US-based researchers have found that using a complementary form of disinfection, known as copper-silver ionization (CSI), can decrease disinfection byproducts and cell toxicity of chlorinated swimming pool water.
In a study published in the journal Environmental Science & Technology, the scientists report CSI involves generating antimicrobial copper and silver ions by electrolysis. They say that by combining this technique with reduced chlorine levels, it is possible to make swimming pools safer.
In detail, they tested the ability of CSI to reduce disinfection byproducts (DBPs), which are formed when chlorine reacts with organic matter and compounds introduced by swimmers, such as those in sweat, urine, sunscreens and cosmetics. DBPs have been linked with health problems, including respiratory issues, bladder cancer, and pregnancy and birth complications.
The experiment involved collecting water samples from two pools treated with CSI and chlorine –– one outdoor and one indoor. Once they ran their analyses, the team led by Susan Richardson from the University of South Carolina detected 71 DBPs, some of which were quantified for the first time in pools.
In trials with mammalian cells in the lab, they also found that the indoor pool samples were more toxic to cells than the outdoor samples, likely because outdoor DBPs can volatilize in the open air or degrade with sunlight over time. In indoor pool water, the lowest levels of DBP formation and toxicity were observed when the lowest amount of chlorine was used in combination with CSI.
To control for factors such as the number of swimmers, temperature and pH, the researchers also conducted experiments in simulated pools with a solution added that mimics human body fluids, and they observed similar results.
These data suggest that using CSI with lower amounts of chlorine could be a way to make swimming safer.