DNA adducts and strand breaks in workers exposed to vapours and aerosols of bitumen: associations between exposure and effect

Abstract

To study the associations between exposure to vapours and aerosols of bitumen and genotoxic effects, a cross-sectional and cross-shift study was conducted in 320 exposed workers and 118 non-exposed construction workers. Ambient air measurements were carried out to assess external exposure to vapours and aerosols of bitumen. Hydroxylated metabolites of naphthalene, phenanthrene and pyrene were measured in urine, whereas (+)-anti-benzo[a]pyrene-7,8-diol-9,10-epoxide ((+)-anti-BPDE), 8-oxo-7,8-dihydro-2'-deoxyguanosine (8oxodGuo) and DNA strand breaks were determined in blood. Significantly higher levels of 8-oxodGuo adducts and DNA strand breaks were found in both pre- and post-shift blood samples of exposed workers compared to those of the referents. No differences between exposed workers and referents were observed for (+)-anti-BPDE. Moreover, no positive associations between DNA damage and magnitude of airborne exposure to vapours and aerosols of bitumen could be observed in our study. Additionally, no relevant association between the urinary metabolites of PAH and the DNA damage in blood was observed. Overall, our results indicate increased oxidative DNA damage in workers exposed to vapours and aerosols of bitumen compared to non-exposed referents at the group level. However, increased DNA strand breaks in bitumen workers were still within the range of those found in non-exposed and healthy persons as reported earlier. Due to the lack of an association between oxidative DNA damage and exposure levels at the workplaces under study, the observed increase in genotoxic effects in bitumen workers cannot be attributed to vapours and aerosols of bitumen.

Assessing cancer hazards of bitumen emissions – a case study for complex petroleum substances

“…Values for DNA strand breaks and 8-oxodGuo adduct from peripheral white blood cells were like those reported for controls in the Marczynski et al (2011) publication evaluating DNA damage in bitumen exposed workers. The pattern of response for nonsmokers indicated more DNA strand breaks preshift than postshift while more DNA adducts and greater percentage of apoptotic cells were seen postshift.…”

“…This study indicated the potential influence of circadian rhythm on biomarkers. When considered with Marczynski et al (2011), a similar shift-work effect from general occupational exposure was observed, marginally enhanced by bitumen exposure but within the acceptable range of healthy individuals. Pesch et al (2011) and Lotz et al (2016) reported that PAC metabolites in urine of mastic asphalt workers could not be considered specific biomarkers of bitumen exposure in the workplace due to the weak correlation with airborne bitumen exposure levels.…”

Genotoxic changes in peripheral lymphocytes after therapeutic exposure to crude coal tar and ultraviolet radiation

“…The first pathway includes formation of specific PAHs-DNA adducts (oxygen-independent reaction with DNA, type I reaction) (ref. 37 ), the second pathway includes induction of oxidative stress (oxygendependent mechanism, type II reaction) (ref. 38 ).…”

Lymphocyte DNA damage in Turkish asphalt workers detected by the comet assay

“…Asphalt workers showed an elevated level of DNA strand-breaks and oxidative DNA damage in some studies using comet assay (Toraason et al 2001;Cavallo et al 2006;Marczynski et al 2006Marczynski et al , 2011Lindberg Bacaksiz et al et al 2008). In the present study, we found that the workers exposed to asphalt fumes had significantly higher DNA damage than the controls.…”