Overvåkning av tungmetallforurensning ved Forsvarets destruksjonsanlegg for ammunisjon i Lærdal kommune

In Øyradalen south of Lærdal the Military has a destruction facility for munitions. This area was established in 1976, and has since been used by the military for demolition of munitions. Ammunition with calibre greater than 20 mm is demolished here. In addition, the military has a facility for destruction of gunpowder and small arms munitions in Tønjumdalen. The destruction of such munitions takes place in an incinerator connected to a treatment plant. The facility in Tønjumdalen has been in use since 1989. From 1991 until today soil samples from Øyradalen have been analysed to monitor the concentration of heavy metals. The results show that there in particular is a deposition of copper in the demolition area, but also some lead has been deposited. The highest concentrations of copper are registered in the late 1990s. Since then, it appears that the level of copper has decreased, although the amount of demolished munitions has not been reduced. This is probably due to changed demolition procedures, which involve removal of the driving band before the munitions are demolished. In several sample points in the demolition area throughout the monitoring period, it is detected concentrations of copper more than 1000 mg/kg. The average concentration of copper in the demolition area was 724 mg/kg in the autumn of 2007. Based on the current use of the area, this will pose no human health risk. The area will not be suitable for food production or livestock. It is not very likely that grazing animals stay in the area for a very long period of time, but grazing animals can be attracted to the area by other factors. The area can therefore pose a certain risk for grazing animals. The level of lead in the demolition area will not pose a risk to human health or grazing animals. Normal concentrations of both total organic content and nitrate have been measured in the river Nivla. It has not been observed any difference in the concentration of these two parameters downstream compared to upstream the demolition area. Throughout the monitoring period, the concentration of nitrite in water samples downstream the demolition area has not exceeded the detection limit. In 1991 and from 1999-2003 samples of soil has been analysed for monitoring the contamination of heavy metals. The result shows an increasing level of lead in the area close to the destruction facility in Tønjumdalen, while other heavy metals show low concentrations. Hence, lead from small arms munitions seems to be deposited. Based on the current land use, the level of lead does not pose any risk for human health. For grazing animals the area may pose a risk. To assess the health risk for military personnel working in these areas it is necessary to perform an occupational health examination. This is expected to be handled by local HMS-work. Based on the results from the monitoring data, a new monitoring program for both Øyradalen and Tønjumdalen is recommended.