Chlorination of harman and norharman with sodium hypochlorite and co-mutagenicity of the chlorinated products

Harman and norharman are widely distributed in the environment and conseque ntly contaminate in domestic waste-water. It has been reported that they ha ve co-mutagenic activity in the presence of non- mutagenic aromatic amines such as aniline and o-toluidine with S9 mix. When these beta -carbolines we re treated with sodium hypochiorite under mild conditions, chlorinated deri vatives were produced. Among them, 6-chloroharman and 6-chloronorharman sho wed much more potent co-mutagenic activities than harman and norharman in t he presence of o-toluidine toward Salmonella typhimurium TA98 with S9 mix. These results suggest that the chlorination of harman and norharman occurs during disinfection at the sewage plant to produce potent co-mutagens that contaminate river water. (C) 2000 Published by Elsevier Science B.V.