Part I: Mutagenicity and Other Genetic Effects

These data Indicate Lhat in this instance 1-NP and the DNPs did not contribute significantly to the induction of skin tumors in mice. Of the compounds detected. BoP was the major contributor to the tumorigenic potency in the Nissan extract (Table C.3). Benzo[b]fluoranthene (BbF) and benzo[;lfluoranthene (BjF) were also significant contributors. ln the case of the Volk!Magen extract. the relatively low concentration of BoP relative tootherPAHs skewed the contributions ofBbF, BjF, and fluoranthene so that they were at least as significant as BaP in terms of tumorigenicity. ft is important to note that DBAs and DBPs wore not analyzed in these extracts. Savard and coworkers (1992) have performed a detailed chemical analysis of a National Institute of Standards and Technology (NIST) standard reference material particulate matter (SRM 1650) from a heavy-duty diesel engine (May et al. 1992). Estimates of the relative tumorigenic contributions of PAHs and nitro-PAHs are presented in Table C.4. BenzoUlfluoranthene made a significant contribution to the preweanling mouse assay, but had only a slight offect in the Jung implantation assay.