Copper-silver ionization

Copper-silver ionization is a disinfection process, primarily used to control Legionella, the bacteria responsible for Legionnaires' disease. There is strong evidence that treating water supplies in hospitals with this technique decreases the risk. Ionization can be an effective process to control Legionella in potable water distribution systems found in health facilities, hotels, nursing homes, and large buildings. In 2003, ionization became the first such hospital disinfection process to have fulfilled a proposed four-step modality evaluation; by then it had been adopted by over 100 hospitals. Additional studies indicate ionization is superior to thermal eradication. A 2011 review found copper-silver ionization to be the only Legionella control technology which has been validated through a proposed four-step modality evaluation (need reference or description of 'modality' in this context since it does not apply in all situations). Copper-silver ionization technology is recognized by the World Health Organization (WHO), the U.S. Environmental Protection Agency (EPA) to control Legionella within potable water distribution networks found in hospitals, hotels and other large type facilities. The level of ions generated has been reported to be usually below EPA Safe Water Drinking Act Lead and Copper Rule AL for copper. The AL for copper in potable water is 1.3 ppm (Cu) and the SCL for silver is 0.1 ppm (Ag) (which is the same as 100 ppb). It is important to collect and handle samples correctly in order to get accurate results. Suboptimal timing of specimen shipment for testing at reference laboratories may contribute to silver concentration above recommendations. Industry leaders who manufacture copper-silver ionization technology recommend a copper concentration of 0.4 to 0.8 ppm and a silver concentration of 40 to 60 ppb, which are compliant with EPA drinking water standards. The British Health and Safety Commission regulates U.K. ionization, advising regular system monitoring to ensure ions reach all water circuits. Also, copper in drinking water is limited to 2 ppm (mg/L) by the European Community whereas Legionella control only requires 0.4 to 0.8 ppm in concentration...well below the permissible limits. Headquarters (ECH) in Brussels, Belgium, and silver is not prescribed by the ECH.