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A recent study by the GEOMAR Helmholtz Centre for Ocean Research Kiel reveals alarming levels of toxic chemicals from unexploded ordnance (UXO) in the south-western Baltic Sea, estimating approximately 3,000 kilograms of such substances have been discharged into the water. The analysis, covering water samples taken in 2017 and 2018, indicates the presence of these contaminants in nearly all tested samples, with notably higher concentrations observed in the Bights of Kiel and Lübeck. While current levels fall below established health risk thresholds, the findings underscore the pressing need for the removal of munitions to mitigate potential long-term environmental hazards. This research has been published in the journal Chemosphere.
It is estimated that the German Baltic Sea is home to about 300,000 tonnes of unexploded munitions, primarily from intentional disposal following the Second World War. These sites are well-documented, with many munitions visible on the seabed, allowing for precise mapping through the use of underwater robotics. However, the spread of explosive compounds is a significant concern as corrosion increases, with contamination levels predicted to rise unless measures are taken for removal. Compounding these risks, climate change has led to rising temperatures and increased storm activity, which may accelerate the release of harmful chemicals.
Toxins Found in Almost Every Sample
The latest research underscores the long-lasting environmental impact of unexploded munitions in the south-western Baltic Sea. Water samples, particularly from the Bays of Kiel and Lübeck, revealed that nearly every sample contained traces of ammunition-related chemicals. Although most of the detected levels remained well below the safety limits for drinking water and did not exceed toxicological thresholds for marine life, certain concentrations approached concerning levels.
Dr. Aaron Beck, the lead author of the study and a geochemist at GEOMAR, stated, “Unexploded ordnance contains toxic substances such as TNT (2,4,6-trinitrotoluene), RDX (1,3,5-trinitro-1,3,5-triazine), and DNB (1,3-dinitrobenzene), which are released into the seawater as the metal casings deteriorate. These compounds present a direct threat to marine ecosystems and organisms due to their toxic and carcinogenic properties.”
Regional Differences in Contamination
The investigation also revealed regional disparities in contamination levels based on the types of munition discarded. Elevated concentrations of TNT were predominantly found in the Bay of Kiel, while RDX and DNB levels were notably higher in the Bay of Lübeck. Interestingly, most chemicals related to munitions were detected in a dissolved state, rather than attached to sediments or suspended particles.
The researchers approximated that around 3,000 kilograms of dissolved munitions-related chemicals currently reside in the Baltic waters. Without intervention, future contamination is expected to proliferate as the corrosion of metal casings continues, a process estimated to persist for the next 800 years.
A Global Environmental Issue
This study highlights the broader implications of chemical contamination arising from legacy munitions, identifying it as a global concern. The researchers advocate for the designation of dumped ordnance as “historical contaminants of emerging concern,” calling for focused remediation initiatives to tackle the issue effectively.
Dr. Beck noted, “In contrast to diffuse pollution sources, UXO exists in a concentrated and contained form, allowing for its physical removal from the environment.” Germany’s initiatives in munitions clearance could act as a precedent for similar efforts worldwide, providing a pathway to eliminate at least one source of environmental stress from marine ecosystems.
About: Munitions Clearance Pilot Project
To address the legacy of unexploded ordnance, the German government has launched a pilot project aimed at recovering and responsibly disposing of these hazardous remnants. This initiative represents the first global effort of its kind, supported by a budget of 100 million euros. The pilot operation began in autumn 2024 in the Bay of Lübeck, with plans to leverage collected data to create an autonomous clearance platform capable of treating and incinerating munitions at sea.
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