Lead in the western South China Sea: Evidence of atmospheric deposition and upwelling

TitleLead in the western South China Sea: Evidence of atmospheric deposition and upwelling
Publication TypeJournal Article
Year of Publication2016
AuthorsChen M, Goodkin NF, Boyle EA, Switzer AD, Bolton A
JournalGeophysical Research Letters
Volume43
Issue9
Pagination4490-4499
Date Published05/2016
Abstract

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 Pb-206/Pb-207 ratio in the coral was 1.191-1.195 before mid-1950s, suggesting natural sources. Since then, the ratio decreased, reaching similar to 1.165 in 2004. Lead isotopes show high linearity between natural and Chinese emitted Pb, with the latter contributing similar to 40%similar to 60% of the skeletal Pb after 2000.

DOI10.1002/2016GL068697