Anna; Kafarski, Marcin; Wilczek, Andrzej; Szypłowska, Agnieszka; Janik, Grzegorz; Albert, Małgorzata; Skierucha, Wojciech

    2015-01-01

    Investigating the intensity of atmospheric water deposition and its diurnal distribution is essential from the ecological perspective, especially regarding dry geographic regions. It is also important in the context of monitoring the amount of moisture present within building materials in order to protect them from excessive humidity. The objective of this study was to test a constructed sensor and determine whether it could detect and track changes in the intensity of atmospheric water deposition. An operating principle of the device is based on the time-domain reflectometry technique. Two sensors of different plate volumes were manufactured. They were calibrated at several temperatures and tested during field measurements. The calibration turned out to be temperature independent. The outdoor measurements indicated that the upper limits of the measurement ranges of the sensors depended on the volumes of the plates and were equal to 1.2 and 2.8 mm H2O. The respective sensitivities were equal to 3.2 × 10−3 and 7.5 × 10−3 g·ps−1. The conducted experiments showed that the construction of the designed device and the time-domain reflectometry technique were appropriate for detecting and tracing the dynamics of atmospheric water deposition. The obtained outcomes were also collated with the readings taken in an actual soil sample. For this purpose, an open container sensor, which allows investigating atmospheric water deposition in soil, was manufactured. It turned out that the readings taken by the porous ceramic plate sensor reflected the outcomes of the measurements performed in a soil sample. PMID:25871717

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

    PubMed

    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.

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

    PubMed

    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

  19. Sintering of Glass in Hydrous Atmospheres and its Implications for Welding of Volcanic Deposits

    NASA Astrophysics Data System (ADS)

    von Aulock, F. W.; Wadsworth, F. B.; Lavallée, Y.; Vasseur, J.

    2014-12-01

    Volcanic ash sintering can occur during hot deposition or upon reheating, and recently published models have improved our understanding of viscous sintering timescales at magmatic temperatures. However, in most volcanic environments, water is present either from meteoric or magmatic sources. Water significantly lowers the viscosity of liquids and therefore should alter the onset temperature and timescales of sintering. The diffusion of water in melts and glasses at low (sub-liquidus) temperatures and pressures, and the partitioning between water vapor and dissolved water species are poorly understood. We investigate the impact of a water rich Ar -atmosphere on viscous sintering at temperatures close to the glass transition. Synthetic near-spherical soda-lime silica glass beads with a well-constrained size of about 10-350μm (produced by Spheriglass) were heated in simultaneous thermal analyses of both differential scanning calorimetry and thermogravimetry. Glass transition temperature onset and mass stayed consistent under argon atmosphere during successive heating cycles at a rate of 10 °C.min-1. Contrastingly, preliminary results show that, when heated, closely packed in a water-argon atmosphere (1) there is a measurable water uptake during timescales as short as 2 hours, and (2) sintering is more efficient and densification takes place at lower temperatures and/or within shorter timescales. Sintering of volcanic materials reduces both porosity and permeability of volcanic products. The process of sintering is, however, limited by quenching of the material shortly after eruption. External water present during deposition could allow welding of pyroclastic deposits at conditions and timescales otherwise not achievable from the deposited pyroclasts alone.. Viscous sintering in a water-rich atmosphere may enhance resorption and encourage the formation of vesicle-free obsidian.

  20. Energy deposition and primary chemical products in Titan’s upper atmosphere

    NASA Astrophysics Data System (ADS)

    Lavvas, P.; Galand, M.; Yelle, R. V.; Heays, A. N.; Lewis, B. R.; Lewis, G. R.; Coates, A. J.

    2011-05-01

    Cassini results indicate that solar photons dominate energy deposition in Titan's upper atmosphere. These dissociate and ionize nitrogen and methane and drive the subsequent complex organic chemistry. The improved constraints on the atmospheric composition from Cassini measurements demand greater precision in the photochemical modeling. Therefore, in order to quantify the role of solar radiation in the primary chemical production, we have performed detailed calculations for the energy deposition of photons and photoelectrons in the atmosphere of Titan and we validate our results with the Cassini measurements for the electron fluxes and the EUV/FUV emissions. We use high-resolution cross sections for the neutral photodissociation of N 2, which we present here, and show that they provide a different picture of energy deposition compared to results based on low-resolution cross sections. Furthermore, we introduce a simple model for the energy degradation of photoelectrons based on the local deposition approximation and show that our results are in agreement with detailed calculations including transport, in the altitude region below 1200 km, where the effects of transport are negligible. Our calculated, daytime, electron fluxes are in good agreement with the measured fluxes by the Cassini Plasma Spectrometer (CAPS), and the same holds for the measured FUV emissions by the Ultraviolet Imaging Spectrometer (UVIS). Finally, we present the vertical production profiles of radicals and ions originating from the interaction of photons and electrons with the main components of Titan's atmosphere, along with the column integrated production rates at different solar zenith angles. These can be used as basis for any further photochemical calculations.

  1. The role of power plant atmospheric emissions in the deposition of nitrogen to the Chesapeake Bay

    SciTech Connect

    Miller, P.E.

    1994-12-31

    The Maryland Power Plant Research Program (PPRP) has sponsored research on several aspects of atmospheric nitrogen emissions, source attribution, deposition estimation and impact assessment since the mid-eighties. The results of these studies will be presented and discussed in the context of power plant emissions control impact on nitrogen loadings to the Chesapeake Bay and watershed. Information needs with respect to power plant contribution and emission control policy will be identified and discussed from the perspective of PPRP.

  2. A hybrid modeling approach for estimating reactive nitrogen deposition in Rocky Mountain National Park

    NASA Astrophysics Data System (ADS)

    Malm, William C.; Rodriguez, Marco A.; Schichtel, Bret A.; Gebhart, Kristi A.; Thompson, Tammy M.; Barna, Michael G.; Benedict, Katherine B.; Carrico, Christian M.; Collett, Jeffrey L.

    2016-02-01

    Changes in ecosystem function at Rocky Mountain National Park (RMNP) are occurring because of nitrogen deposition associated with emissions of nitrogen from sources in Colorado as well as other areas of the North American continent and beyond. Nitrogen species are in both reduced and oxidized forms. A year-long monitoring program was initiated to better understand their origins as well as the complex chemistry occurring during transport from source to receptor. Specifically, the goals of the study were to characterize the atmospheric concentrations of nitrogen species in gaseous, particulate, and aqueous phases in RMNP and to identify the emission sources of these various species. The apportionment strategy was designed to focus on differentiating between sources within and outside the state of Colorado and then further differentiate between sources along the Front Range of Colorado and the rest of Colorado. It was also desirous to identify the relative contributions to atmospheric nitrogen species from mobile sources, agricultural activities, and large and small point sources within the state of Colorado. The Particle Source Apportionment Technology (PSAT) module available in the chemical transport model, the Comprehensive Air quality Model with extensions (CAMx), is used to develop first-principle estimates of the contributions from different areas of North America. The CAMx_PSAT results are combined with measured species concentrations in a receptor modeling approach to develop final estimates of source apportionment of the various species' concentrations and deposition.

