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Direct-acting mutagens in automobile exhaust
Cancer Letters
|July 1, 1978
Summary
City air contains direct-acting mutagens, primarily from automobile exhaust, that are harmful without liver activation. Research identified these mutagens and synthesized 6-nitrobenzo[a]pyrene, confirming its potent mutagenic activity.
Area of Science:
- Environmental Chemistry
- Toxicology
- Chemical Mutagenesis
Background:
- Urban air contains particulate matter with mutagenic chemicals.
- Mutagens in residential urban air are often direct-acting, not requiring liver enzyme activation.
- Automobile exhaust is a suspected source of these direct-acting mutagens.
Purpose of the Study:
- To investigate the source and nature of direct-acting mutagens in urban air.
- To determine if automobile exhaust is the primary source of these airborne mutagens.
- To identify specific mutagenic compounds in automobile exhaust.
Main Methods:
- Correlation analysis of mutagenic activity with air lead content.
- Analysis of mutagenic compounds in automobile exhaust samples.
- Testing of fuel, unused motor oil, and used motor oil for mutagenicity.
- Synthesis and mutagenicity testing of 6-nitrobenzo[a]pyrene using the Ames Salmonella typhimurium assay.
Main Results:
- Mutagenic activity in urban air correlated with lead content.
- Direct-acting mutagens were identified in automobile exhaust samples.
- These mutagens were absent in fuel and unused oil but present in used oil.
- Synthesized 6-nitrobenzo[a]pyrene demonstrated potent, direct-acting mutagenicity.
Conclusions:
- Automobile exhaust is a significant source of direct-acting mutagens in urban air.
- Nitro-substituted polycyclic aromatic hydrocarbons, like 6-nitrobenzo[a]pyrene, are likely contributors to the observed mutagenicity.
- These findings highlight the health risks associated with air pollution from vehicle emissions.