Mutagenicity of constituents identified in pulp and paper mill effluents using the Salmonella/mammalian-microsome assay.

About 300 compounds have been reported in the literature as constituents of pulp-mill effluent. Previously, in our screening program, 10 resin acids identified in effluent were examined for potential mutagenicity in the Salmonella/mammalian-microsome assay. Neoabietic acid was the only resin acid which was found to be mutagenic. Now, a program to screen for mutagenicity of 48 additional compounds, belonging to chemical classes of chlorinated aliphatic and aromatic hydrocarbons, phenols, aldehydes, quinones, and carboxylic acids, has been completed. Only 2 of these compounds, tetrachloropropene and pentachloropropene, were found to be mutagenic, showing dose-related increases in His+ reversion mutations, in the standard Salmonella test. Metabolic activation with a preparation of Aroclor 1254-induced liver homogenate (S9) greatly reduced the mutagenic responses of these 2 compounds. Modifications of the Salmonella test for volatile mutagens enabled the detection of the mutagenicity of 3 additional chlorinated aliphatic hydrocarbons dichloromethane, dichloroethane and trichloroethane.