Application of a Non-targeted Biomonitoring Method to Characterize Occupational Chemical Exposures of Women Nurses Relative to Office Workers

We analyzed blood serum samples from two unique female
occupational
cohorts – 60 nurses and 40 office workers in San Francisco,
CA – using liquid chromatography and high-resolution mass spectrometry
(quadrupole time-of-flight). Applying a nontargeted analysis (NTA)
approach, we sought to isolate occupationally related chemical exposures
that were unique to nurses by flagging features that were different
from office workers in abundance (mean; 95th percentile) or detection
frequency. Of 9828 negative electrospray ionization (ESI-) and 6898
positive electrospray ionization (ESI+) detected chemical features,
1094 and 938, respectively, were higher in nurses, possibly due to
workplace exposures. We deciphered the molecular structures of these
chemical features by applying data-dependent acquisition (DDA) and
targeted MS/MS approaches to pooled samples from each occupational
group, and we annotated them using spectral MS/MS databases in MS-DIAL.
Nurses had higher concentrations of 14 chemicals that we identified
at Schymanski Level 1 (N = 6) or 2 (N = 8), as well as 20 tentatively
identified chemicals without spectra. Several chemicals may be occupationally
relevant for nurses, including a PFAS (6:2 fluorotelomer sulfonic
acid), tridecanedioic acid, salicylic acid, and the medications acetaminophen
and theophylline. To our knowledge, this study is the first to apply
NTA to elucidate novel chemical exposures in nurses.