Multi-scale laboratory routine in the efficacy assessment of conservative products for natural stones.

The evaluation of conservative treatments' efficacy on natural building stones are usually based on standard recommendation routines finalized to evaluate compatibility and harmfulness of products in turn of the substrate. However, the visualization and the quantification of products inside pore structure of natural stones is not immediate through standard tests, so that imaging and advanced techniques are recently proposed in material conservation field to improve knowledge on penetration depth, modification of pore-air interface at different scale and monitor dynamic absorption processes. Moreover, natural stones are usually characterized by complex structure, which changes due to conservative treatments have to be inspected at different scale (from micrometer to nanometer). In this prospective, the assessment of laboratory practices able to integrate multiscale methods and give back a complete overview on interaction between new conservative formulates and natural stones is of high interest. In this paper, we propose a methodological routine for efficacy assessment of conservative products, incorporating classical and innovative nondestructive techniques. Validation of the workflow has been verified on a high porous natural stone treated with new hybrid formulates appropriately customized for conservation issues. •The study intends to add new insights on problems related to consolidation of high porous carbonate stone, application methods in consolidating natural stones and methods to evaluate efficacy of new products.•A multi-scale laboratory investigation procedure is proposed by integrating standard and innovative nondestructive methods. Merits and limits of each applied method are discussed during validation.•The possibility to incorporate standard routines and/or substitute destructive testing with non-destructive ones seem to be a valid alternative to evaluate efficiency and monitor behavior of stones treated with consolidating products.

Illicit drugs and pharmaceuticals in swimming pool waters.

The occurrence of illicit drugs (cocaine, opioids, amphetamines and cannabis derivatives), some of their metabolites and 48 pharmaceuticals, was investigated in pool and source waters in ten Italian indoor swimming pools. The samples were analyzed by highperformance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), after solid phase extraction (SPE). Cocaine and its metabolites were found in nine swimming pools, at concentrations from 0.3 to 4.2 ng/L for cocaine, 1.1 to 48.7 ng/L for norcocaine, 0.7 to 21.4 ng/L for benzoylecgonine and 0.1 to 7.3 ng/L for norbenzoylecgonine. Opioids, amphetamines and cannabis derivatives were never detected. The most frequent pharmaceuticals were anti-inflammatory drugs: ibuprofen was found in all the pool waters, with a maximum 197 ng/L and ketoprofen was detected in 9/10 samples (maximum 127 ng/L). Among anticonvulsants, carbamazepine and its metabolite, 10,11-dihydro-10,11dihydroxycarbamazepine, were frequent in swimming pool water (8/10 samples) at concentrations up to 62 ng/L. The cardiovascular drug valsartan was also found frequently (8/10 samples), but at lower concentrations (up to 9 ng/L). Other pharmaceuticals were detected occasionally and at lower concentrations (atenolol, enalapril, paracetamol, hydroclorothiazide, irbesartan and dehydro-erythromycin). Carbamazepine, irbesartan and dehydroerythromycin were detected at very low levels (up to 5 ng/L) in only one of the four source water samples. A quantitative risk assessment showed that the health risk for humans to these substance in swimming pool waters was generally negligible, even for vulnerable subpopulations such as children and adolescents.

[Environmental surveillance of a sample of indoor swimming pools from Emilia Romagna region: microclimate characteristics and chemical parameters, particularly disinfection by products, in pool waters]. / Aspetti igienico-ambientali di un campione di piscine coperte della Regione Emilia Romagna: valutazione delle condizio- ni microclimatiche e dei principali parametri chimici delle acque, con particolare riferimento alla presenza di sottopro- dotti della disinfezione.

The aim of the present study was to investigate the environmental and healthy aspects from a representative sample of indoor swimming pools located in the Emilia Romagna region. During the sampling sessions, the occupational environment was evaluated in terms of microclimate parameters and thermal comfort/discomfort conditions. Moreover the chemical risk was assessed by analyzing from the pool water the presence of disinfection by-products (DBPs), such as: trihalomethanes (THMs), haloacetic acids (HAAs), chlorite, chlorate and bromate. The analytical results are in agreement with the Italian legislation (Accordo Stato-Regioni; 2003) even if in some of the sampled indoor swimming pools, the dosed combined chlorine levels, were greater than the Italian limit. With the regard to the microclimate conditions evaluation, the considered thermal indices, Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD%), described a satisfactory occupational environment. Among DBPs, the THMs mean levels (41.4 +/- 30.0 microg/l) resulted close to the values of the current Italian drinking water legislation, and seem to not represent an health issue. The pool waters chlorate levels (range: 5 - 19537 microg/l) need further investigations as recent epidemiological studies on drinking water hypothesized a potential genotoxicity effect of these compounds which are involved in cellular oxidative processes.

