References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-10-8617-2010

Assessing the trends and effects of environmental parameters on the behaviour of mercury in the lower atmosphere over cropped land over four seasons

Baya

A. P.

¹ Van Heyst

School of Engineering, University of Guelph, Guelph, ON, Canada

15 09 2010

10 17 8617 8628

This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

This article is available from http://www.atmos-chem-phys.net/10/8617/2010/acp-10-8617-2010.html

The full text article is available as a PDF file from http://www.atmos-chem-phys.net/10/8617/2010/acp-10-8617-2010.pdf

Mercury is released to the atmosphere from natural and anthropogenic sources. Due to its persistence in the atmosphere, mercury is subject to long range transport and is thus a pollutant of global concern. Mercury emitted to the atmosphere enters terrestrial and aquatic ecosystems which act as sinks but also as sources of previously emitted and deposited mercury when the accumulated mercury is emitted back to the atmosphere. Studying the factors and processes that influence the behaviour of mercury from terrestrial sources is thus important for a better understanding of the role of natural ecosystems in the mercury cycling and emission budget. A study was conducted over ten months (November 2006 to August 2007) at Elora, Ontario, Canada to measure gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and particulate bound mercury (HgP) as well as GEM fluxes over different ground cover spanning the four seasons typical of a temperate climate zone. GEM concentrations were measured using a mercury vapour analyzer (Tekran 2537A) while RGM and HgP were measured with the Tekran 1130/1135 speciation unit coupled to another mercury vapour analyzer. A micrometeorological approach was used for GEM flux determination using a continuous two-level sampling system for GEM concentration gradient measurement above the soil surface and crop canopy. The turbulent transfer coefficients were derived from meteorological parameters measured on site. A net GEM volatilization (6.31 ± 33.98 ng mM−2 hr−1, study average) to the atmosphere was observed. Average GEM concentrations and GEM fluxes showed significant seasonal differences and distinct diurnal patterns while no trends were observed for HgP or RGM. Highest GEM concentrations, recorded in late spring and fall, were due to meteorological changes such as increases in net radiation and air temperature in spring and lower atmospheric mixing height in fall. Highest GEM fluxes (18.1 ng m−2 hr−1, monthly average) were recorded in late spring but also during specific events in winter and fall. The main factors influencing the GEM flux were soil moisture content, soil temperature, precipitation events and ground cover. These trends indicate that the soil surface could be a significant mercury source in spring and summer seasons but also under specific meteorological conditions during the winter and fall.

References 1

% vor jede Referenz Cobbett, F. D., Steffen, A., Lawson, G., and Van Heyst, B. J.: GEM fluxes and atmospheric mercury concentrations (GEM, RGM and Hgp) in the Canadian Arctic at Alert, Nunavut, Canada (February–June 2005), Atmos. Environ., in press, 2007.

Cobbett, F. D. and Van Heyst, B. J.: Measurements of GEM fluxes and atmospheric mercury concentrations (GEM, RGM and Hgp) from an agricultural field amended with biosolids in Southern Ont., Canada (October 2004–November 2004), Atmos. Environ., 41(31), 6527–6543, 2007.

Cobos, D. R., Baker, J. M., and Nater, E. A.: Conditional sampling for measuring mercury vapor fluxes, Atmos. Environ., 36(27), 4309–4321, 2002.

Ebinghaus, R., Kock, H., and Schmolke, S.: Measurements of atmospheric mercury with high time resolution: Recent applications in environmental research and monitoring, Fresenius' J. Anal. Chem., 371(6), 806–815, 2001.

Edwards, G. C., Rasmussen, P. E., Schroeder, W. H., Wallace, D. M., Halfpenny-Mitchell, L., Dias, G. M., Kemp, R. J., and Ausma, S.: Development and evaluation of a sampling system to determine gaseous Mercury fluxes using an aerodynamic micrometeorological gradient method, J. Geophys. Res., 110, D10306, doi:10.1029/2004JD005187, 2005.

Engle, M. A., Gustin, M. S., and Zhang, H.: Quantifying natural source mercury emissions from the Ivanhoe Mining District, north-central Nevada, USA, Atmos. Environ., 35(23), 3987–3997, 2001.

Environment Canada: National climate archives, available online at: http://www.climate.weatheroffice.ec.gc.ca, last access: October 2007.

Fitzgerald, W. F.: Is mercury increasing in the atmosphere? The need for an atmospheric mercury network (AMNET), Water Air Soil Pollut., 80(1), 245–254, 1995.

Fritsche, J., Obrist, D., Zeeman, M., Conen, F., Eugster, W., and Alewell, C.: Elemental mercury fluxes over a sub-alpine grassland determined with two micrometeorological methods, Atmos. Environ., 42(13), 2922–2933, 2008.

