The mutagenic potency of chrysoidines and bismark brown dyes.

Chrysoidine dyes are used by fishermen to colour bait and recent epidemiological evidence has suggested that this may explain why they are at increased risk of urothelial cancer. In recent years Bismark brown dyes have been used as chrysoidine substitutes. Previous mutagenicity studies on these azo-dyes have examined only one variety of dye and used only one type of activating enzyme. In this study six samples of chrysoidine and three samples of Bismark brown dye have been obtained from chemical suppliers and from angling sources. They have been analysed by n.m.r. spectroscopy to determine whether they contain ring methyl groups. The mutagenic potency of each dye has been assessed by the Salmonella typhimurium/mammalian microsomal mutagenicity assay utilizing the TA100 and TA98 stains. Those dyes with methyl substitutions have been found to be more potent mutagens than their non-methylated counterparts using either human or rat metabolic preparations and irrespective of whether the enzymes have been induced with phenobarbitone.