[Exposure to organic halogen compounds in drinking water of 9 Italian regions: exposure to chlorites, chlorates, thrihalomethanes, trichloroethylene and tetrachloroethylene]. / Valutazione dell'esposizione a composti organoalogenati nelle acque potabili di 9 Province Italiane: indagine sulla presenza di cloriti, clorati, trialometani, trielina e tetracloroetilene.

This study investigated the exposure to organohalogens compounds in drinking water from 9 Italian towns (Udine, Genova, Parma, Modena, Siena, Roma, L'Aquila, Napoli and Catania). Overall, 1199 samples collected from 72 waterworks were analyzed. THMs, trichloroethylene and tetrachloroethylene were evaluated using the head-space gas chromatographic technique (detection limit of 0.01 microg/l; chlorite and chlorate analysis was performed by ion chromatography (detection limit of 20 microg/l). THMs were evidenced in 925 samples (77%) (median value: 1.12 micro/l; range: 0.01-54 mciro/l) and 7 were higher than the THMs Italian limit of 30 microg/l. Chlorite and chlorate levels were higher than the detection limit in 45% for chlorite and in 34% for chlorate samples; median values were 221 microg/l and 76 microg/l, respectively. Chlorite values were higher than the chlorite Italian limit (700 microg/l) in 35 samples (8.7%). Trichloroethylene and tetrachloroethylene were measured in 29% and 44% of the investigated samples and showed values lower than the Italian limit (highest levels of 6 microg/l and 9 microg/l, respectively). The low levels detected of THMs, trichloroethylene and tetrachloroethylene have no potentials effects on human health, whereas, the levels of chlorite and chlorates should be further evaluated and their potential effects for the populations using these drinking waters, better understood.

[Halogenated volatile organic compounds in bottled mineral water and soft drinks]. / Composti Alogenati Organici Volatili (AOV) nelle acque minerali naturali e in altre bevande di largo consumo.

74 mineral natural water samples and 56 samples of different commercial drinks have been analysed by head-space chromatography in order to evidence the presence of volatile halogenated organic compounds (VHO). Trihalomethanes (THM) as drinking water chlorination by-products and trichloroethane, carbon tetrachloride, trichloroethylene and tetrachloroethylene as ubiquitarious substances have been investigated. The presence of VHO has been evidenced in 20,3% of mineral natural water samples and in the 58,9% of the commercial soft drinks: this latest group has usually shown higher levels of the investigated compounds. The results of the present study has been compared with a similar study performed in 1991 in the same area: the VHO values observed in the present study appear to be lower than those obtained in the previous study.

[Exposure to water disinfection by-products and adverse pregnancy outcomes: results of a case-control study carried out in Modena (Italy)]. / Esposizione a sottoprodotti della disinfezione delle acque potabili ed effetti sul neonato: studio caso-controllo presso l'azienda ospedaliera Policlinico di Modena.

Chlorination By Products (CBPs) in drinking water have been associated with an increased risk of adverse pregnancy outcomes, such as small term birth (STB) and preterm delivery. Up to date epidemiological evidence is weakened by a generally inaccurate exposure assessment, often at an ecological level: in this study the exposure is evaluated at the individual level. A case control study with incident cases was performed in Modena between October 1999-September 2000. 332 subjects were enrolled: 93 preterm births (26th-37th week of pregnancy), 73 STB (from 38th week, and weight less than the lowest 10th percentile) and 166 controls. Exposure was assessed both by applying a questionnaire on personal habits and by personal water sampling directly at subjects' home. THMs were analysed in all samples, chlorite and chlorate in water samples treated with chlorine dioxide. Subjects usually drinking tap water were few (5.2%): most of them were living in areas supplied by water treated with chlorine dioxide (87%). Levels of THMs were low (mean: 0.73 microgram/l), while chlorite and chlorate concentrations were relatively high (mean: 217.8 microgram/l for chlorites and 95.2 microgram/l for chlorates). Preterm birth did not show any significant association with CBPs, while STB appeared significantly associated, after adjusting for many potential confounders, with CBPs induced by chlorine dioxide treatment, especially with levels of chlorate higher than 200 microgram/l (OR: 4.7; 95%CI: 1.15-19.72). The association between STB and chlorate must be investigated further as the number of water utilities applying chlorine dioxide as disinfection treatment is increasing.

