THE UNSEEN CASUALTIES OF URBAN WARFARE – CELLULAR INJURY INDUCED BY PARTICLE INHALATION IN THE WAR on TERROR

The focus of this study is on the role of particulate matter in the development of lung illnesses of soldiers deployed in Iraq and Afghanistan. Of the soldiers who develop lung illnesses, the majority have adult onset asthma, while others have constrictive bronchiolitis. These types of diseases are inflammatory based. Therefore it is important to evaluate if the soils induce the generation of reactive oxygen species (ROS) or up-regulate cellular ROS (toxicity versus mutagenicity). Furthermore, the chest x-rays of these soldiers do not show significant particulate accumulation, which may be explained by particle dissolution, ROS generation, and subsequent disease development.

The origins of particulate exposures in an urban warfare setting, include, but are not limited to: natural minerals, building debris, and particulates generated by ammunition explosions. While some soldiers know their exposure source, many do not. However, one of the constant contributions is the exposure to natural soil dust, often at extreme exposure burdens. Soil dust is a complex mixture of mineral constituents, organic matter, as well as microbes. In this study we focused on the possible role of the mineral constituents in generating ROS. Besides dust collected in Iraq and Afghanistan, we also studied inorganic model systems and standard soils for comparison.

Soils from Iraq and Afghanistan were characterized using X-ray diffractometry, X-ray fluorescence spectroscopy, and scanning electron microscopy. The dominant mineral components are calcite and quartz. The dust has several weight per cent iron and less than one weight per cent manganese. Because iron and manganese can promote the formation of ROS, a model system with calcite, quartz and varying amounts of iron and manganese was studied in detail. An array of cellular and acellular assays, largely developed in our group over the last five years, were used to evaluate the ability of the dust, standard soils, and model systems to generate ROS. The initial results show that the dust from Camp Victory in Iraq promotes the up-regulation of ROS in epithelial cells, but more experiments will be conducted over the next months to confirm these results.