Abstract |
In the late 1970's, the U.S. Environmental Protection Agency assessed the impact of the diesel-powered passenger automobile on the current fleet of gasoline powerplants. Little was known regarding the toxicological effects of exposure to diesel emissions, the components of diesel exhaust, or their physical characteristics. Although a number of epidemiological studies had been completed, none showed a causal relationship between exposure to diesel exhaust and an increased incidence in lung cancer. There were no well-conducted studies in experimental animals which indicated a cancer hazard by any route of administration. A broad-range research program was initiated to study the mutagenic and carcinogenic effects of diesel engine emissions and other related complex mixture samples. These studies featured a combined approach of analytical chemistry, genetic toxicity bioassay, and tumor bioassay to fully characterize both the complex mixtures themselves as well as individual components which might be responsible for biological activities. The paper summarizes the approaches taken and the results obtained and cities previously published data. Also presented are some current research efforts aimed at furthering our knowledge of these relationships. |