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I ' F Chloroform enters the body through the respiratory ronmental air samples collected at the surface of the system, the skin, and the gastrointestinal tract. Very lit- pool and samples collected within 150 cm in height. tie information is available on chloroform metabolism These variations resulted mainly from water turbulence in humans, and few data exist on biological indicators caused by the swimmers. Given that sampling at the for exposure in humans. water surface can cause contamination by splashing, f In our previous studies, chloroform concentration in we decided to take three air samples at a height of 150 blood samples of people attending indoor swimming cm as representative of environmental chloroform con- pools was evaluated. Plasma levels appeared signifi- centrations. Three samples of water were taken at three cantly correlated with concentration in water and in different points in the pool at a depth of 20 cm near the environmental air, the number of swimmers in the edge of the pool. Environmental air samples, used as pool, the time spent swimming, and the intensity of the controls, were collected inside the Department of Hy- activity.9 1 giene of the University of Modena. Alveolar air samples It is not easy to collect blood samples in large sur- from nonexposed subjects were collected in the same veys; therefore, the feasibility of end-exhaled air (alveo- place. lar air) sampling was investigated. Alveolar air analysis Analytical methods. Samples of environmental air can be used to assess exposure and intake, not only in and water samples were collected in screw-capped 40 ` F occupational but also in environmental exposure."," cm' glass vials with teflon-faced silicone rubber septa. 1 This paper presents a study of chloroform in alveolar air Vials used for water collection were treated with 5 mg samples collected from nonexposed subjects and from of sodium thiosulphate immediately before sampling to .fi people attending indoor swimming pools. The relation- quench residual chlorine reactions. Determination of ship between alveolar air levels and environmental chloroform in water was performed according to our and/or personal factors that can influence intake of previous studies.' chloroform was also investigated. Determination of chloroform in environmental and alveolar air was performed by injecting samples directly Materials and methods into the gas chromatograph (Varian 3400) using a gas- light syringe (Hamilton). The analytical procedure has Subjects. The study was performed in eight sampling been described previously and was the same used for sessions from November 1989 through October 1990 the determinations of chloroform in water.' Calibration in two indoor swimming pools in the city of Modena, It- was performed by external standard methods, given aly. A total of 163 subjects, swimmers and nonswim- the considerable difficulty of applying the internal stan- ming visitors regularly attending indoor swimming dard method to direct gas analysis. Precision, calculat- pools, was investigated. A sample of 77 subjects who ed from five duplicate determinations on 5 different d, 1 did not attend indoor swimming pools was also exam- was 3.5% as coefficient of variation. The detection limit ined. A well-trained staff interviewer asked for informa- was 8.4 nmol/m'. The chloroform identity was confirmed } tion about personal data and possibility of exposure by gas chromatography-mass spectrometry (GC-MS) outside the swimming pool (e.g., occupational expo- with the following procedure: environmental air sam- sure or handling of solvents at home while engaged in pies were collected inside the swimming pools on Car- hobby activities). Exposure via drinking water was ex- botrap"' 300 Multi-bed Thermal Desorption tubes (Su- cluded because the city of Modena is supplied with pelco) and were injected using thermal desorption cold water treated with chlorine dioxide, and the water is trap injector (Chromopack) into a GC-MS system (GC: free from chloroform and other trihalomethanes. The I-1p 5990, MS: 5989A, Hewlett-Packard). The chloro- 163 subjects-98 males and 65 females, aged 5 to 44 form identification was based on retention times meas- y—were classified into three groups according to the ured on a total ion-current chromatogram, on mass physical activity practiced in the swimming pool: (1) chromatograms of the molecular ion, and the most sig- beginners (n - 12), (2) competitive swimmers (n - nificant fragments of chloroform (m/t 47-50, 82-87, ` 120), and (3) nonswimming visitors (n e 31). The time and 117-124). spent in the swimming pool building and/or swimming Statistical methods. Differences between exposed inside the pool was the same for every subject (i.e., 90 and nonexposed subjects were calculated according to min). Student's I test (separate variance estimate). The corre- Sampling. Alveolar air sampling was performed for lations between parameters were evaluated by Pearson all 163 exposed subjects inside the swimming pool en- correlation coefficient. Moreover, to evaluate the influ- vironment at the end of the session. Alveolar air sam- ence of some parameters on chloroform content in al- ples were collected in 34-cm' one-way glass tubes veolar air, analysis of variance (ANOVA) and analysis of equipped with two valves. Subjects were asked to covariance (ANCOVA) were performed, and differenc- breath normally into the tube with open valves. At the es among mean values were evaluated by the Student- end of expiration, the valves were closed. For analysis, Neuman Keuls test (p < .05). Inasmuch as exposure the tubes were heated to 37°C to recreate the condi- data were not normally distributed, logarithmic trans- tions at the time of the sampling. During each session in formation was performed for all data when tests re- file swimming pool, three environmental air samples quired it. Tests were always checked for homogeneity were collected at a height of 150 cm above the water of variance according to the Cochran and Bartlett tests. surface at the edge of the pool. Previous samplings had All statistical analyses were carried out with SPSS/PC shown random variations in chloroform levels in envi- and BMDP/PC statistical packages.1"' July/August 1993(Vol.48(No.411 251 L