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Open-File Report 2006-1362

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Prepared for U.S. Environmental Protection Agency Region 9 IAG DW1492190501-2

Mineralogy and Morphology of Amphiboles Observed in Soils and Rocks in El Dorado Hills, California

By G.P. Meeker, H.A. Lowers, G.A. Swayze, B.S. Van Gosen, S.J. Sutley, and I.K. Brownfield

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From the Executive Summary

At the request of the U.S. Environmental Protection Agency (USEPA), the U.S. Geological Survey (USGS) has conducted an independent study of amphiboles in rocks and soils in the El Dorado Hills, California, area. The purpose of this study is to investigate specific issues regarding the presence of “naturally occurring asbestos” raised by an USEPA activity-based sampling study and subsequent criticisms of that study outlined in a review prepared by The R.J. Lee Group (RJLG).

Version 1.0

Posted December 2006

An aerial photo map of the El Dorado Hills study area showing USGS sampling locations (Figure A1) and a spreadsheet with sampling site descriptions (Table A1).
Optical photomicrographs of polished thin sections and electron photomicrographs showing the locations of EPMA analysis points.
Electron photomicrographs of particles from USGS soil and stub samples analyzed on the SEM.
A spreadsheet that includes tables of EPMA data, SEM data, and size data for particles analyzed in sample ED06-07A.

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