What caused the increase in Legionnaires' disease in Flint, Michigan?

The increase in reported Legionnaires’ disease in Flint from June 2014 to November 2015 is directly linked to the switch to corrosive Flint River water. This water was 8.6 times more corrosive than Detroit water, releasing more iron—a key Legionella nutrient—and causing rapid disinfectant decay. Higher water temperatures in the Flint River also contributed to an environment conducive to Legionella growth.

How did the Flint River water's corrosivity impact Legionella risk?

The Flint River water was 8.6 times more corrosive than Detroit water, leading to increased iron release, which is a critical nutrient for Legionella bacteria. This corrosivity also caused disinfectants to decay more rapidly, reducing their effectiveness in controlling bacterial populations. These factors created an environment within the distribution system highly favorable for Legionella proliferation.

What specific water quality changes in Flint promoted Legionella growth?

The Flint River water was significantly more corrosive, releasing iron—a key Legionella nutrient—and causing disinfectant to decay rapidly. Additionally, the Flint River water was 0.8–6.7 °C warmer in summer months, exceeding the minimum Legionella growth temperature of 20 °C more frequently (157 days per year compared to Detroit's 63 days). These combined factors created an ideal environment for the bacteria to thrive.

Were water main breaks linked to Legionnaires' disease in Flint?

Yes, the corrosive Flint River water led to 1.3–2.2 times more water main breaks in 2014–2015 compared to 2010–2013. Such disruptions to the distribution system have been associated with outbreaks in other locales, as they can introduce contaminants and disturb biofilms, potentially releasing Legionella into the water supply.

How can advanced water treatment prevent Legionnaires' disease in municipal systems?

Advanced water treatment technologies, such as reverse osmosis, effectively remove contaminants, control corrosivity, and maintain stable water chemistry, which are crucial for preventing Legionella growth. AMPAC USA designs commercial and industrial systems engineered to address these specific water treatment needs, ensuring certified and documented performance to mitigate public health risks in municipal and industrial settings.

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Jun 14, 2018·1 min read

Water Filter Water Treatment

Distribution System Operational Deficiencies Coincide with Reported Legionnaires’ Disease Clusters in Flint, Michigan

Sammy FaragAMPAC USA — June 14, 2018

Distribution System Operational Deficiencies Coincide with Reported Legionnaires’ Disease Clusters in Flint, Michigan

By Sammy Farag . June 14, 2018

The Flint water crisis, sadly, gave us a real-world lesson in how managing water systems affects Legionella risk. A study in Environmental Health showed that Legionnaires’ disease outbreaks in Flint happened at the same time and in the same places as problems with their water distribution system. Technologies like reverse osmosis offer real solutions for these kinds of water quality issues. At AMPAC USA, we build commercial and industrial systems specifically for these needs, and we have the certified performance data to prove it.

10.1021/acs.es7b01589

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