A Dirichlet Tessellation-based sampling scheme for measuring whole-body exposure.

Area of Science:

• Occupational Health and Safety
• Environmental Science
• Analytical Chemistry

Background:

• Dermal exposure assessment is crucial for chemical risk evaluation.
• Current methods like patch sampling have limitations in accuracy due to non-uniform deposition.
• Whole-body coverall sampling offers potential for more accurate exposure estimation.

Purpose of the Study:

• To develop and validate a standardized protocol for measuring whole-body dermal contamination.
• To compare the accuracy of a novel Dirichlet tessellation-based PXRF method against traditional patch sampling and whole-suit digestion.
• To improve the spatial resolution and accuracy of dermal exposure assessments.

Main Methods:

• Development of a standardized sampling protocol for whole-body coveralls, accounting for size variations.
• Application of portable X-ray fluorescence spectrometry (PXRF) to measure copper contamination on sampled areas.
• Utilizing Dirichlet tessellation for averaging PXRF measurements to estimate total body exposure, benchmarked against whole-suit acid digestion.

Main Results:

• The Dirichlet tessellation-based PXRF method achieved a mean absolute percentage error of approximately 20% compared to the benchmark.
• Patch sampling methods underestimated dermal exposure significantly ( -28% to -82%) with errors up to 60%.
• The new method provided higher spatial resolution data compared to ICP-AES analysis of whole suits or patches.

Conclusions:

• The Dirichlet PXRF method offers a more accurate and spatially resolved assessment of whole-body dermal contamination than patch sampling.
• This improved methodology can lead to better chemical risk assessments by providing detailed deposition patterns.
• The developed protocol enables accurate and rapid measurement of contamination on entire coveralls.