1. WORKING FOR A HEALTHY FUTURE
Calibration of the DREAM model for
the dermal exposure assessment of
workers in theGuLFSTUDY
John W Cherrie1, Melanie Gorman Ng1, Anne Sleeuwenhoek1,
Mark Stenzel2, Richard Kwok3, Berna van Wendel de Joode4,
Patricia Stewart5
1 Institute of Occupational Medicine, Centre for Human Exposure Science (CHES)
2 Exposure Assessment Applications, LLC
3 National Institute of Environmental Health Sciences
4 Universidad Nacional de Costa Rica
5 Stewart Exposure Assessments, LLC
INSTITUTE OF OCCUPATIONAL MEDICINE . Edinburgh . UK www.iom-world.org
2. WORKING FOR A HEALTHY FUTURE
Calibration of the DREAM model for
the dermal exposure assessment of
workers in theGuLFSTUDY
John W Cherrie1, Melanie Gorman Ng1, Anne Sleeuwenhoek1,
Mark Stenzel2, Richard Kwok3, Berna van Wendel de Joode4,
Patricia Stewart5
1 Institute of Occupational Medicine, Centre for Human Exposure Science (CHES)
2 Exposure Assessment Applications, LLC
3 National Institute of Environmental Health Sciences
4 Universidad Nacional de Costa Rica
5 Stewart Exposure Assessments, LLC
INSTITUTE OF OCCUPATIONAL MEDICINE . Edinburgh . UK www.iom-world.org
3. Summary…
• Original studies to validate DREAM
• GuLF DREAM
• Two examples using the adapted model
• Preliminary data to help validate the
adapted model
2
4. Original DREAM studies…
• Fully described in initial paper, implemented in
Microsoft Access
• The accuracy was assessed by comparing
DREAM assessments with measured exposure
• Hands and other body parts
• Variety of measurement methods, removal and
interception samplers
• Six different situations/agents
• Spearman correlation coefficients for individual
observations ranged from 0.19 to 0.82
van Wendel de Joode B, Vermeulen R, van Hemmen JJ, et al. Accuracy of a
semiquantitative method for Dermal Exposure Assessment (DREAM). Occup 3
Environ Med 2005;62:623–32.
5. GuLF DREAM
Body surface
factor
Emission Deposition
Transfer
Clothing
4
7. Boom deployment, near shore…
• Deployed by small vessels
• Oil was present on the water
• Occasionally had to anchor
the boom
• could result in the oil or oily
water contacting hands.
• Hands, forearms, and
trouser legs probably got
wet with water at times
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8. Boom retrieval, near shore…
• Retrieved by vessels or boats of all sizes, but on
small boats mainly manual work
• Significant opportunity for contact of hands, arms,
legs and torso with oil and oily water
• Wore safety glasses, abrasion-
resistant work gloves (e.g.
(leather), rubber boots, and
a high-visibility garment
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9. Validation and calibration
• Validate and calibrate revised model against measurement
data
• Have identified sources of dermal exposure measurement
data with contextual information that can be used to make
DREAM assessments
• IOM (heavy fuel oil) Oil and tar
• Herrick et al (asphalt)
• Soutar et al (biocides)
• Hines et al (pesticides) Dispersants
• Stewart et al (pesticides)
• Van Wendel de Joode et al (Original DREAM data)
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12. Discussion…
• There are no dermal exposure data for the GuLF
study!
• Updated model provides a promising basis for
exposure reconstruction
• Some weaknesses in current model…
• Evaporation and wind speed
• Contaminated clothing
• Water and washing
• Sticky liquids!
• Validation problematic because of limited data
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Notas del editor
Thanks, acknowledge co-authors and sponsorship
Thanks, acknowledge co-authors and sponsorship
For skin exposures to the hands, spearman correlation coefficients for individual observations ranged from 0.19 to 0.82. CP removal, OS surrogate skin, MWF flourescence
Estimating alkylatedPAHsLarge part of the difference due to PF for gloves and clothing, e.g. for gloves the net PF went from 0.03 to 0.35