  3. Addressing the Impact of Atmospheric Nitrogen Deposition on Western European Grasslands.

    PubMed

    Stevens, C J; Gowing, D J G; Wotherspoon, K A; Alard, D; Aarrestad, P A; Bleeker, A; Bobbink, R; Diekmann, M; Dise, N B; Duprè, C; Dorland, E; Gaudnik, C; Rotthier, S; Soons, M B; Corcket, E

    2011-11-01

    There is a growing evidence base demonstrating that atmospheric nitrogen deposition presents a threat to biodiversity and ecosystem function in acid grasslands in Western Europe. Here, we report the findings of a workshop held for European policy makers to assess the perceived importance of reactive nitrogen deposition for grassland conservation, identify areas for policy development in Europe and assess the potential for managing and mitigating the impacts of nitrogen deposition. The importance of nitrogen as a pollutant is already recognized in European legislation, but there is little emphasis in policy on the evaluation of changes in biodiversity due to nitrogen. We assess the potential value of using typical species, as defined in the European Union Habitats Directive, for determining the impact of nitrogen deposition on acid grasslands. Although some species could potentially be used as indicators of nitrogen deposition, many of the typical species do not respond strongly to nitrogen deposition and are unlikely to be useful for identifying impact on an individual site. We also discuss potential mitigation measures and novel ways in which emissions from agriculture could be reduced.

  4. Atmospheric N deposition alters connectance, but not functional potential among saprotrophic bacterial communities.

    PubMed

    Freedman, Zachary B; Zak, Donald R

    2015-06-01

    The use of co-occurrence patterns to investigate interactions between micro-organisms has provided novel insight into organismal interactions within microbial communities. However, anthropogenic impacts on microbial co-occurrence patterns and ecosystem function remain an important gap in our ecological knowledge. In a northern hardwood forest ecosystem located in Michigan, USA, 20 years of experimentally increased atmospheric N deposition has reduced forest floor decay and increased soil C storage. This ecosystem-level response occurred concomitantly with compositional changes in saprophytic fungi and bacteria. Here, we investigated the influence of experimental N deposition on biotic interactions among forest floor bacterial assemblages by employing phylogenetic and molecular ecological network analysis. When compared to the ambient treatment, the forest floor bacterial community under experimental N deposition was less rich, more phylogenetically dispersed and exhibited a more clustered co-occurrence network topology. Together, our observations reveal the presence of increased biotic interactions among saprotrophic bacterial assemblages under future rates of N deposition. Moreover, they support the hypothesis that nearly two decades of experimental N deposition can modify the organization of microbial communities and provide further insight into why anthropogenic N deposition has reduced decomposition, increased soil C storage and accelerated phenolic DOC production in our field experiment. PMID:25943298

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

    PubMed

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

    PubMed

    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.

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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

  9. CAN Canopy Addition of Nitrogen Better Illustrate the Effect of Atmospheric Nitrogen Deposition on Forest Ecosystem?

    PubMed Central

    Zhang, Wei; Shen, Weijun; Zhu, Shidan; Wan, Shiqiang; Luo, Yiqi; Yan, Junhua; Wang, Keya; Liu, Lei; Dai, Huitang; Li, Peixue; Dai, Keyuan; Zhang, Weixin; Liu, Zhanfeng; Wang, Faming; Kuang, Yuanwen; Li, Zhian; Lin, Yongbiao; Rao, Xingquan; Li, Jiong; Zou, Bi; Cai, Xian; Mo, Jiangming; Zhao, Ping; Ye, Qing; Huang, Jianguo; Fu, Shenglei

    2015-01-01

    Increasing atmospheric nitrogen (N) deposition could profoundly impact community structure and ecosystem functions in forests. However, conventional experiments with understory addition of N (UAN) largely neglect canopy-associated biota and processes and therefore may not realistically simulate atmospheric N deposition to generate reliable impacts on forest ecosystems. Here we, for the first time, designed a novel experiment with canopy addition of N (CAN) vs. UAN and reviewed the merits and pitfalls of the two approaches. The following hypotheses will be tested: i) UAN overestimates the N addition effects on understory and soil processes but underestimates those on canopy-associated biota and processes, ii) with low-level N addition, CAN favors canopy tree species and canopy-dwelling biota and promotes the detritus food web, and iii) with high-level N addition, CAN suppresses canopy tree species and other biota and favors rhizosphere food web. As a long-term comprehensive program, this experiment will provide opportunities for multidisciplinary collaborations, including biogeochemistry, microbiology, zoology, and plant science to examine forest ecosystem responses to atmospheric N deposition. PMID:26059183

  10. CAN Canopy Addition of Nitrogen Better Illustrate the Effect of Atmospheric Nitrogen Deposition on Forest Ecosystem?

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Shen, Weijun; Zhu, Shidan; Wan, Shiqiang; Luo, Yiqi; Yan, Junhua; Wang, Keya; Liu, Lei; Dai, Huitang; Li, Peixue; Dai, Keyuan; Zhang, Weixin; Liu, Zhanfeng; Wang, Faming; Kuang, Yuanwen; Li, Zhian; Lin, Yongbiao; Rao, Xingquan; Li, Jiong; Zou, Bi; Cai, Xian; Mo, Jiangming; Zhao, Ping; Ye, Qing; Huang, Jianguo; Fu, Shenglei

    2015-06-01

    Increasing atmospheric nitrogen (N) deposition could profoundly impact community structure and ecosystem functions in forests. However, conventional experiments with understory addition of N (UAN) largely neglect canopy-associated biota and processes and therefore may not realistically simulate atmospheric N deposition to generate reliable impacts on forest ecosystems. Here we, for the first time, designed a novel experiment with canopy addition of N (CAN) vs. UAN and reviewed the merits and pitfalls of the two approaches. The following hypotheses will be tested: i) UAN overestimates the N addition effects on understory and soil processes but underestimates those on canopy-associated biota and processes, ii) with low-level N addition, CAN favors canopy tree species and canopy-dwelling biota and promotes the detritus food web, and iii) with high-level N addition, CAN suppresses canopy tree species and other biota and favors rhizosphere food web. As a long-term comprehensive program, this experiment will provide opportunities for multidisciplinary collaborations, including biogeochemistry, microbiology, zoology, and plant science to examine forest ecosystem responses to atmospheric N deposition.

  11. Impact of atmospheric deposition on algal growth in Lake Tahoe, CA

    NASA Astrophysics Data System (ADS)

    Paytan, A.; Mackey, K. R.; Jiang, Y.; Liston, A.; Allen, B.; Schladow, S. G.

