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 (CHCl3), bromodichloromethane (CHBrCl2), dibromochloromethane (CHBr2Cl) and bromoform (CHBr3). CHCl3 appeared the most represented compound both in water and in environmental air before and after swimming. CHBrCl2 and CHBr2Cl were always present, even though at lower levels than CHCl3. CHBr3 was rarely present. In relation to biological monitoring, CHCl3, CHBrCl2 and CHBr2Cl 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/m3, 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/m3, respectively). Only CHCl3 was detected in all plasma samples (mean: 1.4±0.5 μg/l) while CHBrCl2 and CHBr2Cl 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/m3, the THM uptake was approx. 30 μg/h (26 μg/h for CHCl3, 3 μg/h for CHBrCl2 and 1.5 μg/h for CHBr2Cl). 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 CHCl3, CHBrCl2 and CHBr2Cl, respectively) was evaluated at an environmental concentration of approx. 200 μg/m3.