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Published February 1980 | public
Journal Article

Chronological variations in concentrations and isotopic compositions of anthropogenic atmospheric lead in sediments of a remote subalpine pond

Abstract

Lead concentrations decrease 4-fold in going from the surface of sediments in a mountain pond to relatively small values in layers 130 yr old. There is a corresponding change in the Pb^(206)/Pb^(207) ratio in the sediments from industrial-like values of 1.18 near the surface to natural values of 1.24 at depth. Concentrations of Ca, Sr, and Ba remain relatively constant with depth. The excess Pb is shown to be of eolian anthropogenic origin, through isotopic, chemical, and mass balance relationships with metals in aerosols, dry deposition, and precipitation. This proves that inputs of contamination Pb were nearly absent centuries ago in a remote non-domesticated subalpine canyon, but are present today in that ecosystem in amounts more than 20 times the natural inputs and are irrefutably linked with industrial sources. As a consequence of these inputs, present Pb concentrations have been elevated 5-fold in plants and 50-fold in animals above natural levels. These Pb contamination effects are being caused by present-day atmospheric concentrations of ~10 ng Pb/m^3. The ecosystem studied here characterizes the vast remote non-domesticated regions of North America, and these findings indicate that such regions are highly polluted by industrial Pb aerosols.

Additional Information

© 1980 Pergamon Press Ltd. Received 23 January 1979; accepted in revised form 19 September 1979. Contribution No. 3186: Division of Geological and Planetary Sciences. California Institute of Technology. A. SOUTAK. University of California, San Diego, cut and X-rayed the frozen cores. K. K. BERTINE, California State University and E. D. GOLDBERG, University of California, San Diego, provided a design for the coring device. GOLDBERG and his colleagues, and SOUTAR and his colleagues pioneered the Pb^(210) dating techniques of sediment cores, as well as techniques for collecting and dissecting these cores. Our work was made possible by these pioneering developments. A. NC, D. SETTLE. and R. AINE. California Institute of Technology, assisted in sampling and chemical procedures. We are pleased to acknowledge this assistance and the helpful advice these people provided in discussions of the work, which was supported by NSF grant DEB73-01306 A01, We also thank Dr J. W. VAN WAGTENDONKR, Research Scientist, National Park Service, for arranging that this work could be carried out in Yosemite National Park.

Additional details

Created:
August 19, 2023
Modified:
October 26, 2023