In the past century, around 1.6 million tons of conventional and 250 000 tons of chemical warfare agents (CWA) were dumped in the coastal waters of the North and Baltic Seas. Most of them came from the armories of the German army and were dumped in the sea after the end of World War II under the supervision of the Allies. Bombs, grenades shells, sea mines, weapons and cartridges were sunk. In addition, drums and containers filled with chemical warfare agents or chemicals that were needed for the production were sunk.
The largest dumping areas for chemical warfare agents are located outside German territorial waters in the Skagerrak (Norway and Sweden, 200,000 tons) and in the Baltic Sea near Bornholm (Denmark) and in the Gotland Basin (Sweden). Around 30,000 tons of chemical warfare agents have been dumped in the Baltic Sea, including around 10,000 tons in the Bornholm Basin alone. In addition, thousands of tons of conventional munition and weapons are rotting in several areas belonging to German territorial waters. A share of 300,000 tons lies in the Baltic Sea, especially in the Bay of Kiel and Lübeck, while around 1.3 million tons of munitions are still suspected in the North Sea. Areas off Spiekeroog and Wangerrooge as well as the Jade Estuary are affected, but ammunition has also been dumped around Helgoland.
Today, the condition of old ammunition varies. Some cartridges, grenades and mines are still ignitable, while in others the casing has almost completely decomposed. When the ammunition casings decay, toxic components of the explosive as well as their degradation products are released. We are seeking to answer the question whether and to what extent the former components of the ammunition are taken up by marine organisms and whether the organisms suffer adverse health effects as a result of contact with the warfare agents and explosives. First results show that wherever munitions are located in the water, substances from the munitions are also detectable in the surrounding water and sediment. These substances, in turn, are ingested by both mussels and fish. Traces of the substances can subsequently be detected in the tissue. In laboratory experiments, there is also increasing evidence that contact with ordnance and explosives is harmful to the organisms involved.
This finding, in turn, means that dumped World War II munitions in the North and Baltic Seas still pose a much greater threat to the biotic communities of both seas than was previously assumed. According to all experts, this problem is likely to increase rather than decrease in the future, as corrosion continues unabated and more and more potentially harmful substances are released into the water.