SWAYZE_asbestos_spect

Using Imaging Spectroscopy to Measure Asbestos in California, Libby, Montana, and at the World Trade Center in New York : 

Using Imaging Spectroscopy to Measure Asbestos in California, Libby, Montana, and at the World Trade Center in New York Gregg Swayze U.S. Geological Survey Denver, Colorado USGS NASA/JPL USEPA 5th Annual National Asbestos Conference, Baltimore, Maryland, March 2002

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This presentation is divided into three parts that consists of: A progress report on our use of imaging and field spectroscopy to map chrysotile and tremolite asbestos in serpentine rocks in the foothills of the Sierra Nevada in California. N/A Our report on the environmental hazards of the dust released during collapse of the World Trade Center Towers on Sept. 11th.

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High Altitude: 20 km Low Altitude: 2 - 6 km Pixel Size: 2 – 20 m Swath Width: 1 – 11 km Spectral coverage: 0.4 – 2.5 microns 224 spectral channels with 10 nm Bandpass Data collection rate: > 8000 spectra / second AVIRIS NASA / JPL AVIRIS data are first corrected to reflectance and then analyzed with the USGS Tetracorder spectral identification algorithm which creates images color-coded to mineralogy or other materials.

Spectrally Mapping Serpentines in the Sierra Nevada Foothills of California : 

Spectrally Mapping Serpentines in the Sierra Nevada Foothills of California G. Swayze, R. Kokaly, C. Higgins, R. Churchill, D. Ziarkowski, and R. Ashley USGS CalDMG CalEPA

Purpose and Objectives of Study : 

Purpose and Objectives of Study As the population of California grows once rural places like El Dorado County are experiencing high growth. As a result houses are sometimes being built on naturally occurring asbestos deposits. Avoiding this potentially hazardous situation depends on accurate mapping. To test the use of imaging spectroscopy for locating deposits of serpentine rock that can potentially contain chrysotile and amphibole asbestos.

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Study involves sites in Plumas, El Dorado, and Calaveras Counties in the Sierra Nevada Foothills east of Sacramento. Population: El Dorado County (156,000) with a 24% increase from 1990 to 2000. Sacramento San Francisco Study Area

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Characteristic chaparral vegetation cover on serpentine bedrock. Density of vegetative cover may decrease with elevated levels of toxic trace metals in the serpentine.

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Road cut exposing tremolite-bearing gneiss near the town of Latrobe in El Dorado County.

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White fiber bundles of tremolite just above and oriented parallel to the pencil. Weathering of the bundles releases tremolite fibers.

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At a different outcrop chrysotile bundles have been released by weathering.

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Tremolite and chrysotile asbestos can look indistinguishable in hand sample. Spectroscopy can tell the difference in seconds.

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Reflectance spectra of serpentine minerals, tremolite, and chlorite- bearing green schist. Superficially the three serpentine minerals lizardite, chrysotile, and antigorite look alike spectrally but may be distinguished from each other using the 2.1-micron absorption bands. Tremolite has two diagnostic absorptions between 2.3 and 2.4 microns.

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High Altitude AVIRIS Mineral Map AVIRIS and Tetracorder were used to map natural serpentine outcrops in Calaveras County. Serpentine minerals are red and green. Talc/tremolite are yellow. Serpentine minerals were not subdivided, neither were tremolite and talc.

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Low altitude AVIRIS data were collected in late August, 2001 over the major serpentine outcrops in El Dorado County and over Red Mountain in Plumas County. Data were collected at a spatial resolution of 4 x 4 meters per pixel and will hopefully allow us map mineralogy between the plants. We will try to spectrally separate chrysotile from the other serpentine minerals and tremolite from talc with this fine spatial resolution data.

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R. Clark, R. Green, G. Swayze, G. Meeker, S. Sutley, T. Hoefen, E. Livo, G. Plumlee, B. Pavri, C. Sarture, S. Wilson, P. Hageman, P. Lamothe, S. Vance, J. Boardman, I. Brownfield, C. Gent, L. Morath, J. Taggart, P. Theodorakos, and M. Adams USGS NASA/JPL USEPA Environmental Studies of the World Trade Center Dust

Purpose and Objectives of Study : 

Purpose and Objectives of Study Dust released during the collapse of the World Trade Center Towers was reported to contain both chrysotile and amphibole asbestos. Thousands of residents and rescue personnel were exposed to the dust. Evaluating the hazards of the dust would indicate which protective gear would be needed to avoid deleterious health effects among the residents and rescuers. Asbestos content of the dust could be quickly screened over the whole lower Manhattan area using AVIRIS. Dust samples collected around ground zero could be analyzed for mineralogy, pH, and leachable metals using in house labs at the USGS in Denver.

