Inactivation of Pseudomonas aeruginosa and Aeromonas hydrophila by silver in tap water

Nadia Silvestry-Rodriguez, Kelly R. Bright, Donald R. Uhlmann, Donald C. Slack, Charles P. Gerba

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


This study was conducted to assess the efficacy of silver as a secondary disinfectant to replace or reduce the level of chlorine utilized in water distribution systems. Pseudomonas aeruginosa and Aeromonas hydrophila are opportunistic pathogens present in drinking water and have been associated with waterborne disease. After 8 hours of exposure to 100 μg/L of silver, there was a >6-log10 reduction in P. aeruginosa in tap water at room temperature at pH7 and a 5.55-log10 reduction in the presence of 3 mg/L humic acid. Similar reductions were observed at pH9. At 4°C, reductions greater than 4-log10 were observed after 24 hours. For A. hydrophila, a >6-log10 reduction occurred at both pH7 and pH9 within nine hours. The World Health Organization has determined that this amount of silver could be used for water disinfection without health risks. Furthermore, silver shows promise as a secondary disinfectant, even in the presence of organic matter in concentrations that would reduce the effectiveness of free chlorine.

Original languageEnglish (US)
Pages (from-to)1579-1584
Number of pages6
JournalJournal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering
Issue number11
StatePublished - Sep 2007


  • Aeromonas
  • Distribution systems
  • Drinking water
  • Pseudomonas
  • Residual disinfectant
  • Silver

ASJC Scopus subject areas

  • Environmental Engineering


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