Abstract
To study the long-range transport of atmospheric pollutants from lower latitude industrial areas to the Arctic, we analysed a peat core spanning the last ~700 cal. yr (~AD 1300-2000) from southern Greenland, an area sensitive to atmospheric pollution from North American and Eurasian sources. A previous investigation conducted in the same location recorded atmospheric lead (Pb) pollution after ~1845, with peak values recorded in the 1970s, and concluded that a North American source was most likely. To confirm the origin of the lead, we present new Pb isotope data from Sandhavn, together with a high-resolution record for mercury (Hg) deposition. Results demonstrate that the mercury accumulation rate has steadily increased since the beginning of the 19th century, with maximum values of 9.3 μg m-2 yr-1 46 recorded ∼1940. Lead isotopic ratios show two mixing lines: one which represents inputs from local and regional geogenic sources, and another that comprises regional geogenic and pollution sources. Detrending the Pb isotopic ratio record (thereby extracting the effect of the geogenic mixing) has enabled us to reconstruct a detailed chronology of metal pollution. The first sustained decrease in Pb isotope signals is recorded as beginning ~1740-1780 with the lowest values (indicating the highest pollution signature) dated to ~1960-1970. The 206Pb/207 Pb ratio of excess Pb (measuring 1.222, and reflecting pollution-generated Pb), when compared with the Pb isotopic composition of the Sandhavn peat record since the 19th century and the timing of Pb enrichments, clearly points to the dominance of pollution sources from North America, although it did not prove possible to further differentiate the emissions sources geographically.
Original language | English |
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Pages (from-to) | 919-930 |
Number of pages | 12 |
Journal | Science of the Total Environment |
Volume | 613-614 |
Early online date | 21 Sept 2017 |
DOIs | |
Publication status | Published - 1 Feb 2018 |
Bibliographical note
We would like to thank Jesús R. Aboal (Universidade de Santiago de Compostela) and Kjell Billström (Naturhistoriska Riksmuseet) for access to the laboratory facilities; Antonio Rodríguez López helped with laboratory work. This research was done under the framework of the projects CGL2010-20672 (Plan Nacional I+D+i, Spanish Ministerio de Economía y Competitividad), R2014/001 and GPC2014-009 (Dirección Xeral I+D, Xunta de Galicia). The authors gratefully acknowledge the financial support of the UK Leverhulme Trust Footprints on the Edge of Thule programme award for core collection and associated environmental research.Keywords
- Hg
- Pb isotopes
- peat
- metal pollution
- isotopic residuals
- atmospheric deposition
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Timothy Mighall
- School of Geosciences, Geography & Environment - Personal Chair
- The North
Person: Academic