[Presence of disinfection by-products (DBPs) and other halogenated compounds in drinking water samples collected in the areas of Modena and Parma]. / Indagine sulla presenza di sottoprodotti della clorazione (Disinfection By-Products: DBPs) ed altri composti alogenati nelle acque potabili di Modena e Parma.

The Authors report data about the presence of Disinfection By-Products (DBPs) and other halogenated compounds in drinking water samples collected in the areas of Modena and Parma (20 water supplies). Trihalomethanes, chlorite and chlorate (only in water samples treated with chlorine dioxide), and halogenated compounds were investigated. On the whole, trihalomethanes were evidenced in the 85% of the samples (n. 285) at low levels, while chlorite and chlorate were present in the 67% and 63% of the treated samples with chlorine dioxide (257 samples). Chlorite mean and median values were 225.70 microg/l and 136.75 microg/l respectively, ranging from 20 to 2000 microg/l. Chlorate concentrations were lower than chlorite: the mean value was 102.93 mg/l, while median level was 50 microg/l (range: 20-1500 microg/l). The high concentrations of chlorite and the wide range of values within each municipality plant in Modena and Parma suggest to investigate further in order to evaluate the human exposure in drinking water thoroughly.

Air quality and well-being perception in subjects attending university libraries in Modena (Italy).

We studied four libraries in the University of Modena and Reggio Emilia (Northern Italy) to determine the presence of polluting agents such as total dusts, formaldehyde and other volatile organic compounds (VOCs) including benzene, toluene and xylenes and to assess the sense of well-being perceived by library users. This investigation was suggested by an increase in reported symptoms related to Sick Building Syndrome (SBS) observed in recent decades among people spending most of their time in various indoor environments, including libraries. The microclimatic conditions and the concentrations of pollutants indicated an acceptable situation on the whole, even though a wide range of total dust values (40-350 microg/m3) and total VOCs (203-749 microg/m3) was observed. However, the perception of the different environmental parameters by the 130 library users that were interviewed identified the existence of some discomfort mainly caused by the feeling of poor ventilation. Moreover, 78.5% of the subjects stated they had at least one of the 16 investigated symptoms potentially related to a SBS. The place of occurrence of the self-reported symptoms was also investigated, the symptoms arising during library attendance more frequently than elsewhere were only four, and in particular feeling hot, sore eyes, dry throat and breathing difficulties. Overall, our study has shown the existence of an association between microclimatic perceptions as reported by library users and subjective symptoms related to SBS, considering the four libraries separately, the highest prevalence of self-reported symptoms was found in the library where environmental discomfort as perceived by users was greatest. Nevertheless, an association between subjective self-reported symptoms and both microclimatic conditions as resulted by instrumental measurements and/or pollutants concentrations was not apparent.

Occupational exposure to trihalomethanes in indoor swimming pools.

