Effects of climate change on marine dumped munitions and possible consequence for inhabiting biota

Marine environments are contaminated with enormous amounts of warfare agents due to military activity and exercise, and the disposal of unused ordnance. Due to corrosion of munition shells, substances are leaking from the warfare materials into the environment. It has to be expected that climate change will influence munition corrosion and distribution of their content. Although there is no doubt about the principle toxicity of many of the munition compounds, including their transformation/degradation products, the impact of munition compounds on marine environments, including their biota are yet only at the beginning to be understood. Recently the intake of munition compounds has been confirmed in mussels and fish collected from contaminated areas. It has become clear that dumped munitions are a continuous source of toxic substances leaking into the environment and that ongoing corrosion will worsen the problem. The present review intends to evaluate the available literature on how climate change might influence the contamination of marine environments and inhabiting biota with munition compounds. Direct testing (or modelling) of climate change scenarios in the context of the marine munition problems has yet not been undertaken. Nevertheless, it can be predicted that climate change effects such as rising temperature and higher frequencies of extreme weather events will accelerate the rates at which disposed ordnance corrodes and consequently accelerate the rate at which munition compounds are leaking out. Climate change will cause elevated stress to biota, ranging from temperature stress and lower availability of oxygen to shifts in salinity and pH. In combination, elevated release of munition related compounds and elevated environmental stress, will put biota under threat, in particular in areas with high munition contamination and limited water exchange, such as the Baltic Sea. On a positive side, biodegradation of organic munition compounds by biota and microorganisms is likely to be accelerated with rising temperature.