Formation and identification of azaarene transformation products from aquatic invertebrate and algal metabolism

The metabolism of two azaarenes, viz. acridine and phenanthridine, by aquat ic organisms was studied in short-term and chronic laboratory tests. The id entity of metabolites observed in the test waters was investigated with dif ferent analytical methods, including HPLC, GC and hyphenated LC- or GC-MS. The Zebra mussel (Dreissena polymorpha), one green alga species (Selenastru m capricornutum) and periphyton or bacteria transformed acridine into 9[10H ]-acridinone. Phenanthridine was transformed into 5[6H]-phenanthridinone by midge (Chironomus riparius) larvae. The findings indicate that closely rel ated isomers may undergo species-specific biotransformation. It was conclud ed that keto-metabolites are major products in the aquatic fate of benzoqui nolines, which may be overlooked in the risk assessment of parent compounds . This study illustrates the typical problems with, as well as the potency of, chromatographic methods in the elucidation of metabolic routes of organ ic contaminants. (C) 1999 Elsevier Science B.V. All rights reserved.