The study evaluated occupational exposure to trihalomethanes (THMs) in indoor swimming pools. Thirty-two subjects, representing the whole workforce employed in the five public indoor swimming pools in the city of Modena (Northern Italy) were enrolled. Both environmental and biological monitoring of THMs exposure were performed. Environmental concentrations of THMs in different areas inside the swimming pools (at the poolside, in the reception area and in the engine-room) were measured as external exposure index, while individual exposure of swimming pool employees was estimated by THMs concentration in alveolar air. The levels of THMs observed in swimming pool water ranged from 17.8 to 70.8 microg/l; the mean levels of THMs in ambient air were 25.6+/-24.5 microg/m3 in the engine room, 26.1+/-24.3 microg/m3 in the reception area and 58.0+/-22.1 microg/m3 at the poolside. Among THMs, only chloroform and bromodichloromethane were always measured in ambient air, while dibromochloromethane was detected in ambient air rarely and bromoform only once. Biological monitoring results showed a THMs mean value of 20.9+/-15.6 microg/m3. Statistically significant differences were observed according to the main job activity: in pool attendants, THMs alveolar air were approximately double those observed in employees working in other areas of the swimming pools (25.1+/-16.5 microg/m3 vs. 14.8+/-12.3 microg/m3, P < 0.01). THMs in alveolar air samples were significantly correlated with THMs concentrations in ambient air (r = 0.57; P < 0.001). Indoor swimming pool employees are exposed to THMs at ambient air levels higher than the general population. The different environmental exposure inside the swimming pool can induce a different internal dose in exposed workers. The correlation found between ambient and alveolar air samples confirms that breath analysis is a good biological index of occupational exposure to these substances at low environmental levels.

Two-year evolution of perchloroethylene-induced color-vision loss.

Progression of perchloroethylene-induced color-vision impairment was studied in 33 dry-cleaner workers at 12 establishments in Modena, Italy. In an initial survey, we evaluated exposure with personal passive samplers, and we assessed color vision with the Lanthony D-15 desaturated panel. Two years later, workers were reexamined. In 19 workers (subgroup A), exposure to perchloroethylene had increased (median of 1.7 ppm versus 4.3 ppm, respectively), whereas in the remaining 14 workers (subgroup B) exposure was reduced (2.9 ppm versus 0.7 ppm, respectively). Color vision worsened in subgroup A, but no vision changes were apparent in subgroup B. The results indicated that an increase in exposure during a 2-y period, even if slight, can cause color vision to deteriorate. A similar slight reduction in exposure did not lead to color-vision improvement; perhaps this lack of improvement resulted from (a) an insufficient reduction in exposure, (b) an insufficient reduction in duration of exposure, or (c) irreversible perchloroethylene-induced color-vision loss.

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 (CHC13), bromodichloromethane (CHBrC12), dibromochloromethane (CHBrsC1) and bromoform (CHBr3). CHC13 appeared the most represented compound both in water and in environmental air before and after swimming. CHBrC1w and CHBr2C1 were always present, even though at lower levels than CHC13, CHBr3, was rarely present. In relation to biological monitoring, CHC13, CHBrC12 and CHBr2C1 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 micrograms/m3, respectively, while after spending 1 h swimming, higher levels were detected (75.6 +/- 18.6, 6.5 +/- 1.3 and 1.4 +/- 0.9 micrograms/m3, respectively). Only CHC13 was detected in all plasma samples (mean: 1.4 +/- 0.5 micrograms/1) while CHBrC1x and CHBr2C1 were observed only in few samples at a detection limit of 0.1 micrograms/1. After 1 h at rest, at an average environmental exposure of approx. 100 micrograms/m3, the THM uptake was approx. 30 micrograms/h (26 micrograms/h for CHC1c, 3 micrograms/h for CHBrC12 and 1.5 micrograms/h for CHBr2C1). After 1 h swimming, the THM uptake is approx. seven times higher than at rest: a THM mean uptake of 221 micrograms/h (177 micrograms/h, 26 micrograms/h and 18 micrograms/h for CHC13, CHBrC12 and CHBr2C1, respectively) was evaluated at an environmental concentration of approx. 200 micrograms/m3.

Indoor air quality in the university libraries of Modena (Italy).

We carried out a survey in 16 libraries of the University of Modena, Northern Italy, to assess the indoor exposure to volatile organic compounds (VOCs), including formaldehyde, and total dusts. Data were collected on the main structural characteristics of the buildings; indoor microclimate parameters, such as temperature, relative humidity and ventilation rate were measured and air samples taken inside and outside the libraries. The mean value of total dusts was 190 +/- 130 microg/m3 with a wide range of values. Formaldehyde was found in only ten out of 16 libraries and the indoor concentrations ranged from 1.70 to 67.8 microg/m3 with an average value of 32.7 +/- 23.9 microg/m3. On the whole, VOCs were present in all the libraries investigated with an average value was 433 +/- 267 microg/m3 (range 102-936 microg/m3). No correlation was found among VOCs, formaldehyde and total dusts nor was a significant association observed with microclimatic parameters or the structural characteristics of the buildings. The general situation found in this study suggests no major problems related to indoor pollution. However, some of the pollutants investigated such as total dust and total VOCs deserve further investigation. It is important to identify the possible sources of contaminants and to define the relationship between indoor and outdoor levels of pollutants more accurately, taking into account the effects of air recycling due to natural ventilation systems.

