Exposure to disinfection by-products in swimming pools demonstrated potential genotoxic effects

Kogevinas M. Environ Health Perspect. 2010;doi:10.1289/ehp.1001959.

Researchers noted an increase in genotoxicity biomarkers in individuals exposed to brominated trihalomethanes in swimming pools.

Findings from previous studies showed that exposure to disinfection by-products in drinking water was linked to cancer risk. An elevated risk for bladder cancer among those using swimming pools was also previously documented in a recent study.

To assess the potential association between disinfection by-products in swimming pools and biomarkers of genotoxicity, researchers examined blood, urine and exhaled air samples of 49 nonsmoking adults.

They assessed associations between concentrations of four trihalomethanes and changes in micronuclei and DNA damage in peripheral blood lymphocytes before and 1 hour after swimming, urine mutagenicity before and 2 hours after swimming, and micronuclei in exfoliated urothelial cells before and 2 weeks after swimming.

Trihalomethanes levels increased by about seven times after swimming: The average total trihalomethanes level was 1.2 mcg/m³ before swimming and 7.9 mcg/m³ after swimming.

In multivariate analysis, the change in the frequency of micronucleated lymphocytes after swimming increased in association with exhaled concentrations of bromodichloromethane (1.92; 95% CI, 0.21-3.63), chlorodibromomethane (1.71; 95% CI, –0.02 to 3.44) and bromoform (5.04; 95% CI, 1.23-8.84).

There was a significant increase in urine mutagenicity after swimming associated with concentration of exhaled bromoform (5.27; 95% CI, 1.80-8.75).

There were no significant associations with changes in micronucleated urothelial cells. No associations were detectable for swimming and DNA damage.

These findings are should be verified in larger studies, according to the researchers.

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