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Vertical concentration profiles of lead in the Central Pacific at 15°N and 20°S

Flegal, A. R. and Patterson, C. C. (1983) Vertical concentration profiles of lead in the Central Pacific at 15°N and 20°S. Earth and Planetary Science Letters, 64 (1). pp. 19-32. ISSN 0012-821X. https://resolver.caltech.edu/CaltechAUTHORS:20140819-125201198

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Abstract

Concentrations of lead were measured in a surface transect and at two vertical profile stations (15°N and 20°S) in the Central Pacific. These measurements complement similar measurements made earlier in the North Pacific at 33°N and in the Northwest Atlantic at 34°N, as well as recent measurements of eolian lead input fluxes near each of these locations. The new transect of surface water concentrations of lead corroborates previous measurements, which decrease from 13 ng/kg at 30°N to 4 ng/kg at 17°S in the Central Pacific. This transect gradient is shown to overlie a similar geographic gradient of subsurface maximum concentrations of lead in the three Pacific vertical profile stations, decreasing from 14 ng/kg at 33°N to 11 ng/kg at 14°N to 2.5 ng/kg at 20°S. Lead concentrations at each of those locations exhibit maxima at 400 m, decreasing concentrations to 2500 m and approximately concentrations of 0.8–1.1 ng/kg below that depth. The subsurface maximum at the northwest Atlantic profile station (36 ng/kg at 34°N) is also congruent with surface water lead concentrations which decrease from 806 ng/kg to 32 ng/kg in an offshore transect from Rhode Island to 34°N, 66°W, and the shape of the Atlantic profile is congruent with those in the Pacific. There is a positive correlation between the magnitudes of eolian lead input fluxes and the magnitudes of the upper water maxima in lead concentration profiles at corresponding locations as follows: South Pacific easterlies 3 ng/cm^2 yr vs. 2.5 ng/kg; North Pacific easterlies 6 ng/cm^2 yr vs. 11 ng/kg; North Pacific westerlies 50 ng/cm^2 yr vs. 14 ng/kg; and North Atlantic westerlies 170 ng/cm^2 yr vs. 36 ng/kg. This relationship enables one to view the anthropogenic perturbations of the marine lead cycle on a global scale, since the industrial origin of eolian and seawater lead has been established by correlations between geographic patterns of industrial lead emissions to the atmosphere and isotopic ratios of industrial leads and by geographic patterns of Pb/silicate-dust ratios and lead isotopic ratios in ocean surface waters. These new data coupled with earlier biogeochemical data indicate that surface water concentrations of lead in the North Pacific and North Atlantic are now conservatively estimated to be 8 to 20-fold greater and those in the South Pacific are 2-fold greater than natural concentrations because of industrial emissions of lead to the atmosphere.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/0012-821X(83)90049-3DOIArticle
http://www.sciencedirect.com/science/article/pii/0012821X83900493PublisherArticle
Additional Information:© 1983 Elsevier Science Publishers B.V. Received July 6, 1982. Revised version received March 24. 1983. Available online 23 October 2002. This research has been supported by NSF grants OCE 7900696 and OCE 8113211, Marine Chemistry Division of Ocean Sciences. We are grateful to B. Schaule who cleaned, assembled, and packaged the CIT sampler, G. Gill and S. Nakamura who collected the samples, K. Bruland, principal investigator on the FGGE cruise, who supervised the sample collection, D. Settle who contributed analytical expertise, and M. Murozumi who intercalibrated the seawater analyses with us. We thank D. Settle and B. Schaule for their permission to quote unpublished data from the Flegal et al. [4] manuscript, and A. Ng, K. Bruland and B. Schaule for their permission to quote unpublished data from the Ng et al. [5] manuscript.
Funders:
Funding AgencyGrant Number
NSFOCE 7900696
NSFOCE 8113211
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences3794
Issue or Number:1
Record Number:CaltechAUTHORS:20140819-125201198
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140819-125201198
Official Citation:A.R. Flegal, C.C. Patterson, Vertical concentration profiles of lead in the Central Pacific at 15°N and 20°S, Earth and Planetary Science Letters, Volume 64, Issue 1, July 1983, Pages 19-32, ISSN 0012-821X, http://dx.doi.org/10.1016/0012-821X(83)90049-3. (http://www.sciencedirect.com/science/article/pii/0012821X83900493)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48686
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:19 Aug 2014 20:27
Last Modified:03 Oct 2019 07:06

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