    2010-12-01

    Lake Tahoe’s clarity has been declining over the past decades and it is important to understand the causes and consequences of this decline. Lake Tahoe’s clarity is determined by fine sediment particles and by nutrients. Nutrients affect lake clarity by promoting algae growth. Indeed primary productivity, the rate at which algae produce biomass through photosynthesis, has been increasing since 1959. Offshore, algae make the water greenish and less clear. The two nutrients that most affect algal growth in this system are nitrogen and phosphorus. Atmospheric deposition is an important source of nutrients to the lake contributing 55% of the nitrogen load and 15% of the phosphate load (State of the Lake Report - http://terc.ucdavis.edu/stateofthelake/StateOfTheLake2009.pdf). To evaluate if and how atmospheric deposition impacts phytoplankton growth and abundance we have preformed bioassay experiments with inorganic nutrient and aerosol additions during the summer of 2010. Our results indicate that, as expected for this season, nitrogen or combined nitrogen and phosphate induce growth. Our aerosol additions also induced growth and suggest that nutrients originating from aerosols are bio-available and can stimulate phytoplankton production. Atmospheric deposition can therefore affect lake clarity and should be monitored to ensure that the state of the lake does not deteriorate further.

  12. Determination of atmospheric nitrate particulate size distribution and dry deposition velocity for three distinct areas.

    PubMed

    Yang, Hsi-Hsien; Hsieh, Lien-Te; Cheng, Shih-Kai

    2005-09-01

    In this study, both atmospheric particulates and dry deposited particulates were collected at a highway intersection, coastal location and suburban area in Taichung, Taiwan for the characterization of nitrate containing particulates (NCPs) in size distribution and dynamic properties. Collected particulates were placed in contact with nitron (C20H16N4) to form distinctive products of NCPs, which were examined by a SEM. For total atmospheric particulates, the sum of NCP and non-nitrate containing particulate (NNCP), the average shape factor values are 1.69, 1.49, and 1.36 for the highway intersection, coastal area and suburban area, respectively. The calculated shape factors show no significant differences with sizes. Dry deposition fluxes and atmospheric concentrations at various size ranges were estimated. The mass distributed in fine particle range (deposition velocities (Vds) of total particulate are 2.5, 1.5, and 1.2 cm s(-1) for highway intersection, coastal area, and suburban area, respectively. The highest Vd was observed from samples taken at highway intersection, suggesting that dust resuspension and particulates from vehicles in the ambient air is of great significance. The Vds of total particulates range over three orders of magnitude for size ranges from 0.32 to 18 microm. The value of Vd increases with the diameter of particles significantly.

  13. CAN Canopy Addition of Nitrogen Better Illustrate the Effect of Atmospheric Nitrogen Deposition on Forest Ecosystem?

    PubMed

    Zhang, Wei; Shen, Weijun; Zhu, Shidan; Wan, Shiqiang; Luo, Yiqi; Yan, Junhua; Wang, Keya; Liu, Lei; Dai, Huitang; Li, Peixue; Dai, Keyuan; Zhang, Weixin; Liu, Zhanfeng; Wang, Faming; Kuang, Yuanwen; Li, Zhian; Lin, Yongbiao; Rao, Xingquan; Li, Jiong; Zou, Bi; Cai, Xian; Mo, Jiangming; Zhao, Ping; Ye, Qing; Huang, Jianguo; Fu, Shenglei

    2015-06-10

    Increasing atmospheric nitrogen (N) deposition could profoundly impact community structure and ecosystem functions in forests. However, conventional experiments with understory addition of N (UAN) largely neglect canopy-associated biota and processes and therefore may not realistically simulate atmospheric N deposition to generate reliable impacts on forest ecosystems. Here we, for the first time, designed a novel experiment with canopy addition of N (CAN) vs. UAN and reviewed the merits and pitfalls of the two approaches. The following hypotheses will be tested: i) UAN overestimates the N addition effects on understory and soil processes but underestimates those on canopy-associated biota and processes, ii) with low-level N addition, CAN favors canopy tree species and canopy-dwelling biota and promotes the detritus food web, and iii) with high-level N addition, CAN suppresses canopy tree species and other biota and favors rhizosphere food web. As a long-term comprehensive program, this experiment will provide opportunities for multidisciplinary collaborations, including biogeochemistry, microbiology, zoology, and plant science to examine forest ecosystem responses to atmospheric N deposition.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Estimates of atmospheric deposition of submicron particle-associated combustion derived organic contaminants to Chesapeake Bay

    SciTech Connect

    Leister, D.L. |; Baker, J.E.

    1994-12-31

    Once emitted into the atmosphere, combustion derived organic contaminants partition between gaseous and particle phases. In order to estimate the wet and dry removal of contaminants from the atmospheric to surface waters, it is necessary to measure gaseous and particle-associated contaminant concentrations because the deposition mechanisms of each phase differ. The authors estimate dry and wet depositional fluxes of polycyclic aromatic hydrocarbons (PAH) as a function of large and small particles to provide insight to the contribution of small particles to the overall atmospheric flux of organic contaminants to surface waters. Utilizing data gathered from concurrent measurements of 10 PAHs associated with particles in rain an in the atmosphere adjacent to Chesapeake Bay, and from PAH particle-size distribution data recently collected at Egbert, Ontario, calculated non-crustal PAH dry particle fluxes range from 40 to as high as 160 ng/m{sup 2}/month. Despite the lower estimated deposition velocity for noncrustal particles relative to that for partially crustal particles, non-crustal PAH particle fluxes are about a factor of five larger than those calculated for particles with a partial crustal component. Monthly wet fluxes of submicron particles range from 12 to 260 ng/m{sup 2}/month and in contrast to dry periods, are similar to those for large particles. Their calculations suggest that the atmospheric loading of submicron particle associated PAHs on an annual basis during dry and wet periods are significant due to the high concentrations of contaminants in this size range in both air and rain.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    Hemawan, Kadek W.; Gou, Huiyang; Hemley, Russell J.

    2015-11-01

    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.

  20. 20th century atmospheric deposition and acidification trends in lakes of the Sierra Nevada, California, USA.

    PubMed

    Heard, Andrea M; Sickman, James O; Rose, Neil L; Bennett, Danuta M; Lucero, Delores M; Melack, John M; Curtis, Jason H

    2014-09-01

    We investigated multiple lines of evidence to determine if observed and paleo-reconstructed changes in acid neutralizing capacity (ANC) in Sierra Nevada lakes were the result of changes in 20th century atmospheric deposition. Spheroidal carbonaceous particles (SCPs) (indicator of anthropogenic atmospheric deposition) and biogenic silica and δ(13)C (productivity proxies) in lake sediments, nitrogen and sulfur emission inventories, climate variables, and long-term hydrochemistry records were compared to reconstructed ANC trends in Moat Lake. The initial decline in ANC at Moat Lake occurred between 1920 and 1930, when hydrogen ion deposition was approximately 74 eq ha(-1) yr(-1), and ANC recovered between 1970 and 2005. Reconstructed ANC in Moat Lake was negatively correlated with SCPs and sulfur dioxide emissions (p = 0.031 and p = 0.009). Reconstructed ANC patterns were not correlated with climate, productivity, or nitrogen oxide emissions. Late 20th century recovery of ANC at Moat Lake is supported by increasing ANC and decreasing sulfate in Emerald Lake between 1983 and 2011 (p < 0.0001). We conclude that ANC depletion at Moat and Emerald lakes was principally caused by acid deposition, and recovery in ANC after 1970 can be attributed to the United States Clean Air Act. PMID:25078969

  1. A new dust transport approach to quantify anthropogenic sources of atmospheric PM10 deposition on lakes

    NASA Astrophysics Data System (ADS)

    Weiss, Lee; Thé, Jesse; Gharabaghi, Bahram; Stainsby, Eleanor A.; Winter, Jennifer G.

