Simulation of TNT leackage in sea environment

After World War II, since no destruction plant for explosives was available, explosives were dumped in various places in Sweden. Between 1940 and 1968 munitions were dumped in lakes, abandoned mineshafts and sea areas. Presently, the Swedish Armed Forces is investigating security risks and ecological risks connected with the dumped obsolete ammunition. TNT, which is classified as an environmental hazardous compound, is the main component of the explosives that has been dumped. In this context and with the knowledge that TNT is fransformed in nature, experiments have previously been conducted to mimic leakage of TNT in lake environment. However, deep-lake and deep-sea environments are substantially different. Therefore, FOI has in the present report, by order of the Swedish Armed Forces, mimicked leakage of TNT in sea environment. Sediment and water from three different sea dumping locations were collected. From the Baltic Sea, one location with aerobic and one location with anaerobic sediment were selected. From the western sea only one aerobic sediment location was chosen. The results of this study showed that TNT was rapidly transformed to other metabolites also in sea environment. The metabolites were adsorbed firmly to the tested sediments, but lower amounts were bound under anaerobic conditions. Water-soluble metabolites originating from TNT were primarily formed during anaerobic conditions but the long-term leakage was for all sediments lower than 10 % of the total amount bound to sediment.