DNA adducts derived from diesel emissions - Assessment of genotoxic potency in vitro and human exposure monitoring

Diesel particle extracts, which originated from three different diesel fuel s, were used to study the activation of polycyclic aromatic hydrocarbons (P AHs). DNA adducts were analyzed in vitro calf thymus, human skin tissue cul ture and in lymphocytes isolated from diesel exposed workers. Direct-acting mutagens (e.g. nitro-PAHs) measured by Ames test were compared with DNA ad ducts formed in vitro by nitroreductive xanthine oxide enzyme. PAH-DNA addu cts were analyzed by P-32-postlabeling, and when characterizing adducts fro m skin DNA, a solid-phase micro extraction (SPME) method was developed for sample preparation before HPLC analysis. A good accordance between mutageni city and DNA adducts showed that the three extracts contain higher amounts of direct-acting PAHs than the PAHs needing S9 activation. Skin DNA adducts demonstrated two-fold differences between the tissue cultures. P-32-postla beling and HPLC analysis did not confirm the identity of skin DNA adducts w ith the BPDE-DNA standard. The pilot study on 13 diesel exposed bus garage and waste collection workers showed low levels of PAH exposure (<50 ng/m(3) ) and lymphocyte PAH-DNA adducts less than 2 adducts/10(8) nucleotides.