Why do pool sanitisers need to act quickly against microorganisms?
Because different people are immersed together in the same body of water, microorganisms can quickly pass from one person to another through entry of water into the eyes, nose and mouth. A significant amount of water is accidentally swallowed while swimming. In their Guidelines for Safe Recreational-water Environments, Vol 2, WHO cites studies showing that children typically ingest 500 millilitres of water per swimming session and competitive swimmers ingest about half that amount. Human-sourced pathogenic microorganisms enter the water from the eyes, nasal discharges, saliva and skin surfaces of infected individuals. They are also introduced surprisingly often by the accidental release of faeces or vomitus into the pool. The number of pathogenic microorganisms distributed into the water from such a release can be extremely large. For example, children with diarrhoea from Shigella species or bloody diarrhoea from haemorrhagic colitis (E. coli 0157) can release 108 bacterial pathogens p