    2014-10-01

    Windblown dust simulations are one of the most uncertain types of atmospheric transport models. This study presents an integrated PM10 emission, transport and deposition model which has been validated using monitored data. This model characterizes the atmospheric phosphorus load focusing on the major local sources within the Lake Simcoe airshed including paved and unpaved roads, agricultural sources, construction sites and aggregate mining sources. This new approach substantially reduces uncertainty by providing improved estimates of the friction velocities than those developed previously. Modeling improvements were also made by generating and validating an hourly windfield using detailed meteorology, topography and land use data for the study area. The model was used to estimate dust emissions generated in the airshed and to simulate the long-range transport and deposition of PM10 to Lake Simcoe. The deposition results from the model were verified against observed bulk collector phosphorus concentration data for both wet and dry deposition. Bulk collector data from stations situated outside the airshed in a remote, undeveloped area were also compared to determine the background contribution from distant sources.

  2. 20th century atmospheric deposition and acidification trends in lakes of the Sierra Nevada, California, USA.

    PubMed

    Heard, Andrea M; Sickman, James O; Rose, Neil L; Bennett, Danuta M; Lucero, Delores M; Melack, John M; Curtis, Jason H

    2014-09-01

    We investigated multiple lines of evidence to determine if observed and paleo-reconstructed changes in acid neutralizing capacity (ANC) in Sierra Nevada lakes were the result of changes in 20th century atmospheric deposition. Spheroidal carbonaceous particles (SCPs) (indicator of anthropogenic atmospheric deposition) and biogenic silica and δ(13)C (productivity proxies) in lake sediments, nitrogen and sulfur emission inventories, climate variables, and long-term hydrochemistry records were compared to reconstructed ANC trends in Moat Lake. The initial decline in ANC at Moat Lake occurred between 1920 and 1930, when hydrogen ion deposition was approximately 74 eq ha(-1) yr(-1), and ANC recovered between 1970 and 2005. Reconstructed ANC in Moat Lake was negatively correlated with SCPs and sulfur dioxide emissions (p = 0.031 and p = 0.009). Reconstructed ANC patterns were not correlated with climate, productivity, or nitrogen oxide emissions. Late 20th century recovery of ANC at Moat Lake is supported by increasing ANC and decreasing sulfate in Emerald Lake between 1983 and 2011 (p < 0.0001). We conclude that ANC depletion at Moat and Emerald lakes was principally caused by acid deposition, and recovery in ANC after 1970 can be attributed to the United States Clean Air Act.

  3. Deposition velocity of gaseous organic iodine from the atmosphere to rice plants

    SciTech Connect

    Muramatsu, Yasuyuki; Shigeo-Uchida; Sumiya, Misako; Ohmomo, Yoichiro

    1996-11-01

    To obtain parameter values for the assessment of {sup 129}I transfer from the atmosphere to rice, deposition of CH{sub 3}I to rice plants has been studied. The mass normalized deposition velocity (V{sub D}) of CH{sub 3}I for rough (unhulled) rice was 0.00048 cm{sup 3} g{sup {minus}1} s{sup {minus}1}, which is about 1/300 of that of I{sub 2}. Translocation of iodine, deposited as CH{sub 3}I on leaves and stems, to rice grain was negligibly small. Distribution of iodine between hull and inner part of the grain was found to depend also on the chemical forms of atmospheric iodine to be deposited. The ratio of the iodine distribution in a grain exposed to CH{sub 3}I was as follows: rough rice: brown rice (hulled rice):polished rice = 1.0:0.49:0.38. The distribution ratio in polished grains for CH{sub 3}I exposed rice was about 20 times higher than that for I{sub 2}. 22 refs., 1 fig., 6 tabs.

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

    PubMed

    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. PMID:22574853

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

    PubMed

    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.

  6. Limited impact of atmospheric nitrogen deposition on marine productivity due to biogeochemical feedbacks in a global ocean model

    NASA Astrophysics Data System (ADS)

    Somes, Christopher J.; Landolfi, Angela; Koeve, Wolfgang; Oschlies, Andreas

    2016-05-01

    The impact of increasing anthropogenic atmospheric nitrogen deposition on marine biogeochemistry is uncertain. We performed simulations to quantify its effect on nitrogen cycling and marine productivity in a global 3-D ocean biogeochemistry model. Nitrogen fixation provides an efficient feedback by decreasing immediately to deposition, whereas water column denitrification increases more gradually in the slowly expanding oxygen deficient zones. Counterintuitively, nitrogen deposition near oxygen deficient zones causes a net loss of marine nitrogen due to the stoichiometry of denitrification. In our idealized atmospheric deposition simulations that only account for nitrogen cycle perturbations, these combined stabilizing feedbacks largely compensate deposition and suppress the increase in global marine productivity to <2%, in contrast to a simulation that neglects nitrogen cycle feedbacks that predicts an increase of >15%. Our study emphasizes including the dynamic response of nitrogen fixation and denitrification to atmospheric nitrogen deposition to predict future changes of the marine nitrogen cycle and productivity.

  7. Dissolved organic carbon trends resulting from changes in atmospheric deposition chemistry.

    PubMed

    Monteith, Donald T; Stoddard, John L; Evans, Christopher D; de Wit, Heleen A; Forsius, Martin; Høgåsen, Tore; Wilander, Anders; Skjelkvåle, Brit Lisa; Jeffries, Dean S; Vuorenmaa, Jussi; Keller, Bill; Kopácek, Jiri; Vesely, Josef

    2007-11-22

    Several hypotheses have been proposed to explain recent, widespread increases in concentrations of dissolved organic carbon (DOC) in the surface waters of glaciated landscapes across eastern North America and northern and central Europe. Some invoke anthropogenic forcing through mechanisms related to climate change, nitrogen deposition or changes in land use, and by implication suggest that current concentrations and fluxes are without precedent. All of these hypotheses imply that DOC levels will continue to rise, with unpredictable consequences for the global carbon cycle. Alternatively, it has been proposed that DOC concentrations are returning toward pre-industrial levels as a result of a gradual decline in the sulphate content of atmospheric deposition. Here we show, through the assessment of time series data from 522 remote lakes and streams in North America and northern Europe, that rising trends in DOC between 1990 and 2004 can be concisely explained by a simple model based solely on changes in deposition chemistry and catchment acid-sensitivity. We demonstrate that DOC concentrations have increased in proportion to the rates at which atmospherically deposited anthropogenic sulphur and sea salt have declined. We conclude that acid deposition to these ecosystems has been partially buffered by changes in organic acidity and that the rise in DOC is integral to recovery from acidification. Over recent decades, deposition-driven increases in organic matter solubility may have increased the export of DOC to the oceans, a potentially important component of regional carbon balances. The increase in DOC concentrations in these regions appears unrelated to other climatic factors. PMID:18033294

