Blood and breath analyses as biological indicators of exposure to trihalomethanes in indoor swimming pools

In this article, exposure to trihalomethanes (THMs) in indoor swimming pools as a consequence of water chlorination is reported. Environmental and biological monitoring of THMs was performed in order to assess the uptake of these substances after a defined period in five competitive swimmers, regularly attending an indoor swimming pool to train for competition during four sampling sessions. Analyses were performed by gas-chromatography and the following THMs were detected: chloroform (CHCl 3), bromodichloromethane (CHBrCl 2), dibromochloromethane (CHBr 2Cl) and bromoform (CHBr 3). CHCl 3 appeared the most represented compound both in water and in environmental air before and after swimming. CHBrCl 2 and CHBr 2Cl were always present, even though at lower levels than CHCl 3. CHBr 3 was rarely present. In relation to biological monitoring, CHCl 3, CHBrCl 2 and CHBr 2Cl were detected in all alveolar air samples collected inside the swimming pool. Before swimming, after 1 h at rest at the pool edge, the mean values were 29.4±13.3, 2.7±1.2 and 0.8±0.8 μg/m 3, respectively, while after spending 1 h swimming, higher levels were detected (76.5±18.6, 6.5±1.3 and 1.4±0.9 μg/m 3, respectively). Only CHCl 3 was detected in all plasma samples (mean: 1.4±0.5 μg/l) while CHBrCl 2 and CHBr 2Cl were observed only in few samples at a detection limit of 0.1 μg/l. After 1 h at rest, at an average environmental exposure of approx. 100 μg/m 3, the THM uptake was approx. 30 μg/h (26 μg/h for CHCl 3, 3 μg/h for CHBrCl 2 and 1.5 μg/h for CHBr 2Cl). After 1 h swimming, the THM uptake is approx. seven times higher than at rest: a THM mean uptake of 221 μg/h (177 μg/h, 26 μg/h and 18 μg/h for CHCl 3, CHBrCl 2 and CHBr 2Cl, respectively) was evaluated at an environmental concentration of approx. 200 μg/m 3.