Exhaled breath of children swimmers conveniently collected in Teflon bags and used for trihalomethane determination by SPME-GC-MS.

Trihalomethanes (THMs) are the most common disinfection by-products in swimming pools; however, they exhibit strong cytotoxicity and genotoxicity, posing health risks. Children are more vulnerable to swimming-related health risks than adults; therefore, a rapid and accurate assessment of internal THM exposure in children swimmers is important for health risk assessment. For internal exposure measurement, collecting exhaled breath samples is more convenient, non-invasive, and easier to perform than collecting blood and urine. Therefore, this study aimed to develop a rapid, accurate, and reproducible method for determining THMs in children swimmers' exhaled breath using solid-phase microextraction (SPME)-gas chromatography-mass spectrometry (GC-MS). The factors influencing the pretreatment procedure, including selecting SPME fibers, extraction temperature, and time, were systematically evaluated. Under the optimized conditions, the instrumental linearity range was 1-200 ng L^-1 with correlation coefficients >0.998. The limit of detection for this method was 0.3-0.5 ng L^-1. The recovery values ranged between 76.87 and 111.49%. Detecting THMs at three different calibration levels using this method had an intra-day precision of 1.31-5.07%, while the inter-day precision was 1.59-11.10% (n = 6). Additionally, the SPME-GC-MS method was used to detect the concentration of THMs in children swimmers' exhaled breath before and after swimming. Trichloromethane was the most abundant THM in the air around the pool and children's exhaled breath, and THM concentrations in the children swimmers' exhaled breath increased significantly after swimming. This study found no significant differences in the concentrations of THMs in the children swimmers' exhaled breath with different swimming durations or frequencies, which may be a result of the unrepresentative sample population and small sample size, and more in-depth and comprehensive studies are needed to verify this conclusion.