Legionella’s Resistance to Chlorine Treatment

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Lombard, IL – Through the years it has become very evident that while the water supplied in the US is some of the best quality in the world problems persist.  This fact is a combination of demographic changes, improvements in testing, and emerging pathogens. It also is obvious some of the disinfection substances and treatment methods used for over 100 years are not able to address the risks for public safety.

Chlorine treatment for shower heads

One of the primary and in some cases only disinfectants used in many places of the US are chlorine based. As evidenced by the 1993 Cryptosporidium outbreak in Milwaukee that affected over 400,000 people and lead to at least 69 deaths that chlorine and chlorine-based disinfectants are not effective against all pathogens.

The second most common waterborne pathogen in US outbreaks according to the CDC that demonstrates chlorine resistance is Legionella. To be effective all the EPA chlorine based disinfectants registered for claims specifically on Legionella with FIFRA that have specified potable water applications must be provided in levels that are  600 times above primary drinking water limits.  These chlorine based disinfectants are only validated to surface disinfection.

A study published in 2012 Legionella Pneumophila transcriptional response to chlorine treatment by Charles Bodet, Tobias Sahr, Mathieu DuPuy, Carment Buchrieser and Yann Hechard  supports that along with other chlorine resistant pathogens like Giardia and Cryptosporidium that Legionella survives in the presence of chlorine and appears to be able to adapt or become resistant at the transcriptional level.  The fact that Legionella is found in many cold water supplies that have chlorinated supplies seems logically to indicate addressing it should be focused on looking at other technologies that are specifically registered by EPA FIFRA to address them such as supplemental copper and silver ionization.

By: David Swiderski | Global Water Council

References:

http://www.cdc.gov/healthywater/drinking/public/water_diseases.html

Chart on EPA Registered Disinfectants OCT 2014 –Global Alliance for Patient and Public Safety

Legionella pneumophila transcriptional response to chlorine treatment- C. Bodet, T. Sahr, M. DuPuy, C. Buchrieser, Y. Hechard 2012 Water Research 46 808:816

David J. Swiderski is a member of the global Water Council located in Milwaukee, Wisconsin and has had a long former career in process, medical, municipal and pharmaceutical water treatment over the years along with being a consultant to the Mexican, Brazilian and Guyanese Gov’ts.

2017-05-19T14:44:29+00:00