Environ. Sci. Technol. 2010, 44, 1587–1593
Aeolian Contamination of Se and Ag in the North Pacific from Asian Fossil Fuel Combustion M A R A A . R A N V I L L E , * ,†,# GREGORY A. CUTTER,‡ C L I F T O N S . B U C K , §,¶ WILLIAM M. LANDING,§ L Y N D A S . C U T T E R , ‡, JOSEPH A. RESING,| AND A. RUSSELL FLEGAL⊥ WIGS laboratory, Department of Microbiology and Environmental Toxicology, 430 Physical Sciences Building, 1156 High Street, University of California-Santa Cruz, Santa Cruz, California 95064, Department of Ocean, Earth, and Atmospheric Sciences, 4500 Elkhorn Avenue, Old Dominion University, Norfolk, Virginia 23529-0276, Department of Oceanography, Rm 325 OSB, Florida State University, Tallahassee, Florida 32306-4320, Joint Institute for the Study of the Atmosphere and the Oceans, NOAA-Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Bldg. 3, Bin C15700, Seattle, Washington 98115-0070, and WIGS laboratory, Institute of Marine Science, 446 Physical Sciences Building, 1156 High Street, University of California-Santa Cruz, Santa Cruz, California 95064
Received September 14, 2009. Revised manuscript received December 23, 2009. Accepted December 30, 2009.
Energy production from fossil fuels, and in particular the burning of coal in China, creates atmospheric contamination that is transported across the remote North Pacific with prevailing westerly winds. In recent years this pollution from within Asia has increased dramatically, as a consequence of vigorous economic growth and corresponding energy consumption. During the fourth Intergovernmental Oceanographic Commission baseline contaminant survey in the western Pacific Ocean from May to June, 2002, surface waters and aerosol samples were measured to investigate whether atmospheric deposition of trace elements to the surface North Pacific was altering trace element biogeochemical cycling. Results show a presumably anthropogenic enrichment of Ag and of Se, which is a known tracer of coal combustion, in the North Pacific atmosphere and surface waters. Additionally, a strong correlation was seen between dissolved Ag and Se concentrations in surface waters. This suggests that Ag should now also be considered a geochemical tracer for coal combustion, and provides * Corresponding author e-mail:
[email protected]. † Department of Microbiology and Environmental Toxicology, University of California-Santa Cruz. ‡ Old Dominion University. § Florida State University. | NOAA-Pacific Marine Environmental Laboratory. ⊥ Institute of Marine Science, University of California-Santa Cruz. # Current address: Bard Center for Environmental Policy, Bard College, 30 Campus Road, Annandale-on-Hudson, NY, 12504. ¶ Current address: Department of Ocean Sciences, University of California-Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064. Department of Biological Sciences, Marine Environmental Biology, 3616 Trousdale Parkway, ACB 401, University of Southern California, Los Angeles, CA, 90089-0371. 10.1021/es902523m
2010 American Chemical Society
Published on Web 02/02/2010
further evidence that Ag exhibits a disturbed biogeochemical cycle as the result of atmospheric deposition to the North Pacific.
Introduction Industrial emissions and biomass burning in mainland Asia combine with naturally occurring dust storms to create atmospheric pollution that contains contaminants such as NOx, SOx, and O3, along with potentially toxic trace elements such as Hg (1-6). Mineral aerosols (continental dust) are a source of crustal elements such as Fe, Al, and Ti (7) to this pollution, while industry, and more importantly, the burning of fossil fuels, contributes enriched levels of trace elements like Se (8). In China, coal combustion is the primary source of energy for the industrial sector and power generation (9, 10), and coal consumption in China is predicted to increase by 3.0% every year until 2030 (9). Although emission controls on coal-fired power plants are increasingly common (11, 12), they still are of limited effectiveness (13). Prevailing westerly winds carry this atmospheric pollution eastward from Asia over the North Pacific Ocean, where it can be deposited in surface waters (14). This commonly occurs in the spring and early summer, when several arid or semiarid regions in China contribute dust to the atmosphere during severe storms (e.g., refs 15 and 16). The aerosols can be carried as far as North America (e.g., refs 17-19); preliminary studies have identified Asian Hg fluxes on the coast of California (20), and while under certain meteorological conditions, Asian dust has been carried all the way to the western coast of North America in a remarkably short period of time (