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

  10. Atmospheric deposition of nitrogen at five subtropical forested sites in South China.

    PubMed

    Chen, Xi Yun; Mulder, Jan

    2007-06-01

    Elevated concentrations of reactive nitrogen (N) in precipitation have been reported for many cities in China. Due to increased use of fossil fuels and expansion in agriculture, further increases in deposition of ammonia (NHx) and reactive N oxides (NOy) are predicted. Increased deposition of reactive N is likely to affect N dynamics and N runoff in forest ecosystems. Yet, in China little work has been done to quantify the levels of atmospheric N deposition in such systems. Here, we assess the deposition of inorganic N (ammonium, NH4+ and nitrate, NO3-) for five subtropical forest ecosystems in remote and urban areas of South China. Annual volume-weighted concentrations in bulk precipitation range from 0.18 to 1.55 mg NH4+ -N L(-1) and from 0.12 to 0.74 mg NO3- -N L(-1). These values are large and several times greater than those reported for remote sites of the world. The fluxes of total inorganic N (TIN) in wet-only deposition range from 0.8 to 2.3 g N m(-2) yr(-1), with NH4+ -N contributing 54% to 77%. Both the tree canopy and the ground vegetation layer are important in determining the net N flux reaching the forest floor, but the net effect varies from site to site. At TieShanPing (TSP), close to Chongqing city, and at CaiJiaTang (CJT), near Shaoshan (Hunan province), the canopy represents a net source of N, probably due to dry deposition. At the other three sites (LiuChongGuan (LCG), LeiGongShan (LGS), both in Guizhou province, and LiuXiHe (LXH) in Guangdong), a net loss of reactive N from precipitation water occurs in the canopy, probably due to uptake processes. The total annual atmospheric TIN load is estimated to range from at least 0.8 g N m(-2) yr(-1) to 4.0 g N m(-2) yr(-1), with a considerable contribution from dry deposition. Concentrations and fluxes of inorganic N in tree canopy throughfall are greater than those in North America. Also the contribution of NH4+ -N to TIN fluxes in throughfall (40% to 70%) is greater than in North America. Our sites

  11. Atmospheric volcanic loading derived from bipolar ice cores: Accounting for the spatial distribution of volcanic deposition

    NASA Astrophysics Data System (ADS)

    Gao, Chaochao; Oman, Luke; Robock, Alan; Stenchikov, Georgiy L.

    2007-05-01

    Previous studies have used small numbers of ice core records of past volcanism to represent hemispheric or global radiative forcing from volcanic stratospheric aerosols. With the largest-ever assembly of volcanic ice core records and state-of-the-art climate model simulations of volcanic deposition, we now have a unique opportunity to investigate the effects of spatial variations on sulfate deposition and on estimates of atmospheric loading. We have combined 44 ice core records, 25 from the Arctic and 19 from Antarctica, and Goddard Institute for Space Studies ModelE simulations to study the spatial distribution of volcanic sulfate aerosols in the polar ice sheets. We extracted volcanic deposition signals by applying a high-pass loess filter to the time series and examining peaks that exceed twice the 31-year running median absolute deviation. Our results suggest that the distribution of volcanic sulfate aerosol follows the general precipitation pattern in both regions, indicating the important role precipitation has played in affecting the deposition pattern of volcanic aerosols. We found a similar distribution pattern for sulfate aerosols from the 1783-1784 Laki and 1815 Tambora eruptions, as well as for the total β activity after the 1952-1954 low-latitude Northern Hemisphere and 1961-1962 high-latitude Northern Hemisphere atmospheric nuclear weapon tests. This confirms the previous assumption that the transport and deposition of nuclear bomb test debris resemble those of volcanic aerosols. We compare three techniques for estimating stratospheric aerosol loading from ice core data: radioactive deposition from nuclear bomb tests, Pinatubo sulfate deposition in eight Antarctic ice cores, and climate model simulations of volcanic sulfate transport and deposition following the 1783 Laki, 1815 Tambora, 1912 Katmai, and 1991 Pinatubo eruptions. By applying the above calibration factors to the 44 ice core records, we have estimated the stratospheric sulfate aerosol

  12. Geomorphology and Depositional Subenvironments of Gulf Islands National Seashore, Mississippi

    USGS Publications Warehouse

    Morton, Robert A.; Rogers, Bryan E.

    2010-01-01

    The U.S. Geological Survey (USGS) is studying coastal hazards and coastal change to improve our understanding of coastal ecosystems and to develop better capabilities of predicting future coastal change. One approach to understanding the dynamics of coastal systems is to monitor changes in barrier-island subenvironments through time. This involves examining morphological and topographic change at temporal scales ranging from millennia to years and spatial scales ranging from tens of kilometers to meters. Of particular interest are the processes that produce those changes and the determination of whether or not those processes are likely to persist into the future. In these analyses of hazards and change, both natural and anthropogenic influences are considered. Quantifying past magnitudes and rates of coastal change and knowing the principal factors that govern those changes are critical to predicting what changes are likely to occur under different scenarios, such as short-term impacts of extreme storms or long-term impacts of sea-level rise. Gulf Islands National Seashore was selected for detailed mapping of barrier-island morphology and topography because the islands offer a diversity of depositional subenvironments and the islands' areas and positions have changed substantially in historical time. The geomorphologic and subenvironmental maps emphasize the processes that formed the surficial features and also serve as a basis for documenting which subenvironments are relatively stable, such as the beach ridge complex, and those which are highly dynamic, such as the beach and active overwash zones. The primary mapping procedures used supervised functions within a Geographic Information System (GIS) that classified depositional subenvironments and features (map units) and delineated boundaries of the features (shapefiles). The GIS classified units on the basis of tonal patterns of a feature in contrast to adjacent features observed on georeferenced aerial

  13. THE IMPORTANCE OF EMISSIONS SPECIATION TO THE ATMOSPHERIC TRANSPORT AND DEPOSITION OF MERCURY

    EPA Science Inventory

    The atmospheric pathway of the global mercury cycle is believed to be the main source of mercury contamination to aquatic eco-systems throughout the United States and in most other nations where direct disposal of mercury to water has been largely eliminated. Although the spatia...

  14. Engineering of pulsed laser deposited calcium phosphate biomaterials in controlled atmospheres

    NASA Astrophysics Data System (ADS)

    Drukteinis, Saulius E.

