01/09/2014

Systemic Exposure to PAHs and Benzene in Firefighters Suppressing Controlled Structure Fires

Turnout gear provides protection against dermal exposure to contaminants during
firefighting; however, the level of protection is unknown. scientists explored
the dermal contribution to the systemic dose of polycyclic aromatic
hydrocarbons (PAHs) and other aromatic hydrocarbons in firefighters during
suppression and overhaul of controlled structure burns.

The study was organized into two rounds, three controlled burns per round, and
five firefighters per burn. The firefighters wore new or laundered turnout gear
tested before each burn to ensure lack of PAH contamination. To ensure that any
increase in systemic PAH levels after the burn was the result of dermal rather
than inhalation exposure, the firefighters did not remove their self-contained
breathing apparatus until overhaul was completed and they were >30 m upwind
from the burn structure. Specimens were collected before and at intervals after
the burn for biomarker analysis. Urine was analyzed for phenanthrene
equivalents using enzyme-linked immunosorbent assay and a benzene metabolite
(s-phenylmercapturic acid) using liquid chromatography/tandem mass
spectrometry; both were adjusted by creatinine. Exhaled breath collected on
thermal desorption tubes was analyzed for PAHs and other aromatic hydrocarbons
using gas chromatography/mass spectrometry. We collected personal air samples
during the burn and skin wipe samples (corn oil medium) on several body sites before and after the burn.


The air and wipe samples were analyzed for PAHs using a liquid chromatography
with photodiode array detection. We explored possible changes in external
exposures or biomarkers over time and the relationships between these variables
using non-parametric sign tests and Spearman tests, respectively. The
scientists found significantly elevated (P < 0.05) post-exposure breath
concentrations of benzene compared with pre-exposure concentrations for both
rounds. We also found significantly elevated post-exposure levels of PAHs on
the neck compared with pre-exposure levels for round 1.


They found statistically significant positive correlations between external
exposures (i.e. personal air concentrations of PAHs) and biomarkers (i.e.
change in urinary PAH metabolite levels in round 1 and change in breath
concentrations of benzene in round 2).


The results suggest that firefighters wearing full protective ensembles
absorbed combustion products into their bodies. The PAHs most likely entered
firefighters' bodies through their skin, with the neck being the primary site
of exposure and absorption due to the lower level of dermal protection afforded
by hoods. Aromatic hydrocarbons could have been absorbed dermally during
firefighting or inhaled during the doffing of gear that was off-gassing
contaminants.

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AplusA-online.de - Source: The Annals of Occupational Hygiene