Does dumped munitions harm fish and shellfish? – an assessment in four dumping grounds

FFI has investigated the content of munition-related compounds in fish and shellfish in dumping grounds for munitions, in order to assess the bioaccumulation and risk at consummation. Fish and shellfish were caught in the dumping grounds localized in Malangen, Skjerstadfjorden, Botnfjorden/Leirfjorden and Øygarden. These areas were selected as they coincides with active fishing areas and represent much of the coastline from north to south. This is the first major study of biota in dumping grounds for munitions in Norway and is performed in the research project “Mapping of war remnants and dumped munitions” at FFI. The Institute of Marine Research (IMR), in collaboration with local fishing vessels, has been responsible for catching fish and shellfish in the dumping grounds. IMR has also carried out chemical analysis of metals in biota. Eurofins TestAmerica has carried out the chemical analysis of explosives. The study has revealed that biota is exposed to explosives. The dumped munitions has thus corroded in a way, which make explosives in the munitions available to biota. The study also shows that in some area there may be exposure to lead from dumped munitions. Explosives were found in the biota from all four dumping grounds examined. Several explosives and decomposition products were detected, which shows that different types of munitions have been dumped. The highest concentration of explosives in the biota was observed for nitroglycerin (20 mg/kg wet weight) in the northern stone crab mustard caught in the Øygarden dumping groundd. Explosives were generally not detected in fish muscle, claw meat or shrimp meat. This means that the content of explosives in marine biota to a lesser extent poses a health risk when fish and shellfish caught in dumping grounds for munitions are consumed. Calculations that have been made indicate that the maximum tolerable daily intake of explosives is higher than the actual intake of fish and shellfish. The lowest intake is calculated for northern stone crab mustard, where intake should not exceed 0.4 grams/day for adults. The level of mercury in the tusk muscle is higher than the limit value (0.5 mg/kg ww). However, it is not abnormal that there are high concentrations of mercury in the tusk muscle along the Norwegian coast, and dietary advice has been introduced in some areas. Although there will be mercury in munitions, it will be small amounts. It is therefore considered less likely that the high concentrations of mercury are directly related to the munitions dumping grounds, but rather related to the general pollution of mercury along the Norwegian coast. The study suggests that biota is exposed to lead from munitions in some dumping grounds. However, the level is below the limit value for lead in fish (0.3 mg/kg ww) and shellfish (0.5 mg/kg ww). FFI recommend that prohibition zones for fishing in and around dumping grounds for munitions are established. This is mainly related to the safety risk associated with dumped munitions. Munitions can tangle in fishing gears and cause a detonation with consequent damage to humans and material. There is also a small risk associated with the consumption of fish and shellfish caught in dumping grounds.