Swimming in chlorinated pools can cause an increased risk of cancer in bathers, Spanish researchers said on Monday.
Researchers from the Barcelona-based Centre of Research in Environmental Epidemiology (CREAL) and Research Institute Hospital del Mar studied changes in indicators of mutagenicity -- permanent mutation of the DNA -- among a group of swimmers in an indoor chlorinated pool.
"The evidence of genotoxic effects were observed in 49 healthy adults after swimming for 40 minutes in a chlorinated indoor pool," CREAL said in a statement on Monday.
Researchers found indicators of an increase in cancer risk in healthy subjects as well as potential respiratory effects from the cholorine used as a disinfectant, the statement said.
The study was published on Sunday in the US journal Environmental Health Perspectives.
The co-director of CREAL, Manolis Kogevinas, said the findings should not put people off swimming.
"The positive health impacts of swimming can be increased by reducing the levels of these chemicals," he said.
"In no case do we want to stop swimming, but to encourage the reduction of chemicals in swimming pools," said Kogevinas, who suggested the problems caused by a reduction in levels of disinfectant could be offset if swimmers showered before taking a dip, wore bathing caps and refrained from urinating.
Genotoxic Effects in Swimmers Exposed to Disinfection By-products in Indoor Swimming Pools, Manolis Kogevinas, et al., Environ Health Perspect. doi:10.1289/ehp.1001959