The objective of this work was to characterize the effluent originating from a Brazilian TNT production industry. Analyses were performed using physical, chemical, spectroscopic and ecotoxicological assays, which demonstrated that the effluent had a significant pollution potential, mainly due to the low pH and high concentration of TNT (156 +/- 10 mg L-1). The results also demonstrated that the effluent presented significant acute toxicity, and could cause countless damages if released into the receiving body without being adequately treated first. The observed pollution potential justifies studies to evaluate treatment technologies or recover the residue generated in the TNT industry. (C) 2008 Elsevier B.V. All rights reserved.