    Synthetic calcium phosphates (CAP) such as hydroxyapatite (HA) have been used as regenerative bone graft materials and also as thin films to improve the integration of biomedical implant devices within skeletal tissue. Pulsed laser deposition (PLD) can deposit crystalline HA with significant adhesion on titanium biomaterials. However, there are PLD processing constraints due to the complex physical and chemical interactions occurring simultaneously during PLD, which influence ablation plume formation and development. In this investigation PLD CAP films were engineered with a focus on novel decoupling of partial pressure of H2O (g) ( PH2O ) from total background pressure, in combination with substrate heat treatment and laser energy density control. Characterization of these films was performed with X-ray Diffraction, Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, Fourier Transform Infrared Spectroscopy, and Optical Profilometry. In vitro cellular adhesion testing was also performed using osteoblast (MC3T3) cell lines to evaluate adhesion of bone-forming cells on processed PLD CAP samples. Preferred a-axis orientation films were deposited in H2O (g) saturated atmospheres with reduced laser fluence (< 4 J/cm2). Crystalline HA/tetracalcium phosphate (TTCP) films were deposited in H2O ( g)-deficient atmospheres with higher laser fluence (> 3 J/cm 2). Varied PH2O resulted in control of biphasic HA/TTCP composition with increasing TTCP at lower PH2O . These were dense continuous films composed of micron-scale particles. Cellular adhesion assays did not demonstrate a significant difference between osteoblast adhesion density on HA films compared with biphasic HA/TTCP films. Room temperature PLD at varied PH2O combined with furnace heat treatment resulted in controlled variation in surface amplitude parameters including surface roughness (S a), root mean square (Sq), peak to valley height (St), and ten-point height ( Sz). These discontinuous films were

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

    NASA Astrophysics Data System (ADS)

    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.

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

    USGS Publications Warehouse

    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 (<50 km) and remote from (>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.

  17. Chain Assemblies from Nanoparticles Synthesized by Atmospheric Pressure Plasma Enhanced Chemical Vapor Deposition: The Computational View.

    PubMed

    Mishin, Maxim V; Zamotin, Kirill Y; Protopopova, Vera S; Alexandrov, Sergey E

    2015-12-01

    This article refers to the computational study of nanoparticle self-organization on the solid-state substrate surface with consideration of the experimental results, when nanoparticles were synthesised during atmospheric pressure plasma enhanced chemical vapor deposition (AP-PECVD). The experimental study of silicon dioxide nanoparticle synthesis by AP-PECVD demonstrated that all deposit volume consists of tangled chains of nanoparticles. In certain cases, micron-sized fractals are formed from tangled chains due to deposit rearrangement. This work is focused on the study of tangled chain formation only. In order to reveal their formation mechanism, a physico-mathematical model was developed. The suggested model was based on the motion equation solution for charged and neutral nanoparticles in the potential fields with the use of the empirical interaction potentials. In addition, the computational simulation was carried out based on the suggested model. As a result, the influence of such experimental parameters as deposition duration, particle charge, gas flow velocity, and angle of gas flow was found. It was demonstrated that electrical charges carried by nanoparticles from the discharge area are not responsible for the formation of tangled chains from nanoparticles, whereas nanoparticle kinetic energy plays a crucial role in deposit morphology and density. The computational results were consistent with experimental results. PMID:26682441

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

    NASA Astrophysics Data System (ADS)

    Cherin, N.; Roustan, Y.; Musson-Genon, L.; Seigneur, C.

    2014-12-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Cherin, N.; Roustan, Y.; Musson-Genon, L.; Seigneur, C.

    2015-03-01

    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.

  20. Influence of variable rates of neritic carbonate deposition on atmospheric carbon dioxide and pelagic sediments

    NASA Technical Reports Server (NTRS)

    Walker, J. C.; Opdyke, B. C.

    1995-01-01

    Short-term imbalances in the global cycle of shallow water calcium carbonate deposition and dissolution may be responsible for much of the observed Pleistocene change in atmospheric carbon dioxide content. However, any proposed changes in the alkalinity balance of the ocean must be reconciled with the sedimentary record of deep-sea carbonates. The possible magnitude of the effect of shallow water carbonate deposition on the dissolution of pelagic carbonate can be tested using numerical simulations of the global carbon cycle. Boundary conditions can be defined by using extant shallow water carbonate accumulation data and pelagic carbonate deposition/dissolution data. On timescales of thousands of years carbonate deposition versus dissolution is rarely out of equilibrium by more than 1.5 x 10(13) mole yr-1. Results indicate that the carbonate chemistry of the ocean is rarely at equilibrium on timescales less than 10 ka. This disequilibrium is probably due to sea level-induced changes in shallow water calcium carbonate deposition/dissolution, an interpretation that does not conflict with pelagic sedimentary data from the central Pacific.

  1. Using stable and radioactive isotopes to trace atmospherically deposited Pb in montane forest soils.

    PubMed

    Kaste, James M; Friedland, Andrew J; Stürup, Stefan

    2003-08-15

    Atmospheric deposition of lead (Pb) throughout the 1900s resulted in elevated amounts of this toxic metal even in remote forest soils of the northeastern United States. Soils can act as a net sink for metals and thus minimize groundwater and surface water contamination. Recent studies utilizing forest floor temporal data and models of total Pb in precipitation, surface soils, and streams have estimated the time scale of Pb release from soils. However, due to the limited availability and spatial variability of forest floor survey data, other methods for quantifying anthropogenic Pb movement are needed. This study uses the isotopic composition (206Pb/207Pb) of soil Pb and measurements of 210Pb and 226Ra to directly trace the transit of atmospherically deposited Pb in the soil profile. We also report on the recovery of an enriched 207Pb dose applied in 1984 to the surface of a soil plot in the coniferous forest at Camels Hump in Vermont. The isotopic composition of soil Pb in low elevation deciduous forests suggests that approximately 65% of the original atmospheric Pb load has migrated from the forest floor to the upper 10 cm of the mineral soil. Higher elevation sites with coniferous vegetation have thicker forest floors, which have prevented significant amounts of Pb from entering the mineral soil. After 17 years, the soil organic horizon in the coniferous zone prevented any penetration of the applied Pb into the mineral soil. Using 210Pb budgets in different soil compartments, we determine forest floor response times for atmospherically delivered Pb to be approximately 60 years in the low elevation deciduous forest zone and 150 years for the high elevation spruce-fir forest zone at Camels Hump. According to its distribution in the soil profile, we conclude that a dispersed release of anthropogenic Pb to groundwater and surface water is possible this century. Our results also offer independent confirmation of Pb deposition models previously generated for the region.

  2. The effects of atmospheric nitrogen deposition in the Rocky Mountains of Colorado and southern Wyoming, USA-a critical review.

    PubMed

    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(-1) yr(-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(3)(-) 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. PMID:14568725

  3. Low temperature atmospheric pressure chemical vapor deposition of group 14 oxide films

    SciTech Connect

    Hoffman, D.M.; Atagi, L.M. |; Chu, Wei-Kan; Liu, Jia-Rui; Zheng, Zongshuang; Rubiano, R.R.; Springer, R.W.; Smith, D.C.

