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Lead in the western South China Sea: Evidence of atmospheric deposition and upwelling
Author(s) -
Chen Mengli,
Goodkin Nathalie F.,
Boyle Edward A.,
Switzer Adam D.,
Bolton Annette
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl068697
Subject(s) - upwelling , coral , oceanography , environmental science , porites , lead (geology) , δ15n , geology , δ13c , stable isotope ratio , geomorphology , physics , quantum mechanics
In recent decades, rapid industrial developments have increased lead (Pb) inputs to the South China Sea. To quantify the increasing variability, we investigated 170 years of skeletal Pb and Pb isotopes from an offshore, central Vietnamese coral. The Pb/Ca in the coral was 10–16 nmol/mol before the mid‐1950s and increased to more than 30 nmol/mol by 2000. While the regional phaseout of leaded petrol commenced in 2000, coral Pb/Ca continued increasing until 2004, possibly due to regional upwelling and the transport of previously emitted Pb from tropical Pacific waters. The 206 Pb/ 207 Pb ratio in the coral was 1.191–1.195 before mid‐1950s, suggesting natural sources. Since then, the ratio decreased, reaching ~1.165 in 2004. Lead isotopes show high linearity between natural and Chinese emitted Pb, with the latter contributing ~40%~60% of the skeletal Pb after 2000.