A/HRC/5/5 page 9 17. In today’s armed conflicts, facilities producing and transporting electricity are regularly targeted. The main environmental cause of concern about the targeting of those facilities is the destruction of transformers, resulting in the leakage of transformer oil which contains polychlorinated biphenyls (PCBs). When destroyed in air strikes, anything from a few to several dozen tons of PCB can leak from transformers. Leaking transformer oil can result in the contamination of the soil, air, rivers and groundwater.22 PCBs are known to have serious health effects on humans, especially in the case of sustained high-level exposure. They are classified as probable human carcinogens and can cause non-cancer-related health problems such as a reduced functioning of the immune system, muscle weakness, skin changes and low birth rates.23 18. Another area of concern in recent armed conflicts has been the use of depleted uranium munitions. Because of its density, depleted uranium is used in both munitions and defensive armour. However, depleted uranium is a radioactive toxic heavy metal and can contaminate the environment upon impact. Although recent studies24 conclude that the radioactive danger is very limited, potential problems caused by heavy metal seeping into the ground and groundwater remain. Contamination resulting from the use of depleted uranium munitions will generally be limited to the immediate vicinity of the impact site and as such will not present a problem for the local population. However, if used in densely populated areas or if the contamination caused by depleted uranium is dispersed in the environment, people living in affected areas may inhale contaminated dust or consume contaminated food and drinking water.25 Indeed, if there is heavy firing of depleted uranium rounds in one area, concentrations of uranium in the groundwater may exceed World Health Organization (WHO) limits. Children can potentially be most affected, as they present the risk of ingesting contaminated soil while playing. The toxicity of uranium can affect mainly the kidney and its radioactivity can, in rare cases of serious exposure, present an increased risk of cancer. Although the studies referred to above concluded that the use of depleted uranium munitions will probably not have a major impact on the health of the general population, nothing is known about the long-term effects of exposure to contaminants contained in those munitions. 19. Herbicides are an additional type of dangerous product that have been deliberately released into the environment during armed conflict. Parties to armed conflicts have used herbicides for two main reasons. First, using defoliants with the objective of denying forest cover to enemy forces. The best known and most documented example of this has been the use of so-called 22 UNEP, The Kosovo Conflict - Consequences for the Environment and Human Settlements (1999), p. 39. 23 United States Environmental Protection Agency, PCBs and Human Health, Hudson River PCBs http://www.epa.gov/hudson/humanhealth.htm. 24 UNEP, Depleted Uranium in Serbia and Montenegro, Post-Conflict Environmental Assessment (2002); UNEP, Depleted Uranium Awareness Leaflet. 25 WHO, Depleted Uranium, Fact sheet No. 257.