Climate change impact on historical contamination – underwater munitions

Contaminants delivered to the marine environment in twentieth century, including those in wrecks and lost or dumped munitions, are the point sources of contaminants to the benthic ecosystems. Climate change related processes, such as oxygen concentration shifts, organic matter delivery and frequency of extreme events may impact those legacy deposits and enhance their release rate to the ecosystem.Chemical and conventional ammunition dumped in the Baltic Sea and the Skagerrak contain a wide range of hazardous substances. Climate related factors may enhance their corrosion rates, causing direct emissions to the surrounding environment and risk of human and wildlife exposure, is increasing. In addition, the degradation processes may lead to increased mobility in unstable environmental settings.Munition constituents are degrading in the environment, producing compounds, of which some are even more toxic than parent substance. Such compounds were identified in sediments next to dumped munitions up to several hundred meters away. Preliminary chemical data indicate exposure of fish in the dumpsite to chemical warfare agents. Studies in a dumpsite of conventional munitions in Kiel Bight reveal an elevated prevalence of neoplastic lesions (liver tumours and pre-stages) in flatfish (dab, Limanda limanda) from the area.Both corrosion rate and biochemical degradation pathways are depending on environmental parameters controlled directly or indirectly by climate factors, therefore historical contamination reemission is considered one of climate change consequences by the Helsinki Comission, which is responsible for the protection of the marine environment of the Baltic Sea area.AcknowledgementsResults presented in this study were partially funded by European Regional Development fund in the frame of MUNIMAP INTERREG BSR project, Horizon Europe Mmine-SWEEPER project and EMFAF MUNI-RISK project. It was also partially funded by the polish Ministry of Science and Higher Education funds for science in years 2022-2027.