PHOTOTOXICOLOGY .3. COMPARATIVE TOXICITY OF TRINITROTOLUENE AND AMINODINITROTOLUENES TO DAPHNIA-MAGNA, DUGESIA-DOROTOCEPHALA, AND SHEEP ERYTHROCYTES

2,4,6-Trinitrotoluene (TNT) and compounds associated with its producti on are toxic and phototoxic to a wide range of biota. The planarian Du gesia dorotocephala, but not Daphnia magna, metabolized TNT (1 mg/lite r) to 4-amino-2,6-dinitrotoluene (4A; 0.4 mg/liter) and 2-amino-4,6-di nitrotoluene (2A; 0.2 mg/liter). Coexposure to near-ultraviolet (nuv) light enhanced the toxicity of 2A more than that of TNT and 4A. The to xicities of TNT, 4A, and 2A to Du. dorotocephala were all decreased by glutathione (GSH) conjugation. This suggests that all had mechanisms of toxic action involving formation of quinone-GSH conjugates. Dark an d light mechanisms for TNT and 2A depended on GSH conjugation, but the specific mechanisms may be different for each compound. The dark and light mechanisms of toxic action for 4A appeared to be fundamentally d ifferent in that the dark toxic mechanism of action was less dependent on GSH conjugation. Hemolysis studies using sheep erythrocytes showed that the light-enhanced toxic mechanism of action for TNT, 2A, and/or 4A did not involve cellular membrane damage in response to nuv-induce d anions. (C) 1994 Academic Press, Inc.