Solvents
Thousands of toxicants are continuously emitted into the environment
and, as a consequence, the general population is exposed to a large
number of pollutants inhaled via air, ingested with food, and adsorbed
through skin. The pollutants benzene, toluene, ethylbenzene, xylenes
(BTEX), methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE),
and naphthalene represent an important group of airborne contaminants.
BTEX (monocyclic aromatic chemicals), and MTBE and ETBE (oxygenated
compounds belonging to the class of ethers) are mainly used as additives
in gasoline to enhance octane rating, in replacement of alkyl-lead
compounds, and to improve the combustion process. The presence of the
aforementioned chemicals in outdoor air has been largely associated with
fuels, as components of both vehicular exhaust fumes and vapors.
Moreover, toluene, ethylbenzene and xylene are components of several
household products for cleaning, personal care, and painting, and
therefore represent additional indoor air contaminants. BTEX and
naphthalene are also present in main- and side-stream tobacco smoke,
which provides one of the largest sources of personal exposure to air
pollutants.
The interest of our group in the biomonitoring of the exposure to
solvents is documented in several publications starting from 1995. Below
the study chemicals are reported in details.
BENZENE
Benzene is a known carcinogen to humans, and evidence indicates that
benzene causes hematotoxicity at exposure levels below 1 ppm. Research
on benzene was devoted to develop specific and sensitive methods to
quantify both urinary benzene [Fustinoni et al., 1999; Perbellini et
al., 1999] and urinary metabolites of benzene [Buratti et al., 1996;
Buratti et al., 2001], comparing their intrinsic characteristics and
suitability to assess exposure at occupational and environmental levels
[Fustinoni, 2010d; Fustinoni et al., 2011; Lovreglio et al., 2011]. The
exposure to benzene was evaluated in traffic wardens [Fustinoni et
al.,1995; Campo et al., 2011], in petrol station attendants [Fustinoni
et al., 2005c; Farmer et al., 2005; Fustinoni et al., 2005d], in
petrochemical workers [Fustinoni et al., 2012a], in solvent workers
[Waidianatha et al., 2001], in office workers [Carrer et al., 2000], and
in the general population [Fustinoni et al., 2012a; Campagna et al.,
2012; Campagna et al., 2014; Ranzi et al., 2013]. The epigenetic changes
related to benzene exposure were also studied [Bollati et al., 2007;
Hoxha et al., 2009; Carugno et al., 2012; Zhu et al., 2012; Fustinoni et
al., 2012b].
TOLUENE,
ETHYLBENZENE, AND XILENE
Toluene, ethylbenzene, and xilenes are very common chemicals, widely
used as solvents in paints, coatings and many consumer products, as
synthetic intermediates and as additives in fuel. From a toxicological
point of view, these chemicals are neurotoxic. Specific methods for the
quantification of both urinary or blood compounds [Fustinoni et al.,
1999] and their urinary metabolites [Buratti et al., 2001; Fustinoni et
al., 2005b] were developed and the different biomarkers were evaluated
for their characteristics [Fustinoni et al., 2000; Fustinoni et al.,
2007; Fustinoni et al., 2009]. Environmental and biological monitoring
of exposure to these compounds was assessed in workers such as
rotogravure printing workers [Fustinoni et al., 2005b], office workers
[Carrer et al., 2000; Fustinoni et al., 2005d; Campo et al., 2011b], and
in the general population [Fustinoni et al., 2010b; Fustinoni et al.,
2005d; Ranzi et al., 2013].
MTBE and ETBE
Oxygenated hydrocarbons, such as ethers (MTBE and ETBE) and alcohols,
are blended into petrol in any proportion up to 15% by volume as
additives to improve the fuel combustion and enhance octane rating. MTBE
is classified as not carcinogenic to humans. A specific method to
quantify ethers in urine has been developed [Scibetta et al., 2007] and
MTBE has been evaluated as a biomarker of exposure to urban traffic in
traffic wardens [Campo et al., 2011] and in the general population
[Fustinoni et al., 2010b].
STYRENE
Styrene is an important industrial chemical that is used primarily in
the production of plastics, resin, and synthetic rubber. Occupational
exposures to styrene are accompanied by co-exposures to low levels of
styrene-(7,8)-oxide (StyOX), which is produced from oxidation of styrene
during the production of plastics. Styrene and StyOX are classified as
possible and probable human carcinogens, respectively. Research of our
group on styrene has been devoted to elucidate the relationships between
blood-protein adducts and other styrene biomarkers [Fustinoni et al.
1998], and to compare several potential biomarkers of exposure to
styrene and StyOX taking in account the influence of cigarette smoking
and genetic polymorphisms as potential confounders and using a repeated
measurement sampling design [Fustinoni et al., 2008a] to assess the
variability of the studied biomarkers [Fustinoni et al., 2010a].
1,3-BUTADIENE
(BD)
BD is a chemical widely used for rubber, resin, and latex
production. Besides exposures in occupational settings, BD is a
ubiquitous pollutant; major sources of exposure in the general
population are cigarette smoke and automobile exhausts. BD is classified
as a probable carcinogen to humans. The research on BD was focused on
evaluating the influence of genetic polymorphisms of enzymes involved in
BD metabolism on the excretion of urinary metabolites and the levels of
hemoglobin adducts in workers exposed to low levels of BD and in
unexposed subjects [Begemann et al., 2001; Fustinoni et al., 2002;
Fustinoni et al., 2004], and on evaluating the genotoxic effect of BD
exposure [Lovreglio et al., 2006; Buckvic et al., 2009], the glutathione
transferase activities, and the levels of glutathionylated hemoglobin
[Primavera et al., 2008].