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Bird’s eye view of ground zero. NOAA image collected a few weeks after Sept. 11th.

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AVIRIS arrived in New York on September 15th

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AVIRIS flew on September 16th Twin Otter flights at 12,500 feet and 6,500 feet Spatial resolutions of:4 meters, and2x4 meters.

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AVIRIS saw the fires through the smoke Fire images were delivered to the White House where agencies were briefed on the results and implications. On Tuesday evening Sept. 18th fire fighting methods were changed.

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AVIRIS was able to measure surface temperatures > 800 F in three dozen hotspots. The fires eventually subsided.

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Working Days and Nights at WTC Todd and I spent our days characterizing calibration sites. Nights were spent at the WTC collecting dust and debris samples.

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The type of calibration site we like to used: Stonewall Playa in the Mojave desert in SW Nevada. The calibration site we used: The top level of a parking garage across the Hudson River in Jersey City.

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33 bulk dust samples were collected within a 1 km radius of ground zero. 2 of the dust samples were from indoors. 2 samples of a fireproof coating were collected from steel girders in the debris pile. All samples except one indoor sample were collected Sept. 17 – 19th. Sample location map

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Field Sample Analysis Samples were returned to Denver Sept. 19th and 20th. There they were split and put under “Chain of Custody” rules. Half was archived, the other half was analyzed. Analyses: XRD, SEM, chemistry, leachate pH and metals, XRF, reflectance spectroscopy, visual examination.

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Spectroscopy was done on each sample before any other analysis

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The dust released during the collapse of the WTC towers is largely composed of particles of pulverized fiberglass insulation, gypsum wall board, concrete, paper, plastic, and other miscellaneous materials commonly used in building construction.

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Ground Zero Spectral Shape Map

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Dust leachate pH and conductance values Leachate pH values were slightly alkaline to very alkaline with indoor dust samples having leachate pH’s up to 12.1 using a 20:1 dilution ratio.

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Dust and Girder Coating Leachate Chemistry Relatively high concentrations: Al, Cr, Sb, Mo, Ba, Mn, Cu, and Zn Moderate concentrations: Pb, Se, V Hg elevated in indoor dust samples (up to 130 nanograms/L). Parts per billion Al Cr Sb Mo Ba Mn Cu Zn Pb Se V Hg

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50 mm Chrysotile Mineral glass fiber SEM micrograph of fireproof coating collected from a steel girder from the debris pile. Sample WTC01-8 contains up to 20 wt% chrysotile.

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AVIRIS asbestos map This mineral map looks nearly devoid of color because AVIRIS detected only small localized pockets of possible highly- concentrated asbestos. Within a week of data collection we were able to determine that there was no wide spread highly concentrated asbestos in the dust above 5 wt% for all of lower Manhattan.

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Chrysotile content in the WTC surface samples This map is based on both spectroscopic and X-ray diffraction analysis of the bulk samples. Lower detection threshold: XRD: 1wt% Spectroscopy: 0.25–1wt% depending on level of spectral interference. No bulk samples contained greater than 1 wt% chrysotile. These methods were not used to evaluate the airborne fraction of chrysotile.

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Conclusions AVIRIS data collected on Sept. 16th revealed more than three dozen hotspots in the debris pile at ground zero. Thermal images supplied to emergency workers may have helped fire fighters focus their efforts within three days of the AVIRIS flight. AVIRIS was successfully used to screen the WTC dust for asbestos content with results made available to emergency workers within two weeks of the disaster. Apart from a few isolated pockets no wide spread highly concentrated asbestos was found above 5 wt% sensitivity threshold of AVIRIS.

More Conclusions : 

More Conclusions Chrysotile was found in over two thirds of the bulk dust samples but at concentrations no greater than 1 wt%. One sample of a girder coating contained up to 20 wt% chrysotile asbestos. Dust leachate solutions of indoor samples can be very alkaline with pH’s up 12. Metals and metalloids can be readily leached from the dusts into rain or wash water with indoor dust samples having the highest concentrations. These metals may also be potentially bioavailable if the dusts are accidentally inhaled or ingested.

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Our full report, about 250 printed pages as well as full resolution AVIRIS and SEM images is available at: http://speclab.cr.usgs.gov