By Rachel Ehrenberg, Science News
ANAHEIM, Calif.—As if enemy fire, IEDs and suicide bombers weren’t enough, U.S. soldiers in Iraq also must contend with air that’s laden with heavy metals and lung-ravaging particles, researchers reported March 30 at the spring meeting of the American Chemical Society. Exposure to particles of the size collected in the study is of special concern because it can lead to chronic respiratory infections, asthma and elevated risk of cardiovascular problems.
Air samples collected over 90-minute intervals at several sites in Iraq since 2008 contained fine particulate matter, dust, lead, aluminum and other metals in quantities that frequently exceed U.S. air quality standards, graduate student Jennifer Bell of the Geophysical Institute at the University of Alaska Fairbanks reported.
While concentrations varied daily, typical concentrations of lead particles ranged from 0.6 to 1 microgram per cubic meter of air, Bell and her thesis adviser Catherine Cahill found. That's at least four times greater than exposure standards set by U.S. national air quality standards. During one dust storm, airborne aluminum concentrations exceeded 1,400 micrograms per cubic meter. Chronic exposure to more than 65 micrograms per cubic meter of any type of particle in this size range may increase risk for health problems.
The noxious air likely results from a combination of natural and man-made sources, said Bell. Iraq has a number of clay deposits, sandstone foothills and other geologic features containing zinc, lead and silicate minerals that get swept up and carried in enormous dust storms that blanket the region on average more than 20 times a year. Leaded gasoline is still widely used in Iraq, which along with open trash burning, oil fires and debris from explosions makes naturally dusty air even worse.
“My major concern would be for potential long-term health ramifications,” said Robert Brook, a specialist in cardiovascular effects of air pollution at the University of Michigan Medical School in Ann Arbor. Fine particulate matter—particles smaller than 2.5 micrometers—can evade hairlike projections in the nose and trachea that trap larger particles. Particles of this size class can penetrate deep in the lungs and are the most strongly linked to adverse health effects, said Brooks, who was not involved in the research.
Deployment to Iraq was associated with a significantly higher risk of asthma compared with stateside duty, scientists reported last year. Both soldiers and Department of Defense contractors report increased wheezing, coughing, allergy symptoms and chest pain and tightness during deployment compared with predeployment.