Measurement of Benzo[A]Pyrene as a Surrogate for Total Human Exposure to PAH

ABSTRACT

This is a brief overview of our use of benzo[a]pyrene (B[a]P) as a surrogate of human exposure starting with exploration of this “multi-media” pollutant in the THEES study and continuing with explorations of the monitoring of this substance as a metabolite in human urine. In the THEES pilot study the predominant pathway of exposure was usually the ingestion pathway. The analysis of urinary metabolites using the Becher/Bjørseth “reverse metabolism” technique provided very low yields (ca 5 % recovery) for B[a]P metabolites although it works well for lower molecular weight metabolites. Current interest focuses on the recovery of conjugates (Phase 2 metabolites) since deconjugation in workup involves loss of information. A study of rat urine and feces indicated that the metabolite mixture varied with installation pathway- i.e. gastric versus intratracheal installation of B[a]P. We are exploring new methods for the isolation and separation of individual conjugates such as the hydroxy-PAH sulfates.

Key words::

• Benzo[a]pyrene
• Total Human Exposure
• Sulfate Conjugates
• Urinary PAH