Risk Assessment of Sea Dumped Conventional Munitions

Huge amount of ammunition, both conventional and chemical weapons, have been dumped in the oceans of the world during the last century. In particular, large amounts of ammunitions were dumped in the sea after the Second World War. It has been estimated that between 750000 and 1.5 million metric tons of conventional ammunition was dumped along the German North Sea cost [1] . In Norway, an estimate of approximately 200000 metric tons of ammunition were dumped after the Second World War. These figures do, not include disposal of ammunition in the two northernmost counties in Norway, which probably represented a similar amount [2]. Dumping in the oceans as well as in lakes and rivers was regarded as an accepted measure to dispose redundant ammunition, it was fairly efficient and considered as secure. In addition, there are large amount of UXOs across the world from military activity [3]. Although less in volume, ammunitions are still left behind as unexploded materials in waters during training. Wastewater, soils, groundwater, and surface waters have become contaminated with a variety of energetic compounds arising from ammunition manufacture and processing [3–6]. Less is known about environmental spread of energetic compounds in dumped ammunition, but some concerns are raised that explosives and other toxic compounds from dumped ammunition can leak out to ambient water and sediments and expose various organisms. The energetic compounds in dumped ammunition were originally sealed into the bombshells and are in principle not subjected to considerable leakage. Leakage will first occur when bombshell is broken and the energetic compounds come into contact with water and air. The bombshells, which are made of different alloys of metals, will after dumping start to corrode and sooner or later the explosives inside will be exposed. The problem of leakage of explosives from dumped ammunition appears to be greater in seawater than in fresh water, due to a higher corrosion rate [2] . Bearing in mind that large amount of dumped ammunition have been exposed to weathering for almost a century in saline water there are reasons to believe that leakage will increase significantly within a relatively short time frame. Several studies have demonstrated the toxicity of energetic compounds on aquatic organisms [7–9]. In spite of the considerable amount of explosive residues that are dumped in the environment there are very little knowledge about the extent of and the potential effects they might have on both freshwater and marine organisms. Based on current knowledge it cannot be excluded that dumped conventional ammunition may pose a future threat to the environment. In the future there will probably be an increased pressure to take measures on contaminated sites both to protect the environment and economic interests, such as the aquaculture industry. This will require applicable site specific methods for risk assessment. The current review discusses approaches for the calculation of screening benchmarks or safe environmental levels of energetics from dumped ammunition for aquatic organisms, with emphasis on benthic organisms. Strategies for risk assessment of dumped ammunition will be suggested. In addition a brief overview of the compounds in dumped Abstract : Energetic compounds from dumped ammunition are toxic to aquatic organisms. Leakage of ammunition residues will occur when the bombshells are broken and the energetic compounds come into contact with water. The munitions compounds have a complex behavior in the environment, particularly in the sediment-water phase, and the calculation of safety levels are dependent on choice of methodology. Estimated sediment quality benchmark levels combined with multi-increment sampling strategy provide the most proper tool for performing ecological risk assessment at a dump site. Dumped munitions may be located in areas, where shellfish, invertebrates, and benthic or pelagic fish are consumed by humans. A monitoring program for early warning of potential contaminants in the vicinity of fish farms could be conducted by passive samplers for explosives. Further development of both sample procedures and analytical methods to increase the quality of the chemical analyses are encouraged.