Journal of Environmental Health Volume 51, Number 5

Abstract - "Electrolytically generated copper.silver ions were evaluated as an alternative disinfectant to high levels of chlorination in swimming pools. Pure cultures of Escherichia coli and Streptococcus faecalis were individually tested by inoculating autoclaved well water with and without 0.20 mg/L free chlorine. Coppersilver ions in combination with free chlorine reduced bacterial numbers more rapidly than chlorine or coppersilver ions alone. Numbers of S. faecalis also were reduced more in the combined system than in the system containing only free chlorine when exposed for 0.5 min. The addition of coppersilver ions allowed concentrations of free chlorine to be reduced to 0.20 mg/L while still being able to meet guidelines for commercial swimming pool disinfectants,"

"In the United States, 95 percent of water disinfection is achieved using chlorine. Chlorine routinely is added to swimming pools to achieve concentrations of 0.6 - 1.0 mg/L free available chlorine. Noticeable chlorine odor usually occurs at concentrations greater than 0.6 mg/L. High concentrations also may also cause irritations of the eyes, mucus membranes and skin, creating considerable discomfort for swimmers."

"As alternative to chlorine compounds, electrolytically generated copper and silver ions have been introduced recently as a relatively safe and odorless method for water disinfection."

"Both copper and silver are bactericidal and virucidal and copper has been shown to be algicidal and possess fungicidal properties."

"In experiments using standard procedures, E. coli numbers were more effectively reduced by the combination of copper silver ions and free chlorine than with free chlorine alone. In the copper silver ions with the free chlorine system, the numbers of E. coli were reduced 3.5 log 10 in 0.5 minutes. The system containing free chlorine alone inactivated E. coli numbers 2.8 log 10 in 0.5 minutes."

"The levels of copper and silver to be used in swimming pools apparently would not pose any health risks. Standards for copper levels in drinking water were established more for aesthetics than for health concerns."

"The use of copper and silver with low levels of chlorine as a method of commercial swimming pool disinfection, thus, should greatly outweigh the negative aspects of high level chlorination, such as eye and skin irritation."

"The data obtained indicate that a system of electrolytically generated coppersilver ions with concurrent low level of free chlorine in water appears to have an enhanced effect in reducing microbial numbers. This would allow the level of chlorine currently recommended for commercial swimming pools to be reduced."