The proportions of mutagens among chemicals in commerce

It has been estimated that there are approximately 80,000 chemicals in comm erce, Thus, it is not possible to test all these substances for mutagenicit y and carcinogenicity; it is possible, however, to test or make estimates f rom selected subsets of these chemicals. For example, in the U.S. National Toxicology Program (NTP), 35% of the chemicals tested for mutagenicity in S almonella mere positive, as were 52% of the chemicals tested for carcinogen icity in rodents. In contrast, in the U.S. EPA Gene-Tox database, the propo rtions of chemicals that are Salmonella mutagens is 56%. These and other da tabases may be biased toward positive responses because they generally have been developed to look at specific structural or use classes of chemicals or chemicals suspected of genetic or carcinogenic activity. To address the question of the proportions of mutagens among all chemicals in commerce, a database of 100 chemicals was created from a random selection of chemicals in commerce. These chemicals were tested for mutagenicity in Salmonella and 22% were mutagenic. The mutagenicity of the 46 highest U.S. production org anic chemicals was also compiled; 20% were mutagenic. These values provide a more accurate estimate of the proportions of mutagens among chemicals in commerce than can be derived from published mutagenicity databases. (C) 200 0 Academic Press.