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Geologic sources of asbestos in Seattle's tolt reservoir

January 1, 1996

Water from Seattle's South Fork Tolt Reservoir contains chrysotile and amphibole asbestos fibers, derived from natural sources. Using optical petrographic techniques, X-ray diffraction, and scanning electron microscopy, we identified the geologic source of these asbestiform minerals within the watershed. No asbestos was found in the bedrock underlying the watershed, while both chrysotile and amphibole fibers were found in sediments transported by Puget-lobe glacial processes. These materials, widely distributed throughout the lower watershed, would be difficult to separate from the reservoir sediments. The probable source of this asbestos is in pods of ultramafic rock occurring north of the watershed. Because asbestos is contained in widespread Pugetlobe glacial materials, it may be naturally distributed in other watersheds in the Puget Sound area.

Publication Year 1996
Title Geologic sources of asbestos in Seattle's tolt reservoir
Authors M.E. Reid, G. Craven
Publication Type Article
Publication Subtype Journal Article
Series Title Northwest Science
Index ID 70019368
Record Source USGS Publications Warehouse