Gustin, M. S., Taylor, G. E., and Taylor, R.: Effect of temperature and air movement on the flux of elemental mercury from substrate to the atmosphere, J. Geophys. Res., 102(D3), 3891–3898, 1997.

Gustin, M. S.: Are mercury emissions from geologic sources significant? A status report, Sci. Total Environ., 304(1–3), 153–167, 2003.

Iverfeldt, Å. and Lindqvist, O.: Atmospheric oxidation of elemental mercury by ozone in the aqueous phase, Atmos. Environ., 20(8), 1567–1573, 1986.

Landis, M. S., Stevens, R. K., Schaedlich, F., and Prestbo, E. M.: Development and Characterization of an Annular Denuder Methodology for the Measurement of Divalent Inorganic Reactive Gaseous Mercury in Ambient Air, American Chemical Society, Easton, Pa, 2002.

Lin, C. and Pehkonen, S. O.: The chemistry of atmospheric mercury: a review, Atmos. Environ., 33(13), 2067–2079, 1999.

Lindberg, S., Bullock, R., Ebinghaus, R., Engstrom, D., Feng, X., Fitzgerald, W., Pirrone, N., Prestbo, E., and Seigneur, C.: A Synthesis of Progress and Uncertainties in Attributing the Sources of Mercury in Deposition, Ambio, 36(1), 19–32, 2007.

Lindberg, S. E., Kim, Ki-Hyun, Meyers, T. P., and Owens, J. G.: Micrometeorological Gradient Approach for Quantifying Air/Surface Exchange of Mercury Vapor: Tests Over Contaminated Soils, American Chemical Society, Easton, Pa, 1995.

Lynam, M. M. and Keeler, G. J.: Automated Speciated Mercury Measurements in Michigan, Environ. Sci. Technol., 39(23), 9253–9262, 2005.

Mason, R. P., Fitzgerald, W. F., and Morel, F. M. M.: The biogeochemical cycling of elemental mercury: anthropogenic influences, Pergamon Press., Oxford, 1994.

Mason, R. P. and Sheu, G.-R.: Role of the ocean in the global mercury cycle, Global Biogeochem. Cy., 16(4), 1093, doi:10.1029/2001GB001440, 2002.

Munthe, J.: Aqueous Oxidation of Elemental Mercury by Ozone. Atmospheric Enviro. A, 26, 1461–1468, doi:10.1016/0960-1686(92)90131-4, 1992.

Obrist, D., Gustin, M. S., Arnone III, J. A., Johnson, D. W., Schorran, D. E., and Verburg, P. S. J.: Measurements of gaseous elemental mercury fluxes over intact tallgrass prairie monoliths during one full year, Atmos. Environ., 39(5), 957–965, 2005.

Poissant, L., Pilote, M., and Casimir, A.: Mercury flux measurements in a naturally enriched area: Correlation with environmental conditions during the Nevada Study and Tests of the Release of Mercury From Soils (STORMS), J. Geophys. Res., 104(D17), 845–858, 1999.

Poissant, L., Pilote, M., Beauvais, C., Constant, P., and Zhang, H. 2005: A year of continuous measurements of three atmospheric mercury species (GEM, RGM and Hgp) in southern Québec, Canada, Atmos. Environ., 39(7), 1275–1287, 2005.

Satoh, H.: Occupational and Environmental Toxicology of Mercury and Its Compounds, Industrial Health-Kawasaki, 38(2), 153–164, 2000.

Schroeder, W. H. and Munthe, J.: Atmospheric mercury–An overview, Atmos. Environ., 32(5), 809–822, 1998.

Seigneur, C., Vijayaraghavan, K., Lohman, K., Karamchandani, P., and Scott, C.: Global Source Attribution for Mercury Deposition in the United States, Environ. Sci. Technol., 38(2), 555–569, 2004.

Song, X. and Van Heyst, B.: Volatilization of mercury from soils in response to simulated precipitation, Atmos. Environ., 39(39), 7494–7505, 2005.

Valente, R. J., Shea, C., Lynn Humes, K., and Tanner, R. L.: Atmospheric mercury in the Great Smoky Mountains compared to regional and global levels, Atmos. Environ., 41(9), 1861–1873, 2007.

Yatavelli, R. L. N., Fahrni, J. K., Kim, M., Crist, K. C., Vickers, C. D., Winter, S. E., and Connell, D. P.: Mercury, PM2.5 and gaseous co-pollutants in the Ohio River Valley region: Preliminary results from the Athens supersite, Atmos. Environ., 40(34), 6650–6665, 2006.

Zhang, H., Lindberg, S. E., Marsik, F. J., and Keeler, G. J.: Mercury Air/Surface exchange kinetics of background soils of the tahquamenon river watershed in the michigan upper peninsula, Water Air Soil Pollut., 126, 151–169, 2001.