Experimental studies in rat lungs on the carcinogenicity and dose-response relationships of eight frequently occurring environmental polycyclic aromatic hydrocarbons.

The biologic activity of eight highly purified polycyclic aromatic hydrocarbons (PAH) widely distributed in the human environment was tested in the respiratory tracts of rats. These studies were performed for the examination of carcinogenic activity of the compounds and determination of a dose-response relationship. The lung implantation method was used in 3-month-old female OM rats. A dose-response relationship was obtained for benzo[a]pyrene (BaP), anthanthrene (ANT), benzo[b]fluoranthene (BbF), indeno[1,2,3-cd]pyrene (IND), benzo[j]fluoranthene (BjF), and benzo[k]fluoranthene (BkF). Benzo[e]pyrene and benzo[ghi]perylene showed no tumor-producing effect in this system when given at doses of 5 mg. The histologic and mathematical evaluations indicated that the investigated compounds had distinct carcinogenic potencies. After probit analysis of the results, the carcinogenic potencies of PAH investigated in the lung implantation model rank as follows: BaP, 1.00; ANT, 0.19; BbF, 0.11; IND, 0.08; BkF, 0.03; and BjF, 0.03.