Modeling Real-Time Occupational Naphthalene Exposures to Predict Urinary Biomarkers
Abstract
A novel real-time naphthalene dosimeter (NaDos) prototype, sponsored by the U.S. Army, provides the capability for close monitoring of naphthalene concentration measurements to identify changes in occupational exposures. Quantitative real-time monitoring has the potential to be more accurate than traditional dosimeters that rely on sorbent tubes to provide a time weighted average of exposure concentrations following laboratory analysis. Continuous data (every 3 minutes) were collected from military fuel workers wearing the NaDos prototype monitors. Data included biometric information (height, weight and sex), traditional work day naphthalene breathing zone measurements, and spot urine samples during 3 consecutive work days. Urine was analyzed for 1- and 2-naphthol and creatinine content. Additionally, hand wash wipe and exhaled breath samples were collected post-shift; however, there were few results above the naphthalene limit of detection. In order to simulate real-time exposure data, a novel physiologically-based pharmacokinetic (PBPK) model was written to simulate the changing concentrations inhaled over time. The model structure accounted for naphthalene metabolism in the lung and liver, as well as production, distribution and urinary elimination of metabolites (combined naphthols). To predict urinary concentration, the model estimated urinary flow and creatinine production based upon sex, age and body mass index. Given data limitations, the naphthalene model satisfactorily simulated urine naphthol concentrations or creatinine normalized naphthol concentrations for most individual datasets.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 2019
- Accession Number
- AD1090903
Entities
People
- Elaine A. Merrill
- Janis E. Hulla
- Peter J. Robinson
- Susan P. Proctor
- Teresa R Sterner
Organizations
- Henry M. Jackson Foundation for the Advancement of Military Medicine