War relict munition at sea: Depuration kinetics of trinitrotoluene (TNT) and its metabolites in exposed blue mussels (Mytilus edulis, L.)

Franziska Isabell Binder¹Romina Marietta Schuster¹Tobias Hartwig Bünning²Jennifer S. Strehse²Mike Brockmann³Rainer Herges³Edmund Maser²Matthias Brenner^1*

• ¹Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), Bremerhaven, Germany
• ²Institute for Toxicology and Pharmacology for Natural Scientists, Faculty of Medicine, University of Kiel, Kiel, Schleswig-Holstein, Germany
• ³Otto Diels Institute for Organic Chemistry, Faculty of Mathematics and Natural Sciences, University of Kiel, Kiel, Schleswig-Holstein, Germany

Explosives released by dumped warfare material pose a threat to the marine environment and can enter the marine food web. 2,4,6-Trinitrotoluene (TNT) is one of the most used explosives in munitions and therefore of special interest. To test the uptake, depuration and potential bio-transformation of TNT, common blue mussels (Mytilus edulis) from the German North Sea were exposed to different TNT concentrations in two laboratory experiments (first experiment: 48 hours exposure to TNT concentrations of 0 mg/L, 0.625 mg/L, 1.25 mg/L and 2.5 mg/L. Second experiment: 24 hours exposure to 0 mg/L and 5 mg/L deuterated TNT) followed by recovery phases in clean artificial seawater (first experiment: 60 hours recovery. Second experiment: 12 hours recovery). Water samples and mussel soft bodies were analysed for TNT and its metabolites 2-amino-4,6-dinitrotoluene (2-ADNT), 4-amino-2,6-dinitrotoluene (4-ADNT) and 2,4-diamino-6-nitrotoluene (2,4-DANT) by using GC-MS/MS techniques. Results showed a continuous up take of dissolved TNT during exposure and a rapid depuration during the recovery phase, independent of the original TNT exposure concentrations. Further, evidence for the bio-transformation of TNT are shown by the presence of labelled ADNTs both in mussel soft bodies analysed within the recovery phase and in water sampled during the recovery phase. Overall, 57 to 76% of the detected measured concentration was bio-transformed within the first four hours after the exposure.