Polycyclic Aromatic Hydrocarbons
Polycyclic
aromatic hydrocarbons (PAHs) are a class of organic compounds made of
two or more condensed aromatic rings. Since PAHs are produced during
incomplete combustion of organic matter, they are widespread in the
environment as pollutants and are always present as a complex mixture.
Some industrial activities, such as coke production, coal gasification,
coal tar distillation, aluminum production, or coal tar pitch
paving/roofing, are associated with high levels of occupational PAH
exposure. The general population may be exposed to PAHs via inhalation
of polluted air or cigarette smoke, ingestion of
charbroiled/fried/smoked/ toasted food, or dermal contact with
contaminated soil and dust.
PAHs are
recognized as persistent organic pollutants, and 17 compounds in
particular have been classified as priority pollutants by the United
States Environmental Protection Agency (U.S. EPA). Some PAHs have been
classified as carcinogenic or probably/possibly carcinogenic to humans
by several international agencies and governmental bodies such as the
International Agency for Research on Cancer (IARC), and the European
Commission. Moreover, exposure to PAHs has also been associated with
adverse reproductive, neurodevelopmental and cardiovascular outcomes.
The measurement
of PAH exposure is essential due to the potential associated health
risks. Biological monitoring, integrating all possible routes of
exposure and reflecting personal characteristics of monitored subjects,
is a useful tool to assess internal PAH levels. Currently, the
measurement of 1-hydroxypyrene, a metabolite of non-carcinogenic pyrene,
is used as a biomarker for PAH exposure. However, in recent years, the
simultaneous measurement of multiple hydroxylated urinary metabolites of
PAHs and unmetabolized parent compounds in urine or blood have been
proposed as alternative approaches for measuring PAH exposure. This
multi-compound analysis approach is very promising since it enables
better characterization of exposure to both complex PAH mixtures as well
as single compounds of interest.
The research of
our group is dedicated to support this multi-compound analysis approach,
by both developing sensitive assay and assessing multiple-PAHs exposure
in workers and in the general population.
Several
analytical methods were developed in this frame: 1) A gas
chromatography–isotope dilution mass spectrometry (GC-IDMS) method to
quantify 12 urinary monohydroxy metabolites of PAHs [Campo et al.,
2008]; 2) a headspace solid-phase microextraction gas
chromatography–isotope dilution mass spectrometry method
(HS-SPME/GC-IDMS) for the quantification in urine samples of 13 two- to
four-ring PAHs [Campo et al., 2009], 3) a HS-SPME/GC-MS for the
quantification in urine samples of monohydroxy metabolites of PAHs after
in-situ derivatization [Mattarozzi et al., 2009], 4) a SPME/GC-IDMS with
improved sensitivity and specificity to quantify five- and six-ring PAHs
[Campo et al., 2011a].
The developed
methods were applied to assess levels and routes of exposure in several
occupational and environmental settings. In Italian road construction
workers exposed to asphalt emission the exposure to 16 PAHs was assessed
by measuring personal airborne exposure [Campo et al, 2006b; Cirla et
al., 2007; Buratti et al., 2007a], dermal absorption [Fustinoni et al.,
2010c], and the total body uptake [Campo, 2006a; Campo et al., 2006b;
Campo et al, 2007; Buratti et al., 2007b; Campo et al., 2011c]. Exposure
to PAHs was also assessed in coke oven workers comparing different
urinary biomarkers [Rossella et al., 2009a; Campo et al., 2010] and
investigating the occupational determinants of exposure [Campo et al.,
2014, IJHEH], also in relation to the actual occupational and
environmental limit values [Campo et al., 2012]. The possible exposure
to PAHs was investigated in the general population living near coke-oven
plants [Campo et al., 2014; Campo et al., 2012] or solid-waste
incineration plants [Ranzi et al., 2013].
