Emissions and long-range transport of toxic metals and metalloids pose a global threat to ecosystems and human health. Global industrialization occurring from the late nineteenth century releases large quantities of pollutants into the Earth’s atmosphere. Despite international efforts to mitigate emissions, accumulation of metals is still observed in the most remote regions of the planet. New baseline studies are needed to determine (i) natural background concentration of pollutants, (ii) contributions of anthropogenic emissions, and (iii) potential remobilization of previously deposited metals. Constructing such records requires distinguishing source strength from transport efficiency to the recording site and accounting for local depositional effects. Here we investigate the sensitivity and representation of Southern Hemisphere atmospheric concentrations of heavy metals (Fe, Al, Mn, Pb, Tl, and As) in the Roosevelt Island Climate Evolution (RICE) ice core, a new coastal Antarctic ice core site. Concentration variability with precipitation is explored in daily surface snow samples collected over 70 days, while seasonal deposition is investigated through snow pit sampling. We find that snow sample concentrations increase with particular snow precipitation types (rime and fog) and enhanced meridional atmospheric transport to the site. Snow pit heavy metals peak in summer and also show variable intraannual peaks. Seasonal airmass modeling based on ERA Interim reanalysis data indicates a synoptic shift during the spring and summer months. We conclude that modern heavy metal concentrations are influenced by transport efficiency and scavenging behavior; and thus, time series records from RICE have the potential to provide representative data of regional changes in heavy metals.
Bibliographical noteFunding Information:
This work is a contribution to the Roosevelt Island Climate Evolution (RICE) Program, funded by national contributions from New Zealand, Australia, Denmark, Germany, Italy, the People’s Republic of China, Sweden, United Kingdom, and the United States of America. The main logistic support was provided by Antarctica New Zealand (K049) and the U.S. Antarctic Program. This work has been funded by the New Zealand Ministry of Business, Innovation, and Employment (grants RDF-VUW-1103 and 540GCT32), Victoria University and GNS Science. The U.S. portion of this research was supported by NSF grant ANT-1042883. We also acknowledge the ECMWF for providing access to the ERA Interim reanalysis data and NOAA/ARL for converting the ERA Interim meteorological data to a HySPLIT compatible format. All data presented in this paper will be uploaded at publication to the NOAA National Climatic Data Centre http://www.ncdc. noaa.gov/data-access/paleoclimatology-data/. Prior to this, any requests for access can be directed to the lead author at email@example.com.
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