Exposure to carcinogenic polycyclic aromatic compounds and health risk assessment for diesel-exhaust exposed workers

Abstract

The 15 NTP PACs represent a small but non-negligible part of lung-cancer risk with regard to diesel exposure. From this point of view, the dibenzopyrene family are important compounds to be considered.

Real-time characterization of particle-bound polycyclic aromatic hydrocarbons in ambient aerosols and from motor-vehicle exhaust

“…The theoretical lung-cancer risk due to inhalation of p-PAHs and BC was then calculated by multiplying the B(a)Peq and BC concentrations by the corresponding unit risk factors, here defined as the risk corresponding to a lifetime (70 years per 24-h per day) exposure to 1 µg/m 3 of B(a)Peq or BC. The lifetime unit risk factor estimates considered in this work were obtained from both epidemiological studies and research conducted on rats (Sauvain et al, 2003), and compared reasonably well with those reported by the World The results of these rather simplified risk calculations (Table 3) highlight two important points. First, the lungcancer risk at the Wilmington site is highest during rush hour traffic (at 08:00; Risk[BC]=3.82×10 −5 for the rodentbased estimate to 1.77×10 −3 for the epidemiologic estimate; Risk[p-PAHs]=2.63×10 −7 for the rodent-based estimate to 4.94×10 −6 for the epidemiologic estimate) and lowest in the afternoon (at 17:00, Risk[BC]=5.94×10 −6 to 2.76×10 −4 ; Risk[p-PAHs]=8.59×10 −8 to 1.61×10 −6 ).…”

“…Estimating the potential health risk from these species and comparing the results to those obtained in other metropolitan areas is instructive, despite the large uncertainties involved in these calculations. Following the procedure adopted by Sauvain et al (2003) we determined the lungcancer risk associated with exposure to p-PAHs and BC from diesel combustion particles (DCPs). The most common approach for estimating health-risks posed by multi-component p-PAH exposure is based on the individual compound's po- Slopes and intercepts of all regression equations, and molecular formulas and structures of each individual species are also reported tency equivalence factor (PEF) relative to Benzo (a) pyrene (B(a)p; considered as a toxicological prototype for all other p-PAHs).…”

“…The most common approach for estimating health-risks posed by multi-component p-PAH exposure is based on the individual compound's po- Slopes and intercepts of all regression equations, and molecular formulas and structures of each individual species are also reported tency equivalence factor (PEF) relative to Benzo (a) pyrene (B(a)p; considered as a toxicological prototype for all other p-PAHs). A B(a)P equivalent concentration (B(a)Peq) is calculated by multiplying the individual p-PAH concentrations by the correspondent PEF (Bostrom et al, 2002;Sauvain et al, 2003;Chen and Liao, 2006), and the carcinogenic potency of all considered p-PAHs is then expressed as the sum of each individual B(a)Peq ( B(a)Peq). To simplify our calculations, BC was assumed to be emitted only from DCPs.…”

“…Secondly, the genotoxic risk of the considered p-PAHs does not seem to contribute to a significant part of the total lung-cancer risk attributable to BC (less than 2%). For comparison, Sauvain et al (2003) estimated that the lifetime risk of lung cancer associated with occupational exposure to p-PAHs measured in a bus depot, a truck repair workshop, and an underground tunnel in Lausanne (Switzerland), was 3 to 8% of the total risk attributable to diesel exhaust particles emitted in the summertime. Marr et al (2004) calculated a mean cancer risk level for p-PAHs of approximately 5×10 −5 (a value ∼10 times higher than the highest p-PAH risk estimated in Wilmington) for lifetime exposure to p-PAHs concentrations found along a typical roadway in the Mexico-City metropolitan area.…”

“…These outcomes were then used to establish a correlation between the total p-PAH concentration and the measured PAS signal (from fA to µg/m 3 ). Finally, we determined the approximate theoretical lifetime (70 years per 24-h/day) lung-cancer risk in the Wilmington area due to inhalation of multi-component p-PAHs and BC by following a procedure that considers the benzo (a) pyrene equivalent concentration (B(a)Peq), and BC as a surrogate for diesel combustion particle exposure (Sauvain et al, 2003).…”