Quantification of mutagenic/carcinogenic heterocyclic amines, MeIQx, Trp-P-1, Trp-P-2 and PhIP, contributing highly to genotoxicity of river water.

Four mutagenic/carcinogenic heterocyclic amines (HCAs), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido[4,3-b]indole(Trp-P-2) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), in organic extracts obtained by blue rayon hanging method from the Yodo River water were quantified. Blue rayon extracts obtained were separated in two stages of fractionation by reversed-phase high performance liquid chromatography (HPLC), and the quantification of corresponding fractions was performed by HPLC with an electrochemical detector for MeIQx and a fluorometric detector for Trp-P-1, Trp-P-2 and PhIP. The geometrical mean values of MeIQx, Trp-P-1, Trp-P-2 and PhIP in extracts collected at 11 locations from the Yodo River systems were 4.8, 26.9, 37.3, and 11.9 ng/g blue rayon equivalent, respectively. The total amounts of four HCAs accounted for mean 24% of the genotoxicity of blue rayon extracts evaluated by the umu test using an O-acetyltransferase-overproducing strain NM2009.