Isotopic evidence for the source of lead in the North Pacific abyssal water

Jingfeng Wu, Robert Rember, Meibin Jin, Edward A. Boyle, A. Russell Flegal

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Abstract

The absence of accurate measurements of lead (Pb) isotopic composition in the North Pacific abyssal water has made it difficult to assess the relative importance of what are believed to be the two major Pb sources: the natural Pb introduced during preindustrial time and recent anthropogenic Pb resulting from leaded gasoline combustion and high temperature industrial activities. Here we report a vertical profile of seawater 206Pb/207Pb ratio and a meridional section of Pb concentration in the North Pacific Ocean. We observe 2-3-fold increases in Pb concentration along the deep-water flow path and a deep-water 206Pb/207Pb ratio (∼1.188) substantially lower than the pre-industrial value (∼1.210). These data suggest that anthropogenic Pb has invaded the North Pacific abyssal water and become the predominant Pb source there. A simple model calculation based on these data indicates that the anthropogenic Pb is transported to the deep ocean by sinking particles and that this Pb vertical flux has a 206Pb/207Pb ratio that decreased during the past two centuries.

Original languageEnglish (US)
Pages (from-to)4629-4638
Number of pages10
JournalGeochimica et Cosmochimica Acta
Volume74
Issue number16
DOIs
StatePublished - Aug 1 2010

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ASJC Scopus subject areas

  • Geochemistry and Petrology

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