    1994-06-01

    Depositions of high quality SiO{sub 2} and SnO{sub 2} films from the reaction of homoleptic amido precursors M(NMe{sub 2})4 (M = Si,Sn) and oxygen were carried out in an atmospheric pressure chemical vapor deposition r. The films were deposited on silicon, glass and quartz substrates at temperatures of 250 to 450C. The silicon dioxide films are stoichiometric (O/Si = 2.0) with less than 0.2 atom % C and 0.3 atom % N and have hydrogen contents of 9 {plus_minus} 5 atom %. They are deposited with growth rates from 380 to 900 {angstrom}/min. The refractive indexes of the SiO{sub 2} films are 1.46, and infrared spectra show a possible Si-OH peak at 950 cm{sup {minus}1}. X-Ray diffraction studies reveal that the SiO{sub 2} film deposited at 350C is amorphous. The tin oxide films are stoichiometric (O/Sn = 2.0) and contain less than 0.8 atom % carbon, and 0.3 atom % N. No hydrogen was detected by elastic recoil spectroscopy. The band gap for the SnO{sub 2} films, as estimated from transmission spectra, is 3.9 eV. The resistivities of the tin oxide films are in the range 10{sup {minus}2} to 10{sup {minus}3} {Omega}cm and do not vary significantly with deposition temperature. The tin oxide film deposited at 350C is cassitterite with some (101) orientation.

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

    NASA Astrophysics Data System (ADS)

    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

  5. The Soil Chemical Response to Decreases in Atmospheric Sulfate deposition Across the Northeastern United States

    NASA Astrophysics Data System (ADS)

    McHale, M. R.; Siemion, J.; Lawrence, G. B.; Mast, A.

    2012-12-01

    Data from National Atmospheric Deposition (NADP) stations show that since implementation of the Clean Air Act Amendments of 1990 there has been a steady decline in sulfate and nitrate concentrations in precipitation across the northeastern United States. Those decreases have become more pronounced during the last 10 years. There have also been decreasing trends in sulfate and less so nitrate stream-water concentrations during the same period at 3 U.S. Geological Survey Hydrologic Benchmark Network stream gaging stations. These stations are co-located with NADP stations in western Pennsylvania (Young Woman's Creek, YWC), the Catskill Mountains of New York (Neversink River, NR), and in northwestern Maine (Wild River, WR). Precipitation was most acidic at YWC (mean pH in 2010 of 4.68 at YWC, 4.88 at NR, and 4.97 at WR) while stream water was most acidic at WR (mean pH from 1999 to 2010 of 6.08 at WR, 6.19 at NR, and 6.72 at YWC). Soil samples were collected at each site in 2001 and again 10 years later in 2011 in the A and upper B-horizons at two to three locations in each watershed, at an upslope location, a mid-slope location, and in the case of NR also at a lower slope location. Replicate samples were collected from 5 pits at each site. At YWC the site with the lowest precipitation pH and the highest stream-water pH there were clear changes in soil acidity during the last 10 years. There was a decrease in soil pH of 0.7 pH units in the A-horizon of ridge top soils and 0.2 pH units in the mid slope soils while pH increased a mean of 0.2 pH units at both locations in the B-horizon. At NR, the site with intermediate precipitation and stream-water pH, there was a general decrease in soil pH in the A-horizon at the ridge top, mid slope, and lower slope locations although those changes were not as pronounced as those from YWC. Although B-horizon soil pH increased at the ridge top site in NR there were no clear changes in acidity of the mid or lower slope locations. At

  6. Atmospheric dispersion and deposition of iodine-131 released from the Hanford Site

    SciTech Connect

    Ramsdell, J.V.; Simonen, C.A.; Burk, K.W.; Stage, S.A.

    1994-06-01

    Approximately 2.6x10{sup 4} TBq (700,000 curies) of iodine-131 were released to the air from reactor fuel processing plants on the Hanford Site in southcentral Washington State from December 1944 through December 1949. The Hanford Environmental Dose Reconstruction (HEDR) Project developed a suite of codes to estimate the doses that might have resulted from these releases. The Regional Atmospheric Transport Code for Hanford Emission Tracking (RATCHET) computer code is part of this suite. The RATCHET code implements a Lagrangian-trajectory, Gaussian-puff dispersion model that uses hourly meteorological and release rate data to estimate daily time-integrated air concentrations and surface contamination for use in dose estimates. In this model, iodine is treated as a mixture of three species (nominally, inorganic gases, organic gases, and particles). Model deposition parameters are functions of the mixture and meteorological conditions. A resistance model is used to calculate dry deposition velocities. Equilibrium between concentrations in the precipitation and the air near the ground is assumed in calculating wet deposition of gases, and irreversible washout of the particles is assumed. RATCHET explicitly treats the uncertainties in model parameters and meteorological conditions. Uncertainties in iodine-131 release rates and partitioning among the nominal species are treated by varying model input. The results of 100 model runs for December 1944 through December 1949 indicate that monthly average air concentrations and deposition have uncertainties ranging from a factor of two near the center of the time-integrated plume to more than an order of magnitude near the edge. These results indicate that -10% of the iodine-131 released to the atmosphere decayed during transit in the study area, -56% was deposited within the study area, and the remaining 34% was transported out of the study area while still in the air.

  7. Geochemistry of the Nsuta Mn deposit in Ghana: Implications for the Paleoproterozoic atmosphere and ocean chemistry

    NASA Astrophysics Data System (ADS)

    Goto, K. T.; Ito, T.; Suzuki, K.; Kashiwabara, T.; Takaya, Y.; Shimoda, G.; Nozaki, T.; Kiyokawa, S.; Tetteh, G. M.; Nyame, F. K.

    2013-12-01

    Oxygenation of the atmosphere and oceans has influenced the evolution of ocean chemistry and diversification of early life. A number of large manganese (Mn) deposits are distributed in the Paleoproterozoic sedimentary successions that were formed during the great oxidation event (GOE) around 2.4-2.2 Ga (Meynard, 2010). Due to the high redox potential of Mn, occurrences of Mn deposits have been regarded as important evidence for a highly oxidized environment during the Paleoproterozoic (Kirschvink et al., 2000). Furthermore, because Mn oxides strongly adsorb various elements, including bioessential elements such as Mo, formation of large Mn deposits may have affected the seawater chemical composition and ecology during the Paleoproterozoic. However, the genesis of each Mn deposit is poorly constrained, and the relationships among the formation of Mn deposits, the evolution of atmospheric and ocean chemistry, and the diversification of early life are still ambiguous. In this study, we report the Re-Os isotope compositions, rare earth element (REE) compositions, and abundance of manganophile elements in the Mn carbonate ore and host sedimentary rock samples collected from the Nsuta Mn deposit of the Birimian Supergroup, Ghana. The Nsuta deposit is one of the largest Paleoproterozoic Mn deposits, although its genesis remains controversial (Melcher et al., 1995; Mucke et al., 1999). The composite Re-Os isochron age (2149 × 130 Ma) of the Mn carbonate and sedimentary rock samples was consistent with the depositional age of the sedimentary rocks (~2.2 Ga) presumed from the U-Pb zircon age of volcanic rocks (Hirdes and Davis, 1998), suggesting that the timing of Mn ore deposition was almost equivalent to the host rock sedimentation. The PAAS-normalized REE pattern showed a positive Eu anomaly in all samples and a positive Ce anomaly only in the Mn carbonate ore. These REE patterns indicate the possible contribution of Eu-enriched fluids derived from hydrothermal activity

  8. Spatial Patterns of Atmospherically Deposited Organic Contaminants at High Elevation in the Southern Sierra Nevada Mountains, California

    EPA Science Inventory

    Atmospherically deposited contaminants in the Sierra Nevada mountains of California have been implicated as adversely affecting amphibians and fish, yet the distributions of contaminants within the mountains are poorly known, particularly at high elevation. We tested the hypothe...

