Distribution and biliary excretion products of di-2-ethylhexyl phthalate in rainbow trout.

After 24-hr exposures of rainbow trout to 0.5 ppm of di-2-ethylhexyl [14C]phthalate, one-half of the radioactivity present in the fish was localized in the bile. The bile was pooled and fractionated by selective solvent extraction before and after beta-glucuronidase hydrolysis. Individual radioactive compounds were further separated and characterized by thin-layer chromatography. Gas chromatography-mass spectrometry was used to confirm the results of thin-layer chromatographic analysis. These procedures demonstrated that bile contained a number of DEHP metabolites, but only about 1% of unchanged DEHP. The major metabolite, mono-2-ethylhexyl phthalate glucuronide accounted for 72% of the total bile radioactivity. The remaining bile radioactivity was found to be present as phthalic acid glucuronide, mono-2-ethylhexyl phthalate and two partially characterized polar metabolites.