A novel biomonitoring method to detect pyrethroid metabolites in saliva of occupationally exposed workers as a tool for risk assessment

Abstract

Saliva is valuable in exposure assessment having been successfully used for drug and environmental pollutant detection, providing a surrogate measure of plasma concentrations. Pyrethroid biomarkers have not previously been assessed in saliva, although are prime candidates for saliva detection. This study’s objectives were to (1) develop a liquid-liquid extraction (LLE) method to quantify six pyrethroid metabolites using gas chromatography/ion trap mass spectrometry and (2) assess its application for an occupationally exposed population. Several solvents and mixing protocols were optimized for metabolite recovery. The optimized method was applied to a population of pest control operators (PCOs) and compared against a urine sample before and after a full workday using pesticides. A questionnaire collected demographic information, occupational history, and occupational and non-occupational exposure data. LLE recoveries ranged from 85–104% and 72–88% for toluene and dichloromethane using slow mixing, and 49–103% for methyl tert-butyl ether by fast mixing. Urinary 3-Phenoxybenzoic acid (3PBA) was detected in 100% of pre- and post-work urine samples. Three PCOs had increased urinary pyrethroid metabolite levels post-work. Salivary 3PBA was present below detection limit in two of the three PCO’s post-work saliva samples, demonstrating that salivary 3PBA could be measured in PCOs after the workday. This study presents preliminary findings of a potential, low-risk biomonitoring technique that may be utilized in future occupational pyrethroid exposure and risk assessment research.

Keywords:

• Saliva
• pyrethroids
• metabolites
• GCITMS
• exposure assessment

SUSTAINABLE DEVELOPMENT GOALS:

• S DG 9: Industry, innovation and infrastructure

Acknowledgments

Acknowledgements to Tri-County Termite and Pest Control Inc. and the employees that participated in this study. Thank you to Patrick Kenny MPH, who liaised with Tri-County Termite and Pest Control Inc. and assisted with recruitment and field work. The authors acknowledge the Rutgers – New Jersey Agricultural Experiment Station for their participation and support. This study was supported by the National Institute of Environmental Health Sciences (P30ES005022) and National Instituteof Environmental Health Sciences (T32ES019854 and T32ES007148).

Author contributions

Melody Wren was responsible for sample collection and analysis, data analysis, result interpretation, and manuscript writing. Brian Buckley was responsible for funding acquisition, results interpretation, manuscript editing, and content review. Mark Robson was responsible for recruitment, results interpretation, and content review.

Disclosure statement

No potential competing interest is reported by the author(s).

Additional information

Funding

This work was supported by the NIEHS under Grant [P30ES05022] and NIEHS under Grants [T32ES019854 and T32ES007148].