  9. Spatial Patterns of Atmospherically Deposited Organic Contaminants at High Elevation in the Southern Sierra Nevada Mountains, California

    EPA Science Inventory

    Atmospherically deposited contaminants in the Sierra Nevada mountains of California have been implicated as a factor adversely affecting biological resources such as amphibians and fish, yet the distributions of contaminants within the mountains are poorly known, particularly at...

  10. Application of Ecosystem-Scale Fate and Bioaccumulation Models to Predict Fish Mercury Response Times to Changes in Atmospheric Deposition

    EPA Science Inventory

    Management strategies for controlling anthropogenic mercury emissions require understanding how ecosystems will respond to changes in atmospheric mercury deposition. Process-based mathematical models are valuable tools for informing such decisions, because measurement data often ...

  11. Size-dependent atmospheric deposition and inhalation exposure of particle-bound organophosphate flame retardants.

    PubMed

    Luo, Pei; Bao, Lian-Jun; Guo, Ying; Li, Shao-Meng; Zeng, Eddy Y

    2016-01-15

    Atmospheric size-fractionated particles were collected at different heights in an e-waste recycling zone (QY) and urban Guangzhou (GZ), China and analyzed for organophosphate flame retardants (OPFRs). The total air concentrations of eight OPFRs were 130±130 and 138±127 ng m(-3) in QY and GZ, respectively. Compositional profiles of chlorinated OPFRs were different between QY and GZ, but the size distribution patterns of all OPFRs were not significantly different at different heights. Estimated atmospheric deposition fluxes of OPFRs were 51±67 and 55±13 μg m(-2) d(-1) in QY and GZ, respectively, and the coarse particles (Dp>1.8 μm) dominated both the dry and wet deposition fluxes. Moreover, not all particle-bound OPFRs were inhalable and deposited in the human respiratory tract. The calculated inhalation doses of OPFRs were much lower than the reference doses, suggesting that potential health risk due to inhalation exposure to particle-bound OPFRs in the e-waste recycling zone and urban site was low.

  12. Year-round grazing to counteract effects of atmospheric nitrogen deposition may aggravate these effects.

    PubMed

    van Dobben, H F; Wamelink, G W W; Klimkowska, A; Slim, P A; van Til, M

    2014-12-01

    Excessive nitrogen input in natural ecosystems is a major threat to biodiversity. A coastal dune area near Amsterdam in the Netherlands suffers from high atmospheric nitrogen deposition affecting sensitive habitats such as fixed coastal dunes with herbaceous vegetation ('grey dunes'). To mitigate its effect year round grazing was applied from 2007 until 2012. In winter, when natural food supply is low, the cattle received supplementary hay that caused additional inputs of nitrogen. Estimates based on nitrogen contents of hay, as well as of manure, showed the input through winter feeding (c. 3-14 kg N ha(-1).y(-1)) is in the same order of magnitude as both the actual deposition (c. 17 kg N ha(-1).y(-1)) and the critical load for a number of herbaceous habitat types (10-15 kg N ha(-1).y(-1)). Locally, the effect of winter feeding adds to the effect of nitrogen redistribution within the area caused by the cattle's terrain usage. We conclude that winter feeding may aggravate effects of atmospheric nitrogen deposition.

  13. [Wet deposition of atmospheric nitrogen of the Jinshui watershed in the upper Hanjiang River].

    PubMed

    Wang, Jin-Jie; Zhang, Ke-Rong; Wu, Chuan; Zhang, Quan-Fa

    2014-01-01

    The Jinshui River, a tributary of the Hanjiang River, is an important region of water conservation for the Middle Route of South to North Water Transfer Project. However, water quality has been deteriorated in recent years, in particular nitrogen increasing pollution. In this study, the wet deposition of atmospheric nitrogen in the Jinshui watershed was investigated between Feb. 2012-Feb. 2013, and the corresponding contribution to the river N loading was calculated using N retention model. The results indicated that the volume-weighted concentration of dissolved total nitrogen (DTN) was 0.24-2.89 mg x L(-1), consisting of ammonium (NH(4+)-N) (42.8%), nitrate (NO3- N) (13.3%) and dissolved organic nitrogen (DON) (43.9%), which decreased with rainfall volume as a result of dilution. The wet deposition of atmospheric N was mainly from anthropogenic pollution and the flux was between 4.97-7.00 kg x (hm2 x a)(-1), dominated by seasonal rainfall, of which about 81% occurred in spring and summer and the flux in a decreasing order of upstream, downstream, and middlestream. The wet deposition contributed approximately 34,000-46,000 kg N to the river, accounting for only 5.05%-6.78% of the contribution by fertilizers, which was too small to be the main source of the river N loading. PMID:24720187

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

    USGS Publications Warehouse

    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.

  15. Dry deposition, concentration and gas/particle partitioning of atmospheric carbazole

    NASA Astrophysics Data System (ADS)

    Esen, Fatma; Tasdemir, Yücel; Cindoruk, S. Sıddık

    2010-03-01

    The atmospheric concentrations and dry deposition of carbazole were measured to present the temporal changes, gas/particle partitioning and magnitude of fluxes. Atmospheric samples were collected from July 2004 to May 2005 at four different sites in Bursa, Turkey. The average total (gas and particulate) carbazole concentrations were 7.6 ± 9.9 ng m - 3 in Gulbahce (Residential), 1.1 ± 1.2 ng m - 3 in BUTAL (Traffic), 3.3 ± 5.0 ng m - 3 in BOID (Industrial), and 1.2 ± 0.7 ng m - 3 in the Uludag University Campus (UU) (Suburban). Experimental gas/particle partition coefficient ( Kp) was determined using the study results and compared with Kp values calculated from octanol-air and soot-air + octanol partitioning models. Total dry deposition fluxes of carbazole were 290 ± 484 ng m - 2 d - 1 in BUTAL and 72 ± 67 ng m - 2 d - 1 in the UU Campus. Particulate phase dry deposition velocities were 0.81 ± 0.78 cm s - 1 and 0.90 ± 1.53 cm s - 1 for BUTAL and the UU Campus, respectively. On the other hand, gas-phase mass transfer coefficients were calculated to be 0.34 ± 0.29 cm s - 1 and 0.26 ± 0.17 cm s - 1 for BUTAL and the UU Campus, respectively.

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

    PubMed

    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

  17. Contribution of atmospheric depositi