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Member Research and Reports

Member Research and Reports

Arizona: A Pilot Study of Legionella Pneumophila as a Health Hazard to Miners

Legionella pneumophila (L. pneumophila), the causative agent of legionellosis, is an aquatic bacterium that grows in warm water. Humans are only presented with a health risk when aerosolized water containing L. pneumophila is inhaled.

In mining operations, aerosolized water is used as dust control and as part of the drilling operations, a currently ignored exposure route. A pilot study led by Ms. Valerie Madera-Garcia, a doctoral student in the epidemiology program at the University of Arizona Mel and Enid Zuckerman College of Public Health and colleagues, characterized L. pneumophila concentrations in the mine’s non-potable water and the relationship between L. pneumophila and chlorine concentrations. These concentrations informed a quantitative microbial risk assessment (QMRA) model to estimate the infection risk to miners exposed to aerosolized water containing L. pneumophila.

Fourteen water samples were collected from seven locations at a mine and analyzed for temperature, pH, chlorine, and L. pneumophila serogroup. Most samples (93 percent) tested positive for L. pneumophila cells. The faucet from the sprinkler system at the entrance to the underground mine levels showed the highest concentration of L. pneumophila. Disability adjusted life years were estimated in the QMRA model and showed that the risk for all miners was significantly lower with the ventilation system on than when the system was off.

The research showed that the use of a ventilation system at the entrance to the underground mine level of the mine reduced the risk of infection with aerosolized L. pneumophila.

The study was published in the open access journal Water.

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