Agradecimentos: The authors are grateful to Dr. Avram Gold and Dr. Zhenfa Zhang from the University of North Carolina at Chapel Hill, U.S.A. for kindly providing the B[j]A standard for the present study. This work was supported by Stockholm University, Karolinska Institutet, and the Swedish Research Council Formas (R&D project No. 2012-478) Ver menos

Abstract: Benz[j]aceanthrylene (B[j]A) is a cyclopenta-fused polycyclic aromatic hydrocarbon with strong mutagenic and carcinogenic effects. We have identified B[j]A in air particulate matter (PM) in samples collected in Stockholm, Sweden and in Limeira, Brazil using LC–GC/MS analysis. Determined concentrations ranged between 1.57 and 12.7 and 19.6–30.2 pg/m3 in Stockholm and Limeira, respectively, which was 11–30 times less than benzo[a]pyrene (B[a]P) concentrations. Activation of the DNA damage response was evaluated after exposure to B[j]A in HepG2 cells in comparison to B[a]P. We found that significantly lower concentrations of B[j]A were needed for an effect on cell viability compared to B[a]P, and equimolar exposure resulted in significant more DNA damage with B[j]A. Additionally, levels of ?H2AX, pChk1, p53, pp53, and p21 proteins were higher in response to B[j]A than B[a]P. On the basis of dose response induction of pChk1 and ?H2AX, B[j]A potency was 12.5- and 33.3-fold higher than B[a]P, respectively. Although B[j]A levels in air were low, including B[j]A in the estimation of excess lifetime cancer risk increased the risk up to 2-fold depending on which potency factor for B[j]A was applied. Together, our results show that B[j]A could be an important contributor to the cancer risk of air PM Ver menos