Environmental and biological monitoring of chloroform in indoor swimming pools.

The presence of chloroform as the result of disinfection with sodium hypochlorite was demonstrated in the water and ambient air of indoor swimming pools. Environmental monitoring was performed in 12 indoor swimming pools in northern Italy and the level of human exposure was assessed. Biological monitoring performed by gas chromatography on human plasma and alveolar air samples evidenced that the uptake of chloroform in swimmers varies according to the intensity of the physical activity and age. The elimination of chloroform in alveolar air in one subject showed a very short half-life (from 20 to 27 min) and a complete clearance within 10 h after the end of exposure.

Occupational and environmental exposure to perchloroethylene (PCE) in dry cleaners and their family members.

Perchloroethylene exposure in 28 dry-cleaning establishments and in 25 homes occupied by dry cleaners in Modena, Italy, was investigated. Environmental air samples and alveolar air samples from dry cleaners (n = 60) and from their family members (n = 23) were collected. The degree of perchloroethylene on the dry-cleaning premises varied widely from establishment to establishment. Spot sampling ranged from 0.6 to 75 mg/m3, whereas sampling by personal passive dosimeters ranged from 2.6 to 221.5 mg/m3 (8-h time weighted average values). Perchloroethylene in alveolar air samples collected at the end of the work day correlated closely with the 8-h time weighted average values (r = .750, p = .001), and correlated also with alveolar air samples collected at home in the evening (r = .665, p = .001) and the following morning (r = .549, p < .001). Perchloroethylene levels inside the homes of dry cleaners appeared significantly higher than in 29 houses selected as controls (Mann Whitney U test, p < .001). Perchloroethylene in alveolar air samples collected at home suggests that nonoccupational exposure to perchloroethylene for family members of dry cleaners exists.

Indoor exposure to perchloroethylene (PCE) in individuals living with dry-cleaning workers.

Perchloroethylene (PCE) is the most widely used solvent in dry-cleaning; it is toxic to the liver, kidney and central nervous system and may be a human carcinogen. PCE levels in the ambient air of dry-cleaners' homes were measured, and samples of end-exhaled air (alveolar air) from subjects who were not themselves occupationally exposed, but who were members of the household of dry-cleaners were compared with samples from the general population. Thirty apartments were visited housing dry-cleaners and their families, and located well away from the dry-cleaning premises. Indoor air samples and alveolar air samples were collected contemporaneously from the dry-cleaners (36) and members of their household (34). The same sampling procedure was followed in 25 private homes where samples of alveolar air were collected from 41 subjects who were not occupationally exposed and who acted as control group. All the samples were analysed by direct-injection gas-chromatography. PCE levels in dry-cleaners' homes proved to be significantly higher than in control houses (geometric means: 265 vs. 2 micrograms/m3, P < 0.001). PCE levels in the alveolar air exhaled by dry-cleaners, their family members and control subjects were statistically different (geometric means: 5140, 225 and 3 micrograms/m3, respectively; P < 0.001). PCE is a ubiquitous substance in indoor air, but is present at higher concentrations in apartments where dry-cleaners and their families live. Biological monitoring of PCE in alveolar air confirms that family members of dry-cleaners are more exposed than the general population.

Dietary iron deficiency in the rat. II. Recovery from energy metabolism derangement of the hepatic tissue by iron therapy.

Severe iron deficiency in rats was found to be associated with abnormal lipid accumulation in the liver and impairment of the oxidative metabolism in the hepatic tissue. Iron therapy, consisting in oral administration to iron-deficient 4-week-old rats of iron succinyl-albumin complex, at a daily dose of 10 mg/kg body weight, over a period of 7 days, almost completely corrected these functional anomalies. This treatment fully reverted severe anemia associated with iron deficiency. The level of iron in the hepatic tissue and in the mitochondrial fraction also increased largely. By contrast, no significant improvement in the lowered level of cytochromes occurred. Iron supplements significantly decreased the abnormal level of liver total lipids and serum triglycerides. Concomitantly, iron repletion fully reverted the partial loss of coupled function in isolated mitochondria and the energy state perturbation of the liver. A close relationship among abnormal lipid accumulation, impairment of mitochondrial oxidative phosphorylation and energy derangement in the hepatic cell in this experimental model of severe dietary iron deficiency anemia appears to be likely.

Chloroform in alveolar air of individuals attending indoor swimming pools.

Alveolar air samples were collected from 163 subjects at indoor swimming pools and from 77 nonexposed subjects. Chloroform was present in all samples collected from exposed subjects (median = 695.02 nmol/m3). It was found at very low levels in 53% of samples from nonexposed subjects. Alveolar air chloroform levels from people attending indoor swimming pools (mean value within each sampling session) were correlated with environmental air concentration (r = 0.907, p = .002). Analysis of variance showed that levels of chloroform in alveolar air depend on environmental air concentration, age, intensity of the sport activity, and kind of swimming. Chloroform levels in samples collected from competitive swimmers versus nonswimming visitors were different (F = 10.911, p = .001). Moreover, their pattern of swimming may affect chloroform concentration in alveolar air. The analysis of chloroform in alveolar air assesses indoor exposure in healthy subjects simply and at low cost.

Synthesis, structure, antimicrobial, and genotoxic activities of organotin compounds with 2,6-diacetylpyridine nicotinoyl- and isonicotinoylhydrazones.

A series of organotin compounds obtained from the reaction of 2,6-diacetylpyridine nicotinoyl- and isonicotinoylhydrazones with tri- and diorganotin chlorides was investigated. The IR and 119Sn NMR spectroscopic characterization of all the compounds is reported, together with the x-ray crystal structure of [SnEt2(H2dapin')]2[SnEt2Cl3]Cl3.2H2O (H2dapin' = 2,6-diacetylpyridine bis(isonicotinoylhydrazone)). The main feature in this compound is the presence of a tin atom in both the complex ionic units. The coordination polyhedron is a pentagonal bipyramid in the cation and a trigonal bipyramid in the anion. Results are discussed concerning the in vitro evaluation of antimicrobial properties and genotoxic potential of the compounds described. In all cases the complexes show a reduced antimicrobial activity as compared to that of the corresponding organotin compound. Genotoxic properties of the ligands, detected in the Ames test, disappear in the complexes.

A 31P-NMR study on the energy state of rat liver in an experimental model of chronic dietary iron overload.

31P-NMR spectroscopy of rat liver perchloric acid extracts was utilized to assess the hepatic energy state in an experimental model of chronic dietary iron overload. Oral administration of iron for a period of 65 days that induces a steady ten-fold increase in hepatic iron concentration causes a significant decrease in the hepatic ATP level not associated with appreciable modifications of ADP and Pi levels. The phosphorylation ratio appears on the average decreased. The values of the energy state parameters revert to the normal if the concentration of iron in the liver is reversed below the critical level upon withdrawal of iron treatment after 45 days for a period of 20 days. The implication of these energy modifications for the pathogenesis of cell damage in the siderosis is discussed.

Plasma chloroform concentrations in swimmers using indoor swimming pools.

This study evaluated swimmers and visitors who were exposed to chloroform (CHCl3) at three indoor swimming pools in Modena, Italy. Chloroform was measured in plasma samples of 127 subjects present at the pools and in 40 nonexposed subjects. The analyses were performed by head-space gas chromatography. Chloroform was present in all samples collected from the 127 subjects who attended the pools (median = 7.5 nmol/l; range = 0.8-25.1 nmol/l). Agonistic swimmers who trained for competitions showed a significantly higher mean value of plasma CHCl3 than nonagonistic swimmers and visitors. Plasma CHCl3 levels were significantly correlated with (a) CHCl3 concentrations in water and in environmental air, (b) the number of swimmers in the pools, and (c) the time spent swimming. Covariance analysis showed that plasma CHCl3 levels also depended on the intensity of the sport activity (total explained variance = 67.4%).